bluuebunny/crossref_metadata_2025 huggingface dataset:
Partial Arytenoidectomy in the Horse Using an Extralaryngeal Approach
Authors: HAY WILLIAM P. , TULLENERS ERIC P. , DUCHARME NORM G.
Published: February 2008

An extralaryngeal approach to partial arytenoidectomy in the horse was developed by in vitro experiments on isolated larynges and then on intact equine cadavers. The goals of the approach were to preserve the laryngeal mucosa, eliminate the need for a laryngotomy or tracheotomy, and minimize postoperative complications. The new approach was evaluated in seven horses with normal upper respiratory tracts. Left laryngeal hemiplegia was surgically created, and, after a 30‐day convalescence, left partial arytenoidectomy was performed using an extralaryngeal approach. The left‐to‐right hemilaryngeal ratio was calculated before and after left recurrent laryngeal neurectomy and 60 days after partial arytenoidectomy. Left partial arytenoidectomy was successfully completed in all horses without performing a laryngotomy or tracheotomy. Preservation of the laryngeal mucosa (6/7 horses) and apparent stabilization of the adjacent soft tissue (6/7 horses) was achieved. In one horse, a 1 ‐cm laryngeal mucosal tear healed without complication, and in another some collapse of adjacent soft tissue occurred when a retention suture failed. The mean left‐to‐right hemilaryngeal ratio was significantly increased compared to horses with left laryngeal hemiplegia, but it remained significantly less than the pre‐recurrent laryngeal neurectomy ratio (p < .05). Coughing, aspiration, and airway narrowing were not observed. Partial arytenoidectomy could be reliably performed through an extralaryngeal approach in horses with a normal underlying arytenoid cartilage with preservation of the laryngeal mucosa.
Marsupialization of Umbilical Vein Abscesses With Involvement of the Liver in 13 Calves
Authors: STEINER ADRIAN , LISCHER CHRISTOPH J. , OERTLE CAROLINE
Published: February 2008

Omphalophlebitis with liver involvement was diagnosed by ultrasonography in 13 calves. In the initial surgical procedure, the infected umbilical vein was marsupialized by cranial trans‐location in a median celiotomy and was flushed daily until healing occurred. In a second surgical procedure, the contracted umbilical vein was removed. Nine calves were clinically healthy after treatment. One had reformation of two abscesses because of inadequate post‐surgical treatment. One calf was euthanatized because of an intussusception of the small intestine, and two calves had adverse reactions and developed septic shock when some of the lavage fluid, which was applied under pressure, entered the systemic circulation. It was concluded that umbilical vein abscesses should not be flushed under pressure in calves younger than 2 months of age. The principal advantages of cranial translocation of the umbilical vein in a median celiotomy are that only one abdominal incision is required and that the infected umbilical vein tissue does not have to be passed intraabdominally to a paramedian position.
Ex Vivo Biomechanics of Kirschner‐Ehmer External Skeletal Fixation Applied to Canine Tibiae
Authors: BOUVY BERNARD M. , MARKEL MARK D. , CHELIKANI SUDHAKAR , EGGER ERICK L. , PIERMATTEI DONALD L. , VANDERBY RAY
Published: February 2008

The purpose of this study was to determine the respective contribution of each of the following parameters to the compressive, bending, and torsional rigidity of the Kirschner‐Ehmer (KE) external fixation splint as applied to canine tibiae with an osteotomy gap: bilateral versus unilateral splints; increasing the number of fixation pins; altering the diameter of fixation pins and side bars; decreasing side bar distances from the bone; increasing pin separation distances in each pin group; decreasing distances between pin groups; altering pin clamp orientation; and altering side bar conformation. Bilateral splints were 100% (mean) stiffer than unilateral splints, with stiffness enhanced to the greatest extent in mediolateral bending and torsion. Increasing pin numbers stiffened both bilateral (mean, 41%; 8 versus 4) and unilateral splints (mean, 14%; 8 versus 4). Medium KE splints were 85% (mean) stiffer than small KE splints. Decreasing side bar distances to the bone from 1.5 cm to 1.0 cm to 0.5 cm increased stiffness of both bilateral and unilateral splints by a mean of 13% to 35%. Widening pin spacing from 1.67 cm to 2.5 cm increased stiffness in craniocaudal bending only (56% increase, bilateral splints; 73% increase, unilateral splints). Decreasing the distance between pin groups from 5.84 cm to 2.5 cm increased stiffness in torsion between 23% (unilateral splints) and 45% (bilateral splints) and decreased stiffness of unilateral splints by 29% in craniocaudal bending. Altering pin clamp configuration so that the bolts of the clamp were inside the side bar rather than outside the side bar increased stiffness in axial compression only (73% increase, bilateral splints; 54% increase, unilateral splints). Conforming the lateral side bar to the tibiae increased only axial compressive stiffness by 77% but was no different than placing the clamps inside the side bars of an unconformed bilateral splint. These results quantify the relative importance of specific parameters affecting KE splint rigidity as applied to unstable fractures in the dog.
Endotracheal Tube Displacement During Cervical Manipulation in the Dog
Authors: QUANDT JANE E. , ROBINSON ELAINE P. , WALTER PATRICIA A. , RAFFE MARC R.
Published: February 2008

A retrospective study was performed to identify positional changes of endotracheat tubes (ETT) during cervical spine radiography in 153 dogs. Three neck positions were identified: traction, hyperextension, and flexion. A properly placed ETT was defined as having the caudal tip of the tube located between the caudal half of the fourth cervical (C) vertebra (C4) and the caudal half of C7. In the traction position, before neck flexion and extension, the caudal tip of 13% of ETT were located caudal to C7, and one tube was in the endobronchial position at the seventh thoracic (T) vertebra (T7). In the hyperextended position, 60% of ETT moved cranially. The average distance moved was 0.6 vertebral spaces. In the flexed position, all ETT moved caudally. The average distance moved was 3.5 vertebral spaces, with 81.8% of ETT located caudal to C7 and seven tubes in endobronchial positions. Endotracheal tube occlusion caused by kinking at the atlanto‐occipital joint was seen in four dogs during flexion of the neck. Based on this study, ETT position should be monitored during cervical manipulation.
Clinical and Pathologic Effects of a Modified Technique for Application of Spiral Prostheses to the Cervical Trachea of Dogs
Authors: COYNE BONNIE E. , FINGLAND ROGER B. , KENNEDY GEORGE A. , DEBOWES RICHARD M.
Published: February 2008

A modified surgical technique for application of extraluminal polypropylene spiral prostheses (PSP) to the trachea was developed. A portion of the segmental blood supply to the collapsed segment of trachea was maintained by fenestrating rather than completely dissecting the right lateral pedicle. Polypropylene spiral prostheses were applied to the cervical trachea of 12 dogs (group I) via the modified technique and to 12 dogs (group II) with the identical surgical dissection but without PSP applied. Clinical abnormalities included mild coughing in group I dogs and swelling of the incisions in both groups. Limited necrosis and moderate degeneration and inflammation were observed histologically in both groups. Pathologic changes were worse in the caudal cervical segment of the trachea. Mucosal regeneration was present on day 10 in both groups. Transmural tracheal necrosis was not observed. The modified technique for application of PSP is recommended by the authors because it provides adequate surgical exposure and the blood supply preserved by segmentally dissecting the right lateral pedicle is adequate to maintain tracheal viability.
Effects of Thiopental, Ketamine, Diazepam, Xylazine, and Nitrous Oxide on EEG Spike Activity and Convulsive Behavior During Enflurane Anesthesia in Atropinized Cats Effect of Increasing Inhalant Concentrations
Authors: HIKASA YOSHIAKI , KUBOTA MASAAKI , TAKASE KATSUAKI , KAKUTA TOMOKO , OGASAWARA SHIGEO
Published: February 2008

The effects of thiopental, ketamine, diazepam, xylazine, and nitrous oxide, and the combinations of thiopental‐nitrous oxide and ketamine‐nitrous oxide, on both enflurane‐induced electroencephalographic (EEG) spike activity and convulsive behavior were measured quantitatively in atropinized cats receiving enflurane with controlled ventilation. Pretreatments with thiopental, ketamine, and diazepam reduced both EEG spike frequency and amplitude at 2.5% to 4.5% inspired enflurane but did not abolish spike activity. Nitrous oxide (66% of inspired gas) did not significantly alter spike frequency or amplitude during 2.5% to 4.5% inspired enflurane, but the combination of thiopental‐nitrous oxide or ketamine‐nitrous oxide reduced EEG spike activity during 2.5% inspired enflurane. Enflurane‐induced convulsive score was markedly suppressed by thiopental and ketamine and was significantly reduced by diazepam, xylazine and nitrous oxide. The combinations of thiopental‐nitrous oxide and ketamine‐nitrous oxide greatly reduced behavioral‐convulsive responses induced by 2.5% to 4.5% inspired enflurane.
Effects of Perioperative Granulocyte Colony‐Stimulating Factor on Horses With Ascending Colonic Ischemia
Authors: SULLIVAN KENT E. , SNYDER JACK R. , MADIGAN JOHN E. , PASCOE JOHN R. , FARVER THOMAS B. , THURMOND MARK C. , ANDRESEN JEFF W.
Published: February 2008

Granulocyte colony‐stimulating factor (G‐CSF) is a glycoprotein that regulates the proliferation and maturation of hematopoietic progenitor cells and modulates the function of mature neu‐trophils. The responses to administration of G‐CSF alone, and in combination with antimicrobials, were studied in an equine model of ascending colon ischemia. Complete segmental colonic ischemia (3.75 hours) with pelvic flexure enterotomy was created in four treatment groups. Group 1 horses received recombinant canine G‐CSF (10 μg/kg, every 24 hours, intramuscularly), gentamicin sulfate (2.2 mg/kg, every 8 hours, intravenously), and potassium penicillin G (40,000 lU/kg, every 6 hours, intravenously). Group 2 horses were treated with the G‐CSF vehicle and antimicrobials as for group 1. Group 3 horses received G‐CSF and the antimicrobial drug vehicles, and group 4 horses served as the untreated control receiving G‐CSF vehicle and antimicrobial vehicles. The results for 20 horses, five horses in each group, were compared. Treatment with G‐CSF was associated with an increased concentration of white blood cells, band neutrophils, neutrophils, lymphocytes, and monocytes in the peripheral blood after surgery. Antimicrobial administration had no detectable effect on cell concentrations after surgery. Administration of G‐CSF was associated with an increased concentration of nucleated cells in the peritoneal fluid including neutrophils, small mononuclear cells and large mononuclear cells. Horses that developed incisional infections had lower neutrophil concentrations in the peripheral blood on postoperative day 2 than horses without infected incisions. These results suggested that the prophylactic administration of G‐CSF may be useful in the treatment of patients at risk for developing neutropenia after surgery.
Transsplenic Portal Catheterization Surgical Technique and Use in Two Dogs With Portosystemic Shunts
Authors: SCHULZ KURT S. , MARTIN ROBERT A. , HENDERSON RALPH A.
Published: February 2008

The portal vasculature can be accessed by using a through‐the‐needle catheter system to pass a catheter through the splenic parenchyma and into a major splenic vein at the hilus. The authors have termed this technique transsplenic portal catheterization (TPC). Transsplenic portal catheterization is indicated for portal angiography, portal pressure measurement, and chronic portal blood sampling. Clinical applications of this technique include use in diagnosis and surgical management of portosystemic shunts and differentiation of prehepatic, hepatic, and posthepatic hypertension. This report describes the technique of transsplenic portal catheterization. Clinical use of this technique in two cases of portosystemic shunts are included.
Resection of Subvalvular Aortic Stenosis Surgical and Perioperative Management in Seven Dogs
Authors: KOMTEBEDDE JAN , ILKIW JAN E. , FOLLETTE DAVID M. , BREZNOCK EUGENE M. , TOBIAS ANTHONY H.
Published: February 2008

Open heart surgery was performed during cardiopulmonary bypass (CPB) to surgically correct subvalvular aortic stenosis in seven dogs. After initiation of total CPB, cardiac arrest was induced by antegrade and retrograde administration of blood cardioplegia. The subvalvular fibrous stenosis was resected through a transverse aortotomy. Intraoperatively and postop‐eratively, dobutamine, nitroprusside, lidocaine, blood(‐products), and crystalloid solutions were used to manage hypotension and optimize cardiac index.

Aortic cross‐clamp time varied from 73 to 166 minutes, and duration of CPB varied from 130 to 210 minutes, latrogenic incision into the mitral valve in two dogs was the most significant introperative complication. Postoperative complications included: hypoproteinemia (n = 7), premature ventricular depolarization (n = 6), increased systemic vascular resistance index (n = 5), increased O2 extraction (n = 3), pulmonary edema (n = 2), and decreased cardiac index (n = 1). All seven dogs were discharged alive and in stable condition. Six dogs are alive and in stable condition after a mean follow up of 15.8 months.

This is the first detailed report of CPB in a series of clinical veterinary patients. Using the techniques described in this paper, open heart surgery of considerable duration can be performed successfully in dogs with significant myocardial hypertrophy and endomyocardial fibrosis secondary to subvalvular aortic stenosis.
Evaluation of Thoracic Duct Healing After Experimental Laceration and Transection
Authors: HODGES CARLOS C. , FOSSUM THERESA W. , EVERING WINSTON
Published: February 2008

Healing of the thoracic duct (TD) was evaluated clinically and histologically in six healthy dogs. A 2.5 cm longitudinal laceration of the caudal TD was created in three dogs and the caudal TD was completely transected in three other dogs. The site of the defect was identified by placing one 4‐0 stainless steel suture in the tissue adjacent to the TD defect. All dogs developed a chylous effusion confirmed by biochemical analysis. By five days after surgery in dogs with TD lacerations, and by 10 days after surgery in dogs with TD transections, thoracic effusion had ceased. Lymphangiography, performed seven days after resolution of thoracic effusion, showed TD patency only in the dogs with TD lacerations. The TD did not appear to be patent in dogs with TD transections. Histologically, in dogs with TD lacerations, one moderately dilated lymphatic vessel was seen at the surgical site in one animal and the thoracic duct and other lymphatics in the two other dogs appeared normal. Minimal perivascular accumulations of neutrophils, macrophages, and lymphocytes were present adjacent to two lymphatics in one animal. A mild increase in fibrous connective tissue and neovascularization was present in the adjacent subpleura. In dogs with complete transections, three to six dilated lymphatics were present at the transection site. Mild thickening of the tunica media was present in one thoracic duct, associated with a “J”‐shaped area of condensed collagen, presumed to be a collapsed thoracic duct in one animal. Mild to moderate accumulations of macrophages, lymphocytes, and moderate neovascularization was present in the surrounding tissue, separating it from the underlying connective tissue. Healed TDs could not be differentiated histologically from normal TDs.
Subtotal Colectomy With Surgical Stapling Instruments Via a Trans‐cecal Approach for Treatment of Acquired Megacolon in Cats
Authors: KUDISCH MICHELE , PAVLETIC MICHAEL M.
Published: February 2008

Surgical stapling equipment was used to perform an end‐to‐end colonic anastomosis in 15 cats for the treatment of acquired megacolon. An end‐to‐end stapling device was passed to the anastomotic site by a trans‐cecal approach. Subsequent closure of the cecal incision was accomplished with a thoracoabdominal stapling device. Two cats had hemorrhagic episodes immediately after surgery that required blood transfusions. All 15 cats have had good to excellent health after subtotal colectomy and colocolostomy performed using this stapling technique. Results of this study have demonstrated that “single surgical field” placement of the end‐to‐end stapling device has the primary advantage of simplicity and a lower chance of contamination compared with (dual field) rectal passage of similar devices. Closure of the cecal access incision is easily performed without reducing the diameter of the large intestinal lumen. The stapling technique provided an efficient and consistent method for anastomosis of the large bowel in cats.
Endoscopic Examination and Treatment of Paranasal Sinus Disease in 16 Horses
Authors: RUGGLES ALAN J. , ROSS MICHAEL W. , FREEMAN DAVID E.
Published: February 2008

Sixteen horses with suspected paranasal sinus disease had endoscopic examination of the paranasal sinuses with a 4.0 mm arthroscope either while standing and sedated (14 horses) or under general anesthesia (two horses). Endoscopic diagnosis included sinusitis (four horses), sinus cyst (three horses), hemorrhage (three horses), neoplasia (three horses), and tooth root abnormalities (two horses). No abnormalities were detected in one horse. Endoscopic findings concurred with the radiographic findings in 13 horses (81%). Samples of sinus contents for bacteriologic (eight horses) and histologic examinations (five horses) were obtained using sinus endoscopy. Diagnostic sinus endoscopy was combined with debridement, lavage, and suction as a therapeutic technique in 10 horses. In three horses, sinus exploration was performed after diagnostic endoscopy confirmed sinus disease, whereas in three horses, further therapy was not recommended after sinus endoscopy. Clinical signs of sinus disease resolved in 11 horses (69%) overall and in eight of 10 horses (80%) with sinusitis, cyst formation, or hemorrhage using endoscopic techniques alone. Mild, local subcutaneous emphysema occurred at the portal sites in all horses, but healing occurred without additional complications, latrogenic damage to sinus structures occurred in one horse. Sinus endoscopy was useful in the diagnosis and management of paranasal sinus disease and avoided the need for exploratory sinusotomy in some horses.
The Effect of Long‐Term Bone Plate Application for Fixation of Radial Fractures in Dogs
Authors: GLENNON JOSEPH C. , FLANDERS JAMES A. , BECK KATHY A. , TROTTER ERIC J. , ERB HOLLIS N.
Published: February 2008

This study was divided into two phases. In the in vitro phase, a stainless steel bone plate was applied to the cranial surface of the radius in 14 canine limbs. The effect of the presence of a bone plate on bone density analysis using radiographic photodensitometry (RP) was evaluated by comparing the density measurement of the unplated limb to the density measurement of the plated limb. The optical density of the plated bones was 12% greater than that of the unplated bones. This information was used as a correction factor for the in vivo study. In the in vivo phase, 23 dogs with radial and ulnar fractures were examined for complications associated with the long‐term application of a stainless steel plate applied to the cranial surface of the radius. In 14 dogs, RP analysis was used to compare the plated limb with the normal, contralateral limb. No significant differences in radial cortical bone density existed between the plated limb and the contralateral limb after taking into account the effect a bone plate had on photodensitometry readings. There was no significant correlation between the change in radial cortical density and the duration of bone plate application, suggesting that a steady state between bone loss and bone production occurs after long‐term plate fixation of the fractured canine radius. The majority (87%) of the dogs with a plate applied to the radius greater than 1 year had normal limb usage when standing, walking, or running.
Influence of Cholinergic Blockade on the Development of Epinephrine‐Induced Ventricular Arrhythmias in Halothane‐ and Isoflurane‐Anesthetized Dogs
Authors: LEMKE KIP A. , TRANQUILLI WILLIAM J. , THURMON JOHN C. , BENSON G. JOHN , OLSON WILLIAM A.
Published: February 2008

The arrhythmogenic effects of anesthetic drugs are assessed using the arrhythmogenic dose of epinephrine (ADE) model. The purpose of this study was to determine the influence of cholinergic blockade (CB) produced by glycopyrrolate (G) on ADE in 1.5 minimum alveolar concentration (MAC) halothane (H)‐ and isoflurane (I)‐anesthetized dogs. Eight dogs (weighing between 12.5 and 21.5 kg) were randomly assigned to four treatment groups (H, HG, I, and IG) and each treatment was replicated three times. Anesthesia was induced and maintained with H (1.31%, end‐tidal [ET]) or I (1.95%, ET) in oxygen. Ventilation was controlled (carbon dioxide [PCO2] 35 to 40 mmHg, ET). G was administered 10 minutes before ADE determination at a dose of 22 μg/kg (11 μg/kg, intravenous [IV] and 11 μg/kg, intramuscular [IM]). The ADE was determined by IV infusion of epinephrine at sequentially increasing rates of 1.0, 2.5, and 5.0 μg/kg/min; and defined as the total dose of epinephrine producing at least four ectopic ventricular contractions (EVCs) within 15 seconds during a 3‐minute infusion and up to 1 minute after the end of the infusion. Total dose was calculated as the product of infusion rate and time to arrhythmia. Data were analyzed using a randomized complete block analysis of variance. When significant (P < .05) F values were found a least significant difference test was used to compare group means. Values are reported as means ± standard error. The ADE (μg/kg) for H, HG, I, and IG were 1.53 ± 0.08, 3.37 ± 0.46, 1.61 ± 0.21, and > 15.00, respectively. Heart rates (HRs) (beats/min) and systolic pressures (mmHg) at the time of arrhythmia formation for H, HG, I, and IG were (60.3 ±4.0 and 142.0 ± 7.6), (213.0 ± 13.1 and 239.2 ± 7.1), (62.9 ± 4.5 and 151.9 ± 6.3), and (226.3 ± 6.1 and 323.5 ± 3.4), respectively. The H and I ADE were not different. The HG ADE was significantly less than the IG ADE. The H and I ADE were significantly less than the HG and IG ADE. We conclude the following from the results of this study of epinephrine infusion in halothane‐ and isoflurane‐anesthetized dogs: (1) two distinct mechanisms are responsible for the development of arrhythmias, (2) CB produced by G significantly increases ADE but is associated with higher rate pressure products (RPP) and myocardial work, and (3) ADE methodology could be improved by determining ADE with and without CB.
Ventricular Arrhythmias in Dogs Undergoing Splenectomy: A Prospective Study
Authors: MARINO DOMINIC J. , MATTHIESEN DAVID T. , FOX PHILLIP R. , LESSER MICHAEL B. , STAMOULIS MARK E.
Published: February 2008

Fifty dogs undergoing splenectomy for splenic masses (n = 40), torsion of the splenic pedicle (n = 5), and immune‐mediated disease (n = 5) were evaluated preoperatively and postoperatively for ventricular arrhythmias and the relationship between ventricular arrythmia and splenic disease. The ability of 1 ‐minute electrocardiograms recorded every 6 hours (ECGs/q6hr) to detect ventricular arrythmia was compared with continuous 48‐hour Holter monitoring. Based on continuous Holter monitoring, splenectomized dogs had a high incidence (22 of 50) of rapid ventricular tachycardia. The incidence of rapid ventricular tachycardia was significantly higher in dogs with ruptured splenic masses (16 of 23) than without rupture (1 of 17) (P< .001). When the results of ECG/q6hr were compared with the results of continuous Holter monitoring, ECG/q6hr was normal in 29% (4 of 14) of dogs with rapid ventricular tachycardia at > 3,000 ventricular extrasystoles (VE)/hr; 50% (4 of 8) of dogs with rapid ventricular tachycardia at 1,000 to 3,000 VE/hr and 100% (6 of 6) of dogs with 10 to 300 VE/hr without rapid ventricular tachycardia. Although dogs undergoing splenectomy had a high incidence of ventricular arrythmias, one‐minute ECGs/q6h were unreliable for detection of ventricular arrythmias even when high‐frequency extrasystoles occurred.
The Effect of Trans‐Stifle External Skeletal Fixation and Hyaluronic Acid Therapy on Articular Cartilage in the Dog
Authors: KELLER WILLARD G. , ARON DENNIS N. , ROWLAND GEORGE N. , ODEND'HAL STEWART , BROWN JOHN
Published: February 2008

Transarticular external skeletal (TES) fixators were applied unilaterally to the stifle joints of 10 young adult dogs. After 4 weeks, the fixators were removed from all dogs. Two dogs were not allowed a remobilization period, whereas 8 dogs were provided with 4 additional weeks of weight‐bearing activity in a kennel run. Four dogs were given high‐molecular weight hyaluronic acid by intra‐articular injection weekly during the remobilization period. Clinical gait evaluations and range of motion were determined during the remobilization period. Articular cartilage samples from both stifle joints of all dogs were evaluated histologically and histochemically. No significant differences in gait scores or range of motion were noted between treated and untreated dogs. Articular cartilage proteoglycan content was reduced after 4 weeks of trans‐stifle external skeletal fixation as determined by loss of alcian blue (AB) histochemical staining. Improved homogeneity of histochemical staining was observed after remobilization. However, remobilization was associated with histological damage to the surface and tangential layers of articular cartilage. Remobilization combined with hyaluronic acid (HA) therapy improved histochemical staining and reduced structural damage to articular cartilage when compared with remobilization alone.
Use of a Cortico‐Cancellous Bone Graft in the Repair of a Cleft Palate in a Dog
Authors: ISHIKAWA YOSHIMI , GORIS RICHARD C. , NAGAOKA KATSUYOSHI
Published: February 2008

We report the successful use of a cortico‐cancellous bone graft to repair a cleft of the secondary palate in a 6‐month‐old Akita dog. The cleft extended from the incisal papilla to the posterior border of the soft palate. It was 10 mm wide in the hard palate and 16 mm in the soft palate. The cleft was repaired using the “push‐back” method with single‐pedicled mucoperiosteal flaps to close the cleft in the soft tissues, and a free bone graft from the tibia (cortex with cancellous bone attached) to fill the defect in the hard palate. Two and one‐half years after the operation the graft was indistinguishable from surrounding bone on radiographs. Maxillary growth appeared to have progressed normally, resulting in normal occlusion.
Effects of Halothane, Enflurane, and Isoflurane on Supraventricular and Ventricular Rate in Dogs With Complete Atrioventricular Block
Authors: DAY THOMAS K. , MUIR WILLIAM W.
Published: February 2008

Complete atrioventricular (AV) block was produced in 32 chloralose‐anesthetized autonomically intact dogs to determine the effects of halothane, enflurane, and isoflurane on supraventricular and ventricular rate. Halothane (n = 17), enflurane (n = 6), and isoflurane (n = 9) were administered in three separate experiments in sequential minimum alveolar concentration (MAC) multiples of 0.5, 1.0, 1.5, 2.0, 1.5, and 1.0. Supraventricular rate, ventricular rate, and mean arterial blood pressure (MAP) were measured and recorded at baseline and after a 20‐minute equilibration period of each inhalation anesthetic at each MAC multiple. Increasing concentrations of enflurane and isoflurane significantly decreased supraventricular rate (P< .05). Ventricular rate was not significantly changed by sequential MAC multiples of halothane, enflurane, and isoflurane. Increasing concentrations of halothane, enflurane, and isoflurane significantly decreased MAP with enflurane producing the most significant decrease (P< .05). Ventricular arrhythmias occurred in 5 of 17 dogs anesthetized with halothane and 1 of 9 dogs anesthetized with isoflurane. Inhalation anesthesia can significantly decrease supraventricular rate and MAP, does not alter ventricular rate, and can produce ventricular arrhythmias in dogs with complete AV block.
Morphological Effects of Arthroscopic Partial Synovectomy in Horses
Authors: JONES DIANA L. , BARBER SPENCER M. , JACK SHERMAN W. , DOIGE CECIL E.
Published: February 2008

Gross and microscopic effects of arthroscopic partial synovectomy on synovium and articular cartilage of middle carpal joints were studied in 15 horses. A 7‐mm diameter motorized synovial resector was inserted into each middle carpal joint and arthroscopic partial synovectomy and lavage or arthroscopic lavage alone was performed. Study periods were 0 (three horses), 16 (three horses), and 30 days (six horses). No gross evidence of degenerative joint disease was observed at day 16 or 30. At 30 days, resected areas lacked villi and there was deposition of fibrin on the synovial surface with varying amounts of newly formed fibrovascular tissue. Thirty days after arthroscopic synovectomy, normal synovium had not formed in equine middle carpal joints.
Effect of Ligation on Internal Carotid Artery Blood Pressure in Horses
Authors: FREEMAN DAVID E. , WICK WILLIAM J. DONA , KLEIN LIN V.
Published: February 2008

The effect of a single ligature on back pressure in the internal carotid artery was studied in nine horses. In six anesthetized horses, one internal carotid artery was catheterized 2 cm from its origin and blood pressure was recorded continuously. Then the artery was ligated, pressure was recorded again, and the horses were euthanatized. In another three anesthetized horses, indwelling catheters were placed in both internal carotid arteries and a loose ligature was placed proximal to one catheter. After horses recovered from anesthesia, the ligature was tied and blood pressure was recorded in both arteries on that day and 3 days later, then these horses were euthanatized. The anatomy of the cerebral arteries was examined in all nine horses. Blood pressure in the internal carotid arteries did not change after ligation. Subjectively, collateral channels considered most likely to maintain blood pressure in the ligated internal carotid artery were the caudal intercarotid artery and the cerebral arterial circle. We concluded that ligation of the internal carotid artery would not prevent severe hemorrhage from the internal carotid artery in horses with guttural pouch mycosis until the ligated artery thrombosed to the level of the lesion.
Repair of a Mandibular Defect With a Free Vascularized Coccygeal Vertebra Transfer in a Dog
Authors: YEH LIH‐SENG , HOU SHENG‐MOU
Published: February 2008

Bilateral mandibular defects in a male mongrel dog were repaired. On the left side, a free vascularized coccygeal bone graft that included the median caudal artery and caudal vein was used to correct the defect. On the right side, the defect was bridged with a bone plate and screws. For further immobilization, the muzzle was temporarily taped for 3 weeks and a pharyngostomy tube was used for nutritional support. The dog was able to eat dry commercial food satisfactorily within 2 months of surgery despite mild malocclusion. Radiographs taken 2 months and 18 months postoperatively showed bony union with graft hypertrophy in the left mandible, whereas the right mandibular defect showed protracted nonunion. The results indicate that vascularized coccygeal vertebra transfer provides an alternative for the management of canine mandibular defects.
Biomechanical Evaluation of a Toggle Pin Technique for Management of Coxofemoral Luxation
Authors: FLYNN MICHAEL F. , EDMISTON DAVID N. , ROE SIMON C. , RICHARDSON DANIEL C. , DEYOUNG DAVID J. , ABRAMS C. FRANK
Published: February 2008

Toggle pin stabilization is an accepted technique for the management of coxofemoral (CF) luxation in dogs. The purpose of this study was to determine, in vitro, the respective contributions of several aspects of toggle pin repair to the overall stability of fixation. Factors evaluated were the manner and frequency with which toggle pins oriented on insertion, effect of orientation on toggle pin strength, effect of suture type on ligament prosthesis strength and load sustained by the fixation, and comparison of repair using a modified toggle design to that of capsulorrhaphy. When placed in cadavers using standard technique, conventional toggle pins were found to orient significantly more frequently in one of two possible positions. Mechanical testing of fixations performed in experimentally luxated cadaver hips demonstrated a high (12/20) incidence of toggle pin failure using the conventional implant in the most common orientation. When tested alone, toggle pins were weakest mechanically in this orientation. Rotating the implant 180° increased mean load to failure by 249%. There was no significant difference in load sustained by conventional toggle fixations using No. 2 braided polyester versus 50 lb test monofilament nylon as the suture ligament prosthesis. However, the higher stiffness of the polyester suture may be more favorable for use in this application. Fixation using a toggle rod designed to allow evaluation of construct stability when failure of the toggle is eliminated resulted in an increase in maximum load sustained before luxation (47% of the intact control hips). This load was not significantly different than the resistance to luxation afforded by capsulorrhaphy. This study suggests that when implanting conventional toggle pins, consideration should be given to ensuring placement in the strongest orientation.
The Immediate Effect of Colposuspension on Resting and Stressed Urethral Pressure Profiles in Anaesthetized Incontinent Bitches
Authors: GREGORY SUSAN P. , HOLT PETER E.
Published: February 2008

The aim of this study was to document what changes in the resting and stressed urethral pressure profile occur in the incontinent bitch with urethral sphincter mechanism incompetence (SMI) immediately after colposuspension. Resting and stressed subtracted simultaneous urethral pressure profilometry was performed immediately pre‐ and postcolposuspension in 26 bitches diagnosed with SMI. All of the urethral pressure profiles were measured in anaesthetized bitches using a standard technique and two orientations of the catheter transducers (dorsal and left). Readable pre‐ and postoperative urethral pressure profiles were obtained in 20 of the 26 bitches. Subjective and objective evaluation of the profiles showed significant differences in the profiles pre‐ and postcolposuspension. Immediately postoperatively there were significant (P< .05) increases in functional profile length, maximum urethral closure pressure (MUCP), and distance between the bladder neck and the first negative respiratory peak and stressed spike. There was a significant (P< .001) decrease in the percentage of negative spikes extending below the resting intravesical pressure on the subtracted profile. The pressure transmission profiles were significantly (P< .001) altered by surgery. The findings presented support the hypothesis that colposuspension may restore continence by increasing pressure transmission to the proximal urethra and bladder neck. The results also suggest that immediately after surgery functional urethral length and urethral resistance are increased.
Combined Resection of the Nasal Planum and Premaxilla in Three Dogs
Authors: KIRPENSTEIJN JOLLE , WITHROW STEPHEN J. , STRAW RODNEY C.
Published: February 2008

Surgical techniques for removal of tumors that affect the nasal planum or the premaxilla have been described. For extensively invasive malignancies, these techniques may be inadequate if used alone to achieve wide surgical margins. An operative technique that combines resection of the nasal planum and premaxilla has been developed for extensive malignant tumors of the nasal planum or premaxilla. This technique was used in three dogs and resulted in an acceptable cosmetic appearance and good function and tumor control. Complications after surgery included minor bleeding and partial dehiseence of the suture lines in two dogs and stenosis of the nasal orifice in one dog.
Evaluation of Canine‐Derived Fibrin Sealant as a Hemostatic Agent
Authors: WHEATON LYNN G. , GREENSHIELDS RANDY M. , MEYERS KENNETH , WARDROP K. JANE , MOORE MICHAEL
Published: February 2008

The purpose of this study was to determine whether canine‐derived fibrinogen concentrate applied with bovine thrombin was a safe and effective topical hemostatic agent. A canine liver biopsy model was selected to test this product. Cryoprecipitate was prepared from frozen canine plasma using two freeze/thaw/centrifugation cycles. Six healthy adult dogs (weighing more than 18 kg) were used in the fibrin sealant study, and an additional three dogs were used as controls for the liver biopsy. A 1 × 3 cm liver biopsy specimen was obtained, digital pressure was applied to reduce bleeding, and the fibrinogen concentrate was immediately sprayed on the bleeding surface simultaneously with bovine thrombin (1,000 IU/mL). The mean ± standard error of the mean (SEM) blood pressure at time of biopsy was 98 ± 9 mm Hg, and the rate of hemorrhage from the cut liver edge was 8.0 ± 1.1 mL/min. The total blood loss during fibrin sealant application was 37 ± 9 mL and total time for hemostasis was 5.5± 1.3 minutes. There was no additional hemorrhage after application of the fibrin sealant. In the three control dogs, fibrin sealant was not applied and only digital compression was used to decrease hemorrhage. Before digital compression, the rate of hemorrhage from the cut liver edge was 13.1 ±3.1 mL/min. Bleeding had not stopped after 10 minutes of compression and the mean postcompression rate of hemorrhage was 4.0 ± 2.6 mL/min. Signs of secondary bleeding after fibrin sealant was applied were not evident during the immediate postoperative period or over the next 14 days. The coagulation profile, alanine amino transferase (ALT), alkaline phosphatase (AP), and bile acids were not significantly different on day 14 from preoperative values, suggesting that the liver was only mildly affected. The dogs were euthanatized and gross and histological examinations of the biopsy site were performed on day 14. There were minimal or no adhesions at the biopsy site. In all dogs, the hepatic capsule was less than 1 mm thick and histological signs of secondary bleeding, hepatocellular damage, thrombosis, infection, or inflammation were not observed. In this study, canine‐derived fibrin sealant was a safe and effective topical hemostatic agent.
Equine Demineralized Bone Matrix: Relationship Between Particle Size and Osteoinduction
Authors: VAIL TIMOTHY B. , TROTTER GAYLE W. , POWERS BARBARA E.
Published: February 2008

The osteoinductive capability of four particle sizes of equine demineralized bone matrix (DBM) was evaluated. Matrix particles were implanted in brachiocephalicus muscle pouches in six horses and were harvested 8 weeks later. Matrix particle sizes of 2.0 mm3 to 4.0 mm3 and 5.0 mm3 to 10.0 mm3 were associated with osteoinductive activity and minimal signs of local inflammation. The two smaller particle sizes (0.425 mm3 to 0.850 mm3 and 0.850 mm3 to 2.0 mm3) were minimally osteoinductive and were associated with a greater local inflammatory response. Microscopic events associated with new bone production in the two largest particle sizes included the presence of new osteoprogenitor cells in matrix vascular spaces, multinucleated osteoclast‐like giant cells, and the formation of cartilage, osteoid, and new mineralized bone. The two smaller particle sizes were associated with increased fibrous tissue ingrowth and the presence of increased numbers of inflammatory cells. The temporal events of osteoinduction in response to heterotopic implantation of allogeneic DBM were delayed in horses when compared with other species. Although the demineralization technique used was effective in previous investigations on other species, incomplete demineralization occurred in the two smaller particle sizes that was not detected until after DBM implant harvest. The demineralization process may need to be altered for equine bone and precise monitoring for complete demineralization before implantation is required. Equine DBM is osteoinductive in muscle pouch sites in horses but matrix particle size does affect osteoinductive capability.
Effects of 0.05% Chlorhexidine Lavage on the Tarsocrural Joints of Horses
Authors: WILSON DAVID G. , COOLEY JAMES , MACWILLIAMS PETER S. , MARKEL MARK D.
Published: February 2008

In six horses, a 0.05% solution of chlorhexidine diacetate was used to lavage one tarsocrural joint; the contralateral control joint was lavaged with lactated Ringer's solution. Horses were evaluated daily for lameness. Synovial fluid samples were collected on days 1, 4, and 8 for determination of protein concentration, total and differential leukocyte counts, and mucin clot formation. After death on day 8, synovium and osteochondral samples were collected from the tarsocrural joints for examination of morphology and proteoglycan staining. Lavage with chlorhexidine solution caused lameness that was reduced but still evident at day 8. Synovial protein concentration was significantly increased by chlorhexidine lavage; the greatest increase occurred on day 1. Joint lavage increased synovial leukocyte counts on day 1, primarily by increasing polymorphonuclear (PMN) cell counts. Although total synovial leukocyte counts returned to normal by day 4, PMN cell counts remained elevated through day 8; PMN cell counts for chlorhexidine‐lavaged joints were typically twice that of control joints. Chlorhexidine lavage caused synovial ulceration, inflammation, and abundant fibrin accumulation. Consistent differences in proteoglycan staining were not detected between control and chlorhexidine‐lavaged joints. Joint lavage with 0.05% chlorhexidine diacetate, the lowest known bactericidal concentration, is not recommended for equine joints.
Comparison of a Biofragmentable Intestinal Anastomosis Ring With Appositional Suturing for Subtotal Colectomy in Normal Cats
Authors: HUSS BRIAN T. , PAYNE JOHN T. , JOHNSON GAYLE C. , WAGNER‐MANN COLETTE C.
Published: February 2008

A subtotal colectomy was performed on 12 normal adult cats using an interrupted apposing suture pattern of monofilament polyglyconate (n = 6) or a biofragmentable intestinal anastomosis ring (Valtrac, Davis and Geek Company, Danbury, CT) (n = 6) composed of polyglycolic acid and barium sulfate. Abdominal radiographs were made daily, beginning 10 days after surgery, to determine fragmentation rates of the anastomosis ring. The cats were euthanatized 30 days after surgery, and a gross and histopathological evaluation of anastomotic healing and stricture formation was performed. The technique for implantation of the anastomosis ring was easy to learn and required only two purse string sutures to complete. Intraoperative complications associated with the anastomosis ring were minor, and included problems with purse string suture placement, small serosal tears, and spasms of the colon that reduced the lumenal diameter. There were no intraoperative complications in the cats with sutured anastomoses. Postoperative recovery was uneventful in all cats. The anastomosis rings fragmented 12.2 ± 1.1 days (mean ± standard deviation [SD]) after implantation and passed in the stool 3.8 ± 1.9 days later without clinical signs in five of six cats. There were no statistically significant differences between the time required to perform the anastomosis (P= .348), postmortem gross anastomosis grades (P= .088), or percent of lumenal stricture (P= .178) between the two groups. Histologically, the only significant differences were an increased muscular inversion in the anastomoses performed using the fragmentable ring (P= .039) and an increased muscular eversion in the sutured anastomoses (P < .001) compared with normal colonic architecture.
The Anatomic Basis of a Free Vascularized Bone Graft Based on the Canine Distal Ulna
Authors: SZENTIMREY DAVID , FOWLER DAVID
Published: February 2008

The anatomy of the canine distal ulna was evaluated to determine its potential as a free vascularized bone graft. Twelve cadavers were studied by gross dissection and nonselective and selective angiography. The caudal interosseous artery consistently served as a source artery to the distal ulnar periosteal vasculature in all dogs. The diameters of the caudal interosseous artery and venae comitantes were large enough to permit microvascular anastomoses. Nonselective perfusions of the brachial artery demonstrated large barium‐filled vessels within soft tissues surrounding the ulna with anastomotic connections between medullary and periosteal vasculature. Grafts selectively perfused through the caudal interosseous artery (periosteal circulation only) had barium‐filled vessels within the muscular cuff, periosteum, cortical bone, and medullary canal of the ulna. A surgical approach to remove the distal ulna along with an intact musculoperiosteal cuff and its associated vasculature is described.
Wound Healing and Brain Stem Auditory Evoked Potentials After Experimental Total Ear Canal Ablation With Lateral Tympanic Bulla Osteotomy in Dogs
Authors: MCANULTY J. F. , HATTEL A. , HARVEY C. E.
Published: February 2008

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.