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Biomedical subjects

D E Slone

Publications and source records attributed to D E Slone.

At least 19 recordsLinked to original sources

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.

Age Factors↗

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.

Animals↗

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.

Animals↗

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.

Anastomosis, Surgical↗

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.

Abscess↗

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).

Animals↗

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.

Abdominal Pain↗

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.

Abortion, Veterinary↗

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.

Animals↗

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.

Animals↗

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.

Animals↗

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.

Abdomen↗

Traumatic tarsal luxation repaired without internal fixation in three horses and three ponies.

Three horses and three ponies were treated for traumatic luxation of the proximal intertarsal or tarsometatarsal joint. In each case, there were fractures of one or more tarsal bones. Three of the animals had disruption of one of the collateral ligaments. Five animals were treated by closed reduction and external coaptation. One pony was treated by open curettage, a cancellous bone graft, and cast immobilization. No internal fixation was used in any of these animals. From this series of cases, it would appear that closed reduction and external coaption alone is adequate treatment for most cases of tarsal luxation.

Animals↗

Gastroenterostomy for treatment of gastroduodenal ulcer disease in 14 foals.

Gastroenterostomy was performed in 14 foals to treat gastric outflow obstruction caused by advanced gastroduodenal ulcer disease. The onset of excessive salivation and teeth grinding, without response to medical treatment, combined with endoscopic and radiographic evidence of gastric outflow obstruction, were indications for surgical intervention. Successful outcome in 5 foals was attributed to early diagnosis, patient stabilization, early surgical correction, and postoperative management including antibiotics and antiulcer medication.

Animals↗

Cortisol (hydrocortisone) disappearance rate and pathophysiologic changes after bilateral adrenalectomy in equids.

Six ponies and 1 horse were bilaterally adrenalectomized (BADX). The survival time of 2 of the 7 animals after BADX was 24 and 72 hours without supplemental corticosteroids. The cause of death was not related to the surgical technique. The biological half-life of cortisol (hydrocortisone) was estimated to be 2.1 +/- 0.6 hours. The disappearance of cortisol in the horse was found to be biphasic, composed of redistribution and elimination phases. Pathophysiologic changes (ie, increased serum sodium and chloride, increased PCV, and decreased serum potassium) similar to those seen in other species after BADX were found. Clearance of electrolytes was calculated, using the creatinine clearance method. These values were inversely correlated with the changes seen in serum electrolytes.

Adrenalectomy↗

Sodium retention and cortisol (hydrocortisone) suppression caused by dexamethasone and triamcinolone in equids.

Three ponies and 1 horse were bilaterally adrenalectomized (BADX). The initial hypoadrenal episode after BADX was reversed with 20 mg of dexamethasone (DXM) IM (n = 2) or 20 mg of triamcinolone (TMC) IM (n = 2). Nine hypoadrenal crises were reversed with 20 mg of DXM given IM (n = 4) or 20 mg of TMC given IM (n = 5). Sodium and chloride retention and potassium excretion were documented based on changes in serum electrolytes and urinary excretion. Eight intact adult horses were randomly assigned to 2 groups to study the effects of a single IM injection of DXM (0.044 mg/kg of body weight) or TMC (0.044 mg/kg). Cortisol (hydrocortisone) suppression was found to be maximal (nondetectable amounts of cortisol) by 12 hours in both groups. Cortisol was again detectable in the DXM group at 24 hours after injection and was at pretreatment values at 168 hours. Cortisol was not detectable in the TMC group for 192 hours and did not reach pretreatment values until 336 hours. The duration of the gluconeogenic effect was compared with the duration of cortisol suppression exerted by DXM and TMC in these intact animals. Assuming that the decrease in plasma glucose coincides with the decrease in glucocorticoid activity of the respective steroid, a relative hypoadrenocortical state was found in the animals treated with DXM between the 2nd and 7th day after treatment, whereas this state occurred between the 6th and 14th day after treatment with TMC.

Adrenalectomy↗

Noniatrogenic rectal tears in three horses.

Rectal tears were detected in three horses treated for colic. Based on historical, clinical, and postmortem findings, the tears could not be attributed to the attending veterinarian and were therefore not iatrogenic (physician induced). One tear was attributable to an infarction that presumably resulted from thromboembolism; 1 tear occurred without any evidence of external cause and resulted in such severe peritonitis that the cause and resulted in such severe peritonitis that the cause could not be determined, and 1 tear occurred during rectal palpation by the owner, before he called the veterinarian. Postmortem examination of the last horse revealed lesions suggestive of thromboembolism. It was concluded that thromboembolism may have caused or predisposed to two of the rectal tears and could not be ruled out in the third.

Animals↗