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Sub-total colectomy can be used to correct megacolon in the cat. However, this technique is very poorly tolerated in the dog. The term refers to the removal of the majority of the colon, and the ileocaecocolic valve may be preserved or removed. The ileocaecocolic valve prevents reflux of colonic contents into the small intestine and so some surgeons believe that removing this structure can predispose to small intestinal bacterial overgrowth,steatorrhoea and deconjugation of bile salts<sup>2</sup>. However, removing the ileocaecocolic valve minimises the recurrence of megacolon.
Sub-total colectomy can be used to correct megacolon in the cat. However, this technique is very poorly tolerated in the dog. The term refers to the removal of the majority of the colon, and the ileocaecocolic valve may be preserved or removed. The ileocaecocolic valve prevents reflux of colonic contents into the small intestine and so some surgeons believe that removing this structure can predispose to small intestinal bacterial overgrowth,steatorrhoea and deconjugation of bile salts<sup>2</sup>. However, removing the ileocaecocolic valve minimises the recurrence of megacolon.
The issue of exactly how much of the colon to remove will remain
The issue of exactly how much of the colon to remove will remain
controversial until more information is published regarding longterm
controversial until more information is published regarding longterm
and partial colectomy provide little or no long-term improvement
and partial colectomy provide little or no long-term improvement
and are not recommended.
and are not recommended.
Although sub-total colectomy is an effective way of correcting megacolon, removal of majority of the colon has the potential to cause metabolic effects in the animal. For example, the colon normally functions to absorb water. This is achieved by the creation of an osmotic gradient by active sodium absorbtion. Additionally, extracellular potassium is lost and bicarbonate ions are exchanged for chloride ions in the colon. It could therefore be implied that sub-total colectomy disrupts water and electrolyte homeostasis, but paradoxically cats undergoing sub-total colectomy have been found to show no clinical evidence of abnormal bowel function<sup>6</sup>. However, other, non-clinical changes were found: small intestinal enterocytes and villi were increased in height, the absorptive area of the small intestinal muscosa was increased, serum cobalamin and faecal sodium were increased and faecal potassium was low. The significance of these results is unknown.
After surgery faeces are loose and defaecation is associated with tenesemus, but faecal consistency improved over the following months. Complications associated with the surgery itself are rare and tend to related to the anastomotic procedure<sup>2</sup>. For example, the abdomen may become contaminated during surgery, leading to peritonitis, or the anastomosis site may break down.
Complications associated with subtotal colectomy
Complications associated with subtotal colectomy
Operative complications are uncommon. Where reported, complications generally relate to the anastomotic procedure; for example,
Operative complications are uncommon. Where reported, complications generally relate to the anastomotic procedure; for example,