Does Intraperitoneal Washout Further Reduce Pain After Low-Pressure vNOTES Hysterectomy?

The evolution of minimally invasive gynecology has transitioned from traditional laparotomy to laparoscopy, and most recently, to vNOTES (Vaginal Natural Orifice Transluminal Endoscopic Surgery). By combining the visual advantages of endoscopy with the scarless approach of vaginal surgery, vNOTES has demonstrated superior outcomes in terms of reduced postoperative pain, shorter hospital stays, and improved cosmetic results compared to traditional total laparoscopic hysterectomy (TLH). Despite these advancements, post-laparoscopic pain syndrome (PLPS) remains a significant clinical challenge. Characterized by deep-seated abdominal pressure and referred shoulder-tip pain, PLPS is primarily attributed to the irritation of the phrenic nerve caused by residual carbon dioxide and the formation of carbonic acid on the peritoneal surface. In the Trendelenburg position required for gynecologic procedures, this gas often becomes trapped in the subdiaphragmatic space, leading to significant distress that can delay discharge even when the surgical site itself is healing well. The physiological impact of the pneumoperitoneum is largely pressure-dependent. The landmark study by Barczyński and Herman (2004) in general surgery established that maintaining a low-pressure pneumoperitoneum (\<10 mmHg) significantly reduces peritoneal stretching and the subsequent inflammatory response. Furthermore, the technique of intraperitoneal saline washout has been proposed to physically remove residual CO2 and dilute acidic metabolites, thereby mitigating phrenic nerve irritation. While these techniques have been validated in abdominal laparoscopic procedures such as cholecystectomy, their efficacy within the unique framework of vNOTES hysterectomy remains unexplored. vNOTES naturally utilizes lower pressures than traditional laparoscopy, yet the incidence of referred pain persists. There is currently a lack of high-level evidence determining whether the addition of a standardized saline was