This retrospective case series examines the outcome of 11 dogs that had transanal rectal pull-through amputation of a single colorectal adenocarcinoma or in situ carcinoma. The amputation was performed via a simple pull-through technique, or a combined abdominal-transanal pull-through technique. The simple pull-through technique began with a transanal approach, in which the rectal wall was everted through the anus and then mobilized after transection and blunt dissection of the associated structures along the external rectal surface. The mobilized rectum was retracted and resected to afford 2- to 6-cm cranial and caudal tumor margins. The normal cranial region was then anastomosed to the distal rectal stump. The combined abdominal transanal approach was used in 4 of the dogs when the tumor was located in the mid-to-cranial third of the rectum and extended into the descending colon. Caudal celiotomy was performed, lymph nodes were resected if indicated, and the colon was isolated by double ligation of the associated vasa recta. Each stump was oversewn and then loosely connected with 4 sutures. The wound was closed, the patient put into sternal recumbency, and the transanal rectal pull-through was performed as previously described. After excision of the distal colorectal stump containing the tumor, the oversewn suture was removed and then the cranial stump was anastomosed to the remaining distal rectum. Postoperative complications included rectal bleeding and tenesmus, which resolved spontaneously within 2 weeks to 2 months. Two dogs treated by the combined approach died in the immediate postoperative period. All but 1 tumor in this study were completely excised, and fecal continence was maintained overall because a minimum of 1 to 1.5 cm of distal rectum was preserved in the surgical technique. Local recurrence rate was 18.2%, and postoperative metastatic rate was 0%. Survival time ranged from 0 to 72 months. None of the patients was euthanized due to postoperative complications.
COMMENTARY: This is a fascinating article that describes an almost inconceivable surgical technique in which the distal colon is actually pulled completely outside the body of the patient, cut apart, and sewn back together. In one dog, the tumor was so large that it obstructed endoscopic view of the rectum. Although it may seem like a radical approach, this technique actually provided good quality of life for most of the patients for a significant time. An alternative to the combined approach for removing tumors in the cranial portion of the rectum would be a pubic symphyseal separation or osteotomy; however, this approach provides limited access and is fraught with complications. Although tenesmus and rectal bleeding were reportedly more common in this study than in previous literature, this method may be feasible for the appropriate case and when a well-trained surgeon is available.
Transanal pull-through rectal amputation for treatment of colorectal carcinoma in 11 dogs. Morello E, Martano M, Squassino C, et al. VET SURG 37:420-426, 2008.