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| ==Treatment== | | ==Treatment== |
| + | The term subtotal colectomy describes the removal of the majority |
| + | of the colon. There are two variations of the technique depending |
| + | on whether the ileocaecocolic valve is preserved or removed. This |
| + | structure prevents reflux of colonic contents into the small intestine; |
| + | therefore, some surgeons consider that removing the valve will predispose |
| + | to bacterial overgrowth in the small intestine, steatorrhoea |
| + | and deconjugation of bile salts. The rationale for excision of the |
| + | valve is that it minimises the recurrence of segmental megacolon |
| + | and associated constipation. For the surgeon, an added complication |
| + | is that differentiation between diseased and normal tissue |
| + | cannot be reliably made by gross |
| + | evaluation at surgery. |
| + | Removing the majority of the colon |
| + | will undoubtedly have certain metabolic |
| + | effects on the animal. The colon |
| + | normally acts to absorb water along |
| + | an osmotic gradient created by active |
| + | sodium absorption. Bicarbonate ions |
| + | are secreted in exchange for chloride |
| + | ions, and potassium is lost from extracellular |
| + | fluid; in addition, mucus and cells are shed into the colon. |
| + | Questions remain about water and electrolyte homeostasis, and |
| + | absorption of specific nutrients such as vitamin K following subtotal |
| + | colectomy. Enteric function following subtotal colectomy has been |
| + | evaluated in both normal and clinically affected cats and no significant |
| + | clinical or subclinical evidence of abnormal bowel function |
| + | was found (Gregory and others 1990). Histology of the small |
| + | intestinal wall following subtotal colectomy showed increases in |
| + | villus height, enterocyte height and density, with an increased |
| + | mucosal absorptive area. Serum cobalamin and faecal sodium |
| + | levels were higher in cats treated surgically, and faecal potassium |
| + | was low; however, the significance of these findings is unknown. |
| + | Tenesmus and loose faeces are often seen immediately postsurgery, |
| + | with faeces gradually progressing to soft but formed by |
| + | about three months; resection of the ileocaecocolic valve is, however, |
| + | associated with persistence of looser stools. |
| + | The issue of exactly how much of the colon to remove will remain |
| + | controversial until more information is published regarding longterm |
| + | outcome and function. However, the author’s preference in |
| + | the majority of cases is to resect the ileocaecocolic valve and perform |
| + | enterocolostomy. If the ileocaecocolic valve is to be preserved, |
| + | the colon is transected 3 cm from the caecum to ensure a |
| + | tension-free colocolostomy (the short mesocolon restricts mobility). |
| + | It is essential that there is no longitudinal tension on the anastomosis |
| + | site postoperatively, as this is likely to lead to dehiscence, with |
| + | potentially disastrous results. |
| + | If the valve is resected and an enterocolostomy performed, the |
| + | disparity in luminal widths can be dealt with by oblique incision of |
| + | the ileal portion combined with a short antimesenteric incision to |
| + | spatulate the intestine. A single layer of full-thickness appositional |
| + | sutures using polydioxanone in a simple interrupted pattern is the |
| + | author’s preference. An end-to-end or end-to-side anastomosis can |
| + | also be created using surgical stapling equipment. |
| + | It should be noted that older surgical procedures such as coloplasty |
| + | and partial colectomy provide little or no long-term improvement |
| + | and are not recommended. |
| + | Complications associated with subtotal colectomy |
| + | Operative complications are uncommon. Where reported, complications generally relate to the anastomotic procedure; for example, |
| + | technical errors leading to dehiscence, or localised peritonitis resulting from contamination at surgery. The most commonly reported |
| + | complication in the long term is recurrence of constipation. The majority of these individuals can be managed medically, but some cases |
| + | will require repeat surgery. |
| + | |
| ==Prognosis== | | ==Prognosis== |
| ==Links== | | ==Links== |