Yusuke Nishi, Yasumitsu Hirano, Yasuhiro Ishiyama
BACKGROUND: The da Vinci 5 (DV5) introduces force feedback (FFb) technology to robotic surgery, aiming to enhance safety through haptic sensation. However, its quantitative impact on specific tissue manipulations in rectal cancer surgery remains unclear. This study evaluated the clinical significance of FFb by analyzing force metrics across different instrument roles. METHODS: We retrospectively analyzed 13 consecutive robotic rectal cancer resections performed by a single expert surgeon. Force data were extracted from system logs for the Cadiere Forceps (static retraction) and Fenestrated Bipolar Forceps (dynamic retraction). Comparisons were made between three settings: Off (N = 3), Low (N = 11), and Medium (N = 5). For "Low" and "Medium" settings, cases overlapped as settings were adjusted intraoperatively. Cumulative force usage time was calculated for each setting. Statistical significance was assessed using the Kruskal-Wallis test. RESULTS: A total of 91,000 + seconds for Cadiere and 68,000 + seconds for Fenestrated Bipolar forceps were analyzed. For the Cadiere Forceps (static retraction), the mean force was significantly reduced as FFb sensitivity increased (Off: 3.07 N, Low: 2.58 N, Medium: 2.03 N; P = 0.039). For the Fenestrated Bipolar Forceps (dynamic retraction), while the mean force showed no significant difference, the median maximum (peak) force was significantly suppressed with higher FFb settings (Off: 36.19 N, Low: 18.82 N, Medium: 10.06 N; P = 0.033). No intraoperative complications related to tissue trauma occurred. CONCLUSIONS: FFb technology in the DV5 effectively modulates surgical force based on the functional role of the instrument. It significantly reduces sustained stress during static retraction and serves as a "safety brake" to cap peak forces during dynamic maneuvers, potentially enhancing the safety of robotic rectal surgery.