Study design:

Prospective, multi-center, partially randomized.

Objective:

Assess rates of complications, revision surgery, and radiation between Mazor robotic-guidance (RG) and fluoro-guidance (FG).

Summary of background data:

MIS ReFRESH is the first study designed to compare RG and FG techniques in adult MIS lumbar fusions.

Methods:

Primary endpoints were analyzed at 1 year follow-up. Analysis of variables through Cox logistic regression and a Kaplan-Meier Survival Curve of surgical complications.

Results:

9 sites enrolled 485 patients: 374 (RG arm) and 111 (FG arm). 93.2% of patients had >1 year f/u. There were no differences for gender, Charlson Comorbidity Index, diabetes, or tumor. Mean age of RG patients was 59.0 vs. 62.5 for FG (p = 0.009) and BMI was 31.2 vs. 28.1 (p < 0.001). Percentage of smokers was almost double in the RG (15.2% vs. 7.2%, p = .029). Surgical time was similar (skin-to-skin time/#screws) at 24.9 min RG and 22.9 FG (p = 0.550). Fluoroscopy during surgery/#screws was 15.5 sec RG vs. 35.4 sec FG, (15 sec average reduction). Fluoroscopy time during instrumentation/#screws was 3.6 seconds RG vs. 17.8 seconds FG showing an 80% average reduction of fluoro time/screw in RG (p < 0.001). Within one year follow-up, there were 39 (10.4%) surgical complications RG vs. 39 (35.1%) FG, and 8 (2.1%) revisions RG vs. 7 (6.3%) FG. Cox regression analysis including age, gender, BMI, CCI and # screws, demonstrated that the Hazard Ratio (HR) for complication was 5.8 times higher FG vs. RG (95% CI: 3.5-9.6, p < 0.001). HR for revision surgery was 11.0 times higher FG vs. RG cases (95% CI 2.9-41.2, p < 0.001).

Conclusions:

Mazor robotic-guidance was found to have a 5.8 times lower risk of a surgical complication and 11.0 times lower risk for revision surgery. Surgical time was similar between groups and robotic-guidance reduced fluoro time per screw by 80% (approximately one minute/case).Level of Evidence: 2.