47. ALIF reduction rates in grade 1- and 2- spondylolisthesis are more consistent than TLIF.

BACKGROUND CONTEXT Both the ALIF and TLIF are established surgical approaches for treating Grade 1 or 2 L5-S1 spondylolisthesis. Additionally, each procedure poses different complication profiles. There is a rising debate regarding ALIF vs TLIF regarding multiple outcomes including reduction of spondylolisthesis, thus, we aimed to compare our rates of radiographic reduction. PURPOSE The primary purpose of this study was to compare radiographic reduction rates of Grade 1 and 2 spondylolisthesis between anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) for L5-S1 Grade 1 and 2 spondylolisthesis. STUDY DESIGN/SETTING Retrospective cohort study. METHODS We conducted a retrospective review of isolated L5-S1 TLIF or ALIF surgeries at our tertiary care center from 2012-2022. These cases were reviewed for demographics, follow-up, preoperative parameters, surgical characteristics, postoperative parameters, radiographic outcomes, reduction rates and complications encountered. The inclusion criteria were minimum age of 18 years and a grade 1 or 2 spondylolisthesis at L5-S1 treated with ALIF or TLIF. We excluded patients with previous instrumentation, trauma, infection, and no spondylolisthesis. RESULTS We found 156 patients with isolated L5-S1 ALIF or TLIF without any previous instrumentation, of which 96 had surgery for a grade 1 or 2 spondylolisthesis. Of these patients, 26.0% (n=25) had partial reduction and 74.0% (n=71) had complete reduction their spondylolisthesis. Of those that had partial reduction, 16.0% (n=4) were in the ALIF cohort and 84.0% (n=21) were in the TLIF cohort. Of those with complete reduction, 29.6% (n=36) were in the ALIF cohort and 49.3% (n=35) were in the TLIF cohort (P=0.002). A stepwise logistic regression model demonstrated that using the ALIF technique increased the odds of a complete reduction 5.4 times (p=0.005). CONCLUSIONS Although further research is required, when discussing options with patients regarding surgical approaches for Grade 1 or 2 spondylolisthesis, ALIF demonstrates higher radiographic reduction rates than TLIF at L5-S1. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs. Both the ALIF and TLIF are established surgical approaches for treating Grade 1 or 2 L5-S1 spondylolisthesis. Additionally, each procedure poses different complication profiles. There is a rising debate regarding ALIF vs TLIF regarding multiple outcomes including reduction of spondylolisthesis, thus, we aimed to compare our rates of radiographic reduction. The primary purpose of this study was to compare radiographic reduction rates of Grade 1 and 2 spondylolisthesis between anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) for L5-S1 Grade 1 and 2 spondylolisthesis. Retrospective cohort study. We conducted a retrospective review of isolated L5-S1 TLIF or ALIF surgeries at our tertiary care center from 2012-2022. These cases were reviewed for demographics, follow-up, preoperative parameters, surgical characteristics, postoperative parameters, radiographic outcomes, reduction rates and complications encountered. The inclusion criteria were minimum age of 18 years and a grade 1 or 2 spondylolisthesis at L5-S1 treated with ALIF or TLIF. We excluded patients with previous instrumentation, trauma, infection, and no spondylolisthesis. We found 156 patients with isolated L5-S1 ALIF or TLIF without any previous instrumentation, of which 96 had surgery for a grade 1 or 2 spondylolisthesis. Of these patients, 26.0% (n=25) had partial reduction and 74.0% (n=71) had complete reduction their spondylolisthesis. Of those that had partial reduction, 16.0% (n=4) were in the ALIF cohort and 84.0% (n=21) were in the TLIF cohort. Of those with complete reduction, 29.6% (n=36) were in the ALIF cohort and 49.3% (n=35) were in the TLIF cohort (P=0.002). A stepwise logistic regression model demonstrated that using the ALIF technique increased the odds of a complete reduction 5.4 times (p=0.005). Although further research is required, when discussing options with patients regarding surgical approaches for Grade 1 or 2 spondylolisthesis, ALIF demonstrates higher radiographic reduction rates than TLIF at L5-S1.