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PURPOSE: To evaluate proximal junctional biomechanics of a MLSS relative to traditional pedicle screw fixation at the proximal extent of T10-pelvis posterior instrumentation constructs (T10-p PSF). METHODS: A previously validated three-dimensional osseoligamentous spinopelvic finite element (FE) model was used to compare proximal junctional range-of-motion (ROM), vertebral body stresses, and discal biomechanics between two groups: (1) T10-p with a T10-11 MLSS (T10-11 MLSS) and (2) T10-p with a traditional T10 pedicle screw (Traditional T10-PS). RESULTS: The T10-11 MLSS had a 5% decrease in T9 cortical bone stress compared to Traditional T10-PS. Conversely, the T10 and T11 bone stresses increased by 46% and 98%, respectively, with T10-11 MLSS compared to Traditional T10-PS. Annular stresses and intradiscal pressures (IDP) were similar at T9-T10 between constructs. At the T10-11 disc, T10-11 MLSS decreased annular stresses by 29% and IDP by 48% compared to Traditional T10-PS. Adjacent ROM (T8-9 & T9-10) were similar between T10-11 MLSS and Traditional T10-PS. T10-11 MLSS had 39% greater ROM at T10-11 and 23% less ROM at T11-12 compared to Traditional T10-PS. CONCLUSIONS: In this FE analysis, a T10-11 MLSS at the proximal extent of T10-pelvis posterior instrumentation resulted in increased T10 and T11 cortical bone stresses, decreased discal annular stress and IDP and increased ROM at T10-11, and no change in ROM at the adjacent level. Given the complex and multifactorial nature of proximal junctional kyphosis, these results require additional biomechanical and clinical evaluations to determine the clinical utility of MLSS on the proximal junctions of thoracolumbar posterior instrumented fusions.

PURPOSE: There is limited information on the clustering or co-occurrence of complications after spinal fusion surgery for neuromuscular disease in children. We aimed to identify the frequency and predictive factors of co-occurring perioperative complications in these children. METHODS: In this retrospective database cohort study, we identified children (ages 10-18 years) with neuromuscular scoliosis who underwent elective spinal fusion in 2012-2020 from the National Surgical Quality Improvement Program-Pediatric database. The rates of co-occurring complications within 30 days were calculated, and associated factors were identified by logistic regression analysis. Correlation between a number of complications and outcomes was assessed. RESULTS: Approximately 11% (709/6677 children with neuromuscular scoliosis undergoing spinal fusion had co-occurring complications: 7% experienced two complications and 4% experienced ≥ 3. The most common complication was bleeding/transfusion (80%), which most frequently co-occurred with pneumonia (24%) and reintubation (18%). Surgical time ≥ 400 min (odds ratio (OR) 1.49 [95% confidence interval (CI) 1.25-1.75]), fusion ≥ 13 levels (1.42 [1.13-1.79]), and pelvic fixation (OR 1.21 [1.01, 1.44]) were identified as procedural factors that independently predicted concurrent complications. Clinical risk factors for co-occurring complications included an American Society of Anesthesiologist physical status classification ≥ 3 (1.73 [1.27-2.37]), structural pulmonary/airway abnormalities (1.24 [1.01-1.52]), impaired cognitive status (1.80 [1.41-2.30]), seizure disorder (1.36 [1.12-1.67]), hematologic disorder (1.40 [1.03-1.91], preoperative nutritional support (1.34 [1.08-1.72]), and congenital malformations (1.20 [1.01-1.44]). Preoperative tracheostomy was protective against concurrent complications (0.62 [0.43-0.89]). Significant correlations were found between number of complications and length of stay, non-home discharge, readmissions, and death. CONCLUSION: Longer surgical time (≥ 400 min), fusion ≥ 13 levels and pelvic fixation are surgical risk factors independently associated with co-occurring complications, which were associated with poorer patient outcomes. Recognizing identified nonmodifiable risk factors might also be important for preoperative planning and risk stratification of children with neuromuscular scoliosis requiring spinal fusion. LEVEL OF EVIDENCE: Level IV evidence.

PURPOSE: The purpose of this review was to evaluate the effectiveness of patient-specific rods for adult spinal deformity. METHODS: A systematic review of the literature was performed through an electronic search of the PubMed, Scopus, and Web of Science databases. Human studies between 2012 and 2023 were included. Sample size, sagittal vertical axis (SVA), pelvic incidence-lumbar lordosis (PI-LL), pelvic tilt (PT), operation time, blood loss, follow-up duration, and complications were recorded for each study when available. RESULTS: Seven studies with a total of 304 adult spinal deformity patients of various etiologies were included. All studies reported SVA, and PT; two studies did not report PI-LL. Four studies reported planned radiographic outcomes. Two found a significant association between preoperative plan and postoperative outcome in all three outcomes. One found a significant association for PI-LL alone. The fourth found no significant associations. SVA improved in six of seven studies, PI-LL improved in all five, and three of seven studies found improved postoperative PT. Significance of these results varied greatly by study. CONCLUSION: Preliminary evidence suggests potential benefits of PSRs in achieving optimal spino-pelvic parameters in ASD surgery. Nevertheless, conclusions regarding the superiority of PSRs over traditional rods must be judiciously drawn, given the heterogeneity of patients and study methodologies, potential confounding variables, and the absence of robust randomized controlled trials. Future investigations should concentrate on enhancing preoperative planning, standardizing surgical methodologies, isolating specific patient subgroups, and head-to-head comparisons with traditional rods to fully elucidate the impact of PSRs in ASD surgery.

BACKGROUND: Lumbar spinal fusion surgery is a well-established treatment for various spinal disorders. However, one of its complications, pseudoarthrosis, poses a significant concern. This study aims to explore the incidence, time and predictive factors contributing to pseudoarthrosis in patients who have undergone lumbar fusion surgery over a 10-year period. METHODS: Data for this research was sourced from the PearlDiver database where insurance claims of patients who underwent multilevel lumbar spinal fusion between 01/01/2010 and 10/31/2022 were examined for claims of pseudoarthrosis within the 10 years of their index procedure. A variety of demographic, comorbid, and surgical factors were assessed, including age, gender, Elixhauser Comorbidity Index (ECI), surgical approach, substance use disorders and history of spinal disorders. Statistical analyses, including chi-squared tests, multivariate analysis, and cox survival analysis were employed to determine significant associations. RESULTS: Among the 76,337 patients included in this retrospective study, 2.70% were diagnosed with symptomatic lumbar pseudoarthrosis at an average of 7.38 years in a 10-year follow-up. Multivariate and Cox hazard analyses revealed that significant predictors of symptomatic pseudoarthrosis development following multilevel primary lumbar fusion include vitamin D deficiency, osteoarthritis, opioid and NSAID use, tobacco use, and a prior history of congenital spine disorders. CONCLUSIONS: In summary, this study revealed a 2.70% incidence of symptomatic lumbar pseudoarthrosis within 10 years of the index procedure. It highlighted several potential predictive factors, including comorbidities, surgical approaches, and substance use disorders, associated with the development of symptomatic pseudoarthrosis. Future research should focus on refining our understanding of these factors to improve patient outcomes and optimize healthcare resource allocation.

Background: Posterolateral decompression and fusion with internal fixation is a commonly used surgical approach for treating degenerative lumbar spinal stenosis (DLSS). This study aims to evaluate the impact of preserving a portion of the unilateral facet joint during decompression on surgical outcomes and long-term recovery in patients. Methods: This study analyzed 73 patients with DLSS accompanied by bilateral lower limb neurological symptoms who underwent single-level L4/5 posterolateral decompression and fusion surgery from January 2022 to March 2023. Patients were categorized into two groups based on the type of surgery received: Group A comprised 31 patients who underwent neural decompression without facet joint preservation, while Group B consisted of 42 patients who underwent neural decompression with preservation of partial facet joints on one side. Regular follow-up evaluations were conducted, including clinical and radiological assessments immediately postoperatively, and at 3 and 12 months thereafter. Key patient information was documented through retrospective chart reviews. Results: Most patients in both groups experienced favorable surgical outcomes. However, four cases encountered complications. Notably, during follow-up, Group B demonstrated superior 1-year postoperative interbody fusion outcomes (P < 0.05), along with a trend towards less interbody cage subsidence and slower postoperative intervertebral disc height loss. Additionally, Group B showed significantly reduced postoperative hospital stay (P < 0.05). Conclusion: Under strict adherence to surgical indications, the posterior lateral lumbar fusion surgery, which preserves partial facet joint unilaterally during neural decompression, can offer greater benefits to patients. [ABSTRACT FROM AUTHOR]

Background: Large spacers offer numerous advantages such as higher fusion rates and lower subsidence rates. However, due to the anatomical constraints of the approach, the use of large spacers in biportal endoscopic transforaminal lumbar interbody fusion(BE-TLIF) necessitates an additional incision and special instruments for spacer implantation leading to less frequent use. Methods: This study has refined several techniques within BE-TLIF. We insert the cage and impact the cage transverse with a special design instrument in the same working portal. This allows for the use of large spacers during BE-TLIF procedures without the need for an auxiliary cage-inserting incision. Conclusion: The technique is a straightforward, safe, and minimally invasive method for inserting large cages in the treatment of lumbar instability. [ABSTRACT FROM AUTHOR]

We describe our protocol and outcomes of awake robotic minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) under spinal anesthesia. We conducted a prospective study of 10 consecutive patients undergoing awake robotic single-level MIS-TLIF with the Mazor X robot. We prospectively collected patient-reported outcomes (back and leg pain visual analog scale and Oswestry Disability Index) preoperatively at 1-month and 1-year follow-ups and assessed fusion and screw placement accuracy with a 1-year computed tomography (CT) scan. Median age was 61 years (interquartile range [IQR] = 57.7–66). Median body mass index was 27 kg/m2. No intraoperative complications were reported. Most (9/10) patients were discharged home, and 50% discharged on the day of surgery. Median length of stay was 16.5 hours (IQR = 5–35.5). Median follow-up was 12.5 months (IQR = 12–13.5), with 9 patients having at least 12-month follow-up, with CT scans documenting good screw placement (Gertzbein-Robbins grade A) and solid bony fusion. Median preoperative back pain visual analog scale score was 7.8 (IQR = 6.9–8) versus 1.5 (IQR = 0–3.2) at 1-month post operation, P < 0.01, and 0 (IQR = 0–1) at 1-year follow-up, P < 0.01; median preoperative leg pain 8 (IQR = 7.4–8) versus 0 (IQR = 0–1.2) at 1-month post operation, P < 0.01, and 0 (IQR = 0–2) at 1-year follow-up, P < 0.01; median preoperative Oswestry Disability Index 47.5 (IQR = 27.8–57.5) versus 4 (IQR = 0–16) at 1-month postoperation, P < 0.01, and 0 (IQR = 0–7) at 1-year follow-up, P < 0.01. Median preoperative disk height of the index level was 8 mm (IQR = 2.4–9.5) versus 11.4 mm (IQR = 9.2–11.2) postoperatively, P < 0.01. Median preoperative lordosis of the index level was 5 degrees (IQR = 3.4–8.5) versus 10.1 degrees (7.3–12.2) postoperatively, P < 0.01. Our study showed significant improvement in patient-reported outcomes at 1-month and 1-year follow-ups after awake robotic MIS-TLIF, as well as solid bony fusion on CT scans. [ABSTRACT FROM AUTHOR]

To reduce the risk of nonunion after spinal fusion surgery, the in situ transplantation of bone marrow mesenchymal stem cells (BMSCs) induced toward osteogenic differentiation by bone morphogenetic protein-2 (BMP2) has been proven effective. However, the current biological agents used for transplantation have limitations, such as a short half-life and low bioavailability. To address this, our study utilized a safe and effective gelatin-methacryloyl (GelMA) as a carrier for BMP2. In vitro, experiments were conducted to observe the ability of this composite vehicle to induce osteogenic differentiation of BMSCs. The results showed that the GelMA hydrogel, with its critical properties and controlled release performance of BMP2, exhibited a slow release of BMP2 over 30 days. Moreover, the GelMA hydrogel not only enhanced the proliferation activity of BMSCs but also significantly promoted their osteogenic differentiation ability, surpassing the BMP2 effects. To investigate the potential of the GelMA-BMP2 composite vehicle, a rabbit model was employed to explore its ability to induce in situ intervertebral fusion by BMSCs. Transplantation experiments in rabbits demonstrated the effective induction of intervertebral bone fusion by the GelMA-BMP2-BMSC composite vehicle. In conclusion, the GelMA-BMP2-BMSC composite vehicle shows promising prospects in preclinical translational therapy for spinal intervertebral fusion. It addresses the limitations of current biological agents and offers a controlled release of BMP2, enhancing the proliferation and osteogenic differentiation of BMSCs. [ABSTRACT FROM AUTHOR]

Background: To compare the clinical and radiological outcomes of modified mini-open transforaminal lumbar interbody fusion (mMO-TLIF) via posterior midline incision for "targeted limited dissection" versus minimal invasive transforaminal lumbar interbody fusion (MIS-TLIF) via Wiltse approach in lumbar degenerative diseases. Methods: A total of 60 consecutive patients in our center from January 2019 to March 2020 were enrolled, including 30 patients who were treated with mMO-TLIF via posterior midline incision and 30 treated with MIS-TLIF through the Wiltse approach. Perioperative parameters were recorded. The questionnaires of Oswestry Disability Index (ODI) and Visual Analogue Score (VAS) were conducted before the operation and after the operation (3 days, 1 week, and 2 years). CT and MRI radiological outcomes were evaluated before the operation and at a 2-year follow-up. Results: There were no significant differences in the general data, gender, age, and BMI between the two groups. All patients were successfully operated without intraoperative complications. There were significant differences between the two groups in the operation time (p < 0.001) and intraoperative bleeding (p < 0.05). There was no difference in ODI and VAS scores between groups pre- and post-operatively, but they were both significantly improved compared to those before the operation (p < 0.01). At a 2-year follow-up, the paraspinal muscle atrophy and fat infiltration were increased comparing to pre-operation, but the difference was also not statistically significant (p > 0.05). In addition, both the two groups' fusion rates were more than 90% at a 2-year follow-up, however, no difference was detected between the two groups. Conclusion: mMO-TLIF via midline incision for "targeted limited dissection" could achieve similar clinical and radiological outcomes as MIS-TLIF for lumbar degenerative disease. [ABSTRACT FROM AUTHOR]

Improvements in spinal fusion devices and techniques have enabled stronger spinal fusion, resulting in excellent clinical outcomes. Nevertheless, complications associated with implants, such as screw misalignment, screw lubrication, cage dislocation, and skin issues, might occur. This study aimed to investigate the characteristics and symptoms of sacral fractures after spinal instrumented fusion. This case series retrospectively examined the medical records of eight patients (one man and seven women; mean age: 74 years) diagnosed with sacral fractures after undergoing posterior spinal instrumented fusion from February 2015 to March 2022. The average number of fusion levels in all patients was 3.5 (range, 1–10). The lowest instrumented vertebrae (LIV) ranged from L5 to the ilium. Sacral fractures were diagnosed at 18.8 (range, 0.5–84) months postoperatively. The average time from consultation to diagnosis was nine days (range, 0–25 days). Two patients had subclinical fractures, two had H-shaped fractures with the LIV at L5, and four had U-shaped fractures, including screw holes. Buttock pain and lower extremity pain, the most commonly reported symptoms, were observed in seven patients each. There were also instances of leg numbness, muscle weakness, and unilateral leg pain that may be related to L5 or S1 radiculopathy. In all patients, leg and buttock pain were worse during movement and in the sitting position, and better while resting and in the supine position. Three patients were treated conservatively, and five were treated with extended fixation to the ilium. Sacral fractures following posterior spinal fusion can cause radiculopathy and buttock pain. Symptoms are especially severe when instability occurs in the pelvic region, such as during movements or sitting. As atypical radiculopathy may lead to delays in diagnosis, spine surgeons should recognize the symptoms of this condition. [ABSTRACT FROM AUTHOR]

Study Design. Retrospective cohort. Objective. Examine the relationship between compensatory pelvic retroversion, positive sagittal imbalance (measured by C2 tilt), and the C2 pelvic angle (C2PA) in patients before long spinal fusions; and to determine the association between changes in C2PA and pelvic tilt (PT) following long spinal fusions. Background. Adult spinal deformity surgical goals often include a PT target, yet patients frequently demonstrate persistent compensatory pelvic retroversion following surgery. Methods. Adults above 18 years old undergoing long spinal fusions (> 4 levels) with standing preoperative and postoperative radiographs were included. To examine drivers of preoperative sagittal balance, regression models were fit to estimate the association between preoperative C2PA and pelvic incidence with preoperative PT and C2 tilt. To predict postoperative change in PT, multivariable regression was used to estimate change in PT, adjusting for change in C2PA and preoperative C2 tilt. Results. Among the 80 patients identified, the median age was 61 (IQR: 45-72) and 46 (58%) were female. The median number of levels fused was 10 (IQR: 8-13) and 55 (69%) were instrumented to the sacrum/pelvis. Preoperative C2PA had a significant nonlinear association with preoperative PT (r2=0.81, P<0.001) and preoperative C2 tilt (r2= 0.41, P= 0.002). Postoperative change in PT was strongly associated with change in C2PA (β=0.81; P<0.001) and preoperative C2 tilt (β= 0.55; P< 0.001). Conclusions. Following long spinal fusions, change in PT (or lack thereof) can be reliably predicted based on change in C2PA and preoperative C2 tilt. In patients with normal preoperative C2 tilt, the change in C2PA is nearly equivalent to the change in PT, but in patients with more positive C2 tilt (sagittal imbalance), a greater change in C2PA will be required to achieve an equivalent change in PT. [ABSTRACT FROM AUTHOR]

Study Design. Experimental porcine anterior cervical discectomy and fusion (ACDF) model: a proof-of-concept study. Objective. The effect of monetite synthetic bone graft (SBG) containing calcium pyrophosphate and ß-tricalcium phosphate on cervical spinal fusion in a noninstrumented two-level large animal model. Summary of Background Data. ACDF is the gold standard surgical technique for the treatment of degenerative cervical spinal diseases. However, pseudarthrosis associated with increased patient morbidity occurs in ~2.6% of the surgeries. SBG may enhance bony fusion and subsequently decrease the risk of pseudarthrosis. Recent studies on monetite-based SBGs for use in large cranial defects in humans have shown promising bone healing results, necessitating further investigation of their use in cervical spinal fusion. Materials and Methods. Four adult female Danish Göttingen minipigs received partial cervical anterior discectomy and intervertebral defects at an upper and lower level. One defect was filled with SBG, and the other was left empty. Bony fusion was evaluated using computed tomography (CT) at three-month intervals for 12 months. Fifteen months postsurgery, the animals were euthanized for further ex vivo qualitative histopathologic and micro-CT evaluations. Fusion rates were compared using the Fisher exact test at each time point. Results. Increased interbody bony fusion rates were observed at SBG levels (4/4) compared with control levels (0/4) evaluated by CT at 6 and 9 months postsurgery (P=0.029). Fusion was observed at all SBG levels 12 months postsurgery and at only one control level. Histopathologic evaluation confirmed high-quality interbody bony fusion at all SBG levels and fusion by spondylosis at one control level. Conclusion. This proof-of-concept study provides preliminary evidence of a novel, calcium pyrophosphate-containing, and ß-tricalcium phosphate-containing monetite SBG that promotes bony fusion compared with a negative control in a clinically relevant porcine model of ACDF. [ABSTRACT FROM AUTHOR]

Study Design. Retrospective analysis of prospectively collected data. Objective. Evaluate the impact of correcting normative segmental lordosis values on postoperative outcomes. Background. Restoring lumbar lordosis magnitude is crucial in adult spinal deformity surgery, but the optimal location and segmental distribution remain unclear. Patients and Methods. Patients were grouped based on offset to normative segmental lordosis values, extracted from recent publications. Matched patients were within 10% of the cohort's mean offset, less than or over 10% were undercorrected and overcorrected. Surgical technique, patient-reported outcome measures, and surgical complications were compared across groups at baseline and two years. Results. In total, 510 patients with a mean age of 64.6, a mean Charlson comorbidity index 2.08, and a mean follow-up of 25 months. L4-5 was least likely to be matched (19.1%), while L4-S1 was the most likely (24.3%). More patients were overcorrected at proximal levels (T10-L2; undercorrected, U: 32.2% vs. matched, M: 21.7% vs. overcorrected, O: 46.1%) and undercorrected at distal levels (L4-S1: U: 39.0% vs. M: 24.3% vs. O: 36.8%). Postoperative Oswestry disability index was comparable across correction groups at all spinal levels except at L4-S1 and T10-L2/L4-S1, where overcorrected patients and matched were better than undercorrected (U: 32.1 vs. M: 25.4 vs. O: 26.5, P=0.005; U: 36.2 vs. M: 24.2 vs. O: 26.8, P=0.001; respectively). Patients overcorrected at T10-L2 experienced higher rates of proximal junctional failure (U: 16.0% vs. M: 15.6% vs. O: 32.8%, P<0.001) and had greater posterior inclination of the upper instrumented vertebrae (U: -9.2±9.4° vs. M: -9.6±9.1° vs. O: -12.2±10.0°, P<0.001), whereas undercorrection at these levels led to higher rates of revision for implant failure (U: 14.2% vs. M: 7.3% vs. O: 6.4%, P=0.025). Conclusions. Patients undergoing fusion for adult spinal deformity suffer higher rates of proximal junctional failure with overcorrection and increased rates of implant failure with undercorrection based on normative segmental lordosis. [ABSTRACT FROM AUTHOR]

The opioid epidemic is a public health crisis affecting spine care and pain management. Medical marijuana is a potential nonopioid analgesic yet to be studied in the surgical setting since its effects on bone healing are not fully understood. Studies have demonstrated analgesic and potentially osteoinductive properties of cannabinoids with endocannabinoid receptor expression in bone tissue. We hypothesize that tetrahydrocannabinol (THC) and cannabidiol (CBD) will not decrease bone healing in spinal fusion. Seventy-eight adult Sprague-Dawley rats were used for this study. Utilizing allogenic bone grafts (6 donor rats), posterolateral inter-transverse lumbar fusion at the L4–L5 level was performed. The animals were equally divided into four treatment groups, each receiving 0.1 ml intraperitoneal injections weekly as follows: placebo (saline), 5 mg/kg THC, 5 mg/kg CBD, and a combination of 5 mg/kg THC and 5mg/kg CBD (Combo). Callus tissue was harvested 2- and 8-weeks postsurgery for qPCR assessment to quantify changes in the expression of osteogenic genes. Manual palpation was done to assess the strength of the L4–L5 arthrodesis on all rats. μCT image-based callus analysis and histology were performed. One-way ANOVA followed by post hoc comparisons was performed. μCT demonstrated no significant differences. Treatment groups had slightly increased bone volume and density compared to control. qPCR at 2 weeks indicated downregulated RANKL/OPG ratios skewing towards osteogenesis in the CBD group, with the THC and CBD+THC groups demonstrating a downward trend (p>.05). ALPL, BMP4, and SOST were significantly higher in the CBD group, with CTNNB1 and RUNX2 also showing an upregulating trend. The CBD group showed elevation in Col1A1 and MMP13. Data at eight weeks showed ALPL, RUNX2, BMP4, and SOST were downregulated for all treatment groups. In the CBD+THC group, RANK, RANKL, and OPG were downregulated. OPG downregulation reached significance for the THC and CBD+THC group compared to saline. Interestingly, the RANKL/OPG ratio showed upregulation in the CBD and CBD+THC groups. RANKL showed upregulation in the CBD group. At 2 and 8 weeks, the CBD treatment group showed superior histological progression, increasing between time points. This study demonstrates that CBD and THC have no adverse effect on bone healing and the rate of spinal fusion in rats. Osteogenic factors were upregulated in the CBD-treated groups at 2 weeks, which indicates a potential for bone regeneration. In this group, compared to control, the RANKL/OPG ratio at the early healing phase demonstrates the inhibition of osteoclast differentiation, enhancing bone formation. Interestingly, it shows promoted osteoclast differentiation at the later healing phase, enhancing bone remodeling. This aligns with the physiological expectation of a lower ratio in the early phases and a higher ratio in the later remodeling phases. CBD and THC showed no inhibitory effects on bone healing in a spinal fusion model. Moreover, histologic and gene expression analysis demonstrated that CBD may, in fact, enhance bone healing. Further research is needed to confirm the safe usage of THC and CBD in the postoperative setting following spinal fusions. [ABSTRACT FROM AUTHOR]

Transcranial Motor Evoked Potentials (TcMEPs) can improve intraoperative detection of femoral plexus and nerve root injury during lumbosacral spine surgery. However, even under ideal conditions, TcMEPs are not completely free of false-positive alerts due to the immobilizing effect of general anesthetics, especially in the proximal musculature. The application of transcutaneous stimulation to activate ventral nerve roots directly at the level of the conus medularis (bypassing the brain and spinal cord) has emerged as a method to potentially monitor the motor component of the femoral plexus and lumbosacral nerves free from the blunting effects of general anesthesia. To evaluate the reliability and efficacy of transabdominal motor evoked potentials (TaMEPs) compared to TcMEPs during lumbosacral spine procedures. We present the findings of a single-center 12-month retrospective experience of all lumbosacral spine surgeries utilizing multimodality intraoperative neuromonitoring (IONM) consisting of TcMEPs, TaMEPs, somatosensory evoked potentials (SSEPs), electromyography (EMG), and electroencephalography. Two hundred and twenty patients having one, or a combination of lumbosacral spine procedures, including anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (LLIF), posterior spinal fusion (PSF), and/or transforaminal lumbar interbody fusion (TLIF). Intraoperative neuromonitoring data was correlated to immediate postoperative neurologic examinations and chart review. Baseline reliability, false positive rate, true positive rate, false negative rate, area under the curve at baseline and at alerts, and detection of preoperative deficits of TcMEPs and TaMEPs were compared and analyzed for statistical significance. The relationship between transcutaneous stimulation voltage level and patient BMI was also examined. TaMEPs were significantly more reliable than TcMEPs in all muscles except abductor hallucis. Of the 27 false positive alerts, 24 were TcMEPs alone, and 3 were TaMEPs alone. Of the 19 true positives, none were detected by TcMEPs alone, 3 were detected by TaMEPs alone (TcMEPs were not present), and the remaining 16 true positives involved TaMEPs and TcMEPs. TaMEPs had a significantly larger area under the curve (AUC) at baseline than TcMEPs in all muscles except abductor hallucis. The percent decrease in TcMEP and TaMEP AUC during LLIF alerts was not significantly different. Both TcMEPs and TaMEPs reflected three preexisting motor deficits. Patient BMI and TaMEP stimulation intensity were found to be moderately positively correlated. These findings demonstrate the high reliability and predictability of TaMEPs and the potential added value when TaMEPs are incorporated into multimodality IONM during lumbosacral spine surgery. [ABSTRACT FROM AUTHOR]

Long-segment pedicle screw instrumentation is widely used to treat complex spinal disorders. Rods are routinely precontoured to maximize assistance on the correcting side of the deformity, but there often exists a residual gap discrepancy between the precontoured rods and screw tulips. No previous research has investigated the diminished pullout strength of the most proximal or distal pedicle screw resulting from a mismatched rod in long-segment pedicle screw instrumentation. The present study aimed to investigate the decreased pullout force of pedicle screws affected by the gap discrepancy when forcefully engaging a mismatched rod into a tulip in a normal-density porcine spine. The pedicle screw fixation strength under axial pullout force was compared among three different gap discrepancies between rods and tulips using long porcine spine segments. Twelve porcine lumbar vertebrae (L3–L6) were implanted with pedicle screws and rods. Screws on one side had no gap between the tulip and rod (0-mm group), while the most proximal screw on the other side had an intentional gap of 3 mm (3-mm group) or 6 mm (6-mm group). Three hours after forcefully engaging the rod into the tulips at room temperature, the set screws in all specimens were loosened, and each specimen was dissected into individual vertebrae for subsequent pullout testing. The control group exhibited significantly greater pullout strength (1987.68 ± 126.80 N) than the groups from different rod-tulip configurations (p<.05), with significantly greater strength in the 3-mm group (945.62 ± 97.43 N) than the 6-mm group (655.30 ± 194.49 N) (p<.05). Only 47.6% and 33.0% of the pullout strength was retained in the 3-mm and 6-mm groups, respectively, compared to the control group. Gap discrepancies between rods and tulips can significantly reduce pedicle screw pullout strength, with a correlation between decreased strength and increased gaps. Surgeons should avoid forcefully engaging mismatched rods and consider well-fitted contoured rods in spinal surgery to minimize the risk of screw loosening. The gap discrepancy between rod and tulip significantly affected pullout strength, with greater gaps leading to reduced strength. Forcefully engaging mismatched rods into tulips in degenerative spinal surgery should be avoided to minimize the risk of early screw pullout. [ABSTRACT FROM AUTHOR]

Objective: To explore the feasibility of applying CT Hounsfield Units (HUs) for the assessment of preoperative paraspinal muscle fat infiltration (FI) in different segments in patients who underwent anterior cervical discectomy and fusion (ACDF). To compare the consistency of preoperative paraspinal muscle FI evaluations using MRI and those via CT HUs in patients who underwent ACDF surgery. Methods: Ninety-five patients (45 males and 50 females, aged 37‒71 years) who received CT and MRI examinations and underwent ACDF surgery were retrospectively analyzed. In the axial T2-weighted MR images at the median level of the C3/4, C4/5, and C5/6 segments, regions of interests (ROIs) were delineated along the boundaries of the cervical multifidus (MF) and semispinalis cervicis (Scer) muscles. Using the threshold tool in ImageJ software, areas of fat tissue and intermuscular septa within the ROI were quantified. The effective cross-sectional area (ECSA) for each side was obtained by subtracting the areas of fat tissue and intermuscular septa from the total ROI area. The ratio of the fat tissue area to the CSA was then calculated to determine the initial FI value. The depth of subcutaneous fat from the midline spinous process to the epidermis at the median plane of the C4/5 intervertebral disc was measured. The initial FI values were then divided by the depth of fat to determine the post-correction FI value. Using the Picture Archiving and Communication System (PACS), at identical segments and planes, ROIs were delineated using the same method as in MRI under a standard soft tissue window (width of 500 HU, level of 60 HU). The CT HU values were measured within these defined areas. The CT HU values from both sides are summed to obtain the total HU value for the segment. According to whether the measurement results of two sets of data follow a normal distribution, Pearson's test or Sperman's test was used to analyze the correlation. Results: On MRI, a statistically significant difference was observed in the post-correction FI only at the C3/4 segment compared to the other two segments (P < 0.05). No significant difference in the post-correction FI between the C4/5 and C5/6 segments was noted (P > 0.05). The CT HU results showed a substantial discrepancy between C3/4 and C4/5 segments and between C3/4 and C5/6 segments (P < 0.05), whereas no statistically significant difference was found in the CT HU value between the C4/5 and C5/6 segments (P > 0.05). The consistency analysis revealed a relatively strong correlation between the post-correction FI and CT HU values of the C3/4 and C4/5 segments. Furthermore, a strong correlation was detected in the variations in the measurement outcomes at the C5/6 segment. Conclusion: Patients requiring surgical treatment for the cervical spine exhibit varying degrees of FI in paraspinal muscles across different locations and segments. Evaluating the degree of FI in the paraspinal muscles of the cervical spine through CT HU values is feasible. There is considerable consistency between the post-correction FI assessed under MRI and the measurements of CT HU values in evaluating the FI of paraspinal muscles in the cervical spine. [ABSTRACT FROM AUTHOR]

Objective: As there are no substantial selection criteria for determining the lowest instrumented vertebra (LIV) in adolescent idiopathic scoliosis (AIS) Lenke 5C/6C, thus, many surgeons base their selection on experience. The study aims to compare the selection of the lowest instrumented vertebrae (LIV) lumbar vertebra three (L3) with the use of direct vertebrae rotation (DVR) to the lowest instrumented vertebrae (LIV) lumbar vertebra four (L4) with the use of non-DVR for the correction of adolescent idiopathic scoliosis (AIS) Lenke 5C/6C when the lower end vertebrae (LEV) is at lumbar vertebrae four (L4). Methods: This prospective study involved 101 patients who were divided into two groups based on different techniques. The patients were prospectively followed up for at least four years. All patients included in the study had a lower end vertebra (LEV) at L4, while patients older than 18 years and patients with prior surgical procedures were excluded. The DVR group consisted of 49 patients, and the non-DVR group included 51 patients. Results: The preoperative mean LIV disc angle was 3.1 ± 3 and 3.1 ± 1, P = 0.097, which corrected to 1.2 ± 0 and 1.1 ± 0 in both groups at 4-year follow-up without statistical significance. The LIVDA and LIVT were statistically insignificant at the preoperative, and there were no significant differences at the follow-up visitation. The DVR group achieved a satisfactory coronal and Cobb's angle correction compared to the NDVR group; however, there were no statistical differences at the follow-up visitations. Both groups achieve a satisfactory correction rate without substantial significance in clinical and radiological outcomes. Furthermore, no post-surgical complications were recorded in either group. Conclusions: DVR is suitable for selecting L3 as the LIV in AIS Lenke 5C/6C compared to L4 in non-DVR. DVR preserved more segments without substantial complications during the follow-up visitations. Nevertheless, both groups will continue to be followed up to prevent adding-on post-surgical complications. [ABSTRACT FROM AUTHOR]

Introduction: Lumbar spine fixation and fusion is currently performed with intraoperative tools such as intraoperative CT scan integrated to navigation system to provide accurate and safe positioning of the screws. The use of microscopic visualization systems enhances visualization and accuracy during decompression of the spinal canal as well. Methods: We introduce a novel setting in microsurgical decompression and fusion of lumbar spine using an exoscope with robotized arm (RoboticScope) interfaced with navigation and head mounted displays. Conclusion: Spinal canal decompression and fusion can effectively be performed with RoboticScope, with significant advantages especially regarding ergonomics. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective cohort study. Objectives: Effects of blood loss that requires blood transfusion after lumbar spinal fusion remain an important issue. Blood transfusions are used commonly in cases of significant blood loss in lumbar spinal fusion but are associated with adverse effects. The objective was to assess the rate of blood transfusion and the associated risk after lumbar spinal fusion from 2013 to 2018. Methods: In this nationwide population-based cohort study, the Korean Health Insurance Review and Assessment Service database was reviewed retrospectively from 2013 to 2018. Data were extracted from patients who underwent lumbar spinal fusion without history of lumbar spinal surgery in the preceding year. The primary outcome was the rate of blood transfusion within 1 week of surgery. In addition, the risk factors for blood transfusion and the rate of postoperative infection were evaluated. Results: A total of 188,581 patients underwent lumbar spinal fusion between 2013 and 2018. A significant decline in blood transfusions was observed during the study period (56.38–47.51%). The presence of comorbidities was associated with an increased risk of blood transfusion. Patients who underwent the posterior approach were more likely to receive blood transfusion than patients who underwent the anterior or anterior and posterior approach. Receiving blood transfusion was associated with postoperative infection. Conclusions: In the present study, the prevalence, risk factors, and postoperative infection rates associated with blood transfusion in lumbar spinal fusion were identified. Spine surgeons should consider these risk factors in patients at high risk of blood transfusion. [ABSTRACT FROM AUTHOR]

Background: Severe spinal deformity manifests as a pronounced deviation from the normal curvature of the spine in the frontal, sagittal, and horizontal planes, where the coronal plane curvature exceeds 90 degrees and may coincide with hyperkyphotic deformity. The most severe deformities exhibit rigidity, with flexibility below 30%. If left untreated or improperly treated, these deformities can result in serious complications associated with progression of the curvature. A combination of surgical techniques is frequently employed to attain optimal outcomes and minimize the risk of complications. The overall medical condition of the patient, their capacity to endure extensive procedures, the expertise of the surgeon, and the resources available all play significant roles in determining the course of management. A systematic and thorough review of the relevant literature was conducted utilizing a variety of electronic databases. The primary objective of this study was to scrutinize the surgical techniques commonly employed in complex spine surgeries for the management of severe scoliosis without resection vertebral body techniques, with higher potential risk of major complications, including permanent neurological deficit. Conclusions: Halo-gravity traction, halo femoral traction, and all techniques for releases of the spine (anterior, posterior, or combine), as well as thoracoplasty, have demonstrated significant effectiveness in managing severe and rigid idiopathic scoliosis. The combination of several of these methods can lead to optimal alignment correction without the need to perform high-risk techniques involving three-column osteotomies. Surgeons must customize the indications based on factors such as available resources, characteristics of the deformity, and the patient's individual profile. Surgical correction of severe scoliosis without vertebral body resection surgeries decreases the potential risks related to neurological and pulmonary complications while providing significant clinical improvement outcomes. The powerful Ponte osteotomy is indicated for severe scoliosis, curves with poor flexibility, for better restoration of hypokyphosis, and decrease of hyperkyphosis. These corrective techniques combined with HGT or temporary internal distraction rods are recommended as viable options for managing individuals with severe rigid spine deformity characteristics. Therefore, they also should be considered and performed by a proficient surgical team. The presence of neuromonitoring is crucial throughout these procedures. [ABSTRACT FROM AUTHOR]

Study Design. Retrospective cohort study. Objective. To compare outcomes in anteriorly placed transforaminal lumbar interbody fusions (TLIFs) and anterior lumbar interbody fusions (ALIFs). Summary of Background Data. TLIF and ALIF are surgical techniques that have become more prevalent in recent years. Although studies have compared the two, none have considered TLIFs with anteriorly placed cages, which may serve as a better comparison to ALIFs. Patients and Methods. Patients undergoing TLIF or ALIF with posterior instrumentation from 2010 to 2020 at a tertiary care institution were retrospectively identified. TLIF cage position was assessed and those with anterior placement were included. Electronic medical records were reviewed to identify patient characteristics and patient-reported outcomes. Radiographic outcomes included posterior disc height (DH), lumbar lordosis (LL), sacral slope, pelvic incidence, and pelvic tilt. Statistical analysis was performed to compare the two groups. Results. Of the 351 patients, 108 had ALIF with posterior instrumentation and 207 had a TLIF. Preoperatively, patients undergoing TLIF had less LL (53.7° vs. 60.6°, P < 0.001), sacral slope (38.3° vs. 43.7°, P < 0.001), and pelvic incidence (60.1° vs. 66.1°, P < 0.001), all of which remained significant at 1-year and long-term follow-up (P < 0.001). The TLIF group had less ΔDH (1.51° vs. 5.43°, P < 0.001), ΔLL (1.8° vs. 2.97°, P = 0.038), and Δsegmental lordosis (0.18° vs. 4.40°, P < 0.001) at 1 year postoperatively. At 2 to 3 years, ΔDH (P < 0.001) and Δsegmental lordosis (P = 0.001) remained significant, but ΔLL (P = 0.695) did not. Patients in the TLIF group had higher Visual Analog Scale-Back scores 1 year postoperatively (3.68 vs. 2.16, P = 0.008) and experienced less improvement in Oswestry Disability Index (-17.1 vs. -28.6, P = 0.012) and Visual Analog Scale-Back (-2.67 vs. -4.50, P = 0.008) compared with patients undergoing ALIF. Conclusions. Our findings suggest that ALIF with posterior instrumentation performed superiorly in radiographic outcomes and patient-reported outcomes compared with anteriorly placed TLIFs. Anteriorly placed TLIF cages may not achieve the same results as those of ALIF cages. [ABSTRACT FROM AUTHOR]

Problems, such as broken screws, broken rods, and cage subsidence after clinical spinal fusion surgery affect the success rate of fusion surgery and the fixation effect of fusion segments, and these problems still affect the treatment and postoperative recovery of patients. In this study, we used the biomechanical finite element analysis method to analyze and study the fixation effect of three kinds of spinal internal fixation systems on L4–L5 lumbar spine segments in percutaneous endoscopic posterior lumbar interbody fusion (PE-PLIF). The three different fixation systems compared in this study include bilateral pedicle screw fixation (M1); bilateral pedicle screw with cross-link fixation (M2); bilateral pedicle screws with double bent rods fixation (M3). The internal fixation systems with different structures were analyzed with the help of Hypermesh, and Abaqus. It was found that the internal fixation system with double bent rods reduced screw stresses by 23.8 and 22.2% in right and left axial rotation than the traditional bilateral pedicle screw system, while titanium rod stresses were reduced by 9.6, 3.7, 9.6, and 2.9% in flexion, left and right lateral bending, and right axial rotation, respectively, and L5 upper endplate stresses were reduced by 35.5, 18.9, 38.4, 10.2, and 48.3% in flexion, left and right lateral bending, and left and right axial rotation, respectively. The spinal range of motion (ROM) of the M3 internal fixation system was less than that of the M1 and M2 internal fixation systems in left lateral bending, left lateral rotation, and right axial rotation, and the intact vertebral ROM was reduced by 93.7, 94.9, and 90.9%, respectively. The double bent rod structure of the spinal internal fixation system has better biomechanical properties, which can effectively reduce the risk of screw breakage, loosening, cage subsidence, and endplate collapse after fusion surgery. [ABSTRACT FROM AUTHOR]

AbstractPurposeMethodsResultsConclusionsTo investigate the incidence, risk factors, and clinical impact of persistent coronal imbalance (PCI) in Lenke5C adolescent idiopathic scoliosis (AIS) undergoing posterior spinal fusion (PSF).We analyzed the medical records of 112 Lenke5C AIS patients. They were grouped into PCI (+) group and PCI (–) group according to the occurrence of PCI at 2 years after surgery. Coronal and sagittal parameters were measured and compared between both groups preoperatively, immediately postoperatively, and 2 years postoperatively. Scoliosis Research Society-22 (SRS-22) score was used to evaluate clinical outcomes.Of the 112 patients, 12 had coronal imbalance persisting 2 years after surgery. Logistic regression analysis indicated risk factors including older age [odds ratio (OR) = 1.841, 95% confidence interval (CI) = 1.147–2.132, p = .001], lower preoperative flexibility main thoracic (MT) curve (OR = 1.308, 95% CI = 1.041–2.015, p = .016), greater preoperative apical vertebral translation (AVT) of the thoracolumbar/lumbar (TL/L) curve (AVT-TL/L) (OR = 2.291, 95% CI = 1.120–4.719, p = .001), larger preoperative lowest instrumented vertebra tilt (LIV lilt) (OR = 2.141, 95% CI = 1.491–3.651, p = .011), and postoperative immediate coronal imbalance (OR = 5.512, 95% CI = 4.531–6.891, p = .001). The satisfaction and total score of the SRS-22 scale in the PCI (+) group were lower than those in the PCI (–) group at 2 years after surgery (p <.05).We found a 10.7% incidence of PCI in patients with Lenke5C AIS undergoing PSF. PCI adversely affects clinical outcomes. Risk factors of PCI included older age, reduced preoperative MT curve flexibility, increased preoperative AVT in the TL/L curve, greater preoperative LIV tilt, and immediate postoperative coronal imbalance. [ABSTRACT FROM AUTHOR]

Background: Patients with frailty are more prone to have perioperative adverse events, and enhanced recovery after surgery (ERAS) has been widely adopted to improve perioperative outcomes. The purpose of this study was to assess the impact of improved compliance with ERAS on perioperative outcomes in frail patients. Methods: Geriatric patients (over 65 years) who underwent multi-level lumbar fusion surgery between June 2017 and June 2022 were included. The patients were divided into two groups according to their degree of compliance with the ERAS. Stepwise nearest-neighbor propensity score matching 1:1 cohorts for age, gender, body mass index (BMI), American Society of Anesthesiologists (ASA) classfication and Charlson Comorbidity Index (CCI) was performed between groups, namely frail-compliant (FC), frail-noncompliant (FN). Further length of stay (LOS), complications and clinical efficacy were compared between groups. Results: There were 83 pairs of well-balanced patients with comparable clinical baseline data. It was worth noting that patients in FC group has significant lower overall complications (20.5% in the FC group vs 39.8% in the FN group, P = 0.007), major complications (7.2% in the FC group vs 19.3% in the FN group, P = 0.022) and shorter LOS (11.18 ± 5.32 in the FC group vs 14.45 ± 4.68 in the FN group, P < 0.001) than patients in FN group. In addition, the initial occurrence of ambulation (2.14 ± 1.21 in FC group vs 3.18 ± 1.73 in FN group, P = 0.012) and bowel movement (3.68 ± 1.24 in FC group vs 4.17 ± 1.32 in FN group, P = 0.031) were earlier for patients in FC group than patients in FN group. With regard to clinical efficacy, there were no significant difference between FC and FN group in terms of patients who meet minimal clinical important difference (MCID) for Oswestry Disability Index (ODI) at postoperative day (POD) 30, Visual Analog Scale (VAS) for back at POD 30-90 and VAS for legs at POD 30, 90, and 180 follow-up intervals. However, there were significant more patients meeting MCID for ODI at POD 90 and180, and VAS for back at POD 180 between FC and FN group. Conclusions: In this retrospective cohort study, we found that frail patients with higher ERAS adherence group had a lower incidence of overall complication, mjor complications, and a shorter LOS than their lower ERAS adherence counterparts. In addition, frail patients with higher ERAS adherence had earlier ambulatioin and bowel movement. More importantly, we found there were significant more patients meeting MCID for ODI at POD 90 and180, and VAS for back at POD 180 in higher ERAS adherence than their lower counterparts. [ABSTRACT FROM AUTHOR]

Background Case Presentation Conclusions Lumbar spondylolysis is a common cause of low back pain in adolescents. A lot of adolescent idiopathic scoliosis with concomitant spondylolysis has been reported before, but only two cases with acquired spondylolysis following long fusion for scoliosis were reported. We described another similar rare case and discussed its causes and treatment options in this paper.A 17‐year‐old female underwent growing rod implantation, growing rod extension, and final long spinal fusion for idiopathic scoliosis. Then, she suffered from low back pain with a VAS of 1‐2 points and gradually aggravated to a VAS of 7‐8 points at 3.5 years after the final fusion. The X‐ray images showed that there was L4‐S1 instability. And the CT scan images showed new bilateral spondylolysis of L5.These findings suggested that distal mechanical stress might cause spondylolysis of the distal vertebra following long fusion for scoliosis. Surgeons should keep instrumentation as short as possible and avoid choosing a low lumbar as LIV when they decide on the fusion levels. [ABSTRACT FROM AUTHOR]

Background: Lumbar spinal pathology is known to affect outcomes following total hip arthroplasty (THA). However, the effect of hip osteoarthritis (OA) on outcomes following lumbar fusion has not been well studied. The purpose of this study was to determine the association between hip OA and spinal reoperation following lumbar spinal fusion. Methods: The 5% Medicare Part B claims database was queried for all patients who underwent primary elective lumbar fusion from 2005 to 2019. Patients were divided into 2 groups: those who underwent elective THA within 1 year after primary lumbar fusion, indicating that they had severe hip OA at the time of lumbar fusion, and those who underwent lumbar fusion with no diagnosed hip OA and no THA during the study period. Exclusion criteria included THA as a result of trauma, revision THA or primary THA in the 5-year period before primary lumbar fusion, <65 years of age, and no enrollment in the database for 5 years before and 1 year after primary lumbar fusion. The primary outcomewas spinal reoperationwithin 1, 3, and 5 years. Multivariable Cox regression was performed with age, sex, diabetes, heart disease, obesity, smoking status, osteoporosis, number of levels fused, use of posterior instrumentation, use of an interbody device, use of bone graft, and surgical approach as covariates. Results: Overall, 1,123 patients (63.4% female; 91.3% White; mean age, 76.8 ± 4.1 years) were included in the hip OA group and 8,893 patients (56.2% female; 91.3% White; mean age, 74.8 ± 4.9 years) were included in the control group. After multivariable analysis, patients with severe hip OA had significantly greater rates of revision surgery at 3 years (odds ratio [OR], 1.61; p < 0.001) and 5 years (OR, 1.87; p < 0.001) after the index lumbar fusion. Conclusions: Patients with severe hip OA at the time of primary lumbar fusion had a significantly increased risk of spinal reoperation at 3 and 5 years postoperatively. These data provide further evidence to support performing THA prior to lumbar fusion in the unsettled debate regarding which surgery should be prioritized for patients with simultaneous degenerative diseases of the hip and lumbar spine. [ABSTRACT FROM AUTHOR]

Background: A number of studies have yielded disparate findings regarding the relationship between implant density and curve correction in adolescent idiopathic scoliosis (AIS) surgery. This study compared the efficacy and safety of low-density (LD) versus high-density (HD) pedicular screw implants in the correction of deformity in AIS regarding clinical, radiological, and quality of life outcomes. Methods: This study was a single-blind, parallel, randomized trial that enrolled 20 adolescent patients with idiopathic scoliosis scheduled for posterior spinal fusion surgery with all pedicle screw constructs. Patients were randomized into two groups of 10 patients each. The LD group included patients in whom the number of screws per fused spinal level had a density of 1.5 or less, while the HD group had a density greater than 1.5. The primary outcomes were the radiological findings of curve correction. The secondary outcomes included the correlation between implant density and curve correction, the amount of blood loss, operation time, number of screws, fusion level, hospital stay duration, and quality of life assessed by the Scoliosis Research Society 22r questionnaire. Results: Radiologically, the postoperative main curves Cobb angles and their changes were comparable between both approaches without statistical correlation with the implant density (p˃0.05). The LD approach significantly shortened the operative time (p=0.015), number of screws (p=0.011), implant density (p<0.001), and hospital stay (p<0.001). However, quality of life scores before surgery and at final follow-up did not differ between the two techniques (p˃0.05). Conclusions: The use of a low-density approach is an effective and safe methodology for attaining satisfactory deformity correction in AIS patients. Furthermore, this approach confers the additional advantage of reduced operative time, number of screws, implant density, and hospital stay in comparison to the high-density approach. Trial registration Pan African Clinical Trial Registry, PACTR202404611444119. Registered 28 March 2024-Retrospectively registered, https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=29382 [ABSTRACT FROM AUTHOR]