One percent sodium carboxymethylcellulose prevents experimentally induced abdominal adhesions in horses.

OBJECTIVE: To evaluate the efficacy of 1% sodium carboxymethylcellulose (SCMC) for prevention of experimentally induced abdominal adhesions in horses. STUDY DESIGN: Prospective, controlled, experimental study. ANIMAL POPULATION: Twelve healthy adult horses. METHODS: The effect of 1% SCMC on adhesion formation was evaluated in 12 healthy horses by using an established model of serosal trauma to induce intraabdominal adhesions. After ventral median celiotomy, 2 separate areas of the jejunum were abraded, and three 2-0 chromic gut sutures were placed in each abraded area. Jejunal resection and end-to-end anastomosis was performed at 2 sites distant to the abrasion sites. In treated horses (n = 6), 2 L of 1% SCMC was applied to the intestine before and after intestinal manipulation. In control horses (n = 6), 2 L of saline solution were applied to the intestine before and after surgical manipulation. All horses were euthanatized 10 days after surgery, and the abdominal cavity was evaluated for adhesion formation. The frequency of intraabdominal adhesions between groups was compared with a chi-square test. Statistical significance was set at P <.05. RESULTS: All control horses had intraabdominal adhesions. Fibrous adhesions were associated with both jejunal abrasion sites in 5 control horses. Fibrous adhesions were also associated with 1 or both jejunal anastomotic sites in 5 control horses. Only 1 treated horse developed adhesions at the jejunal abrasion sites, and no adhesions were present at the anastomotic sites in the treated horses. There were significantly fewer adhesions in the SCMC treatment group compared with the control group (P <.05). CONCLUSION: In this experimental model, application of 1% SCMC reduced the frequency of intraabdominal adhesions at areas of serosal abrasion and at jejunal anastomotic sites. CLINICAL RELEVANCE: In horses at an increased risk for developing intraabdominal adhesions after intestinal surgery, the use of 1% SCMC during celiotomy may decrease the frequency of adhesion formation.

Effect of carboxymethylcellulose and a hyaluronate-carboxymethylcellulose membrane on healing of intestinal anastomoses in horses.

OBJECTIVE: To evaluate the effect of sodium carboxymethylcellulose (SCMC) or a hyaluronate-carboxymethylcellulose membrane (HA membrane) on healing of the small intestine in horses. ANIMALS: 18 healthy adult horses. PROCEDURE: Midline celiotomy and 2 jejunal resection-and-anastomosis surgeries were performed. In treated horses, SCMC (n = 6) or a HA membrane (6) was applied to the jejunum to cover the anastomosis. There were 6 untreated control horses. Horses were euthanatized 10 days after surgery. For each horse, 1 anastomosis was used for histologic examination, and the second was used to determine intestinal bursting strength. Intestinal bursting tension, serosal granulation tissue, serosal fibrin deposition, and width of the fibrous seal at the anastomosis were compared among groups. RESULTS: 3 control horses had adhesions associated with the anastomosis, but none of the treated horses had adhesions associated with the anastomosis. Mean thickness of fibrin deposited on the serosal surfaces for the SCMC and HA-membrane groups was significantly less than that for control horses. Mean thickness of serosal granulation tissue, width of fibrous seal between inverted musculature, inflammatory cell infiltrate scores, and bursting tension did not differ significantly among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Use of SCMC or application of a HA membrane to small intestinal anastomoses in horses resulted in fewer adhesions and decreased fibrin deposition, and it did not adversely affect anastomotic healing. In horses at increased risk for intra-abdominal adhesions, SCMC or application of HA membranes may decrease the frequency of adhesions without adversely affecting healing of small intestinal anastomoses.

Evaluation of a bioresorbable hyaluronate-carboxymethylcellulose membrane for prevention of experimentally induced abdominal adhesions in horses.

OBJECTIVE: To evaluate the efficacy of a bioresorbable hyaluronate-carboxymethylcellulose membrane (HA-membrane) for prevention of experimentally induced abdominal adhesions in horses. STUDY DESIGN: Experimental study. ANIMAL POPULATION: Twelve healthy adult horses. METHODS: The effect of an HA-membrane on adhesion formation was evaluated in 12 healthy horses using an established model of serosal trauma to induce adhesions. A ventral median celiotomy and two jejunal resections and end-to-end anastomoses were performed. Two separate jejunal areas were abraded, and three 2-0 chromic gut sutures placed in the abraded areas. In treated horses (n = 6), HA-membranes were applied to the jejunum to completely cover the anastomoses and abraded areas of jejunum. Nontreated horses (n = 6) served as controls. All horses were killed 10 days after surgery. The abdominal cavity was evaluated for adhesion formation. The frequency of intra-abdominal adhesions between groups was compared with a chi2 test with statistical significance set at P < .05. RESULTS: All control horses had intra-abdominal adhesions; fibrous adhesions were associated with both jejunal abrasion sites in 5 horses. One treated horse developed adhesions. There were significantly fewer adhesions in the HA-membrane-treated group (P < .0034). CONCLUSIONS: In this experimental model, application of an HA-membrane to a localized area of serosal trauma reduced the frequency of intra-abdominal adhesion formation. CLINICAL RELEVANCE: Application of an HA membrane may decrease the frequency of adhesions in horses at an increased risk of postoperative adhesion formation.

Removal of an ectopic left kidney through a ventral midline celiotomy in a calf.

A 4-month-old Holstein heifer was examined because of poor growth, weight loss, dysuria, hematuria, pyuria, and a palpable mass in the right caudal quadrant of the abdomen. Clinicopathologic abnormalities included hyperfibrinogenemia, hyperproteinemia, anemia, and leukocytosis, and were consistent with chronic inflammation. Results of ultrasonographic evaluation of the umbilical cord remnants were suggestive of urachal abscess formation. Transabdominal ultrasonography of the kidneys was attempted; the right kidney appeared normal, but the left kidney could not be imaged. The calf was anesthetized and a ventral midline celiotomy was performed. The left kidney was larger than normal, was multilobulated, and contained multiple abscess. It had also broken through the peritoneum and was located in the peritoneal cavity. Unilateral nephrectomy and resection of umbilical cord remnants were performed. The calf recovered without complications and was healthy 5 years later. In this calf, ventral midline celiotomy provided sufficient surgical exposure for removal of the ectopic left kidney and resection of umbilical cord remnants.

Urinary and biliary excretion of ergot alkaloids from steers that grazed endophyte-infected tall fescue.

Ergot alkaloids cause fescue toxicosis when livestock graze endophyte-infected (E+) tall fescue. Little is known about the bioavailability of the ergot alkaloid classes (lysergic acid, lysergic acid amides, or ergopeptine alkaloids) in livestock, and this hampers development of pharmacological strategies to ameliorate the toxicosis. One method used to determine bioavailability of ergot alkaloids is to examine urinary and biliary excretion patterns. Thus, our objectives were to compare ergot alkaloid excretion via urinary or biliary systems and to determine the rate of appearance or clearance of these alkaloids in cattle that were grazing E+ or endophyte-free (E-) tall fescue. In autumn 1996, bile and urine samples were collected from eight steers (203 kg), each grazing E+ and E- tall fescue, and total alkaloid excretion was quantified using competitive ELISA. Approximately 96% of the ergot alkaloids were excreted in urine. The same steers were used to examine the rate of appearance in, or clearance from, urine when switched from E+ to E-, or from E- to E+, pastures in comparison with steers that were continuously grazing E+ or E- tall fescue at 0, 2, 5, and 7 d. Steers were returned to their original pastures after 7 d, and urine was collected at 2, 5, and 7 d. Urinary alkaloid concentrations in steers switched from E- to E+ pastures were similar (P = .55) to those in steers that continuously grazed E+ tall fescue after 2 d. Steers switched from E+ to E- pastures had urinary alkaloid concentrations similar (P = .91) to those in steers that continuously grazed E- pastures after 2 d. In 1997, two trials were conducted in which steers (191 kg) were switched or remained on E+ or E- pastures, and urine was collected at 0, 12, 24, 48, and 96 h to estimate rate of alkaloid appearance or clearance. Steers switched from E- to E+ 1) had about 33% as much urinary alkaloids as steers grazing E+ pasture after 12 h, 2) were not different after 24 h (P = .76), 3) had twice those of the E+ steers at 48 h (P < .05), and 4) were not different after 96 h. Steers switched from E+ to E- tall fescue had approximately 33% less (P < .05) urinary alkaloids than those grazing E+ at 12 h, 67% less (P < .05) at 24 and 48 h, and were not different (P = .86) from steers continuously grazing E- pastures after 96 h. Urinary alkaloid excretion patterns were similar to ergot alkaloid solubility patterns from in vitro digestion of E+ tall fescue. We suggest that alkaloids, liberated from the forage by ruminal microorganisms, were rapidly absorbed as lysergic acid amides and biotransformed ergopeptine alkaloids.

Intraperitoneal use of sodium carboxymethylcellulose in horses undergoing exploratory celiotomy.

The effect of intraperitoneal sodium carboxymethylcellulose (SCMC) administration on clinical outcome and survival was evaluated in horses undergoing exploratory celiotomy for acute gastrointestinal disease. Comparison of variables was made retrospectively between 44 horses that had SCMC and 92 horses (controls) not treated with SCMC. Mean age, body weight, heart rate, packed cell volume and plasma total protein of horses at admission, and convalescent period were not significantly different between control and SCMC groups. No significant differences were noted between control horses and SCMC horses with respect to incisional infection, hernia formation, recurrent episodes of colic, clinical outcome, and long-term survival (> 6 months). Seventy-six (83%) control horses and 34 (77%) SCMC horses survived long-term. Seventy (76%) control horses and 30 (68%) SCMC horses survived without complications and returned to their previous use. These results suggest that intraperitoneal use of SCMC does not adversely affect abdominal incisional wound healing, clinical outcome or long-term survival, however, the efficacy of SCMC in prevention of postoperative intestinal adhesions in horses requires further investigation.

Excision of intralaryngeal granulation tissue in 25 horses using a neodymium:YAG laser (1986 to 1991).

Granulation tissue masses arising from the axial surface of the arytenoid cartilage in 25 horses were excised using a contact neodymium:yttrium aluminum garnet laser. A technique that eliminated the need for general anesthesia or laryngotomy was developed for transen-doscopic removal of the masses in standing horses. Nineteen racehorses made abnormal upper respiratory tract noises or their performance was decreased, whereas six horses not used for racing had a history of stertor (five horses) or epistaxis after nasogastric intubation (one horse). Thoroughbreds were significantly (p = .0126) overrepresented compared with the hospital population. The granulation tissue masses were successfully excised and the defect healed in all 25 horses, although a second excision of granulation tissue regrowth was necessary in four horses. In 21 horses, the underlying chondrosis did not progress appreciably. In four horses with preexisting moderate arytenoid cartilage thickening and concurrent laryngeal abnormalities, the surgery site healed but the underlying chondrosis progressed substantially. Twelve of 19 (63%) racehorses returned to race at least three times after the surgery. Of the 19 racehorses, five had only slight arytenoid cartilage involvement whereas 14 had moderate cartilage thickening or concurrent laryngeal pathology. All five horses with slight apparent arytenoid cartilage involvement and no concurrent laryngeal pathology returned to racing. Seven of the 14 horses (50%) with moderate underlying cartilage thickening or concurrent laryngeal pathology returned to racing. The six horses not used for racing returned to their previous activity without further respiratory problems.

Partial arytenoidectomy in the horse using an extralaryngeal approach.

An extralaryngeal approach to partial arytenoidectomy in the horse was developed by in vitro experiments on isolated larynges and then on intact equine cadavers. The goals of the approach were to preserve the laryngeal mucosa, eliminate the need for a laryngotomy or tracheotomy, and minimize postoperative complications. The new approach was evaluated in seven horses with normal upper respiratory tracts. Left laryngeal hemiplegia was surgically created, and, after a 30-day convalescence, left partial arytenoidectomy was performed using an extralaryngeal approach. The left-to-right hemilaryngeal ratio was calculated before and after left recurrent laryngeal neurectomy and 60 days after partial arytenoidectomy. Left partial arytenoidectomy was successfully completed in all horses without performing a laryngotomy or tracheotomy. Preservation of the laryngeal mucosa (6/7 horses) and apparent stabilization of the adjacent soft tissue (6/7 horses) was achieved. In one horse, a 1-cm laryngeal mucosal tear healed without complication, and in another some collapse of adjacent soft tissue occurred when a retention suture failed. The mean left-to-right hemilaryngeal ratio was significantly increased compared to horses with left laryngeal hemiplegia, but it remained significantly less than the pre-recurrent laryngeal neurectomy ratio (p < .05). Coughing, aspiration, and airway narrowing were not observed. Partial arytenoidectomy could be reliably performed through an extralaryngeal approach in horses with a normal underlying arytenoid cartilage with preservation of the laryngeal mucosa.

Osteochondritis dissecans of the medial trochlear ridge of the talus in a calf.

Osteochondritis dissecans of the proximal aspect of the medial trochlear ridge of the talus was found to be causing lameness and tarsocrural joint effusion in a male Limousin calf. Arthroscopy via a dorsolateral approach was unsuccessful in revealing the lesion in this calf. A caudomedial arthrotomy or medial malleolar osteotomy, which can be used to gain access to lesions of the medial trochlear ridge in dogs, was not attempted. The lameness gradually worsened, and the calf was slaughtered.