Intestinal Stomas

Protection of distal anastomosis

Treatment of anastomotic leak

Large bowel obstruction

Bowel perforation

Abdominal or perineal trauma

Rectal injury

Diverticular disease

Complex anorectal disease

Complications from radiation

Fecal incontinence

Inflammatory bowel disease

Motility and functional disorders including idiopathic megarectum and megacolon

Infections – necrotizing fasciitis, Fournier’s gangrene

Congenital disorders – imperforate anus, Hirschsprung’s disease, necrotizing enterocolitis, intestinal atresias

Permanent stomas are indicated for:

Removal of the anus along with its associated musculature.
Distal rectal cancers which require an abdominoperineal resection.
Severe inflammatory bowel disease with involvement of the sphincter mechanism.
Patients of any age with weak sphincter muscles and/or fecal incontinence may be better served with permanent fecal diversion in order to prevent perineal skin breakdown, improve perineal hygiene, and prevent decubitus ulcer formation.

Temporary stomas are indicated for:

Diffuse peritonitis from a perforated colon due to inflammatory conditions
Patients who undergo a high-risk distal bowel anastomosis (e.g., following neoadjuvant radiation)
Patients who may be symptomatic enough that fecal diversion should be considered as the initial management for their rectal cancer

Ileostomy vs. Colostomy

Ileostomy may be preferable because of ease of reversal, easier stoma management, and lower incidence of parastomal hernia and sepsis and more effective in diverting the fecal stream.
Loop colostomies have more complications such as parastomal and incisional hernias, stomal prolapse, and fecal fistulas.

Stomas may be created as either a loop stoma or an end stoma.
Loop stomas are often used when they are temporary and in the presence of a distal intestinal obstruction, whereby the primary cause of the obstruction is left undisturbed.
Loop stomas are often larger than end stomas since both limbs of bowel must be exteriorized through the same fascial defect.
Loop stomas may be more prone to develop parastomal hernias.
End stomas are often smaller and easier to manage. They are rarely associated with stomal prolapse and may have a lower incidence of parastomal hernia formation.
End stomas often require more extensive surgery for reversal.
Another alternative in stoma creation is the loop end stoma. This may be performed in the obese patient.

The physiological changes that occur are primarily related to the loss of continence and reduced colonic absorptive surface area. These affect fluid and electrolyte balance.
However, once more than 50 cm of terminal ileum has been removed or taken out of continuity, nutritional consequences are likely.
Distal left or sigmoid colostomies normally produce formed stools.
Right-sided colostomies not only produce a high volume but also have the additional disadvantage of a malodorous output because of the effects of colonic bacteria.
Initially after creation, the output from an ileostomy tends to be fairly watery and green or bilious in color.
It is affected by diet, fluid intake, medications, and ongoing problems such as Crohn’s disease or adhesions.
If a substantial amount of small bowel has been removed, the output is looser and the patient is more prone to dehydration.
Most patients with an ileostomy notice little odor from the output; however, certain foods, such as eggs and fish, may produce an offensive smell.

In the healthy control subject, about 1,000–2,000 ml of fluid passes through the ileocecal valve daily.
This quantity is reduced by 80–90 % to 100–200 ml of fluid volume in normal stool as it passes through the colon.
The average colostomy produces about 200–700 ml with a median of about 500 ml per day. Total bowel rest results in a decrease in output by at least one-half and may be as low as 50–100 ml per day.
Although the average output is about 500 ml per day, a healthy, functioning ileostomy may produce up to 1,000–1,500 ml in a day. Output above this level is usually associated with dehydration.
Ileostomy effluent is generally weakly acidic at a pH of about 6.3.

It appears that small bowel transit times decrease after ileostomy, possibly related to mucosal hypertrophy and adaptation. The specific mechanisms are not known.
Gastric emptying is not altered in ileostomy patients. Yet, small bowel transit is longer than in control subjects (348 vs. 243 min).

The average ileostomy puts out about 500 ml of water and 60 mmol of sodium per day and amounts approximately two to three times higher volumes than found in normal fecal output.
Urinary volume is relatively decreased in patients with ileostomies by as much as 40 %, while renal sodium losses may be decreased by 55 %.
Total body water and sodium reductions may be a chronic condition in ileostomy patients.

The normal terminal ileum harbors few organisms in the healthy individual.
After creation of an ileostomy, the distal ileum is rapidly colonized with a variety of bacteria.
Staphylococci, streptococci, and fungi are increased, while Bacteroides fragilis is rarely found in ileostomy effluent.