Abdominal stomas

The word “stoma” is derived from the Greek for mouth and describes an artificial opening in the abdominal wall, fashioned by a surgeon to divert the flow of faeces or urine. An estimated 100 000 people in the United Kingdom have a stoma, and about 65% of these stomas are permanent.¹ Medical students are often asked to examine patients with abdominal stomas during bedside surgical teaching and in final bachelor of medicine examinations. Here we attempt to demystify the construction and function of these often life saving procedures.

The most common stomas are colostomy (end or loop), ileostomy (end, loop, or end-loop), double barrel, and urostomy (ileal conduit). Stomas that involve bowel are created principally if no physical, distal bowel is present (for example, surgical resection of rectum and anus); if no normally functioning, distal bowel is present (for example, incontinence); if the distal bowel needs to be defunctioned or rested (for example, distal fistula in Crohn’s disease, distal surgical anastomosis, and inoperable rectal cancer); or if a primary anastomosis would be unsafe to perform (for example, in acute diverticulitis with peritontitis).

End colostomy

This procedure is most commonly performed to manage carcinoma of the lower rectum or anus, diverticular disease, and rare cases of faecal incontinence that do not respond to medical management.

For example, a very low rectal cancer will require resection of the rectum and anus (abdominoperineal excision of rectum). The remaining descending and sigmoid colon is mobilised and the cut end brought to the abdominal surface at an opening about 2 cm across. This is usually sited in the left iliac fossa (fig 1).

Fig 1 Abdominoperineal excision of the rectum

If the anus, rectum, and a portion of the lower colon have not been removed, as in Hartmann’s procedure, two outcomes are possible. In the first, the distal, non-functioning part of the colon and the rectum can be stapled or sewn closed and left inside the abdomen as a rectal stump (fig 2). The proximal colon is then taken out as an end colostomy. Because the rectum has not been removed, the urge to have a bowel movement may occur. Mucus and some old stool, if present, will be passed. If the colostomy is temporary, a second operation is needed to reconnect the two ends of the bowel.

Fig 2 Hartmann’s procedure

Less commonly, two separate stomas may be created. One stoma is the exit of the functioning part of the colon through which stool and gas pass. The second stoma opens into the non-functioning portion of the colon and rectum and is called a mucous fistula (fig 3). The second stoma is usually small, flat, pink-red in colour, and moist, and it produces only mucus.

Fig 3 Hartmann’s procedure and mucous fistula

Loop colostomy

A loop colostomy was traditionally created to defunction an inflamed sigmoid in diverticular disease or to defunction a distal anastomosis.² It has largely been replaced by loop ileostomy.

A loop of colon is brought to the surface of the body and may be supported on a rod, which is removed after about five days. The bowel wall is partially cut to produce two openings—of an afferent limb and an efferent limb (fig 4). The opening of the afferent limb leads to the functioning part of the colon, through which stool and gas pass out. The opening of the efferent limb leads into the non-functioning part of the colon. The stoma site was usually high on the abdomen above the waistline because the transverse colon was commonly used.

Fig 4 Loop colostomy

Currently, loop colostomies are more often fashioned from the sigmoid colon to defunction the rectum (for example, in cancer) or anus (for example, in incontinence). A loop colostomy may be temporary or permanent.

End ileostomy

When the entire colon, rectum, and anus must be removed (panproctocolectomy) an end ileostomy must be employed. This occurs most commonly in severe ulcerative colitis but also in familial polyposis and some cases of colorectal cancer (for example, hereditary non-polyposis colorectal cancer).

The ileum is resected just short of its junction with the caecum, and 6-7 cm of the small bowel is brought through the abdominal wall, usually in the right iliac fossa (fig 5). It is everted to form a spout and then sutured to the bowel wall (fig 6). This technique of turning the small bowel inside out to create a spout was pioneered in the 1950s by the English surgeon Bryan Nicholas Brooke to protect the skin from the irritating content of the ileal fluid.

Fig 5 End ileostomy

Fig 6 An everted spout stoma (ileostomy) and a flush stoma (colostomy)

After a panproctocolectomy the ileostomy is permanent. Temporary end ileostomy is often used after an emergency subtotal colectomy, which leaves part of the sigmoid colon and rectum left in place; for acute ulcerative colitis; acute ischaemic bowel; or neoplastic obstruction of the sigmoid colon.

Loop ileostomy

This type of stoma allows for defunctioning of an obstructed colon (for example, in cancer), defunctioning of a distal anastomosis (for example, after resection and primary anastomosis either as an emergency or after radiotherapy), or defunctioning of the anus (for example, in incontinence or perineal involvement in Crohn’s disease). Loop ileostomy has largely replaced loop colostomy because it is easier to site, less bulky, and easier to surgically close.³

A loop ileostomy has two openings, and most are temporary. Formation of the loop ileostomy is similar to a loop colostomy although the afferent limb must be everted or “Brooked” as in end ileostomy (fig 6).

End-loop ileostomy

This less commonly performed procedure is used when an end ileostomy cannot be fashioned safely because the patient is obese or because of unfavourable mesenteric anatomy. The formation of this stoma is similar to a loop ileostomy, but the efferent limb is short and blind ended. On inspection at the bedside this type of stoma is indistiguishable from a loop ileostomy.

Double barrel stoma

When the caecum is removed, the surgeon might create a double barrel stoma. In essence, this is an end ileostomy (small bowel) and a mucous fistula (the remaining colon) sited beside each other. On examination this will look almost identical to a loop ileostomy, however, closer inspection will show two separate stomas.

Urostomy

This is a general term for the surgical diversion of the urinary tract. The main reasons for a urostomy are cancer of the bladder, neuropathic bladder, and resistant urinary incontinence.

The bladder is usually removed, but this may depend on the underlying condition. Formation of an ileal conduit is the most common procedure, which constitutes isolation of a segment of ileum. One end of the ileum is closed and the two ureters are anastomosed to it. Finally, the open end of ileum is brought out onto the skin as an everted spout and will look similar to an end ileostomy (figs 5 and 6). Urine drains almost constantly from the kidneys through the ureters and ileal conduit into a stoma bag.

Stoma bags

Stoma bags are of two main types. Single piece systems stick straight on to the patient’s skin. Two piece systems have a separate base (a flange) that sticks to the skin, and the bag attaches to this. This enables the bag to be changed without removing the flange.

Some bags have a second opening at the bottom to allow emptying. These are most useful in the period immediately after operation and in patients who have had ileostomy, who need to drain their bag regularly. Closed bags are used when the faeces are well formed and are usually only changed once or twice a day. Most patients with a stoma will use an opaque bag, but in the period immediately after operation a transparent bag is used to observe the new stoma for complications such as persistent oedema or necrosis. Modern stoma bags are fitted with a carbon or charcoal flatus filter that allows gas to escape to prevent the bag from ballooning or detaching and neutralises odour.

Complications

Functional problems, such as skin excoriation and stoma noises, are the most common complications and are usually managed by the stoma nurse. Patients with stoma admitted to hospital with increased or decreased output should be appropriately managed to exclude any abdominal emergency, with particular emphasis on careful history taking to establish the normal bowel pattern, and attention to fluid balance.

Most structural problems, such as stoma prolapse, retraction, and parastomal hernia formation can be managed conservatively with modified bags and specialised belts. Only about 10% of patients with these complications will require further surgery.⁴ Patients should be alert to any change in colour of their stoma. Stomal oedema is normal for several days after surgery, but if the mucosa becomes dusky or necrotic the surgeon should be contacted promptly.

Stoma nurses

A stoma is more than just a surgical procedure; it has huge social and psychological implications that affect the patient’s daily routine, body image, and sex life. Stoma nurses are an essential part of the team and work closely with the surgeon, general practitioner, and community nurses. They are highly trained specialists who provide information and support for most of the physical and psychological problems that patients face on a day to day basis.

Clinical scenario

Examine this man’s abdomen (fig 7).

Fig 7 Clinical scenario patient

(1) What findings on abdominal examination would help determine the type of stoma used here?

(2) If the patient is 26 years old, what are the most likely pathologies to have necessitated an ileostomy?

(3) What complications may occur after stoma formation?

Answers

(1) See table 1.

(2) Severe Crohn’s disease, particularly with severe perineal involvement; severe ulcerative colitis; or traumatic large bowel injury with peritonitis, for example, a road traffic crash or knife injury.

(3) Possible early complications are stomal necrosis and high output causing dehydration. Possible late complications are stomal hernia, prolapse, and retraction.

1. Coloplast. An introduction to stoma care: a guide for healthcare professionals. Peterborough: Coloplast, 2004.
2. Nugent KP. Intestinal stomas. In: Johnson CD, Taylor I, eds. Recent advances in Surgery (22). London: Churchill Livingstone, 1999: 135-46.
3. Fazio VW, Wu JS. Surgical therapy for Crohn’s disease of the colon and rectum. Surg Clin North Am 1997;77:197-210.
4. Shellito M. Complications of abdominal stoma surgery. Diseases Colon Rectum 1998;41:1562-72.

       

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