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.
Temporary
colostomy
This is most commonly established to defunction an anastomosis after
an anterior resection, to prevent faecal peritonitis developing following
traumatic injury to the rectum or colon, and to facilitate the operative
treatment of a high fistula in ano. It is now less commonly used for
patients with distal obstruction of the sigmoid colon as a result of carcinoma
or diverticular disease.
A
temporary colostomy is made bringing a loop of colon to the surface (loop
colostomy) 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 (Fig.
57.52). When firm adhesion of the colostomy to the abdominal wall has taken
place, after 7 days the bridge can be removed.
A
loop of colon can most easily be brought to the surface using large bowel that
has a mesentery. Most loop colostomies are made in the transverse colon but the
sigmoid colon can also be suitable. 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 loopogram)
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, that is, after the colostomy has been established for 2
months. Closure is usually performed by an intraperitoneal technique which is
accompanied by fewer closure breakdowns with faecal fistulae.
Double-barrelled
colostomy
This colostomy was designed so that it could be closed by crushing the
intervening ‘spur’ 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
separately to the surface ensuring that the distal segment is completely
defuntioned.
Permanent
colostomy
This is usually formed after excision of the rectum for a carcinoma by
the abdominoperineal 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
colonic 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 anterosuperior iliac spine. The best site is usually through the lateral
edge of the rectus sheath, 6 cm above and medial to the bony prominence (Fig.
57.53).
An
important point after the colostomy has been made is to close the lateral space
between the intraperitoneal segment of the sigmoid colon and the peritoneum of
the pelvic wall, to prevent internal herniation of strangulation of loops of
small bowel through the deficiency. Alternatively a retroperitoneal tunnel for
the colostomy avoids creating lateral space.
Colostomy
bags and appliances (Fig. 57.54)
Faeces from a permanent colostomy ate collected in disposable adhesive
bags. A wide range of such bags is currently available. Many now incorporate a
stomahesive backing, which can be left in place for several days. In most
hospitals a stoma care service is available to offer advice to patients and to
acquaint them with the latest appliances, and the appropriate psychological and
practical help.
Complications of
colostomies
The following
complications can occur to any colostomy but are more common after poor
technique:
•
prolapse;
•
retraction;
•
necrosis of the distal end;
•
stenosis of the orifice;
•
colostomy hernia;
•
bleeding (usually from granulomas around the margin of the colostomy);
•
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. Sometimes this can be
achieved with an incision immediately around the stoma but on occasion reopening
the abdomen and freeing up the colostomy may be necessary. Occasionally transfer
to the opposite side of the abdomen may be necessary.
Loop
ileostomy
An ileostomy is used by some surgeons as an alternative to colostomy,
particularly for defunctioning a low rectal anastomosis. The creation of a loop
ileostomy from a knuckle of terminal ileum has already been described. 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 suture line obstruction does not occur.
Caecostomy
This is rarely used now. In desperately ill patients with advanced
obstruction, a caecostomy may be useful. In late cases of obstruction the caecum
may become so distended and ischaemic that rupture of