Following a colorectal resection, under certain circumstances the transected end of the bowel is unable to be joined together or there may be clinical reasons for normal bowel motion across the anastomosis to be avoided, even with the bowel joined together. In these circumstances a stoma will be created, either permanently or temporarily depending on the condition.

A stoma connects the bowel to an opening on the abdomen, diverting faecal waste out of the body spontaneously. A stoma bag has to be fixed around the stoma to collect the faecal waste as it will flow out freely into a bag (which requires emptying several times each day).

Diverting stoma is usually temporary and is performed on patients with diverticular disease, inflammatory bowel disease, bowel cancer or bowel injury. When the distal part of the bowel has healed and regains normal bowel function, the stoma can be closed. If a tumour is located too close to the anus and has to be resected with anus and perianal tissue, the stoma will be permanent.

Different types of stoma include:

• Small bowel stoma – where part of the small bowel is used to form a stoma (known as an enterostomy, or ileostomy if the ileum is brought out)
• Large bowel stoma – where part of the large bowel or colon is used to form a stoma (known as a colostomy)