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Bowel dysfunction after surgery

25 March 2021
Volume 30 · Issue 6


The functions of the lower parts of the bowel, namely the colon and rectum, are predominantly the absorption of fluids and elimination of faeces and flatus. Bowel surgery may be carried out in the treatment of colorectal cancer, inflammatory bowel disease or diverticular disease, and may involve the formation of a permanent or temporary stoma. The type of colorectal surgery carried out depends on the condition and where the problem occurs. Surgery can alter not only the bowel's anatomy but also its functioning. Bowel dysfunction can manifest as constipation, faecal incontinence or diarrhoea. Nurses are well placed to assist patients to resolve many of these problems as well as stoma issues.

Caring for people with bowel dysfunction can be complicated as well as expensive. The Bowel Interest Group (2020) reported that more than £160 000 000 was spent treating people with constipation in the UK in 1 year, and constipation is just one type of bowel dysfunction. Bowel dysfunction can occur for many reasons and is common in the general population, but is more often reported by people after colorectal surgery (Sperber et al, 2020).

The bowel

The function of the gastrointestinal tract is to ingest and digest food and fluids, absorb nutrients and eliminate any waste products (Tortora and Derrickson, 2014). Ingestion generally occurs via the mouth. Digestion occurs in the stomach and upper small bowel. Absorption occurs mainly in the small bowel where several litres of ingested and secreted fluids are absorbed. The nutrients from the diet are absorbed into the bloodstream and lymphatic system to be used within the body.

The functions of the lower parts of the bowel, namely the colon and rectum, are predominantly the absorption of fluids and elimination of faeces and flatus. It is important to understand how the bowel functions in health to understand how surgery may alter not just its anatomy, but also its function.

As faeces pass from the small bowel (terminal ileum) into the colon (caecum) via the ileocaecal valve, they are loose, with a lot of fluid still retained in them. The ileocaecal valve regulates the passage of faeces from the small bowel to the large bowel. The faeces move along the colon towards the rectum, through muscle contractions within the bowel wall. These muscle contractions are termed peristalsis and mass movements. As faeces are propelled through the colon, there is an additional absorption of fluids, which thickens the consistency of the faeces. When the faeces reach the rectum, they should be a soft, brown, formed, sausage-shaped stool. Faeces are stored within the rectum until they are passed from the body into the toilet (Askari, 2016).

There is no precise normal pattern of defecation, but it is common to pass stool daily, within a range of three motions passed in a week to three passed in a day.

The function of the bowel may be altered for a number of reasons, including bowel surgery.

Bowel diseases that might result in surgery

Bowel surgery can be undertaken for a number of reasons. This may include for diseases such as colorectal cancer, inflammatory bowel disease or diverticular disease.

Colorectal cancer can be described as a growth of abnormal cells within the colon or rectal wall. Colorectal cancers also have the potential to metastasise to different areas of the body. Colorectal cancer commonly spreads to the liver or, alternatively, it can grow into nearby structures such as the bladder (Bunni and Moran, 2019).

Colorectal cancer is the fourth most common cancer diagnosed in the UK, with about 1 in 20 people developing a colorectal cancer in their lifetime (Office for National Statistics, 2019). Most people who develop a colorectal cancer are aged over 60 years. If the colorectal cancer is caught early before it spreads, the survival rate is high (over 95%) but, if the cancer presents late, the chances of survival are reduced to about 40% at a year after diagnosis (Cancer Research UK, 2019). Symptoms that patients with colorectal cancer might report include a change in bowel habit and rectal bleeding.

Inflammatory bowel disease is a term that includes two diseases: ulcerative colitis and Crohn's disease.

Ulcerative colitis can be seen as a disease of the colon and rectum, resulting in periods of disease remission and relapse. About one in 420 people in the UK have been diagnosed with ulcerative colitis (Crohn's and Colitis UK, 2017). A symptom a patient with ulcerative colitis might report is the urgent need to pass faeces (urgency) and an objective sign of ulcerative colitis is diarrhoea.

Crohn's disease can similarly be described as a condition with periods of disease flare or remission. Crohn's disease differs from ulcerative colitis in that it can affect any part of the gastrointestinal tract from mouth to anus whereas ulcerative colitis affects only the colon and rectum. About one in every 650 people in the UK has Crohn's disease and it is diagnosed most commonly in younger people aged 10-40 years (Crohn's and Colitis UK, 2016b). Symptoms that a patient with Crohn's disease might report include abdominal pain or a loss of appetite and objective signs includes diarrhoea or weight loss.

Finally, diverticular disease is typically a disease of the older person in the western world. It is uncertain what causes diverticular disease, but it is thought that the small pockets that form in the colon, most commonly within the sigmoid colon, occur as a result of pressure on the bowel walls possibly from constipation. There can be one pocket (diverticulum) or many diverticula present in the colon. These pockets can fill with faeces and cause issues such as abdominal pain because of inflammation, which is termed diverticulitis. If a diverticulum becomes perforated, faeces can leak through this hole in the colon into the abdominal cavity, potentially causing life-threatening peritonitis that may require emergency surgery (NICE, 2021).


Surgical treatment for the above diseases is to remove the affected area of the bowel. For people with cancer, surgery is often the treatment of choice. Surgery for people with a cancer may or may not be accompanied by chemotherapy and/or radiotherapy. Surgical excision of the bowel is not usually the first-line treatment option for people with Crohn's disease and ulcerative colitis; medication is often tried first. Surgery is undertaken if medication is unsuccessful in achieving a good quality of life and symptom resolution. Most people with diverticular disease do not require surgery but, if they do, this may be carried out as an emergency. Surgery might be indicated if there is a perforation of the diverticula resulting in peritonitis or if a perforated diverticulum has formed a colovesical fistula into the bladder, for example.

There are a number of colorectal operations that may be undertaken for people with these three diseases. The operations that will be described are:

  • Abdominoperineal excision of the rectum and permanent colostomy (APER)
  • Anterior resection with or without total mesorectal excision (TME)
  • Hartmann's procedure and temporary colostomy
  • Hemicolectomy
  • Total/subtotal colectomy with or without temporary ileostomy
  • Panproctocolectomy and permanent ileostomy.

An APER is the removal of the rectum, anal canal and anus, which requires the formation of a permanent colostomy to pass faeces and flatus. An APER can be formed for a variety of reasons including for rectal cancer (Swinson and Seymour, 2012) or with perianal Crohn's disease.

An anterior resection is the removal of part or most of the rectum, but the ends of the bowel are anastomosed (joined) and a permanent colostomy is not needed. For cancers that are lower in the rectum, the anterior resection can be extended to include the area around the rectum, which is termed the mesorectum (TME). A TME reduces the risk of cancer recurrence but, unfortunately, it increases the risk of postoperative bowel dysfunction (Bunni and Moran, 2019). An anterior resection and TME will in most cases be undertaken with the formation of a temporary ileostomy. This requires additional surgery to reverse or close the ileostomy sometime in the future.

A Hartmann's procedure is the removal of the sigmoid colon; with the descending colon formed into an end colostomy. In most cases, the rectum is closed with staples and left inside the body. A Hartmann's procedure is most commonly undertaken to treat a person with peritonitis as a result of a perforated diverticulum (NICE, 2020). A Hartmann's procedure might also be performed for a person with a colorectal cancer. The colostomy is theoretically temporary but for many people the stoma is never reversed. There are a number of reasons that a stoma is not reversed; most commonly this is because of patient choice or because patients have comorbidities that make additional surgery a risk (Hallam et al, 2018).

A hemicolectomy is the removal of half of the colon and the remaining ends are usually anastomosed. In reality, exactly half of the colon is not removed. A left hemicolectomy is the removal of the descending colon (Association of Coloproctology of Great Britain and Ireland, 2021), which may be performed in a person with a cancer or Crohn's disease in the descending colon. A right hemicolectomy is a resection of the ascending colon and anastomosis of the terminal ileum to the ascending or transverse colon. A right hemicolectomy also includes the resection of the ileocaecal valve. A right hemicolectomy might be performed in a person with a cancer in the ascending colon. In a person with terminal ileal Crohn's disease, a right hemicolectomy or an ileocaecal resection (less of the colon is resected) might be undertaken. Another reason for a left or right hemicolectomy is trauma.

A total colectomy is the removal of the entire colon and, although it is possible to join the small bowel (ileum) and rectum, most commonly a temporary ileostomy is formed. A subtotal colectomy is removal of most of the colon; this might be the removal of the ascending colon to the sigmoid colon, leaving the sigmoid colon and rectum. A colectomy is most commonly performed for a person with inflammatory bowel disease (Clark, 2010).

Finally, a panproctocolectomy is the removal of the colon, rectum and anus, which requires the formation of a permanent ileostomy. This operation is most commonly performed for a person with inflammatory bowel disease (Clark, 2010).

A bowel resection will change the anatomical structure of the bowel; surgery can also alter how the bowel functions. After colorectal surgery, bowel dysfunction can occur. This can be down to a number of reasons, including damage to the pelvic floor or to the nerves that are needed for bowel function. This can result in impaired anal continence.

Bowel dysfunction

The route of faeces elimination will change from the anus to a stoma if one is formed during colorectal surgery. Changes to bowel function occur when a faecal output stoma, such as a colostomy or ileostomy, is formed. The formation of a colostomy will mean that the faeces and flatus will pass without voluntary control into a colostomy appliance; the frequency and consistency might be similar to that encountered before colostomy formation. An ileostomy will pass looser faeces and flatus, also without voluntary control; however, there will be more frequent passage, which will necessitate an ileostomy appliance being emptied about 4-6 times each day.

The focus of the section below is on changes to bowel function when faeces are passed through the anus after colorectal surgery. Bowel dysfunction can manifest as constipation, anal incontinence or diarrhoea (NICE, 2020). Bowel dysfunction is more likely to occur if there is a large bowel resection such as a colectomy or if most of the rectum is resected, as happens in a TME.

It is important to note that bowel dysfunction is common in the general population. In an international survey of more than 70 000 people in over 30 countries including the UK, about one in 10 people reported that they had constipation and one in 20 people experienced diarrhoea (Sperber et al, 2020). Those surveyed did not include people with a known bowel disease or following colorectal surgery, and these numbers would be expected to be higher for people after colorectal surgery.

Bowel dysfunction can occur following the removal of the ileocaecal valve. Without the ileocaecal valve, the regulation of loose faeces from the small bowel into the colon no longer occurs. If the ileocaecal valve has been removed, there can be a problem with bile salts not being absorbed in the terminal ileum; this is termed bile salt malabsorption (NICE, 2013). When an excess of bile salts enter the colon, this can lead to a number of problems that include explosive diarrhoea, abdominal cramp, flatulence, urgency, frequency and unpredictable bowel habit (Adio and Burch, 2020). For most people, having the ileocaecal valve removed during a right hemicolectomy does not result in severe symptoms, but faeces might be looser than before the operation.

Loose faeces are more common if a large section of the colon is removed such as in a subtotal colectomy, a hemicolectomy or a sigmoid colectomy. It is possible that the faeces will be passed in larger volumes and/or more frequently than before the colonic resection. Looser faeces are more common if the entire colon is removed. Having a total colectomy will reduce the absorptive capacity of fluid from the bowel lumen. This translates into an additional 1 litre of fluid remaining in the faeces. Over time, the bowel will adapt and absorb more fluid, which reduces the faecal volume. Passing loose faecal matter may potentially compromise bowel control, resulting in incontinence (O'Brien, 2012).

Finally, thinking about the storage role of the rectum, if part, most or the entire rectum is resected, this can result in a loss in ability to ‘hold on’ once the urge to defecate is felt. An inability to defer defecation can result in urgency and possibly faecal incontinence. If rectal storage capacity is reduced, this space will be more quickly filled with only small amounts of faeces than before surgery. This means that more frequent trips to the toilet are required to pass small amounts of faeces; this is termed increased bowel frequency (Taylor and Bradshaw, 2014).

Alternatively, some people have evacuation problems that present with difficulty passing faeces. A patient might report that their rectum does not feel empty after defecation or, alternatively, the urge to defecate is felt but the muscles are uncoordinated, resulting in difficulty passing the faeces.

For people who have their rectum removed as part of an anterior resection, the various bowel dysfunction terms have been collated under the term low anterior resection syndrome (LARS). A new definition for LARS has been made by international consensus. LARS is defined as symptoms that occur after an anterior resection resulting in at least one of eight bowel symptoms; these symptoms then result in one or more of eight consequences (Keane et al, 2020). Symptoms include variable, unpredictable bowel function, urgency, increased bowel frequency and incontinence; consequences include a preoccupation with bowel function, as well as changes in relationships, intimacy and roles.

A number of changes to bowel function can occur as a result of bowel surgery. It is important to understand the issues that people may experience after a stoma is reversed and be able to advise them. Nurses are well placed to assist patients to resolve many of these issues.

Nursing care

It is essential to be able to assess bowel problems to be able to address them. Useful questions the nurse can ask during an assessment include: what is the main problem? What is the goal of the patient? (Swatton, 2017). After a full assessment of the bowel dysfunction, the nurse is able to determine the problem and thus choose a treatment option. Often, a number of nursing interventions are required. Treatment can include diet, medication, pelvic floor exercises and wearing a pad. Treatment will depend on the reported problem, such as loose stool, difficulty in evacuating faeces or incontinence.

Loose stool may present a number of nursing issues, such as incontinence or perianal skin damage. Treatment for loose stool might include medication such as loperamide; this drug inhibits peristalsis so is used to thicken the faecal output. It is also essential to encourage good perianal skin care, as more frequent passage of loose faeces can lead to erosion of the skin around the anus. Skin damage can occur as a result of frequent cleaning after bowel actions or enzymes within the faeces. To protect and hydrate perianal skin, a barrier cream may be useful (Norton and Chelvanayagam, 2004; Collins and Bradshaw, 2017). Another way to manage loose stool is to amend the diet, making changes such as using white carbohydrates instead of wholemeal or wholewheat versions. Depending on how loose the faeces are, it might be important to add salt to the diet to make up for the sodium lost. It is important to remember that the bowel can adapt over time and this can take up to about 2 years, so the patient's needs and treatments might change.

There are some similarities in treatments for faecal incontinence and loose faeces. Loperamide and dietary manipulation can be useful if there is loose stool that is contributing to the incontinence. For some people, adding fibre can thicken and add bulk to the faecal matter, which can assist in improving continence. Wearing a pad and protecting the perianal skin is important. Onward referral to specialist services such as continence services or biofeedback (Collins and Bradshaw, 2017) may be necessary for people with issues that do not respond to these more simple treatment options.

For people who report urgency and frequency, symptoms often improve over time but initially it is important to consider thickening the faeces to reduce these symptoms. Urgency can be addressed by gradually increasing the capacity of the rectum. For some people who fail on some of the more simple treatment options such as diet and medication, there are other options such as rectal irrigation. Irrigation has been shown to be useful for people with increased frequency (Lyon, 2016). The use of rectal irrigation may need to be following a referral to continence or biofeedback services.

Evacuation issues may be assisted by exercising the muscles related to defecation. It is possible that bowel retraining is needed. People might need to be reminded about ideal positions and techniques for using the toilet (Collins and Bradshaw, 2016). It can be useful to encourage exercises, such as those to strengthen the anal sphincter and pelvic floor muscles. Pelvic floor exercises can also be useful to help with urgency and faecal incontinence.

In some people, these measures do not work. For carefully selected patients with faecal incontinence or constipation, neuromodulation can be useful. This involves sacral nerve stimulation, where electrical pulses stimulate nerves to improve defecation (Maeda and Vaizey, 2016).


Bowel diseases often result in changes to bowel function and the surgical treatment for bowel diseases such as colorectal cancer, inflammatory bowel disease and diverticular disease can also change bowel function. These changes in function can cause problems including urgency and faecal incontinence. It is important for nurses to assess bowel dysfunction after colorectal surgery to enable treatment to be start or a referral to be made.

Key Points

  • The function of the gastrointestinal tract is to ingest, digest, absorb nutrients and fluid and eliminate waste products
  • Bowel surgery can be carried out for reasons including colorectal cancer, inflammatory bowel disease or diverticular disease, and may involve the formation of a stoma
  • Colorectal cancer will affect about one in 20 people, but survival is good if it is caught early
  • Ulcerative colitis is a disease of the colon and rectum; people might present to the nurse with diarrhoea
  • Crohn's disease affects any part of the gastrointestinal tract from the mouth to the anus and can cause abdominal pain and diarrhoea
  • If colorectal surgery includes the removal of part of the colon or rectum, this may result in changes in bowel function; patients may have an urgent need to find a toilet once they feel the urge to pass a bowel motion

CPD reflective questions

  • When reflecting on discharge advice after colorectal surgery, what advice can be provided to cope with any potential changes in bowel function?
  • Considering preoperative bowel dysfunction and how postoperative bowel changes may also occur for people with inflammatory bowel disease, how can you reassure them this is not a flare of their disease?
  • What considerations could be useful for patients following colorectal surgery while they are in hospital recovering from their surgery?