29 - Treatment of Grade II and Higher Isthmic Spondylolisthesis: Comparison...

General Session: MIS-4

Presented by: D. Massel( - View Audio/Video Presentation (Members Only)


B. Mayo(1), D. Massel(1), K. Modi(1), W. Long(1), G. Lopez(1), K. Singh(1)

(1) Rush University Medical Center, Orthopaedic Surgery, Chicago, IL, United States


Background information: Significant controversy exists regarding the best treatment for isthmic spondylolisthesis (IS). The use of minimally invasive (MIS) procedures for the treatment of high grade 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 high-grade IS.

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

Methods: A prospectively maintained surgical database of patients who underwent a primary 1- or 2-level MIS TLIF or ALIF for high-grade (grade 2 or above) 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 (Table 1). 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 (Table 2).

Conclusions: Patients with high-grade 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.

Table 1: Baseline characteristics.

Table 2: Outcomes.