A segment of bowel that needs to be removed is one that has become necrotic and cannot be restored to function. Such a segment has no chance of regaining function even if the blood supply is restored, and if it is not removed it will instead become necrotic in the abdominal cavity, causing more serious complications such as peritonitis, infection and toxic shock.
In strangulated intestinal obstruction, if necrosis has already occurred or if necrosis of the intestinal segment still occurs after restoration of blood supply, partial resection of the intestine and reconstruction of the digestive tract with intestinal anastomosis is often required.
The second reason for removal of the bowel is the presence of intestinal conditions that require surgical management and which are often the cause of intestinal torsion, including: redundant colon, intestinal tumours etc.