Treatment of laryngeal hemiplegia in horses by prosthetic laryngoplasty, ventriculectomy and vocal cordectomy.

The medical records of 80 horses treated for left laryngeal hemiplegia by prosthetic laryngoplasty, ventriculectomy and vocal cordectomy were examined, first to compare the subjective and objective success rates for groups of horses of different ages and used for different purposes, and secondly, to compare the efficacy of including vocal cordectomy in the surgical protocol with published success rates for laryngoplasty and ventriculectomy alone. Subjectively, 70 per cent of the horses were said to have had a successful surgical outcome. The success rate for thoroughbred racehorses (66 per cent) was lower than for other breeds (90 per cent) on the basis of a subjective assessment by owners and trainers. Thoroughbreds two years old or younger had a success rate of 69 per cent, but older thoroughbreds had a success rate of 61 per cent. Of the 17 horses for which an objective performance index could be calculated, 10 (59 per cent) had an improved performance postoperatively. There was a nearly significant association between the objective and subjective assessments (P=0.078). Six of 69 horses (8.7 per cent) continued to make a respiratory noise after surgery. The subjective assessment of success did not appear to correlate with the objective measure of success used in this study and age had no apparent association with a successful surgical outcome. Inclusion of a vocal cordectomy in the surgical protocol may be more important in the eradication of postoperative respiratory noise than in improving clinical success rates.

Colic surgery in 206 juvenile thoroughbreds: survival and racing results.

The purpose of our study was to determine the types of lesions that cause colic in juvenile Thoroughbreds, factors associated with these lesions and the subsequent survival and athletic performance of the juveniles. The age of juvenile Thoroughbreds requiring surgical exploration for abdominal pain has an influence on the type of lesion causing colic. The short-term survival rate (discharge from the hospital) after colic surgery for foals was 85% and was strongly influenced by the lesion causing colic. Thirteen percent of juveniles recovered from the first surgery experienced another severe colic episode requiring additional surgery or euthanasia. Eight percent of foals recovered from the first celiotomy developed adhesions. Adhesion formation was related to the initial lesion causing colic and the foals' age at the first surgery. Foals being suckled (15 days to 6 months) were at greatest risk for adhesions and more frequently required multiple surgeries. Juvenile Thoroughbreds that had a celiotomy were significantly less able to race (63%) than their unaffected siblings (82%), and age at the initial surgery was associated with the percentage of horses that raced. However, affected foals able to race won as much money, raced as often, and made as many starts as their siblings. Colic and surgical treatment have a negative impact on athletic performance, but the majority of foals discharged from the hospital after colic surgery will perform athletically as adults.

Caecal impactions managed surgically by typhlotomy in 10 cases (1988-1998).

Surgical management of caecal impactions has included several different procedures suggested over the years. Complete bypass of the caecum through an ileocolic or jejunocolic anastomosis has become common practice for first time caecal impaction management, especially when dysfunction is suspected. In our practice, however, caecal impactions have been managed surgically by typhlotomy alone and of the 10 cases (July 1988-June 1998), 9 underwent surgery for first time caecal impactions, received a typhlotomy, and had survived an average of 43 months at time of case review. At the time of surgery, all were considered to have a dysfunctional caecum. All horses received routine postoperative care with the addition of anthelmintics as recovery of Anoplocephala perfoliata occurred in several cases. Typhlotomy should be considered an acceptable technique for surgical management of first time caecal impactions. Postoperative pyrantel pamoate and larvicidal anthelmintics should also be considered.

Effect of omentectomy on adhesion formation in horses.

OBJECTIVE: To determine if omentectomy would decrease the frequency of postoperative intraabdominal adhesions. STUDY DESIGN: Retrospective study. ANIMALS OR SAMPLE POPULATION: 44 horses that had either two ventral median celiotomies or a ventral median celiotomy and a necropsy more than 4 days later; 19 of these horses had their omentum removed at the initial surgery. METHODS: Data retrieved from the records included location and type of intraabdominal adhesions; location of the surgical lesion; relationship of adhesions to the surgical lesion; surgical procedures; duration of initial surgery; time interval between procedures; age, gender, and breed of the horse; and clinical outcome. Fisher's exact test was used to evaluate the association between categorical explanatory and outcome variables. The effect of potential risk factors on the incidence rate of adhesion formation was estimated using a proportional hazards regression model. RESULTS: Of 25 horses in the nonomentectomy group, 15 (60%) had postoperative adhesions that resulted in the need for a second surgical intervention, whereas of 19 horses that had omentectomy initially, only 4 (21%) had postoperative adhesions that required a second procedure. Rate of adhesion formation was higher in horses that did not have omentectomy initially (incidence ratio rate [IRR], 0.46; 90% confidence interval [CI], 0.18 to 1.19). At initial surgery, 24 horses had a small intestinal lesion, and 20 horses had a large intestinal lesion. Fifteen horses (63%) with small intestinal lesions subsequently developed adhesions compared with four horses (20%) with an initial large intestinal lesion (P = .006). At the second procedure, small intestine lesions were identified in 32 horses and large intestine lesions in 12 horses (1 horse had both small and large intestine lesions), and 1 horse had a gastric lesion. Adhesions were identified as the cause of colic signs in 19 (61%) horses with small intestinal lesions and in none of the horses with large intestine lesions. The frequency of adhesion development leading to colic associated with only the small intestine at the second surgery or necropsy was significantly greater (P = .001) than the frequency only in the large intestine. CONCLUSIONS: Omentectomy reduced the rate of postoperative adhesion formation. Adhesions are more likely to occur after small intestinal surgery and if they do occur likely involve the small intestine. CLINICAL RELEVANCE: Omentectomy is a safe procedure and should be considered prophylactically for reduction of adhesion formation after abdominal surgery in horses.

A modified technique for extensive large colon resection and anastomosis in horses.

OBJECTIVE: To describe an alternative technique for large colon resection and anastomosis in horses. STUDY DESIGN: Retrospective study of clinical patients. ANIMAL POPULATION: 37 horses that had ventral midline celiotomies between July 1, 1990, and July 1, 1994. METHODS: Large colon resection and anastomosis was performed using a modification of previously described techniques. Modifications include mesocolon ligation with a stapling device and an end-to-end apposition of the right ventral and right dorsal colon. RESULTS: Twenty-one of the 37 horses were discharged from the hospital without complications. Two horses were euthanatized immediately after recovery from anesthesia because of hindlimb fracture. Fourteen horses were euthanatized in the initial postoperative period because of persistent endotoxemia and abdominal pain. CONCLUSIONS: The described technique is a safe, reliable method for large colon resection and anastomosis in horses. CLINICAL RELEVANCE: The described technique is fairly simple to perform and requires less surgical time compared with other techniques.

Large colon resection.

Strangulating large colon volvulus presents the surgeon with the dilemma of determining the extent of compromise to the affected tissue and the most appropriate surgical treatment of this tissue. This decision is complicated because there is a significant volvulus recurrence rate. Large colon resection and anastomosis is the most aggressive treatment option but prevents recurrence and may provide an alternative to euthanasia for some horses.

Diaphragmatic hernia repair in three young horses.

OBJECTIVE: This clinical report describes surgical correction of diaphragmatic hernia in three young horses. STUDY DESIGN: Retrospective investigation of medical records and subsequent racing performance. ANIMALS: Three young horses with diaphragmatic hernia. RESULTS: Three young horses with signs of abdominal pain had diaphragmatic hernia causing small intestinal strangulation. The strangulated small intestine was resected and an end-to-end jejuno-jejunal (two horses) or a side-to-side jejuno-cecal anastomosis (one horse) was performed. Diaphragmatic hernias were closed with a continuous suture pattern. All horses recovered and raced. No difference in race records was found between the subject horses and their siblings. One subject horse died of colic at 5 years of age, but the cause of the colic was undetermined. The remaining two horses are in use as broodmares and have produced multiple foals without recurrence of signs of diaphragmatic hernia. CONCLUSIONS: Diaphragmatic hernias can be repaired in horses. These horses can achieve race records similar to their siblings and can produce foals without recurrence of signs of diaphragmatic hernia.

Successful pregnancy after partial hysterectomy in two mares.

Infertility was associated with a uterine mass in 2 Thoroughbred mares. Both mares had produced live foals, but had been barren for 2 years, despite repeated breedings. Each mass was removed through a right ventral paramedian incision. Histologic examination of the masses revealed a leiomyoma and an ovarian abscess. In 1 mare, approximately 30% of 1 uterine horn was removed because of tumor attachment; in the other mare, approximately 50% of 1 uterine horn was removed because of adhesions to the ovarian abscess. Pregnancy information was available for both mares for the 3 years after surgery; each mare had produced 2 healthy foals and was pregnant with a third.

Performance analysis after prosthetic laryngoplasty and bilateral ventriculectomy for laryngeal hemiplegia in horses: 70 cases (1986-1991).

Medical records of 70 horses diagnosed with left laryngeal hemiplegia that were treated by use of prosthetic laryngoplasty combined with bilateral ventriculectomy were examined. Degree of arytenoid cartilage abduction that had resulted from the prosthesis had been graded before the horse was discharged from the hospital. Follow-up information through owner/trainer questioning was acquired for 55 horses. Information concerning the type and frequency of complications, if any, was recorded, along with a determination of owner/trainer satisfaction regarding surgical results. Race records were acquired for 42 horses and were used to aid in evaluation of postoperative performance. After surgery, Thoroughbred racehorses had a much lower success rate (48%; 19 of 40 horses), determined from owner/trainer questioning, than did all breeds in the study that were not intended for racing (93%; 14 of 15 horses). Younger Thoroughbred race-horses had a better success rate (70%; 14/20) than did those > or = 3 years old (25%; 5/20). Degree of arytenoid abduction had little effect on outcome, except that horses with maximal abduction (grade 5) of the arytenoid cartilage had a higher prevalence of complications and poor correction. The 2 most prevalent complications were exercise intolerance (42%; 23 of 55 horses) and continuing noise when exercising (47%; 26 of 55 horses).

Left dorsal displacement of the colon with splenic adhesions in three horses.

Three horses underwent exploratory celiotomy because of signs of acute abdominal pain. At surgery, all horses were diagnosed as having left dorsal displacement of the large colon. Each surgery was complicated by fibrous adhesions of the spleen to the body wall. All horses had previously undergone abdominal surgery for colic. In these cases, it appeared that the left large colon displaced cranially and then entered the renosplenic space from a cranial to caudal direction. Adhesions of the spleen to the body wall would prevent correction of left dorsal displacement of the large colon by the rolling technique.

Use of ultrasound in horses for diagnosis of left dorsal displacement of the large colon and monitoring its nonsurgical correction.

During a 28 month period, 82 horses with clinical signs of abdominal pain were examined for left dorsal displacement of the large colon (LDDLC) using percutaneous ultrasound. Left dorsal displacement of the large colon was diagnosed when a gas echo dorsal to the spleen obliterated the dorsal splenic border, or when the colon was observed lateral to the spleen. In 42 horses, ultrasound confirmed a diagnosis of LDDLC and 40 horses had no evidence of LDDLC. There were five false negative results and no false positives. In four horses with LDDLC, the colon was displaced between the spleen and body wall; three of these colic episodes resolved with medical therapy and the fourth required a celiotomy to relieve a sand impaction. The remaining 38 horses had a renosplenic entrapment; surgical correction was elected in 4 horses, 21 horses were corrected by a nonsurgical rolling procedure, 12 were corrected at surgery after an unsuccessful rolling attempt, and one was corrected by rolling but required surgery later because of an additional lesion. Percutaneous abdominal ultrasound was a valuable aid in the diagnosis of LDDLC and in confirming correction of the displacement after a nonsurgical rolling procedure.

Types of colic and frequency of postcolic abortion in pregnant mares: 105 cases (1984-1988).

The records of 105 pregnant mares and 105 nonpregnant horses with colic admitted to an equine hospital were reviewed. The 2 groups had similar types of colic and short-term survivability. Of the 105 pregnant mares, 31 were treated medically and 74 required surgical intervention. Thirty-three of the 105 mares died or were euthanatized. Thirteen (18%) of the 72 remaining mares aborted. Of 4 mares with severe medical cases, 2 died, 1 aborted, and 1 aborted and died. Of 27 horses with medical cases that required less intensive treatment, none died and 2 aborted. Of the 74 horses that required surgery, 45 survived to termination of pregnancy (foaling or abortion); 36 of these mares (80%) had a live foal. The type of surgical lesion had no effect on pregnancy outcome. Stage of gestation at initial examination, duration of anesthesia, or intraoperative hypoxia or hypotension had no effect on pregnancy outcome. However, when hypoxia occurred during colic surgery in the last 60 days of pregnancy, the mares either aborted or delivered severely compromised foals that did not survive.

Small-intestinal volvulus as a complication of acquired inguinal hernia in two horses.

Volvulus of the small intestine was diagnosed as a complication of acquired inguinal herniation in 2 horses. One of the horses continued to have signs of pain after reduction of the hernia. The volvulus was diagnosed at a second surgery, but the intestine was devitalized, and the horse was euthanatized. Ventral midline exploratory surgery was performed on the second horse, in conjunction with an inguinal approach. The small-intestinal volvulus was diagnosed and corrected at this time. It is suggested that ventral midline abdominal exploration be performed when acquired inguinal herniation causes acute small-intestinal obstruction in horses.

Cesarean section in 19 mares. Results and postoperative fertility.

The case records of 19 mares undergoing caudal ventral midline celiotomy for cesarean section were reviewed. Surgical exposure to the uterus was good, and the incisions healed by first intention in surviving mares. Seventeen mares (89%) survived to time of hospital discharge. Six foals (32%) were delivered alive, of which three were euthanatized because of severe deformity (1 died on day 6 and 2 survived to time of discharge). The most frequent postoperative complications were abdominal pain (13 mares), anemia (10 mares), and retained placenta (6 mares). Sixteen mares were bred during at least one season after the cesarean section and eight (50%) produced at least one foal. The collective foaling rate for these mares, bred a total of 25 seasons, was 36%. Only one mare bred during the same year as the surgery produced a live foal. The collective foaling rate for mares bred after the year of the surgery was 50%.

Monorchidism in three colts.

Three monorchid colts were admitted for castration as cryptorchids. Two colts each had one normal descended testis, and the third colt had a small testis in the abdomen. Monorchidism was diagnosed at surgery by locating an incomplete epididymis without a testis. After the incomplete epididymis and other testis were removed, the absence of testicular tissue was confirmed by results of a human chorionic gonadotropin response test.

Ovariectomy, ovariohysterectomy, and cesarean section in mares.

Ovariectomy and cesarean section are relatively common procedures in a surgical practice in an area in which there are numerous broodmares. Both techniques can be performed by several approaches, which are described in this article. Also described are techniques for ovariohysterectomy, a procedure that is rarely indicated, but that can be performed relatively easily by a capable surgeon.

Continuous absorbable suture pattern in the closure of ventral midline abdominal incisions in horses.

A retrospective study was performed to evaluate the healing of ventral midline abdominal incisions, closed with a simple continuous suture pattern using absorbable suture material, in 139 horses and foals. Dehiscence and incisional hernia developed separately in two horses. The low incidence of dehiscence and incisional hernia, compared with their reported incidence following the use of interrupted suture repair, leads the authors to recommend this alternative method of abdominal incision closure in horses. The security of closure is not sacrificed and the advantages of a rapid closure are desirable.