Although the need for permanent stomas has reduced in recent years with technical advances in restorative rectal surgery and sphincter salvage, the abdominal stoma still serves a critical function in the management of benign and malignant gastrointestinal problems. Although the quality of life of most ostomates is nearnormal, there are physical and psychosocial limitations as a result of the stoma. The judicious assessment of the need for the stoma, careful surgical technique and skilled enterostomal nursing are essential for a satisfactory outcome. The management of patients with a stoma must begin before the operation, and the key to management of surgical complications is prevention. The main types of intestinal stoma are:
- ileostomy: end, loop, loop-end
- colostomy: end, loop
An end ileostomy is formed usually from the end of the terminal ileum (Construction of an end ileostomy). Formerly, a permanent ileostomy was made after a proctocolectomy for inflammatory bowel disease or familial polyposis.With the advent of newer sphincter-saving procedures, such as a restorative proctocolectomy, this is now less commonly performed. The ileostomy can be temporary and is potentially reversible when it has been done in conjunction with subtotal abdominal colectomy for toxic colitis, left-sided large bowel obstruction or ischaemic bowel. In the latter situation, diversion is established when the hazards of primary anastomosis between the ileum and the colon or rectum are considered to be unacceptably high, because of bowel ischaemia, severe sepsis or gross nutritional depletion.
The terminal ileum is drawn through an elliptical incision in the right lower quadrant and through a muscle-splitting incision in the rectus muscle. A fullthickness eversion of the bowel is then performed to obtain primary Brooke-type maturation between the distal edge of the ileum and the dermis of the skin (Eversion and maturation of an end ileostomy.).
The principles of construction of an ileostomy are given in The principles of construction of an ileostomy.
This is used temporarily to protect a distal anastomosis such as an ileal pouch-anal anastomosis or a low colorectal anastomosis, or to divert stool from the distal anorectum such as for perianal Crohn's disease, fungating anorectal cancer, severe perineal trauma or sepsis and faecal incontinence. It is formed using a loop of the distal ileum delivered through the abdominal wall, usually in the right lower quadrant as for end ileostomy (Construction of a loop ileostomy.). A supporting rod is usually inserted through the mesentery under the apex of the ileal loop to relieve tension on the loop ileostomy. An incision is then made just above the skin level on the efferent (defunctioned) loop of ileum. The afferent (functional end) is then everted to form the larger of the two stomas (Loop ileostomy.). The afferent limb produces the stool output and the efferent limb allows passage of flatus and mucous discharge from the distal defunctioned portion of the bowel. Subsequent take-down and closure of a loop ileostomy can usually be done through a parastomal incision and generally does not involve a formal laparotomy. If done successfully, recovery is rapid and the duration of hospitalisation averages 4–5 days.
The loop-end ileostomy is an alternative to a temporary loop ileostomy when the loop of ileum cannot be delivered beyond the stoma aperture without excessive tension. This ileostomy is matured as a conventional loop ileostomy.
The stoma is oedematous immediately postoperatively, but this resolves within a week or so. The normal colour of the mucosa ranges from pink to deep red. The viability of the stoma is examined periodically in the post-operative period.
Intestinal peristalsis usually recommences 2–5 days after surgery. Sometimes there is an early output of watery intestinal content (bowel sweat) before return of bowel function. Oral feeding should be deferred until the paralytic ileus is resolved. Occasionally, the supporting rod of a loop ileostomy causes partial obstruction at the fascial level. The rod is usually removed after 4–5 days when sufficient adhesion has formed between the loop of bowel and the stoma aperture to prevent retraction of the stoma. The normal ileostomy output ranges between 500 and 1000 mL. Higher outputs may result in dehydration. Low output may indicate an obstruction. A partial bowel obstruction may, paradoxically, be associated with a high output of watery intestinal content.
Education on stoma care commences pre-operatively and continues post-operatively. As oedema subsides, the stoma is remeasured for new appliances about 4 weeks after construction. A properly fitting stoma appliance is important to avoid leakage of small bowel content, with resultant skin excoriation.
About 50% of patients experience some dietary restrictions post-operatively. Initially, a low-residue diet is recommended but within a few weeks other foods may be introduced. Foods that commonly affect ostomates are nuts, popcorn, corn, string vegetables, cabbage, oranges or fruit peels.
With a well constructed stoma and good stoma education, most ostomates achieve a good quality of life and the majority enjoy a normal life or experience only minor restrictions.
Complications after the creation of an ileostomy may be due to technical error, recurrent disease or poor stoma care (Common complications of ileostomy). Overall about 30% of patients experience a stoma-related complication.
About 20% of patients require revisional surgery to the ileostomy; such revisional surgery is more frequent in patients with Crohn's disease because of recurrence of disease. With recurrent Crohn's disease, treatment is directed towards the Crohn's disease itself. It may entail a laparotomy, resection of the diseased stoma and the adjacent segment of ileum, and formation of a neo-ileostomy at the same or another site. Other common indications for revisional surgery are retraction or prolapse of the stoma, and stricture and fistula formation. Some patients may require resiting of the stoma because of problems related to leakage. Unlike the situation with colostomies, parastomal hernia formation is infrequent.
End sigmoid colostomy
This may be temporary or permanent. The end stoma is permanent following abdominoperineal resection of the rectum for malignant disease or for severe faecal incontinence not appropriate for a perineal repair. It may serve as a temporary stoma for faecal diversion in radiation proctitis or following a Hartmann's procedure for resection of the rectosigmoid with benign or malignant disease. Because of the absorptive capacity of the proximal colon, the colostomy effluent is usually solid and non-irritating. Thus, the colostomy can be made flush with the skin without a spout.
Loop colostomy may be constructed using a loop of the transverse or sigmoid colon. It serves as a temporary faecal diversion following a low colorectal anastomosis or for obstruction, inflammation, trauma or perineal wounds. The loop colostomy may be constructed over a supporting rod through the mesocolic window, analogous to a loop ileostomy. An incision is made across the apex of the colon and both the afferent and efferent limbs of the bowel are sutured to the skin. Depending on the mobility of the colon and the body habitus of the patient, the loop of colon may be brought through either the lower quadrant or the right upper quadrant. While most loop colostomies are fully diverting in the first few months after construction, faecal diversion becomes incomplete in about 20% of patients subsequently because of recession of the stoma.
A tube caecostomy using a No. 30 Fr Foley catheter is usually performed rather than a primary stoma. It is done for either colonic decompression or caecal volvulus. The tube can be removed after 7–10 days and the caecocutaneous fistula should close spontaneously in the absence of a distal obstruction. However, a caecostomy is not fully diverting and is difficult to manage because of dislodgement or blockage of the tube. This procedure is now rarely performed.
The early management of a colostomy is similar to that for an ileostomy. Pre-operative stoma siting and counselling are as important. These patients tend to have concerns different from those of ileostomates, because they are often elderly and the diagnosis is usually cancer.
Following abdominal surgery, there is an ileus for the first 2–3 days. In contrast to ileostomy, where oral feeding is often delayed until the ileostomy has passed gas and effluent, the colostomy often requires stimulation by ingestion of food before it begins to function. Ischaemia tends to occur more with a colostomy than with an ileostomy because of the poorer vascular supply of the colon.
Function through a descending colostomy is similar to normal bowel function and may be susceptible to constipation. Bulking agents may help regulate the stoma. Some patients with an end colostomy may wish to try daily colostomy irrigations with lukewarm water. While the irrigation procedure takes 1–2 hours and the patient has to be motivated, there will be no soiling of stool throughout the rest of the day and a cap may be worn.
Complications associated with a colostomy are similar to those with an ileostomy (see Common complications of ileostomy), but they differ in frequency. Parastomal hernia (Paracolostomy hernia with a colostomy stricture.) and stoma prolapse are common because of the larger stomal aperture, especially with a loop stoma. Stricture also occurs more frequently because of the more tenuous blood supply. Food bolus obstruction and skin irritation are less common than that found in ileostomates.