Endometriosis of the gastrointestinal system accounts for 5 to 12% of deep endometriosis cases¹. 90% infiltrates the rectum and the sigmoid (large bowel)². In most cases, the patients present with severe symptoms, such as the following: dyschezia (pain on opening the bowels), haematochezia (blood in the stools), bloating and change between constipation and diarrhoea. Those symptoms are, often, more intense before or during the menstrual cycle but may persist during the whole cycle. In some cases, they may be asymptomatic. They can be diagnosed pre-operatively by ultrasound or Magnetic Resonance Imaging (MRI).

The first line of management often is medical. However, many patients will eventually need surgery (e.g., side effects, failure of medical management, patient does not wish to take hormones, patient wishes to be pregnant, lesion that causes stenosis of bowel lumen and risk of bowel obstruction etc.). These operations are done with the help of colorectal surgeons with significant experience in bowel surgery.

Depending on where the lesion is, the surgical options (by laparoscopy) are:

1. Rectum: The most distal part of the colon (before the anus) with length of approximately 15 centimetres. Depending on the characteristics of the lesion, the surgeon can perform I. Rectal shaving³:  the surgeon shaves the rectal wall that is affected by endometriosis, without removing the affected bowel segment. It is commonly employed in more superficial lesions. II. Rectal disc excision⁴: it is preferred in ‘’deeper’’ rectal lesions, where the anterior rectal wall of the affected part is removed. There is an upper limit to the length of the rectum that can be excised (Around 4 centimetres). III. Segmental bowel resection⁴: In ‘’deep’’ bowel lesions that cannot be removed by rectal disc excision (for example due to size), this technique is useful. Generally, when technically feasible, approaches I and II are preferable to III as they are generally associated with better post-operative bowel function^5-7.
2. Sigmoid Colon: The part of the colon before the rectum (in the left lower quadrant). Endometriosis lesions can appear isolated (solitary nodules) or adherent to other organs (e.g., left ovary), and the surgical management generally includes removal of the affected part of the colon⁸.
3. Appendix: It is believed to be affected in up to 2.8% of patients with endometriosis⁹. It is managed by appendicectomy.
4. Ileum and caecum: The part of the terminal ileum (small bowel) and caecum (most proximal part of the large bowel) is affected, less often, by endometriosis. It is managed by surgical removal of the affected part.

It is our preference not to put prophylactic stomas, other than in few exceptions¹⁰. The post-operative hospital stay following surgery to the bowel is around 3 days, however, the surveillance is continued for 10 days post-operatively.

References:

1. Abo C, Moatassim S, Marty N, Saint Ghislain M, Huet E, Bridoux V, Tuech JJ, Roman H. Postoperative complications after bowel endometriosis surgery by  shaving, disc excision, or segmental resection: a three-arm comparative analysis of 364 consecutive cases. Fertil Steril. 2018 Jan;109(1):172-178.e1. doi:
2. Roman H, Ness J, Suciu N, et al. Are digestive symptoms in women presenting with pelvic endometriosis specific to lesion localizations? A preliminary prospective study. Hum Reprod. 2012;27(12):3440–3449.
3. Donnez J, Squifflet J. Complications, pregnancy and recurrence in a prospective series of 500 patients operated on by the shaving technique for deep rectovaginal endometriotic nodules. Hum Reprod 2010;25:1949–1958.
4. Fanfani F, Fagotti A, Gagliardi ML, Ruffo G, Ceccaroni M, Scambia G, Minelli L. Discoid or segmental rectosigmoid resection for deep infiltrating endometriosis: a case-control study. Fertil Steril 2010;94:444–449.
5. Roman H, Vassilieff M, Tuech JJ, Huet E, Savoye G, Marpeau L, Puscasiu L. Postoperative digestive function after radical versus conservative surgical philosophy for deep endometriosis infiltrating the rectum. Fertil Steril 2013.
6. Roman H, Milles M, Vassilieff M, Resch B, Tuech JJ, Huet E, Darwish B, Abo C. Long-term functional outcomes following colorectal resection versus shaving for rectal endometriosis. Am J Obstet Gynecol 2016;215:762.e1–762.e9.
7. Roman H, Bubenheim M, Huet E, Bridoux V, Zacharopoulou C, Daraï E, Collinet P, Tuech JJ. Conservative surgery versus colorectal resection in deep endometriosis infiltrating the rectum: a randomized trial. Hum Reprod. 2018 Jan 1;33(1):47-57.
8. Grigoriadis G, Hajdinak A, Forrestier D, Roman H, Solitary Endometriosis Nodules of the Sigmoid Colon: How to Approach Surgically, SEUD Congress, Athens, May 2022 (Video Presentation)
9. Al Oulaqi NS, Hefny AF, Joshi S, Salim K, Abu-Zidan FM. Endometriosis of the appendix. Afr Health Sci. 2008;8(3):196-198.
10. Horace Roman, Valerie Bridoux, Benjamin Merlot, et al. Could stoma reduce the risk of rectovaginal fistula in women with excision of deep endometriosis requiring concomitant vaginal and rectal sutures? A 363-patient comparative study. Authorea. July 01, 2020.