bluuebunny/crossref_metadata_2025 huggingface dataset:
Occlusion of the External Carotid and Maxillary Arteries in the Horse to Prevent Hemorrhage from Guttural Pouch Mycosis
Authors: FREEMAN DAVID E. , ROSS MICHAEL W. , DONAWICK WILLIAM J. , HAMIR AMIRALI N.
Published: February 2008

Balloon‐tipped catheters were used to occlude the external carotid artery and its branches in nine horses with hemorrhage caused by guttural pouch mycosis. The internal carotid artery on the affected side was occluded simultaneously in four horses and had been occluded previously in two others. In three horses, a single balloon‐tipped catheter was inserted in the external carotid artery beneath the floor of the guttural pouch and its tip was advanced blindly into distal branches. In one horse, the superficial temporal artery was occluded briefly during surgery by a balloon‐tipped catheter so a catheter inserted into the external carotid artery could be diverted into the maxillary artery. In the other five horses, the external carotid artery was occluded proximally and the maxillary artery was occluded immediately caudal to the alar canal by a balloon‐tipped catheter inserted into the major palatine artery. Serious postoperative hemorrhage did not occur in eight horses, but one horse that had a single balloon‐tipped catheter inserted into the external carotid artery had profuse hemorrhage 11 days after surgery and was euthanatized. One horse was euthanatized because of persistent dysphagia. The only complication related to use of balloon catheters was a mild incisional infection in one horse. It was concluded that the external carotid and maxillary arteries must be occluded on both sides of the eroded segment to prevent hemorrhage from normograde and retrograde flow.
A Preliminary Comparison of Lidocaine and Xylazine as Epidural Analgesics in Ponies
Authors: FIKES L. W. , LIN H. C. , THURMON J. C.
Published: February 2008

Xylazine (0.35 mg/kg) or lidocaine (0.35 mg/kg) was injected into the epidural space of six ponies to compare their effectiveness as epidural analgesics. Each pony received both treatments at 1 week intervals with the order of treatments randomized. Xylazine produced analgesia of significantly longer duration (247 ± 58 minutes) than that produced by an equal dose of lidocaine (135 ± 22 minutes). Mild transient ataxia of no clinical significance developed in all ponies with both treatments. Spinal cords were removed from two ponies and examined histologically. No discernible pathologic changes were noted.
Vascular Anatomy of the Descending Colon of the Horse
Authors: BEARD W. L. , LOHSE C. L. , ROBERTSON J. T.
Published: February 2008

The blood supply to the descending colon of the horse was studied by gross dissection and methyl methacrylate corrosion casts. The arterial supply is derived from the left colic artery and cranial rectal artery with the left colic artery supplying approximately the proximal three fourths. Each artery gives off four to eight arcuate arteries that form a series of anastomosing arcades. The arcade pattern continues to form a marginal artery that parallels the long axis of the colon. Small branches from the marginal artery anastomose with adjacent branches to form a secondary arcade. The secondary arcade lies approximately 1 cm proximal to the mesenteric teniae and sends off long arteries at regular intervals that course circumferentially around the bowel. The long arteries begin under the serosal mesothelium and perforate the muscular layers to course in the submucosal layer. The long arteries branch off supplying the wall of the colon and arborize over the antimesenteric surface, anastomosing with the vessels from the opposite side. The result is the formation of a series of vascular rings surrounding the colon. Venous return, in general, parallels the arterial supply.
A Comparison of Methods for Proximal Palmar Metacarpal Analgesia in Horses
Authors: FORD TROY S. , ROSS MICHAEL W. , ORSINI PAUL G.
Published: February 2008

Three techniques for inducing analgesia of the proximal metacarpal region were evaluated for the frequency of inadvertent injection into the middle carpal and carpometacarpal joints. Using methylene blue solution as a marker dye and 30 fresh cadaver specimens each, three clinicians performed either 30 infiltrations at the origin of the suspensory ligament (method A), 30 palmar and palmar metacarpal nerve blocks at the proximal end of the metacarpus (method B), or 30 palmar and palmar metacarpal nerve blocks at the distal aspect of the accessory carpal bone (method C). The frequency of inadvertent injection into the distal carpal joints was 37, 17, and 0% for methods A, B, and C, respectively. The association between method and injection into the joints was significant (p < 0.01). Infiltration of the distal carpal joints occurred with injection distances from the carpometacarpal joint of 1.5 to 4.5 cm. Although there was no joint injection with method C, the carpal synovial sheath was inadvertently infiltrated in 68% of the specimens. Injection into the distal carpal joints can occur when deep injections are made into the proximal palmar aspect of the metacarpus because of the distopalmar outpouchings of the carpometacarpal joint between the axial surfaces of the second and fourth metacarpal bones and the abaxial surface of the suspensory ligament.
Osteochondral Fragments within the Dorsal Pouch or Dorsal Joint Capsule of the Proximal Intertarsal Joint of the Horse
Authors: STEPHENS P. R. , RICHARDSON D. W. , ROSS M. W. , FORD T. S.
Published: February 2008

The anatomy of the dorsal pouch of the proximal intertarsal joint (PIJ) and its communication with the tarsocrural joint (TCJ) was studied in 15 pairs of hocks from young and mature horses. The mediolateral length of the TCJ–PIJ fenestration was 14 to 29 mm. The potential volume of the dorsal pouch of the PIJ was 3 to 5 ml, and a recess extended 10 to 28 mm medial to the medial commissure of the TCJ–PIJ fenestration. In a correlated clinical study, osteochondral fragments were identified radiographically within the dorsal pouch (category 1) or dorsal joint capsule (category 2) of the PIJ in 17 horses undergoing arthroscopic surgery of the TCJ. In six horses with category 1 lesions, osteochondral fragments were found free within the dorsal pouch and were removed. In five horses, category 1 fragments were not located. All 11 horses were reported by owners to be sound after surgery. In seven horses, a minimally displaced fragment was identified at the distal aspect of the medial trochlear ridge, within the insertion of the synovium separating TCJ and PIJ (one horse had both types of lesions in the same hock). Five of the seven category 2 fragments were removed at surgery. Of the seven horses with category 2 lesions, four were training or racing, two were unsound, and one was still convalescing at the time of follow‐up.
Cardiorespiratory Effects of the Intravenous Administration of Tiletamine‐Zolazepam to Dogs
Authors: HELLYER PETER , MUIR WILLIAM W. , HUBBELL JOHN A. E. , SALLY JAN
Published: February 2008

The anesthetic, hemodynamic, and respiratory effects of an intravenously administered 1:1 combination of tiletamine and zolazepam were evaluated in dogs. Each dog received tiletamine‐zolazepam (6.6, 13.2, 19.8 mg/kg) on two occasions, once when awake and a second time with residual isoflurane anesthesia while instrumented for the recording of hemodynamic data. Tiletamine‐zolazepam administered to conscious dogs resulted in good, rapid induction of anesthesia. Time to sternal recumbency (recovery) was dose‐dependent. Character of recovery tended to be better with the lower dose. Tiletamine‐zolazepam caused significant increases in heart rate after all doses and significant increases in cardiac output after the two larger doses. All doses caused significant decreases in arterial blood pressure at 1 minute. Arterial blood pressures returned to baseline and then increased significantly above baseline values. The rate of development of left ventricular pressure was significantly decreased 1 minute after the two higher doses, returned to normal, and then was significantly increased above baseline for all doses. Peripheral vascular resistance increased transiently 1 minute after the 6.6 mg/kg dose. Peripheral vascular resistance decreased significantly after the 13.2 and 19.8 mg/kg doses. Minute ventilation was significantly decreased only after the 19.8 mg/kg dose.
Clinical Evaluation of Three Surgical Methods for Treatment of Caudal Cervical Spondylomyelopathy of Dogs
Authors: BRUECKER KENNETH A. , SEIM HOWARD B. , WITHROW STEPHEN J.
Published: February 2008

Sixty‐four dogs with caudal cervical spondylomyelopathy (CCSM) caused by chronic degenerative disc disease were treated with ventral decompression (n = 20), linear traction and interbody screw stabilization (n = 7), or linear traction and plastic plate stabilization (n = 37). Interbody screw stabilization was ineffective in treating CCSM because of an unacceptably high rate of implant failures. Ventral decompression or linear traction and plastic plate stabilization were effective in the treatment of most patients with mild to moderate neurologic deficits (neck pain, paraparesis, or ambulatory tetraparesis). Although these techniques were also used successfully in some patients with severe neurologic deficits (weakly ambulatory tetraparesis or nonambulatory tetraparesis), variable success rates and prolonged postoperative recovery periods were noted.
Reactivity of Equine Palmar Digital Arteries and Veins to Vasodilating Agents
Authors: BAXTER GARY M. , TACKETT RANDALL L. , MOORE JAMES N.
Published: February 2008

Palmar digital arteries and veins removed surgically from healthy horses under general anesthesia were cut into 4 mm vascular rings, suspended in tissue baths, and attached to force displacement transducers for continuous measurement of vascular tension. In vitro vascular responses were determined for acetylcholine, acepromazine, isoxsuprine hydrochloride (isoxsuprine), prostaglandin E2 (PGE2), and prostaglandin I2 (prostacyclin). After preconstriction with norepinephrine hydrochloride (norepinephrine), or prostaglandin F2 alpha (PGF2 alpha), the concentrations needed to produce 50% maximum relaxation (EC50) and the maximum percentage of relaxation were determined for each drug.

Acetylcholine was the most potent arterial vasodilator (smallest EC50 value) and PGE2 was the least potent. Prostacyclin was the least potent venodilator (highest EC50 value); there were no differences between acetylcholine, acepromazine, isoxsuprine, and PGE2. Isoxsuprine produced greater arterial relaxation than all other agents. Isoxsuprine and acepromazine produced significantly greater venous relaxation than did acetylcholine and PGE2. Prostacyclin produced minimal vasodilation of arteries or veins. Acepromazine and isoxsuprine relaxed the veins significantly more than the arteries. When PGF2 alpha was used instead of norepinephrine to preconstrict the arteries and veins, the potency and effectiveness of acepromazine and isoxsuprine to produce vasodilation were significantly decreased. Results indicate that acepromazine and isoxsuprine can relax the equine digital vasculature but their effectiveness varies depending on the origin of the constriction.
Knot Security of Suture Materials
Authors: ROSIN EBERHARD , ROBINSON GAIL M.
Published: February 2008

The knot security of chromic gut, polyglycolic acid, polyglactin 910, polydioxanone, polypropylene, and monofilament nylon size 2–0 suture materials were tested biomechanically in vitro. Twenty reproducible knots were tied and incubated in canine serum at 37° for 24 hours before testing. A “secure knot” was defined as a knot that, when tested to failure, broke rather than untied by slippage. The minimum number of throws necessary to make a secure, snug (1500 g tension) square knot was three for gut, polyglycolic acid, polyglactin 910, and polypropylene and four for polydioxanone and nylon. All throws including the first were counted. With all suture materials tested, surgeon's knots were as secure as square knots. Only gut, polyglycolic acid, and polydioxanone granny knots were as secure as square knots; no loosely tied (500 g tension) asymmetric square knots were as secure as snug square knots, and only polydioxanone and polypropylene loose square knots were as secure as snug square knots. Square knots used to start a continuous pattern required one additional throw with gut, polydioxanone, and nylon. Square knots used to end a continuous pattern required two to three additional throws with all materials tested.
Transcatheter Thoracic Duct Embolization in the Dog An Experimental Study
Authors: PARDO ANTHONY D. , BRIGHT RONALD M. , WALKER MICHAEL A. , PATTON CLARK S.
Published: February 2008

Thoracic duct embolization was created by injecting an isobutyl 2‐cyanoacrylate/iophendylate (IBCA) mixture through a cannulated mesenteric lymphatic vessel in eight normal dogs. Aqueous contrast lymphangiography was repeated at minute 10 and week 6. Six dogs were euthanatized at week 6 and two dogs at month 6. Embolization with 1.5 to 3.9 ml of the mixture resulted in complete obstruction of the thoracic duct in all eight dogs. Results of lymphangiography in six dogs at week 6 showed a persistent, complete obstruction of the thoracic duct in six dogs and alternate lymphaticovenous anastomoses in four dogs. Histologically, there were a sclerosing granulomatous response surrounding the lymphatic embolus, mild congestive changes in the mesenteric lymph nodes, and mild lacteal dilatation in the jejunum. The procedure was well tolerated with only a few complications. One dog suffered partial thrombosis of the cranial vena cava by the injected material with later dislodgement and embolization of a pulmonary artery branch. Modifications have been made in the injection procedure to avoid this complication. This technique for occlusion of the thoracic duct shows potential for clinical use in the management of canine chylothorax. The obstruction appears to be complete and permanent, and surgical/anesthetic time is decreased greatly from previously described procedures.
Incisional Hernias in the Horse Incidence and Predisposing Factors
Authors: GIBSON KATHERINE T. , CURTIS CHARLES R. , TURNER A. SIMON , McIlwraith C. WAYNE , AANES WILBUR A. , STASHAK TED S.
Published: February 2008

Medical records of 210 horses that survived ventral midline celiotomy for at least 4 months were examined and owners were queried to determine factors contributing to incisional hernia formation. The incidence rate of incisional hernias within 4 months was 16%. Factors significantly associated with occurrence of incisional hernias were incisional drainage, closure of the linea alba with chromic gut suture material, previous midline celiotomy, excessive incisional edema, castrated male sex, postoperative leukopenia, and postoperative pain (colic). Factors not significantly associated with occurrence of incisional hernias were suture pattern used for linea alba closure, concurrent enterotomy or intestinal resection, postoperative bandage or stent, postoperative fever, hypoproteinemia, diarrhea, respiratory disease (coughing), and peritonitis. Hernias developed in horses within 12 weeks of surgery, with the earliest hernia recognized at week 2. Of 30 horses for which information was available, only one hernia developed in 24 (80%) and two or more hernias developed in 6 (20%) along the incision. Multiple hernias tended to be smaller than single hernias.
Hiatal Hernia Repair by Restoration and Stabilization of Normal Anatomy An Evaluation in Four Dogs and One Cat
Authors: PRYMAK CAROLINE , SAUNDERS H. MARK , WASHABAU ROBERT J.
Published: February 2008

Clinical signs of esophageal hiatal hernia in four dogs and one cat included regurgitation, vomiting, hematemesis, hypersalivation, dysphagia, and dyspnea. Thoracic radiographs, esophagram, and fluoroscopy were used to demonstrate cranial displacement of the esophagogastric junction and part of the stomach through the esophageal hiatus. Other findings included megaesophagus, esophageal hypomotility, gastroesophageal reflux, and pneumonia. Medical therapy failed to resolve the clinical signs. Reduction in size of the esophageal hiatus, fixation of the esophagus to the diaphragmatic crus (esophagopexy), and a left fundic gastro‐pexy were performed. Surgical results were considered good to excellent.
Occurrence of Problems after Three Techniques of Bilateral Thyroidectomy in Cats
Authors: WELCHES CARLA D. , SCAVELLI THOMAS D. , MATTHIESEN DAVID T. , PETERSON MARK E.
Published: February 2008

Bilateral thyroidectomy was performed in 106 cats with hyperthyroidism by one of three techniques: original intracapsular, modified intracapsular, or modified extracapsular. Hypocalcemia was detected in the first 3 days after surgery in 11 (22%) of 50 cats treated by the intracapsular technique, 10 (33%) of 30 cats treated by the modified intracapsular technique, and 6 (23%) of 26 cats treated by the modified extracapsular technique. Hypocalcemia was classified as mild or severe. No signs of hypoparathyroidism developed in any of the 13 cats with mild hypocalcemia. Of the 14 cats with severe hypocalcemia, 8 had clinical signs of hypoparathyroidism before and during treatment with calcium and vitamin D, 3 were treated and no clinical signs developed, 2 were not treated but no clinical signs developed, and 1 was lost to follow‐up. No cat required permanent calcium or vitamin D supplementation after surgery. Severe hypocalcemia and clinical signs of hypoparathyroidism occurred in 3 (6%) of the 50 cats treated by the intracapsular technique, 4 (13.3%) of the 30 cats treated by the modified intracapsular technique, and 1 (3.8%) of the 26 cats treated by the modified extracapsular technique. Twelve cats had recurrence of hyperthyroidism at a median time of 23 months. The intracapsular technique was used in 11 of these cats, and the modified extracapsular technique was used in 1. No clinical signs of hypothyroidism were detected in any of the cats. The modified intracapsular and modified extracapsular techniques of bilateral thyroidectomy are effective procedures for the treatment of feline hyperthyroidism.
Esophageal Disorders in 61 Horses: Results of Nonsurgical and Surgical Management
Authors: CRAIG D. R. , SHIVY D. R. , PANKOWSKI R. L. , ERB H. N.
Published: February 2008

Obstructive esophageal disorders in 61 horses included feed or foreign body impaction (27 horses), strictures (18 horses), perforations (11 horses), and diverticula (5 horses). Horses with feed impaction were treated nonsurgically (25 horses) or by esophagotomy (2 horses). Survival to discharge was 78%, and 37% of these had persistent chronic obstruction at home. Long‐term survival was 52%. Long‐term survival of nine horses treated nonsurgically for esophageal strictures was 22%; for nine horses treated surgically it was 44%. Long‐term survival of horses treated nonsurgically was significantly better in acute than chronic strictures. Surgical repair of esophageal mural strictures was more successful than repair of annular or mucosal strictures. One third of the horses with strictures were foals. Long‐term survival for horses with strictures was 33%. Long‐term survival was higher for the horses with perforations managed surgically (2 of 4) than nonsurgically (0 of 7). Long‐term survival for this group was 18%. One esophageal diverticulum was managed nonsurgically, and four were treated surgically; all horses survived long term. Complications of obstructive esophageal disorders included aspiration pneumonia, chronic obstruction, esophageal mucosal ulceration, postoperative infection, pleuritis, laminitis, laryngeal paralysis, and Horner's syndrome.
Ventral Rhinotomy in the Dog and Cat
Authors: HOLMBERG DAVID L. , FRIES C. , COCKSHUTT J. , PELT D. VAN
Published: February 2008

The nasal cavities of 14 dogs and three cats were explored surgically using a ventral rhinotomy. The exposure achieved through this approach was considered to be equal to a dorsal rhinotomy. One animal died during the immediate postoperative period from perforation of a gastric ulcer. The other animals recovered well and had no significant complications. The long‐term survival of the animals was consistent with previous reports for their diseases. Ventral rhinotomy is no more difficult than dorsal rhinotomy, has less patient morbidity and fewer postoperative complications, and is more cosmetically acceptable.
Production of Patellar Lesions by Medial Patellar Desmotomy in Normal Horses
Authors: GIBSON KATHERINE T. , MCLLWRAITH C. WAYNE , PARK RICHARD D. , NORRDIN ROBERT W.
Published: February 2008

Medial patellar desmotomy was performed on one (treated) hindlimb, and a sham operation on the other (control) hindlimb, of 12 normal horses. The horses were examined for lameness before medial patellar desmotomy and at months 1, 2, and 3. The femoropatellar joints were examined radiographically and arthroscopically at month 3. All horses were lame on the treated limb at months 1, 2, or 3. Radiographic changes, including fragment formation at the distal aspect of the patella and bone production at the attachment of the middle patellar ligament on the patella, were present in 11 horses at month 3. Articular cartilage fibrillation or detachment was seen arthroscopically on the patellas of all treated limbs. In six horses, loosely attached fragments of bone and cartilage were removed arthroscopically from the distal aspect of the patella of the treated limb. The control limbs were clinically, radiographically, and arthroscopically normal throughout the study. Medial patellar desmotomy results in pathologic changes in the articular cartilage of the patella and adjacent soft tissues. Use of this surgical procedure should be reserved for persistent and confirmed cases of upward fixation of the patella.
Suspected Malignant Hyperthermia after Halothane Anesthesia in a Cat
Authors: BELLAH JAMIE R. , ROBERTSON SHEILAH A. , BUERGELT CLAUS D. , McGAVIN A. DONALD
Published: February 2008

A 6 month old domestic shorthaired cat died of suspected malignant hyperthermia. Anesthesia was induced and maintained with halothane vaporized in oxygen and nitrous oxide, after acepromazine premedication. Before an incision was made, the cat's heart rate dropped from 140 to 90 beats/min concomitant with a drop in blood pressure. Glycopyrrolate administration resulted in severe ventricular tachycardia (340 beats/min). Halothane and nitrous oxide were discontinued and the surgery was abandoned. Lidocaine administration resulted in a normal sinus rhythm. In recovery, the cat was tachypneic and struggling, with a rectal temperature of 40.1°C that quickly increased to 41.4°C. While the cat was being cooled, cardiac dysrhythmias progressed to ventricular fibrillation that was not responsive to cardiorespiratory resuscitation. Blood specimens obtained while the cat was being cooled showed hyperkalemia (10.0 mEq/L) and increased serum creatine kinase activity (780 IU/L). There was extreme extensor rigidity (rigor mortis) within 5 min of cardiac arrest. Results of microscopic and electron microscopic examination of muscle showed occasional perivascular infiltrates of lymphocytes with infrequent perimysial and epimysial neutrophils and a few sarcomeres with streaming of Z‐bands (suggesting a contracted state). Histochemical evaluation of skeletal muscle showed no significant difference between type I and type II fibers.
Strength Characteristics and Failure Modes of Locking‐Loop and Three‐Loop Pulley Suture Patterns in Equine Tendons
Authors: JANN HENRY W. , STEIN LARRY E. , GOOD JAMES K.
Published: February 2008

Size 3–0 polydioxanone was used as a single strand, single braid (3 strands), or double braid (6 strands) to create six suture material‐pattern combinations for equine tenorrhaphy: single‐strand locking loop, single‐braid locking loop, double‐braid locking loop, single‐strand three‐loop pulley, single‐braid three‐loop pulley, and double‐braid three‐loop pulley. Maximum load to failure for the single‐strand locking loop (46.1 ± 2.9 newtons [N]) was less than for all other sutures (range, 103–155 N). The load required to form a 2 mm gap between tendon ends was greater for the single‐braid three‐loop pulley (66.7 ± 6.9 N) and double‐braid three‐loop pulley (85.4 ± 17.7 N) than any other sutures. The load required to produce a 10 mm gap was least for the single‐strand locking loop (34.3 ± 3.9 N) and greatest for the double‐braid three‐loop pulley (131.5 ± 27.5 N). Gap between tendon ends at maximum load was greater for the single‐braid (18.1 ± 0.9 mm) and double‐braid (19.2 ± 2.2 mm) locking loops than for any other sutures. Suture material broke in 53% of the locking‐loop tests but in only 17% of the three‐loop pulley tests. Tendon matrix disruption accounted for 43% of the locking‐loop failures and 77% of the three‐loop pulley failures. The three‐loop pulley pattern provided more support, less tendon distraction, and less tendon matrix constriction and distortion than the locking‐loop pattern. However, considering previously reported in vivo loads, these results suggest that none of these sutures can maintain tendon apposition under normal loading conditions in a living horse. Under these test conditions the limiting factor was tendon matrix for the double‐braid locking loop, single‐braid three‐loop pulley, and double‐braid three‐loop pulley. Suture material failure predominated in the single‐strand locking loop, single‐braid locking loop, and single‐strand three‐loop pulley.
Effects of Acute Hyperventilation on Serum Potassium in the Dog
Authors: MUIR WILLIAM W. , WAGNER ANN E. , BUCHANAN CHERYL
Published: February 2008

The effects of increasing respiratory rates on arterial pH, PaCO2, HCO3, and potassium (K) were measured in normal anesthetized dogs. Hyperventilation resulted in increased pH, decreased PaCO2, decreased HCO3, and decreased K compared with those parameters in spontaneously breathing dogs. The changes were related quantitatively: each 10 mmHg decrease in PaCO2 was associated with a pH increase of 0.1, a HCO3 decrease of 2.0 mEq/L, and a K decrease of 0.4 mEq/L. There were no cardiac arrhythmias or clinical signs of hypokalemia. After termination of hyperventilation, serum K was slower to return to control values than PaCO2. The ratio of the duration of hyperventilation to the time required for return of serum K to control was 0.67.
Surgical Repair of Tibial Tuberosity Avulsion Fractures in Four Horses
Authors: SMITH BARBARA L. , AUER JOERG A. , WATKINS JEFFREY P.
Published: February 2008

Four horses, 2 to 17 years old, were treated for unilateral avulsion fractures of the tibial tuberosity. Two horses were treated successfully with tension band wiring or plating in combination with lag screw fixation. One horse was euthanatized because of implant failure during recovery and one was euthanatized on day 11 because a longitudinal fracture of the tibial tuberosity occurred through the plane of the screws used for stabilization.
A Large Frontonasal Bone Flap for Sinus Surgery in the Horse
Authors: FREEMAN DAVID E. , ORSINI PAUL G. , ROSS MICHAEL W. , MADISON JOHN B.
Published: February 2008

A large frontonasal bone flap was created to treat diseases of the paranasal sinuses in 14 horses. The bone flap was made as wide as possible within the confines of the nasolacrimal duct so the floor of the frontal sinus and the dorsal and ventral conchae could be opened. These openings exposed the nasal passages, maxillary sinuses, and ventral conchal sinus thereby facilitating removal of diffuse and localized lesions from these sites. Diseases treated were ethmoid hematomas (4 horses), sinus cysts (5 horses), cryptococcal granuloma, osteoma, hemangiosarcoma, pus in the ventral conchal sinus, and periapical infection of a second molar. Four horses were euthanatized during or after surgery, one because of postsurgical pleuritis and pneumonia (horse with osteoma) and three because of their primary problems (cryptococcal granuloma, hemangiosarcoma, pus in the ventral conchal sinus). Skin suture abscesses that responded to treatment developed in four horses. Ten horses returned to their intended uses, the sinus flaps healed without blemish, and the original problems did not recur. The frontonasal flap technique provided greater access to all paranasal sinuses than methods described previously.
Upper Airway Function during Maximal Exercise in Horses with Obstructive Upper Airway Lesions Effect of Surgical Treatment
Authors: WILLIAMS J. WESLEY , MEAGHER DENNIS M. , PASCOE JOHN R. , HORNOF WILLIAM J.
Published: February 2008

Upper airway pressure was measured during maximal exercise in 10 Thoroughbred racehorses with naturally occurring upper airway obstruction. Left laryngeal hemiplegia and arytenoid chondropathy resulted in substantial increases (30–40 cm H2O) in inspiratory upper airway pressure (P1), whereas complicated aryepiglottic entrapment and subepiglottic cysts produced only modest increases (15 cm H2O) in P. Uncomplicated aryepiglottic entrapment and grade IV pharyngeal lymphoid hyperplasia produced only slight increases (3–5 cm H2O). In general, surgical procedures restored airway pressures to within normal limits. Subtotal arytenoidectomy improved but did not normalize airway pressures in horses with arytenoid chondropathy. Pharyngeal lymphoid hyperplasia appeared to have little effect on upper airway function.
An Open Patch‐Graft Technique for Correction of Pulmonic Stenosis in the Dog
Authors: ORTON E. CHRISTOPHER , BRUECKER KENNETH A. , McCRACKEN THOMAS O.
Published: February 2008

An open patch‐graft technique for correction of pulmonic stenosis was performed in four dogs. A synthetic patch‐graft was presutured to a partial‐thickness incision in the right ventricular outflow tract and to the pulmonary artery along its cranial border. The pulmonary artery and right ventricle were incised during venous inflow occlusion, and dysplastic pulmonic valve leaflets were excised. The arteriotomy was closed by suturing the caudal margin of the incision to the patch‐graft. The entire procedure was performed during mild hypothermia (30°‐32° C). The mean circulatory arrest time was 5.5 ± 0.2 minutes. The mean systolic pressure gradient across the pulmonic valve before surgery was 121 ±29 mm Hg; after surgery it was 9 ± 2 mm Hg.
Static Strength Evaluation of Sacroiliac Fracture‐Separation Repairs
Authors: RADASCH ROBERT M. , MERKLEY DAVID F. , HOEFLE WILLIAM D. , PETERSON JACK
Published: February 2008

The relative static strengths of seven fixation configurations for the repair of sacroiliac fracture‐separations were determined. The fixation techniques were two 3.5 mm screws, one 4.5 mm screw, one 4.5 mm screw and a pin, two 4.5 mm screws, one 6.5 mm screw, one 6.5 mm screw and a pin, and two 6.5 mm screws. Each configuration was subjected to a torsional, a bending, and a shear disruptive force while the maximum load tolerated before failure was measured. Two screws were stronger than a single screw of similar size, two small screws were stronger than a single larger screw, and a reduction pin added no significant strength to a single screw repair. It was concluded that use of the largest screws possible will maximize the strength of a sacroiliac fracture‐separation repair.
Captopril Provides Sustained Hemodynamic Benefits in Dogs with Experimentally Induced Mitral Regurgitation
Authors: BLACKFORD LEEANN W. , GOLDEN A. LYNELLE , BRIGHT JANICE M. , BRIGHT RONALD M. , GOMPF REBECCA E.
Published: February 2008

Mitral regurgitation was created surgically in 10 dogs. After measurement of baseline hemodynamic parameters on day 2, treatment with captopril (2 mg/kg orally 3 times daily) was begun in five dogs. Five control dogs received no therapy during the study. The hemodynamic parameters were measured again at weeks 6 and 22. In the treated dogs, the forward ejection fraction (FEF) increased slightly and the total peripheral resistance index (TPRI) decreased. In the controls, the FEF decreased and the TPRI increased. Changes in FEF and TPRI were significantly different between the two groups. The change in FEF correlated significantly with the change in TPRI in both groups. Although the most dramatic changes were observed at week 6, the differences persisted throughout the study. Captopril administration resulted in sustained hemodynamic improvement and may, therefore, delay the onset of congestive heart failure in dogs with mitral regurgitation.
Vascular Response of the Equine Radius to Cerclage Devices
Authors: NYROP K. A. , DEBOWES R. M. , FERGUSON H. R. , LEIPOLD H. W. , WILSON J. W. , GUFFY M. M.
Published: February 2008

The arterial blood supply to the diaphysis of the radius, and the vascular reaction when three cerclage devices (cerclage wire, Parham‐Martin band, and a partially contacting band) were applied 2 cm apart, were studied in six adult ponies. The opposite radial diaphysis served as the control. Ponies were euthanatized at weeks 4 and 8. A centrifugal blood flow pattern was demonstrated by microangiography. Larger numbers of medullary arteries exist in equine than in canine and human long bones. Changes in centrifugal blood supply were not identified beneath any of the cerclage devices.
Mandibular Fractures in the Dog A Retrospective Study of 157 Cases
Authors: UMPHLET RANDALL C. , JOHNSON ANN L.
Published: February 2008

One hundred fifty‐seven mandibular fractures in 105 dogs occurred most frequently in male dogs less than 1 year of age. Automobile trauma was the most common cause. Fractures in the premolar region were significantly more frequent than fractures in other regions, and 113 fractures (72%) were open. One hundred forty‐two fractures were stabilized, with tape muzzles being the most common method. Postoperative complications, the most common being dental malocclusion, occurred in 53 fractures (34%). Acceptable cosmetic and functional results were achieved in 89 dogs (85%). Fractures in the rostra1 portion of the mandible had shorter average time to clinical union than other mandibular fractures. Average time to clinical union for fractures in the caudal portions of the mandible was longer than that currently reported.
Intraoperative Monitoring of Ischiatic Nerve Function with Sensory Evoked Potentials
Authors: THOMPSON SUZANNE E. , MOORE MICHAEL P. , LINCOLN JAMES D. , PERSON MYRON W. , BARBEE DAVID D. , BARNES CHARLES D.
Published: February 2008

Serial recordings of sensory evoked potentials (SEP) generated in response to stimulation of each tibial nerve were obtained from 23 anesthetized dogs. Five dogs were anesthetized for 3 hours to evaluate changes in serial SEP during general anesthesia. Nonsurgical and surgical manipulations were performed on one hind limb of five dogs to determine the effects of limb positioning and nerve retraction on SEP. In 13 dogs, the ischiatic nerve was exposed surgically and retracted until the SEP deteriorated and disappeared, to determine the relationship between amount of tension on the nerve and the time to complete deterioration of the SEP. Sensory evoked potential waveforms, which consisted of two to five peaks, were stable throughout the anesthetic period. The first two peaks were the most stable. Latency of the first two peaks was the easiest and most reliable parameter to evaluate. Although the peak latency in recordings from the superior hind limb was always slightly longer, SEP recordings from the inferior limb were good controls to monitor nerve function. There was considerable variation in sensitivity to nerve retraction. The technique proved to be a reliable way to monitor nerve function in normal anesthetized dogs.
Minimal Anesthetic Concentration and Cardiopulmonary Dose Response of Isoflurane in Ducks
Authors: LUDDERS J. W. , MITCHELL G. S. , RODE J.
Published: February 2008

The minimal anesthetic concentration (MAC) for isoflurane was determined during spontaneous ventilation in nine male Peking ducks (7 to 12 weeks of age; 3.0 ± 0.4 kg). While each bird was awake, arterial blood was collected for analysis of pH, PaCO2, and PaO2. After anesthesia was induced with isoflurane in oxygen, MAC was determined for isoflurane in each bird during spontaneous ventilation in a manner similar to MAC determinations in mammals. Pulmonary dose‐response data were collected at 1 MAC and 1.5 MAC. Anesthetic index (Al; an index of anesthetic‐induced apnea) was calculated from ducks that became apneic. The MAC for isoflurane was 1.30 ± 0.23% (mean ± SD). There was a dose‐dependent decrease in ventilation as evidenced by a statistically significant increase in PaCO2. Apnea or unacceptable hy‐percarbia (PaCO2 > 110 mm Hg), or both, were common occurrences at end‐tidal isoflurane concentrations greater than 1.5 MAC. Anesthetic index calculated from four ducks was 1.65 ± 0.13 (mean ± SEM). There was no significant difference between the means of either heart rate or mean arterial blood pressure in birds at 1.0 and 1.5 MAC.
Partial Carpal Arthrodesis for Third Degree Carpal Sprains: A Review of 45 Carpi
Authors: WILLER R. L. , JOHNSON K. A. , TURNER T. M. , PIERMATTEI D. L.
Published: February 2008

The efficacy of partial carpal arthrodesis was evaluated retrospectively in 39 dogs (45 carpi) with severe sprains of the middle carpal joints, the carpometacarpal joints, or both. The carpo‐metacarpal joint was the most frequently injured joint. Jumping or falling from heights was the cause of injury in 49% of these animals. Of the 25 owners who responded to a mailed questionnaire (mean follow‐up, 32 months), all stated their animal had improved or greatly improved after partial carpal arthrodesis and all were pleased or very pleased with the final surgical result. Hyperextension persisted in 11 % of the cases and degenerative joint disease of the antebrachiocarpal joint was present in 15.5% of the cases. No dogs with partial carpal arthrodesis required panarthrodesis at a later date.
Subtotal Canine Prostatectomy with the Neodymium: Yttrium‐Aluminum‐Garnet Laser
Authors: HARDIE E. M. , STONE E. A. , SPAULDING K. A. , CULLEN J. M.
Published: February 2008

A technique was developed for subtotal prostatectomy in dogs with the neodymium:yttrium‐aluminum‐garnet (Nd:YAG) laser. In six normal dogs, full‐thickness necrosis of the prostate occurred if the central‐lateral region within 5 mm of the urethra was photoablated at 60 watts for 1 second. Moderate to superficial necrosis occurred when the prostate within 5 mm of the urethra was photoablated at 35 watts for 2 seconds or 60 watts for 0.5 second. At necropsy, leakage of the urethra occurred in two dogs at sites treated at 60 watts for 1 second. In a clinical study, complications associated with subtotal prostatectomy with the Nd:YAG laser (n‐6) were compared with complications associated with prostatic drainage (n = 6) in dogs with prostatic disease. Intraoperative death (2/6 dogs) and nocturnal incontinence (4/4 surviving dogs) occurred with subtotal prostatectomy. Uncontrolled prostatic infection (2/6 dogs) occurred with prostatic drainage and resulted in the death of one dog on day 11. Four of five dogs surviving prostatic drainage developed recurrent urinary tract infection.
Transendoscopic Nd:YAG Laser Surgery for Treatment of Epiglottal Entrapment and Dorsal Displacement of the Soft Palate in the Horse
Authors: TATE LLOYD P. , SWEENEY CRAIG L. , BOWMAN KARL F. , NEWMAN HY C. , DUCKETT WENDY M.
Published: February 2008

Transendoscopic neodymium:yttrium‐aluminum‐garnet (Nd:YAG) laser was used to treat 12 standing horses with epiglottic entrapment (EE) or dorsal displacement of the soft palate (DDSP), or both. In four horses, transendoscopic laser staphylectomy was performed. The most common presenting complaints were respiratory stridor, cough, and exercise intolerance. Ten horses with EE healed without epiglottic complications; in one horse, partial adhesion of the aryepiglottic fold to one side of the epiglottis was corrected surgically through a laryngotomy incision. One horse with DDSP had no further signs, one continued to have continual DDSP, and two had induced DDSP. Transendoscopic Nd:YAG laser proved to be a feasible means of correcting EE and selected cases of DDSP.
Intra‐Articular Replacement of Bovine Cranial Cruciate Ligaments with an Autogenous Fascial Graft
Authors: CRAWFORD WILLIAM H.
Published: February 2008

Transected cranial cruciate ligaments in nine Holstein heifers were replaced with an autograft harvested from fascia on the medial surface of the gluteobiceps muscle and a connected segment of the lateral patellar ligament. There was minimal lameness at month 1, and all animals were sound by month 2. There was no evidence of degenerative joint disease in any stifles examined at necropsy on days 90, 120, or 365. Augmented healing of the severed cranial cruciate ligaments occurred in several animals. The mean failure strength of the cranial cruciate ligament replacements was 29.7% of the failure strength of the contralateral normal cranial cruciate ligament in four heifers. The technique was successful in eight of 13 bulls and cows with ruptured cranial cruciate ligaments. Animals treated successfully had significantly lower body weights than those with unsuccessful outcomes.
Status Epilepticus after Ligation of Portosystemic Shunts
Authors: HARDIE E. M. , KORNEGAY J. N. , CULLEN J. M.
Published: February 2008

Status epilepticus developed in four dogs, 2 to 3 days after ligation of an extrahepatic portosystemic shunt. Pentobarbital or phenobarbital intravenously was required to control seizure activity. Two dogs treated with phenobarbital recovered. Exacerbation of hepatic encephalopathy secondary to metabolic changes after surgery may be a cause of this syndrome. A treatment protocol for status epilepticus after ligation of a portosystemic shunt is proposed.
A Comparison of Xylazine–Diazepam–Ketamine and Xylazine–Guaifenesin–Ketamine in Equine Anesthesia
Authors: BROCK N. , HILDEBRAND S. V.
Published: February 2008

After sedation with xylazine (0.3 mg/kg intravenously [IV]), anesthesia was induced in six healthy horses with ketamine (2.0 mg/kg IV) and guaifenesin (100 mg/kg IV), diazepam (0.05 mg/kg IV), or diazepam (0.10 mg/kg IV). Anesthesia was maintained with halothane for 30 minutes. Heart rate, respiratory rate, direct arterial blood pressure, arterial blood gas, and pH measurements were made before, and at set intervals after, induction of anesthesia. Quality and characteristics of induction and recovery were evaluated objectively by an independent observer unaware of the protocol used. There were no significant differences among the three protocols from pre‐induction values for arterial blood pressure, blood gas values, and pH. There was significantly greater ataxia at induction with the use of guaifenesin. The nature of induction, transition to and recovery from general anesthesia were comparable between guaifenesin and the higher dose of diazepam. Because of movements and difficulty with intubation, the lower dose of diazepam was considered unsatisfactory. It was concluded that diazepam (0.10 mg/kg) could be substituted for guaifenesin (100 mg/kg) to produce comparable quality of anesthesia in horses.
Closed Suction Drainage in the Treatment of Infectious Arthritis of the Equine Tarsocrural Joint
Authors: ROSS MICHAEL W. , ORSINI JAMES A. , RICHARDSON DEAN W. , MARTIN BENSON B.
Published: February 2008

Infectious arthritis of the tarsocrural joint was treated in 13 horses with closed suction drainage through a flat, fenestrated, latex (Jackson‐Pratt) drain, broad‐spectrum antimicrobial agents, nonsteroidal anti‐inflammatory drugs, and bandage immobilization. In 11 horses, arthroscopic lavage and debridement were also performed. Ingress drains were placed for lavage in six horses. Ten horses returned to their previous level of competition or were sound. One horse raced but had lameness of the affected tarsocrural joint and dropped in racing class; one horse was euthanatized because of laminitis in the supporting limb; and one horse was lame, but useful as a breeding animal. Closed suction drainage appeared to be a useful treatment in horses with infectious arthritis. Although arthroscopy was not necessary, it facilitated fibrin removal, lavage, and partial synovectomy. Because of the development of Pseudomonas superinfection in one horse, the use of simultaneous ingress catheters was not recommended.
The Effects of Surgical Isolation and Application of Polypropylene Spiral Prostheses on Tracheal Blood Flow
Authors: KIRBY BARBARA M. , BJORLING DALE E. , RANKIN JOHN H. G. , PHERNETTON TERRANCE M.
Published: February 2008

Tracheal blood flow before and after division of the segmental tracheal blood supply with and without application of a polypropylene spiral prosthesis was measured in dogs by radiolabeled microsphere injection. Ischemia of the central part of the trachea, from the mid‐cervical to mid‐thoracic regions, was observed immediately after division of the segmental tracheal blood supply with and without polypropylene spiral prosthesis application. On day 3, tracheal blood flow was significantly decreased in the central part of the trachea with and without polypropylene spiral prosthesis application. On day 7, tracheal blood flow was significantly increased throughout the trachea, with no significant differences between animals with and without prosthesis application. There was no evidence of a collateral source of blood supply to the trachea. Surgical division of the segmental tracheal blood supply of the entire trachea is not recommended.
Excision of Neoplasms of the Bovine Lower Eyelid by H‐Blepharoplasty
Authors: WELKER B. , MODRANSKY P. D. , HOFFSIS G. F. , WYMAN M. W. , RINGS D. M. , HULL B. L.
Published: February 2008

Neoplasms of the lower eyelid in 14 cattle were treated by wide surgical excision and H‐blepharoplasty. Healing was by first intention, and cosmetic results were satisfactory in all cases. Lid function was satisfactory in 12 cattle, and there was no evidence of recurrence after at least 6 months in 12 cattle. This therapy can be recommended for large infiltrative masses on the lower lid if there is no evidence of bony involvement, metastasis, or involvement of both puncta at the medial canthus.
Induction of Anesthesia with Diazepam‐Ketamine and Midazolam‐Ketamine in Greyhounds
Authors: HELLYER PETER W. , FREEMAN LISA C. , HUBBELL JOHN A. E.
Published: February 2008

Anesthesia was induced in 14 greyhounds with a mixture of diazepam or midazolam (0.28 mg/kg) and ketamine (5.5 mg/kg), and maintained with halothane. There were no significant differences in weight, age, or duration of anesthesia between the treatment groups. Time to intubation with diazepam‐ketamine (4.07 ± 1.43 min) was significantly longer than with mid‐azolam‐ketamine (2.73 ± 0.84 min). Heart rate, respiratory rate, Paco2, and arterial pH did not vary significantly during anesthesia in either treatment group. Arterial blood pressures, Pao2, halothane vaporizer setting, and body temperature changed significantly from baseline values in both treatment groups during anesthesia. Times to sternal recumbency and times to standing were not significantly different. These data suggest that both diazepam‐ketamine and mid‐azolam‐ketamine are useful anesthetic combinations in greyhounds. In combination with ketamine, midazolam offers little advantage over diazepam.