Use of a novel surgical approach for treatment of complete bilateral membranous choanal atresia in an alpaca cria.

CASE DESCRIPTION A 4-hour-old 6.3-kg (13.9-lb) female alpaca cria was evaluated because of severe respiratory distress and difficulty nursing since birth. CLINICAL FINDINGS The cria had open-mouth breathing and cyanotic membranes, with no airflow evident from either nostril. Supplemental oxygen was delivered, and the patient was anesthetized and intubated orotracheally; a CT evaluation of the head confirmed bilateral membranous obstruction of the nasal cavities, consistent with complete bilateral choanal atresia. TREATMENT AND OUTCOME Choanal atresia was treated with an endoscopically assisted balloon-dilation technique, and temporary tracheostomy was performed. Stenosis recurred, requiring revision of the repair and intranasal stent placement 3 days after the first surgery. The tracheostomy tube was removed the next day. Complications during hospitalization included mucoid obstruction of the tracheostomy tube, granulation tissue development in the trachea near the tracheostomy site, mucoid stent obstruction, aspiration pneumonia, and presumed partial failure of passive transfer of immunity. The stents were removed 2 weeks after admission, and the cria was discharged 3 days later. The owner was advised that the animal should not be bred. At last follow-up 3 years later, the alpaca was doing well. CLINICAL RELEVANCE Surgical treatment with a balloon-dilation technique and placement of nasal stents with endoscopic guidance were curative in this neonatal alpaca with bilateral membranous choanal atresia. Computed tomography was useful to determine the nature of the atresia and aid surgical planning. Because a genetic component is likely, owners should be advised to prevent affected animals from breeding.

Short-term effect of ovariectomy on measures of insulin sensitivity and response to dexamethasone administration in horses.

OBJECTIVE: To evaluate the effect of ovariectomy on insulin sensitivity in horses and determine whether the effects of suppression of the hypothalamo-pituitary-adrenal axis differ before and after ovariectomy. ANIMALS: 6 healthy mares. PROCEDURES: The horses underwent an IV glucose tolerance test (IVGTT), an insulin sensitivity test, and a dexamethasone suppression test before and 5 weeks after ovariectomy. Body weight, serum cortisol and plasma ACTH concentrations, serum insulin-to-blood glucose concentration ratios, and changes in blood glucose concentration with time after injection of glucose or insulin were compared before and after ovariectomy. RESULTS: The dexamethasone injection resulted in a decrease in serum cortisol concentration before and after ovariectomy. In all horses, baseline plasma ACTH concentrations were within the reference range before and after ovariectomy. For each mare, results of an IVGTT before and after ovariectomy were considered normal. No significant differences in basal blood glucose concentration or time to reach baseline glucose concentration after an IVGTT were observed. Basal serum insulin concentration and serum insulin-to-blood glucose concentration ratios were not significantly different before or after ovariectomy, nor was the mean time to attain a 50% decrease in blood glucose concentration after insulin injection. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that ovariectomy does not appear to modify dexamethasone response in horses and that it does not modify short-term measures of insulin sensitivity. Findings suggested that horses undergoing ovariectomy are not at higher risk of developing equine metabolic syndrome or hypothalamo-pituitary-adrenal axis dysfunction and associated morbidity.

Comparison of transvaginal natural orifice transluminal endoscopic surgery (NOTES®) and laparoscopy for elective bilateral ovariectomy in standing mares.

OBJECTIVE: To compare surgical trauma, perioperative pain, surgical time, and complication rate in mares undergoing standing bilateral ovariectomy by natural orifice transluminal endoscopic surgery (NOTES) or laparoscopy. STUDY DESIGN: Experimental study. ANIMALS: Healthy mares (n = 12). METHODS: Ovariectomy was performed with a vessel-sealing device by transvaginal NOTES (n = 6) using a flexible endoscope and specialized instruments or by bilateral flank laparoscopy (n = 6). Preoperative and postoperative complete blood count (CBC), plasma fibrinogen concentration, serum amyloid A concentration, peritoneal nucleated cell count, and total protein concentration were compared using repeated measures ANOVA. Surgical times were compared using an unpaired t-test. Mares were monitored for 2 weeks postoperatively and necropsy was performed at 3 weeks (n = 6) or 3 months (n = 6) to assess short- and medium-term effects of each procedure. Complication rate, necropsy, and bacteriology findings were compared using a Fishers exact test. Significance was set at P < .05. RESULTS: All surgical procedures were performed successfully and all but one laparoscopy mare were bright, alert, and maintained a good appetite until euthanasia. Mean ± SD surgical time was similar between groups (NOTES: 100 ± 40 minutes; laparoscopy: 107 ± 47 minutes). There were no significant temporal differences in vital parameters, CBC, plasma fibrinogen concentration, serum amyloid A concentration, peritoneal nucleated cell count, and total protein concentration between groups. CONCLUSIONS: Bilateral ovariectomy by transvaginal NOTES or laparoscopy resulted in minimal inflammation and surgical trauma.

Standing ovariectomy in mares using a transvaginal natural orifice transluminal endoscopic surgery (NOTES®) approach.

OBJECTIVE: To develop and assess the feasibility of standing transvaginal Natural Orifice Transluminal Endoscopic Surgery (NOTES®) ovariectomy in the mare. STUDY DESIGN: Descriptive study. ANIMALS: Mares (n=10). METHODS: The technique was developed in 6 mares and then evaluated in a short-term study in 4 mares. Abdominal access was developed using controlled access vaginal cannula placement under endoscopic guidance. With viewing provided by a flexible endoscope, hemostasis, and transection of ovarian pedicles was performed using a customized bipolar vessel-sealing device. The ovaries were retrieved and the colpotomy was sutured. Surgical time, intra-, and postoperative complications were recorded. Necropsy was performed immediately after surgery in 6 mares and 15 days after surgery in 4 mares to assess short-term complications. RESULTS: After the instruments and techniques were developed, transvaginal NOTES® ovariectomy was successfully performed. Analgesia during the procedure was adequate in all cases. The visual field provided by the endoscope was acceptable. The customized 60 cm vessel-sealing device provided good hemostasis and a comfortable working length. Intraoperative complications included difficult viewing that prolonged operative time and inability to remove the second ovary in 1 mare. Postoperative recovery was excellent. Postmortem findings of 1 true positive microbial culture, elevated cell counts in abdominal fluid, and adhesion formation raise questions that must be addressed in future studies. CONCLUSION: Using specialized instruments, transvaginal NOTES® ovariectomy is technically feasible in mares.