[Safety and efficacy of temporary isolation technique using omentum combined with water balloon and biological mesh for empty pelvis after pelvic exenteration].

Objective: To investigate the safety and efficacy of a temporary isolation technique using omentum combined with an adjustable water balloon and biological mesh for preventing empty pelvis syndrome (EPS) following pelvic exenteration. Methods: A descriptive case series study was conducted. The clinical data of 15 patients who underwent pelvic exenteration at the Department of General Surgery, Jiangyin People's Hospital from January 2024 to June 2025 were retrospectively collected. All patients had a history of high-dose preoperative radiotherapy and varying degrees of pelvic infection. Intraoperatively, a "water balloon-omentum-biological mesh" triple isolation technique was adopted: an adjustable water balloon was placed in the pelvis for cavity filling; the pelvic inlet was covered with pedicled or free omentum at the cephalad aspect of the balloon, followed by coverage with a biological mesh to seal the pelvic inlet. The water balloon was removed 4 to 8 weeks postoperatively based on omental adhesion status and perineal wound healing. Perioperative indicators were observed. Postoperative pelvic CT scans at different time points were used to quantitatively assess changes in residual cavity volume and the location of the lowest loop of the small bowel. The incidence of EPS-related complications was also recorded. Results: All 15 patients successfully completed the surgery, among whom R0 resection was accomplished in 13 cases. The median intraoperative blood loss was 800 (range: 600-2000) ml. The overall postoperative complication rate was 6/15, with Clavien-Dindo grade ≥ III complications occurring in 3/15. Imaging follow-up showed that the residual cavity was completely filled by the water balloon at 1 week postoperatively. At 3 months postoperatively (after balloon removal), the residual cavity volume further decreased. CT re-examinations at 3 and 6 months after discharge revealed that the lowest point of the small bowel was located above the pelvic inlet in all patients. During a median follow-up period of 16(6-24) months, no cases of intestinal perforation or entero-cutaneous fistula caused by small bowel descent into the pelvis occurred, nor was any perineal hernia observed. Conclusions: For patients with a history of high-dose radiotherapy and pelvic infection, the temporary isolation technique using omentum combined with a water balloon and biological mesh does not physically eliminate the residual cavity permanently. However, it achieves progressive obliteration of the dead space and permanent isolation of the small bowel, fulfilling the goal of "functional elimination" of EPS. This technique represents a safe and effective strategy for pelvic floor reconstruction.