Surgery for Bowel Endometriosis

Diagnosis begins with a detailed medical and gynaecological history, including the type of bowel symptoms experienced and whether they change during the menstrual cycle. A pelvic examination may also be performed where appropriate to identify tenderness, reduced organ mobility or findings suggestive of deep endometriosis.

Specialist transvaginal ultrasound can help identify and assess deep endometriosis involving the bowel, while MRI may be used to map the location and extent of disease and its relationship with surrounding pelvic structures. When surgery is performed, the affected areas can be directly assessed and removed tissue may be sent for histological examination.

Colonoscopy is not routinely used to diagnose bowel endometriosis because the disease generally develops on the outside of the bowel and grows inward, while colonoscopy primarily examines the inner bowel lining. It may, however, be used when clinically indicated to investigate other possible causes of bowel symptoms.

Not everyone diagnosed with bowel endometriosis requires an operation. Surgery may be considered when symptoms are significant, medical treatment has not provided adequate control or the disease is causing substantial bowel involvement. It may be appropriate for women with:

• Persistent or severe pain associated with bowel endometriosis
• Bowel symptoms that significantly interfere with daily activities or quality of life
• Symptoms that remain troublesome despite appropriate medical treatment
• Deep endometriosis significantly affecting the bowel wall
• Bowel narrowing caused by endometriosis or evidence of bowel obstruction
• Extensive endometriosis affecting the bowel together with other pelvic structures
• Fertility concerns where surgical treatment is considered appropriate as part of individual fertility management
• Clinical circumstances in which the expected benefits of surgery outweigh the potential risks

The surgical technique is selected according to factors such as the size, depth, number and location of bowel lesions and the degree to which the bowel wall is affected. The main surgical techniques include:

• Bowel Shaving — Bowel shaving involves carefully removing endometriosis from the surface of the bowel without removing a full-thickness section of the bowel wall. It may be appropriate when the disease can be adequately excised without opening or removing a segment of bowel.
• Disc Excision — Disc excision removes a localised, full-thickness area of the bowel wall affected by deeper endometriosis. The opening in the bowel is then securely closed, allowing the remainder of that section of bowel to be preserved.
• Segmental Bowel Resection — Segmental resection involves removing a section of bowel affected by endometriosis and reconnecting the healthy ends of the bowel. It may be considered for more extensive disease, such as larger or multiple lesions, significant infiltration of the bowel wall or substantial narrowing of the bowel.

Bowel endometriosis surgery is commonly performed using a minimally invasive approach, although the technique depends on the extent and complexity of the disease and the bowel procedure required.

• Laparoscopic Surgery — small abdominal incisions are used to introduce a camera and specialised instruments, allowing the surgeon to identify and remove endometriosis affecting the bowel and other pelvic structures.
• Robotic-assisted Surgery — the surgeon controls robotic instruments from a console while viewing the operative area through magnified 3D visualisation. This minimally invasive approach may be used in selected cases.
• Open Surgery — a larger abdominal incision may occasionally be required when disease is particularly extensive or complex, or when minimally invasive surgery cannot be performed or completed safely.

Because bowel endometriosis may involve both gynaecological and colorectal structures, surgical planning may involve a multidisciplinary team. A colorectal surgeon may participate when more extensive bowel surgery, such as disc excision or segmental resection, is anticipated.

The exact procedure depends on the location, depth and extent of bowel endometriosis. Surgery is performed under general anaesthesia and may also involve treatment of endometriosis elsewhere in the pelvis.

The extent of bowel surgery can vary considerably between patients, making careful pre-operative planning particularly important. Factors to consider include:

• Location and Extent of Disease — the size, depth, number and location of bowel lesions help determine the most appropriate surgical technique.
• Degree of Bowel Narrowing — significant narrowing may influence whether more extensive bowel surgery is required.
• Type of Bowel Surgery — treatment may involve bowel shaving, disc excision or segmental resection depending on the disease.
• Bowel Reconnection — segmental resection requires the healthy ends of the bowel to be reconnected after the affected section is removed.
• Possibility of a Temporary Stoma — a temporary stoma may occasionally be required in selected complex cases to protect a bowel connection or manage surgical risk.
• Other Pelvic Disease — endometriosis affecting the ovaries, uterus, bladder, ureters or other structures may require treatment during the same operation.
• Fertility Plans — future pregnancy goals should be considered when planning treatment for extensive endometriosis.
• Possibility of Recurrence — endometriosis or associated symptoms can persist or return after surgery.
• Recovery Requirements — recovery varies according to whether limited bowel treatment or more extensive resection is performed.
• Multidisciplinary Care — colorectal or other surgical specialists may be involved when the disease affects multiple organs.
• Benefits and Risks — the expected improvement from surgery should be considered alongside bowel-specific and general surgical risks.

Risks vary substantially according to the extent of disease and the procedure performed. Superficial bowel shaving generally involves different risks from full-thickness disc excision or segmental bowel resection.

• Bleeding — bleeding can occur during or after surgery and may occasionally require additional treatment.
• Infection — infection may develop at the surgical site, within the pelvis or elsewhere following surgery.
• Blood Clots — surgery can increase the risk of blood clots forming in the legs or travelling to the lungs.
• Anaesthetic Complications — general anaesthesia carries potential risks that vary according to your overall health.
• Injury to Nearby Structures — the bladder, ureters, nerves, blood vessels or other pelvic structures may be injured during complex surgery.
• Bowel Leak — leakage can occur from an area of bowel that has been repaired or reconnected and may require further treatment or surgery.
• Pelvic Infection or Abscess — infection or a collection of infected fluid may develop within the pelvis following bowel surgery.
• Changes in Bowel Function — bowel habits may temporarily change after surgery, particularly following bowel resection.
• Urinary Problems — temporary difficulty emptying the bladder or other urinary dysfunction may occur, particularly after extensive deep pelvic surgery.
• Temporary Stoma — a temporary stoma may occasionally be necessary in selected complex cases.
• Adhesion Formation — internal scar tissue can develop as part of the healing process after abdominal or pelvic surgery.
• Conversion to Open Surgery — minimally invasive surgery may occasionally need to be converted to an open procedure for safe completion.
• Persistent or Recurrent Symptoms — pain, bowel symptoms or endometriosis may persist or recur despite surgery.

Preparation helps establish the extent of bowel and pelvic disease, determine the planned procedure and ensure you are medically ready for surgery. Depending on your individual circumstances, this may include:

• Medical and Gynaecological Assessment — your symptoms, overall health, medical history and previous endometriosis treatments will be reviewed.
• Review of Bowel Symptoms — the nature, severity and timing of bowel symptoms will be assessed to help guide treatment planning.
• Imaging Investigations — specialist ultrasound, MRI or other imaging may be used to map bowel endometriosis and assess surrounding structures.
• Pre-operative Tests — blood tests and other investigations may be arranged to assess your general health before surgery.
• Medication Review — current medications and supplements will be reviewed, with instructions provided if any need to be adjusted or temporarily stopped.
• Anaesthetic Assessment — your medical history and general health will be assessed before general anaesthesia.
• Surgical Planning — the anticipated bowel procedure and treatment of endometriosis elsewhere in the pelvis will be discussed.
• Colorectal Assessment — a colorectal surgeon may be involved when more extensive bowel surgery is anticipated.
• Fertility Discussion — future pregnancy plans may be considered when determining the overall treatment approach.
• Fasting Instructions — you will receive instructions about when to stop eating and drinking before surgery.
• Bowel Preparation — bowel preparation may be recommended for certain planned bowel procedures, but it is not required for every patient.
• Informed Consent — the expected procedure, possible additional surgery, potential benefits, risks and alternatives will be discussed before consent.

After surgery, you will be monitored as you recover from general anaesthesia and given appropriate pain relief. You will usually be encouraged to start moving when safe, while eating and drinking are gradually resumed according to your recovery and the bowel procedure performed. Your surgical team will also monitor bowel and urinary function and provide instructions for caring for your incisions.

The hospital stay and early recovery depend considerably on the extent of surgery. Recovery after bowel shaving may differ from recovery after full-thickness disc excision or segmental bowel resection. Before discharge, you will receive guidance on diet, physical activity, wound care and symptoms that require medical attention, with follow-up arranged to assess your recovery.

Surgery removes the bowel endometriosis identified and treated during the operation, but it does not guarantee a permanent cure. Endometriosis can persist or recur, and symptoms may also return over time.

Further management depends on your symptoms, reproductive plans and individual circumstances. Some patients may benefit from ongoing medical treatment after surgery, while further surgical treatment may occasionally be considered if significant disease or symptoms recur.

Bowel endometriosis occurs when endometriosis affects the bowel, most commonly the rectum and rectosigmoid region. Surgery may be considered when the condition causes significant pain or bowel symptoms, results in substantial bowel narrowing or does not respond adequately to conservative treatment.

Depending on the depth and extent of disease, treatment may involve bowel shaving, disc excision or segmental bowel resection, usually through a minimally invasive laparoscopic or robotic-assisted approach where appropriate. The aim of surgery is to remove endometriosis, relieve symptoms and address bowel involvement while avoiding unnecessary bowel resection where possible.

However, bowel endometriosis surgery can be complex, particularly when deep disease affects several pelvic structures, and treatment must balance potential benefits against bowel-specific surgical risks and the possibility of recurrence.

If you are considering surgery for bowel endometriosis in Singapore, schedule a consultation with Dr Ma Li to discuss your symptoms, the extent of your condition and the surgical approach most appropriate for your needs.