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Objective: To determine the effect of surgical technique and use of a rigid centralizing device on stem positioning and geometric reconstruction in the sagittal plane during total hip replacement in dogs., Sample Population: Bilateral femurs from 8 adult mixed-breed canine cadavers., Procedure: Femurs were prepared for femoral stem implantation, using 4 variations in technique. Proximal femoral reconstruction and femoral stem positioning were evaluated on radiographs., Results: Implants evaluated in this study accurately reconstructed displacement of the femoral head of the intact canine femur in the sagittal plane. Centralization of the distal aspect of the stem was optimized by use of an undersized femoral stem. Ostectomy at the level of the lesser trochanter resulted in the smallest diaphysis-to-implant angle. Anteversion and retroversion of implants significantly decreased the distance between the distal tip of the implant and the adjacent cortex, compared with normoversion. The centralizing device significantly increased the minimum distance between the distal tip of the implant and adjacent cortex but did not improve the odds of actually centralizing the tip of the implant., Conclusions and Clinical Relevance: Malpositioning of implants in the sagittal plane may be minimized through ostectomy at the lesser trochanter and use of an undersized implant positioned in normoversion. Use of a polymethylmethacrylate centralizing device will help eliminate contact between the implant tip and adjacent cortex. Implantation of an undersized femoral component, avoidance of substantial anteversion or retroversion, and use of a rigid centralizing device are recommended when using the prosthesis described-for total hip replacement of dogs.

Objective: To determine the outcome of total hip arthroplasty in canine hindlimb amputees., Study Design: Retrospective evaluation of clinical cases., Methods: Data recorded from the medical records of nine dogs included patient signalment, indication for amputation and total hip arthroplasty (THA), interval between amputation and THA, and surgical complications. Radiographs were used to assess implant orientation and evidence of complications. Functional outcome was assessed using direct patient evaluation by one of the authors or primary surgeons, or through telephone interview between the primary author and the owner., Results: Seven dogs ultimately had a good or excellent clinical results. Complications occurred in five dogs. Four dogs luxated the prosthetic joint without an obvious traumatic event within 9 weeks of the initial surgery. Revision surgeries resulted in successful coxofemoral reduction in three of four dogs. There were no clinical or radiographic findings suggestive of implant loosening or infection., Conclusion: THA can be a successful salvage procedure in the canine hindlimb amputee with disabling, non-neoplastic, noninfectious coxofemoral disease. The risk of luxation in the early postoperative period is high and revision surgery is required for stabilization.

Objectives: To test whether femoral ostectomy level, subtrochanteric bone mass removal, and stemsize selection significantly affect stem positioning in canine total hip replacement, and to determine ability of the femoral stem component to restore geometry of the normal femoral head and neck., Sample Population: Femurs from 8 adult mixed-breed canine cadavers., Procedure: Femurs were systematically prepared, using 8 combinations of 3 surgical preparation techniques that included level of ostectomy (cervical isthmus vs lesser trochanter), subtrochanteric bone block removal, and femoral stem size (recommended, undersized). Computer-aided analysis of specimen photographs was used to evaluate femoral head offset and position and variability of femoral stem positioning for each of the preparation combinations., Results: Original femoral head offset and position were reconstructed to within a mean of 0.052 and 0.031 cm, respectively, using an undersized femoral stem after ostectomy at the level of the lesser trochanter. Implantation of an undersized femoral stem after subtrochanteric bone block removal improved ability to centralize the distal tip of the implant and reduce the angle between the femoral diaphyseal and implant axes. Ostectomy at the level of the cervical isthmus tended to force femoral implants into a varus position, and ostectomy at the level of the lesser trochanter tended to force implants into a valgus position., Conclusions: Geometry of normal canine femurs was most closely reconstructed by implantation of an undersized femoral component after ostectomy at the level of the lesser trochanter. Implantation of an undersized femoral component after subtrochanteric bone block removal resulted in the best alignment and centralization of the stem.

Objective: To compare prospectively clinical, radiographic, and surgical findings of intervertebral disc extrusion (IDE) localization in small-breed dogs and to determine the best means of lesion localization for the purpose of hemilaminectomy., Study Design: Clinical, radiographic, and surgical findings of small-breed dogs with thoracolumbar IDE were prospectively compared for agreement on lesion localization., Sample Population: 50 small-breed dogs with IDE treated at the three participating veterinary hospitals were included in the study if no other confounding diseases were identified and if the owner gave permission for diagnostic tests and surgery., Methods: Clinical and surgical findings were recorded by the surgeon assigned to the case. Radiographic studies were evaluated independently by two radiologists blinded as to the clinical and surgical findings. kappa values and 95% confidence intervals were calculated for agreement on lesion localization by clinical, radiographic, and surgical means and for agreement between radiologists., Results: kappa values for agreement of lesion localization were as follows: clinical versus surgical, 0.595; radiologist A versus radiologist B, 0.81; radiologist A versus surgical findings, 0.60; radiologist B versus surgical findings, 0.71. Both radiologists' interpretation of IDE localization agreed with surgical localization in 60% of cases., Conclusions: Clinical lateralization of IDE was found to be the least reliable factor of those studied for determining on which side the hemilaminectomy should be performed. Results of this study differ from those of previous studies examining the reliability of myelography to localize the site of IDE accurately. The results of this study further suggest that surgery may not be an absolute standard for determination of the localization of IDE in small-breed dogs., Clinical Relevance: Intervertebral disc extrusion in small-breed dogs frequently results in bilateral distribution of extruded material. Computed tomography or magnetic resonance imaging may be necessary to delineate completely the distribution of extruded disc material in IDE.

Objective: The purpose of this report was to determine the efficacy of the application of ventral pins and polymethylmethacrylate for the management of congenital and traumatic atlantoaxial instability (AAI) in dogs., Study Design: Medical records and radiographs of nine dogs with AAI were reviewed for neurological deficits, clinical diagnosis, surgical technique, and long-term outcome., Sample Population: Six toy breed dogs with congenital AAI and three medium or large breed dogs with traumatic AAI were identified for inclusion in the study., Methods: The atlantoaxial joints of nine dogs with AAI were surgically stabilized using ventral application of pins and polymethylmethacrylate. Follow-up evaluation for resolution of clinical signs and possible complications of surgery was performed in all dogs. The median follow-up time for surviving dogs (8) was 11.5 months with a mean of 13 months., Results: An excellent outcome was identified in five patients. Three dogs had a good outcome and one dog died of respiratory complications. Cervical pain was eliminated or significantly reduced in all dogs that survived and none of the dogs had major residual neurological deficits., Conclusions: Arthrodesis could not be confirmed on follow-up radiographs due to the presence of the polymethylmethacrylate; however, adequate stabilization of C1-C2 appears to have been achieved based on the resolution of clinical signs., Clinical Relevance: Application of ventral pins and polymethylmethacrylate is an effective means of surgical treatment for congenital and traumatic AAI.

Objective: To study biomechanical characteristics of the normal and surgically altered canine thoracolumbar vertebral column to determine the effects of surgery and trauma on lateral stability., Animals: The T13-L1 vertebral motion units of 48 mixed-breed dogs were dissected free of surrounding musculature and prepared for biomechanical testing by cross-pinning the vertebral bodies and mounting in polymethylmethacrylate., Procedure: Normal and surgically altered spinal specimens were subjected to lateral bending. The mean slope of the bending moment versus angular displacement curve and the load to failure were compared between treatment groups and significance was determined by the method of least squares (P < 0.05). Specimens were surgically altered by facetectomy, lateral fenestration, diskectomy, and combinations of these procedures. Each specimen was subjected to lateral bending to failure at a rate of 2.5 cm/min in a swing arm bending jig designed to simulate 4-point bending and subject the specimen to pure bending., Results: Only specimens undergoing diskectomy had a significant decrease in slope and load at failure. Unilateral and bilateral facetectomies and fenestration induced a nonsignificant decrease in stiffness, compared with control specimens., Conclusions: Fenestrations and facetectomies do not appear to increase the risk of injury to the canine thora-columbar spinal cord during lateral bending., Clinical Relevance: Fenestrations and facetectomies, as used in routine laminectomies, may be performed without concern for significant destabilization of the spine in lateral bending; however, it is possible that thoracolumbar spinal fractures involving only the vertebral body may significantly destabilize the spine in all modes of bending.

Neurocysticercosis was diagnosed in a 2-year-old spayed Whippet by use of magnetic resonance imaging. The dog was evaluated because of a 3-month history of slowly progressive balance and directional abnormalities, which were indicative of brain stem disease. Magnetic resonance imaging of the brain and CSF analysis were chosen as the best diagnostic modalities for determination of the primary disease. Results of CSF analysis were within reference ranges. Examination of T1-weighted, contrast-enhanced, 3-mm-thick axial, sagittal, and coronal views of the brain revealed multiple cyst-like lesions. The cysts had high-signal-intensity, ring-like peripheral margins and were located in the subdural portion of the left occipital lobe and the dorsal midline and right dorsolateral aspect of the brain stem. A tentative diagnosis of neurocysticercosis was made on the basis of similar findings in human beings with this disease. Treatment with albendazole and prednisone was initiated, and clinical signs resolved during the following weeks. Repeat magnetic resonance imaging confirmed resolution of the disease.

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.

Escherichia coli bacteremia was detected in a dog that had hypertrophic osteodystrophy. The dog improved after treatment with cephalothin sodium, iv fluid therapy, and cage rest. The cause of hypertrophic dystrophy has not been determined, although an infectious cause has been suggested. Dogs that are suspected of having hypertrophic osteodystrophy should be monitored closely for evidence of septicemia, and the administration of prophylactic antibiotics may be advisable.

An 8-year-old mare was presented to the New York State College of Veterinary Medicine Large Animal Clinic for evaluation of anorexia, fever and icterus. The mare had a 5-day history of anorexia, depression and tongue protrusion. Diagnostic procedures included serum hepatic enzyme activities, serum bile acid concentrations, blood ammonia evaluations and hepatic ultrasound and ultrasound guided biopsy. The history, clinical pathology and histopathology in this case supported a probable diagnosis of primary septic cholangiohepatitis.