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Biomedical subjects

M A Livesey

Publications and source records attributed to M A Livesey.

13 recordsLinked to original sources

Postcastration eventration in 18 horses: the prognostic indicators for long-term survival (1985-1995).

Castration of horses is considered a common and routine surgical procedure, but the potential for complications is high. By far the most serious of these is eventration. The objectives of this study were to determine the long-term survival of horses undergoing surgical treatment of indirect (1) inguinal eventration of the small intestine following castration, and to identify prognostic indicators for survival. The case records of 18 horses undergoing surgical treatment of postcastration eventration (PCE) between 1985 and 1995 were reviewed. Follow-up information was obtained by telephone interviews 2 to 13 y postoperatively. A Cox proportional hazard regression model was fitted to determine which clinical features were of significant influence to survival. Clinical features with a significant negative influence on survival were an inguinal surgical approach for correction, an increased length of prolapsed bowel, and performance of bowel resection and anastomosis. Significant postoperative complications developed in 89% of cases; 44% of cases in the "inguinal" surgical approach group developed peritonitis, compared with 10% in the "midline" approach group. Of all horses in this study, 72% were discharged from the hospital; however, only 40% of horses in the inguinal approach group were discharged. The long term survival rate (> 1 y) for all horses in this study was 44%, with a median survival time of 3-1/2 mo.

Animals↗

Evaluation of exploratory laparotomy in young horses: 102 cases (1987-1992).

OBJECTIVE: To determine, in a population of young horses, whether a variation exists among neonates, sucklings, weanlings, and yearlings regarding recovery from anesthesia, short- and long-term survival rates, and postoperative adhesion formation following exploratory laparotomy. DESIGN: Retrospective study. ANIMALS: 102 horses < 25 months old that underwent exploratory laparotomy. PROCEDURE: Pre-, intra-, and postoperative information was retrieved from medical records, conversations with referring veterinarians, owners, or trainers, and race records. Survival rates (recovery from anesthesia and short- and long-term survival) were compared with age, lesion type, lesion location, surgical procedure, and development of clinically important postoperative intestinal adhesions. RESULTS: Of the 73 horses that recovered from anesthesia, 69 were available for follow-up. Of the 69 horses, 7 (10%) died of complications associated with formation of intestinal adhesions. Age did not affect incidence of adhesion formation, lesion type, lesion location, or surgical procedure performed. Long-term survival rate after surgery for correction of a small-intestinal lesion was 34%, whereas that after surgery for correction of a large-intestinal lesion was 65%. CLINICAL IMPLICATIONS: Surgical treatment of colic in young horses resulted in survival rates that are similar to those reported for mature horses. The incidence of clinically important postoperative adhesions was greater than that found for young horses in earlier studies. This may be the result of the younger age of our study population. Alternatively, improvements in operative techniques and postoperative management may allow a larger percentage of horses to survive long term and develop complications such as adhesion formation.

Anesthesia↗

Multiple aneurysmal bone cysts in a foal.

Multiple aneurysmal bone cysts (ABCs) are previously unreported in horses. An ABC was diagnosed in the left 3rd metacarpal of a Thoroughbred foal, which partially resolved following surgical curettage. A 2nd ABC developed in the left tibia, 7 wk postoperatively, and the foal was euthanized.

Animals↗

Development of a laboratory animal model of postoperative small intestinal adhesion formation in the rabbit.

In order to establish a model of postoperative intestinal adhesions that would simulate the problem experienced in horses, New Zealand White rabbits were utilized to compare two models of adhesion formation that had been successful in the horse, an ischemic strangulating obstruction (ISO) model and a serosal scarification model. An untreated control group was compared with animals subjected to 1, 2, 3 and 4 h periods of ISO, and to serosal scarification. At postmortem examination 14 d postoperatively, the number of rabbits in each group with adhesions was recorded. Serosal scarification was significantly more consistent at producing adhesions than ISO (Fisher's exact test, P = 0.0022). The 3 h of ISO group was significantly different from the control group: however, compared to the serosal scarification group, fewer animals had adhesions and one animal died of complications associated with the experimental procedure. Based on these results, serosal scarification was selected as the best model for utilization in further studies of adhesion prevention.

Animals↗

Utilization of the serosal scarification model of postoperative intestinal adhesion formation to investigate potential adhesion-preventing substances in the rabbit.

A rabbit serosal scarification model was utilized to compare the ability of four drugs, previously administered peri-operatively to horses undergoing exploratory celiotomy, to prevent the development of postoperative intestinal adhesions. The substances compared were 32% Dextran 70 (7 mL/kg), 1% sodium carboxymethylcellulose (7 mL/kg), trimethoprim-sulfadiazine (30 mg/kg), and flunixin meglumine (1 mg/kg). The first two were administered intra-abdominally following surgery, while the latter two were administered systemically in the peri-operative period. Fibrous adhesions were evident in all animals in the untreated serosal scarification group. No significant difference in the number of animals with adhesions was found between the untreated control group and any treatment group, nor among the treatment groups. Microscopic examination of adhesions collected at postmortem examination revealed fibers consistent with cotton, surrounded by a giant-cell reaction and ongoing acute inflammation. The source of the fibers was likely the cotton laparotomy sponges used to scarify the intestinal surface, since the pattern in the granuloma and sponge fibers appeared similar under polarized light. Though consistent intestinal adhesion formation was produced in the rabbit, the presence of foreign body granulomas may prevent consideration of this model for future research. The drugs tested were ineffective in preventing the formation of postoperative small intestinal adhesions in this model.

Animals↗

Ethmoid adenocarcinoma perforating the cribriform plate in the horse.

This clinical report describes an 8-year-old Thoroughbred mare that was presented for evaluation of a chronic, unilateral nasal discharge. Findings on physical examination, radiology, and video-endoscopy supported a clinical diagnosis of ethmoidal hematoma. After surgical ablation of the mass a defect was detected in the cribriform plate. At necropsy a 1.5 cm aperture was identified in the left cribriform plate allowing direct communication between the fundus of the nasal cavity and the cranium. Histology of the mass identified tissue consistent with an adenocarcinoma. History of profuse epistaxis warrants further investigation to differentiate malignant lesions from the more common benign lesions. During surgical ablation of large, space-occupying masses of the caudodorsal nasal cavity the cribriform plate should be examined for defects or secondary erosive lesions.

Adenocarcinoma↗

Factors affecting incisional complication rates associated with colic surgery in horses: 78 cases (1983-1985).

From May 1, 1983 to April 1, 1985, 142 operations were performed on horses with signs of acute abdominal pain (colic), using a ventral midline incision. Seventy-eight horses lived for at least 15 days after surgery or had acute dehiscence and were included in the study. Seventy horses had surgery once, and 8 horses had surgery 2 or more times. Six-month follow-up evaluation was obtained for 66 horses that had 1 surgery and for 6 horses that had multiple surgeries. Incisional complications included drainage (including infection), acute dehiscence, hernia, and suture sinus formation. The effects of preoperative peritoneal fluid presence, enterotomy or resection, suture material and pattern used in the linea alba, type of skin closure and use of a sutured-on stent bandage on the incidence of incisional complications were investigated. The complication of incisional infection rate associated with a near-far-far-near suture pattern vs simple interrupted pattern in the linea alba was the only statistically significant (P less than 0.05) difference observed.

Animals↗

Congenital malformation of the large colon causing colic in a horse.

An abnormal mesocolic attachment which resulted in a stellate malformation of the left colon adjacent to the pelvic flexure was suspected to be the cause of intermittent episodes of colic in a horse. Resection and side-to-side anastomosis of the large colon at the level of the sternal and diaphragmatic flexures was performed and the horse made an uneventful recovery from surgery. Only minor serum biochemical changes were observed in the initial postoperative period. The abnormal mesocolic attachment was probably a congenital anomaly.

Animals↗