A stoma is a surgically created opening of the bowel or urinary tract to a body surface. This picture shows a loop colostomy (i.e. it has both an afferent and efferent limb). It was a defunctioning sigmoid loop colostomy created above a locally advanced rectal carcinoma. Loop colostomies are usually fashioned from either the transverse or sigmoid colon. Loop ileostomies are fashioned from the distal ileum. Both loop colostomies and ileostomies are created to protect anastomoses or divert bowel content from disease segments of bowel (e.g. tumours or perianal fistulae). Soon after formation loop colostomies can often be recognised by the fact that they have a stoma bridge which is removed at about 10 days post-operatively. They are potentially reversible. Because of the bulk of this type of stoma they can occasionally be difficult to manage.

The other main type of stoma is an end colostomy or ileostomy. End colostomies are usually site in the left iliac fossa. For low rectal cancers they are created as part of an abdomino-perineal resection. In a Hartmann's procedure the sigmoid colon is resected, the rectal stump is oversewn and a left iliac end colostomy fashioned. The distal end of the divided bowel can often be brought to the surface, usually within the lower part of a midline abdominal wound, as a mucus fistula. End ileostomies are usually fashioned in the right iliac fossa often as part of a panproctocolectomy for inflammatory bowel disease. The typical Brooke ileostomy is fashioned with a spout to divert the small bowel content in to the stoma appliance. Unlike faeces, small bowel contents produce a painful skin burn if allowed to come into contact with skin. Other types of stoma include:

• Caecostomies - often created by intubating the caecum with Foley catheter.
• Urostomies - to divert urine
• Jejunostomies - often used to feed patients who have a function gut but who are unable to take food orally.

The requirement for a stoma is often devastating news to a patient. It will be even more of a burden if it is poorly sited or constructed. Stoma sites should be marked preoperatively. They should be on flat skin, away from scars and avoiding bony prominences and the umbilicus. The positioning of the patients clothing should also be taken into account.

Complications of stomas include:

• Functional disorders - diarrhoea & constipation
• Necrosis - usually seen within hours of surgery if it has been fashioned under tension and the blood supply compromised. Many stomas are swollen, discolou+0red and engorged soon after fashioning. This does not usually imply that the blood supply is compromised and things usually improve with time.
• Prolapse - alarming and unsightly. Often requires revision of the stoma.
• Stenosis - often requires revision of the stoma
• Parastomal hernia

Recent papers

Chen F.  Stuart M.  The morbidity of defunctioning stomata.  Aust N Z J Surg 1996;  66:  218-221.

Martin L.  Foster G.  Parastomal hernias.  Ann R Coll Surg 1996; 78:  81 - 84.

Nugent K P.  Intestinal stomas.  In:  Johnson C D,  Taylor I eds.  Recent advances in Surgery 22.  Churchill Livingstone 1999;  135-146.

Shellito M.  Complications of abdominal stoma surgery.  Dis Colon Rectum 1998;  41:  1562-1572.