Risk of Postoperative Complications and Revision Surgery Following Robot-assisted Posterior Lumbar Spinal Fusion.

STUDY DESIGN Retrospective Study. OBJECTIVE This investigation examined matched cohorts of LSF patients undergoing robot-assisted and conventional LSF to compare risk of revision, 30-day readmission, 30-day complications, and post-operative opioid utilization. SUMMARY OF BACKGROUND DATA Patient outcomes and complication rates associated with robot-assisted lumbar spinal fusion (LSF) compared to conventional fusion techniques are incompletely understood. METHODS The PearlDiver Research Program (www.pearldiverinc.com) was used to identify patients undergoing primary LSF between 2011 and 2017. Patients receiving robot-assisted or conventional LSF were matched using key demographic and comorbidity variables. Indication for revision was also studied. Risk of revision, 30-day readmission, 30-day complications, and post-operative opioid utilization at 1 and 6 months was compared between the cohorts using multivariable logistic regression additionally controlling for age, gender, and Charlson Comorbidity Index (CCI). RESULTS The percent of LSFs that were robot-assisted rose by 169% from 2011-2017, increasing linearly each year (p = 0.0007). Matching resulted in 2528 patients in each cohort for analysis. Robot-assisted LSF patients experienced higher risk of revision (aOR=2.35, p=<0.0001), 30-day readmission (aOR=1.39, p = 0.0002), and total 30-day complications (aOR = 1.50, p < 0.0001), specifically respiratory (aOR = 1.56, p = 0.0006), surgical site infection (aOR = 1.56, p=0.0061), and implant-related complications (aOR = 1.74, p = 0.0038). The risk of revision due to infection after robot-assisted LSF was an estimated 4.5 fold higher (aOR = 4.46, 95%CI 1.95-12.04, p = 0.0011). Furthermore, robot-assisted LSF had increased risk of revision due to instrument failure (aOR = 1.64, 95%CI 1.05-2.58, p = 0.0300), and pseudarthrosis (aOR = 2.24, 95%CI = 1.32-3.95, p = 0.0037). A higher percentage of revisions were due to infection in robot-assisted LSF (19.0%) than in conventional LSF (9.2%) (p = 0.0408). CONCLUSION Robotic-assisted posterior lumbar spinal fusion is independently associated with increased risk of revision surgery, infection, instrumentation complications, and post-operative opioid utilization compared to conventional fusion techniques. Further research is needed to investigate long-term post-operative outcomes following robot-assisted LSF. Spine surgeons should be cautious when considering immediate adoption of this emerging surgical technology. LEVEL OF EVIDENCE 3.