STOMAS(Colostomy)

                  A colostomy is an artificial opening made in the large bowel to divert faeces and flatus to the exterior, where it can be collected in an external appliance. Depending on the purpose for which the diversion has been necessary, a colostomy may be temporary or permanent.

Figure:Colostomy bag

     SUMMRY

     Stomas

·         May be colostomy or ileostomy

·         May be temporary or permanent

·         Temporary or defunctioning stomas are usually fashioned as loop stomas

·         An ileostomy is spouted; a colostomy is flush

·         Ileostomy effluent is usually liquid whereas colostomy effluent is usually solid

·         Ileostomy patients are more likely to develop fluid and electrolyte problems

·         An ileostomy is usually sited in the right iliac fossa

·          A temporary colostomy may be transverse and sited in the right upper quadrant

·         End colostomy is usually sited in the left iliac fossa

·         All patients should be counselled by a stoma care nurse before operation

·         Complications include skin irritation, prolapse, retraction, necrosis, stenosis, parastromal hernia, bleeding and fistulation.

Temporary colostomy

                                        A transverse loop colostomy has in the past been most commonly used to de function an anaestomosis after an anterior resection. It is now less commonly employed as it is fraught with complications and is difficult to manage; a loop ileostomy is preferred.

    A loop left iliac fossa colostomy is still sometimes used to prevent faecal peritonitis developing following traumatic injury to rectum, to facilitate the operative treatment of a high fistula in ano and incontinence.

    A temporary loop colostomy is made bringing a loop of colon to the surface, where it is held in place by a plastic bridge passed through the mesentery. Once the abdomen has been closed, the colostomy is opened, and the edges of the colonic incision are sutured to the adjacent skin margin. When firm adhesion of the colostomy to the abdominal wall has taken place, the bridge can be removed after 7 days.

    Following the surgical cure or healing of the distal lesion for which the temporary stoma was constructed, the colostomy can be closed. It is usual to perform a contrast examination (distal lopogram) to check that there is no distal obstruction or continuing problem at the site of previous surgery. Colostomy closure is most easily and safely accomplished if the stoma is mature i.e. after the colostomy has been established for 2 months. Closure is usually performed by an intra peritoneal technique, which is associated fewer  closure breakdowns with faecal fistulae.

Double barrelled colostomy

                                                This colostomy was designed so that it could be closed by crushing the intervening spur by using an enterotome or a stapling device. It is rarely used now, but occasionally the colon is divided so that both ends can be brought to the surface separately, ensuring that the distal segment is completely defunctioned.

Permanent colostomy

                                      This is usually formed after excision of the rectum for a carcinoma by the abdomino-perineal technique. It is formed by bringing the distal end(end colostomy) of the divided colon to the surface in the left iliac fossa, where it is sutured in place, joining the margin to the surrounding skin. The point at which the colon is brought to the surface must be carefully selected to allow a colostomy bag to be applied without impinging on the bony prominence of the antero superior iliac spine. The best site is usually through the lateral edge of the rectus sheath, 6 cm above and medial to the bony prominence.

Complications of colostomies

                                                  The following complications can occur to any colostomy but are more common after poor technique or siting of the stoma:

• Prolapse
• Retraction;
• Necrosis of the distal end;
• Fistulae formation;
• Stenosis of the orifice
• Colostomy hernia
• Bleeding
• Colostomy diarrhoea; this is usually an infective enteritis and will respond to oral metronidazole 200 mg three times daily.

Many of these complications require revision of the colostomy.

Loop ileostomy

                           An ileostomy is now often used as an alternative to colostomy, particularly for defunctioning a low rectal anaestomosis. The advantages of a loop ileostomy over a loop colostomy are the ease with which the bowel can be brought to the surface and the absence of odour. Care is needed, when the ileostomy is closed, that the suture line obstruction does not occur.