Technique-associated outcomes in horses following large colon resection.

OBJECTIVE: To compare survival and complications in horses undergoing large colon resection with either sutured end-to-end or stapled functional end-to-end anastomoses. STUDY DESIGN: Retrospective cohort study. ANIMALS: Twenty-six client-owned horses with gastrointestinal disease. METHODS: Retrospective data were retrieved from the medical records of 26 horses undergoing colectomy, including 14 horses with sutured end-to-end and 12 horses with stapled functional end-to-end anastomoses, between 2003 and 2016. Records were evaluated for signalment, medical and surgical treatments, and survival to hospital discharge. Long-term follow-up was obtained through owner contact. Continuous variables were compared with Mann-Whitney tests. Fisher's exact testing was used to compare survival to hospital discharge. Survival time was compared by constructing Kaplan-Meier survival curves and performing log-rank curve comparison testing. RESULTS: Mean age of horses undergoing colectomy was 13 years. Reason for colectomy was prophylaxis (12) or salvage (14). Mean surgical time was 169 minutes. Mean hospitalization time was 9 days, which did not differ with anastomosis type (P = .62). Nine of 12 horses undergoing stapled functional end-to-end anastomosis and 12 of 14 horses undergoing sutured end-to-end anastomosis survived to hospital discharge (P = .63). Survival time did not differ with anastomosis technique (P = .35). CONCLUSION: Short- and long-term survival outcomes are not different between sutured end-to-end or stapled functional end-to-end anastomoses in horses undergoing colectomy.

A review of 18 cases of feline colonic adenocarcinoma treated with subtotal colectomies and adjuvant carboplatin.

Feline colonic adenocarcinoma is a locally invasive, highly metastatic tumor that is most often treated with wide surgical excision (subtotal colectomy) and systemic chemotherapy either with or without nonsteroidal anti-inflammatory medications. In this retrospective study, the outcome of subtotal colectomy and adjuvant carboplatin in 18 client-owned cats is described. The median carboplatin dose was 200 mg/m(2) (range, 200-254 mg/m(2)) q 4 wk with a median of five doses/cat (range was two to seven doses/cat). Limited toxicities were noted. Positive prognostic factors for the disease-free interval included cats that had weight loss as a presenting sign (P < 0.036) and negative prognostic factors for median survival included nodal and distant metastasis (178 versus 328 days and 200 versus 340 days, respectively). The median disease-free interval was 251 days (range, 37-528 days) and the median survival time was 269 days (range, 40-533 days). Subtotal colectomy and adjuvant carboplatin is a safe and potentially effective treatment for cats with colonic adenocarcinoma.

Subtotal colectomy by rectal pull-through for treatment of idiopathic megacolon in 2 cats.

Surgical management of idiopathic megacolon is described in 2 cats by a rectal pull-through with subtotal colectomy performed outside of the abdomen. This newly described technique facilitates access to the rectum for suturing an anastamosis without the need for pubic osteotomy and with minimal risk of abdominal contamination.

Outcome of surgical treatment of perineal hernia in cats: 36 cases (2013-2019).

OBJECTIVES: To report the clinical presentation, complications, and long-term outcomes of cats treated for perineal hernia with modified internal obturator muscle transposition. METHODS: The medical records of cats surgically treated for perineal hernia between 2013 and 2019 were reviewed and an owner questionnaire was conducted to determine long-term outcome. RESULTS: Thirty-six cats were included in the study: 34 had bilateral and two unilateral hernias. Of these 36, 24 (67%) were male neutered with a median age of 10 (range: 1 to 18) years. The complication rate was low, however, one cat experienced a major postoperative complication: rectal prolapse requiring revision surgery 48 hours postsurgery. Short-term outcomes were available for 32 of 36 (89%) cats. Of the 32, 23 were examined 6 weeks postoperatively, and a telephonic consultation was performed for an additional nine of 32. Of the 23 cats examined directly, none had recurrence. Overall 12 of 32 experienced short-term postoperative tenesmus which resolved in nine of 12 (75%). Long-term outcomes were available for 31 of 36 cats (86%), with a median of 18.5 (6 to 89) months follow-up. A good outcome was achieved in 23 of 31 (74%) whereas three of 31 (10%) had fair outcomes and five of 31 (16%) had a poor outcome. Of the five cats with a poor outcome, two required subtotal colectomy to manage clinical signs related to megacolon, two were euthanised following a return of clinical signs, and one developed unilateral recurrence. CLINICAL SIGNIFICANCE: Perineal hernia should be considered in cats presenting with tenesmus or recurrent obstipation. Surgical treatment of perineal hernias in cats can result in good owner-assessed long-term outcome.

Transillumination Techniques for Vessel Identification During Small Colon Resection in Six Horses.

BACKGROUND: Transillumination has been described in human surgery to improve vessel visualization but has not been described in horses. Since the equine mesocolon contains a great amount of fat which restricts visualization of the vessels, this technique could be useful during small colon resection. OBJECTIVES: To describe transillumination of the mesocolon to provide an improved vessel identification during resection and anastomosis of the small colon in horses. METHODS: Data of horses that underwent resection and anastomosis of small colon were recorded. Two transillumination techniques were used during resection and anastomosis of small colon. In a first technique, used on three horses, the operating lamp was used. It was lowered and tilted so that the assistant surgeon could lift the small colon so that the mesentery was between the lamp and the first surgeon eyes. In a second technique, used on further three horses, a smartphone with a rear LED flashlight turned on was placed into a sterile rectal sleeve. The device was placed on the surgical field and the portion of small colon to be resected was then laid over the smartphone, to backlight the vessels. The vessels were then identified and ligated. RESULTS: Six horses referred for acute colic that underwent resection and anastomosis of the small colon were included in the study. Using both transillumination technique the mesocolon was backlit and the vessels were clearly and easily identified, dissected, ligated, and transacted without complications. The smartphone technique subjectively ensured a better operating position for the surgeon and less fatigue for the assistant. CONCLUSIONS: Transillumination techniques are useful to avoid damage when ligating vessels and using the flashlight of a smartphone is easier and provide safer and more accurate transection of them during small colon resection and anastomosis.

Evaluation of outcomes following subtotal colectomy for the treatment of idiopathic megacolon in cats.

OBJECTIVE: To evaluate outcomes in cats undergoing subtotal colectomy for the treatment of idiopathic megacolon and to determine whether removal versus nonremoval of the ileocecocolic junction (ICJ) was associated with differences in outcome. ANIMALS: 166 client-owned cats. PROCEDURES: For this retrospective cohort study, medical records databases of 18 participating veterinary hospitals were searched to identify records of cats with idiopathic megacolon treated by subtotal colectomy from January 2000 to December 2018. Data collection included perioperative and surgical variables, complications, outcome, and owner perception of the procedure. Data were analyzed for associations with outcomes of interest, and Kaplan-Meier survival time analysis was performed. RESULTS: Major perioperative complications occurred in 9.9% (15/151) of cats, and 14% (12/87) of cats died as a direct result of treatment or complications of megacolon. The median survival time was not reached. Cats with (vs without) a body condition score < 4/9 (hazard ratio [HR], 5.97), preexisting heart disease (HR, 3.21), major perioperative complications (HR, 27.8), or long-term postoperative liquid feces (HR, 10.4) had greater hazard of shorter survival time. Constipation recurrence occurred in 32% (24/74) of cats at a median time of 344 days and was not associated with retention versus removal of the ICJ; however, ICJ removal was associated with long-term liquid feces (OR, 3.45), and a fair or poor outcome on owner assessment (OR, 3.6). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that subtotal colectomy was associated with long survival times and a high rate of owner satisfaction. Removal of the ICJ was associated with less favorable outcomes in cats of the present study.

Long-term results of subtotal colectomy for acquired hypertrophic megacolon in eight dogs.

OBJECTIVES: To evaluate the long-term results of subtotal colectomy for acquired hypertrophic megacolon in the dog. METHODS: Eight dogs with acquired hypertrophic megacolon underwent subtotal colectomy with preservation of the ileocolic junction. Long-term follow-up was obtained by clinical records and telephone interviews with the owners. RESULTS: Eight large-breed dogs (age range: 6 to 12 years; mean age: 10.75 years) were enrolled. The use of bone meal, low levels of exercise, chronic constipation with dyschesia and tenesmus refractory to medical management were factors predisposing dogs to acquired hypertrophic megacolon. The diagnosis was confirmed in all animals by abdominal palpation, plain radiography and postoperative histopathological findings. There were no intraoperative complications. One dog died as a result of septic peritonitis. The clinical conditions (that is, resolution of obstipation and stool consistency) of the remaining seven dogs were improved at discharge; all animals returned to normal defecation in five to 10 weeks (mean: 7.3 weeks) and were alive 11 to 48 months (mean: 40.5 months) after surgery. CLINICAL SIGNIFICANCE: Predominantly bony diet and/or low levels of physical activity may predispose dogs to acquired hypertrophic megacolon. Our results emphasise the long-term effectiveness of subtotal colectomy with preservation of the ileocolic junction in this condition.

Type Ia (spherical) communicating colonic duplication in a dog treated with colectomy.

A six-month-old Labrador retriever presented for investigation of a colonic mass identified as an incidental finding during exploratory coeliotomy. Computed tomography identified a lesion in the colon which occupied part of its lumen and shared blood supply with the remainder of the colon. The lesion was suspected to be a colonic duplication and it was excised by segmental colectomy during exploratory coeliotomy. Histopathology from the excised colon confirmed the diagnosis of a colonic duplication. The dog recovered uneventfully and had no complications. To the authors' knowledge, this is the first report of an asymptomatic, spherical, communicating colonic duplication and the first report to describe segmental colectomy for the management of this condition in veterinary patients.

Rectovaginal fistula following colectomy with an end-to-end anastomosis stapler for a colorectal adenocarcinoma.

An 11-year-old, female neutered Labrador retriever was presented with a micro-invasive differentiated papillar adenocarcinoma at the colorectal junction. A colorectal end-to-end anastomosis stapler device was used to perform resection and anastomosis using a transanal technique. A rectovaginal fistula was diagnosed two days later. An exploratory laparotomy was conducted and the fistula was identified and closed. Early dehiscence of the colon was also suspected and another colorectal anastomosis was performed using a manual technique. Comparison to a conventional manual technique of intestinal surgery showed that the use of an automatic staple device was quicker and easier. To the authors' knowledge, this is the first report of a rectovaginal fistula occurring after end-to-end anastomosis stapler colorectal resection-anastomosis in the dog. To minimise the risk of this potential complication associated with the limited surgical visibility, adequate tissue retraction and inspection of the anastomosis site are essential.

Granuloma Due to Oxidized Regenerated Cellulose in an Aged Rhesus Macaque (Macaca mulatta).

Bioabsorbable hemostatic agents such as oxidized regenerated cellulose are widely used to control intraoperative diffuse capillary bleeding. Compared with electrocautery or ligation, oxidized regenerated cellulose has the advantage of controlling bleeding without occluding the vessel lumen or causing thermal injuries to adjacent tissue. Although the manufacturer recommends removal of the material once hemostasis is achieved, oxidized regenerated cellulose is a bioabsorbable hemostatic agent and is often left in the surgical bed to prevent subsequent bleeding after surgical closure. However, noninvasive imaging techniques have revealed granulomatous foreign-body reactions that mimic infection or tumor recurrence. We present a case report of sterile peritonitis and granuloma formation secondary to the presence of oxidized regenerated cellulose after intestinal resection to excise a colonic adenocarcinoma in an aged rhesus macaque.

Surgical management of constipation.

There are many recognised causes of constipation in the cat and the management of the condition depends on the clinician's ability to recognise the appropriate aetiology in each case. Most surgery therapies for constipation in the cat are related to the management of idiopathic megacolon, although causes such as pelvic outlet obstruction, complications of neutering surgery, perineal herniation, and malunion pelvic fractures may also require surgical intervention. Currently, the surgical management of megacolon consists of subtotal colectomy with the recommendation that the ileocolic junction be preserved. The procedure, in general, is associated with few life-threatening complications although the majority of individuals will experience a transient period of loose stool formation in the immediate post-operative period. In the majority of cases, the long-term outcome following subtotal colectomy is considered excellent.

Large intestinal capacity, retention times, and turnover rates of particulate ingesta associated with extensive large-colon resection in horses.

Fecal excretion of a particulate marker, ytterbium (Yb), was evaluated in 9 horses before surgery and 3 weeks, 3 months, and 6 months (4 trials) after sham-operation (group 1; n = 3) or extensive large colon resection (group 2; n = 6). Fecal excretion curves of total Yb excretion, loge Yb excretion, % Yb excretion, loge % Yb excretion, and cumulative % Yb excretion were evaluated, and kinetic analysis was performed on the loge Yb excretion curves to detect mixing pools and to calculate the fractional rate of particulate passage, turnover rate, and pool size. Calculations were performed to determined transit time, mean overall retention time, adjusted mean retention time, peak time, and disappearance time. Values were statistically analyzed to determine differences between groups and among trials (P less than 0.05). Group-2 horses had significantly shorter transit, peak, and mean overall retention times, compared with preoperative values and with values for group-1 horses. Two mixing pools were identified: a slower emptying pool of 5.7% hour-1 (k1) and a faster emptying pool of 12.3% hour-1 (k2). The rate of passage from the first pool (k1) was not altered by colon resection, and was interpreted as being most influenced by the cecum. In further support of this interpretation, the capacity of the k1 pool approximated the capacity of the cecum (17 L). The capacity of the k1 pool significantly expanded by 6 months in the resected horses. the rate of passage from the second pool (k2) significantly increased initially after colon resection (3 weeks and 3 months), but returned to preoperative values by 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Fiber digestion and voluntary intake in horses after adaptation to extensive large-colon resection.

Each of 3 digestion trials (3 forage diets) was performed on 2 groups of horses 6 to 12 months after sham operation (group 1; n = 3) or large-colon resection (group 2; n = 5). Diets were alfalfa pellets, alfalfa hay, and grass hay. Feed and fecal analyses were performed to determine apparent digestion of dry matter, organic matter, and crude protein and true digestion of dry matter, organic matter, crude protein, total plant cell wall, hemicellulose, cellulose, and lignin. Additional fecal and metabolic variables determined were percentage of fecal water, total fecal water, metabolic organic matter, metabolic crude protein, and metabolic nitrogen. Large-colon resection decreased the digestion of plant cell wall because of decreased digestion of cellulose in alfalfa pellet and grass hay diets, but not in alfalfa hay diet. Insufficient digestible energy and/or protein from grass hay was obtained by horses with colon resection, and significant (P less than 0.05) weight loss was observed. Voluntary intake was significantly (P less than 0.05) increased by horses with colon resection. Of the diets studied, alfalfa hay was the most appropriate forage diet, compared with average grass hay and alfalfa pellet diet, for horses after extensive large-colon resection. Additionally, horses with colon resection may have higher levels of feed intake than do horses without colon resection.

Digestion, fecal, and blood variables associated with extensive large colon resection in the horse.

Nutritional alterations were evaluated in 9 horses before surgery and 3 weeks, 3 months, and 6 months (4 total trials) after sham operation (group 1; n = 3) or extensive large colon resection (group 2; n = 6). Feed and fecal analyses were performed to determine apparent digestion of dry matter, organic matter, crude protein, calcium, phosphorus, magnesium, potassium, manganese, zinc, copper, and iron, and true digestion of dry matter, organic matter, crude protein, total plant cell wall, hemicellulose, cellulose, and lignin. Additional fecal and metabolic variables included the percentage of fecal water (water in the feces), total fecal water, metabolic organic matter, metabolic crude protein, and metabolic nitrogen. A CBC and standard series of biochemical tests were performed. Large colon resection decreased (P less than 0.05) the true digestion of dietary crude protein and cellulose and apparent digestion of phosphorus, and it increased the fecal metabolic matter and water loss. Total fecal output increased 45% and total fecal water increased 55%. Phosphorus digestion was decreased (P less than 0.05) in group-2 horses, but effects of this were not detected on analysis of blood variables or on physical examination. Nevertheless, after extensive large colon resection, horses can regain body weight lost after surgery and have no overt physical changes when fed an alfalfa pellet diet that meets greater-than-maintenance requirements. Ad libitum water access is suggested, because these horses may have to consume 2 gal/day more than would normal horses.

Digestion in horses after resection or ischemic insult of the large colon.

The effect of 60% resection of the large colon vs ischemic insult without resection on the ability of horses to digest grass hay was investigated. Digestion trials were performed on 9 horses before surgery (base line) and 3 weeks, 6 weeks, and 6 months after surgery. The percentage of apparent digestion of crude protein, crude fiber, nitrogen-free extract, calcium, phosphorus, magnesium, manganese, copper, and zinc was calculated. Horses that had resection (n = 5) had decreased apparent digestion of crude protein, crude fiber, and phosphorus 3 weeks after surgery, compared with those in horses with ischemic insults (n = 4) and with base-line values. Horses with ischemic insults also had a decrease in crude protein digestion 3 weeks after surgery, compared with base-line values. All horses returned to base-line values of digestion at the 6-month trials, although horses that had resection had higher fecal concentrations of phosphorus and nitrogen-free extract than did horses with ischemic insult. During the study, all horses had maintained good body condition.

Alteration of intestinal enzyme activities associated with extensive large-colon resection in horses.

Lactase, maltase, sucrase, and alkaline phosphatase activities were determined in the intestinal mucosa from 3 locations in the small intestine and 4 locations in the large intestine 1 year after extensive large-colon resection (group 1; n = 5) and 1 year after sham operation (group 2; n = 3) in horses. Lactase, maltase, and sucrase activities were similar (P greater than 0.05) between group-1 and group-2 horses in all locations measured in the intestinal tract. Alkaline phosphatase activity in the remaining large colon of group-1 horses was significantly (P less than 0.05) greater than the activity in the large colon of group-2 horses. Decreased apparent digestion of phosphorus and a negative phosphorus balance are persistent features of large-colon resection in horses. Increases in alkaline phosphatase activity in the remaining colon of horses with extensive large-colon resection may be a specific functional adaptive mechanism that attempts to counteract the derangements in phosphorus metabolism.

Subtotal colectomy for treatment of acquired megacolon in the dog and cat.

The case records of 4 cats and 1 dog with megacolon and constipation were reviewed to study the history, clinical signs, pathologic changes, and longterm results of surgical treatment. The 4 cats had idiopathic megacolon. The dog had megacolon secondary to dietary indiscretion. All animals had radiographic evidence of a large colon, which was confirmed by exploratory coeliotomy. Two of the cats and the dog had an intraoperative finding of megacecum as well. Subtotal colectomy was performed in all cases, with the ileocolic valve being removed in 3 of these cases. End-to-side anastomosis was used to restore the integrity of the bowel. All animals were treated successfully with this surgical technique, as judged by clinical response and owner satisfaction. Histologically, there were no consistent lesions to explain the cause of this disease in the cats.

Treatment of right dorsal ulcerative colitis in a horse.

Excessive administration of phenylbutazone was associated with development of right dorsal ulcerative colitis. The clinical signs of right dorsal colitis include chronic colic and weight loss. The laboratory abnormalities include panhypoproteinemia and a high WBC count in the abdominal fluid. Medical management of the chronic colic and protein-losing enteropathy associated with the ulcerative lesions in the right dorsal colon and surgical bypass of the right dorsal colon did not result in long-term resolution of clinical signs. Resection of the ulcerated right dorsal colon through a right lateral approach at the 16th rib resulted in resolution of intestinal protein loss and colic. The results of this case suggest that surgical resection of the ulcerated right dorsal colon may be the recommended treatment for right dorsal ulcerative colitis.

Panfibrinonecrotic colitis in a dog treated by subtotal colectomy.

A dog with signs of small intestinal disease developed signs of severe large intestinal disease after being treated with multiple agents. Endoscopy and biopsy revealed total destruction of the colonic mucosa, which necessitated total parenteral nutrition plus subtotal colectomy. It was hypothesized that the multiple prior treatments led to an overgrowth of toxigenic or cytotoxic bacteria, which caused this colonic mucosal destruction.

Large colon resection and anastomosis in horses.

Large colon resection and anastomosis was performed in 11 horses at various levels of the colon, using several surgical methods. The level of resection ranged from the pelvic flexure to the cecocolic ligament. Nine of 11 horses survived and at follow-up (4 months to 7 years) were free of clinical signs referable to disease of the gastrointestinal tract. Seven horses could be evaluated as to athletic or reproductive function and all returned to original potential.