Colonic Volvulus in Dogs: How to fix it and prevent it from recurring.

Case Report

Addy is an 8-year-old female spayed Great Dane (Fig. 1) who presented to the MedVet Toledo emergency service for vomiting and diarrhea after eating garbage 3 days previously.  Six months previously Addy had a prophylactic gastropexy for prevention of gastric dilatation/volvulus and splenectomy to remove a benign splenic tumor.

Fig. 1: Addy, an 8 year old female spayed Great Dane with colonic volvulus.

On physical examination Addy was quiet but alert, responsive and ambulatory. Her vital signs were normal. She was approximately 5% dehydrated and was painful on abdominal palpation. Blood samples were submitted for CBC and serum chemistry profile, which were within normal limits. 

Plain film abdominal radiographs were obtained. Severe gaseous dilation of the proximal large bowel was identified, and mal-positioning of the descending colon was suspected. (Fig. 2) Based on the clinical signs and radiographic findings, a tentative diagnosis of colonic torsion was made. 

Fig 2a: Lateral radiograph of Addy showing severe dilation of the large
bowel in the cranial abdomen.

Fig. 2b: Ventrodorsal radiograph of Addy also showing severe dilation
of the large bowel in the cranial abdomen.

Emergency surgical exploration of the abdomen was recommended to the owners. Addy was placed under general anesthesia and prepared for a ventral midline abdominal exploratory. At surgery, severe dilation and malposition of the ascending colon, transverse colon, and proximal descending colon were found. (Fig. 3) The ascending colon and cecum were located on the left side of the abdomen, and the proximal descending colon located on the right side of the abdomen. Therefore a 180-degree volvulus of the proximal colon on its mesenteric axis had occurred. Although severely dilated, the colonic tissues were only mildly congested and appeared viable with no areas of necrosis.

Fig. 3: Intraoperative photo of Addy in dorsal recumbency, head is to the left.
The descending colon (DC) is malpositioned to the right side of the abdomen,
and the ascending colon (AC) is malpositioned to the left, creating a volvulus
of the transverse colon (AC).

The abnormally positioned colonic segments were replaced back to their normal positions, i.e., cecum and ascending colon back to the right side of the abdomen, and descending colon to the left side. To prevent future episodes of volvulus, a gastrocolopexy and left sided abdominal colopexy between the descending colon and interior abdominal wall were performed. The gastrocolopexy was performed by apposing the transverse colon to the greater curvature of the stomach. The serosal surfaces of the stomach and colon were scarified, and a simple continuous suture of 2-0 PDS was used to approximate the 2 structures. (Fig. 4) 

Fig. 4: Intraoperative photo of Addy after creating the gastrocolopexy (arrows)
between the transverse colon (TC) and the greater curvature of the stomach (S).

The abdominal colopexy was performed by first making a 10 cm cranial to caudal incision in the interior abdominal wall musculature. The descending colon was then scarified and placed adjacent to the abdominal incision. The dorsal edge of the abdominal incision was sutured to the seromuscular layer of the descending colon with 2-0 PDS in a simple continuous pattern, then the ventral edge of the abdominal incision was also sutured to the descending colon in a similar fashion. (Fig. 5) 

Fig. 5: Intraoperative photo of Addy after creating the colopexy (arrows)
between the descending colon (DC) and the abdominal wall (A).

The remainder of the abdomen was explored and no other abnormalities were discovered. The previously performed gastropexy between the pyloric antrum and the right interior abdominal wall appeared to be competent. 

The abdominal incision was closed routinely and Addy was recovered from anesthesia.  Addy did well postoperatively and was discharged from the hospital with analgesic medications and instructions to feed a bland diet for the next several days.  Two weeks postoperatively Addy was doing well with a good appetite and normal stools. 

Discussion
Colonic volvulus is a rarely reported disorder in dogs that is characterized by acute displacement of one or more segments of the large intestine. The disorder is also referred to as colonic torsion. However, on based previous clinical studies and the author’s clinical experience volvulus is a more accurate term to describe the condition since the transverse colon becomes twisted on its mesenteric axis. (1,2)

Although not confirmed statistically, large breed dogs appear to be more susceptible to colonic volvulus. Combining cases found in 3 retrospective studies, 30/31 of the reported dogs were large breeds. (1-3) One study also found a high incidence of previously performed gastropexy in dogs with colonic volvulus. However, this also has not been statistically proven and large breed dogs will be more likely to have had a gastropexy so the association could be coincidental. 

Clinical signs of affected dogs are acute vomiting, anorexia, and discomfort. Radiographically there is dilation of the affected colon, abnormal positioning of the large bowel, particularly the descending colon and cecum, and focal narrowing of the colon. (Ref)

The treatment of choice for colonic volvulus is immediate surgical intervention to replace the affected segments of the colon to their normal position and perform colopexy procedures to prevent recurrence of the volvulus. The gastrocolopexy is intended to stabilize the transverse and ascending colon and cecum to prevent them from flipping from right to left, and the standard descending colon colopexy to the abdominal wall prevents the descending colon from moving left to right.(For a detailed description of abdominal colopexy see: https://drstephenbirchard.blogspot.com/2019/03/how-to-perform-colopexy-in-dogs-and-cats.html.) The limited clinical reports of colonic volvulus indicate that this surgical approach is effective which is consistent with the author’s experience. 

References

1. Bentley AM1, O'Toole TE, Kowaleski MP, Casale SA, McCarthy RJ Volvulus of the colon in four dogs. J Am Vet Med Assoc. 2005 Jul 15;227(2):253-6, 236-7. 
2. Plavec T, Rupp S, Kessler M. Colonic or ileocecocolic volvulus in 13 dogs (2005-2016). Vet Surg. 2017 Aug;46(6):851-859. 
3. Gremillion CL, Savage M, Cohen EB Radiographic findings and clinical factors in dogs with surgically confirmed or presumed colonic torsion. Vet Radiol Ultrasound. 2018 May;59(3):272-278.





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How to Perform a Colopexy in Dogs and Cats

How to Perform A Colopexy in Dogs and Cats

Colopexy is a surgical procedure in dogs and cats intended to produce a permanent adhesion between the descending colon and the interior of the left abdominal wall. The procedure is indicated in animals with conditions such as rectal prolapse that is not responsive to other treatment methods, in selected cases of perineal hernia with rectal sacculation, and in dogs with colonic volvulus. In rectal prolapse the colopexy prevents recurrence of the prolapse since the colon is fixed to the body wall, preventing the rectum from prolapsing through the anus. In some dogs with severe rectal sacculation secondary to perineal hernia, primary herniorrhaphy may not sufficiently ameliorate the rectal pathology. Colopexy in these dogs can help straighten the rectum, reduce the size of the sacculation, and improve rectal function. Finally, colopexy can be used to prevent recurrence of colonic volvulus. Since the proximal portion of the descending colon becomes displaced to the right side of the abdominal cavity in colonic volvulus, colopexy of the descending colon to the left abdominal wall prevents that displacement and therefore prevents recurrence of the volvulus.

Surgical Technique

In the following series of step by step figures using a surgical model, colopexy of the descending colon to the interior of the left abdominal wall is demonstrated. After placing the animal under general anesthesia, the ventral abdomen is clipped and prepared for aseptic surgery. A ventral midline abdominal approach is performed. After a complete abdominal exploratory is performed, the descending colon is identified and placed adjacent to the interior of the abdominal wall at the proposed site of the pexy.

Place towel clamps on the left side of the linea alba incision and retract dorsally to better expose the interior of the abdominal wall. Make a 6-10cm (depending on the size of the animal) in the peritoneum and transversus abdominus muscle from cranial to caudal. (Fig. 1) 

Fig. 1: Make the initial incision in the abdominal wall through the peritoneum
and transversus abdominus muscle from cranial to caudal. (Cr-cranial, Ca-caudal)

The anti-mesenteric aspect of the descending colon is scarified with a scalpel to encourage a better adhesion to the abdominal wall. An incision is not made in the seromuscular layer of the colon to avoid accidental perforation of the colonic lumen.

Place the colon near the abdominal wall incision. Using gentle traction of the colon in a cranial direction, determine the optimal location of the colon on the abdominal wall to accomplish the desired goal. Suture the dorsal side of the abdominal wall incision to the seromuscular aspect of the colon in a simple continuous pattern with 2-0 PDS. (Fig. 2, 3)

Fig. 2: Suture the dorsal aspect of the abdominal wall(A) incision to the
descending colon. (DC) Note that needle direction is always from abdomen
to the colon. 

Fig. 3: Completed closure of dorsal abdominal incision to the colon.

Suture the ventral aspect of the abdominal wall incision to the colon is a similar fashion to complete the colopexy. (Fig. 4, 5)

Fig. 4: Beginning the closure of the ventral abdominal incision to the colon.

Fig. 5: Completed closure of the ventral abdominal incision to the colon. 

Postoperative Care

The abdominal incision is closed routinely and the animal is recovered from anesthesia. Supportive care consisting of intravenous fluids and analgesics is given. Monitor for postoperative pain and infection. Also monitor for normal colorectal function. Stool softeners such as Miralax or canned pumpkin can be given if constipation due to abnormally hard stool occurs. Most dogs and cats do well after colopexy with improvement of their condition and low risk of recurrence of rectal prolapse or colonic volvulus. Dogs with perineal hernia will also require primary herniorrhaphy in addition to the colopexy.