Evaluation of Internal Obturator Muscle Transposition in Treatment of Perineal Hernia in Dogs

A technique that utilizes transposition of the internal obturator muscle for repair of perineal hernias was evaluated. Forty-two male dogs were followed for at least one year after surgery. The repair failed in only one animal, a dog with previously operated bilateral hernias. Microangiography demonstrated an adequate blood supply to the transposed internal obturator muscles of two dogs examined at three weeks and three months after surgery.     

THE NON-CARDIAC DISTRIBUTION OF 99mTC-METHOXY-ISOBUTYL-ISONITRILE (SESTAMIBI) IN NORMAL BEAGLES

Technetium-99m methoxy-isobutyl-isonitrile (sestamibi) is a radiophartnaceutical used for the evaluation of myocardial perfusion. Increased uptake of sestamibi has also been documented in tumors. The objective of this study was to document the extracardiac biodistribution of ^99mTc sestamibi in the normal dog. Nine normal beagles were given 0.35 mCi/kg ^99mTc sestamibi intravenously, and 60 second images were made of the entire body at 1 hour post injection. A defined distribution pattern was recognized, with good visualization of the heart, liver, gallbladder, small intestine, kidneys, urinary bladder, popliteal lymph nodes, parotid salivary glands and zygomatic salivary glands. Splenic uptake was not seen.
Target to background ratios were calculated for all the regions listed, using background regions-of-interest with the smallest coefficient of variance for the denominator. The mean, range and standard deviation of these ratios are given.     

Wound Healing and Brain Stem Auditory Evoked Potentials After Experimental Total Ear Canal Ablation With Lateral Tympanic Bulla Osteotomy in Dogs

Experimental total ear canal ablation with lateral tympanic bulla osteotomy (TECA-LBO) was performed in 13 normal dogs to evaluate healing and retention of brain stem auditory evoked potentials (BSAEP) after surgery. Healing was evaluated by gross and microscopic examination of the surgery sites after 1 (n = 2), 4 (n = 8), 5 (n = 1), and 6 (n = 1) weeks. One dog was eliminated from the study. Brain stem auditory evoked potentials were measured using an air-conducted sound stimulus before and after surgery and before killing. Two dogs had nearly complete obliteration of the tympanic cavity by immature fibrous connective tissue. Eight dogs responded to surgery by either complete or partial re-formation of the tympanic cavity. Retention of the tympanic membrane in three dogs promoted re-formation of the tympanic cavity and blind epithelialized pockets in the surgery site with accumulation of keratinized debris. Granulation tissue formation and extensive proliferation of new bone on the internal surface of the tympanic bulla was seen in 10 dogs. Proliferative bone completely obliterated the tympanic cavity in two of these dogs. Eleven of 13 dogs had no detectable air-conducted BSAEP after surgery. There was no change in BSAEP measurements before killing compared with postoperative measurements in any dog. Two dogs with retained tympanic membranes had measurable BSAEP after surgery. This study shows that healing after TECA-LBO may be highly variable. Retention of the tympanic membrane and small osteotomies appeared to promote reformation of tympanic cavities and prevent ingrowth of granulation tissue. New bone proliferation was frequently observed in response to curettage of the epithelium lining the tympanic bulla. Hearing, as determined by BSAEP measurements, was lost except when the tympanic membrane and ossicles were retained. Retained tympanic membranes promoted accumulation of keratinized cellular debris that could become a nidus for infection or late abscessation in some dogs. These results indicate that resection of as much of the lateral and ventral tympanic bulla as possible and removal of the tympanic membrane may provide consistently improved results after TECA-LBO.     

Distribution of Topical Agents in the Frontal Sinuses and Nasal Cavity of Dogs: Comparison Between Current Protocols for Treatment of Nasal Aspergillosis and a New Noninvasive Technique

To document and compare patterns of distribution of topically applied antifungal medication, heads from 42 canine cadavers were assigned to seven treatment groups which included two current surgical treatment protocols for nasal aspergillosis, and a new, noninvasive method. Catheters (8 Fr) were placed through trephine holes into the frontal sinuses and nasal cavity. Dilute dye was injected through the catheters and the heads were sectioned sagittally. The administration of 5 mL of dye into the lateral frontal sinus and nasal cavity (group IA, 10 mL total) was compared with 25 mL injected through catheters placed bilaterally in the lateral frontal sinus and nasal cavity (group II, 100 mL total). Both were compared with the administration of 50 mL of dye through a catheter placed in the dorsal nasal meatus via each nostril (group III). The heads in group III had significantly ( P <.05) better dye distribution to all cavities than group IA and better distribution to the rostral frontal sinus than group II. Groups IV to VI were designed to show the pattern of distribution of dye to the contralateral nasal cavity and frontal sinuses. In all groups, dye injected into the lateral frontal sinus did not cross into the ipsilateral rostral frontal sinus or vice versa unless the transverse septum dividing the compartments had been penetrated during trephination.     

Distraction Osteogenesis Using Modified External Fixation Devices in Five Dogs

Distraction osteogenesis was used to treat five dogs with limb deformities or limb shortening. The affected bones underwent osteotomy, and modified external fixators were attached. Complications included pin loosening, implant breakage, and soft-tissue contracture. Adequate limb length was attained in all cases, but clinical results varied from poor to excellent. Two dogs were not lame after the procedure, two dogs had improved function but were still lame, and one dog had complications necessitating amputation.     

Hemodynamic Function during Neurectomy in Halothaneanesthetized Horses with or without Constant Dose Detomidine Infusion

Nine horses were premediated with acepromazine, and anesthesia was induced with guaifenesin and thiamylal. Anesthesia was maintained in four horses with halothane in oxygen, and in five horses with halothane in oxygen plus a constant dose infusion of detomidine. Both maintenance regimens produced a MAC equivalent of 1.4 at the ambient barometric pressure. Hemodynamic and respiratory measurements were made after the horses were anesthetized, during surgical manipulations involving skin or tissues other than nerves, during manipulation and transection of digital nerves, and after surgery while the limbs were being bandaged. Heart rate was significantly higher in horses anesthetized with halothane only than in horses that also received detomidine; there were no other differences in hemodynamic function or recovery characteristics. Respiratory rate was significantly higher than baseline during soft tissue and nerve manipulations; arterial blood pressure was significantly higher after surgery began and highest during neurectomy; cardiac output and cardiac index were significantly decreased during surgery; systemic vascular resistance was significantly increased during neurectomy and bandaging and highest during neurectomy. The data suggest that the increase in blood pressure often associated with surgical stimulation is caused by increased vascular resistance and may be accompanied by a decrease in cardiac output.     

ENLARGING BILATERAL FEMORAL CONDYLAR BONE CYSTS WITHOUT SCINTIGRAPHIC UPTAKE IN A YEARLING FOAL

Bilateral subchondral bone cysts of the femoral condyles were diagnosed by conventional radiography in a 14 month old Appaloosa colt. Surgical debridement was performed, and over the next 18 months the appearance of the cysts was evaluated with radiography and bone scintigraphy. On the preoperative scintigrams, increased radiopharmaceutical uptake was associated with the cysts. Despite continued radiographic enlargement, the cysts did not demonstrate increased radiopharmaceutical uptake post-operatively.