Study design:

Multicenter cohort.

Objective:

To compare the robot time/screw, radiation exposure, robot abandonment, screw accuracy, and 90-day outcomes between robot-assisted percutaneous and robot-assisted open approach for short lumbar fusion (1-and 2-level).

Summary of background data:

There is conflicting literature on the superiority of robot-assisted minimally invasive spine surgery to open techniques. A large, multicenter study is needed to further elucidate the outcomes and complications between these two approaches.

Methods:

We included adult patients (≥18 years old) who underwent robot-assisted short lumbar fusion surgery from 2015-2019 at four independent institutions. A propensity score matching (PSM) algorithm was employed to control for the potential selection bias between percutaneous and open surgery. The minimum follow-up was 90 days after the index surgery.

Results:

After PSM, 310 patients remained. The mean (standard deviation) charlson comorbidity index was 1.6 (1.5) and 53% of patients were female. The most common diagnoses included high grade spondylolisthesis (grade >2)(48%), degenerative disc disease (22%), and spinal stenosis (25%), and the mean number of instrumented levels was 1.5(0.5). The operative time was longer in the open (198 minutes) vs. the percutaneous group (167 minutes, P-value=0.007). However, the robot time/screw was similar between cohorts (P-value>0.05). The fluoroscopy time/screw for percutaneous (14.4 seconds) was longer than the open group (10.1 seconds, P-value=0.021). The rates for screw exchange and robot abandonment, were similar between groups (P-value>0.05). The estimated blood loss (open:146 mL vs. percutaneous:61.3 mL, P-value < 0.001) and transfusion rate (open:3.9% vs. percutaneous:0%, P-value=0.013) were greater for the open group. The 90-day complication rate and mean length of stay were not different between cohorts(P-value>0.05).

Conclusion:

Percutaneous robot-assisted spine surgery may increase radiation exposure, but can achieve a shorter operative time and lower risk for intraoperative blood loss for short-lumbar fusion. Percutaneous approaches do not appear to have an advantage for other short-term postoperative outcomes. Future multicenter studies on longer fusion surgeries and the inclusion of patient-reported outcomes are needed.Level of Evidence: 3.