Inpatient Opioid Usage and Perioperative Outcomes of Robot-assisted Single-level Minimally Invasive Transformational Lumbar Interbody Fusion: A Comparative Cohort Study

Introduction: The purpose of this study is to compare the inpatient opioid use in patients undergoing robot-assisted (RA) versus fluoroscopy-guided (FG) single-level MIS-TLIF.

Methods: We performed a retrospective review of consecutive patients undergoing RA or FG single-level MIS-TLIF by a single surgeon between October 2019-April 2024. All RA surgeries were performed using the Mazor robotic system. Our primary outcome was inpatient opioid usage measured in morphine milliequivalents (MME). Secondary outcomes included screw accuracy, fluoroscopy dosage, operative time, total anesthesia time, anesthesia time per screw, estimated blood loss (EBL), length of stay (LOS), complications, and rate of screw revision. Screw accuracy was graded using the Gertzbein and Robbins scale. Grades A and B were considered acceptable, and C, D, E indicated misplacement. The two cohorts were compared using univariate analysis. Multivariable analysis modeling on total inpatient MME was used to identify predictors. P < 0.05 was considered significant.

Results: 104 patients (51 FG versus 53 RA) were included. Patients in the RA group were older at baseline (p=.009). Opioid use (total and per day MME) was significantly lower in the RA group (p <.001). Screw accuracy was significantly higher in the RA group, with excellent placement (grade A) in 92.8% (p <.001), and acceptable placement (grades A and B) in 100% (p=.004) of screws. Fluoroscopy dosage (p <.001) and EBL (p=0.015) were significantly lower while total anesthesia time (p=0.042) was higher in the RA group. Operative time, LOS, complications, and rate of screw revision were not significantly different between the two groups. On multivariable analysis, RA was independently associated with a significant decrease in total inpatient MME (OR= -0.33, p<.001).

Conclusion : RA single level MIS-TLIF is independently associated with decreased odds of total inpatient MME. Screw accuracy and total anesthesia time were significantly higher in the RA group while fluoroscopy dosage and EBL were lower compared to FG.