What is a stoma?
A stoma is a surgically created opening in the body between the skin and a hollow viscus (stoma has the Greek meaning ‘mouth). Abdominal stomas are mainly used to divert faeces or urine outside the body where it can be collected in a bag at the skin.
There are three common stoma types:
=> Colostomy
=> Ileostomy
=> Urostomy
Each stoma can be either permanent or temporary.
A stoma’s position, appearance and contents can indicate which type of stoma it is and provide clues as to the patient’s previous surgical history.
Colostomy
=> As the name suggests colostomies are made using the large bowel (or colon).
=> One of the hallmarks of colostomies is that they are found in the left iliac fossa (LIF).
=> The content of a colostomy bag should be solid as the faeces have had time to travel through the colon undergoing water absorption.
=> Colostomies are positioned flush to the skin (i.e. no spout) because the enzymes present in large bowel contents are less alkali and therefore less irritating to the skin.
Permanent end colostomy vs temporary end-colostomy
=> Permanent end colostomies are often done in cases of abdominoperineal resection of large rectal cancers leading to the removal of the entire rectum.
=> Temporary end colostomies are done to rest the bowel such as in the case of diverticulitis or obstruction. As part of a two-stage Hartmann’s procedure, the rectum and bowel will be re-anastomosed at a later date.
Loop colostomy
=> Loop colostomies are performed to protect distal anastomoses after recent surgery.
=> A loop of bowel will be brought to the surface and half-opened, this allows the faecal matter to drain into the stoma bag without reaching the distal anastomoses.
Ileostomy
=> Ileostomies are created using small bowel.
=> They are typically located in the right iliac fossa (RIF).
=> Less water is absorbed in the small bowel so the contents of the stoma bag tend to have a liquid consistency.
=> Because the enzymes contained in small bowel contents can irritate the skin, the bowel has a spout sticking out from the abdominal wall. This allows faeces to drain without touching the skin.
Temporary vs permanent end-ileostomy
=> Permanent ileostomies are typically created after a panproctocolectomy for ulcerative colitis or familial adenomatous polyposis.
=> A temporary end-ileostomy is typically created during emergency bowel resection where it is considered unsafe to form an anastomosis with the remaining bowel at that time (e.g. intra-abdominal sepsis or bleeding).
Loop ileostomy
=> Temporary loop ileostomies are created in the same way that temporary loop colostomies are, with two openings being visible.
=> They are used to protect distal anastomoses.
Urostomies
=> Urostomies after created after a cystectomy (bladder removal).
=> They are typically located in the right iliac fossa (RIF).
=> The bag will contain urine.
=> An ileal conduit is used to route the urine out of the abdomen into the bag. This involves a piece of ileum being resected then attached to the skin with a spout protruding.
=> The ureters are then attached to the other end of the bowel.
=> The urine then drains via the piece of bowel into the stoma bag.