Category: Spine

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Fully Navigated Single-Position Prone Lateral Lumbar Interbody Fusion: A Detailed Technical Report and Description of 15 Cases

Int J Spine Surg 2025, 19 (1) 70-80

Surgical Technique and Study Overview

• Single-position prone lateral lumbar interbody fusion improves surgery efficiency and safety.

• Navigation enhances precision in pedicle screw placement and reduces radiation exposure.

• Study involved 15 patients with simultaneous cage and screw placement using intraoperative navigation.

• Mean surgery duration was 263 ± 94 minutes with blood loss of 315 ± 143 mL.

• No major complications reported, except for two cases of cerebrospinal fluid leakage.

Clinical Outcomes and Findings

• Significant improvements in Oswestry Disability Index (ODI) scores post-surgery (51.38 to 32.81).

• Segmental lordosis improved significantly from 3.26° to 13.09° (P < 0.001).

• No significant changes in total lumbar lordosis or sagittal vertical axis.

Technical Insights and Considerations

• Intraoperative navigation used for cage and screw placement without additional fluoroscopy.

• Radiation exposure reduced for surgical teams due to minimized fluoroscopy use.

• Simultaneous screw and cage placement guided by navigation and neuromonitoring.

• Challenges include navigation system inaccuracies due to segmental distraction.

• Learning curve observed with new workflow implementation affecting time savings.

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Robotic Spine Surgery: Systematic Review of Common Error Types and Best Practices

Operative Neurosurgery 28:295–302, 2025

• Robotic systems enhance accuracy in pedicle screw placement, reducing complications and hospital stays.

• Common errors in robotic spine surgery include registration, skiving, and interference errors.

• Registration errors occur due to imaging discrepancies or unexpected intraoperative movements.

• Skiving errors result from sliding of drilling instruments, often due to poor entry points.

• Interference errors arise from unintended interactions with soft tissue or robotic system malfunctions.

• Best practices include meticulous preoperative planning and careful patient positioning to minimize errors.

• High BMI and female sex are risk factors for screw deviation due to bone quality issues.

• Modern systems use sharp burrs to reduce skiving by ensuring smooth entry points.

• Soft tissue management is crucial to prevent interference errors during surgery.

• Intraoperative imaging helps confirm accurate screw placement, reducing registration errors.

• Screw failure rates: Registration errors (60%), skiving errors (26.8%), interference errors (19.5%).

• Newer robotic systems show improved accuracy but still face challenges with registration errors.

• Study limitations include varied resources, surgeon experience, and subjective error reporting.

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Prone Lateral Transpsoas Approach to the Spine: A Technical Guide for Mastery

Int J Spine Surg 2025, 19 (S1) S19-S27

• The prone lateral transpsoas (PTP) approach offers an alternative to traditional lateral lumbar interbody fusion (LLIF), allowing direct posterior access without repositioning the patient.

• Advantages of PTP include improved segmental lordosis, single-position surgery, and ease of posterior techniques, though it has a distinct learning curve.

• The technical guide aims to shorten the learning curve, optimize surgical workflow, and ensure patient safety through preoperative planning and technical adjustments.

• Preoperative imaging is crucial for assessing anatomical characteristics and guiding surgical approach decisions.

• Patient positioning in PTP involves prone positioning on a radiolucent table, with special attention to stabilizing the pelvis and optimizing working angles.

• Intraoperative monitoring with triggered electromyography (t-EMG) is essential to minimize lumbar plexus injury risk.

• Technical pearls include strategies for retractor positioning, minimizing retraction time, and using intraoperative navigation to enhance safety and efficiency.

• Conclusion: PTP LIF is a viable alternative to traditional methods, offering significant benefits but requiring mastery of its unique technical nuances.

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Lateral Transpsoas Interbody Fusion

International Journal of Spine Surgery, Vol. 19, No. S1, 2025, pp. S7–S18

• The lateral transpsoas approach to lumbar interbody fusion is widely adopted for various indications, offering benefits like disc height restoration and alignment correction, despite its risks such as bowel and vascular injury.

• XLIF (Extreme Lateral Interbody Fusion) is a minimally invasive technique introduced in 2006, primarily for degenerative disc disease, and has since expanded for other spinal conditions.

• The approach’s benefits include preserving the anterior and posterior longitudinal ligaments and creating a stable mechanical environment for alignment correction.

• Risks and complications include potential nerve injuries with variable incidences, anterior thigh pain, and vascular injuries, especially at L4-L5 levels due to anatomical constraints.

• Preoperative imaging and patient positioning are crucial for safety, involving detailed assessments of neurovascular structures and careful positioning to minimize risks.

• Intraoperative neuromonitoring is essential for protecting the lumbar plexus, with multimodal approaches recommended for enhanced safety.

• Outcomes of the approach have shown reliable fusion rates and significant improvements in pain and function, making it a valuable tool in spine surgery.

• Training and technique precision are critical for minimizing complications and maximizing the benefits of this minimally invasive approach.

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Is multilevel MIS-TLIF with bilateral facetectomy a lordosing procedure?

J Neurosurg Spine 42:158–168, 2025

• Objective: The study aimed to evaluate the outcomes of 3-level minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and its effect on sagittal balance, particularly in patients with different preoperative segmental lordosis (SL) values.

• Methods: A retrospective analysis of 47 patients who underwent 3-level MIS-TLIF was conducted, with a focus on radiological and clinical outcomes.

• Surgical Techniques: The procedure involved using bullet-shaped static polyetheretherketone cages filled with autologous bone graft and demineralized bone matrix (DBM).

• Results: Patients with a preoperative SL ≤ 27° showed significant improvements in spinopelvic parameters, while those with SL > 27° had insignificant changes.

• Clinical Outcomes: All patients reported clinical improvements, as evidenced by the Oswestry Disability Index and visual analog scale scores.

• Conclusions: The study concluded that 3-level MIS-TLIF can effectively improve sagittal balance, especially in patients with a smaller preoperative lordotic curve.

• Implications: The findings suggest that MIS-TLIF is beneficial for restoring lumbar alignment and improving clinical outcomes in specific patient groups.

• Limitations: The study’s limitations include a small sample size and lack of a control group, which may affect the generalizability of the results.

 

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Improved clinical and radiographic outcomes with expandable cages in transforaminal lumbar interbody fusion

J Neurosurg Spine 42:147–157, 2025

• Expandable cages improve clinical and radiographic outcomes in TLIF compared to static cages.

• Patients with expandable cages experienced greater increases in segmental lumbar lordosis (SL).

• Expandable cages resulted in fewer readmissions and less adjacent-segment disease (ASD).

• Lower estimated blood loss (EBL) with expandable cages, but similar operative times.

• No significant differences in intraoperative or perioperative complications between cage types.

• Patients with expandable cages were more likely to be symptom-free at last follow-up.

• Expandable cages showed persistent improvements in radiographic parameters over time.

• Propensity score matching used to create comparable cohorts for analysis.
• Study focused on one or two-level open TLIF procedures to reduce heterogeneity.

• Expandable cages allow for better restoration of SL without the need for complex surgeries.

• Study limitations include absence of randomized controlled trials and short follow-up durations.

• Findings may not apply to minimally invasive TLIFs or multilevel surgeries.

• Data collected retrospectively from Brigham and Women’s Hospital from 2016 to 2023.

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Surgical Strategy for Dumbbell-Shaped Cervical Schwannoma at the Vicinity of the Vertebral Artery

Operative Neurosurgery 28:165–174, 2025

• Objective: The study proposes a surgical strategy for preserving the vertebral artery (VA) during the excision of dumbbell-shaped cervical schwannomas using anatomic layers, specifically the perineurium.

• Methods: A retrospective analysis was conducted on 37 patients who underwent surgery for cervical schwannomas from January 2004 to July 2023.

• Results: The perineurium acted as a protective barrier during surgery, preventing VA injury in most cases. Gross total resection was achieved in 67.6% of patients.

• Complications: VA injury occurred in one patient, but no new neurological deficits were reported post-surgery.

• Subperineurial Dissection: This technique is crucial for safeguarding adjacent structures and preventing VA injury.

• Residual Tumor Management: Residual tumors were observed in some cases, with regrowth occurring near the neural foramen requiring secondary surgery.

• Conclusion: Subperineurium dissection is a vital strategy in preventing VA injury during schwannoma resection.

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Hook Fixation at Uppermost Instrumented Vertebra +1 Reduced Proximal Junctional Failure in Adult Patients With Spinal Deformity Having Achieved Optimal Deformity Correction by Sagittal Age-Adjusted Score

Neurosurgery 96:308–317, 2025

• Study Focus: The study investigates risk factors for proximal junctional failure (PJF) in elderly patients undergoing spinal deformity surgery despite achieving optimal sagittal correction.

• Methodology: Retrospective analysis of patients aged 60+ who underwent ≥5-level spinal fusion, focusing on those achieving optimal sagittal correction relative to the sagittal age-adjusted score (SAAS).

• Key Findings: High body mass index (BMI), high lumbar distribution index (LDI), and absence of hook fixation at UIV + 1 are significant risk factors for PJF.

• Statistical Analysis: Multivariate analysis confirmed these risk factors, with BMI and LDI showing significant predictive power for PJF development.

• Clinical Implications: Managing BMI, LDI, and ensuring hook fixation at UIV + 1 could reduce PJF rates, even with optimal sagittal correction.

• Limitations: The study’s generalizability is limited by the predominance of patients with UIV in the lower thoracic spine and inconsistent use of preventive methods.

• Conclusion: Proper management of identified risk factors, along with optimal sagittal correction, may further decrease PJF incidence.

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A Novel Marking Technique for Accurate Minimal Invasive Approaches in Spine Tumor Surgeries With Activated Carbon Marking

Operative Neurosurgery 28:255–261, 2025

To describe a novel, practical, reproducible, and effective preoperative marking technique for accurate localization of the spinal level in a series of patients with tumor lesions.

METHODS: We retrospectively analyzed patients undergoing minimally invasive (MIS) surgery for spine tumors from 2016 to 2021, in which this marking technique was used. Twenty-one patients, with tumor lesions involving difficult radioscopic visualization (cervicothoracic junction or upper dorsal spine, C6-T8), were included. Tumor lesion level was previously determined with enhanced MRI in all cases. Twenty-four to forty-eight hours before surgery, computed tomography image–guided carbon marking was performed by administration of aqueous suspension of carbon with a 21-gauge needle placed resembling the MIS approach planned trajectory. During surgery, activated carbon marking was followed until reaching the final target on the bone. Next, sequential dilators and an MIS retractor were placed. Then, bone resection and tumor exeresis were performed according to the case.

RESULTS: Average age was 60.6 years (26-76 years). Fifteen (71%) patients were women. In most cases (76%), tumor pathology involved intradural lesions (meningiomas and schwannomas). In all cases, the marking described allowed to accurately guide the MIS approach to tumor site. Neither intraoperative fluoroscopy nor approach enlargement was required in any procedure. Postoperative complications were reported in only 4 patients, none related with the marking.

CONCLUSION: Computed tomography image–guided activated carbon marking allows to accurately lead MIS approaches in a practical, reproducible, and effective way in cases of tumors localized in regions of the spine of difficult radioscopic visualization.

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Outpatient lateral lumbar interbody fusion: single-institution consecutive case series

J Neurosurg Spine 42:140–146, 2025

Outpatient spine surgery could reduce hospital costs and improve patient outcomes. Outpatient lateral lumbar interbody fusion (LLIF) can be performed for select patients. This study identified and compared the demographic, clinical, and surgical characteristics of patients who underwent outpatient versus inpatient single-level LLIF.

METHODS A retrospective review was conducted of a prospectively collected database of patients who underwent first-time single-level LLIF at a single institution performed by the same surgeon from January 1, 2017, through December 31, 2022. Demographic characteristics, including age, sex, BMI, and medical comorbidities, were collected. Surgical factors, such as level of surgery, operative duration, and estimated blood loss, were also collected. Length of stay and 30-day readmission were the primary outcomes of interest. Patients discharged on the day of surgery or the following day were considered to be in the outpatient group. ANOVA and chi-square tests were performed to compare continuous and categorical variables, respectively. Univariate logistic regression was used to examine the correlation between baseline demographic and surgical variables and outpatient surgery. If a variable significantly correlated with outpatient surgery on univariate analysis, it was subsequently used in multivariate logistic regression.

RESULTS A total of 107 patients underwent first-time single-level LLIF, and 48 (44.9%) did not have posterior instrumentation. Fifty-three (49.5%) patients were women. The median age and BMI were 66.3 years and 28.9, respectively. The mean length of stay was 1 day (range 0–4 days), with 71 (66.4%) of 107 single-level LLIFs managed on an outpatient basis. There were no readmissions within 30 days. Patients in the outpatient group were more likely than patients in the inpatient group to be male (59% [42/71] vs 25% [9/36], p = 0.002), have a low LACE (risk criteria based on length of stay, acuity of the admission, comorbidity of the patient, and emergency department use within 6 months before admission) readmission index (63% [45/71] vs 28% [10/36], p < 0.001), and have a stand-alone construct (62% [44/71] vs 11% [4/36], p < 0.001). The outpatient cohort also had a shorter mean operative duration (104.4 vs 175.5 minutes, p < 0.001) and lower mean estimated blood loss (20 vs 100 mL, p < 0.001). There was no difference in age between the groups. Factors that remained significant on multivariate logistic regression were male sex (OR 0.14, 95% CI 0.04–0.53; p = 0.004), lower LACE readmission index (OR 0.06, 95% CI 0.02–0.25; p < 0.001), and stand-alone construct (OR 8.17, 95% CI 1.49–44.74; p = 0.02).

CONCLUSIONS Multiple baseline and surgical characteristics were more common in the outpatient setting. With appropriate patient selection, single-level LLIF can be achieved on an outpatient basis.

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Does Baseline Facet Arthropathy Influence Early Clinical and Radiographic Outcomes After Cervical Disc Replacement?

Neurosurgery 96:87–95, 2025

Severe facet arthropathy is generally a contraindication to undergoing cervical disc replacement (CDR) due to associated instability and potentially limited improvement in neck pain caused by arthropathy. This study evaluates the influence of facet arthropathy on radiographic/early clinical outcomes after CDR.

METHODS: One/two-level CDR patients from a single surgeon’s prospectively maintained database created 2 cohorts based on facet arthropathy: grade 0-1 or 2-3 (milder/moderate arthropathy). Patient-reported outcome measures for neck disability, neck/arm pain, depressive burden, mental/physical health/function were obtained preoperatively and through final follow-up (average follow-up: 8.5 ± 6.5 months). Preoperative/postoperative radiographs measured segmental lordosis and C2-C7/segmental range of motion (ROM) and determined facet grade for each operative level. Demographic differences, perioperative variables, baseline patient-reported outcomes, and intercohort differences/ changes for postoperative patient-reported/radiographic outcomes were determined.

RESULTS: Of 161 patients, 100 were in the milder arthropathy group. There were no differences in baseline patientreported outcomes. Patients with moderate arthropathy reported superior 6-week 12-Item Veterans Rand Mental/ Physical Composite Scores (P ≤ .047, all). By final follow-up, moderate patients reported better 12-Item Veterans Rand Mental/Physical Composite Scores/Patient-Reported Outcome Measurement Information System-Physical Function/Patient-Health Questionnaire-9 (P ≤ .049, all). Cohorts reported similar improvements in all patientreported outcomes by 6 weeks/final follow-up. Those with more severe facet arthropathy had significantly shorter preoperative disc heights (P < .001). Accounting for baseline disc height differences, by final follow-up, moderate patients had lower segmental ROM (P = .036). There were no significant differences in radiographic measurement changes (P ≥ .264, all).

CONCLUSION: Postoperatively, patients with moderate facet arthropathy reported lower depressive burden, better mental health/physical function, and lower segmental ROM. However, this did not translate to inferior short-term clinical outcomes. Further study should be conducted on the relationship between clinical/radiographic outcomes in CDR patients with facet arthropathy.

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Outcome prediction following lumbar disc surgery: a longitudinal study of outcome trajectories, prognostic factors, and risk models

J Neurosurg Spine 42:33–42, 2025

This study aimed to 1) describe the 2-year postoperative trajectories of leg pain and overall clinical outcome after surgery for radiculopathy, 2) identify the preoperative prognostic factors that predict trajectories representing poor clinical outcomes, and 3) develop and internally validate multivariable prognostic models to assist with clinical decision-making.

METHODS This retrospective cohort study included patients enrolled in the Canadian Spine Outcomes and Research Network who were diagnosed with lumbar disc pathology and radiculopathy and had undergone lumbar discectomy at one of 18 spine centers. Potential outcome predictors included preoperative demographic, health-related, and clinical prognostic factors. Clinical outcomes were 1) 2-year univariable latent trajectories of leg pain intensity (numeric pain rating scale) and 2) overall outcomes comprising multivariable trajectories showing the combined postoperative courses of leg and back pain intensity (numeric pain rating scale) together with pain-related disability (Oswestry Disability Index). Each outcome model identified a subgroup of patients classified as experiencing a poor outcome based on minimal change in their clinical status after surgery. Multivariable risk model performance and internal validity were evaluated with discrimination and calibration statistics based on bootstrap shrinkage with 500 resamplings.

RESULTS The authors included data from 1142 patients (47.6% female). The trajectory models identified 3 subgroups based on the patients’ postoperative courses of pain or disability: 88.6% of patients in the leg pain model and 71.9% in the overall outcome model experienced a good-to-excellent outcome. The models classified 11.4% (leg pain outcome) and 28.2% (overall outcome) of patients as experiencing a poor clinical outcome, which was defined as minimal improvement in pain or disability after surgery. Eleven individual demographic, health, and clinical factors predicted patients’ poor leg pain and overall outcomes. The performance of the multivariable risk model for leg pain was inadequate, while the overall outcome model had acceptable discrimination, calibration, and internal validity for predicting a poor surgical outcome.

CONCLUSIONS Patients with lumbar radiculopathy experience heterogeneous postoperative trajectories of pain and disability after lumbar discectomy. Individual preoperative factors are associated with postoperative outcomes and can be combined within a multivariable risk model to predict overall patient outcome. These results may inform clinical practice but require external validation before confident clinical implementation.

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Patients May Return to Work Sooner After Laminoplasty: Occupational Outcomes of the Cervical Spondylotic Myelopathy Surgical Trial

Neurosurgery 96:131–141, 2025

Return-to-work (RTW) is an important outcome for employed patients considering surgery for cervical spondylotic myelopathy (CSM). We conducted a post hoc analysis of patients as-treated in the Cervical Spondylotic Myelopathy Surgical Trial, a prospective, randomized trial comparing surgical approaches for CSM to evaluate factors associated with RTW.

METHODS: In the trial, patients were randomized (2:3) to either anterior surgery (anterior cervical decompression/fusion [ACDF]) or posterior surgery (laminoplasty [LP], or posterior cervical decompression/fusion [PCDF], at surgeon’s discretion). Work status was recorded at 1, 3, 6, and 12 months postoperatively. For patients working full-time or part-time on enrollment, time to RTW was compared across as-treated surgical groups using discrete-time survival analysis. Multivariate logistic regression was used to assess predictors of RTW. Clinical outcomes were compared using a linear mixed-effects model. RESULTS: A total of 68 (42%) of 163 patients were working preoperatively and were analyzed. In total, 27 patients underwent ACDF, 29 underwent PCDF, and 12 underwent LP. 45 (66%) of 68 patients returned to work by 12 months. Median time to RTW differed by surgical approach (LP = 1 month, ACDF = 3 months, PCDF = 6 months; P = .02). Patients with longer length-of-stay were less likely to be working at 1 month (odds ratio 0.51; 95% CI, 0.29-0.91; P = .022) and 3 months (odds ratio 0.39; 95% CI, 0.16-0.96; P = .04). At 3 months, PCDF was associated with lower Short-Form 36 physical component summary scores than ACDF (estimated mean difference [EMD]: 6.42; 95% CI, 1.4-11.4; P = .007) and LP (EMD: 7.98; 95% CI, 2.7-13.3; P = .003), and higher Neck Disability Index scores than ACDF (EMD: 12.48; 95% CI, 2.3-22.7; P = .01) and LP (EMD: 15.22; 95% CI, 2.3-28.1; P = .014), indicating worse perceived physical functioning and greater disability, respectively.

CONCLUSION: Most employed patients returned to work within 1 year. LP patients resumed employment earliest, while PCDF patients returned to work latest, with greater disability at follow-up, suggesting that choice of surgical intervention may influence occupational outcomes.

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Could indirect decompression occur for cord compression by the ligamentum flavum with anterior cervical discectomy and fusion?

J Neurosurg Spine 42:100–109, 2025

Cord compression by the ligamentum flavum (CCLF) has been reported to adversely affect the clinical outcomes of anterior cervical discectomy and fusion (ACDF). While indirect decompression does occur for foraminal stenosis with ACDF, whether ACDF could improve CCLF with the distraction of disc space remains unclear. This study aimed to identify 1) whether indirect decompression occurs for CCLF with ACDF, and 2) risk factors that hinder the improvement of CCLF.

METHODS This retrospective cohort study included 119 patients who underwent ACDF for the treatment of cervical myelopathy and CCLF was detected on preoperative MRI. Patients who demonstrated improvement in CCLF grade after ACDF were included in the improved group, while those who did not show improvement were classified as the unimproved group. Patient characteristics, cervical sagittal parameters, neck and arm pain visual analog scale score, and Japanese Orthopaedic Association (JOA) score were assessed. A comparison between the improved and unimproved groups was performed. Regression analyses were performed to identify factors associated with CCLF grade improvement.

RESULTS Overall, 58.0% (69/119) of patients showed improvement in CCLF grade after ACDF. CCLF grade did not improve in the remaining 42.0% (50/119) of patients, and 3.4% (4/119) of patients experienced aggravation of CCLF after ACDF. Preoperative spondylolisthesis (OR 0.252, 95% CI 0.090–0.711; p = 0.009) and greater segmental lordosis 3 months postoperatively (OR 0.835, 95% CI 0.731–0.953; p = 0.008) were the factors that hindered the improvement of CCLF after ACDF. Furthermore, patients with higher pre- or postoperative CCLF grades showed significantly less improvement in JOA score 2 years postoperatively.

CONCLUSIONS Indirect decompression for CCLF with ACDF is not reliable because 42.0% of patients did not demonstrate improvement in CCLF grade after the operation. Preoperative spondylolisthesis and postoperative increased segmental lordosis were risk factors for failure of CCLF improvement. Both pre- and postoperative higher CCLF grades were associated with poor neurological recovery 2 years postoperatively.

 

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Use of Patient-Specific Interbody Cages Through a Minimally Invasive Lateral Approach for Unstable Lumbar Spondylodiskitis

Operative Neurosurgery 28:59–68, 2025

Patients with diskitis/osteomyelitis who do not respond to medical treatment or develop spinal instability/deformity may warrant surgical intervention. Irregular bony destruction due to the infection can pose a challenge for spinal reconstruction. The authors report a lateral approach using patient-specific interbody cages combined with posterior or lateral instrumentation to achieve spinal reconstruction for spinal instability/deformity from spondylodiskitis.

METHODS: This is a retrospective review of 4 cases undergoing debridement, lateral lumbar interbody fusion using patient-specific interbody cages, and supplemental lateral or posterior instrumentation for spinal instability/deformity after spondylodiskitis. The surgical technique is reported, as are the clinical and imaging outcomes.

RESULTS: Four male patients with a mean age of 69 years comprised this study. One had lateral lumbar interbody fusion at L2/3 and 3 at L4/5. The mean hospital stay was 5.8 days. The mean follow-up was 8.5 months (range 6-12 months). There were no approach-related neurological injuries or complications. The mean visual analog scale back pain scores improved from 9.5 to 1.5, and the mean Oswestry disability index improved from 68.5 to 23 at the end of the follow-up. The mean lumbar lordosis increased from 18°to 51°. The segmental angle increased from 6.5°to 18°. The coronal shift was 2.8 cm preoperatively and 0.9 cm postoperatively. The coronal Cobb angle reduced from 8.8°preoperatively to 2.8°postoperatively. On postoperative computed tomography, all patients had interval development of bridging bone across the surgical level through or around the cage. None of them developed cage migration or subsidence.

CONCLUSION: Patients with irregular bony destruction due to diskitis/osteomyelitis may benefit from patient-specific cages for spinal reconstruction to address spinal instability and deformity.

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Endoscopic Versus Traditional Thoracic Discectomy: A Multicenter Retrospective Case Series and Meta-Analysis

Neurosurgery 96:152–171, 2025

Surgical treatment for symptomatic thoracic disc herniations (TDH) involves invasive open surgical approaches with relatively high complication rates and prolonged hospital stays. Although advantages of full endoscopic spine surgery (FESS) are well-established in lumbar disc herniations, data are limited for the endoscopic treatment of TDH despite potential benefits regarding surgical invasiveness. The aim of this study was to provide a comprehensive evaluation of potential benefits of FESS for the treatment of TDH.

METHODS: PubMed, MEDLINE, EMBASE, and Scopus were systematically searched for the term “thoracic disc herniation” up to March 2023 and study quality appraised with a subsequent meta-analysis. Primary outcomes were perioperative complications, need for instrumentation, and reoperations. Simultaneously, we performed a multicenter retrospective evaluation of outcomes in patients undergoing full endoscopic thoracic discectomy.

RESULTS: We identified 3190 patients from 108 studies for the traditional thoracic discectomy meta-analysis. Pooled incidence rates of complications were 25% (95% CI 0.22-0.29) for perioperative complications and 7% (95% CI 0.05-0.09) for reoperation. In this cohort, 37% (95% CI 0.26-0.49) of patients underwent instrumentation. The pooled mean for estimated blood loss for traditional approaches was 570 mL (95% CI 477.3-664.1) and 7.0 days (95% CI 5.91-8.14) for length of stay. For FESS, 41 patients from multiple institutions were retrospectively reviewed, perioperative complications were reported in 4 patients (9.7%), 4 (9.7%) required revision surgery, and 6 (14.6%) required instrumentation. Median blood loss was 5 mL (IQR 5-10), and length of stay was 0.43 days (IQR 0-1.23).

CONCLUSION: The results suggest that full endoscopic thoracic discectomy is a safe and effective treatment option for patients with symptomatic TDH. When compared with open surgical approaches, FESS dramatically diminishes invasiveness, the rate of complications, and need for prolonged hospitalizations. Full endoscopic spine surgery has the capacity to alter the standard of care for TDH treatment toward an elective outpatient surgery.

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Diffusion MRI Metrics Characterize Postoperative Clinical Outcomes After Surgery for Cervical Spondylotic Myelopathy

Neurosurgery 96:69–77, 2025

Advanced diffusion-weighted MRI (DWI) modeling, such as diffusion tensor imaging (DTI) and diffusion basis spectrum imaging (DBSI), may help guide rehabilitation strategies after surgical decompression for cervical spondylotic myelopathy (CSM). Currently, however, postoperative DWI is difficult to interpret, owing to signal distortions from spinal instrumentation. Therefore, we examined the relationship between postoperative DTI/DBSIextracted from the rostral C3 spinal level—and clinical outcome measures at 2-year follow-up after decompressive surgery for CSM.

METHODS: Fifty patients with CSM underwent complete clinical and DWI evaluation—followed by DTI/DBSI analysis—at baseline and 2-year follow-up. Clinical outcomes included the modified Japanese Orthopedic Association score and comprehensive patient-reported outcomes. DTI metrics included apparent diffusion coefficient, fractional anisotropy, axial diffusivity, and radial diffusivity. DBSI metrics evaluated white matter tracts through fractional anisotropy, fiber fraction, axial diffusivity, and radial diffusivity as well as extra-axonal pathology through restricted and nonrestricted fraction. Cross-sectional Spearman’s correlations were used to compare postoperative DTI/DBSI metrics with clinical outcomes.

RESULTS: Twenty-seven patients with CSM, including 15, 7, and 5 with mild, moderate, and severe disease, respectively, possessed complete baseline and postoperative DWI scans. At 2-year follow-up, there were 10 significant correlations among postoperative DBSI metrics and postoperative clinical outcomes compared with 3 among postoperative DTI metrics. Of the 13 significant correlations, 7 involved the neck disability index (NDI). The strongest relationships were between DBSI axial diffusivity and NDI (r = 0.60, P < .001), DBSI fiber fraction and NDI (r s = À0.58, P < .001), and DBSI restricted fraction and NDI (r s = 0.56, P < .001). The weakest correlation was between DTI apparent diffusion coefficient and NDI (r = 0.35, P = .02).

CONCLUSION: Quantitative measures of spinal cord microstructure after surgery correlate with postoperative neurofunctional status, quality of life, and pain/disability at 2 years after decompressive surgery for CSM. In particular, DBSI metrics may serve as meaningful biomarkers for postoperative disease severity for patients with CSM.

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Are the Umbilicus and Iliac Crests Truly at the Level of L4 to L5? A Computed Tomography-Based Study of Surface Anatomy of the Anterior Lumbar Spine

International Journal of Spine Surgery, Vol. 18, No. 6, 2024, pp. 660–666

This study aimed to determine whether the iliac crests are truly at the level of L4 to L5, accounting for patient demographic and anthropometric characteristics.

Methods: We measured the umbilicus and iliac crests relative to the lumbar spine using computed tomography of patients without spinal pathology, accounting for the influences of patient height, weight, body mass index (BMI), sex, race, and ethnicity.

Results: A total of 834 patients (391 men and 443 women) were reviewed. The location of the umbilicus relative to the lumbar spine demonstrated a unimodal distribution pattern clustered at L4, while the iliac crests were most frequently located from L4 to L5. Iliac crests were located above the L4 to L5 disc space 26.5% of the time. Iliac crests were located at the L4 to L5 disc space 29.8% of the time. No correlations were observed between the umbilicus and iliac crests with patient height, weight, or BMI. There was no difference in the location of the umbilicus with respect to patient sex, race, and ethnicity. The locations of the iliac crests were cephalad in women compared with men and in Hispanics compared with African American, Caucasian, and Asian patients.

Conclusions: The iliac crests were located above the level of the L4 to L5 disc space approximately 26% of the time. The umbilicus is most frequently at the level of the L4 vertebral body. Patient height, weight, and BMI do not influence the location of the umbilicus or the iliac crests relative to the lumbar spine. Patient sex and ethnicity influence the location of the iliac crests but not the umbilicus relative to the lumbar spine.

Clinical Relevance: Modern neurosurgical techniques require clearance of the iliac crests during anterior and anterolateral approaches. Understanding the level of the iliac crests is crucial in planning for transpsoas fusion approaches.

Level of Evidence: 2

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Can pelvic incidence affect changes in sagittal spino‑pelvic parameters between standing and sitting positions in individuals with lumbar degenerative disease?

European Spine Journal (2024) 33:4598–4604

The aim of this study was to explore the correlation between PI and standing-to-sitting changes of the sagittal alignment in patients with lumbar degenerative diseases, and investigate the differences in posture changes among Roussouly types.

Methods A total of 209 patients with lumbar degenerative disease were retrospectively included in this study. All the patients received lateral full body imaging in both standing and sitting positions. Sagittal parameters including SVA, OD-HA, PT, PI, PT/PI, SS, LL, TK, Upper LL (L1-L4) and Lower LL (L4-S1) were measured in both standing and sitting position, and the parameters were compared between two positions. The correlations between PI and lumbo-pelvic changes were analyzed. The postural changes were compared among different Roussouly types.

Results From standing to sitting, all the parameters except PI significantly changed, including SVA, OD-HA, PT, PT/PI, SS, LL, TK, Upper LL and Lower LL. The contribution of lower LL was greater to global LL than upper LL. PI had a significant correlation with ΔPT, ΔSS, ΔLL, ΔUpper LL and ΔLower LL. From standing to sitting, type 4 patients had the most pronounced ΔPT, ΔSS and ΔLL, and ΔLower LL of types 3 and 4 were greater than that of types 1 and 2.

Conclusions In patients with degenerative disease, PI plays an important role in determining the extent of lumbo-pelvic changes from standing to sitting. Among different Roussouly types, type 4 patients have the most pronounced changes of PT, SS and LL, suggesting the relatively greater flexibility of pelvis and lumbar spine.

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Robotic‑assisted single‑position lateral for multilevel circumferential lumbar interbody fusion

Acta Neurochirurgica (2023) 165:3963–3967

Lateral lumbar interbody fusion supplemented with insertion of pedicle screws is a surgical procedure that has gained popularity in the last years, becoming an important tool in the armamentarium of spine surgeons. In recent years, there is a trend to complete both procedures in a single position, thus avoiding flipping the patient prone to insert the pedicle screws. Methods

We describe a step-by-step workflow of the robotic-assisted technique for multilevel lateral lumbar interbody fusion supplemented with posterior instrumentation. The surgical procedure is performed in a single lateral position. For access to L4–5 or L5–S1, an oblique abdominal incision is performed in the same position, and the desired disc space is approached through an oblique or anterior corridor in the retroperitoneal space.

Conclusion Robotic-assisted single-position lateral for multilevel circumferential lumbar interbody fusion is a safe and effective procedure in patients where lumbar stabilization is required. This technique provides patients with a faster recovery and low risk of complications.

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