Measurement of Muscle Surface Capillary Blood Flow by Laser Doppler Flowmetry

Muscle surface capillary blood flow was measured in the biceps femoris and lateral head of the triceps brachii muscles in six horses before and during halothane anesthesia by using laser Doppler flowmetry. During 90 minutes of anesthesia, muscle surface capillary blood flow was reduced to 20% to 40% of preanesthetic values. Muscle surface capillary blood flow tended to be lower in dependent muscles than in nondependent muscles, and this disparity was greater in the forelimbs than in the hind limbs.     

Distraction Osteogenesis Using Modified External Fixation Devices in Five Dogs

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

The Effects of Fixation of the Ulna to the Radius in Young Foals

The effects of radioulnar fixation were studied in 21 Quarter horse foals by applying a bone plate to the caudal aspect of the proximal part of the ulna, with screws engaging both the radius and the ulna. The plates were applied at 1 month of age in six foals (group I), 5 months of age in six foals (group II), and 7 months of age in three foals (group III). Six foals underwent sham operations at 1 month of age to serve as controls (group IV). Ulnar dysplasia and elbow subluxation developed in all treated foals. The magnitude of ulnar dysplasia was inversely related to the patient's age at fixation and was accompanied by degenerative joint disease and lameness in foals undergoing fixation at 1 and 5 months of age. Removal of the fixation appliances 16 weeks after implantation in three foals from each of groups I and II failed to reverse the degree of ulnar dysplasia. Although foals undergoing fixation at 7 months of age (group III) were not lame, radiographic evidence of subluxation and subtle degenerative changes in the articular cartilage of the treated elbow did develop. Recommendations for avoidance of radioulnar fixation were developed from these observations.     

Feline Ilial Fractures: A Prospective Study of Dorsal Plating and Comparison with Lateral Plating

Objective— To (1) report a technique for repair of feline ilial fractures using a dorsally applied bone plate and (2) compare outcome with cats treated by a lateral plate.
Study Design— Prospective study.
Animals— Cats (n=10) with iliac fractures.
Methods— Cats with ilial fractures (January 2005–December 2006) were treated by application of a dorsally applied bone plate. Immediate postoperative radiographs were compared with those taken 4–6 weeks later to assess screw loosening, screw purchase, and pelvic canal narrowing. Owners were contacted for medium-term (>3 month) follow-up. Data were compared with a report of outcome after lateral plating (LP) in 21 cats.
Results— Mean (± SD) screw purchase (89 ± 11 mm) was significantly greater ( P <.01) with a dorsal plate compared with a lateral plate (33 ± 8 mm). Significantly more screws ( P <.01) were used with a dorsal plate (median, 7) compared with a lateral plate (median, 6). Significantly less postoperative pelvic canal narrowing developed in the dorsal plating group between postoperative and 4–6-week follow-up radiography compared with the LP group (2% versus 15%, P <.01).
Conclusion— Dorsal plating of feline ilial fractures results in significantly less screw loosening and pelvic canal narrowing at 4–6 weeks after surgery compared with LP.
Clinical Relevance— Dorsal plating of feline iliac fractures may reduce complications associated with pelvic canal narrowing such as constipation and megacolon.     

Equine Post-anesthetic Lameness A Retrospective Study

The incidence of post-anesthetic lameness in 655 horses undergoing 733 anesthetic episodes over a 3 year period was 6.4%. Nineteen factors previously reported or proposed to play a role in the development of post-anesthetic lameness were evaluated statistically. Only hypotension and the duration of the anesthetic period were significant factors.     

Evaluation of the Tibia as a Source of Autogenous Cancellous Bone in the Horse

A 1 cm defect was created in the proximal medial cortex of 12 tibiae, cancellous bone was removed from the site, and the bones were fractured by loading in torsion. The fractures did not occur through the donor sites and the fracture patterns and loads to fracture were similar for the treated tibiae and their untreated mates. Cancellous bone was harvested from the proximal medial aspect of both tibiae in nine adult horses. The soft tissue wounds were monitored for more than 10 days in seven horses and healing of the osseous defects was evaluated radiographically at regular intervals to month 6 in two horses. The site provided convenient access with the horses in lateral or dorsal recumbency, the anatomic landmarks were reliable, and the surgical procedure was simple and short. Complications occurred in only three incisions.     

Long-Term Follow-up of Partial Limb Amputation in 13 Horses

Thirteen cases of partial limb amputation in horses were reviewed. Nine horses (69%) survived 18 to 111 months (mean, 41 months). Four unsuccessfully treated horses were euthanatized within 21 days of surgery. The horses' ages at amputation were 4 to 13 years (mean, 7.3 years). There was no predilection for the left or right limb nor for fore or hind limb involvement. Osteomyelitis in six horses (46%) was the most common cause for amputation. Severe, open, comminuted fractures of the third metacarpal bone that were impossible to stabilize by any currently available technique in four horses (31%) were the second most common cause for amputation. One gelding was salvaged because of his sentimental value, two horses were used as breeding stallions, and six were broodmares. One stallion lived 30 months, completed two breeding seasons, and started a third. The other stallion began breeding, but became sterile. Three of the mares have produced five foals. One mare died while in foal. One mare aborted near-term twin fetuses and died of uterine hemorrhage. One mare aborted twice before the femoral head ligament on the contralateral limb ruptured, and she was euthanatized.     

DETERMINATION OF T1 RELAXATION TIME OF NORMAL EQUINE TENDONS USING MAGIC ANGLE MAGNETIC RESONANCE IMAGING

Seven isolated equine front limbs were used to establish the normal T1 relaxation time of equine superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), and suspensory ligament (SL) using magic angle magnetic resonance (MR) imaging. MR imaging of the metacarpi was performed with the limbs positioned at 55° (the magic angle) relative to the main magnetic field. Transverse spin‐echo proton density and inversion recovery images were acquired. T1 relaxation time was calculated based on ratios of signal intensity determined from the different pulse sequences. T1 relaxation times for SDFT, DDFT, and SL were 288 (±17), 244 (±14), and 349 (±16) ms, respectively. The difference in T1 values between SDFT, DDFT, and SL was statistically significant. T1 values of equine tendons can be determined with magic angle imaging on a clinical MR system using <10 min total scan time. The knowledge of the normal range of T1 values may be useful to identify horses with chronic tendinopathy, where based on the human literature, an increased T1 value may be expected.     

Complications of Celiotomy Incisions in Horses

Complications of celiotomy incisions were evaluated retrospectively in 274 horses that survived at least 1 month after surgery, or died or were euthanatized within 1 month of surgery, as a direct result of these complications. Horses were divided into four groups; group A, a ventral median celiotomy for intestinal disease; group B, ventral median celiotomy for nonintestinal disease; group C, repair of an umbilical hernia; and group D, celiotomy in a region other than the midline. Specific incisional complications were peri-incisional edema, drainage, incisional abscess, suture sinus, and dehiscence. Incision-related complications occurred in 30% of the horses (group A, 40%; group B 18%; group C, 7%; and group D, 88%). Complications occurred more frequently in group D than group A ( P =.009), which were higher than in groups B and C ( P <.00001). Incisional hernia occurred in 28 of 256 (11%) horses that survived at least 4 months and were available for follow-up. Hernia formation was more common ( P <.00001) in horses that had other incisional complications (23 horses) than those without (5 horses). Serous or purulent incisional drainage, were more likely to be associated with hernia formation than was serosanguineous drainage or other incisional complications.     

Evaluation of Canine-Derived Fibrin Sealant as a Hemostatic Agent

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.