140. Complications and revision rates in minimally invasive Mazor robotic-guided vs fluoroscopic-guided spinal fusions: the MIS ReFRESH prospective comparative study

As robotic-guidance and minimally invasive approaches become more prevalent in spine surgery, there is a growing interest in high-level scientific evidence of their clinical value. MIS ReFRESH is the first prospective, multicenter study designed to compare robotic-guidance and fluoroscopic techniques for differences in surgical complications, revision surgery rates and exposure to intraoperative radiation. The MIS ReFRESH study assessed adults undergoing minimally invasive (MIS) lumbar fusions of 1-3 levels. To prospectively assess the impact of Mazor robotic-guidance compared to fluoro-guidance on the rates of surgical complications, revision surgery and intraoperative radiation exposure in MIS short lumbar fusions. Prospective, multicenter, controlled, partially randomized study. Adult patients with degenerative lumbar conditions undergoing minimally invasive fusion of 1-3 levels. Comparison of incidence of surgical complications, revision surgeries and intraoperative fluoroscopy time. Analysis of variables through Cox logistic regression model and a Kaplan Meyer Survival Curve of surgical complications. Data were prospectively collected from adult patients indicated for lumbar fusion surgery, including demographics, comorbidities, surgical complications, revision surgeries and use of intraoperative fluoroscopy (in seconds). A single site randomized patients between arms, while other sites enrolled exclusively to one arm. Primary endpoints were analyzed at 1-year follow-up. A total of 9 sites enrolled 485 patients: 374 in the robot-guided arm (RG), and 111 in the fluoro-guided arm (FG). One site randomized patients, 16 to RG and 11 to FG. 93.2% of patients had >1 year follow-up and were included in the analysis of primary endpoints. There were no differences between the groups with regards to gender, Charlson Comorbidity Index (CCI), Diabetes, Cancer or HIV status. RG patients were significantly heavier, younger and included more smokers. Mean age of RG patients was 59.0 years vs 62.5 for FG (p=0.009) and BMI was 31.2 vs 28.1, respectively (p<0.001). Percentage of smokers was almost double in the RG group (15.2% vs 7.2%, p=.029). Surgical time was similar between groups (skin-to-skin time/#screws) at 24.9 min RG and 22.9 FG (p=0.55). RG cases were significantly more complex as 38.2% were 2-3 levels vs 20.7% in FH (p<0.001). One-level fusions were 61.8% RG vs 79.3% FH (p<0.001). Use of fluoroscopy for the instrumentation phase of the surgery was 16.7 sec in RG vs 77.1 sec FH, resulting in a 60 sec average reduction in fluoro per case in RG. Fluoroscopy time per screw was 3.6 seconds RG vs 17.8 seconds FH leading to an 80% average reduction of fluoro time / screw in RG (p<0.001). Average follow-up was 2.1 years in RG and 2.9 years in FG. Within the first year of follow-up there were 38 (10.2%) surgical complications in RG vs 39 (35.1%) in FG, and 5 (1.3%) revisions in RG vs 4 (3.6%) in FG. When evaluated in a Cox logistic regression model that includes age, gender, BMI, CCI and # screws, the Hazard Ratio (HR) for a complication was 5.2 times higher in FG compared to RG (95% Confidence Interval (CI): 0.118-0.307, p<0.001). Hazard ratio for a revision surgery was 8.8 times higher in FG compared to RG cases (95% CI 0.032-0.399, p<0.001). In a prospective, multicenter, comparative study of MIS lumbar fusions, surgeries performed with Mazor robotic guidance were found to have a 5.2 times lower risk of developing a surgical complication and 8.8 times lower risk for revision surgery compared to fluoro-guidance during the first year of follow-up. Normalized surgical times/instrumentation were similar between the two groups and RG reduced fluoro time per screw by 80%, or approximately a minute per case. Mazor Renaissance Robotics (Approved for this indication)

Complications and Revision Rates in Minimally Invasive Robotic-Guided Versus Fluoroscopic-Guided Spinal Fusions

Study Design. Prospective, multicenter, partially randomized. Objective. Assess rates of complications, revision surgery, and radiation between Mazor robotic-guidance (RG) and fluoro-guidance (FG). Summary of Background Data. Minimally invasive surgery MIS ReFRESH is the first study designed to compare RG and FG techniques in adult minimally invasive surgery (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. Nine sites enrolled 485 patients: 374 (RG arm) and 111 (FG arm). 93.2% of patients had more than 1 year f/u. There were no differences for sex, Charlson Comorbidity Index, diabetes, or tumor. Mean age of RG patients was 59.0 versus 62.5 for FG (P = 0.009) and body mass index (BMI) was 31.2 versus 28.1 (P < 0.001). Percentage of smokers was almost double in the RG (15.2% vs. 7.2%, P = 0.029). Surgical time was similar (skin-toskin time/no. of screws) at 24.9 minutes RG and 22.9 FG (P = 0.550). Fluoroscopy during surgery/no. of screws was 15.5 seconds RG versus 35.4 seconds FG, (15 seconds average reduction). Fluoroscopy time during instrumentation/no. of screws was 3.6 seconds RG versus 17.8 seconds FG showing an 80% average reduction of fluoro time/screw in RG (P< 0.001). Within 1 year follow-up, there were 39 (10.4%) surgical complications RG versus 39 (35.1%) FG, and 8 (2.1%) revisions RG versus 7 (6.3%) FG. Cox regression analysis including age, sex, BMI, CCI, and no. of screws, demonstrated that the hazard ratio (HR) for complication was 5.8 times higher FG versus RG (95% CI: 3.5-9.6, P< 0.001). HR for revision surgery was 11.0 times higher FG versus RG cases (95% CI 2.9-41.2, P< 0.001). Conclusion. 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 1 min/case)

Reduction in complication and revision rates for robotic-guided short-segment lumbar fusion surgery: results of a prospective, multi-center study

Studies evaluating robotic guidance in lumbar fusion are limited primarily to evaluation of screw accuracy and perioperative complications. This is the first study to evaluate granular differences in short and long-term complication and revision rate profiles between robotic (RG) fluoroscopic (FG) guidance for minimally invasive short-segment lumbar fusions. A retrospective analysis of a prospective, multi-center database was performed. Complications were subdivided into surgical (further subcategorized into adjacent segment disease, new-onset back pain, radiculopathy, motor-deficit, hardware failure, pseudoarthrosis), wound, and medical complications. Complication and revision rates were compared between RG and FG groups cumulatively at 30, 90 days, and 1 year. 374 RG and 111 FG procedures were performed. RG was associated with an 86.25, 83.20, and 69.42% cumulative reduction in complication rate at 30, 90 days, and 1 year, respectively, compared to FG (p < 0.001). At all follow-up points, new-onset radiculopathy and medical complications were most prevalent in both groups. The greatest reductions in complication rates were seen for new-onset back pain (88.13%; p = 0.001) and wound complications (95.05%; p < 0.001) at 30 days, new-onset motor deficits (90.11%; p = 0.004) and wound complications (85.16%; p < 0.001) at 90 days, and new-onset motor deficits (85.16%; p = 0.002), wound (85.16%; p < 0.001), and medical complications (75.72%; p < 0.001) at 1 year. RG was associated with a 92.58% (p = 0.002) reduction in revision rate at 90 days and a 66.08% (p = 0.026) reduction at 1 year. RG was associated with significant reductions in postoperative complication rates at all follow-up time points and significant reductions in revision rates at 90 days and 1 year

Fluoroscopy time analysis of a prospective, multi-centre study comparing robotic- and fluoroscopic-guided placement of percutaneous pedicle screw instrumentation for short segment minimally invasive lumbar fusion surgery

Background As minimally invasive spine surgery becomes more widespread, concerns regarding radiation exposure to surgeons and patients alike have become a growing concern. Robotic guidance has been developed as a way to increase the accuracy of instrumentation while decreasing radiation burden. Methods A retrospective analysis of a large, multi-centre, prospective study comparing robotic-guided (RG) to fluoroscopic-guided (FG) (Multi-centre, Partially Randomized, Controlled Trial of MIS Robotic vs. Freehand in Short Adult Degenerative Spinal Fusion Surgeries) was performed to evaluate for differences in radiation exposure between study groups. Results RG was associated with 78.3% (p < 0.001) and 79.8% (p < 0.001) reduction in total and per screw fluoroscopy times, respectively, as compared to FG. RG was also associated with a 50.8% (p < 0.001) reduction in total operative fluoroscopy time. Conclusions RG was associated with significantly lower fluoroscopy times compared to FG. This suggests that utilization of robotic navigation systems may result in decreased operative radiation exposure, which is a growing concern for surgeons performing minimally invasive spine surgery