AB041. SOH24AB_105. Evaluating the use of pre-operative colonoscopy prior to combined colorectal/gynaecological surgery for stage IV endometriosis

Background: Less than 10% of patients with stage IV endometriosis and bowel involvement will have evidence of endometriosis intra-luminally. Colonoscopy is however still used in almost all patients pre-operatively. The purpose of this study is to correlate operative complexity and endoscopic findings in patients undergoing surgery for stage IV endometriosis in Tallaght University Hospital. Methods: Patients undergoing combined colorectal/gynaecological surgery for stage IV endometriosis with sigmoid and rectal involvement diagnosed on magnetic resonance imaging (MRI) were recorded in a prospectively maintained database. All patients undergoing combined surgery from October 2022 to October 2023 were included. A chart and electronic records review assessed their pre-operative endoscopic findings. Results: During the study period, 22 patients underwent combined colorectal/gynaecological surgery. The mean age was 42.7 years. Among the 22 patients, 18 (82%) underwent extensive pelvic adhesiolysis with excision of rectal deposits, while 2 (9%) required pelvic adhesiolysis with excision of deposits and stoma formation. Another 2 patients (9%) required low anterior resection with loop ileostomy formation. Pre-operative endoscopic assessment was conducted in 16 out of 22 patients (73%). Of these, 12 had no findings on colonoscopy, 4 had rectosigmoid angulation preventing scope progression. In total, 2 out of 12 patients (17%) who did not require stoma or resection had impassable angulation during endoscopy. Additionally, 2 out of 4 (50%) patients who had stoma or resection had impassable angulation (P=0.18). Conclusions: The use of endoscopy as a pre-operative investigation in patients with stage IV endometriosis and rectal involvement remains unclear. Based on this study endoscopy could be performed on an individualised basis.