Cage migration in multilevel stand-alone lateral lumbar interbody fusion: incidence and clinical correlations

J Neurosurg Spine 44:426–435, 2026

This clinical case series compares the incidence and outcomes of lateral interbody cage migration (LCM) following multilevel stand-alone lateral lumbar interbody fusion (LLIF) versus LLIF with posterior pedicle screw instrumentation in 87 age-matched patients. The retrospective analysis reports similar LCM rates (7% vs 5%), no significant differences in complications, and comparable improvements in Oswestry Disability Index and pain scores at ≥1 year follow-up.

The report details patient selection, radiographic assessment methods, operative characteristics, and risk-factor analysis, emphasizing meticulous selection for multilevel stand-alone LLIF. Authors conclude multilevel stand-alone LLIF can be safe in selected patients but call for prospective studies to validate findings and clarify factors contributing to cage migration.

Lateral Cage Migration (LCM) Incidence: LCM occurred in 7% of multilevel stand-alone LLIF cases and 5% of LLIF cases with posterior instrumentation; this difference was not statistically significant.

Patient Selection Criteria: Optimal candidates for multilevel stand-alone LLIF have neutral sagittal and coronal balance, mild to moderate facet arthropathy, stable grade 1 spondylolisthesis, absence of severe central canal stenosis, normal or mildly reduced bone mineral density, and comorbidities or age that increase surgical risk with posterior fixation.

Clinical Outcomes: Both cohorts (stand-alone and posterior instrumentation) showed significant postoperative improvement in Oswestry Disability Index (ODI) and visual analog scale (VAS) scores, with no significant differences between groups.

Complication Rates: Postoperative complication rates were similar between groups (23% stand-alone vs. 20% posterior instrumentation), and no intraoperative complications were reported in either group.

Biomechanical Considerations: Supplemental posterior instrumentation increases construct stability, but clinical significance in preventing LCM in well-selected patients remains unclear; stand-alone LLIF can be safe with meticulous patient selection.

Role of Lateral Plates: Adding lateral plates to stand-alone LLIF does not significantly improve stability or reduce cage migration/subsidence in multilevel constructs and may increase cost and risk.

Risk Factors for LCM: No significant demographic, radiographic, or procedural risk factors for LCM were identified in this study; all patients with LCM had normal bone density, and meticulous surgical technique and patient selection are emphasized.

Study Limitations: Retrospective design, single institution, and small sample size may limit generalizability; prospective studies are needed for further validation.

Fusion Sequence and Risk Factors for Pseudarthrosis in Multilevel Anterior Cervical Discectomy and Fusion

Neurosurgery 97:1153–1161, 2025

This clinical study evaluates fusion rates, fusion timing, and pseudarthrosis risk factors in 119 patients undergoing 2-level versus 3-level anterior cervical discectomy and fusion (ACDF) with minimum two-year follow-up. Fusion was assessed via angular and linear interspinous motion on dynamic radiographs, with Kaplan-Meier and Cox regression analyses.

Key findings show higher and faster fusion in 2-level ACDF; middle levels fuse earliest while caudal levels have lowest rates. Polyetheretherketone (PEEK) cages and multilevel constructs associate with increased pseudarthrosis risk, highlighting material choice and level-specific biomechanics as critical for surgical planning and future research.

Outcome of unilateral versus standard open midline approach for bilateral decompression in lumbar spinal stenosis: is “over the top” really better?

J Neurosurg Spine 31:236–245, 2019

In this retrospective analysis of a prospective multicenter cohort study, the authors assessed which surgical approach, 1) the unilateral laminotomy with bilateral spinal canal decompression (ULBD; also called “over the top”) or 2) the standard open bilateral decompression (SOBD), achieves better clinical outcomes in the long-term follow-up. The optimal surgical approach (ULBD vs SOBD) to treat lumbar spinal stenosis remains controversial.

METHODS The main outcomes of this study were changes in a spinal stenosis measure (SSM) symptoms score, SSM function score, and quality of life (sum score of the 3-level version of the EQ-5D tool [EQ-5D-3L]) over time. These outcome parameters were measured at baseline and at 12-, 24-, and 36-month follow-ups. To obtain an unbiased result on the effect of ULBD compared to SOBD the authors used matching techniques relying on propensity scores. The latter were calculated based on a logistic regression model including relevant confounders. Additional outcomes of interest were raw changes in main outcomes and in the Roland and Morris Disability Questionnaire from baseline to 12, 24, and 36 months.

RESULTS For this study, 277 patients met the inclusion criteria. One hundred forty-nine patients were treated by ULBD, and 128 were treated by SOBD. After propensity score matching, 128 patients were left in each group. In the matched cohort, the mean (95% CI) estimated differences between ULBD and SOBD for change in SSM symptoms score from baseline to 12 months were -0.04 (-0.25 to 0.17), to 24 months -0.07 (-0.29 to 0.15), and to 36 months -0.04 (-0.28 to 0.21). For change in SSM function score, the estimated differences from baseline to 12 months were 0.06 (-0.08 to 0.21), to 24 months 0.08 (-0.07 to 0.22), and to 36 months 0.01 (-0.16 to 0.17). Differences in changes between groups in EQ-5D-3L sum scores were estimated to be -0.32 (-4.04 to 3.40), -0.89 (-4.76 to 2.98), and -2.71 (-7.16 to 1.74) from baseline to 12, 24, and 36 months, respectively. None of the group differences between ULBD and SOBD were statistically significant.

CONCLUSIONS Both surgical techniques, ULBD and SOBD, may provide effective treatment options for DLSS patients. The authors further determined that the patient outcome results for the technically more challenging ULBD seem not to be superior to those for the SOBD even after 3 years of follow-up.

 

Clinical and radiological results of posterior cervical foraminotomy at two or three levels: a 3-year follow-up

Acta Neurochir (2017) 159:2369–2377

Single-level unilateral posterior cervical foraminotomy is regarded as a safe method. However, the outcomes of posterior cervical foraminotomy performed on two or three levels are uncertain and debated. We aimed to analyze the long-term clinical and radiological outcomes of posterior cervical foraminotomy at two or three levels.

Methods From September 2008 to December 2011, a total of 42 patients who underwent a posterior cervical foraminotomy at two or three levels and were followed for at least 3 years were analyzed with retrospective cohort study. Clinical assessments were performed using the visual analog scale (VAS), neck disability index (NDI) and modified MacNab criteria. Radiological evaluation included the assessment of static and dynamic lateral radiographs to identify instability, postlaminectomy kyphotic deformity, adjacent segmental degeneration (ASD), and focal degeneration.

Results The mean VAS improved from preoperative score 8.5 ± 0.3 to postoperative score 1.8 ± 0.5 significantly. The mean presenting NDI score was 32.9 ± 2.0 and the mean postoperative NDI score was 14.2 ± 1.3. Improvement of radiculopathy was displayed in 39 patients (92.9%). During radiological evaluation, no significant change in disc height related to ASD and focal degeneration was noted. However, we confirmed one patient with radiological instability and one patient with radiological postlaminectomy kyphotic deformity.

Conclusions Posterior cervical foraminotomy at two or three levels is fairly effective for treating patients with cervical radiculopathy, and results in long-lasting pain relief and improved quality of life in nearly all patients. However, further studies of three levels that include more patients are needed.