Stomas

Question 1

Indications and general principles (1)

Answer 1

• often necessary to divert the faecal stream to the anterior abdominal wall via a stoma
• The effluent is collected in a removable plastic bag attached by adhesive to the abdominal skin
• Stomas are named according to the part of the bowel opening on to the abdominal wall, i.e. ileostomy or colostomy
• urostomy is used for the ileal conduit that connects ureters to the skin surface in patients whose bladder has been removed.

Question 2

Indications and general principles (2)

Answer 2

• Stomas may be permanent or temporary
• Permanent stomas
  necessary when there is no distal bowel segment remaining after resection or when bowel is not to be rejoined.
• A colostomy is required after abdomino-perineal excision of a low rectal or anal canal tumour.
• ileostomy is employed after excision of the whole colon and rectum (pan-proctocolectomy) unless a pouch reconstruction is performed
• Defunctioning stomas
  A ‘defunctioning’ stoma (ileostomy or colostomy) used to protect a distal anastomosis at risk of leakage or breakdown by preventing intraluminal pressure rises and diverting the faecal stream
• Bowel rest
  A temporary colostomy may be used to ‘rest’ a more distal segment of bowel or a perineum involved in an inflammatory process

Question 3

Types of stoma(1)

Answer 3

• The way in which a stoma is fashioned depends on its purpose.
• Colonic stomas are designed with the bowel mucosa lying almost flush with the skin.
• Small bowel stomas are fashioned with a ‘spout’ of bowel protruding about 3 cm, to ensure that the irritant small bowel contents enter the ileostomy appliance directly rather than flowing on to the skin

Question 4

Types of stoma (2)

Loop Stoma

Answer 4

• This type of stoma is designed so that both proximal and distal segments of bowel drain onto the skin surface.
• This deflects proximal effluent to the skin surface and provides a ‘blow-off’ valve for the distal loop.
• Loop stomas are used mainly for temporary defunctioning to protect a distal anastomosis.
• It is straightforward to reanastomose the ends at reversal; the loop is then dropped back into the abdomen.
• The most common form of loop stoma is the loop ileostomy; occasionally a loop transverse colostomy is used.

Question 5

Types of stoma (3)

Split or ‘spectacle’ stoma

Answer 5

• This is the ultimate form of defunctioning stoma but has been largely superseded by the loop stoma.
• After resection, both proximal and distal bowel ends are brought separately to the skin surface.
• The proximal end stoma passes stool into a stoma appliance; the distal stoma (or mucous fistula) defunctions the bowel beyond it and produces just a little mucus.

Question 6

Types of stoma (4)

End Stoma

Hartmann’s procedure: end colostomy and rectal stump

Answer 6

• This type of stoma is usually permanent. An end colostomy is most commonly used to ‘resite the anus’ on to the abdominal wall after removal of the rectum and anal sphincter
• An ileostomy may be employed after subtotal or pan-proctocolectomy, particularly in fulminant colitis.
• Hartmann’s procedure is a relatively safe technique, particularly for less experienced surgeons, and carries less overall risk than primary anastomosis.

Question 7

Complications of colostomy and ileostomy

Answer 7

Early complications:

• Mucosal sloughing or necrosis of the terminal bowel due to ischaemia - Reoperation and refashioning of the stoma
• Obstruction of stoma due to oedema or faecal impaction - Exploration with a gloved finger and sometimes glycerol suppositories or softening enemas
• Persistent leakage between skin and appliance causing skin erosion and patient distress, often due to inappropriate location of stoma (e.g. over skin crease) -May respond to stoma nursing care or require a resiting operation

Late Complications:

• Parastomal hernia due to abdominal wall weakness - Resiting of stoma +/− mesh reinforcement of abdominal wall
• Prolapse of bowel - Refashioning of stoma
• Parastomal fistula - Refashioning of stoma, or local repair, possibly laparoscopic
• Retraction of ‘spout’ ileostomy - Reoperation and refashioning of a new ileostomy
• Stenosis of stomal orifice - Refashioning of stoma
• Perforation after colonic irrigation - Emergency operation
• Psychological and psychosexual dysfunction - May require counselling or measures to reverse stoma