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Background and Objectives: One of the major challenges in training neurosurgical and orthopedic residents the technique for minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is the lack of visualization of surgical landmarks (pedicle, pars, lamina). This is due to the limited access to the bony spine through a tubular retractor, in addition to a smaller working corridor or patient-specific factors such as bony overgrowth, disk space collapse, and listhesis. These factors increase the possibility for surgical error and prolonged surgery time. With augmented reality (AR), relevant surgical anatomy can be projected directly into the user's field of view through the microscope. The purpose of this study was to assess the utility, accuracy, efficiency, and precision of AR-guided MIS-TLIF and to determine its impact in spine surgery training., Methods: At 2 centers, 12 neurosurgical residents performed a one-level MIS-TLIF on a high-fidelity lumbar spine simulation model with and without AR projection into the microscope. For the MIS-TLIF procedures with AR, surgical landmarks were highlighted in different colors on preoperative image data . These landmarks were visualized in the spinal navigation application on the navigation monitor and in the microscope to confirm the relevant anatomy. Postprocedural surveys (National Aeronautics and Space Administration Task Load Index) were given to the residents., Results: Twelve residents were included in this trial. AR-guided procedures had a consistent impact on resident anatomical orientation and workload experience. Procedures performed without AR had a significantly higher mental demand ( P = .003 ) than with AR. Residents reported to a significantly higher rate that it was harder work for them to accomplish their level of performance without AR ( P = .019 )., Conclusion: AR can bring a meaningful value in MIS teaching and training to confirm relevant anatomy in situations where the surgeon will have less direct visual access. AR used in surgical simulation can also speed the learning curve., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Background Context: In cases of basilar invagination-atlantoaxial dislocation (BI-AAD) complicated by atlas occipitalization (AOZ), the approach to cranial end fixation has consistently sparked debate, generally falling into two categories: C1-C2 fixation and occipitocervical fixation. Several authors believe that C1-C2 fixation carries a lower risk of fixation failure than occipitocervical fixation., Purpose: To study the biomechanical differences among 3 different cranial end fixation methods for BI-AAD with AOZ., Study Design: This was a finite element analysis., Patient Sample: A 35-year-old female patient diagnosed with congenital BI-AAD and AOZ., Outcome Measures: range of motion (ROM), peak von Mise stress (PVMS), cage micro-subsidence, cage micro-slippage., Method: Four finite element models were constructed, including unstable group (BI-AAD with AOZ), C1 lateral mass screw group, occipital plate group, occipitocervical rod group. The flexion and extension (FE), lateral bending (LB) as well as axial rotation (AR) were simulated under a torque of 1.5 Nm. Parameters include C1-C2 ROM, PVMS on screw-rod construct, cage micro-subsidence, cage micro-slippage., Results: The ROM of the C1 lateral mass screw group was smaller than that of the other fixation groups in LB and AR, but not FE. Compared with the occipitocervical rod group, the ROM in LB and AR of the occipital plate group was higher, but not in FE. The PVMS of C1 lateral mass screw group was significantly higher than that of the other groups. The ROM and PVMS of the occipitocervical rod group were in between the other 2 groups. Regarding the screws at the cranial end, the PVMS of the 4-screw occipitocervical rod group was significantly lower than that of the other groups. In general, the cage micro-motion follows the ascending order: C1 lateral mass group < occipitocervical rod group < occipital plate group., Conclusions: In cases of BI-AAD with AOZ, the C1 lateral mass screw group provided the least ROM and cage micro-motion, but the screw-rod PVMS was the largest. The advantage of occipital plate fixation lies in the lowest screw-rod PVMS, but the ROM and cage micro-motion is the highest. Four-screw fixation at the cranial end of occipitocervical rod group helps to reduce the PVMS and may prevent screw failure at the cranial end., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Study Design: This was a multicenter retrospective cohort study., Objective: We investigated the incidence of postoperative shoulder imbalance (PSI) and its risk factors in patients with Lenke types 1 and 2 scoliosis corrected using vertebral coplanar alignment (VCA)., Summary of Background Data: PSI in scoliosis affects patient quality of life. While other correction methods have reported a high correction rate for the main thoracic curve (MTC) in relation to PSI, this correlation has not been confirmed for the VCA technique., Materials and Methods: We studied 176 patients with Lenke types 1 and 2 scoliosis who underwent posterior corrective fusion surgery using the VCA technique at 11 institutions. At 2 years postoperatively, patients were divided into two groups based on radiographic shoulder height (RSH): PSI- (RSH<2 cm) and PSI+ (RSH ≥2 cm) groups. We analyzed the risk factors for PSI., Results: The overall incidence of PSI 2 years postoperatively was 11.4% (20/176), with 9.2% (11/119) and 15.8% (9/57) in patients with Lenke types 1 and 2, respectively. Contrary to a previous study, a high MTC correction rate did not emerge as a risk factor for PSI. Instead, preoperative left shoulder elevation, low postoperative thoracic kyphosis, greater T1 tilt, and high apical vertebral body-to-rib ratio were associated with PSI in patients with Lenke type 1. Preoperative left shoulder elevation and a low postoperative proximal thoracic curve (PTC) correction rate were identified as risk factors for PSI in patients with Lenke type 2., Conclusion: Our results suggest that proper PTC correction, rather than compromising MTC correction, may help prevent PSI in the VCA technique. This method is particularly advantageous for addressing Lenke type 1 scoliosis and yields favorable outcomes in shoulder balance. Patients with preoperative left shoulder elevation, especially Lenke type 2, are at high risk of developing PSI., Level of Evidence: Level 4., Competing Interests: H.T. received a scholarship donation from Medtronic Sophamore Danek Inc. The remaining authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The authors report an Australian experience of lateral lumbar interbody fusion (LLIF) with respect to clinical outcomes, fusion rates, and complications, with recombinant human bone morphogenetic protein-2 (rhBMP-2) and other graft materials., Methods: Retrospective cohort study of LLIF patients 2011-2021. LLIFs performed lateral decubitus by four experienced surgeons past their learning curve. Graft materials classified rhBMP-2 or non-rhBMP-2. Patient-reported outcomes assessed by VAS, ODI, and SF-12 preoperatively and postoperatively. Fusion rates assessed by CT postoperatively at 6 and 12 months. Complications classified minor or major. Clinical outcomes and complications analysed and compared between rhBMP-2 and non-rhBMP-2 groups., Results: A cohort of 343 patients underwent 437 levels of LLIF. Mean age 67 ± 11 years (range 29-89) with a female preponderance (65%). Mean BMI 29kg/m 2 (18-56). Most common operated levels L3/4 (36%) and L4/5 (35%). VAS, ODI and SF-12 improved significantly from baseline. Total complication rate 15% (53/343) with minor 11% (39/343) and major 4% (14/343). Ten patients returned to OR (2-wound infection, 8-further instrumentation and decompression). Most patients (264, 77%) received rhBMP-2, the remainder a non-rhBMP-2 graft material. No significant differences between groups at baseline. No increase in minor or major complications in the rhBMP-2 group compared to the non-rhBMP-2 group respectively; (10.6% vs 13.9% [ p  = 0.42], 2.7% vs 8.9% [ p  < 0.01]). Fusion rates significantly higher in the rhBMP-2 group at 6 and 12 months (63% vs 40%, [ p  < 0.01], 92% vs 80%, [ p  < 0.02])., Conclusion: LLIF is a safe and efficacious procedure. rhBMP-2 in LLIF produced earlier and higher fusion rates compared to available non-rhBMP-2 graft substitutes.

Study Design: Retrospective cohort., Objective: To determine if performing a simultaneous laminectomy at an unfused level adjacent to an instrumented fusion increases the risk of adjacent segment disease (ASD)., Summary of Background Data: Laminectomy adjacent to instrumented fusion has uncertain outcomes. The increased mechanical forces at the unfused laminectomy may lead to more ASD. Few studies have examined the development of ASD with regard to laminectomy performed adjacent to instrumented fusions., Materials and Methods: Seven hundred eighty-nine patients underwent instrumented lumbar fusion and laminectomy at the same level(s) (n=676) or with an additional adjacent level laminectomy (n=113) with a minimum of 2-year follow-up. Diagnoses were degenerative spondylosis (n=241), degenerative spondylolisthesis (n=485), and isthmic spondylolisthesis (n=63) in addition to central stenosis. Primary outcome measures included development of ASD, time to development of ASD, revision surgery, and time to revision surgery., Results: The adjacent laminectomy group developed ASD at a significantly greater rate of 57.5% (n=65), compared with 35.2% (n=238) of the nonadjacent laminectomy group ( P <0.001). The revision surgery rate was also greater in the adjacent laminectomy group (22.1% vs. 13.5%, P <0.001). There was no difference in time to revision surgery (31.1 vs. 32.6 mo, P =0.71) or time to ASD development (31.2 vs. 32.3 mo, P =0.72). ODI and VAS scores did not differ, nor did patient baseline demographics including sex, BMI, Charleston Comorbidity Index, and tobacco use. The exception was the average age of the adjacent laminectomy group was 67.6 years while the average age of the nonadjacent laminectomy group was 62.3 years ( P <0.001). However, age was not found to be an independent predictor of ASD development ( P =0.44)., Conclusion: Surgeons should be cautious when performing a laminectomy adjacent to an instrumented fusion, as this increases the rate of ASD as well as revision surgery., Level of Evidence: Therapeutic Level-II., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: Stabilization of the occipitocervical (OC) junction with posterior instrumentation plays a vital role in addressing a spectrum of pathologies. Due to limited bone surfaces of the occiput and C1 lamina, achieving union across the OC junction is challenging., Purpose: To explore the biomechanics and a clinical series of patients treated with multirod constructs across the OC junction using a novel occipital plate with single- and dual-headed, modular tulip heads., Study Design/setting: Biomechanical analysis and retrospective case series., Patient Sample: Adults at a single institution who underwent posterior cervical multirod constructs across the OC junction., Outcome Measures: OC-C4 range of motion (ROM), maximum von Mises stress on the rods, and adjacent segment ROMs and intradiscal parameters. Patient demographics, revision operations, rod breakages, wound complications., Methods: A validated occiput-cervical finite element (FE) model was used to simulate OC-C4 cervical fixation under multidirectional pure moment loading. A total of 4 rod configurations were simulated: (A) 2-rod-Ti (4.0 mm titanium rods); (B) 2-rod-CoCr (3.5 mm cobalt chrome rods); (C) 3-rods (4.0 mm titanium rods); (D) 4-rods (4.0 mm titanium rods). The aforementioned measures were compared. A retrospective analysis was also performed of adults at a single institution who underwent posterior cervical multirod constructs across the OC junction., Results: Biomechanically, lowest primary rod stresses were observed for 3- and 4-rod constructs. Compared to 2-rod-Ti (121.8 MPa), 2-rod-CoCr showed a 43.2% stress increase in the rods, while 3- and 4-rods experienced rod stress reductions of 20% and 23.2%, respectively. No appreciable differences in OC-C4 ROM, C4-5 ROM, and C4-5 discal stresses were found between multirod and 2-rod constructs. Maximum occipital and C4 screw stresses were decreased in multirod constructs compared to 2-rods, with least stresses noted in the 4-rod construct. Maximum plate stresses were slightly increased in the 4-rod construct compared to 2- and 3-rod fixation, though the forces were largely similar among the constructs. Ten patients (average age 66.4±10.6 years; 8 males) were assessed clinically. Nine of the ten operations were for primary stabilization of pathological fractures and associated craniocervical and/or atlantoaxial instability using 4-rods across the OC junction. At an average follow-up time of 1.58±0.5 years (range, 1-2.3 years), there were no instrumentation failures, no adjacent segment failures, and no wound complications., Conclusions: In this proof-of-concept investigation, multiple rods (3- and 4-rods) across the OC junction using a novel occipital plate with single- and dual-headed, modular tulips was safe and effective in stabilizing the OC junction. Accompanying FE analysis demonstrated that multirod constructs decreased primary rod stresses and had lower stresses on occipital and C4 screws compared to 2-rod constructs, while occipital plate stresses were largely similar. Additional clinical studies are needed to confirm these findings and to determine the ultimate utility of multirod constructs across the OC junction., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background and Objectives: Appropriate correction relative to the age-adjusted sagittal alignment target reduces the proximal junctional failure (PJF) risk. Nonetheless, a considerable number of patients suffer from PJF despite optimal correction. The aim of this study was to identify the risk factors of PJF that occurs despite optimal correction relative to the sagittal age-adjusted score (SAAS) in adult spinal deformity surgery., Methods: Patients aged 60 years or older with adult spinal deformity who underwent ≥5-level fusion to the sacrum were initially screened. Among them, only patients who achieved optimal sagittal correction relative to the SAAS were included in the study. Optimal correction was defined as the SAAS point between -1 and +1. Various clinical and radiographic factors were compared between the PJF and no PJF groups and were further evaluated using multivariate analysis., Results: The final study cohort comprised 127 patients. The mean age was 67 years, and there were 111 women (87.4%). A mean of total fusion length was 7.2. PJF occurred in 42 patients (33.1%), while 85 patients (66.9%) did not develop PJF. Multivariate analysis showed that a high body mass index (odds ratio [OR] = 1.153, 95% CI = 1.027-1.295, P = .016), a higher lordosis distribution index (LDI) (OR = 1.024, 95% CI = 1.003-1.045, P = .022), and no use of hook fixation (OR = 9.708, 95% CI = 1.121-76.923, P = .032) were significant risk factors of PJF development. In the receiver operating characteristic curve analysis, the cutoff value for the LDI was calculated as 61.0% (area under the curve = 0.790, P < .001)., Conclusion: PJF developed in a considerable portion of patients despite optimal correction relative to the age-adjusted alignment. The risk factors of PJF in this patient group were high body mass index, high LDI exceeding 61%, and no use of hook fixation. PJF could be further decreased by properly managing these risk factors along with optimal sagittal correction., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Study Design: Retrospective study design., Objective: Evaluate correlations between preoperative expectations for pain improvement and 12-month functional outcomes and satisfaction following 1-2-level primary anterior cervical surgery., Summary of Background Data: Limited data exists evaluating correlations between patients' preoperative expectations for pain relief and subsequent functional and satisfaction outcomes following primary anterior cervical surgery. Understanding correlations between expectations and outcomes may help identify patients most likely to benefit from surgery., Materials and Methods: Patients who underwent 1-2-level primary anterior cervical discectomy and fusion (ACDF) or cervical disc arthroplasty for degenerative disease between 2016 and 2021 were included. All patients had 12-month Neck Disability Index (NDI) data. Preoperative expectations for pain relief were collected at the initial clinic visit using 5-point Likert scales. Preoperative and 12-month postoperative satisfaction were recorded using 7-point Likert scales. Covariates include age, sex, procedure type, smoking status, opioid use, worker's compensation/litigation, body mass index, and indication (radiculopathy vs. myelopathy). Linear regression models were constructed to assess the 12-month NDI change score versus pain relief expectations. Additional regression models assessed expectations versus achievement of minimum clinically important difference at 3 and 12 months and satisfaction at 12 months., Results: 198 ACDF (56.1% female, median age 57) and 52 CDR patients (55.8% female, median age 51) were included. Regression models found no significant correlations between pain relief expectations and degree of NDI score improvement at the 12-month postoperative timepoint or minimum clinically important difference achievement at the 3- and 12-month postoperative timepoints. There was no association between preoperative expectations and 12-month satisfaction. However, greater preoperative dissatisfaction was significantly associated with greater 12-month improvement in NDI score., Conclusion: Preoperative pain relief expectations were not associated with functional outcomes or satisfaction following 1-2 level primary ACDF or CDR at 12-month follow-up. Patients' dissatisfaction with their preoperative spinal condition was significantly associated with greater 12-month NDI improvement. Assessing preoperative satisfaction may help identify those most likely to benefit from surgery., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: The aim was to assess the clinical outcomes after posterior spinal fusion (PSF) in patients with Scheuermann's disease (SD)., Methods: SD undergoing PSF were retrospectively analyzed. Clinical outcome was determined using SRS-22- and Eq. 5D-questionaires preop and after 3, 12, 24 months after surgery. Whole spine x-rays were analyzed (preop, postop, after 6, 12, 24 months): sagittal and coronary Cobb angles, and pelvic parameters were evaluated; ideal lumbar lordosis (LL) was calculated using formula of le Huec (LL = 0.54*PI + 27.6). Surgical time, complications and blood loss were compared. Postop appearance of proximal (PJF) and distal junction failure (DJF) were calculated. Values were given as mean. Comparison with significance α = 0.05., Results: 73 patients were included. SRS-22 total score and EQ5D showed significant increase from preop to two-year FU (each p < 0.001). Preop Thoracic kyphosis (TK) was 75.1° with significant correction to 48.5° (p < 0.001). LL showed mean correction from 68.2° to 46.7° (p < 0.001). Difference between ideal and measured LL showed improvement from - 17.2° preop to -3.3° 6 month postop, good spontaneous correction of hyperlordosis. 63% had < 10° deviation from ideal LL 6 month postoperatively, whereas only 21.4% were in this range preoperatively. No significant changes for spinopelvic parameters during FU. Complications occurred in 13,7% of cases. A low revision rate for PJF (2,7%) was necessary. Subscore mental health showed a correlation to preop TK (p < 0.05)., Conclusion: Physiological reconstruction of sagittal alignment could be achieved in most cases (63%). Clinical FU results were convincing with significant improvement of patient's satisfaction. Complication rate was moderate and risk of PJF after PSF low., Competing Interests: Declarations. Ethics approval and consent to participate: The study was conducted according to the ethical principles suggested in the Declaration of Helsinki and informed consent was obtained from all participants and / or their legal guardian(s). The study was approved by the institutional review board of the Schoen- Clinic Neustadt. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Background: One-hole split endoscopy (OSE) is a novel endoscopic technique that offers some advantages in spinal surgery. However, without a clear understanding of the safe zone for OSE, surgeons risk injuring nerve roots during the procedure. This study aimed to measure the safe distances among critical bone markers, the intervertebral space and nerve roots between 1-degree degenerative lumbar spondylolisthesis (DLS) and non-DLS at the L 4/5 segment in patients via three-dimensional reconstruction and to compare the differences in relevant safety distances between the two groups. These findings provide a theoretical reference for the safe application of the OSE technique in transforaminal posterior lumbar interbody fusion (TPLIF)., Methods: The CT data of 56 patients were obtained, including 30 patients with 1-degree DLS at the L 4/5 segment (DLS group) and 26 patients with non-DLS (non-DLS group). The bone markers were determined in a three-dimensional model. The relevant distances were as follows: (1) Vertical distance (VD): inferior articular process tip (IAPT) to the upper margin of the intervertebral space (VD 1 ); superior articular process tip and the highest point of the mammillary process (HPMP) to the lower margin of the intervertebral space (VD 2 , VD 3 ). (2) Horizontal distance (HD): the lateral boundary to the medial boundary at the upper margin of the intervertebral space (HD 1 ) and at the lower margin of the intervertebral space (HD 2 ); the medial margin of the articular surface in the coronal position of the superior articular process to the medial boundary at the lower margin of the intervertebral space (HD 3 ); and the HPMP to the lateral boundary at the upper margin of the intervertebral space (HD 4 ) and at the lower margin of the intervertebral space (HD 5 )., Results: In the DLS group and non-DLS group, the VD 1 were (10.97 ± 2.15) mm and (11.32 ± 1.70) mm, the VD 2 were (11.06 ± 1.75) mm and (10.96 ± 0.91) mm, the VD 3 were (4.76 ± 1.54) mm and (5.01 ± 1.02) mm, the HD 1 were (10.54 ± 1.49) mm and (10.97 ± 1.06) mm, the HD 2 were (17.43 ± 2.01) mm and (17.32 ± 1.70) mm, and the HD 3 were (2.21 ± 0.99) mm and (2.11 ± 1.33) mm. These measurement distances were not significantly different between the two groups. While HD 4 (4.17 ± 1.41) mm in the DLS group was significantly greater than HD 4 (3.29 ± 1.78) mm in the non-DLS group, HD 5 (1.89 ± 0.93) mm in the DLS group was significantly lower than HD 5 (2.63 ± 1.45) mm in the non-DLS group (P < 0.05). There was no significant difference between VD 1 and VD 2 in the DLS group., Conclusion: Bone markers represent a novel positioning method for the treatment of 1-degree L 4/5 segmental DLS under OSE, which will aid in avoiding nerve root injury and provide a reference for the safety of TPLIF. If HPMP is used as an auxiliary bone marker for decompression of the L 4 exiting nerve root, HD 4 was greater and HD 5 was lower in the DLS group than in the non-DLS group during outwards fenestration and decompression. To improve safety, individualized imaging evaluation can be performed before the operation to select the appropriate grinding drill., Competing Interests: Declarations. Ethics approval and consent to participate: This study was performed in accordance with the principles of the Declaration of Helsinki. Approval was granted by the ethics committee of Binzhou Medical University Hospital, China [2022] No. (LW-34). All methods were performed in accordance with the relevant guidelines and regulations approved by the ethics committee of Binzhou Medical University Hospital. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Objectives: To analyze the risk factors for developing dysphagia after occipitocervical fusion (OCF) and investigate possible mechanisms and prognosis., Methods: The case data of 43 patients who underwent OCF were retrospectively reviewed. Patients were divided into group A (dysphagia group) and group B (non-dysphagia group) based on Bazaz scoring criteria. Baseline data and imaging parameters were collected: O-C2 angle, C2-7 angle, pharyngeal inlet angle (PIA), posterior occipital cervical angle (POCA), O-EA angle, Oc-Ax angle, Atlas-dens interval, C2-7 sagittal vertical axis (SVA), T1 slope, narrowest oropharyngeal airway space (nPAS), and thickness of the prevertebral soft tissue. Potential risk factors were identified via one-way intergroup comparisons and included in multivariable logistic regression analysis. Pearson or Spearman correlation analysis was performed to assess associations between dnPAS% and each parameter and inter-parameter correlations. Predictors were selected to plot receiver operating characteristic (ROC) curves for diagnostic evaluation. Prognosis was analyzed using the Kaplan-Meier method and curvilinear regression., Results: Dysphagia occurred in 17 of 43 patients (39.53%). By the final follow-up (≥ 12 months), 11 patients (25.58%) had residual symptoms. Baseline factors, including dyspnea (P = 0.028), operative segment (P = 0.021), operative time (P = 0.006), anesthesia time (P = 0.025), solitude (P = 0.019), and satisfaction (P < 0.001), differed significantly between groups. Imaging parameters dO-C2a (P < 0.001), dPOCA (P < 0.001), PoPIA (P = 0.036), dPIA (P < 0.001), dOc-Axa (P = 0.001), dC2-7 SVA (P = 0.040), PonPAS (P = 0.004), dnPAS (P = 0.005), and dnPAS% (P < 0.001) were also significantly different. Multivariable regression analysis identified dPIA (OR = 0.870, P = 0.008) as an independent protective factor. ROC analysis showed dPIA had good diagnostic value (AUC = 0.855) with a cutoff of -8°. Prognostic analysis indicated rapid recovery was possible by 3 months postoperatively, with full recovery achieved in ~ 30% of patients by 1 year, after which recovery plateaued., Conclusion: Postoperative dysphagia after OCF appears to result from multiple factors involving both "static + dynamic" elements. dPIA is a reliable predictor, with patients having a dPIA >-8° being less likely to develop dysphagia. However, only ~ 30% of patients achieve full recovery., Competing Interests: Declarations. Ethics approval and consent to participate: The study and all the medical records used in the study were approved by the Institutional Review Committee of The First Affiliated Hospital of Fujian Medical University, China. Informed consent was obtained from all patients who participated in this study. Written informed consent for publication was obtained from all participants. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Background: This study aimed to evaluate the efficacy and safety of long fusion versus short fusion in patients with degenerative scoliosis., Methods: Databases were systematically searched up to June 2024. The authors applied Review Manager 5.4 to manage the data and perform the analysis., Results: After the selection of 611 studies from electronic databases, 13 studies were eligible for inclusion. These 13 studies included 1261 patients: 534 patients underwent long fusion, and 727 underwent short fusion. At baseline, the Cobb angle, coronal imbalance, and sagittal imbalance were greater in the long fusion group. There was no difference in the VAS back, Cobb angle, ODI, hospital stay, revision surgery, adjacent segment degeneration, sacral slope, pelvic tilt, Cobb angle, lumbar lordosis, coronal balance, or sagittal balance at the final follow-up. The surgery time, complication rates, and amount of blood loss were greater in the long fusion group., Conclusions: Long fusion leads to superior radiographic improvement, particularly in reducing the Cobb angle and reconstructing coronal and sagittal balance. The long fusion group was inferior in terms of increased surgical time, more blood loss, and higher postoperative complication rates. At the final follow-up, there was no difference in the clinical or radiographic outcomes between the long and short groups. For patients with a large coronal Cobb angle and significant coronal or sagittal imbalance, long fusion surgery should be performed. On the other hand, for patients whose milder deformities and clinical symptoms are the main concern, short fusion surgery is recommended., Competing Interests: Declarations. Ethics approval and consent to participate: This study is based on publication, and there is no need for ethical approval. Consent for publication: All authors agree for publication. Competing interests: The authors declare that they have no competing interests., (© 2025. The Author(s).)

Background: Comparative studies of posterior lumbar interbody fusion with cortical bone trajectory and pedicle screw in older patients, particularly in those aged ≥ 80 years, are rare. This study aimed to retrospectively analyze the clinical and surgical outcomes following posterior lumbar interbody fusion with pedicle screw fixation compared to cortical bone trajectory in patients aged ≥ 80 years with degenerative lumbar spine disease., Methods: We included 68 patients aged ≥ 80 years who underwent degenerative lumbar spinal surgery at our spine center between January 2011 and December 2020. Of these 68 patients, 24 and 44 underwent posterior lumbar interbody fusion with cortical bone trajectory and pedicle screw, respectively., Results: The Visual Analog Scale for back pain was significantly lower in the cortical bone trajectory group than in the pedicle screw group at 6 months postoperatively (P = 0.049). The Oswestry Disability Index was significantly lower in the cortical bone trajectory group than in the pedicle screw group at 6 months postoperatively (P = 0.05). The estimated blood loss and operation time were significantly lower in the cortical bone trajectory group than in the pedicle screw group (P = 0.017 and P < 0.001, respectively). Postoperative morbidity was also lower in the cortical bone trajectory group (P = 0.049)., Conclusions: Despite these limitations, our study findings indicate that cortical bone trajectory is not inferior to posterior lumbar interbody fusion with pedicle screw fixation if there is a need for fusion in older patients aged ≥ 80 years., Competing Interests: Declarations. Ethics approval and consent to participate: The Institutional Review Board of National Health Insurance Service Ilsan Hospital approved this study (2022–01-027), and the requirement of informed consent was waived by the IRB staff Insoon Kim due to the retrospective nature of the study. This study was conducted in compliance with the IRB research guidelines of the National Health Insurance Service Ilsan Hospital. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Study Design: Retrospective observational cohort., Objectives: This study explores the impact of Intraoperative hypotension (IOH) on postoperative complications for major thoracolumbar spine fusion procedures., Summary of Background Data: IOH with mean arterial pressure (MAP) <65 mm Hg is associated with postoperative acute kidney injury (AKI) in general surgery. In spinal deformity surgery, IOH is a contributing factor to MEP changes and spinal cord dysfunction with deformity correction., Methods: A total of 539 thoracolumbar fusion cases, more than six surgical levels and >3 hours duration, were identified. Anesthetic/surgical data included OR time, fluid volume, blood loss, blood product replacement and use of vasopressors. Arterial-line based MAP data was collected at 1-minute intervals. Cummulative duration of MAP <65 mm Hg was recorded. IOH within the first hour of surgery vs. the entire case was determined. Post-op course and complications including SSI, GI complications, pulmonary complications, MI, DVT, PE, AKI, and encephalopathy were noted. Cumulative complications were grouped as none, one to two complications, or more than three complications., Results: There was a significant association between occurrence of complications and duration of IOH within the first hour of surgery (8.2 vs . 5.6 min, P <0.001) and across the entire procedure (28.1 vs . 19.3 min, P =0.008). This association persisted for individual major complications including SSI, acute respiratory failure, PE, ileus requiring NGT, and postoperative cognitive dysfunction. Comparison of patients with zero versus one to two versus three or more complications demonstrated that patients with three or more complications had a longer duration of IOH in the first hour of the surgery and that patients who had no complications received less vasopressor than patients who had one to two or three or more complications., Conclusion: This study identifies duration of IOH during the first hour of surgery as a previously unrecognized modifiable risk associated with major complications for multilevel lumbar fusion surgery., Level of Evidence: III., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Combining oblique lumbar interbody fusion (OLIF) with posterior pedicle screw fixation (PPSF) has been proposed to reduce cage subsidence, especially in osteoporotic spines. Recently, anterolateral screw-rod fixation has gained interest as it allows direct pathology observation and avoids a posterior approach. However, controversies exist between anterolateral screw fixation systems and traditional PPSF due to variations in osteoporotic vertebral mineral density, screw fixation positions, and fixation methods (bicortical vs. unicortical). This study aimed to investigate the biomechanical impact of fixation position and method in osteoporotic spine., Methods: Seventy-two fresh‑frozen porcine vertebrae (L1-6) were decalcified using 0.5 M EDTA and divided into two groups based on fixation method: bicortical or unicortical. Six groups for each method were created according to the screw position in the lateral vertebral body, with six specimens in each group: anterior, central, and posterior in the middle body and para-endplate regions. Correlations among screw position, fixation method and axial pullout strength were analyzed., Results: A 4-week decalcification process, bone mineral density in the porcine vertebrae decreased to approximately 48% (p < 0.05) of the original value, categorizing them as osteoporotic. Bicortical fixation showed significantly greater pullout forces than unicortical fixation, with differences ranging from 82 to 273%. Notably, central or posterior screws outperformed anterior screws in pullout strength., Conclusion: Bicortical fixation exhibited significantly greater pullout forces than unicortical fixation. We suggest positioning screws in the central or posterior region of the middle body with bicortical fixation in osteoporotic vertebrae., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Importance: The ability of surgeons to choose the right patient for fusion in addition to decompression when operating for degenerative spondylolisthesis with symptomatic spinal stenosis is debated. The addition of fusion increases risk, morbidity, and costs but has been claimed to give better results for selected patients., Objective: To investigate whether following surgeons' opinions regarding fusion was associated with clinical outcomes., Design, Setting, and Participants: This cohort study was conducted alongside the Norwegian Degenerative Spondylolisthesis and Spinal Stenosis randomized clinical trial, which showed noninferiority for decompression alone compared with decompression with fusion. From February 12, 2014, to December 18, 2017, trial surgeons from 16 Norwegian departments denoted their preferred treatment for 222 of 267 patients with symptomatic spinal stenosis and degenerative spondylolisthesis. For this analysis, the clinical outcomes of the patients who were and were not randomized to the recommended treatment were compared., Main Outcome and Measures: The primary outcome was a reduction of at least 30% from baseline to 2 years after surgery on the Oswestry Disability Index, ranging from 0 (no impairment) to 100 (maximum impairment). Secondary outcomes included the Zürich Claudication Questionnaire, leg and back pain scores, and the EuroQol 5-Dimension score., Results: Among 222 patients (155 [70%] female; mean [SD] age, 66.2 [7.7] years), decompression alone was recommended for 112 patients, of whom 59 received only decompression, and additional fusion for 110 patients, of whom 57 received fusion. At 2-year follow-up, 87 of 116 patients (75%) who received surgery in agreement with the surgeons' recommendations and 77 of 106 (73%) who received surgery in disagreement with the surgeons' recommendations reached the primary outcome (difference, 2.4 percentage points; 95% CI, -9.1 to 13.9 percentage points). All secondary outcomes were in the same direction as the primary outcome., Conclusions and Relevance: In this cohort study of 222 patients with degenerative spondylolisthesis who participated in a randomized clinical trial, surgeons' recommendations were not associated with better outcomes than a random allocation when deciding between decompression alone and decompression with instrumented fusion. The results suggest that surgeons performing degenerative spondylolisthesis surgery could rely safely on evidence of operating with decompression alone, despite the conflict of expert opinion.

Purpose: To assess and compare coronal alignment correction at 2 year follow-up in adult spinal deformity (ASD) patients treated with and without the kickstand rod (KSR) construct., Methods: ASD patients who underwent posterior spinal fusion at a single-center with a preoperative coronal vertical axis (CVA) ≥ 3 cm and a minimum of 2 year clinical and radiographic follow-up were identified. Patients were divided into two groups: those treated with a KSR and those who were not. Patients were propensity score-matched (PSM) controlling for preoperative CVA and instrumented levels to limit potential biases that my influence the magnitude of coronal correction., Results: One hundred sixteen patients were identified (KSR = 42, Control = 74). There were no statistically significant differences in patient characteristics (p > 0.05). At baseline, the control group presented with a greater LS curve (29.0 ± 19.6 vs. 21.5 ± 10.8, p = 0.0191) while the KSR group presented with a greater CVA (6.3 ± 3.6 vs. 4.5 ± 1.8, p = 0.0036). After 40 PSM pairs were generated, there were no statistically significant differences in baseline patient and radiographic characteristics. Within the matched cohorts, the KSR group demonstrated greater CVA correction at 1 year (4.7 ± 2.4 cm vs. 2.9 ± 2.2 cm, p = 0.0012) and 2 year follow-up (4.7 ± 2.6 cm vs. 3.1 ± 2.6 cm, p = 0.0020) resulting in less coronal malalignment one (1.5 ± 1.3 cm vs. 2.4 ± 1.6 cm, p = 0.0056) and 2 year follow-up (1.6 ± 1.0 vs. 2.5 ± 1.5 cm, p = 0.0110). No statistically significant differences in PROMs, asymptomatic mechanical complications, reoperations for non-mechanical complications were observed at 2 year follow-up. However, the KSR group experienced a lesser rate of mechanical complications requiring reoperations (7.1% vs. 24.3%. OR = 0.15 [0.03-0.72], p = 0.0174)., Conclusions: Patients treated with a KSR had a greater amount of coronal realignment at the 2 year follow-up time period and reported less mechanical complications requiring reoperation. However, 2 year patient-reported outcomes were similar between the two groups., Competing Interests: Declarations. Competing interests: Fthimnir Hassan, Anson Bautista, Justin Reyes, Varun Puvanesarajah, Josephine Coury, and Sarthak Mohanty have no relevant financial or non-financial interests to disclose. Lawrence G. Lenke has received grant support from AO Spine, International Spine Summit Group, Scoliosis Research Society, EOS Technology and Setting Scoliosis Straight Foundation as a study investigator. Ronald A. Lehman has received grant support from the Department of Defense as a study investigator. Zeeshan M. Sardar, Joseph M. Lombardi, Ronald A. Lehman, and Lawrence G. Lenke have received consulting fees from Medtronic. Lawrence G. Lenke has received consulting fees from Acuity Surgical and Abryx. Lawrence G. Lenke has received reimbursements from Broadwater, AO Spine, and Scoliosis Research Society for attending meetings/travel. Ronald A. Lehman and Lawrence G. Lenke have received royalties and are patent holders from Medtronic. Ronald A. Lehman has received royalties and is a patent holder from Stryker. Joseph M. Lombardi has received consulting fees from Stryker. Ethical approval: AAAR6015. This retrospective chart review study involving human participants was in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The Human Investigation Committee (IRB) of Columbia University Irving Medical Center approved this study. Informed consent: Informed consent was obtained from all individual participants included in the study., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)

Objective: To compare the clinical efficacy of unilateral biportal endoscopy technology (UBE) with anterior cervical discectomy and fusion(ACDF)for the treatment of single-segment cervical spondylotic radiculopathy (CSR)., Methods: Retrospective analysis of 60 patients with CSR, of which 30 were treated with ACDF (group A) and 30 were treated with UBE (group B). Cision length, operation time, intraoperative blood loss, hospitalization duration, postoperative complications preoperative and postoperative VAS, NDI scores, height and stability of the liability gap were compared between the two groups., Results: Compared with the A group, the incision length, duration and intraoperative blood loss were significantly less in the B group (P < 0.05), and the difference was statistically significant. As the postoperative time increased, the VAS score and NDI score decreased significantly in both groups (P < 0.05or < 0.01). However, the differences in VAS and NDI scores between the two groups at the corresponding time points were not statistically significant, and only the VAS score at 1 day postoperatively showed a more pronounced decrease in the B group, which was statistically significant compared with that in the A group. The difference in intervertebral space height and stability of the postoperative liability gap between the two groups at the final follow-up was not statistically significant when compared with the preoperative period. The incidence of postoperative complications in the two groups was smaller in the B group than in the A group, and the difference was not statistically significant., Conclusions: UBE can effectively treat patients with single-segment CRS and promote rapid recovery., Competing Interests: Declarations. Conflict of interest: The authors declare that they have no competing interests., (© 2024. The Author(s).)

Purpose: The primary objective of this study is to evaluate and compare the clinical and radiographic outcomes of the combined spinous process-splitting approach with a Wiltse (SPSW) approach, the combined conventional approach with a Wiltse (CW) approach, and the conventional open (CO) approach in unilateral transforaminal lumbar interbody fusion (TLIF)., Methods: The clinical outcomes were assessed, and intraoperative data and complications were collected. Numeric Rating Scale (NRS) scores for low back pain and leg pain, the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) scores for evaluating functions of the lumbar spine and health-related quality of life, and the modified MacNab standard for assessing satisfaction were analyzed. Radiographic outcomes included disc space height, segmental lordosis, interbody fusion assessment, and the rate of muscle atrophy of the multifidus and the erector spinae muscles., Results: Among the three groups, the SPSW group exhibited the shortest operation and drain retention time, lowest intraoperative blood loss, and minimal postoperative blood loss. Notably, the SPSW group displayed the highest level of social life function based on the JOABPEQ, and the highest level of patient satisfaction according to the modified MacNab Criteria, along with the lowest rate of muscle atrophy., Conclusion: All the SPSW, CW, and CO approach TLIF procedures achieved overall satisfactory effects of decompression and fusion for lumbar degenerative diseases. The SPSW approach procedure appears to be associated with the smallest surgical trauma and highest satisfaction because of reducing iatrogenic injury of the paraspinal muscles., Competing Interests: Declarations. Conflict of interest: The author(s) declared no potential conflicts of interest concerning this article’s research, authorship, or publication., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The bioactive glass-ceramic spacer (BGS)-7, a biosynthetic intervertebral fusion material introduced in 2014, has not been the subject of comparative clinical studies on anterior cervical discectomy and fusion (ACDF) surgery. This study, for the first time, aims to compare the radiological and clinical outcomes of the renewed BGS-7, released in 2019, with those of an allograft spacer. The comparison includes a finite element analysis of the biomechanical properties of each implant, adding a novel dimension to the research. We prospectively followed up on 29 patients who underwent ACDF using BGS-7 as the experimental group. To select a control group for comparison, 253 patients with level 1 ACDF with an allograft spacer between 2012 and 2022 were selected from our hospital. Using propensity score matching, 27 and 54 patients in the BGS-7 and allograft groups, respectively, were selected. The average subsidence length was 1.02 ± 1.44 mm per level in the BGS-7 group and 2.27 ± 2.25 mm per level in the allograft group. Subsidence was observed in 14 of 54 patients (25.9%) in the allograft group and one of 27 patients (3.7%) in the BGS-7 group (p = 0.016). In the allograft group, 16 of the 54 patients (29.6%) monitored for 6 months achieved satisfactory fusion outcomes with grades 4 and 5. Thirty-eight of 54 patients (70.4%) followed up for > 1 year in the allograft group achieved adequate fusion outcomes with grades 4 and 5. In the BGS-7 group, 17 of the 27 patients (63.0%) monitored for 6 months achieved satisfactory fusion results with grades 4 and 5. Twenty-three of the 27 patients (85.2%) followed up for > 1 year obtained adequate fusion outcomes with grades 4 and 5. There was a significant difference in the fusion rates between the two groups at 6 months (p = 0.008). BGS-7 is a reliable instrument for ACDF with no instances of instrumental failure. The BGS-7 group had positive clinical outcomes after surgery without any untoward events, and an early fusion rate with the creation of a bone bridge was noted during the 6-month follow-up period. Our findings not only indicate the safety of BGS-7 but also its practicality as a substitute for allografts in ACDF, instilling confidence in its application., (© 2024 Wiley Periodicals LLC.)

Background: The aim of our study is to establish whether the bone graft harvested and stored in the surgical wound by our novel technique is safe, reproducible and preserves the viability of the graft. In doing so, it promises successful bony fusion in spine and orthopaedic surgeries., Methods: A prospective clinical case series was conducted for autogenous bone graft storage in complex spine surgeries requiring staged procedures, in resource constrained settings. The bone graft harvested was morselized, wrapped in moist sterile gauze and stored in the paraspinal gutter within the operative site. Thereafter, the surgical wound was easily closed without tension. During the second stage surgery, the stored bone was retrieved and mixed with more autologous/allogenic bone (if necessary) and appropriately laid at fusion sites. Bacterial samples were sent before implantation., Results: 16 complex spinal deformity patients who underwent surgery in a resource constrained hospital over a period of 5 years were included. Duration between both stages was within 2 weeks. All patients showed successful fusion, with mean follow-up of 2.6 years. There were no cases of deep or systemic infection in our series. Surgeons found harvesting, storing and retrieval of graft to be straightforward., Conclusion: The operative site provides an ideal, safe and reproducible location for bone graft storage for staged surgeries conducted in resource constrained situations. The osteogenic potential of the autogenous bone graft is retained. This technique can be extrapolated to other orthopaedic surgeries conducted under resource limited environments like in surgical camps or combat medical facilities., Competing Interests: Declarations. Conflict of interests: There are no conflict of interests or financial disclosures to declare., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: This study aims to evaluate the accuracy and safety of C1 lateral mass and upper cervical pedicle screw placement assisted by the TiRobot II system., Methods: Ten patients who underwent cervical spine surgery assisted by the TiRobot II system were included. Screw accuracy was assessed using the Gertzbein-Robbins scale and by comparing the final screw positions with pre-planned trajectories. Deviations in screw tip, tail, and angle were recorded. Clinical data, including symptoms, surgical outcomes, and postoperative follow-up, were collected. Neurological improvement was evaluated using pre- and post-operative mJOA scores, with recovery rates calculated by Hirabayashi's method to assess outcomes 3 months after surgery., Results: A total of 30 screws were placed in 10 patients. All screws (30/30) were within the clinically acceptable range, with 93.33% (28 screws) classified as Grade A and 6.67% (2 screws) as Grade B. In the sagittal plane, the average tip deviation was 1.82 ± 0.79 mm, tail deviation 1.64 ± 0.60 mm, and angular deviation 1.92 ± 1.39°. In the axial plane, tip deviation was 1.96 ± 0.87 mm, tail deviation 1.92 ± 0.65 mm, and angular deviation 2.01 ± 1.07°. The average surgery time was 318.80 ± 66.07 min, with a mean EBL of 205.00 ± 55.03 mL. Postoperative mJOA scores significantly improved from 8.10 ± 1.97 to 12.60 ± 1.78 (p < 0.05), with a 52 ± 14% recovery rate. All patients showed significant symptom improvement., Conclusion: The TiRobot II system demonstrates the capability to precisely execute pre-planned trajectories and improves the accuracy and safety of C1 lateral mass and upper cervical screw placement., Competing Interests: Declarations. Conflict of interest: The authors declare that they have no competing interests. Ethical approval: This study was approved by the Ethics Committee of the First Affiliated Hospital of Sun Yat-sen University. This study was conducted according to the guidelines of the Declaration of Helsinki and approved by the hospital institutional review board (Ethics Approval Number 2020SYSUSH-001)., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To present two cases of life-threatening hemorrhage related to lumbar artery injury in adult spinal deformity (ASD) patients following S2‑alar‑iliac (S2AI) fixation and asymmetrical pedicle subtraction osteotomy (PSO), and discuss the possible reasons for postoperative hemorrhage in these patients., Methods: Patient A was a 52-year-old female with degenerative lumbar scoliosis who underwent posterior spinal fusion from T 8 -S 2 and one-level PSO at L 2 . Patient B was a 24-year-old male with severe kyphoscoliosis due to non-ambulatory cerebral palsy, who underwent posterior spinal fusion from T 3 -S 2 and one-level PSO at L 1 . Both patients underwent asymmetric PSO, where a larger wedge was resected from the convex side of the vertebral body rather than the concave side., Results: Both patients occurred a sudden increase in drainage within 3 h postoperatively, who were under anesthesia in AICU. Digital subtraction angiography (DSA) was emergently performed and revealed that the bleeding sites were from the lumbar artery, which was adherent to the convex side of the osteotomized vertebra in both cases. Then successful bleeding control was achieved through vascular embolization. Postoperative CT revealed spike formation at the anterior edges of the open wedge at the PSO level due to sagittal translation (ST), with noticeable derotation of the osteotomized vertebra., Conclusion: For patients with severe kyphoscoliosis, asymmetrical PSO increases the risk of lumbar artery injury on the convex side, and postoperative ST may further contribute to this risk. In cases where a sudden increase in drainage is observed postoperatively, it is crucial to consider the possibility of lumbar artery injury, particularly on the convex side of the osteotomized vertebra., Competing Interests: Declarations. Conflict of interest: The authors have no competing interests to declare that are relevant to the content of this article., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Sacroiliac joint (SIJ) dysfunction can occur as a result of injury, degeneration, or inflammation. This dysfunction presents symptoms of pain at various locations, including the low back, hips, buttocks, and legs. The diagnosis of SIJ dysfunction is challenging and cannot be achieved solely with imaging studies such as X-rays, MRI, or CT. The current gold standard diagnostic modality is intra-articular SIJ blocks using two differing local anesthetics. Current treatments for SIJ dysfunction may be beneficial for short-term relief but lack long-term efficacy. The purpose of our study was to examine the outcomes of patients who underwent minimally invasive, posterior SIJ fusion using allograft at a single center., Methods: This was a retrospective study which received exemption from the WCG IRB. Data regarding preoperative and postoperative pain levels, surgical time, complications, and medication usage were obtained retrospectively from patient electronic medical records and prescription drug monitoring program reports. No mapping was completed prior to the procedure. Pain was assessed with the 11-point (0-10) Visual Analogue Scale (VAS) and medication usage was assessed using Morphine Milligram Equivalents (MME). Patients were included if they had been diagnosed with SIJ dysfunction using two intra-articular diagnostic blocks that resulted in at least an 80% decrease in pain and had failed conservative management. Patients with sacral insufficiency fractures were excluded., Results: VAS scores reduced from 8.26 (SD = 1.09) at baseline to 2.59 (SD = 2.57), 2.55 (SD = 2.56), 2.71 (SD = 2.88), and 2.71 (SD = 2.88) at 3, 6, 9, and 12 months, respectively. MME reduced from 78.21 mg (SD = 51.33) to 58.95 mg (SD = 48.64), 57.61 mg (SD = 47.92), 61.71 mg (SD = 45.64), and 66.29 mg (SD = 51.65) at 3, 6, 9, and 12 months, respectively. All reductions in VAS scores and MME were statistically significant. No adverse events occurred, and the average operating room time was 40.16 min (SD = 6.27)., Conclusion: Minimally invasive, posterior SIJ fusion using allograft is a safe and efficacious method for managing SIJ dysfunction., (© 2024 World Institute of Pain.)

Study Design: Retrospective analysis of prospectively collected data., Objective: Evaluate the impact of prior cervical constructs on upper instrumented vertebrae (UIV) selection and postoperative outcomes among patients undergoing thoracolumbar deformity correction., Background: Surgical planning for adult spinal deformity (ASD) patients involves consideration of spinal alignment and existing fusion constructs., Methods: ASD patients with (ANTERIOR or POSTERIOR) and without (NONE) prior cervical fusion who underwent thoracolumbar fusion were included. Demographics, radiographic alignment, patient-reported outcome measures (PROMs), and complications were compared. Univariate and multivariate analyses were performed on POSTERIOR patients to identify parameters predictive of UIV choice and to evaluate postoperative outcomes impacted by UIV selection., Results: Among 542 patients, with 446 NONE, 72 ANTERIOR, and 24 POSTERIOR patients, mean age was 64.4 years and 432 (80%) were female. Cervical fusion patients had worse preoperative cervical and lumbosacral deformity, and PROMs ( P <0.05). In the POSTERIOR cohort, preoperative LIV was frequently below the cervicothoracic junction (54%) and uncommonly (13%) connected to the thoracolumbar UIV. Multivariate analyses revealed that higher preoperative cervical SVA (coeff=-0.22, 95% CI=-0.43 to -0.01, P =0.038) and C2SPi (coeff=-0.72, 95% CI=-1.36 to -0.07, P =0.031), and lower preoperative thoracic kyphosis (coeff=0.14, 95% CI=0.01-0.28, P =0.040) and thoracolumbar lordosis (coeff=0.22, 95% CI=0.10-0.33, P =0.001) were predictive of cranial UIV. Two-year postoperatively, cervical patients continued to have worse cervical deformity and PROMs ( P <0.05) but had comparable postoperative complications. Choice of thoracolumbar UIV below or above T6, as well as the number of unfused levels between constructs, did not affect patient outcomes., Conclusions: Among patients who underwent thoracolumbar deformity correction, prior cervical fusion was associated with more severe spinopelvic deformity and PROMs preoperatively. The choice of thoracolumbar UIV was strongly predicted by their baseline cervical and thoracolumbar alignment. Despite their poor preoperative condition, these patients still experienced significant improvements in their thoracolumbar alignment and PROMs after surgery, irrespective of UIV selection., Level of Evidence: IV., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To report on the failure rates of an expandable interbody spacer, used for spinal instrumented transforaminal lumbar interbody fusion (TLIF) or posterior thoracolumbar interbody fusion (PLIF)., Methods: In this retrospective, single-center observational cohort study we reviewed consecutive PLIF/TLIF patients using the Catalyft™ PL and PL40 expandable titanium interbody implant (Medtronic, Minneapolis (USA)) between 07/2022 and 11/2023. We recorded patient demographics, surgical parameters, adverse events, radiological parameters and clinical outcomes according to the MacNab criteria., Results: We identified 53 patients (mean age 68.6 ± 11.5 years; 49.1% female; mean BMI 25.7 ± 4.4 kg/m 2 ), in which 92 Catalyft™ spacers were implanted, mostly at L4/5 (n = 35; 38.0%) and L5/S1 (n = 31; 33.7%) for degenerative (n = 44; 83.0%), deformity (n = 7; 13.2%) or other indications (n = 2; 3.8%). We noticed secondary collapse of 20 (21.7%) spacers in 11 patients (20.7%) occurring after a mean time of 4.0 ± 4.1 months postoperatively. Age < 70 years was identified as risk factor for secondary collapse (OR 3.71, 95% CI 1.31-10.5, p = 0.014), but no association was found regarding other patient-specific or surgery-related variables. Pseudarthrosis was evident in seven patients (13.2%), of which four (7.6%) required revision surgery. Clinical outcome at last follow-up (mean 6.4 ± 4.2 months) was excellent/good in 29 (54.7%), fair in 14 (26.4%) and poor in six patients (11.3%)., Conclusion: We provide a critical analysis of our series of patients with use of a specific type of expandable interbody spacer. We noticed failure and secondary collapse in an unacceptably high number of implants, some of which required revision surgery., Competing Interests: Declarations. Conflict of interest: The authors report no conflicts of interest., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Posterior approach interbody fusion techniques such as posterior lumbar interbody fusion and transforaminal interbody fusion are known as the workhorse procedures for lumbar spinal fusion. Over the years, advancements in procedural steps, technique, and technology have sought to improve patient outcomes. Within the last 2 decades, considerable emphasis has been placed upon minimally invasive techniques utilizing tubular retractors and conscious sedation. Innovation in materials engineering, visualization technology such as endoscopes, and enabling technologies such as augmented reality and robotics have served to enhance the procedures and their outcomes., Competing Interests: Disclosure M P. Steinmetz receives royalties/honoraria from Globus, and speaker fees from Cerapedics. Authors A A. Patel, S. Srivatsa, and M A. Davison have no relevant disclosures., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Study Design: Retrospective cohort study., Purpose: The impact of neuromuscular disorders such as multiple sclerosis (MS) on outcomes following long segment fusion is underreported. This study evaluates the impact of MS on two-year (2Y) postoperative complications and revisions following ≥ 4-level fusion for adult spinal deformity (ASD)., Methods: Patients undergoing ≥ 4-level fusion for ASD were identified from a statewide database. Patients with a baseline diagnosis of MS were also identified. Patients with infectious/traumatic/neoplastic indications were excluded. Subjects were 1:1 propensity score-matched (MS to no-MS) based on age, sex and race and compared for rates of 2Y postoperative complications and reoperations. Logistic regression models were utilized to determine risk factors for adverse outcomes at 2Y., Results: 86 patients were included overall (n = 43 per group). Age, sex, and race were comparable between groups (p > 0.05). MS patients incurred higher charges for their surgical visit ($125,906 vs. $84,006, p = 0.007) with similar LOS (8.1 vs. 5.3 days, p > 0.05). MS patients experienced comparable rates of overall medical complications (30.1% vs. 25.6%) and surgical complications (34.9% vs. 30.2%); p > 0.05. MS patients had similar rates of 2Y revisions (16.3% vs. 9.3%, p = 0.333). MS was not associated with medical, surgical, or overall complications or revisions at minimum 2Y follow-up., Conclusion: Patients with MS experienced similar postoperative course compared to those without MS following ≥ 4-level fusion for ASD. This data supports the findings of multiple previously published case series' that long segment fusions for ASD can be performed relatively safely in patients with MS., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)

Purpose: This study aimed to explore associations between ABO blood type and postoperative adjacent segment degeneration/disease (ASD) following lumbar spine fusion, as well as evaluate differences in spinopelvic alignment, perioperative care, postoperative complications, and patient-reported outcome measures (PROMs)., Methods: An ambispective study was performed. Patients who underwent posterolateral or posterior lumbar interbody fusion were included. Demographic, perioperative and postoperative, clinical, and blood type information was recorded. Pre- and post-operative radiographic imaging was analyzed for alignment parameters and development of ASD., Results: 445 patients were included, representing O+ (36.0%), O- (5.2%), A+ (36.2%), A- (6.3%), B+ (12.1%), B- (1.6%), and AB+ (2.7%) blood types. Most patients were female (59.1%), and had a mean age of 60.3 years and BMI of 31.1 kg/m 2 . Postoperatively, groups did not differ in duration of the hospital (p = 0.732) or intensive care unit (p = 0.830) stay, discharge disposition (p = 0.504), reoperation rate (p = 0.192), or in-hospital complication rate (p = 0.377). Postoperative epidural hematoma was most common amongst A + patients (p = 0.024). Over a mean of 11.0 months of follow-up, all patients exhibited similar improvement in PROMs, with 132 (29.7%) patients developing radiographic evidence of ASD. B + patients were significantly more likely than A + and O + patients to develop spondylolisthesis and ASD (p < 0.05). No significant differences in sagittal alignment parameters and number of levels of fusion were found (p > 0.05)., Conclusions: This is the first large-scale study to address and demonstrate proof-of-principle that ABO blood type, a non-modifiable risk factor, is associated with ASD following lumbar spine fusion., Competing Interests: Declarations. Competing interests: The authors have no competing interests to disclose in relation to this work., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

To evaluate whether preoperative conversion from a gastrostomy tube (G-tube) to a gastrojejunostomy tube (GJ-tube) decreases short-term postoperative aspiration pneumonia and gastrointestinal complications in children with neuromuscular scoliosis. We conducted a retrospective chart review from January 2006 to October 2021 of pediatric patients who had neuromuscular scoliosis and were fed with a G-tube before spinal fusion. Eligible patients were divided into two groups based on whether they were converted to a GJ-tube preoperatively. Preoperative characteristics and 30-day postoperative outcomes were compared between groups using Chi-square tests. Of 261 eligible patients, 205 were converted to a GJ-tube, while 56 underwent spinal fusion with a G-tube. Common complications following G-tube to GJ-tube conversion were feeding intolerance (25.2%), GJ-tube malfunction (17.7%), and at least one episode of vomiting (17.4%). Within 30 days of discharge, 12.5% of GJ-tube patients and 11.5% of G-tube patients experienced aspiration pneumonia ( P  = 0.85). The GJ-tube group received postoperative tube feeds 7 hours earlier than the G-tube group on average (51.6 h vs. 44.5 h, P  = 0.02). Within 30 days of discharge, one (0.5%) patient from the GJ-tube group died of gastrointestinal complications unrelated to conversion and two (3.6%) patients in the G-tube group died from aspiration pneumonia ( P  = 0.12). Results suggest that there were no appreciable differences in outcomes between patients converted to a GJ-tube preoperatively compared to those who continued to use a G-tube. However, preoperative characteristics indicate that a higher number of complex patients were converted to a GJ-tube, indicating potential selection bias in this retrospective sample. Level of evidence: Level III., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Purpose: To assess the benefits of using the touched vertebra (TV) rule in Lenke classification for thoracic curves of adolescent idiopathic scoliosis (AIS)., Methods: A total of 141 AIS patients with thoracic curves determined by Suk classification were divided based on whether the lowest instrumented vertebra (LIV) matched the TV into groups of mTV (n = 84, LIV = TV), TV- (n = 21, LIV above TV), and TV+ (n = 36, LIV below TV) for 5-year follow-up. The radiological parameters were the central sacral vertical line (CSVL)-LIV distance, distal end vertebra rotation, coronal, and sagittal parameters. Complications included adding-on phenomenon, coronal imbalance, and distal junctional kyphosis., Results: Adding-on phenomenon and coronal imbalance were significantly higher in the TV- group (P = 0.006) and TV + group (P = 0.006), respectively. The distal motion segments were significantly saved in the mTV group (P < 0.001). The CSVL-LIV distance was significantly improved in the mTV group compared to the others during the 5-year follow-up (P = 0.007). The 5-year follow-up CSVL-LIV distance correlated with LIV tilt angle (r = 0.442, P = 0.021) and coronal balance (r = 0.437, P = 0.023)., Conclusions: Selecting the TV as LIV minimizes the loss of the distal mobile segment and reduces the complications in the thoracic curves of AIS, which produces a more stable LIV on the CSVL. Therefore, TV is an ideal landmark for determining the distal fusion level using the Lenke classification or Suk classification., Competing Interests: Declarations. Ethics approval and consent to participate: This retrospective study was approved by the Institutional Review Board of Sanggye Paik Hospital (IRB number: SGPAIK 2022-07-003), and informed written consent was waived due to the retrospective design. Consent for publication: The authors have obtained written informed consent from the patient to publish this case report and any accompanying images. Competing interests: The authors declare that they have no conflicts of interest., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: This study aims to perform a meta-analysis that integrates multiple literature sources to evaluate the clinical efficacy of oblique lumbar interbody fusion (OLIF) versus minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for treating lumbar degenerative diseases (LDD)., Methods: A systematic search was conducted across various databases, including CNKI, VIP, WANFANG DATA, SinoMed, PubMed, Cochrane Library, Embase, and Web of Science, for clinical comparative studies on OLIF and MIS-TLIF for treating LDD, covering the time frame from the inception of the databases to September 2024. Following PRISMA guidelines, studies were screened, assessed, and data were extracted rigorously. Indicators extracted included operative time, intraoperative blood loss, hospital stay, visual analog scale (VAS) scores, Oswestry Disability Index (ODI), disc height (DH), segmental lordotic angle (SLA), lumbar lordosis angle (LLA), postoperative JOA scores, patient satisfaction, complication rates, and fusion rates. Meta-analysis was performed using Review Manager 5.4 software., Results: A total of 24 studies were included, comprising 11 randomized controlled trials and 13 retrospective cohort studies. The total population consisted of 1785 patients, with 898 in the OLIF group and 887 in the MIS-TLIF group. The meta-analysis indicated that, compared to the MIS-TLIF group, the OLIF group exhibited significantly lower intraoperative blood loss, shorter hospital stays, improved postoperative DH, shorter operative time, reduced postoperative VAS scores, lower postoperative ODI scores, and improved postoperative SLA and LLA. No significant differences were observed between the groups in postoperative JOA scores, fusion rates, complication rates, or patient satisfaction. The OLIF group exhibited advantages such as lower blood loss, shorter hospital stays, higher postoperative fusion rates, and improved recovery of disc and foraminal heights., Conclusion: Compared to MIS-TLIF, OLIF is associated with a shorter operative time and less intraoperative blood loss, potentially leading to better relief of leg pain, restoration of DH, and prevention of subsidence. These findings offer valuable insights for clinical practice., Competing Interests: Declarations. Ethics approval and consent to participate: This meta-analysis uses data from published studies; therefore, ethical approval and individual consent to participate were not required. All included studies were conducted in accordance with ethical standards. Consent for publication: Not applicable, as this meta-analysis does not include individual patient data. Competing interests: The authors declare that they have no competing interests related to this study., (© 2024. The Author(s).)

Airway compromise due to prevertebral soft tissue swelling is a potentially devastating complication following anterior cervical discectomy and fusion (ACDF). However, there are no studies on the postoperative patient posture for enhancing airway patency after ACDF. This study aimed to analyze the effect of neck and mouth postures on airway patency following ACDF and to suggest the beneficial postoperative patient posture for improving airway patency. A retrospective review of 39 patients who underwent ACDF in C3 or C4 level was conducted. Airway diameter and prevertebral soft tissue thickness were measured in six different neck-mouth postures using lateral radiographs. The diameters of the airway and prevertebral soft tissues showed significant changes in relation to the neck postures and mouth openings after ACDF (P < 0.001). Regarding postures, neck extension with closed mouth posture showed significant wider airway diameter than that of the other postures (P < 0.001). Moreover, this posture showed the thinnest prevertebral soft tissues; however, it showed no significant difference compared to the neutral-closed and extension-open postures (P = 1.00 and P = 0.053). In conclusion, neck extension with a closed mouth significantly widened the airway diameter and reduced prevertebral soft tissue swelling, making it the best posture to maintain airway patency after ACDF., Competing Interests: Competing interests: The authors declare no competing interests. Ethical approval: The study was reviewed and approved by the institutional review board of Seoul National University Bundang Hospital (Approval Number: B-1707-409-106). The informed consent was waived due to the retrospective nature of the study by the institutional review board of Seoul National University Bundang Hospital. All methods were carried out by relevant guidelines and regulations., (© 2024. The Author(s).)

Objective: To explore clinical effect of percutaneous endoscopic posterolateral trans-facet lumbar interbody fusion (PE-PTLIF) in treating degenerative lumbar spondylolisthesis., Methods: The data of 38 patients with degenerative lumbar spondylolisthesis treated with PE-PTLIF from December 2019 to June 2021 were retrospectively analyzed, including 18 males and 20 females, aged from 39 to 75 years old with an average of (60.2±8.9) years old;1 patient with L 3,4 , 23 patients with L 4,5 , 14 patients with L 5 S 1 ;29 patients with degreeⅠand 9 patients with degreeⅡaccording to Meyerding grading. Operative time, intraoperative blood loss, drainage volume, postoperative hospital stay and complcations were observed, visual analogue scale (VAS) was used to evaluate degree of lumbar and leg pain before operation, 3 d and 3, 6 and 12 months after operation, respectively. Oswestry disability index (ODI) was used to evaluate degree of low back pain dysfunction before operation, 3, 6 and 12 months after operation. The modified MacNab standard was used to evaluate clinical efficacy at 12 months after operation. Dural sac cross-sectional area (DSCSA), intervertebral disc height (IDH), lumbar spondylolisthesis rate (SR), lumbar lordosis angle (LL) and segmental lordosis angle (SL) were compared before operation and 12 months after operation. Interbody fusion at 12 months was evaluated according to Bridwell intervertebral fusion standard., Results: All patients were followed up for 13 to 28 months with an average of (18.47±4.12) months. The operative time was (181.68±19.34) min, intraoperative blood loss was (152.87±57.03) ml, drainage volume was (48.18±11.43) ml, and postoperative hospital stay was (9.45±2.18) d and 3 patients occurred complications. VAS of lumbar pain before operation, 3 days, 3, 6 and 12 months after operation were (6.68±1.16), (4.32±1.13), (2.18±0.70), (1.89±0.56) and (1.57±0.72), respectively. VAS of leg pain were (6.24±1.42), (2.95±1.09), (1.76±0.71), (1.68±0.74) and (1.26±0.69) respectively. Preoperative and postoperative 3, 6 and 12 months of ODI were (63.21±11.21) %, (25.24±6.46) %, (20.97±6.26) % and (17.73±5.88) %, respectively. Postoperative VAS of lumbar and leg pain and ODI were significantly lower than those of preoperative time points ( P <0.05). According to the modified MacNab standard, 23 patients got excellent result, 10 good, 3 fair, and 2 poor at 12 months after operation. Postoperative DSCSA, IDH, SR, LL and SL at 12 months were (128.32±21.95) mm 2 , (11.19±1.66) mm, (4.44±2.19)%, (49.32±5.63)°, (9.16±1.90)°, respectively, and were improved compared with preoperative [(58.36±18.11) mm 2 , (8.19±2.06) mm (18.43±4.78) %, (42.38±4.94) ° and (8.06±2.06) °] ( P <0.05). Thirty-four patients obtained gradeⅠfusion, 3 patients woth gradⅡfusion and 1 patient with grade Ⅲ fusion at 12 months after operation according to Bridwell intervertebral fusion standard., Conclusion: PE-PTLIF could provide effective method for the treatment of gradeⅠand gradeⅡdegenerative lumbar spondylolisthesis. It has advantages of less bleeding, sufficient decompression, fast postoperative recovery and high fusion rate, which could effectively relieve lumbar and leg pain, restore vertebral space height and improve lumbar sagittal balance. PE-PTLIF is a safe and minimally invasive surgery.

Objective: To explore clinical effect of Zero-profile intervertebral fusion with cage-titanium plate in treating multilevel cervical spondylotic myelopathy., Methods: From January 2016 to January 2020, 107 patients with multisegmental cervical spondylotic myelopathy treated by surgery were retrospectively analyzed and divided into Hybrid group and control group according to different surgical methods. There were 54 patients in Hybrid group, including 42 males and 12 females, aged from 33 to 77 years old with an average of (57.3±9.5) years old;20 patients with C 3 -C 6 , 27 patients with C 4 -C 7 and 7 patients with C 3 -C 7 ;Zero-profile intervertebral fusion with cage-titanium plate internal fixation was performed. There were 53 patients in control group, including 34 males and 19 females;aged from 36 to 79 years old with an average of (57.8±8.9) years old;17 patients with C 3 -C 6 , 27 patients with C 4 -C 7 , and 9 patients with C 3 -C 7 ;titanium plate interbody fusion fixation was performed. Operation time, blood loss and complications between two groups were compared, visual analogue scale (VAS), Japanese Orthopedic Association (JOA) scores and neck disability index (NDI) were used to assess recovery of clinical symptoms;cervical lordosis (CL), cervical sagittal vertical axis (C-SVA), and T 1 slope (T 1 S) were measured and compared to evaluate cervical sagittal plane parameters., Results: All patients were followed up, Hybrid group was followed up for 24 to 64 months with an average of (31.7±18.4) months, and control group was followed up for 24 to 65 months with an average of (32.6±15.8) months. There was no significant difference in follow-up time between two groups ( P >0.05). Operation time and blood loss in Hybrid group were less than those in control group ( P <0.05). VAS, JOA score and NDI were significantly improved between two groups at the lastest follow-up ( P <0.05). There were no significant difference in VAS, JOA and NDI scores between two groups before and after operation ( P >0.05). CL in both two groups at 3 months and the latest follow-up after operation were significantly improved than those before operation ( P <0.05), there were no significant difference between two groups in T1S and C-SVA before and after operation ( P >0.05). Postoperative dysphagia occurred in 2 patients in Hybrid group and 9 patients in control group, and had statistically difference in the incidence of dysphagia between two groups ( χ 2 =5.112, P =0.024). During the follow-up, there were no complications such as loosening, displacement or fracture of internal fixation between two groups., Conclusion: Compared with titanium plate interbody fusion, Zero-profile intervertebral fusion combined with cage-titanium plate for the treatment of multilevel cervical spondylotic myelopathy could shorten surgical time and blood loss, reduce surgical trauma and postoperative swallowing difficulties, and is conducive to early and rapid recovery.

Objective: To explore characteristics, management strategies and preventive measures of fusion device displacement after oblique lateral interbody fusion (OLIF) in treating lumbar lesions., Methods: The clinical data of 12 patients with fusion device displacement after OLIF for lumbar lesions in 4 medical centers from October 2014 to December 2018 were retrospectively analyzed, including 4 males and 8 females, aged from 53 to 81 years old;2 patients with lumbar disc degeneration, 4 patients with lumbar spinal stenosis, 3 patients with lumbar degenerative spondylolisthesis and 3 patients with lumbar degenerative kyphosis;preoperative dual-energy X-ray bone mineral density (BMD) was detected in 1 patient with T-value > -1 SD, 5 patients with T-value >-1~-2.5 SD, and 6 patients with T-value <-2.5 SD;9 patients with single-segment fusion, 1 patient with 2-segment fusion, and 2 patients with 3-segment fusion;standalone OLIF was performed in 9 patients and OLIF combined with posterior pedicle screws in 3 patients. Visual analogue scale (VAS) and Oswestry disability index (ODI) were used to evaluate low back pain and lumbar function recovery at the time of fusion graft displacement and at the latest follow-up, respectively. In addition, according to imaging results during follow-up, the fusion device subsidence or redisplacement, loosening or fracture of internal fixation, and interbody fusion were observed, and the changes in the height of interbody space on the segment with fusion device displacement were measured and compared., Results: There were no necrosis or infection in skin incision of 10 patients after reoperation, and 12 patients were followed up for 12 to 48 months. VAS for low back pain decreased from 3 to 8 points at the time of fusion device displacement to 0 to 2 points at the latest follow-up. ODI recovered from 31% to 51% at the time of fusion transfer to 5% to 13% at the latest follow-up. There was no loosening or fracture of the pedicle screw system during follow-up. All 11 patients with bone grafting with fusion apparatus had fusion apparatus subsidence and no further displacement of fusion apparatus. The vertebral space height recovered from 9.0 to 12.7 mm at the time of fusion graft displacement to 8.0 to 11.8 mm at the latest follow-up. Interbody fusion was obtained in all patients except 1 with no imaging results at the latest follow-up., Conclusion: OLIF could be used for fusion of lumbar lesions, and there is a risk of fusion organ displacement after operation, especially in cases of bone loss or osteoporosis before surgery, end-plate injury during surgery, and Stand-alone mode, and most of them occur within 3 months after operation. Surgery is required for the transposition of the fusion apparatus in the Stand-alone OLIF mode during the primary operation. Although good clinical results could be obtained by timely detection and accurate treatment, it is still necessary to emphasize the precise selection of cases before operation, the appropriate application of OLIF, and precise operation during operation to prevent displacement of fusion device.

Background and Objectives: Spine surgery has undergone significant advancements, particularly with regard to robotic systems that enhance surgical techniques and improve patient outcomes. As these technologies become increasingly integrated into surgical practice, it is essential to evaluate their added value and cost savings. Hence, this study compared robot-assisted and navigation-based spine surgery, focusing on surgical efficiency. Materials and Methods: We conducted a single-center, retrospective cohort study of patients undergoing single- and double-level transforaminal lumbar interbody fusion (TLIF) and oblique lumbar interbody fusion (OLIF) surgeries. Patients were divided into two groups: those who had robot-assisted and navigation-based surgeries, stratified by surgery type (TLIF or OLIF) and fusion levels (one or two). A comparative analysis of factors related to surgical efficiency, including operative duration, blood loss, and length of hospital stay, was conducted. Results: Our results showed a statistically significant reduction in operative duration for robot-assisted one- and two-level OLIF cases, with average time savings of 50 and 62 min, respectively, compared to navigation-based surgery. These time savings translated to an estimated cost reduction of SGD 1500 for the hospital for each patient for a two-level OLIF procedure and could be higher as the number of operated levels increase. Conclusions: These results indicated that robot-assisted spine surgery offers superior surgical efficiency and cost savings, particularly with increased numbers of surgical levels. As robotic technologies evolve, their integration into spine surgery is justified, promising improved patient outcomes and cost-effectiveness.

Background: Degenerative lumbar spondylolisthesis (DLS) with lumbar spinal stenosis (LSS) is a common condition resulting in substantial lower back pain and disability. Surgical intervention is recommended only when conservative treatment fails. This study compared UBE-TLIF and MIS-TLIF regarding clinical outcomes and fusion rates in patients with single-segment DLS with LSS., Methods: A total of 85 patients who underwent either UBE-TLIF (n = 40) or MIS-TLIF (n = 45) were examined retrospectively. Clinical results were evaluated by the Visual Analog Scale (VAS) for pain and the Oswestry Disability Index (ODI) for functional outcomes. Radiographs and CT were utilized to assess radiological outcomes such as disc height (DH), lumbar lordosis (LL), and interbody fusion rates. The two groups were also compared in terms of perioperative data (operation time, blood loss, hospital stay, and fluoroscopy exposure)., Results: Both surgical techniques showed similar statistically significant improvements in VAS and ODI scores. Fusion rates at 2 years postoperatively were identical, including 95% for the UBE-TLIF group and 97.7% for the MIS-TLIF group. However, compared with MIS-TLIF, the operative time and fluoroscopy exposure were longer for UBE-TLIF, but intraoperative blood loss and length of hospital stay were reduced., Conclusions: UBE-TLIF and MIS-TLIF can successfully treat single-segment DLS in the presence of LSS, achieving similar clinical and radiological outcomes with low complication rates. Although UBE-TLIF has certain advantages regarding perioperative outcomes (less blood loss and shorter hospital stay), MIS-TLIF is associated with shorter operative times and lower fluoroscopy exposure., Competing Interests: Declarations. Ethical approval: The study was approved by the Ethics Committee of Yan’an Hospital affiliated to Kunming Medical University, Kunming, Yunnan, P.R. China, under approval number 2024-193-01. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Purpose: To investigate the association between intravenous methylprednisolone administration and the risk of surgical site infection (SSI) following posterior lumbar fusion (PLF) surgery., Methods: This retrospective, single-center study analyzed data from 800 adult patients who underwent elective PLF surgery at our institution. Patients were classified according to postoperative intravenous methylprednisolone administration. Univariate and multivariable logistic regression, and subgroup analysis were used to assess the association between methylprednisolone administration and SSI risk, as well as its impact on postoperative pain management., Results: Our analysis showed no significant association between intravenous methylprednisolone administration and the development of a SSI after PLF. Subgroup analyses suggested that methylprednisolone was potentially protective in patients with a body mass index (BMI) < 25 kg/m 2 . In addition, patients treated with methylprednisolone had significantly lower pain scores in the early postoperative period, and lower incidence of postoperative nausea and vomiting (PONV) compared to patients not treated with methylprednisolone. However, there was no significant difference in pain scores between the 2 groups at 4 weeks postoperatively., Conclusions: This study suggests that intravenous methylprednisolone administration may not increase the risk of SSI after single-level PLF. In addition, it appears to have a beneficial effect on postoperative pain management and PONV, especially during the early recovery phase., Competing Interests: Declarations. Ethical approval and consent to participate: This study was approved by the Ethics Committee of the First Affiliated Hospital of Sun Yat-sen University. Written informed consent was obtained from all participants. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Objective: To develop a nomogram model for the prediction of the risk of prolonged length of hospital stay (LOS) in spinal fusion patients., Methods: A retrospective cohort study was carried out on 6272 patients who had undergone spinal fusion surgery. Least absolute shrinkage and selection operator (LASSO) regression was performed on the training sets to screen variables, and the importance of independent variables was ranked via random forest. In addition, various independent variables were used in the construction of models 1 and 2. A receiver operating characteristic curve was used to evaluate the models' predictive performance. We employed Delong tests to compare the area under the curve (AUC) of the different models. Assessment of the models' capability to improve classification efficiency was achieved using continuous net reclassification improvement (NRI) and integrated discrimination improvement (IDI). The Hosmer-Lemeshow method and calibration curve was utilised to assess the calibration degree, and decision curve to evaluate its clinical practicality. A bootstrap technique that involved 10 cross-validations and was performed 10,000 times was used to conduct internal and external validation. The were outcomes of the model exhibited in a nomogram graphics. The developed nomogram was validated both internally and externally., Results: Model 1 was identified as the optimal model. The risk factors for prolonged LOS comprised blood transfusion, operation type, use of tranexamic acid (TXA), diabetes, electrolyte disturbance, body mass index (BMI), surgical procedure performed, the number of preoperative diagnoses and operative time. The diagnostic performance of the nomogram model was satisfactory, with AUC values of 0.784 and 0.795 for the internal and external validation sets, respectively. Model discrimination was favourable in both the internal (C-statistic, 0.811) and external (C-statistic, 0.814) validation sets. Calibration curve and Hosmer-Lemeshow test showed acceptable agreement between predicted and actual results. The decision curve shows that the model provides net clinical benefit within a certain decision threshold range., Conclusions: This study developed and validated a nomogram to identify the risk of prolonged LOS in spinal fusion patients, which may help clinicians to identify high-risk groups at an early stage. Predictors identified included blood transfusion, operation type, use of TXA, diabetes, electrolyte disturbance, BMI, surgical procedure performed, number of preoperative diagnoses and operative time., Competing Interests: Declarations. Ethics approval and consent to participate: The study protocol was approved by the Ethics Committee of Liuzhou Worker’s Hospital (ethics number: KY2024569) and adhered to the Declaration of Helsinki’s (2013) guidelines. All patients are exempt from written informed consent. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: The aim of our study was to explore the effect of local corticosteroids on dysphagia in patients undergoing anterior cervical discectomy and fusion (ACDF). To address a gap in the limited research on this topic, we utilized high-resolution impedance manometry (HRIM) and the Eating Assessment Tool-10 (EAT-10) questionnaire to assess the effects on key swallowing muscles, including the upper esophageal sphincter (UES)., Methods: We randomly assigned patients undergoing ACDF to either the corticosteroid group or the saline solution group. Patients received 10 mg of local triamcinolone or saline solution prevertebrally at the cervical spine level before wound closure. Swallowing function preoperatively and at 1 month postoperatively were compared between the groups with use of HRIM parameters (e.g., UES relaxation, UES opening extent, intrabolus pressure, and pharyngeal contraction) and EAT-10 scores. Patients were also followed for postoperative complications and mortality within 12 months after surgery., Results: Thirty patients completed the study. The median age was 55 years in the corticosteroid group and 57 years in the saline group, and each group had 8 female patients. All participants were Taiwanese. We found no significant difference in median preoperative UES relaxation pressure between the corticosteroid and saline solution groups (33.8 and 31.3 mm Hg, respectively; p = 0.54). Postoperatively, the corticosteroid group had significantly lower median UES relaxation pressure than the saline solution group (24.5 versus 33.6 mm Hg; p = 0.01). Before and after surgery, all other HRIM parameters and EAT-10 scores were similar between the groups, with the corticosteroid group demonstrating median pre- and postoperative EAT-10 scores of 0 and 4, respectively, and the saline solution group demonstrating scores of 2 and 3, respectively. There were no adverse events., Conclusions: The findings suggest that local corticosteroids may reduce UES relaxation pressure at 1 month after ACDF, potentially enhancing UES opening. Further research is required to verify our findings., Level of Evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: This study was funded by National Taiwan University Hospital (110-32). The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/I247 )., (Copyright © 2024 The Author(s). Published by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Our understanding of the relationship between sagittal alignment and mechanical complications is evolving. In normal spines, the L1-pelvic angle (L1PA) accounts for the magnitude and distribution of lordosis and is strongly associated with pelvic incidence (PI), and the T4-pelvic angle (T4PA) is within 4° of the L1PA. We aimed to examine the clinical implications of realignment to a normal L1PA and T4-L1PA mismatch., Methods: A prospective multicenter adult spinal deformity registry was queried for patients who underwent fixation from the T1-T5 region to the sacrum and had 2-year radiographic follow-up. Normal sagittal alignment was defined as previously described for normal spines: L1PA = PI × 0.5 - 21°, and T4-L1PA mismatch = 0°. Mechanical failure was defined as severe proximal junctional kyphosis (PJK), displaced rod fracture, or reoperation for junctional failure, pseudarthrosis, or rod fracture within 2 years. Multivariable nonlinear logistic regression was used to define target ranges for L1PA and T4-L1PA mismatch that minimized the risk of mechanical failure. The relationship between changes in T4PA and changes in global sagittal alignment according to the C2-pelvic angle (C2PA) was determined using linear regression. Lastly, multivariable regression was used to assess associations between initial postoperative C2PA and patient-reported outcomes at 1 year, adjusting for preoperative scores and age., Results: The median age of the 247 included patients was 64 years (interquartile range, 57 to 69 years), and 202 (82%) were female. Deviation from a normal L1PA or T4-L1PA mismatch in either direction was associated with a significantly higher risk of mechanical failure, independent of age. Risk was minimized with an L1PA of PI × 0.5 - (19° ± 2°) and T4-L1PA mismatch between -3° and +1°. Changes in T4PA and in C2PA at the time of final follow-up were strongly associated (r 2 = 0.96). Higher postoperative C2PA was independently associated with more disability, more pain, and worse self-image at 1 year., Conclusions: We defined sagittal alignment targets using L1PA (relative to PI) and the T4-L1PA mismatch, which are both directly modifiable during surgery. In patients undergoing long fusion to the sacrum, realignment based on these targets may lead to fewer mechanical failures., Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The International Spine Study Group (ISSG) is funded through research grants from NuVasive, SI-Bone, DePuy Synthes Spine, K2M, Stryker, Biomet, AlloSource, and Orthofix, and individual donations. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/I191 )., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Objective: The purpose was to analyze how rod characteristics, screw density and cages influence the incidence of mechanical complications compared to patient-related factors and alignment in adult spinal deformity instrumented T9-T11 to pelvis., Methods: Register data of 302 patients was analyzed. Relative lumbar lordosis (RLL) and relative sagittal alignment (RSA) was measured. Surgical data included rod characteristics, pedicle screw density and interbody cages. Univariate and multivariate logistic regression models were used., Results: Pseudarthrosis occurred in 24.1%. On univariate analysis Odds Ratio (OR) was 0.74 for ≥ 3 cages (p = 0.452), 0.48 for 4 rods (p = 0.008), 4.30 for high screw density (p = 0.001). Patient-related factors were non-significant. Multivariate OR was 0.59 for 4 rods (p = 0.084) and 4.67 for high screw density (p = 0.005). PJK/PJF occurred in 19.2%. Age > 60 had an OR 2.83 (p = 0.023), postoperative RSA malaligned OR 2.84 (p = 0.030), severely malaligned OR 6.54 (p < 0.001). Implant characteristics were non-significant. Multivariate OR was 1.26 for age > 60 (p = 0.657), 2.32 for malaligned RSA (p = 0.097), 5.69 for severely malaligned RSA (p = 0.001). Screw loosening occurred in 8.9%. Univariate OR was 0.95 for ≥ 3 cages (p = 0.920), 1.64 for 4 rods (p = 0.235), 0.25 for high screw density 1.5-2 (p = 0.011). Patient-related factors were non-significant. Multivariate OR for high screw density was 0.23 (p = 0.022)., Conclusion: Four rods decrease the pseudarthrosis risk. Cages have a secondary role. High screw density doesn't prevent from pseudarthrosis. Postoperative malalignment is the main PJK/PJF risk factor. Age plays a secondary role. Implant characteristics have a minor influence. High screw density constructs have a lower risk for screw loosening., Level of Evidence: 3-Retrospective register study., Competing Interests: Declarations. Conflict of interest: Yann Philippe Charles is consultant for Stryker, Clariance, Spinevision and Ceraver; he received research support from Medtronic and Philips. Ethics approval: Institutional review board approval was obtained at each site., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To describe single-index-level fusion surgery using a cervical pedicle screw (CPS) after the complete facet resection of spinal dumbbell tumors and to compare it with partial facet resection without fusion., Methods: We retrospectively reviewed patients who underwent surgery for dumbbell-shaped cervical spine tumors. They were categorized into the fused group (complete facet resection with fusion using CPS) and the unfused group (partial facet resection without fusion). We compared demographics, tumor characteristics, resection rates (gross total, subtotal, or partial), and regrowth rates between the groups. Complete facet resection was performed for maximal tumor removal. In the fused group, single-index-level fusion was achieved using CPS. Despite tumor-associated erosion of the index vertebra's pedicle and/or lateral mass, the CPS was directly inserted into the vertebral body through an imaginary virtual pedicle without a lateral mass or pedicle purchase., Results: A total of 34 patients underwent surgery for dumbbell-shaped cervical tumors; half were classified into each group. There were no significant differences in demographic or tumor characteristics, including Asazuma classification, or histological diagnosis (P > 0.05). However, the gross total resection rate was significantly higher in the fused group (16/17, 94.1% vs. 9/17, 52.9%; P value = 0.011). Tumor recurrence was observed in 3 (17.6%) patients in the unfused group; no recurrence (0%) occurred in the fused group., Conclusions: Complete facet resection with fusion using CPS significantly increased the gross total tumor removal rate, compared with partial resection without fusion. Therefore, CPS improved fusion surgery for maximal motion preservation, resulting in single-level fusion surgery., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are common complications observed after adult spinal deformity (ASD) surgery and major cause for unplanned reoperations. In addition to spinal alignment, osteoporosis and paraspinal muscle (PSM) degeneration are reportedly indispensable factors that account for PJK/PJF., Purpose: To investigate the utility of the preoperative risk assessment model using MRI-based skeletomuscular metrics in predicting PJK and/or PJF(PJK/PJF) after ASD correction., Study Design: Retrospective case-control study., Patient Sample: Consecutive series of 149 patients at a single academic institution., Outcome Measures: MRI-based measurements of vertebral bone quality at upper instrumented vertebra (VBQ-U) score and fat infiltration rate (FI%) of paraspinal muscle (PSM)., Methods: We performed a retrospective analysis of patients with ASD who underwent ≥5-segment fusion. The vertebral bone quality (VBQ) scoring system was used to assess the bone quality. The PSM quality including FI% and cross-sectional area (CSA) was evaluated. Multivariate logistic regression was performed to determine potential risk factors of PJK/PJF., Results: Of 149 patients who underwent ASD surgery, PJK/PJF was found in 45(30.2%). Mean VBQ-U scores were 3.45±0.64 and 3.00±0.56 for patients with and without PJK/PJF (p<.001). Mean FI% of PSM (L3/L4) was 27.9±12.8 and 20.7±13.3 for patients with and without PJK/PJF (p<.001). On multivariate analysis, the VBQ-U score and FI% of PSM were significant independent predictors of PJK/PJF. The AUC for the novel risk assessment model is 0.806, with a predictive accuracy of 86.7%., Conclusion: In patients undergoing ASD correction, paraspinal muscle and vertebral bone quality significantly outweigh radiographic alignment parameters in predicting PJK/PJF. The MRI-based risk assessment model offers a valuable tool for early assessing individualized risk for PJK/PJF., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Study Design: A retrospective cohort study., Objective: To evaluate the mid-term effect of intervertebral disc degeneration (DD) in patients with adolescent idiopathic scoliosis (AIS) who underwent pedicle screw instrumentation (PSI) and rod derotation (RD) with direct vertebral rotation (DVR)., Summary of Background Data: Posterior spinal fusion is a mainstay of surgical treatment in AIS, and DVR is considered a main corrective maneuver for vertebral rotation. However, the mid-term effect of intervertebral DD after DVR is still unknown in AIS., Methods: A total of 336 vertebrae for 48 patients with AIS who underwent PSI and RD with DVR were retrospectively assessed for intervertebral DD. They were divided into two groups based upon intervertebral DD, defined as Pfirmann grade more than IV. The Pfirrmann grade and modic change were evaluated at the disc above the uppermost instrumented vertebra (UIV), the disc below the lowest instrumented vertebra (LIV), and the lumbar disc levels., Results: With the 11.6 years of mean follow-up, 41.7% (20/48) of patients exhibited DD, while modic changes were observed in 4.2% (2/48) of the included patients. The discs below the LIV, L4-5, and L5-S1 were significantly shown to have an increasing trend of Pfirmann grade. The preoperative thoracic kyphosis was significantly lower in the DD group (22.0°) than in the non-DD group (31.4°) ( P = 0.025) and negatively correlated with DD ( r = -0.482, P = 0.018). The Pfirrmann grade of L5-S1 showed a high level of correlation with DD ( r = 0.604, P < 0.001)., Conclusions: The degenerative change at the disc below the LIV, L4-5, and L5-S1 levels was observed following PSI and RD with DVR. Thoracic hypokyphosis may negatively influence intervertebral discs in patients with AIS required for deformity correction. Therefore, the restoration of thoracic kyphosis is important to prevent long-term DD in AIS., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To investigate the impact of preoperative compensatory curve on the postoperative curve progression in congenital scoliosis (CS) patients following thoracolumbar hemivertebra (HV) resection and short fusion., Methods: This study retrospectively reviewed a consecutive cohort of patients with CS who underwent thoracolumbar HV resection and short fusion with a minimum of 2 years follow-up. According to the preoperative curve pattern, patients were divided into compensatory curve group non-compensatory curve group. Based on the postoperative coronal curve evolution, patients were further divided into the progressed group (Group P, with curve decompensation ≥ 20°) and the non-progressed group (Group NP, characterized by well-compensated curves)., Results: A total of 127 patients were included in this study, with 31 patients in the compensatory curve group and 96 patients in the non-compensatory curve group. The incidence of postoperative coronal curve progression was significantly higher in the compensatory curve group than that in non-compensatory curve group (35.5% vs. 13.5%, p = 0.007). In the compensatory curve group, patients who experienced postoperative curve progression showed fewer fusion segments (p = 0.001), greater preoperative UIV translation (p = 0.006), greater preoperative LIV tilt (p = 0.017), and larger postoperative UIV tilt (p < 0.001) compared with patients in group NP. Multiple logistic regression demonstrated that the shorter fusion segments and greater postoperative UIV tilt were two independent risk factors for postoperative curve progression., Conclusion: The presence of the compensatory curve was associated with a higher incidence of postoperative curve progression in patients with CS who underwent thoracolumbar HV resection and short fusion. Shorter fusion segments and greater postoperative UIV tilt were found to be the risk factors for postoperative curve progression., Competing Interests: Declarations. Grant & financial support: This work was supported by the National Natural Science Foundation of China (NSFC) (No. 82302781), fundings for Clinical Trials from the Affiliated Drum Tower Hospital, Medical School of Nanjing University, and the Jiangsu Provincial Key Medical Center. Conflict of interest: The authors declare that they have no conflict of interest with respect to this manuscript., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background Context: Failure to fuse following anterior cervical discectomy and fusion (ACDF) may result in symptomatic pseudoarthrosis. Traditional diagnosis involves computerized tomography to detect bridging bone and/or flexion-extension radiographs to assess whether segmental motion is above specific thresholds; however, there are currently no well-validated diagnostic tests. We propose a biomechanically rational approach to achieve a reliable diagnostic test for pseudoarthrosis., Purpose: Develop and test a biomechanically based approach to the diagnosis of pseudoarthrosis., Study Design: Literature review, development of theory, reanalysis of a previously published study with surgical exploration as the gold-standard, and retrospective analysis of pooled studies to understand time to fusion., Methods: Fully automated methods were used to measure disc space strains (change in disc space height divided by initial height). Measurement error combined with the reported failure strain of trabecular bone led to a proposed strain threshold for diagnosis of pseudoarthrosis following ACDF. We reanalyzed previously reported flexion-extension radiographs for asymptomatic volunteers to assess whether flexion-extension radiographs, in the absence of fusion surgery, can be expected to provide sufficient stress on motion segments to allow for reliable strain-based fusion assessment. The sensitivity and specificity of strain- and rotation-based pseudoarthrosis diagnosis were assessed by reanalysis of previously reported post-ACDF flexion-extension radiographs, where intraoperative fusion assessments were also available. Finally, we assessed changes in strain over time using 9,869 flexion-extension radiographs obtained 6 weeks to 84 months post-ACDF surgery from 1,369 patients., Results: The estimated error in automated measurement of disc space strain from radiographs was approximately 3%, and the reported failure strain of bridging bone was less than 2.5%. On that basis, we propose a 5% strain threshold for pseudoarthrosis diagnosis. Reanalysis of a study in which intraoperative fusion assessments were available revealed 67% sensitivity and 82% specificity for strain-based diagnosis of pseudoarthrosis, which was comparable to rotation-based diagnosis. Analysis of post-ACDF flexion-extension radiographs revealed rapid strain reduction for up to 24 months, followed by a slower decrease for up to 84 months. When rotation is less than 2°, the strain-based diagnosis differed from the rotation-based diagnosis in approximately 14% of the cases., Conclusions: We propose steps for standardizing diagnosis of pseudoarthrosis based on the failure strain of bone, measurement error, and retrospective data. These steps include obtaining high-quality flexion-extension studies, the application of proposed diagnostic thresholds, and the use of image stabilization for conclusive diagnosis, when motion is near thresholds. The necessity for an accurate diagnosis with minimal radiation exposure underscores the need for further optimization and standardization in diagnosing pseudoarthrosis following ACDF surgery., Clinical Significance: In a symptomatic postspine fusion patient, it is important to diagnose or rule-out pseudoarthrosis. There are currently no well-validated diagnostic tests for this condition. Incorporating strain-based intervertebral motion analysis into the diagnosis could lead to a standardized and validated test for detecting spine pseudoarthrosis., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Understanding the mechanism and extent of preoperative deformity in revision procedures may provide data to prevent future failures in lumbar spinal fusion patients., Methods: ASD patients without prior spine surgery (PRIMARY) and with prior short (SHORT) and long (LONG) fusions were included. SHORT patients were stratified into modes of failure: implant, junctional, malalignment, and neurologic. Baseline demographics, spinopelvic alignment, offset from alignment targets, and patient-reported outcome measures (PROMs) were compared across PRIMARY and SHORT cohorts. Segmental lordosis analyses, assessing under-, match, or over-correction to segmental and global lordosis targets, were performed by SRS-Schwab coronal curve type and construct length., Results: Among 785 patients, 430 (55%) were PRIMARY and 355 (45%) were revisions. Revision procedures included 181 (23%) LONG and 174 (22%) SHORT corrections. SHORT modes of failure included 27% implant, 40% junctional, 73% malalignment, and/or 28% neurologic. SHORT patients were older, frailer, and had worse baseline deformity (PT, PI-LL, SVA) and PROMs (NRS, ODI, VR-12, SRS-22) compared to primary patients (p < 0.001). Segmental lordosis analysis identified 93%, 88%, and 62% undercorrected patients at LL, L1-L4, and L4-S1, respectively. SHORT patients more often underwent 3-column osteotomies (30% vs. 12%, p < 0.001) and had higher ISSG Surgical Invasiveness Score (87.8 vs. 78.3, p = 0.006)., Conclusions: Nearly half of adult spinal deformity surgeries were revision fusions. Revision short fusions were associated with sagittal malalignment, often due to undercorrection of segmental lordosis goals, and frequently required more invasive procedures. Further initiatives to optimize alignment in lumbar fusions are needed to avoid costly and invasive deformity corrections., Level of Evidence: IV: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding., Competing Interests: Declarations. Conflicts of interest: The authors declare that they have no conflicts of interest related to this paper., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Biportal endoscopic spinal surgery has become increasingly popular, and indications have expanded. Among these, biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) has yielded good results. Herein, we compared the clinical and radiological outcomes of 155 patients treated with BE-TLIF and open posterior lumbar interbody fusion (PLIF) for single-level lumbar degenerative diseases. Clinical outcomes included the visual analog scale for the back (VAS-back) and leg (VAS-leg), Oswestry Disability Index, and EuroQol 5-Dimensions. Radiological parameters and fusion rates were evaluated, and postoperative complications were recorded. In this cohort 68 and 87 patients were treated with BE-TLIF and PLIF, respectively. Both groups showed significant improvements in all clinical parameters compared with baseline, but BE-TLIF exhibited a more significant improvement in VAS-back at 1 and 6 months postoperatively. There were no significant differences in the radiological parameters or fusion rates. BE-TLIF had a significantly longer operation time, whereas PLIF exhibited a significantly higher estimated blood loss and surgical drainage, but no significant differences in postoperative complications. Compared to PLIF, BE-TLIF showed similarly good clinical and radiologic outcomes, with better results in terms of early postoperative outcomes. Thus, BE-TLIF is a viable alternative to PLIF with less back pain at 1 and 6 months postoperatively., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Institutional Review Board of the Hallym University Kangnam Sacred Heart Hospital (no. 2023-06-026). Exemption from informed consent was provided by the Institutional Review Board of Hallym University Kangnam Sacred Heart Hospital. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)