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Deeply infiltrating endometriosis (Stage IV) can commonly involve the bowel. If you have found yourself on this page then it is likely that your gynaecologist suspects or indeed already knows that this is the case. When bowel involvement is suspected and surgery is being considered you may be referred to a colorectal surgeon to discuss bowel surgery. The following information is intended as an overview for you to read prior to any consultation and then to supplement the discussion you have with your surgeon.

Why do I need surgery for endometriosis?

Women looking at surgery for endometriosis can generally be divided in to two groups:


Endometriosis can reduce a woman's fertility. The goal of surgery here is to remove as much endometriosis as possible and free the ovaries so that they can be accessed for IVF. We tend to be more cautious about bowel surgery in this setting given that our main aim is fertility.


The most common symptom from endometriosis is pain. The goal of surgery in this setting is to remove as much endometriosis as possible to improve pain symptoms and is more likely to require bowel surgery.

What bowel symptoms can endometriosis cause?

Bowel symptoms from endometriosis can be quite variable. It may be that the endometriosis on the bowel is only recognised on a scan or on previous laparoscopy without it causing any specific bowel symptoms. The bowel symptoms from endometriosis can be very non-specific and common for many different bowel diseases. They may include pain with defecation, rectal bleeding, bloating, altered bowel habit (constipation or diarrhoea) and pelvic pain.

What investigations do I need to undergo?

Chances are by the time you have been referred to a colorectal surgeon you have already undergone multiple investigations for your endometriosis. This may include a pelvic MRI scan, deeply infiltrating endometriosis (DIE) pelvic ultrasound scan or a laparoscopy.

Depending on your bowel symptoms and scan findings, you may also need a colonoscopy prior to any surgery. This is usually performed for two reasons:

  1. Ensure there is no other bowel disease causing symptoms
  2. Assess the degree of endometriosis bowel involvement. Eg bleeding, narrowing

What bowel can be involved?

The short answer is any part! However in order of frequency the common areas are:
  1. Rectum. This is the last part of the bowel before the anal canal and sits behind the uterus, cervix and vagina
  2. Sigmoid colon. This is the last part of the colon before it reaches the rectum. It is often quite mobile and lies in the pelvis adjacent to the uterus.
  3. Caecum. This is the start of the colon in the right lower part of the abdomen. Depending on it's size it can lie adjacent to the uterus or right ovary.
  4. Small bowel. You have a lot of small bowel (3-5m). Small bowel usually is very mobile and can sit in the pelvis adjacent to all the pelvic organs.

What surgery may be required?

These operations are usually performed as combined cases with your gynaecologist and colorectal surgeon. We will assess your symptoms and investigations prior to surgery to give you as best an idea as possible as to potential involvement. However despite the advances in technology with multiple scans it is often difficult to predict the need for and extent of bowel surgery required. Whilst scans can demonstrate endometriosis attached to bowel, they do not necessarily show how easily it can be separated off. The operation will usually commence with either your gynaecologist or colorectal surgeon separating bowel away from uterus, cervix, ovaries and fallopian tubes. Whilst it is usually possible to achieve this, there may be endometriosis remaining on the bowel that needs to be excised. Depending on the location and size of the endometriotic deposit, the following are some of the options for surgery:

Shave excision

This is usually only reserved for superficial deposits that are not clearly infiltrating (growing in to) the bowel wall. In performing this, care needs to be taken not to damage the bowel wall which can lead to perforation.

Disc excision

This is a procedure that can only be performed on the rectum. If there is only a small deposit on the front of the rectum (<2cm) it may be possible to use a special stapling device to remove just the endometriosis with surrounding rectal wall. It is difficult to perform this for deposits which are larger than 2cm or involving the side of the bowel.

Bowel resection

For larger, multiple or other areas of bowel you may require a bowel resection. The following operations are frequently required:
  1. Anterior resection. This is the term given to removal of part or all of the rectum. The location of the endometriosis will determine how much rectum needs to be removed. The colon is then rejoined (anastomosed) to the remaining rectum.
  2. Sigmoid resection. If the endometriosis just involves a short segment of sigmoid, then it is possible to perform a short wedge excision. This is reliant on a normal, uninvolved rectum
  3. Right hemicolectomy. This involves removing the end of the small bowel and start of the large bowel. This is commonly performed when endometriosis involves the caecum (start of large bowel). The small bowel is then rejoined to the right colon.
  4. Small bowel resection. A short segment of small bowel may need to be removed.

Will I need a stoma (bag)?

This is a question that frequently is asked and understandably one that patients worry about. There would usually only be two scenarios when a stoma may be required:
  1. There is extensive endometriosis that has necessitated the removal of the entire rectum. In this setting, whilst the colon can be rejoined, the risk of a leak from this join is unacceptably high and in order to protect that join we need to temporarily divert bowel content away from it by creating a stoma. This happens infrequently.
  2. There is a leak from a join in the bowel in the post-operative period requiring another operation.
If you do require a stoma we make every effort to ensure that a stoma is temporary. There is a very remote risk that you may require a permanent stoma.

What are the risks of surgery?

Bowel surgery is major surgery and carries risks. Whilst it is not possible to list all potential complications the following are the more important and common ones:


Bleeding can occur from any surgery. If the bleeding is excessive you may require a blood transfusion.


Infections can happen in the wound or deeper within the abdomen or pelvis. It may just require antibiotics for the milder infections, or further operations for the more severe infections.

Anastomotic leak

This is the complication that as colorectal surgeons we worry most about. When a section of bowel is removed we (usually) join the two ends together. This is achieved with either stitches or special staples. There is a chance that the join will not heal successfully and bowel content can leak through the join. The more common joins without the need for a stoma have a risk of 1-2%. If there is a leak in the post operative period you may require further surgery and potentially a stoma (bag).

Ureteric injury

The ureter is a tube that runs from each kidney to the bladder and drains urine. There is a very low risk of damage to the ureter either from excision of endometriosis or a bowel resection. This may be noticed at the time or in the post operative period requiring further procedures.


No one likes to talk about this, but major surgery carries a risk of serious complications and death. Factors that can increase the risk are age and pre-existing medical conditions.

What will my bowel function be like after surgery?

The only thing predictable about someone's bowel habit after bowel surgery is that it is unpredictable. Altered bowel habit is common after rectal surgery and less common after small bowel surgery or right hemicolectomy. Removal of part or all of the rectum can significantly alter someone's bowel function. The rectum ordinarily acts as a reservoir for faeces that allows us to defer defecation. When part or all of the rectum is removed it is replaced with colon. Colon does not have the same expansile capacity of the rectum and thus bowel frequency and urgency is common. Other symptoms can include diarrhoea, constipation and rarely incontinence. Any number of these symptoms are common in the immediate post operative period. Most will notice significant improvement in the first few months and continued improvement up to and beyond 12 months. It is difficult to predict or explain why two patients undergoing the same uncomplicated operation can have vastly different bowel function afterwards. There are medications that can be used to try and improve bowel function.

Last updated May 2017

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