Preservation of Skin by Refrigeration for Autogenous Grafting in the Horse

Eighteen stored split thickness meshed skin grafts were applied to surgically created lesions on the metacarpal and metatarsal regions of six horses. Donor skin was harvested from the sternal region, meshed and stored at 4 degrees C in a cell culture medium containing 10% serum. Stored grafts were applied to the wounds at 1, 2, and 3 week intervals. Acceptance of the grafts stored for 1 week was generally poor (1 of 6 grafts), whereas that of the 2 and 3 week old grafts was generally excellent (10 of 12 grafts). Poor acceptance of the 1 week old grafts was attributed to streptococcal infection of the recipient wounds. Using the storage medium and grafting technique described, excellent acceptance can be expected after graft storage of up to 3 weeks.     

Dorsal Frontal Fractures of the First Phalanx in the Horse

Dorsal frontal fractures of the first phalanx in nine horses are described. All fractures were in hindlimbs, and two horses were affected bilaterally. Of the eleven fractures, seven were incomplete and nondisplaced, one was complete and nondisplaced, and three were complete and displaced. Two horses with complete displaced fractures had their fractures repaired with lag screw fixation combined with open reduction, and the other seven horses were treated nonsurgically.
All horses were sound on the injured limb within 3 to 6 months of the injury. Lag screw fixation was recommended for horses with complete, displaced dorsal frontal fractures in order to reduce the articular defect and help prevent secondary joint changes. Nonsurgical therapy in the form of stall rest with a heavy support wrap resulted in bony healing of the fracture in 4 to 6 months.
Follow-up was obtained on all nine horses: two were retired for breeding; five performed equal to or better than their previous level of racing performance; one was performing successfully as a combined training horse; and one returned to a lower level of performance due to an unrelated forelimb lameness.     

Osteochondral Dowel Transplantation for Repair of Focal Defects in the Knee: An Outcome Study Using an Ovine Model

Objective—A model system was developed to objectively assess the quality of articular cartilage after surgical reconstruction of focal defects in the medial femoral condyle using osteochondral dowel grafts.
Study Design—The surgical technique was developed and customized to reproducibly minimize surgical trauma and graft instability in order to improve the survival of the transplanted cartilage and the long-term integrity of the joint surfaces.
Animals or Sample Population—24 adult female Suffolk-Romanoff crossbred sheep.
Methods—Biomechanical creep testing, paravital staining for chondrocyte viability, histological analysis, and gross morphological analysis were performed at 3, 6, and 12 months postoperatively to compare fresh autografted osteochondral dowels with allografts that had been subject to a freezing protocol known to kill chondrocytes. The latter was used to investigate the time course of cartilage degeneration after injury. These two groups were also compared with normal unoperated control tissue.
Results—Biomechanical behavior, chondrocyte survival, and cartilage histology differed significantly between fresh grafts and those that had been frozen.
Conclusions —Indentation testing and paravital staining were able to identify degenerative changes earlier than other methods of assessment. The technique developed here reproducibly and reliably transplanted osteochondral dowel grafts while minimizing the confounding effects of surgical trauma and graft instability.
Clinical Relevance —The technique provides both a promising surgical technique for the repair of focal defects of the medial femoral condyle and a sensitive model for the future study of cryopreservation strategies for articular cartilage.     

INFLUENCE Of PATIENT POSITIONING ON THE L5–L6 MID-LAMINAR DISTANCE

The aim of this project was to determine the effect of patient position on the L5-L6 mid-laminar distance (MLD). The lumbar area of 22 recently euthanatized dogs of various breeds was radiographed in three positions: lateral recumbency with the spine in neutral position, lateral recumbency with the spine flexed in a kyphotic position, and sternal recumbency with the spine flexed in a kyphotic position. Digital images of the radiographs were analyzed using a computer program that allowed measurement of the MLD between L5-L6 in the three positions. The L5 and L6 MLD was significantly larger in sternal recumbency with the spine flexed (142.3 units) than both in lateral recumbency with the spine flexed (138.7 units; P= 0.001) and lateral recumbency with the spine in the neutral position (135.8 units; P < or = 0.001). The MLD in lateral recumbency with the spine flexed was significantly larger than in lateral recumbency with the spine in neutral position (P = 0.005). Positioning a dog in sternal recumbency with the spine flexed produces a significantly larger MLD than in lateral recumbency with the spine flexed; this should simplify needle placement when performing a lumbar puncture.     

Ventricular Arrhythmias in Dogs Undergoing Splenectomy: A Prospective Study

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.     

Ex Vivo Biomechanics of Kirschner-Ehmer External Skeletal Fixation Applied to Canine Tibiae

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.     

Low‐Income Dynamics in Canadian Communities: A Place‐Based Approach

ABSTRACT Canadian poverty rates have persisted at disappointingly high levels despite almost 15 years of continuous economic growth. The problem is exacerbated by some communities and neighborhoods having exceedingly high poverty, including very high rates for vulnerable demographic groups, such as aboriginals and recent immigrants. We investigate low‐income rates (poverty rates) for 2,400 Canadian “communities” over the 1981–2001 period. By focusing on communities, we fill a void in the related Canadian literature, which tends to focus on individuals, case studies, or more aggregate measures, such as provinces. Our approach allows us to assess the role of place‐based policies. Particular attention is given to communities with differing shares of aboriginal Canadians and recent immigrants. One novel feature is our analysis of both “short‐term” and “long‐term” causes of differential community poverty rates. The results suggest that community low‐income rates are more affected by initial economic conditions in the short term, with certain demographic factors becoming relatively more important in the long run.     

Mycobacterium avium infection in a dog

A 5-year old, spayed, mongrel was presented with intractable diarrhoea. Histopathologic examination of biopsy specimens taken during exploratory laparotomy revealed acid-fast organisms in the spleen, caecum, and colon. The dog was subsequently destroyed. At post-mortem, lesions were also observed in the liver and lymph nodes. Mycobacterium avium was cultured from splenic tissue. Infection of dogs with this organism is rare and the clinical picture described unusual.