Treatment of Grade II Isthmic Spondylolisthesis: Comparison of Minimally Invasive Transforaminal and Anterior Lumbar Interbody Fusion

Presented at SMISS Annual Forum 2016
By Kern Singh MD
With Dustin Massel BS, Benjamin Mayo BA, Ankur Narain BA, Fady Hijji BS, Krishna Kudaravalli BS, Kelly Yom BA,

Disclosures: Kern Singh MD A; CSRS Resident Grant. B; DePuy, Zimmer, Stryker, CSRS, ISASS, AAOS, SRS, Vertebral Column - ISASS. D; Avaz Surgical, LLC, Vital 5, LLC. F; Zimmer, Stryker, Pioneer, Lippincott Williams & Wilkins, Th Dustin Massel BS None, Benjamin Mayo BA A; CSRS Resident Grant., Ankur Narain BA None, Fady Hijji BS None, Krishna Kudaravalli BS None, Kelly Yom BA None,

Introduction

Significant controversy exists regarding the best treatment for isthmic spondylolisthesis (IS). The use of minimally invasive (MIS) procedures for the treatment of grade II IS has not been well characterized in the literature. To our knowledge, no current studies have compared outcomes between minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) for the treatment of grade II IS. 

Aims/Objectives

To compare clinical outcomes between minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) for treatment of grade II isthmic spondylolisthesis (IS). 

Methods

A prospectively maintained surgical database of patients who underwent a primary 1- or 2-level MIS TLIF or ALIF for grade II isthmic spondylolisthesis (IS) between 2007-2015 was reviewed. Patients were classified into the TLIF or ALIF cohort according to the procedure performed. The TLIF cohort underwent a bilateral tubular approach with bilateral interbody cage placement, whereas the ALIFs were performed using an anterior interbody fusion with posterior percutaneous pedicle screw placement. Baseline patient demographics and characteristics were compared between cohorts using Student’s t-test for continuous variables and Chi-square analysis for categorical variables. Peri- and postoperative outcomes were analyzed using Poisson regression with robust error variance (binary outcomes) or linear regression (continuous outcomes) adjusted for age, sex, BMI, operative level, smoking status, insurance, comorbidity burden, and preoperative visual analogue scale. 

Results

A total of 65 patients were included in the analysis. Of these, 46 (70.8%) underwent a TLIF and 19 (29.2%) underwent an ALIF. Patient demographics and preoperative characteristics were similar between cohorts. The TLIF cohort demonstrated shorter operative times (148.3±36.2 vs 183.4±70.5, p=0.026) when compared to the ALIF cohort. There were no significant differences in other peri- or postoperative outcomes between cohorts. 

Conclusions

Patients with grade II IS experience similar clinical outcomes following an MIS TLIF and ALIF. The additional operative time in the ALIF cohort (posterior percutaneous fixation) did not result in a delay in discharge. The ALIF cohort demonstrated a higher, though not statistically significant, arthrodesis rate than the MIS TLIF cohort. This may be due to the better fusion environment provided by the larger graft that can be placed using the anterior approach.