EP1021 - Analyzing the Amount of Forces Used During Steps of dV5 Low Anterior Colon Resections: Does it Effect Post Operative Outcomes?

Purpose/Background: Force feedback (FFB) on the da Vinci 5 (dV5) platform enables quantitative assessment of surgeon-tissue interaction through objective performance indicators (OPIs). Analysis of these forces can provide insight into how surgical technique, case complexity, and postoperative recovery are interrelated. The force feedback instruments were designed to have the highest accuracy measuring forces between a range of 0.5 N and 6.5 N. This study examined and compared the amount of forces used during each step of robotic low anterior resections (LAR) and their association with patient length of stay, return of bowel function, readmission and complication rates.

Methods/Interventions: A single-surgeon, single-site retrospective cohort analysis was performed on low anterior resections performed on the dV5 system over a 9 month period. Force OPIs from the fenestrated bipolar instrument were generated with operative video, kinematics, and system events. The patients were from stratified using similar complexity, diagnosis, demographics and patient factors. The operation was divided into three key steps: dissection, vessel ligation, and anastomosis. Force metrics included average force, maximum force, and percent time > 6.5 N. Correlations between force metrics and postoperative length of stay (LOS) and return of bowel function (ROBF) were evaluated using Pearson's test; subgroup differences were assessed with two-tailed t-tests and rank-sum analyses. An ML-enabled analytics application using logistic regression predicted phases and steps associated with increased forces, procedural complexity, and outcomes. Predictor variables included patient factors and kinematic OPIs.

Results/Outcomes: A total of 23 cases with complete kinematic data were included. The average amount of force used during all cases was 2.179 N. The maximum force applied ranged from 9.2N to 76.63N with an average of 42.85 N. There was no statistically significant difference between readmission or complications rates and amount of force used. Of the 23 cases, there were no complications and 1 readmission. There was a statistically significant positive correlation between the percent of time spent above 6.5 N and length of stay (LOS) (r = 0.67, p = 0.0005). There was a moderate positive correlation between maximum force and LOS (r = 0.45, p = 0.03) as well as maximum force and return of bowel function (r = 0.42, p = 0.04). Procedure step-level analysis revealed that total mesorectal excision (TME) exhibited one of the highest average forces (2.9 ± 0.83 N). During anastomosis, the distal colon experienced significantly higher forces (3.19 ± 0.91 N) compared with the proximal colon (1.61 ± 0.41 N; p < 0.001). Low anterior resections performed for rectal pathology demonstrated higher average forces during splenic-flexure mobilization (+0.32 N) and distal transection (+0.64 N) when compared with LAR for sigmoid colon pathology. Kinematic analysis showed greater hand-controller workspace volume during splenic-flexure mobilization (p = 0.01) and in complex TME cases (p = 0.04).

Conclusion/Discussion: The correlation analyses demonstrated that greater intraoperative force exposure was associated with longer length of stay and the highest forces were seen during TME dissection. The use of dV5 force feedback provides a way to contextualize objective performance indicators and interpret how intraoperative surgical techniques influence postoperative outcomes.

Force Metric Outcomes
Force Metric Outcomes