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Study Design: A retrospective cross-sectional study.Objective: To assess the association between spinal muscle morphology and spinopelvic parameters in lumbar fusion patients, with a special emphasis on lumbar lordosis (LL).Summary Of Background Data: Maintenance of sagittal alignment relies on muscle forces, but the basic association between spinal muscles and spinopelvic parameters is poorly understood.Materials and Methods: Patients operated between 2014 and 2017 who had both lumbar magnetic resonance imaging scan and standing whole-spine radiographs within six months before surgery were included. Muscle measurements were conducted on axial T2-weighted magnetic resonance images at the superior endplate L3-L5 for the psoas and L3-S1 for combined multifidus and erector spinae (paraspinal) muscles. A pixel intensity threshold method was used to calculate the total cross-sectional area (TCSA) and the functional cross-sectional area (FCSA). Spinopelvic parameters were measured on lateral standing whole-spine radiographs and included LL, pelvic incidence (PI), PI-LL mismatch, pelvic tilt, sacral slope, thoracic kyphosis, and sagittal vertical axis. Analyses were stratified by biological sex. Multivariable linear regression analyses with adjustments for age and body mass index (BMI) were performed.Results: A total of 104 patients (62.5% female) were included in the analysis. The patient population was 90.4% White with a median age at surgery of 69 years and a median BMI of 27.8 kg/m 2 . All muscle measurements were significantly smaller in women. PI, pelvic tilt, and thoracic kyphosis were significantly greater in women. PI-LL mismatch was 6.1° (10.6°) in men and 10.2° (13.5°) in women ( P =0.106), and sagittal vertical axis was 45.3 (40.8) mm in men and 35.7 (40.8) mm in women ( P =0.251). After adjusting for age and BMI, paraspinal TCSA at L3-L5, and paraspinal FCSA at L4 showed significant positive associations with LL in women. In men, psoas TCSA at L5 and psoas FCSA at L5 showed significant negative associations with LL, but none of the paraspinal muscle measurements.Conclusion: Our findings indicate that psoas and lumbar spine extensor muscles interact differently on LL among men and women, creating a unique mechanical environment.Level Of Evidence: Level 4. [ABSTRACT FROM AUTHOR]

Study Design: This was a preclinical study.Objective: Evaluate sex-dependent differences in the bone healing response to recombinant human bone morphogenetic protein-2 (rhBMP-2) in a rat posterolateral spinal fusion model.Summary Of Background Data: Minimal and conflicting data exist concerning potential sex-dependent differences in rhBMP-2-mediated bone regeneration in the context of spinal fusion.Materials and Methods: Forty-eight female and male Sprague-Dawley rats (N=24/group), underwent L4-L5 posterolateral fusion with bilateral placement of an absorbable collagen sponge, each loaded with 5 µg of bone morphogenetic protein-2 (10 µg/animal). At eight weeks postoperative, 10 specimens of each sex were tested in flexion-extension with quantification of range of motion and stiffness. The remaining specimens were evaluated for new bone growth and successful fusion via radiography, blinded manual palpation and microcomputed tomography (microCT). Laboratory microCT quantified bone microarchitecture, and synchrotron microCT examined bone microstructure at the 1 µm level.Results: Manual palpation scores differed significantly between sexes, with mean fusion scores of 2.4±0.4 in females versus 3.1±0.6 in males ( P <0.001). Biomechanical stiffness did not differ between sexes, but range of motion was significantly greater and more variable for females versus males (3.7±5.6° vs. 0.27±0.15°, P <0.005, respectively). Laboratory microCT showed significantly smaller volumes of fusion masses in females versus males (262±87 vs. 732±238 mm 3 , respectively, P <0.001) but significantly higher bone volume fraction (0.27±0.08 vs. 0.12±0.05, respectively, P <0.001). Mean trabecular thickness was not different, but trabecular number was significantly greater in females (3.1±0.5 vs. 1.5±0.4 mm -1 , respectively, P <0.001). Synchrotron microCT showed fine bone structures developing in both sexes at the eight-week time point.Conclusions: This study demonstrates sex-dependent differences in bone regeneration induced by rhBMP-2. Further investigation is needed to uncover the extent of and mechanisms underlying these sex differences, particularly at different doses of rhBMP-2. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective cohort.Objective: To determine if intraoperative on-table lumbar lordosis (LL) and segmental lordosis (SL) coincide with perioperative change in lordosis.Summary Of Background Data: Improvements in sagittal alignment are believed to correlate with improvements in clinical outcomes. Thus, it is important to establish whether intraoperative radiographs predict postoperative improvements in LL or SL.Materials and Methods: Electronic medical records were reviewed for patients ≥18 years old who underwent single-level and two-level anterior lumbar interbody fusion with posterior instrumentation between 2016 and 2020. LL, SL, and the lordosis distribution index were compared between preoperative, intraoperative, and postoperative radiographs using paired t tests. A linear regression determined the effect of subsidence on SL and LL.Results: A total of 118 patients met inclusion criteria. Of those, 75 patients had one-level fusions and 43 had a two-level fusion. LL significantly increased following on-table positioning [delta (Δ): 5.7°, P <0.001]. However, LL significantly decreased between the intraoperative to postoperative radiographs at two to six weeks (Δ: -3.4°, P =0.001), while no change was identified between the intraoperative and more than three-month postoperative radiographs (Δ: -1.6°, P =0.143). SL was found to significantly increase from the preoperative to intraoperative radiographs (Δ: 10.9°, P <0.001), but it subsequently decreased at the two to six weeks follow up (Δ: -2.7, P <0.001) and at the final follow up (Δ: -4.1, P <0.001). On linear regression, cage subsidence/allograft resorption was predictive of the Δ SL (β=0.55; 95% confidence interval: 0.16-0.94; P =0.006), but not LL (β=0.10; 95% confidence interval: -0.44 to 0.65; P =0.708).Conclusion: Early postoperative radiographs may not accurately reflect the improvement in LL seen on intraoperative radiographic imaging, but they are predictive of long-term lumbar sagittal alignment. Each millimeter of cage subsidence or allograft resorption reduces SL by 0.55°, but subsidence does not significantly affect LL.Levels Of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective radiological analysis.Objective: To demonstrate the radiological outcome after a modified anterior column realignment (mACR) with partial anterior longitudinal ligament (ALL) release in oblique lateral interbody fusion (OLIF).Summary Of Background Data: Anterior column realignment (ACR) remains a powerful sagittal correction technique in minimally invasive adult spinal deformity surgery and is often combined with posterior column osteotomy (PCO) to achieve more lordosis. OLIF is ideal for ACR because the anterior-to-psoas corridor typically involves the anterolateral half of the disk.Methods: This study included 112 operated disk levels of 101 consecutive patients who underwent OLIF between L2-L3 and L4-L5 using a 12° lateral cage. The mACR was performed at 73 (65.2%) levels with 30% to 50% sectioning of the ALL. Each operated level was grouped according to the mACR and additional PCO as: (1) no mACR, OLIF only (n=39); (2) mACR with no PCO (n=18); (3) mACR with grade 1 PCO (n=27); (4) mACR with grade 2 PCO (n=22); or (5) mACR with grade 3 PCO (n=6).Results: At the last follow-up, the mean disk lordotic angles were 10.9±2.9°, 12.6±3.0°, 13.3±3.9°, 16.7±3.2°, and 16.8±2.4° in the no mACR, mACR with no PCO, mACR with grade 1 PCO, mACR with grade 2 PCO, and mACR with grade 3 PCO groups, respectively ( P <0.001). The mean increases in disk lordotic angle were 5.8±4.1°, 12.1±6.1°, 13.5±8.7°, 15.8±6.7°, and 17.9±6.2° in each group, respectively ( P <0.001).Conclusions: ACR can be performed with partial ALL release under direct vision in OLIF without deep dissection into the ventral disk space. The mACR in OLIF is a simple, safe, and effective technique for anterior column lengthening.Level Of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective cohort study.Objective: The aim was to investigate whether findings on magnetic resonance imaging (MRI) can be proxies (MRIPs) for segmental instability in patients with degenerative lumbar spinal stenosis (LSS) and/or degenerative spondylolisthesis (LDS) L4/L5.Background: LDS has a heterogeneous nature. Some patients have a dynamic component of segmental instability associated with LDS. Studies have shown that MRI can show signs of instability.Methods: Patients with LSS or LDS at L4/L5 undergoing decompressive surgery±fusion from 2010 to 2017, with preoperative standing lateral spine radiographs and supine lumbar MRI and enrolled in Danish national spine surgical database, DaneSpine. Instability defined as slip of >3 mm on radiographs. Patients divided into two groups based upon presence of instability. Outcome measures: radiograph: sagittal slip (mm). MRIPs for instability: sagittal slip >3 mm, facet joint angle (°), facet joint effusion (mm), disk height index (%), and presence of vacuum phenomena. Optimal thresholds for MRIPs was determined by receiver operating characteristic (ROC) curves and area under the curve (AUC). Logistic regression to investigate association between instability and MRIPs.Results: Two hundred thirty-two patients: 47 stable group and 185 unstable group. The two groups were comparable with regard to baseline patient-reported outcome measures. Thresholds for MRIPs: bilateral facet joint angle ≥46°; bilateral facet effusion ≥1.5 mm and disk height index ≥13%. Logistic regression showed statistically significant association with MRIPs except vacuum phenomena, ROC curve AUC of 0.951. By absence of slip on MRI logistic regression showed statistically significant association between instability on radiograph and the remaining MRIPs, ROC curve AUC 0.757.Conclusion: Presence of MRIPs for instability showed statistically significant association with instability and excellent ability to predict instability on standing radiograph in LSS and LDS patients. Even in the absence of slip on MRI the MRIPs had a good ability to discriminate presence of instability. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective cohort comparison study.Objective: To compare perioperative outcomes, radiographic parameters, and patient-reported outcome measures (PROMs) between minimally invasive unilateral laminotomy with bilateral decompression (MIS-ULBD) versus MIS transforaminal lumbar interbody fusion (MIS-TLIF) for treatment of low-grade lumbar degenerative spondylolisthesis.Summary Of Background Data: While lumbar degenerative spondylolisthesis is a common condition, optimal surgical treatment remains controversial. Newer MIS techniques, which preserve bone, paraspinal musculature, and posterior midline stabilizers, are thought to reduce the risk of iatrogenic instability and may obviate the need for fusion. However, few comparative studies of MIS techniques for low-grade lumbar degenerative spondylolisthesis currently exist.Materials and Methods: Consecutive patients with low-grade (Meyerding grade I or II) lumbar degenerative spondylolisthesis treated with single-level MIS-ULBD or MIS-TLIF were identified retrospectively from a prospectively collected spine surgery registry from April 2017 to November 2021. Perioperative outcomes, radiographic data, and PROMs were assessed.Results: A total of 188 patients underwent either MIS-ULBD or MIS-TLIF (79 MIS-ULBD and 109 MIS-TLIF). Patients who underwent MIS-ULBD tended to be older, had higher Charlson Comorbidity Index, lower mean percentage back pain, higher percentage of L4/L5 pathology, shorter operative time, lower estimated blood loss, and lower postoperative pain ( P <0.05). In both groups, there were statistically significant improvements at one year for five of the six PROMs studied: Oswestry Disability Index (ODI), visual analog scale (VAS)-back pain, VAS-leg pain, Short Form 12 Physical Component Score (SF12-PCS), and Patient-Reported Outcomes Measurement Information System (PROMIS) ( P <0.05). On multivariate analysis controlling for confounders, there were no associations between procedure type and achieving minimal clinically important difference at one year in any of the PROMs studied.Conclusions: The current study suggests that both MIS-ULBD and MIS-TLIF result in significant improvements in pain and physical function for patients with low-grade lumbar degenerative spondylolisthesis.Level Of Evidences: 3. [ABSTRACT FROM AUTHOR]

Study Design: A multicenter retrospective analysis.Objective: This study aims to investigate reoperation of misplaced pedicle screws (MPSs) after posterior spinal fusion (PSF), focusing on neurological complications.Summary Of Background Data: The management strategy for MPSs and the clinical results after reoperation are poorly defined.Materials and Methods: Subjects were 10,754 patients (73,777 pedicle screws) who underwent PSF at 11 hospitals over 15 years. The total number of reoperations for MPS and patient clinical data were obtained from medical records at each hospital.Results: The rate of reoperation for screw misplacement per screw was 0.17%. A total of 69 patients (mean age, 67.4±16.5 yr) underwent reoperation because of 82 MPS. Reasons for reoperation were neurological symptoms (58 patients), contact with vessels (5), suboptimal bone purchase (4), and misplacement recognized during operation (2). Neurological symptoms were the major reason for reoperation in cervical (5/5 screws, 100%) and lumbo-sacral (60/67 screws, 89.6%) regions. Contact with vessels was the major reason for reoperation in the thoracic spine (6/10 screws, 60.0%). We further evaluated 60 MPSs in the lumbo-sacrum necessitating reoperation because of neurological symptoms. The majority of MPSs necessitating reoperation were placed in the lower lumbar spine (43/60 screws, 71.7%). The mean pedicle breach tended to be larger in the incomplete recovery group than in the complete recovery group (6.8±2.4 vs . 5.9±2.2 mm, P =0.146), and the cutoff value resulting in incomplete resolution was 5.0 mm. Multivariate analysis revealed that medial-caudal breaches ( vs . medial breach, odds ratio: 25.8, 95% confidence interval: 2.58-258, P =0.0057) and sensory and motor disturbances ( vs . sensory only, odds ratio: 8.57, 95% confidence interval: 1.30-56.6, P =0.026) were significant factors for incomplete resolution of neurological symptoms.Conclusions: After reoperation, 70.1% of the patients achieved complete resolution of neurological symptoms. Factors associated with residual neurological symptoms included sensory and motor disturbance, medial-caudal breach, and larger pedicle breach (>5 mm). [ABSTRACT FROM AUTHOR]

Study Design: Single-center, multisurgeon, retrospective review.Objective: To evaluate the timing of return to commonly performed activities following minimally invasive spine surgery. Identify preoperative factors associated with these outcomes.Summary Of Background Data: Studies have reported return to activities with open techniques, but the precise timing of when patients return to these activities after minimally invasive surgery remains uncertain.Materials and Methods: Patients who underwent either minimally invasive lumbar laminectomy (MI-L) or minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) were included. Patient-reported outcome measures, return to drive, return to work, and discontinuation of opioids data were reviewed. Regression was conducted to identify factors associated with return to driving by 15 days, return to work by 30 days, and for discontinuing opioids by 15 days. A composite group analysis was also performed for patients who returned to all three activities by 30 days.Results: In total, 123 MI-L patients and 107 MI-TLIF patients were included. Overall, 88.8% of MI-L patients and 96.4% of MI-TLIF patients returned to driving in 11 and 18.5 days, respectively. In all, 91.9% of MI-L patients and 85.7% of MI-TLIF patients returned to work in 14 and 25 days. In all, 88.7% of MI-L patients and 92.6% of MI-TLIF patients discontinued opioids in a median of seven and 11 days. Overall, 96.2% of MI-L patients and 100% of MI-TLIF patients returned to all three activities, with a median of 27 and 31 days, respectively. Male sex [odds ratio (OR)=3.57] and preoperative 12-Item Short Form Physical Component Score (OR=1.08) are associated with return to driving by 15 days. Male sex (OR=3.23) and preoperative 12-Item Short Form Physical Component Score (OR=1.07) are associated with return to work by 30 days. Preoperative Visual Analog Scale back was associated with decreased odds of discontinuing opioids by 15 days (OR=0.84).Conclusion: Most patients return to activity following MI-L and MI-TLIF. These findings serve as an important compass for preoperative counseling. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective review.Objective: The objective of this study was to determine whether fusing to touched vertebra (TV) on prone x-rays (XRs) with minimal rotation (Gd 0/1) allow for shorter fusion with optimal correction.Summary Of Background: Previous studies have shown risk of "adding on" when TV is not selected as lowest instrumented vertebra (LIV). Fusion proximal to TV leads to suboptimal results but fusing to TV on standing XRs can result in longer fusions. On lying down XRs, TV moves proximally, and its rotation decreases by a grade.Methods: TV patients with minimal rotation were selected on prone (TVP) or standing XRs (TVS). Patients fused to rotated (Gd 2+) TV on standing or prone XRs were considered touched vertebra rotated (TVR). In the non-TV (NTV) group, LIV was fused proximal to TV. Disk wedging ≥5° determined risk of "adding-on." To compare patients fused to minimally rotated TV, to those that were not, patients in group A (TVP + TVS) were compared with group B (TVR + NTV).In part II: TVP, TVS, TVR, and NTV patients were compared. Subanalysis compared levels saved as the difference between predicted and real LIV in TVP and TVS patients. Another subanalysis was carried out for Lenke 1+2 and Lenke 3, 4, 5.In part III: XRs of nonoperative adolescents idiopathic scoliosis patients with Cobb <30 and Risser 4/5 were analyzed to determine "acceptable" end vertebra tilt and disc wedging and served as controls.Results: There were a significantly greater number of patients in group B patients(TVR + NTV) with final disk wedging ≥5°, final LIV translation ≥1 and ≥2 cm ( P <0.001).Utilizing prone XRs in TVP saved average 1 level, and 1.2 levels in TVS patients. TVP patients also had similar LIV tilt, disk wedging and coronal balance( P >0.05) to controls.Conclusion: Choosing minimally rotated (Gd 0/1) TV on prone XR saves levels without sacrificing radiographic outcomes. [ABSTRACT FROM AUTHOR]

Keywords: endoscopic discectomy; PTED; microdiscectomy; meta-analysis EN endoscopic discectomy PTED microdiscectomy meta-analysis E591 E594 4 09/01/22 20220915 NES 220915 Percutaneous transforaminal endoscopic discectomy (PTED) was intended as a less invasive surgical technique to treat sciatica caused by a lumbar disk herniation. References 1 Barber SM, Nakhla J, Konakondla S. Outcomes of endoscopic discectomy compared with open microdiscectomy and tubular microdiscectomy for lumbar disc herniations: a meta-analysis. Based on the current systematic review and meta-analysis, PTED can be considered a technique with equivalent effectiveness compared to microdiscectomy, with some moderate clinical advantages over microdiscectomy. [Extracted from the article]

Study Design: Retrospective cohort.Objective: To compare robotics and navigation for minimally invasive elective lumbar fusion in terms of radiation exposure and time demand.Summary Of Background Data: Although various studies have been conducted to demonstrate the benefits of both navigation and robotics over fluoroscopy in terms of radiation exposure, literature is lacking in studies comparing robotics versus navigation.Materials and Methods: Patients who underwent elective one-level or two-level minimally invasive transforaminal lumbar interbody fusion (TLIF) by a single surgeon using navigation (Stryker SpineMask) or robotics (ExcelsiusGPS) were included (navigation 2017-2019, robotics 2019-2021, resulting in prospective cohorts of consecutive patients for each modality). All surgeries had the intraoperative computed tomography workflow. The two cohorts were compared for radiation exposure [fluoroscopy time and radiation dose: image capture, surgical procedure, and overall) and time demand (time for setup and image capture, operative time, and total operating room (OR) time].Results: A total of 244 patients (robotics 111, navigation 133) were included. The two cohorts were similar in terms of baseline demographics, primary/revision surgeries, and fusion levels. For one-level TLIF, total fluoroscopy time, total radiation dose, and % of radiation for surgical procedure were significantly less with robotics compared with navigation (20 vs. 25 s, P <0.001; 38 vs. 42 mGy, P =0.05; 58% vs. 65%, P =0.021). Although time for setup and image capture was significantly less with robotics (22 vs. 25 min, P <0.001) and operative time was significantly greater with robotics (103 vs. 93 min, P <0.001), there was no significant difference in the total OR time (145 vs. 141 min, P =0.25). Similar findings were seen for two-level TLIF as well.Conclusion: Robotics for minimally invasive TLIF, compared with navigation, leads to a significant reduction in radiation exposure both to the surgeon and patient, with no significant difference in the total OR time. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective longitudinal study.Objective: The main goal of this study was to measure the disability after AIS correction, according to the LIV.Summary Of Background Data: Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine that may require surgical correction. If the upper and lower instrumented levels (UIV and LIV) of these fusions are defined by the characteristics of the curve, the long-term consequences of the LIV choices are still partially unknown.Methods: This retrospective longitudinal study collected demographic, radiologic (Lenke classification, Cobb angle), and surgical data (approach, LIV, UIV) on 116 patients operated for AIS fusion on a specialized pediatric spine center were collected. All participants answered SRS30, SF12, lumbar and leg pain Visual Analogue Scales (VAS) at last follow-up. Statistical analysis between LIV (T12L1, L2, L3 or L4L5) and clinical data at last follow-up was realized.Results: The mean follow-up was 87months. The mean increase of back pain VAS per UIV level was 9 mm. No statistically significant difference between the different LIV was found, for SRS30 or SF12 MCS (mental component scale). There was a statistically significant difference between L3 UIV and L4L5 UIV for SF-12 PCS (physical component scale); ( P = 0.03).Conclusion: The long-term consequences of LIV choice mostly affect levels distal to L3. If the LIV is mostly defined by the characteristics of the curve, one level caudally corresponds to +9 mm of back pain VAS at 7 years of follow-up. Surgeons may be aware of the long-term consequence of LIV choice and patients be informed. [ABSTRACT FROM AUTHOR]

Study Design: A monocentric, retrospective radiographic study with 99 asymptomatic volunteers.Objective: The authors performed the postural analysis commonly scheduled when evaluating sagittal balance in a vertebra-by-vertebra manner by enrolling an asymptomatic population. They measured the position and angulation of each vertebra to reveal those for which the spatial positioning could be relevant during spinal surgeries.Summary Of Background Data: Several recent publications detailed the sagittal alignment parameters and focus on global analysis parameters. Some patients with identical commonly evaluated spinal parameters have exhibited very different profiles, with notable differences in vertebral positions and orientations. Therefore, a fine segmental analysis of position of each vertebra could be interest to gain understanding of spine alignment.Materials and Methods: The authors obtained full-spine EOS x-rays of 99 volunteers in the standard free-standing position. We used a validated three-dimensional reconstruction technique to extract current spinal parameters and the positions and angulations of all vertebrae and lumbar discs. Particular attention was paid to the positions and angulations of the apical and transitional vertebrae in the general population and in subgroups according to pelvic incidence (PI).Results: T1 was the most common transitional cervicothoracic vertebra (in 89.9% of subjects) and was oriented downwards by an average of 22.0° (SD=7.3°, minimum=2.3°, maximum=40.1°). The thoracic apex trio of T5 (22.2%), T6 (28.3%), and T7 (36.4%) were equally found. The transitional thoracolumbar vertebrae were L1 (39.4%) and T12 (33.3%). The lumbar apex was usually the L3-L4 disc (36.4%). T1 seemed to be the transitional vertebra (90%) irrespective of the PI. For the other relevant vertebrae, the greater the PI, the more cranial the vertebra.Conclusions: We performed a detailed three-dimensional assessment of overall spinal balance using positional and rotational parameters. The positions and orientations of all vertebrae were specified, particularly the apical and transitional vertebrae.Level Of Evidence: Level 3. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective study of a multicenter Adult Spinal Deformity (ASD) Database.Objective: To investigate the change in Pelvic tilt (PT) imparted by regional changes in lumbar lordosis at 2-year minimum follow up.Summary Of Background Data: The distribution of lumbar lordosis between L1-4 and L4-S1 is known to vary based on pelvic incidence (PI). However, the extent to which regional changes effect PT is not clearly elucidated. This information can be useful for ASD surgical planning.Methods: Operative patients from a multicenter ASD database were included with Lowest Instrumented Vertebrae (LIV) S1/Ilium, >5 levels of fusion, Proximal Junction Kyphosis (PJK) angle < 20, and >5 degrees of change in lumbar lordosis from L4-S1 and L1-4. Radiographic analysis was performed evaluating Thoracic Kyphosis (TK), T10-L2 kyphosis (TL), L1-S1 lordosis (LL), L4-S1 lordosis, L1-4 lordosis, sagittal vertical axis (SVA) and PI-LL from preoperative to postoperative, and change at 2-years follow-up. Stepwise regression analysis was performed in order to determine the relationship between PT and the above radiographic parameters. Health-related quality of life (HRQOL) outcomes were also compared between preoperative and postoperative timepoints at 2 years.Results: 103 patients met inclusion for the study. There was improvement in all the radiographic parameters and HRQOLs at 2 years follow-up (p < 0.01). Stepwise regression model showed an inverse relationship between PT and LL change (r = 0.71, p < 0.01). Regionally, an increase in 10 degrees from L4-S1 correlated with a 2.4 degree decrease in PT (p < 0.01), while an increase in 10 degrees from L1-4 resulted in a 1.6 degree decrease in PT (p < 0.01).Conclusion: In the surgical planning for ASD, our data demonstrated significant correlational difference between corrections in the upper (L1-4) and lower (L4-S1) lumbar spine and PT changes. These calculations can be useful in planning sagittal plane corrections for ASD. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective review of prospectively collected data.Objective: To analyze the postoperative factors that led delayed discharge in patients who would have been eligible for ambulatory lumbar fusion (ALF).Summary Of Background Data: Assessing postoperative inefficiencies is vital to increase the feasibility of ALF.Materials and Methods: Patients who underwent single-level minimally invasive transforaminal lumbar interbody fusion and would have met the eligibility criteria for ALF were included. Length of stay (LOS); time in postanesthesia recovery unit (PACU); alertness and neurological examination, and pain scores at three and six hours; type of analgesia; time to physical therapy (PT) visit; reasons for PT nonclearance; time to per-oral (PO) intake; time to voiding; time to readiness for discharge were assessed. Time taken to meet each discharge criterion was calculated. Multiple regression analyses were performed to study the effect of variables on postoperative parameters influencing discharge.Results: Of 71 patients, 4% were discharged on the same day and 69% on postoperative day 1. PT clearance was the last-met discharge criterion in 93%. Sixty-six percent did not get PT evaluation on the day of surgery. Seventy-six percent required intravenous opioids and <60% had adequate pain control. Twenty-six percent had orthostatic intolerance. The median postoperative LOS was 26.9 hours, time in PACU was 4.2 hours, time to PO intake was 6.5 hours, time to first void was 6.3 hours, time to first PT visit was 17.7 hours, time to PT clearance was 21.8 hours, and time to discharge readiness was 21.9 hours. Regression analysis showed that time to PT clearance, time to PO intake, time to voiding, time in PACU, and pain score at three hours had a significant effect on LOS.Conclusions: Unavailability of PT, surgery after 1  pm , orthostatic intolerance, inadequate pain control, prolonged PACU stay, and long feeding and voiding times were identified as modifiable factors preventing same-day discharge.Level Of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Prospective cohort study.Objective: The aim of this study was to evaluate whether sagittal and spinopelvic alignment correlate with preoperative patient-reported outcomes (PROs) in degenerative lumbar spondylolisthesis (DLS) with spinal stenosis.Summary Of Background Data: Positive global sagittal balance and spinopelvic malalignment are strongly correlated with symptom severity in adult spinal deformity, but this correlation has not been evaluated in DLS.Methods: Patients were enrolled in the Canadian Spine Outcomes Research Network (CSORN) prospective DLS study at seven centers between January 2015 and May 2018. Correlation was assessed between the following preoperative PROs: Oswestry Disability Index (ODI), numeric rating scale (NRS) leg pain, and NRS back pain and the following preoperative sagittal radiographic parameters SS, PT, PI, SVA, LL, TK, T1SPI, T9SPI, and PI-LL. Patients were further divided into groups based on spinopelvic alignment: Group 1 PI-LL<10°; Group 2 PI-LL ≥10° with PT <30°; and Group 3 PI-LL ≥10° with PT ≥30°. Preoperative PROs were compared among these three groups and were further stratified by those with SVA <50 mm and SVA ≥50 mm.Results: A total of 320 patients (61% female) with mean age of 66.1 years were included. Mean (SD) preoperative PROs were: NRS leg pain 7.4 (2.1), NRS back pain 7.1 (2.0), and ODI 45.5 (14.5). Preoperative radiographic parameters included: SVA 27.1 (33.4) mm, LL 45.7 (13.4°), PI 57.6 (11.9), and PI-LL 11.8 (14.0°). Weak but statistically significant correlations were observed between leg pain and PT (r = -0.114) and PI (ρ = -0.130), and T9SPI with back pain ( r  = 0.130). No significant differences were observed among the three groups stratified by PI-LL and PT. No significant differences in PROs were observed between patients with SVA <50 mm compared to those with SVA ≥50 mm.Conclusion: Sagittal and spinopelvic malalignment do not appear to significantly influence baseline PROs in patients with DLS.Level Of Evidence: Prognostic level II. [ABSTRACT FROM AUTHOR]

Study Design: Experimental study.Objectives: The goal of this study was to develop a threedimensional (3D)-printed pedicle subtraction osteotomy (PSO) guide plate system. A 3D model and postoperative computed tomography (CT) data were used to evaluate the accuracy of osteotomy with this system.Summary Of Background Data: The key to the success of spinal orthopedic treatment is an effectively performed osteotomy. A 3D-printed osteotomy plate can be used for preoperative surgical planning. Due to the anatomical complexity of the spinal region, the clinical application of 3D-printed osteotomy plates remains challenging.Methods: The CT scans of 10 patients with thoracolumbar spinal deformities were obtained in the digital imaging and communication in medicine (DICOM) format. The diseased vertebrae and adjacent vertebrae were reconstructed and reduced by computer- aided design software, and an osteotomy plate was designed for the diseased vertebrae. The 3D-printed spinal model and osteotomy plate were used to simulate the operation for PSO. After the operation, the vertebral body treated by osteotomy underwent a CT scan, and the findings were compared with the preoperative design to evaluate the osteotomy accuracy.Results: The new 3D guide plate and spine model were used to successfully simulate 10 cases of PSO, and the comparison of the preoperative and postoperative states indicated that the osteotomy outcomes were excellent.Conclusions: The new 3D-printed PSO guide plate system can be used for preoperative osteotomy planning and demonstrates good accuracy. The results can be used to develop 3D-printed plans for PSO in clinical practice. [ABSTRACT FROM AUTHOR]

Study Design: Collectively, seven cadavers were instrumented with 124 thoracolumbar pedicle screws using VisAR augmented reality/guidance. Sixty-five screws were inserted into four donors using open dissection spine surgery. Fifty-nine screws were positioned in three donors with a minimally invasive spine surgery (MISS) procedure. For both open and MISS, VisAR was used exclusively for pedicle screw navigation.Objective: The objective of this study was to determine the accuracy of pedicle screw placement using VisAR for open spine and MISS procedures.Summary Of Background Data: Pedicle screw placement can be challenging depending on anatomical location and a surgeon's experience. AR may minimize fluoroscopy use and speed screw insertion.Methods: Prior to computed tomography (CT) a series of four image visible April Tag optical fiducials were attached to the backs' of the donors. Resulting images were used preoperatively for planned virtual pedicle screw pathways including entry point, trajectory, and depth. The study link was encrypted on a quick response (QR) code, printed, and viewed in the operating room (OR) by the surgeon using VisAR (HoloLens 2 headset). Viewing the code wirelessly uploads and launches the study, converting the DICOM data to holographic images which register to the fiducials on the donor's back. The annotated pathways for each pedicle were called up by voice command and the surgeon positioned each screw by aligning with the virtual guidance hologram.Results: Overall, 124 pedicle screws were inserted with VisAR navigation with 96% accuracy (Gertzbein-Robbins grades A and B). The combined angle of error was 2.4° and the distance error was 1.9 mm.Conclusion: Augmented reality is a highly accurate, emerging technology for navigating both open and minimally invasive spine surgery techniques with off-the-shelf headset hardware.Level Of Evidence: N/A. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective cohort study.Objective: The purpose of this study was to compare segmental and regional radiographic parameters between anterior interbody fusion (ALIF) and posterior interbody fusion (TLIF) for treatment of L5-S1 isthmic spondylolisthesis, and to assess for changes in these parameters over time. Secondarily, we sought to compare clinical outcomes via patient-reported outcome measures (PROMs) between techniques and within groups over time.Summary Of Background Data: Isthmic spondylolistheses are frequently treated with interbody fusion via ALIF or TLIF approaches. Robust comparisons of radiographic and clinical outcomes are lacking.Methods: We reviewed pre- and postoperative radiographs as well as Patient-Reported Outcomes Measurement Information System (PROMIS) elements for patients who received L5-S1 interbody fusions for isthmic spondylolisthesis in the Mass General Brigham (MGB) health system (2016-2020). Intraclass correlation testing was used for reliability assessments; Mann-Whitney U tests and Sign tests were employed for intercohort and intracohort comparative analyses, respectively.Results: ALIFs generated greater segmental and L4-S1 lordosis than TLIF, both at first postoperative visit (mean 26 days [SE = 4]; 11.3° vs. 1.3°, P  < 0.001; 6.2° vs. 0.3°, P  = 0.005) and at final follow-up (mean 410days [SE = 45]; 9.6° vs. 0.2°, P < 0.001; 7.9° vs. 2.1°, P = 0.005). ALIF also demonstrated greater increase in disc height than TLIF at first (9.6 vs. 5.5 mm, P < 0.001) and final follow-up (8.7 vs. 3.6 mm, P < 0.001). Disc height was maintained in the ALIF group but decreased over time in the TLIF cohort (ALIF 9.6 vs. 8.7 mm, P = 0.1; TLIF 5.5 vs. 3.6 mm, P < 0.001). Both groups demonstrated improvements in Pain Intensity and Pain Interference scores; ALIF patients also improved in Physical Function and Global Health - Physical domains.Conclusion: ALIF generates greater segmental lordosis, regional lordosis, and restoration of disc height compared to TLIF for treatment of isthmic spondylolisthesis. Additionally, ALIF patients demonstrate significant improvements across more PROMs domains relative to TLIF patients.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective observational study.Objective: This study investigated the clinical and radiological results of minimally invasive (MI) versus open transforaminal lumbar interbody fusion (TLIF) in patients with single-level lumbar spondylolisthesis over a 10-year period.Summary Of Background Data: Few studies have compared 10-year follow-up outcomes between MI-TLIF and open TLIF.Methods: We retrospectively collected the outcome data of patients with single-level lumbar spondylolisthesis who underwent TLIF procedures using an MI (n = 108) or open (n = 53) approach. Fifty-two (48%) and 31 (58%) patients in the MI-TLIF and open TLIF groups, respectively, completed the 10-year follow-up. A primary clinical outcome included the Oswestry Disability Index (ODI) as well as visual analog scale (VAS) scores for back and leg pain at baseline and at 2, 5, and 10 years postoperatively. The radiographic fusion rate and incidence of secondary surgery due to adjacent segment disease were assessed at 2, 5, and 10 years postoperatively.Results: Intraoperative blood loss and length of hospitalization were significantly lower in the MI-TLIF group than in the open TLIF group. At 2 years postoperatively, the ODI and VAS scores for back and leg pain were significantly lower in the MI-TLIF group than in the open TLIF group. No significant differences were found in VAS scores for back and leg pain or ODI scores between the two groups at 10 years postoperatively. Radiographic fusion rates and prevalence of secondary surgery for adjacent segment disease were not significantly different between the groups at 10 years postoperatively.Conclusion: Efficacy of MI-TLIF for patients with single-level lumbar spondylolisthesis is comparable to that of open TLIF over 10-years. However, MI-TLIF may have superior perioperative recovery and 2-year postoperative functional outcomes than open TLIF.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective review.Objective: To analyze if shoulder balance continues to change in the postoperative period in patients undergoing selective lumbar fusion for adult spinal deformity (ASD), and secondarily, analyze if shoulder balance correlates with health-related quality of life (HRQOL) outcomes.Summary Of Background Data: Shoulder balance in patients with ASD is poorly understood and has largely been extrapolated from adolescent scoliosis literature.Materials and Methods: Adult patients who underwent selective lumbar fusion (upper instrumented vertebra: Τ9-Τ12, lower instrumented vertebra: L4-Pelvis) for thoracolumbar or lumbar scoliosis (cobb angle > 30°) or sagittal plane deformity with thoracic compensatory curves (cobb angle > 10°) were identified. The clavicular angle (CA) was used to quantify shoulder balance. Shoulder balance was categorized into three groups postoperatively (balanced: CA <2°, mild imbalance: CA 2°-4°, severe imbalance: CA >4°). The average CA and proportion of patients in each shoulder balance group were compared at each postoperative period. Patients with 1-year postoperative HRQOL scores were identified.Results: Eighty-six patients were included. The preoperative CA was 2.7 ± 2.3° and did not significantly change at discharge (2.9 ± 2.4°), 6-weeks (2.5 ± 2.1°), 6-months (2.4 ± 2.2°), 1-year (2.4 ± 2.5°), or 2-years (2.3 ± 1.5°) postoperatively. The proportion of patients in each shoulder balance group did not significantly change from discharge to 6-weeks, 6-months, 1-year or 2-years postoperatively (P > 0.1). At 1-year follow-up, the CA demonstrated no significant correlation with Oswestry Disability Index, Scoliosis Research Society (SRS)-22 score, or SRS-22 subscores. There was no significant association between shoulder balance group and Oswestry Disability Index, SRS-22 score, or SRS-22 subscores.Conclusions: In patients with ASD undergoing selective lumbar fusion, shoulder balance did not change over the postoperative period. From a functional standpoint, shoulder balance demonstrated no correlation with HRQOL scores. In patients undergoing selective lumbar fusion for ASD, shoulder balance may not spontaneously correct over the postoperative period, but this may not be of functional consequence.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective study of data collected prospectively.Objective: To investigate changes in the degree of lower leg radiating pain (LLRP) after selective nerve root block (SNRB) and to evaluate associations of this change with postoperative improvements in symptom severity, functional outcomes, and quality of life.Summary Of Background Data: SNRB is routinely performed as an initial treatment for lumbar foraminal or lateral recess stenosis with LLRP. The degree of improvement after SNRB has been suggested to predict the improvement in postoperative pain and functional outcomes. However, there have been no studies on the predictive value of this parameter.Methods: We enrolled 60 patients who underwent SNRB followed by decompressive surgery. They were divided into three groups. The degree of improvement was evaluated as a percentage of the pre-injection values. Functional outcomes of the spine were assessed using the Oswestry Disability Index (ODI) and Roland-Morris Disability Questionnaire (RMDQ). Quality of life was assessed using the 36-item Short Form Survey (SF-36) physical component score (PCS) and mental component score (MCS). The degree of LLRP was measured preoperatively and at 6, 12, and 24 months after surgery. These functional outcomes were evaluated preoperatively and at 12 and 24 months after surgery.Results: The improvement in LLRP in the short term (6 hours after SNRB) was found to be statistically significantly associated with the improvement in LLRP at 12 months after SNRB (P = 0.044, correlation coefficient = 0.261). No relationship between pain improvement after SNRB and functional outcome was identified.Conclusion: The degree of improvement in symptoms 6 hours after SNRB can predict the degree of improvement in LLRP at 12 months after surgery. However, symptomatic improvement after SNRB does not predict postoperative functional outcome or quality of life.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective cohort study.Objective: The aim of this study was to analyze postoperative complications and recovery patterns in different modified 11-item frailty index (mFI-11) groups after lateral lumbar interbody fusion (LLIF) surgery.Summary Of Background Data: The relationship between the mFI-11 score and LLIF surgery has not been previously reported.Methods: A single-center, consecutive series of patients who underwent LLIF with at least two years of follow-up were retrospectively reviewed. Complications after LLIF surgery were recorded. Clinical outcomes, including the visual analog scale (VAS) for back/leg pain and the Oswestry Disability Index (ODI), were evaluated preoperatively and at 1 and 2 years postoperatively. The proportions of patients who achieved substantial clinical benefit (SCB) for the VAS-B, VAS-L, and ODI were also analyzed.Results: One hundred fifty-two patients included in the present study were grouped according to their mFI-11 score: 0 (n = 39), 0.09 (n = 69), 0.18 (n = 31), and ≥0.27 (n = 13). An mFI-11 score ≥0.27 was a significant predictor of urinary complications (adjusted odds ratio: 3.829, P = 0.013). At 2 years postoperatively, patients in all frailty categories experienced improvements in the VAS for back pain, VAS for leg pain, and ODI, without significant differences between the four groups (p = 0.182, 0.121, and 0.804, respectively). There were also no significant differences in the proportions of patients achieving SCB for back/leg pain and the ODI between the four groups (P = 0.843, 0.957, and 0.915, respectively).Conclusion: An mFI-11 score was found to be independently associated with urologic complications in patients who underwent LLIF. Patients in all frailty categories experienced significant improvements in back pain, leg pain, and the ODI at 1 year and 2 years postoperatively. LLIF surgery may be useful for patients with high frailty index.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective review.Objective: Assess measures of spinal-pelvic balance in predicting functional outcome in patients who underwent posterior spinal fusion for adolescent idiopathic scoliosis (AIS) at minimum 40-year follow-up.Summary Of Background Data: Back pain and long-term function are considered when choosing levels for surgery in AIS patients. Three hundred and fourteen patients underwent fusion for AIS between 1961 and 1977. One hundred and thirty-four patients were located for potential long-term follow-up.Methods: With Institutional Review Board approval, medical records and public resources were used to locate patients. Patients completed health-related quality of life (HRQoL) instruments, and returned for assessment including full radiographs. Radiographs were analyzed for scoliosis measures, and recognized spinal-pelvic measures including the lumbar lordosis, sagittal vertical axis (SVA), pelvic incidence, and pelvic tilt (PT). Bivariate and multivariable analyses were performed to assess the association between spinal-pelvic measures and patient-reported outcomes.Results: Thirty-five of 134 patients agreed to return for complete HRQoL and radiographic follow-up. There were no differences at baseline between those agreeing and declining participation. The cohort was 94% female, had an average age of 60.5 years, and average follow-up of 46 years. In bivariate analysis, pelvic incidence and lumbar lordosis difference (PI-LL) was the only spinal-pelvic parameter which statistically discriminated between patients doing well and not, as assessed by the Oswestry Disability Index and the Patient-reported Outcomes Measurement Information System (PROMIS) Pain Interference and Fatigue instruments. In multivariable analysis, (PI-LL > 9°) was associated with worse scores in PROMIS-Pain Interference, Physical Function, Depression, Fatigue, Social Function and the total Oswestry score. An SVA > 50 mm was associated with worse scores in the Scoliosis Research Society-7.Conclusion: In a cohort of 35 patients with average follow-up of 46 years after posterior spinal instrumentation with Harrington rods (PSIF) for AIS, spinal-pelvic mismatch as identified by (PI-LL > 9°) was associated with inferior HRQoL outcomes. Other spinal-pelvic measures (SVA and PT) were not reliably associated with inferior HRQoL.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective longitudinal cohort study.Objective: To investigate the impact of facet joint opening (FJO) on clinical outcomes after minimally invasive decompression surgery for lumbar spinal stenosis.Summary Of Background Data: Although FJOs have previously been identified as indicators of segmental spinal instability, their impact on clinical outcomes after decompression alone surgery has yet to be investigated.Methods: This study included 296 patients from a single institution who underwent minimally invasive surgery for lumbar spinal stenosis and were followed up for ≥5 years. Our analysis focused on identifying FJOs at the index decompression level (d-FJO) and at multiple levels (m-FJO) (i.e., ≥3 levels within the lumbar segment) using preoperative computed tomography. Clinical outcomes including reoperations, improvement ratio for Japanese Orthopaedic Association score, and achievement of a minimal clinically important difference in visual analogue scale scores for low back pain or leg pain at 5 years were compared between patients with and without d-FJO or m-FJO.Results: There were 129 (44%) and 62 (21%) patients with d-FJO (more common with lateral olisthesis) and m-FJO (less common with spondylolisthesis), respectively. Reoperations were more common in patients with d-FJO than in those without (16% vs. 5%). On Cox proportional hazards analysis, d-FJO was identified as a predictor for revision at the index decompression level (hazard ratio 4.04, P = 0.03), whereas m-FJO was a predictor for revision at other lumbar levels (hazard ratio 3.71, P = 0.03). Patients with m-FJO had slightly lower rates of achieving minimal clinically important difference in visual analogue scale scores for low back pain (34% vs. 52%, P = 0.03) and poorer improvement ratio for Japanese Orthopaedic Association scores (74% vs. 80%, P = 0.03) than those without.Conclusion: FJO at both index decompression level and multiple level were predictors of poor outcomes; patients with FJOs require careful surgical planning or special follow-up.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: Prospective cohort study.Objective: The aim of this article is to compare the mid- to long-term patient-reported outcome measures (PROMs) between single-level total disc arthroplasty (TDA), multi-level TDA, and hybrid constructs (combination of TDA and anterior lumbar interbody fusion [ALIF] across multiple levels) for symptomatic degenerative disc disease (DDD).Summary Of Background Data: The treatment of single-level DDD is well documented using TDA. However, there is still a paucity of published evidence regarding long-term outcomes on multi-level TDA and hybrid constructs for the treatment of multi-level DDD, as well as lack of long-term comparisons regarding treatment of single-level DDD and multi-level DDD.Methods: A total of 950 patients underwent surgery for single-level or multi-level DDD between July 1998 and February 2012 with single-level TDA (n = 211), multi-level TDA (n = 122), or hybrid construct (n = 617). Visual Analog Score for the back (VAS-B) and leg (VAS-L) were recorded, along with the Oswestry Disability Index (ODI) and Roland Morris Disability Questionnaire (RMDQ).Results: All PROMs in all groups showed statistically and clinically significant improvements (P < 0.005) in pain and function that is well above the corresponding minimum clinically important difference (MCID) and exceeds literature thresholds for substantial clinical benefit (SCB). Unadjusted analyses show that there were no statistically significant differences in the change scores between the surgery groups for VAS back and leg pain, and RMDQ up to 8 years' follow-up. Adjusted analyses showed the ODI improvement score for the single group was 2.2 points better (95% confidence interval [CI]: 0.6-3.9, P = 0.009) than in the hybrid group. The RMDQ change score was better in the hybrid group than in the multi-level group by 1.1 points (95% CI: 0.4-1.9, P = 0.003) at 6 months and a further 0.4 point at 2 years (95% CI: 0.1-0.8, P = 0.011).Conclusion: In the setting of meticulous preoperative evaluation in establishing a precision diagnosis, clinically and statistically equivalent results can be achieved when treating symptomatic DDD through single-level TDA, multi-level TDA, and hybrid constructs. These results are sustained at mid- to long-term follow-up.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective comparative study.Objective: The aim of this study was to evaluate the changes in global spinal sagittal alignment (GSSA) following selective anterior spinal fusion (ASF) in patients with Lenke type 5 adolescent idiopathic scoliosis (AIS).Summary Of Background Data: Few studies have assessed the changes in postoperative GSSA, including cervical, thoracic, and lumbosacral sagittal alignment in AIS patients with major thoracolumbar/lumbar (TL/L) curve who underwent selective ASF.Methods: Fifty-two patients with Lenke type 5 AIS (two males and 50 females, mean age at surgery of 16.4 ± 3.1 years) were included in this study. The average final follow-up was 8.3 ± 3.1 years after surgery. The variations of outcome variables were analyzed in various spinal sagittal profiles using radiographic outcomes (pre-operation, immediate post-operation, and final follow-up). The clinical outcomes at the final follow-up were assessed using Scoliosis Research Society (SRS)-22 and Oswestry Disability Index (ODI) questionnaires.Results: The mean Cobb angle of the main TL/L and minor thoracic curve was significantly improved after selective ASF, which was maintained up to the final follow-up. However, in all cases, the various sagittal parameters examined (sagittal vertical axis [SVA], C2-7 SVA, C2-7 lordosis, T1 slope, thoracic kyphosis, T10-L2 kyphosis, lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope), did not significantly change in the immediate postoperative period, and all GSSA parameters were maintained up to the final follow-up. Furthermore, the magnitude of coronal curve correction and fused levels did not affect each GSSA parameter postoperatively. During the period up to the final follow-up, no significant clinical symptoms were observed. The final SRS-22 global score was 4.5 ± 0.3, and ODI scored 0.8 ± 2.4.Conclusion: Selective ASF did not influence various GSSA parameters postoperatively and could maintain excellent correction for coronal deformity with satisfactory final functional and clinical outcomes confirmed by long-term follow-up.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective single center propensity-matched observational cohort study that included patients who underwent 1- to 3-level lumbar fusion surgery for degenerative conditions.Objective: To compare 90-day complication rates between robotic-assisted and non-robotic-assisted lumbar spinal fusions in propensity-matched cohorts.Summary Of Background Data: A recent administrative database (PearlDiver) study reported increased 30-day complications with the utilization of robotic-assisted enabling technology.Methods: Of 146 robotic-assisted cases that met inclusion criteria, 114 were successfully propensity matched to 114 patients from 214 cases who had 1 to 3 level lumbar fusion without robotic assistance based on age, sex, body mass index, smoking status, American Society of Anesthesiologist grade, number of surgical levels, primary versus revision, and surgical approach (posterior-only or anterior-posterior). We excluded tumor, trauma, infection, or deformity cases. Outcomes included surgical and medical (major/minor) complications at intraoperative, immediately postoperative, 30- and 90-day postoperative intervals, including reoperations, and readmissions within 90 days.Results: All cause intraoperative complication rates were similar between non-robotic-assisted (5.3%) and robotic-assisted groups (10.5%, P = 0.366). Immediate postoperative medical complication rate was also similar between non-robotic-assisted (6.1%) and robotic-assisted groups (1.8%, P = 0.089). Thirty-day complication rates, 90-day complication rates, reoperation rates, and readmission rates showed no difference between non-robotic-assisted and robotic-assisted groups. There was no difference between return to OR for infection between the cohorts (non-robotic-assisted: 6 [5%] vs. robotic-assisted: 1 [0.8%], P = 0.119). There was however improved length of stay (LOS) in the robotic-assisted group compared with non-robotic-assisted group (2.5 vs. 3.17 days, P = 0.018).Conclusion: In propensity-matched cohorts, patients undergoing 1- to 3-level robotic-assisted posterior lumbar fusion for degenerative conditions did not have increased 90-day complication rate, and had a shorter length of stay compared with non-robotic-assisted patients. There findings differ from a prior administrative database study as the robotic-assisted group in the current study had 0% return to OR for malpositioned screws and 0.8% return to OR for infection.Level of Evidence: 2. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective analysis of a prospective, non-randomized cohort dataset.Objective: To cross-sectionally examine the prevalence of sarcopenia and the association between spine-pelvic deformity and skeletal muscle volume loss and ectopic fat infiltration into lumbar paravertebral muscles (PVMs) in patients who underwent lumbar surgery.Summary Of Background Data: Muscle quality deterioration has been considered the main pathology of sarcopenia, reducing muscle strength directly. The qualitative deterioration as well as volume loss in PVM, which contributes significantly to core body extension, might cause aging-related spine deformity.Methods: In total, 184 patients were included. Sarcopenia was diagnosed at baseline, and all patients underwent whole-body X-ray. The amount of fat in lumbar PVM was evaluated with the Goutallier classification in magnetic resonance imaging findings. The expression of adipogenesis- and atrophy-promoting factors in PVM was evaluated with quantitative polymerase chain reaction.Results: In total, 36.1% of adults aged ≥60 years were diagnosed with sarcopenia. The values of skeletal muscle indexes of the limb and trunk were inversely correlated with the sagittal vertical axis, pelvic tilt (PT), and pelvic incidence minus lumbar lordosis (PI-LL) values. The PT and PI-LL were greater, PVM area was smaller, and Goutallier grade was greater in sarcopenic adults than in non-sarcopenic older adults. Additionally, the PVM area correlated with the LL value, and Goutallier's grade correlated with the PT and PI-LL values. Moreover, the amount of ectopic fat in PVMs inversely correlated with skeletal muscle indexes. The expression levels of atrophy gene-1 and muscle ring-finger protein-1 did not differ between the groups and did not correlate with the PVM area. In contrast, the expression of Pparg and Cebpa was upregulated in sarcopenic older adults, where it correlated with Goutallier's grade.Conclusion: The volume loss of skeletal muscle, including lumbar PVM, and ectopic fat infiltration into the PVM, may cause the lumbo-pelvic deformity.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: This was a dual-center study over an eight-year period on patients undergoing single level fusion surgery with either posterior- (PLIF) or transforaminal lumbar interbody fusion (TLIF). We analyzed prospectively collected pre- and postoperative data from the national Danish surgical spine database (DaneSpine).Objective: The aim of this study was to compare clinical and patient-reported outcome (PRO) 2 years after TLIF or PLIF in patients with symptomatic lumbar mechanical disc degeneration.Summary Of Background Data: PLIF and TLIF are well-described techniques for treating lumbar mechanical disc degeneration but whether the theoretical differences between the two techniques translate to different clinical outcomes is unknown.Methods: The primary outcome was Oswestry Disability Index (ODI) score at 2-year follow-up. Secondary outcome measures were scores on the European Quality of Life-5 Dimensions (EQ-5D) and visual analog scale (VAS) and the rate of intraoperative complications. To minimize baseline differences between the groups, propensity-score matching was employed in a 1:1 fashion, balancing the groups on preoperative factors including age, sex, back and leg pain, ODI, EQ-5D, and previous spine surgery.Result: The matched cohort included 211 patients in each cohort. There was no significant difference between the groups in the mean score on the ODI at two years (PLIF: 33 ± 20 vs. TLIF: 35 ± 20, P = 0.328). We found no statistically significant differences in EQ-5D score (0.54 ± 0.35 vs. 0.51 ± 0.34, P = 0.327), VAS score for back pain (47 ± 32 vs. 48 ± 29, P = 0.570) or leg pain (42 ± 33 vs. 41 ± 32, P = 0.936) between the PLIF and TLIF groups, respectively, at 2-year follow-up. Dural tears occurred in 9.5% in the PLIF group and 1.9% in the TLIF group (P = 0.002) corresponding to a relative risk of 5.0 (95% CI 1.7-14.4).Conclusion: We found no significant difference in PRO at 2-year follow-up between PLIF and TLIF for the treatment of lumbar disc degeneration. PLIF is associated with a five times higher risk of dural tears.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective study.Objectives: The aim of this study was to review clinical and imaging features in patients with lumbar spinal canal stenosis (LSS) with and without postoperative early progression of intervertebral disc degeneration (IDD) and to identify predictive factors.Summary Of Background Data: Progression of IDD after lumbar decompression surgery can induce low back pain and leg pain, and may require revision surgery. However, risk factors for postoperative radiological changes indicating IDD linked to development of symptoms have not been described.Methods: We included 564 patients with LSS without degenerative lumbar scoliosis who underwent lumbar decompression surgery without fusion. Clinical features and imaging findings were compared in cases with (group P) and without (group N) progression of IDD (intervertebral disc wedge or narrowing) at 1 year after surgery.Results: Of the 564 patients, 49 (8.7%) were in group P. On preoperative MRI, all patients in group P had findings of vertebral bone marrow edema (diffuse high intensity on T2-weighted images and low-intensity on T1-weighted images), compared to only 5.4% in group N. The rate of revision surgery was significantly higher in group P in 5 years' follow-up (12.2% vs. 1.4%, P < 0.01). In group P, 44.9% of patients developed postoperative symptoms associated with postoperative radiological changes, and the frequency was higher in narrowing-type than in wedge-type cases. Vertebral bone marrow edema area and IDD grade were not predictors for postoperative early IDD progression.Conclusion: Careful consideration is required to determine whether lumbar decompression surgery should be performed if vertebral bone marrow edema is detected on MRI, since this is a predictor for a negative clinical outcome. If surgery is symptomati-cally urgent, careful clinical and radiological follow-up is required.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Prospective, randomized, controlled preclinical study.Objective: The objective of this study was to compare the host inflammatory response of our previously described hyperelastic, 3D-printed (3DP) hydroxyapatite (HA)-demineralized bone matrix (DBM) composite scaffold to the response elicited with the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in a preclinical rat posterolateral lumbar fusion model.Summary Of Background Data: Our group previously found that this 3D-printed HA-DBM composite material shows promise as a bone graft substitute in a preclinical rodent model, but its safety profile had yet to be assessed.Methods: Sixty female Sprague-Dawley rats underwent bilateral posterolateral intertransverse lumbar spinal fusion using with the following implants: 1) type I absorbable collagen sponge (ACS) alone; 2) 10 μg rhBMP-2/ACS; or 3) the 3DP HA-DBM composite scaffold (n = 20). The host inflammatory response was assessed using magnetic resonance imaging, while the local and circulating cytokine expression levels were evaluated by enzyme-linked immunosorbent assays at subsequent postoperative time points (N = 5/time point).Results: At both 2 and 5 days postoperatively, treatment with the HA-DBM scaffold produced significantly less soft tissue edema at the fusion bed site relative to rhBMP-2-treated animals as quantified on magnetic resonance imaging. At every postoperative time point evaluated, the level of soft tissue edema in HA-DBM-treated animals was comparable to that of the ACS control group. At 2 days postoperatively, serum concentrations of tumor necrosis factor-α and macrophage chemoattractant protein-1 were significantly elevated in the rhBMP-2 treatment group relative to ACS controls, whereas these cytokines were not elevated in the HA-DBM-treated animals.Conclusion: The 3D-printed HA-DBM composite induces a significantly reduced host inflammatory response in a preclinical spinal fusion model relative to rhBMP-2.Level of Evidence: N/A. [ABSTRACT FROM AUTHOR]

Study Design: A radiographic comparative study.Objective: To investigate the influence of radiographic lower limb-spinal length proportion on sagittal radiographic parameters.Summary Of Background Data: Although lordotic realignment of the lumbar spine is a well-established surgical strategy, its ideal target has not been fully understood. The widely used pelvic incidence-lumbar lordosis discrepancy (PI-LL) method to guide lordotic restoration of the lumber spine in the standing posture, may be further refined using the novel, radiographic lower limb-spinal length proportion parameter in selected subjects.Methods: A 100 healthy subjects were imaged in the standing posture using EOS imaging to obtain whole-body lateral radiographs for the measurement of sagittal radiographic parameters. Univariate analyses were performed to compare radiographic parameters between groups with different radiographic lower limb-spinal length proportion. Multivariate analyses were performed to identify the associations between lower limb-spinal length proportions and other radiographic parameters.Results: Regardless of lower limb-spinal length proportion (mean = 1.4), global lumbar angle (GLA) differed from spinal lordosis (SL), with the absolute means of SL and GLA larger and smaller than pelvic incidence (PI) respectively. Univariate analysis showed that patients with proportionately larger lower limb-spinal length proportion are more likely to have larger mean T1-slope, global thoracic angle (GTA), spinal kyphosis (SK), GLA, and SL. Multivariate analysis showed that a larger lower limb length-spinal length proportion is predictive of larger GLA is less than -47.69° (Odds Ratio (OR) 2.660, P = 0.026), and larger T1-slope of more than 18.84° (OR 3.695, P = 0.012).Conclusion: Larger radiographic lower limb-spinal length proportion results in naturally accentuated spinal curves. These patients balance with a larger lumbar lordosis that is closer to the PI and a higher T1-slope which should be considered for spinal realignment. SL differs from GLA and should be separately assessed.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective, single-center, observational study.Objective: The aim of this study was to determine the prevalence and the characteristics of adolescent idiopathic scoliosis (AIS) patients with concomitant lumbar spondylolysis.Summary Of Background Data: The prevalence and features of lumbar spondylolysis in patients with AIS are unclear.Methods: We included 357 patients with AIS who underwent correction and fusion surgery. Preoperative computed tomography (CT) images were used to assess the existence of lumbar spondylolysis. Cobb angles of the curves, parameters of spinal alignment, Lenke classification, and the presence of low back pain were compared between patients with and without spondylolysis.Results: Of the patients included in the study, 6.1% had lumbar spondylolysis. They had significantly greater lumbar lordosis (LL) and sacral slope (SS) than those without lumbar spondylolysis. Logistic regression analyses and receiver-operating characteristic curves showed that LL was a significant risk factor (odds ratio: 1.059; 95% confidence interval: 1.018-1.103; P = 0.005) of associating lumbar spondylolysis with a cut off value of 56.5 degrees (area under the curve [AUC]: 0.689; sensitivity = 63.6%, specificity = 71.0%).Conclusion: We should be vigilant for lumbar spondylolysis in AIS patients whose LL and SS are large, especially with LL larger than 56.5°.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: Multicenter cohort.Objective: To compare the robot time/screw, radiation exposure, robot abandonment, screw accuracy, and 90-day outcomes between robot-assisted percutaneous and robot-assisted open approach for short lumbar fusion (1- and 2-level).Summary Of Background Data: There is conflicting literature on the superiority of robot-assisted minimally invasive spine surgery to open techniques. A large, multicenter study is needed to further elucidate the outcomes and complications between these two approaches.Methods: We included adult patients (≥18 yrs old) who underwent robot-assisted short lumbar fusion surgery from 2015 to 2019 at four independent institutions. A propensity score matching algorithm was employed to control for the potential selection bias between percutaneous and open surgery. The minimum follow-up was 90 days after the index surgery.Results: After propensity score matching, 310 patients remained. The mean (standard deviation) Charlson comorbidity index was 1.6 (1.5) and 53% of patients were female. The most common diagnoses included high-grade spondylolisthesis (grade >2) (48%), degenerative disc disease (22%), and spinal stenosis (25%), and the mean number of instrumented levels was 1.5(0.5). The operative time was longer in the open (198 min) versus the percutaneous group (167 min, P value = 0.007). However, the robot time/screw was similar between cohorts (P value > 0.05). The fluoroscopy time/ screw for percutaneous (14.4 s) was longer than the open group (10.1 s, P value = 0.021). The rates for screw exchange and robot abandonment were similar between groups (P value > 0.05). The estimated blood loss (open: 146 mL vs. percutaneous: 61.3 mL, P value < 0.001) and transfusion rate (open: 3.9% vs. percutaneous: 0%, P value = 0.013) were greater for the open group. The 90-day complication rate and mean length of stay were not different between cohorts (P value > 0.05).Conclusion: Percutaneous robot-assisted spine surgery may increase radiation exposure, but can achieve a shorter operative time and lower risk for intraoperative blood loss for short-lumbar fusion. Percutaneous approaches do not appear to have an advantage for other short-term postoperative outcomes. Future multicenter studies on longer fusion surgeries and the inclusion of patient-reported outcomes are needed.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: Michigan Spine Surgery Improvement Collaborative (MSSIC) prospectively collects data on all patients undergoing operations for degenerative and/or deformity indications.Objective: We aimed to identify which factors are significantly associated with return-to-work after lumbar surgery at long-term follow-up.Summary Of Background Data: Prior publications have created a clinically relevant predictive model for return-to-work, wherein education, gender, race, comorbidities, and preoperative symptoms increased likelihood of return-to-work at 3 months after lumbar surgery. We sought to determine if these trends 1) persisted at 1 year and 2 years postoperatively; or 2) differed among preoperatively employed versus unemployed patients.Methods: MSSIC was queried for all patients undergoing lumbar operations (2014-2019). All patients intended to return-to-work postoperatively. Patients were followed for up to 2 years postoperatively. Measures of association were calculated with multivariable generalized estimating equations.Results: Return-to-work increased from 63% (3542/5591) at 90 days postoperatively to 75% (3143/4147) at 1 year and 74% (2133/2866) at 2 years postoperatively. Following generalized estimating equations, neither clinical nor surgical variables predicted return-to-work at all three time intervals: 90 days, 1 year, and 2 years postoperatively. Only socioeconomic factors reached statistical significance at all follow-up points. Preoperative employment followed by insurance status had the greatest associations with return-to-work. In a subanalysis of patients who were preoperatively employed, insurance was the only factor with significant associations with return-to-work at all three follow-up intervals. The return-to-work rates among unemployed patients at baseline increased from 29% (455/1100) at 90 days, 44% (495/608) at 1 year, and 46% (366/426) at 2 years postoperatively. The only two significant factors associated with return-to-work at all three follow-up intervals were Medicaid, as compared with private insurance, and male gender.Conclusion: In patients inquiring about long-term return-to-work after lumbar surgery, insurance status represents the important determinant of employment status.Level of Evidence: 2. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective study.Objective: The aim of this study was to investigate whether there is an association between revision surgery rates for adjacent segment degeneration (ASD) and Roussouly type after L4-5 transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis.Summary Of Background Data: Revision surgery for ASD is known to occur after spinal fusion; however, it is unclear whether rates of ASD are associated with certain Roussouly types.Methods: Patients who underwent L4-5 TLIF for spondylolisthesis at the University of California San Francisco from January 2006 to December 2016 with minimum 2-year follow-up were retrospectively analyzed by Roussouly type. Revision surgery for ASD was noted and correlated by Roussouly type. Spinopelvic parameters were also measured for correlation. A value of P < 0.05 was significant.Results: There were 174 patients who met inclusion criteria, (59 males and 115 females). The average age was 62.3 (25-80) years. A total of 132 patients had grade I spondylolisthesis, and 42 had grade II. Mean follow-up was 45.2 months (24-497). A total of 22 patients (12.6%) underwent revision surgery for ASD after L4-5 TLIF. When classified by Roussouly type, revision surgery rates for ASD were: 1, 14.3%; 2, 22.6%; 3, 4.9%; and 4, 15.6% (P = 0.013). Type 3 spines with normal PI-LL (8.85° ± 6.83°) had the lowest revision surgery rate (4.9%), and type 2 spines with PI-LL mismatch (11.06° ± 8.81°) had the highest revision surgery rate (22.6%), a four-fold difference (P = 0.013). The PI-LL mismatch did not change significantly in each type postoperatively (P > 0.05).Conclusion: We found that there may be a correlation between Roussouly type and revision surgery for ASD after L4-5 TLIF for spondylolisthesis, with type 2 spines having the highest rate. Spinopelvic parameters may also correlate with revision surgery for ASD after L4-5 TLIF.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective case-control study.Objective: To evaluate the prevalence of pseudarthrosis following ATP lumbar and lumbosacral fusions.Summary Of Background Data: Pseudarthrosis is a feared complication following spinal fusions and may affect their clinical outcomes. To date there is no sufficient data on the fusion rate following antepsoas (ATP) lumbar and lumbosacral arthrodesis.Methods: This is a retrospective review of 220 patients who underwent lumbar MIS-ATP fusions between January 2008 and February 2019 who have at least one-year postoperative computed tomography (CT) follow-up scans. Fusion was graded using CT scans imaging and adopting a 1-4 grading scale (1-definitely fused, 2-likely fused, 3-likely not fused, 4-definitely not fused/nonunion). Grades 3 or 4 indicate pseudarthrosis.Results: A total of 220 patients [average age: 66 years, 82 Male (37.2%), and 127 (57.7%) smokers] were included. Eight patients (3.6%) developed pseudarthrosis. A total of 693 discs were addressed using the ATP approach. Of those, 681 (98.3%) were considered fused [641 levels (92.5%) were "definitely fused" and 40 levels (5.8%) were "Likely fused"] and 12 discs (1.7%) developed pseudarthrosis [7 levels (1.0%) were "likely not fused" and 5 levels (0.7%) were "definitely not fused"]. The highest rate of pseudarthrosis was found at L5-S1 (4.8%) compared to the L1-L5 discs (0-2%). Of 127 smokers, 6 developed pseudarthrosis (Odds Ratio = 2.3, p = 0.3). The fusion rates were 95.3% and 97.8% for smokers and nonsmokers, respectively. Of the eight patients who developed pseudarthrosis, only 4 (50%) were symptomatic, of whom 2 (25%) required revision surgery. Both of these patients were smokers. The overall revision rate due to pseudarthrosis was 0.9% (2/220 patients).Conclusion: The MIS-ATP technique results in a high fusion rate (96.4% of patients; 98.3% of levels). Pseudarthrosis was noted mostly at the L5-S1 discs and in smokers.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: A biomechanical comparison study using finite element method.Objective: The aim of this study was to investigate effects of different dynamic stabilization devices, including pedicle-based dynamic stabilization system (PBDSS) and interspinous process spacer (ISP), used for topping-off implants on biomechanical responses of human spine after lumbar interbody fusion.Summary Of Background Data: Topping-off stabilization technique has been proposed to prevent adjacent segment degeneration following lumbar spine fusion. PBDSS and ISP are the most used dynamic stabilizers for topping-off instrumentation. However, biomechanical differences between them still remain unclear.Methods: A validated, normal FE model of human lumbosacral spine was employed. Based on this model, rigid fusion at L4-L5 and moderately disc degeneration at L3-L4 were simulated and used as a comparison baseline. Subsequently, Bioflex and DIAM systems were instrumented at L3-L4 segment to construct PBDSS-based and ISP-based topping-off models. Biomechanical responses of the models to bending moments and vertical vibrational excitation were computed using FE static and random response analyses, respectively.Results: Results from static analysis showed that at L3-L4, the response parameters including annulus stress and range of motion were decreased by 41.6% to 85.2% for PBDSS-based model and by 6.3% to 67% for ISP-based model compared with rigid fusion model. At L2-L3, these parameters were lower in ISP-based model than in PBDSS-based model. Results from random response analysis showed that topping-off instrumentation increased resonant frequency of spine system but decreased dynamic response of annulus stress at L3-L4. PBDSS-based model generated lower dynamic stress than ISP-based model at L3-L4, but the dynamic stress was higher at L2-L3 for PBDSSbased model.Conclusion: Under static and vibration loadings, the PBDSSbased topping-off device (Bioflex) provided a better protection for transition segment, and likelihood of degeneration of supraadjacent segment might be relatively lower when using the ISPbased topping-off device (DIAM).Level of Evidence: 5. [ABSTRACT FROM AUTHOR]

Study Design: This is an anatomic study using cadaveric material.Objective: To provide anatomic descriptions of the normal lumbar sublaminar ridge in the lateral recess and it's potential to impact on the exiting nerve root there, with implications to surgical technique in lumbar spinal stenosis.Summary Of Background Data: The lateral extent of the sublaminar ridge - the bony, superior insertion site of the ligamenta flava - and its topological relationship to the nerve root are not described in the literature. In the setting of degenerative lumbar stenosis this structure can hypertrophy and impinge the nerve root within the lateral recess even after excision of the corresponding ligamentum flavum. Failure to address this may contribute to failed lateral recess decompression.Methods: Fifteen lumbar vertebrae, not obviously degenerated, were resected en bloc from three fixed adult human cadavers and then transected through the pedicles, leaving the posterior column and neural elements intact and articulated. The shape of the sublaminar ridge in the lateral recess and its relationship to the exiting nerve root were carefully examined.Results: The exiting nerve root consistently crosses the sublaminar ridge immediately inferior to the mid-pedicle, lateral to the subarticular gutter and on the medial aspect of the true intervertebral foramen. A hypertrophic ridge can compress the exiting root by elevating the nerve root superiorly against the bony underside of the pedicle or displacing it anteriorly against the disc or vertebral body.Conclusion: The sublaminar ridge in the lateral recess may contribute to degenerative lumbar stenosis. Comprehensive appreciation of this anatomy may facilitate thorough lateral recess decompression.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective study.Objective: To compare the accuracy of pedicle screw placement and proximal facet joint violation (FJV) in single-level degenerative lumbar diseases using cortical bone trajectory (CBT) and traditional trajectory (TT) techniques, and analyze their possible risk factors.Summary Of Background Data: CBT screws have been utilized increasingly to improve cortical bone contact to prevent screw pullout and reduce approach-related morbidity. However, the studies on intra-pedicular accuracy and proximal FJV between the two methods are rare.Methods: A total of 40 patients who required single-level instruments were included in the retrospective study treated with the CBT-TLIF and the TT-TLIF at a 1:1 ratio from March 2019 to August 2020. The radiographic outcomes were the intra-pedicular accuracy and proximal FJV. Moreover, the possible risk factors were assessed using bivariate and multivariate analyses.Results: As for the intra-pedicular accuracy, 73 screws (91.3%) were classified as grade A, 7 screws (8.7%) classified as grade B in the CBT group. A total of 71 screws (88.8%) were graded A with remaining 8 screws (10.0%) graded B and 1 screw (1.2%) graded C in the TT group. The proportion of optimal and clinically acceptable screw positions in the two groups were not significantly different (P > 0.05). In addition, the rate of proximal FJV in CBT approach (8.3%) was significantly lower than that in the TT approach (35.0%) (P < 0.001). Multivariate analysis showed the TT insertion approach and facet angle ≥45° were the independent risk factors for proximal FJV, but no factors above affected intra-pedicular accuracy.Conclusion: Compared with the TT approach in TLIF, the CBT approach showed similar intra-pedicular accuracy and remarkable superiority in proximal facet joint protection. Facet angle ≥45° is the independent risk factors for proximal FJV.Level of Evidence: 2. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective cohort.Objective: The aim of this study was to elucidate the relative influence of multiple factors on radiation usage for anterior, lateral, and posterior based lumbar interbody fusion techniques.Summary Of Background Data: There has been substantial global growth in the performance of lumbar interbody fusions, due to evolution of techniques and approaches and increased attention to sagittal alignment. Utilization of intraoperative imaging guidance has similarly expanded, with a predominance of fluoroscopy and consequent increased radiation exposure. There have been no larger-scale studies examining the role of patient and procedural factors in driving radiation exposure across different interbody techniques.Methods: We used a clinical registry to review all single-level lumbar interbody fusions performed between January 2016 and October 2020. Operative records were reviewed for the amount of radiation exposure during the procedure. Patient age, biologic sex, body mass index (BMI), operative surgeon, surgical level, surgical time, and fusion technique were recorded. Multivariable adjusted analyses using negative binomial regression were used to account for confounding.Results: We included 134 interbody fusions; 80 performed with a posterior approach (TLIF/PLIF), 43 via an anterior approach (ALIF) with posterior pedicle fixation, and 9 performed with a lateral approach (LLIF/XLIF). Average radiation per case was 136.4 mGy (SE 17.3) for ALIF, 108.6 mGy (16.9) for LLIF/XLIF, and 60.5 mGy (7.4) for TLIF/PLIF. We identified lateral approaches, increased BMI, minimally invasive techniques, and more caudal operative levels as significantly associated with increased radiation exposure.Conclusion: We identified several novel drivers of radiation exposure during interbody fusion procedures, including the relative importance of technique and the level at which the fusion is performed. More caudal levels of intervention and lateral based techniques had significantly greater radiation exposure.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective comparative study with radiographic measurements.Objective: The aim of this study was to investigate incidences and risk factors of screw-related superior facet articular surface violation (FASV) and optimal pedicle screw angles (PSAs) to avoid FASV at L4 and L5 levels in transforaminal lumbar interbody fusion (TLIF) with either open surgery (OS) or minimal invasive (MIS) techniques with 3D C-arm navigation.Summary Of Background Data: L4 to S1 are common levels in TLIF. Adjacent segment diseases (ASD) following TLIF is not uncommon. Screw-related FASV at the superior level is one of the potential risk factors for ASD.Methods: In the OS and MIS groups, 111 and 110 screws were included at L4 level, and 114 and 110 screws at L5 level, respectively. Postoperative computed tomography examined screw-related FASV at L3-4 and L4-5 facet levels. The entry point was the location where pedicle screws placed into the facet joints.Results: The OS technique and insertion at the L5 level increased the likelihood of FASV 2.56 and 1.81 times, respec-tively. Multivariate logistic regressions analysis determined PSA was a significant factor associated with FASV. Pearson r between PSA and the distance between midline and entry point was 0.905 (P < .0001). Adding one degree of convergence in PSA led to a mean 0.87 lower odds of an FASV event, regardless of surgical techniques. In 90% of patients in the OS and MIS groups, PSA with FASV was < 11.9° and <15.9° at L4 level, and <15.9° and <21.8° at L5 level, respectively.Conclusion: PSAs played an important role in FASV. MIS allowed greater PSAs and resulted in fewer incidences of FASV. To avoid FASV in 90% of patients, the PSAs might be at least 11.9° and 15.9° at L4 level, and 15.9° and 21.8° at L5 level for OS and MIS techniques, respectively.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective study.Objectives: The purpose of this study was to evaluate optimal and ideal target values of the spine balance correction in elderly patients with adult spinal deformity who were over the age of 60 years.Summary Of Background Data: The target values of the Scoliosis Research Society -Schwab classification to obtain satisfactory alignment and favorable outcomes are used in many spinal reconstruction surgeries. However, uniformly applying the Scoliosis Research Society-Schwab classification to all elderly patients aged 60 years or older showing sagittal malalignment may lead to several inconsistencies.Methods: This study included 121 patients (average age 70.5 yr and a minimum 2-yr follow-up) with adult spinal deformity who underwent long-segment fusion from T10 to sacrum. We used Pearson's correlation coefficient to analyze the relationship between clinical and radiographic parameters, and multilinear regression analysis and multivariate logistic regression model (backward elimination method) were conducted using the correlation factors of postoperative (Post) and last follow-up (Last) sagittal vertical axis to find the risk factors of Post sagittal imbalance.Results: Logistic regression analysis with the correlation factors of Post and Last sagittal vertical axis led to risk factors of Post sagittal imbalance, and after confirming the significance of each path, it was confirmed that the effects of pelvic incidence (PI)- lumbar lordosis (LL) and Post pelvic tilt ratio (PTr) were valid (P < 0.05). After using ROC curve, target value of PI-LL was 1.33, and that of PTr was 25.95%.Conclusion: Through our study, the risk factors of Post sagittal imbalance were the Post value of PI-LL and that of PTr, and target value of PI-LL was <1.33 and that of PTr was <25.95%. These target values can be effective guidelines for spine surgeons who perform spine reconstruction surgeries for elderly patients with a pure sagittal imbalance based on Schwab's formula.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective cohort study.Objective: The aim of this study was to investigate the differences in Medicare reimbursement for one- to three-level lumbar decompression procedures performed at a tertiary referral center versus an orthopedic specialty hospital (OSH).Summary Of Background Data: Lumbar decompression surgery is one of the most commonly performed spinal procedures. Lumbar decompression also comprises the largest proportion of spinal surgery that has transitioned to the outpatient setting.Methods: Patients who underwent a primary one- to three- level lumbar decompression were retrospectively identified. Reimbursement data for a tertiary referral center and an OSH were compiled through Centers for Medicare and Medicaid Services. Demographic data, surgical characteristics, and time cost data were collected through chart review. Multivariate regression models were used to determine independent factors associated with total episode of care cost, operating room (OR) time, procedure time, and length of stay (LOS), and to determine independent predictors of having the decompression performed at the OSH.Results: Total episode of care, facility, and non-facility payments were significantly greater at the tertiary referral center than the OSH, as were OR time for one- to three-level procedures, procedure time of all pooled levels, and LOS for one- and two-level procedures. Three-level procedure was independently associated with increased OR time, procedure time, and LOS. Age and two-level procedure were also associated with increased LOS. Procedure at the OSH was associated with decreased OR time and LOS. Charlson Comorbidity Index was a negative predictor of decompression being performed in the OSH setting.Conclusion: Significant financial savings to health systems can be expected when performing lumbar decompression surgery at a specialty hospital as opposed to a tertiary referral center. Patients who are appropriate candidates for surgery in an OSH can in turn expect faster perioperative times and shorter LOS.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A multicenter, retrospective study.Objective: To clarify the clinical and radiological effects of removing interspinous contextures in lumbar decompression surgery for patients with lumbar spinal stenosis.Summary Of Background Data: There have seldom been reports that have compared both clinical results and radiological changes among minimally invasive decompression methods.Methods: Consecutive 52 patients underwent lumbar spinous process-splitting laminectomy (LSPSL), following which 50 patients underwent trans-interspinous lumbar decompression (TISLD). All patients presented with cauda equina type of lumbar spinal stenosis and underwent a minimum 1-year follow-up. The Japanese Orthopaedic Association (JOA) score and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) score were evaluated to determine the extent of daily living activities. Propensity score (PS)-matched analysis was used to match patients' age and preoperative JOA scores between the two groups. Lumbar lordosis (LL), disc height (DH), segmental range of motion (ROM), and vertebral anterior translation were measured by functional lumbar lateral x-ray, and changes between preoperative and 1-year postoperative values were evaluated.Results: Twenty-nine pairs of patients were selected by PS-matching. Mean JOA scores increased from 14.4 to 23.5 (mean recovery rate was 62.3%) in the LSPSL group and from 14.0 to 23.2 (61.3%) in the TISLD group at preoperative and 1-year follow-up, respectively. There were no significant differences in clinical results and changes in LL, ROM, and vertebral anterior translation in each group. The DH at L4/5 level at 1-year after surgery revealed significant decrease in the TISLD group compared with the LSPSL group. There was a correlation between preoperative DH and DH decrease in the LSPSL group, but not in TISLD group.Conclusion: Removal of interspinous contextures did not influence clinical outcomes at 1 year after surgery, but it may be likely to cause disc height loss when it applied at the L4/5 level.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective cohort study.Objective: The aim of this study was to compare different aspects of fusion surgery in patients with osteoporosis with regard to graft subtype and surgical approach.Summary Of Background Data: Osteoporosis and chronic lower back pain are common in elderly populations and significantly increase the risk of compression fractures within the spine.Methods: Using the 2016-2017 National Readmission Database we identified 11,086 osteoporotic patients who received lumbar fusion using ICD-10 coding. Information regarding biologic graft type and surgical approach was collected. Patients were stratified by number of levels fused. Perioperative complications were collected at 30-, 90-, and 180-day follow-up intervals. Statistical analysis included univariate testing and multivariate regression modeling, controlling for patient demographics and comorbidities.Results: Patients receiving single-level fusion with autologous grafts had higher rates of hardware failure (P = 0.00014) at 30-day follow-up and 90-day follow-up (P < 0.0001) and higher rates of lumbar vertebral fractures at 90-day follow-up (P = 0.045) compared to those treated with nonautologous grafts. Patients receiving lumbar fusion with anterior and posterior approaches had no difference in readmission or infection rates, but the anterior approach was associated with a higher cost.Conclusion: In this study, osteoporotic patients treated with autologous grafts had higher rates of complications compared to those treated with nonautologous grafts. Anterior and posterior approaches had similar complication rates; however, the anterior approach was associated with a higher total cost.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Pre-clinical study in rodents.Objective: To investigate changes in biomechanical properties of paraspinal muscles following a posterior spinal surgery in an animal model SUMMARY OF BACKGROUND DATA.: Posterior spine surgery damages paraspinal musculature per histological and imaging studies. The biomechanical effects of these changes are unknown.Methods: 12 Sprague-Dawley rats were divided equally into sham and surgical injury (SI) groups. For sham, the skin and lumbodorsal fascia were incised at midline. For SI, the paraspinal muscles were detached from the vertebrae, per normal procedure. Thirteen weeks post-surgery, multifidus and longissimus biopsies at L1, L3 and L5 levels were harvested on the right. From each biopsy, 3 fibers and 3-6 bundles of fibers (∼10-20 fibers ensheathed in their extracellular matrix) were tested mechanically to measure their passive elastic modulus. The collagen content and fatty infiltration of each biopsy were also examined histologically by immunofluorescence staining. Nonparametric statistical methods were used with a 1.25% level of significance.Results: 220 fibers and 279 bundles of fibers were tested. The elastic moduli of the multifidus and longissimus fibers and longissimus fiber bundles were not significantly different between the SI and sham groups. However, the elastic modulus of multifidus fiber bundles was significantly greater in the SI group compared to sham (SI median 82 kPa, range 23-284; sham median 38 kPa, range 23-50, p = 0.0004). The elastic modulus of multifidus fiber bundles in the SI group was not statistically different between spinal levels (p = 0.023). For histology, only collagen I deposition in multifidus was significantly greater in the SI group (median 20.8% vs. 5.8% for sham, p < 0.0001).Conclusions: The surgical injury increased the passive stiffness of the multifidus fiber bundles. Increased collagen content in the extracellular matrix is the likely reason and these changes may be important in the post-operative compensation of the spine.Level Of Evidence: N/A. [ABSTRACT FROM AUTHOR]

Study Design: Observational multicenter study.Objective: The aim of this study was to evaluate changes in pain during sexual activity after surgery for lumbar spinal stenosis (LSS).Summary Of Background Data: There are limited data available on sexual function in patients undergoing surgery for LSS.Methods: Data were retrieved from the Norwegian Registry for Spine Surgery. The primary outcome was change in pain during sexual activity at 1 year, assessed by item number eight of the Oswestry disability index questionnaire. Secondary outcome measures included Oswestry Disability Index, EuroQol-5D, and numeric rating scale scores for back and leg pain.Results: Among the 12,954 patients included, 9908 (76.5%) completed 1-year follow-up. At baseline 9579 patients (73.9%) provided information about pain during sexual activity, whereas 7424 (74.9%) among those with complete follow-up completed this item. Preoperatively 2528 of 9579 patients (26.4%) reported a normal sex-life without pain compared with 4294 of 7424 patients (57.8%) at 1 year. Preoperatively 1007 (10.5%) patients reported that pain prevented any sex-life, compared with 393 patients (5.3%) at 1 year. At baseline 7051 of 9579 patients (73.6%) reported that sexual activity caused pain, and among these 3145 of 4768 responders (66%) reported an improvement at 1 year. A multivariable regression analysis showed that having a life partner, college education, and working until time of surgery were predictors of improvement in pain during sexual activity. Current tobacco smoking, pain duration >12 months, previous spine surgery, and complications occurring within 3 months were negative predictors.Conclusion: This study clearly demonstrates that a large proportion of patients undergoing surgery for LSS experienced an improvement in pain during sexual activity at 1 year.Level of Evidence: 2. [ABSTRACT FROM AUTHOR]

Study Design: Systematic review and meta-analysis.Objective: The purpose of the study was to compare the outcomes and after spinal fusion with or without iliac screw (IS) insertion for patients with adult spinal deformity (ASD).Summary Of Background Data: The number of patients undergoing multilevel spinal stabilization for the treatment of ASD is growing. However, the selection of spinopelvic fixation for ASD patients with long fusion is controversial.Methods: A comprehensive literature search was performed without time restriction according to the guidelines from the Cochrane Collaboration in May 2020 using PubMed, EMBASE, and the Cochrane Library. The comparison of the two types of fixation was evaluated by spinopelvic parameters, incidence rate of complications, rate of revision, and clinical outcomes at the last follow-up.Results: The literature search identified 422 records, of which eight studies were included for meta-analysis with a total of 439 patients. All the included studies provided level III evidence. There was no significant difference in the sagittal vertical axis, pelvic incidence, the proximal junctional kyphosis rates, the pseudarthrosis rates, the revision rates, and the clinical outcomes at the last follow-up between those who receive sacrum fixation and sacropelvic fixation. Nevertheless, greater lumbar lordosis (LL) (weighted mean difference [WMD], 4.15; 95% confidence interval [CI] 2.46-5.84, P < 0.01), greater sacral slope (SS) (WMD, 2.32; 95% CI 1.21-3.43, P < 0.01), and lower rate of the distal instrumentation instability (odds ratio, 0.25; 95% CI 0.10-0.61, P = 0.002) were observed in IS group between the comparison.Conclusion: The clinical outcomes in the IS group were similar to those in the non-IS group, but the application of the IS significantly restored LL, prevented decompensation, and reduced the occurrence of the distal instrumentation instability. Therefore, the IS may be a good choice for the operative treatment of ASD patients with sagittal malalignment and other risks of lumbosacral fracture, metal breakage, and screw pullout.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]