A Comparative Analysis of Revision Rates in Surgical Treatments for Lumbar Isthmic Spondylolisthesis

Study Design: Retrospective Cohort Study. Objective: Isthmic spondylolisthesis is frequently encountered in spine surgical practice, though there is a significant variation in surgical management strategies. We sought to evaluate revision rates between patients who underwent anterior-approach lumbar interbody fusion (ALIF) alone, posterolateral fusion (PLF) alone, PLIF/TLIF, and ALIF+PSF. Methods: This retrospective study utilized a large commercial insurance claims database of patients ≤65 years-old. Patients with isthmic spondylolisthesis who underwent single-level instrumented arthrodesis were included, and those who underwent revision surgery, surgery for deformity, multi-level surgery, or surgery for traumatic, infectious, or neoplastic etiologies were excluded, as determined by ICD-10-CM and CPT codes. Patients were assigned to surgical cohorts of ALIF alone, PLF alone, PLIF/TLIF, and ALIF+PSF based on CPT codes. Additional independent variables included age, sex, decompression at index surgery, and region. The primary outcome was revision arthrodesis or decompression, defined using CPT codes. Kaplan-Meier analysis and Cox Proportional Hazards regression were utilized to assess differences in revision occurrence between cohorts. Results: 1014 patients who underwent single-level arthrodesis for isthmic spondylolisthesis were included. The mean age was 48.6 years, with a mean follow-up of 637.6 days. The majority of patients underwent PLIF/TLIF (60.6%, n = 614), followed by ALIF+PSF (18.5%, n = 188), PLF alone (14.4%, n = 146), and ALIF alone (6.5%, n = 66). The 5-year revision-rate was 11.0% for all patients in the Kaplan-Meier analysis. In multivariable analysis adjusting for confounding factors, ALIF-alone demonstrated significantly higher occurrence of revision compared to both ALIF+PSF (HR 5.0, P = 0.0026) and PLIF/TLIF (HR 5.8, P < 0.0001) groups. Similarly, PLF alone demonstrated significantly higher occurrence of revision surgery compared to PLIF/TLIF (HR 2.4, P = 0.0379) while other comparisons were not statistically significant. Conclusions: In this analysis of single-level arthrodesis for isthmic spondylolisthesis, patients who underwent ALIF alone had higher revision rates than those who underwent PLIF/TLIF and ALIF+PSF surgery, and those who underwent PLF alone had higher revision rates than those who underwent PLIF/TLIF. Surgical strategies providing both anterior and posterior column support resulted in lower real-world revision rates.