507 - Complications and Revision Rates in Robotic-guided vs. Fluoro-guided M...

General Session: MIS - Hall F

Presented by: V. Hsu


S. Schroerlucke(1), M. Wang(2), A. Cannestra(3), C. Good(4), J. Lim(5), V. Hsu(6), F. Zahrawi(7), H. Villalobos(8), P. Ramirez(8), T. Sweeney(9)

(1) St Francis Hospital / Tabor Orthopedics / Crosstown Back and Pain Institute, Orthopaedic Surgery, Memphis, TN, United States
(2) University of Miami Miller School of Medicine, Neurological Surgery, Miami, FL, United States
(3) Baptist Medical Center, Neurological Surgery, Jacksonville, FL, United States
(4) Reston Hospital Cender, Orthopaedic Surgery, Reston, VA, United States
(5) Reston Hospital Center, Orthopaedics, Reston, VA, United States
(6) Abington Hospital, Orthopaedic Surgery, Abington, PA, United States
(7) Florida Hospital, Orthopaedic Surgery, Celebration, FL, United States
(8) Osceola Regional Medical Center, Orthopaedic Surgery, Osceola, FL, United States
(9) Doctors Hospital of Sarasota, Orthopaedic Surgery, Sarasota, FL, United States


Background Context: 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, comparative, multi-center study designed to assess differences in surgical complication and revision rates, and exposure to intra-operative radiation, in adult degenerative conditions, operated in a minimally invasive (MIS) approach in 1-to-3 level fusions.

Purpose: To prospectively assess the impact of robotic-guidance compared to fluoro-guidance on the incidence of clinical complications and revisions and intra-operative fluoroscopy use in MIS short lumbar fusions.

Study Design/Setting: Prospective, multi-center, controlled, partially randomized study.

Patient Sample: Adults suffering from degenerative disease of the lumbar spine indicated for fusion surgery of 1 to 3 levels.

Outcome Measures: Comparison of incidence of revision surgeries and clinical complications (surgical and medical)through a logistic regression model (Cox). Comparison of intra-operative fluoroscopy use.

Methods: Data were prospectively collected from adult patients indicated for fusion surgery, including demographics, complications, need for revision surgery and use of intra-operative fluoroscopy (in seconds). A single site randomized patients between arms, while other sites enrolled exclusively to one arm.

Results: Altogether, 9 sites enrolled 379 cases: 287 in the robot-guided arm (RG), and 92 in the fluoro-guided arm (FG). One site randomized patients, 15 to RG and 11 to FG. Mean age of RG patients was 59.1 years vs. 62.4 for FG (p=0.032) and BMI was 31.4 vs. 28.0, respectively (p< 0.001). Sex distribution was similar at 62.0% females in RG and 57.4% in FG (p=0.468). Charlson Comorbidity Index was 0.5±0.8 in RG vs. 0.3±0.6 in FG (p=0.022). There were 4.8±1.2 pedicle screws per case in RG vs. 4.3±0.9 screws in FG (p< 0.001). In RG 33% of cases were 2-levels and 5% 3-levels, while in FG 16% were 2-level fusions, and 1% were 3-level fusions. Use of fluoroscopy for the instrumentation phase was 3.8±3.9 seconds/screw in RG vs. 16.9±9.2 in FG (p< 0.001). Average follow up was 174 days in RG and 159 in FG. Within the first year of follow up there were 28 (9.7%) complications in RG vs. 35 (38.0%) in FG, and 4 (1.4%) revisions in RG vs. 4 (4.3%) in FG. When evaluated in a Cox logistic regression model that includes age, gender, BMI, Charlson Comorbidity Index and number of executed screws, the Relative Risk (RR) for a complication was 5.3 times higher in FG compared to RG (95% Confidence Interval (CI): 3.0-9.5, p< 0.001). RR for a revision surgery were 7.1 times higher for a fluoro-guided surgery compared to the robot-guided cases (95% CI 1.6-32.6, p=0.012).

Conclusions: We report our findings from a prospective, multi-center, comparative study of MIS lumbar fusions performed with robotic-guidance in 287 patients vs. fluoro-guidance in 92 controls. RR for a complication or a revision surgery was significantly higher in FG during the first year of follow-up compared to RG (5.3-fold and 7.1-fold, respectively). RG reduced fluoroscopy exposure time per case by 78%, or almost a minute, helping offset the patients' exposure during the pre-operative CT scan required for planning the robotic procedure.