STUDY DESIGN:Retrospective cohort study. OBJECTIVE:To evaluate the association between iliac fixation and long-term reoperation risk in patients undergoing multilevel lumbosacral fusion for degenerative pathology. SUMMARY OF BACKGROUND DATA:Spinopelvic fixation using iliac screws is commonly employed to improve construct stability in long lumbar fusions involving the sacrum. While biomechanical benefits are well established, clinical evidence regarding long-term reoperation risk and failure mechanisms in degenerative populations remains limited. METHODS:We identified adult patients undergoing primary elective multilevel lumbosacral fusion (>4 levels) between 2009 and 2023 from a large integrated healthcare spine registry by using iliac fixation. Primary outcome was all-cause reoperation. Secondary outcomes included reoperation for adjacent segment disease (ASD), nonunion, and hardware-related complications. We used Multivariable Cox proportional hazards regression models adjusted for patient and surgical factors to evaluate reoperation risk. Time-stratified analyses addressed nonproportional hazards. RESULTS:A total of 1,301 patients were included, including 483 with iliac fixation and 818 without. Mean follow-up was 6.3 years. At 10 years, crude all-cause reoperation incidence was 26.0% with iliac fixation versus 31.1% without. Iliac fixation was associated with reduced long-term all-cause reoperation risk (>1 y) (HR 0.63, 95% CI 0.43-0.92, P=0.018), but not early reoperation risk. Nonunion-related reoperation risk was significantly lower with iliac fixation (HR 0.30, 95% CI 0.13-0.67, P=0.004). No significant differences were observed in ASD-related reoperation risk. CONCLUSIONS:In patients undergoing multilevel lumbosacral fusion for degenerative pathology, iliac fixation was associated with significantly lower long-term reoperation risk, driven primarily by reduced nonunion-related reoperation. These findings support the role of iliac fixation in improving long-term construct durability. LEVEL OF EVIDENCE:III.

Study Design.Retrospective cohort study.Objective.Anterior cervical discectomy and fusions (ACDF) have become a common and effective means of decompression and stabilization of the cervical spine. Anterior instrumentation with plates and screws (ACDF-P) are increasingly utilized to increase rates of union. However, concerns with plate-related risks have led to the evolution of stand-alone ACDF (ACDF-S) constructs in hopes of reducing adjacent segment degeneration from plate prominence though critics have pointed out potential for subsidence, instability, and nonunions. We sought to evaluate reoperation risk following ACDF-S compared with ACDF-P in a multicenter US-based cohort.Summary of Background Data.Adult patients who underwent primary one to two-level ACDF between C3 and C7 for degenerative disc disease were identified using a health care system's spine registry (2009-2022). Three thousand nine hundred fifty-eight ACDF comprised the final study sample, 278 (7.0%) were ACDF-S. Procedures were performed by 59 surgeons at 16 hospitals.Methods.Multivariable Cox proportional-hazards regression was used to evaluate ACDF-S versus ACDF-P and risk of reoperation for any cause with confounder adjustment. Reoperation for adjacent segment disease (ASD) or nonunion were also evaluated. Secondary analysis stratified by one and two-level ACDF procedures.Results.In adjusted analyses, no differences in all-cause reoperation risk [hazard ratio (HR)=0.97, 95% CI=0.58-1.64] or reoperation for ASD (HR=1.11, 95% CI=0.61-1.99) was observed when comparing ACDF-S to ACDF-P. No differences in reoperation risks were also found when restricted to one-level procedures (all-cause: HR=0.92, 95% CI=0.50-1.68; ASD: HR=0.88, 95% CI=0.44-1.78). For two-level procedures, there were 49 ACDF-S and 1,886 ACDF-P. There were too few events observed for regression analysis.Conclusions.In this large, comparative study including a cohort of nearly 4000 patients, differences in reoperation rates for ACDF-S compared with ACDF-P constructs were not observed. This information could be used to better inform surgeons, patients, administrators, and policy makers between the 2 ACDF options.

STUDY DESIGN:Retrospective cohort study. OBJECTIVE:Anterior cervical discectomy and fusions (ACDF) have become a common and effective means of decompression and stabilization of the cervical spine. Anterior instrumentation with plates and screws (ACDF-P) are increasingly utilized to increase rates of union. However, concerns with plate-related risks have led to the evolution of stand-alone ACDF (ACDF-S) constructs in hopes of reducing adjacent segment degeneration from plate prominence though critics have pointed out potential for subsidence, instability, and nonunions. We sought to evaluate reoperation risk following ACDF-S compared with ACDF-P in a multicenter US-based cohort. SUMMARY OF BACKGROUND DATA:Adult patients who underwent primary one to two-level ACDF between C3 and C7 for degenerative disc disease were identified using a health care system's spine registry (2009-2022). Three thousand nine hundred fifty-eight ACDF comprised the final study sample, 278 (7.0%) were ACDF-S. Procedures were performed by 59 surgeons at 16 hospitals. METHODS:Multivariable Cox proportional-hazards regression was used to evaluate ACDF-S versus ACDF-P and risk of reoperation for any cause with confounder adjustment. Reoperation for adjacent segment disease (ASD) or nonunion were also evaluated. Secondary analysis stratified by one and two-level ACDF procedures. RESULTS:In adjusted analyses, no differences in all-cause reoperation risk [hazard ratio (HR)=0.97, 95% CI=0.58-1.64] or reoperation for ASD (HR=1.11, 95% CI=0.61-1.99) was observed when comparing ACDF-S to ACDF-P. No differences in reoperation risks were also found when restricted to one-level procedures (all-cause: HR=0.92, 95% CI=0.50-1.68; ASD: HR=0.88, 95% CI=0.44-1.78). For two-level procedures, there were 49 ACDF-S and 1,886 ACDF-P. There were too few events observed for regression analysis. CONCLUSIONS:In this large, comparative study including a cohort of nearly 4000 patients, differences in reoperation rates for ACDF-S compared with ACDF-P constructs were not observed. This information could be used to better inform surgeons, patients, administrators, and policy makers between the 2 ACDF options.

INTRODUCTION: Anterior lumbar interbody fusion (ALIF) is a versatile and powerful technique for a variety of lumbar degenerative pathologies. Adding posterior supplementary fixation to ALIF (ALIF+PSF) is common and may confer benefits in terms of higher fusion rate but could contribute to adjacent segment disease (ASD) due to additional rigidity. METHODS: Adult patients who underwent primary ALIF for lumbar degenerative pathology between levels L4-S1 over a 12-year period were included. Cases of trauma, cancer, infection, supplemental decompression, noncontiguous fusions, prior lumbar fusions, and other interbody devices were excluded. Primary outcomes included reoperation for nonunion and ASD. Multivariable Cox proportional hazard regression was used to evaluate risks adjusting for patient characteristics. RESULTS: The study consisted of 1377 cases; 307 ALIF alone and 1070 ALIF+PSF. Mean follow-up time was 5.6-years. 5-year crude nonunion incidence was 2.4% for ALIF only and 0.5% for ALIF+PSF; after adjustment for covariates, a lower operative nonunion risk was observed for ALIF+PSF (HR = 0.22, 95% CI = 0.07-0.70). Of patients deemed potentially suitable for ALIF alone, one would need to add PSF in 53-patients to prevent one case of operative nonunion at a 5-year follow-up (number needed to treat). Five-year operative ASD incidence was 4.3% for ALIF only and 6.2% for ALIF+PSF; with adjustments, no difference was observed between the cohorts (HR = 0.96, 95% CI = 0.53-1.74). CONCLUSIONS: While addition of posterior instrumentation in ALIFs is associated with lower risk of operative nonunion compared to ALIF alone, it is rare in both techniques (<5%). Accordingly, surgeons should evaluate added risks associated with addition of PSF, and rather reserve PSF for patients at higher risk for operative nonunion. Rates of operative ASD were not statistically higher with addition of PSF suggesting concern regarding future ASD may be less supported.