Modification of the contact area of a standard force platform and runway for small breed dogs.

OBJECTIVES: To develop a platform that used standard size force plates for large breed dogs to capture ground reaction force data from any size dog. METHODS: A walkway platform was constructed to accommodate two force plates (60 cm x 40 cm) positioned in series to a variety of smaller sizes. It was constructed from a custom wood frame with thick aluminium sheet force plate covers that prevented transfer of load to the force plate, except for rectangular windows of three different dimensions. A friction study was performed to ensure plates did not translate relative to one another during gait trials. A prospective, observational, single crossover study design was used to compare the effect of force platform configuration (full plate size [original plate], half plate size [modified plate]) on ground reaction forces using eight adult healthy Labrador Retriever dogs. RESULTS: Slippage of the steel plate on the force plate did not occur. Peak propulsion force was the only kinetic variable statistically different between the full size and half sized platforms. There were no clinically significant differences between the full and half force platforms for the variables and dogs studied. DISCUSSION AND CONCLUSION: The modified force platform allows the original 60 x 40 cm force plate to be adjusted effectively to a 30 x 40 cm, 20 x 40 cm and 15 x 40 cm sized plate with no clinically significant change in kinetic variables. This modification that worked for large breed dogs will potentially allow kinetic analysis of a large variety of dogs with different stride lengths.

The influence of esomeprazole and cisapride on gastroesophageal reflux during anesthesia in dogs.

BACKGROUND: Gastroesophageal reflux (GER) is common in anesthetized dogs and can cause esophagitis, esophageal stricture, and aspiration pneumonia. OBJECTIVE: To determine whether preanesthetic IV administration of esomeprazole alone or esomeprazole and cisapride increases esophageal pH and decreases the frequency of GER in anesthetized dogs using combined multichannel impedance and pH monitoring. ANIMALS: Sixty-one healthy dogs undergoing elective orthopedic surgery procedures. METHODS: Prospective, randomized, placebo-controlled study. Dogs were randomized to receive IV saline (0.9% NaCl), esomeprazole (1 mg/kg) alone, or a combination of esomeprazole (1 mg/kg) and cisapride (1 mg/kg) 12-18 hours and 1-1.5 hours before anesthetic induction. An esophageal pH/impedance probe was utilized to measure esophageal pH and detect GER. RESULTS: Eight of 21 dogs in the placebo group (38.1%), 8 of 22 dogs in the esomeprazole group (36%), and 2 of 18 dogs in the combined esomeprazole and cisapride group (11%) had ≥ 1 episode of GER on impedance testing during anesthesia (P < .05). Esomeprazole was associated with a significant increase in gastric and esophageal pH (P = .001), but the drug did not significantly decrease the frequency of GER (P = .955). Concurrent administration of cisapride was associated with a significant decrease in the number of reflux events (RE) compared to the placebo and esomeprazole groups (P < .05). CONCLUSIONS AND CLINICAL RELEVANCE: Preanesthetic administration of cisapride and esomeprazole decreases the number of RE in anesthetized dogs, but administration of esomeprazole alone was associated with nonacid and weakly acidic reflux in all but 1 dog.

Effects of trial repetition, limb side, intraday and inter-week variation on vertical and craniocaudal ground reaction forces in clinically normal Labrador Retrievers.

OBJECTIVES: To document the contributions of trial repetition, limb side, and intraday and inter-week measurements on variation in vertical and craniocaudal ground reaction force data. METHODS: Following habituation, force and time data were collected for all four limbs of seven Labrador Retrievers during sets of five valid trot trials. Each set was performed twice daily (morning and afternoon), every seven days for three consecutive weeks. A repeated measures analysis of variance was used to determine the effects of limb, trial, intraday, and inter-week factors on ground reaction force data for the thoracic and pelvic limbs. RESULTS: Of the four factors evaluated, variation due to trial repetition had the largest magnitude of effect on ground reaction forces. Trial within a set of data had an effect on all craniocaudal, but not vertical, ground reaction force variables studied, for the thoracic limbs. The first of five trials was often different from later trials. Some thoracic limb and pelvic limb variables were different between weeks. A limb side difference was only apparent for pelvic limb vertical ground reaction force data. Only pelvic limb craniocaudal braking variables were different between sets within a day. DISCUSSION AND CLINICAL SIGNIFICANCE: When controlling for speed, handler, gait, weight and dog breed, variation in ground reaction forces mainly arise from trial repetition and inter-week data collection. When using vertical peak force and impulse to evaluate treatment, trial repetition and inter-week data collection should have minimal effect of the data.

Skin movement during the kinematic analysis of the canine pelvic limb.

OBJECTIVES: To determine whether the canine pelvic limb can be considered a linkage of rigid bodies during kinematic analysis. METHODS: The lengths of the femur and tibia based on skin markers were examined throughout gait cycles in six dogs trotting on a treadmill at 2 m/sec. The angular kinematics of the hip, stifle and tarsal joints were calculated based on a conventional stifle marker (CSM) and computed virtual stifle positions (VSP). Based on the CSM and VSP, the kinematic data from the joints were compared and the agreement among them determined. The difference between the CSM and VSP coordinates were illustrated. RESULT: The femoral and tibial lengths based on skin markers were not constant throughout a gait cycle and the lengths changed in repeatable patterns in each dog. There was close agreement between the joint angles based on the CSM and VSP in the tarsal joint but not in the hip and stifle joints, where the kinematics based on the CSM tended to calculate smaller angular excursion than the kinematics based on VSP. The pattern of displacement of the CSM was repeatable through a gait cycle. CLINICAL RELEVANCE: There was skin movement which causes considerable artifact during kinematic analysis of the canine pelvic limb. The skin movement has to be accounted for during canine kinematic analysis.

Complications and radiographic findings following cemented total hip replacement: a retrospective evaluation of 97 dogs.

Cemented total hip replacement (cTHR) is commonly performed to treat intractable coxofemoral pain in dogs. While owners generally perceive a good outcome after the procedure, the longevity of the implant may be limited by complications such as infection and aseptic loosening. The objective of this retrospective study was to identify the prevalence of complications and radiographic changes following cTHR, and to identify factors that may predispose to a need for revision surgery. Medical records and radiographs from 97 dogs that underwent cTHR were evaluated for signalment, preoperative degree of osteoarthritis, technical errors, intra-operative culture results, and the post-operative radiographic appearance of the implant. The complications occurring in the intra-operative and short-term (eight week) time period were recorded. Mean (+/- SD) follow-up time was 1.1 +/- 1.6 years (range: 0-7.7 years). Seven dogs had a short-term complication and a revision surgery was performed in eleven dogs. Osseous or cement changes were radiographically detectable in the majority of cTHR. Eccentric positioning of the femoral stem and the presence of radiolucent lines at the femoral cement-bone interface were positively associated with the occurrence of revision surgery. The clinical significance of the periprosthetic radiographic changes is unclear and further investigation is warranted.

Photodynamic therapy with motexafin lutetium for rectal cancer: a preclinical model in the dog.

PURPOSE: Local recurrence of rectal cancer remains a significant clinical problem despite multi-modality therapy. Photodynamic Therapy (PDT) is a cancer treatment which generates tumor kill through the production of singlet oxygen in cells containing a photosensitizing drug when exposed to laser light of a specific wavelength. PDT is a promising modality for prevention of local recurrence of rectal cancer for several reasons: tumor cells may selectively retain photosensitizer at higher levels than normal tissues, the pelvis after mesorectal excision is a fixed space amenable to intra-operative illumination, and PDT can generate toxicity in tissues up to 1 cm thick. This study evaluated the safety, tissue penetration of 730 nm light, normal tissue toxicity and surgical outcome in a dog model of rectal resection after motexafin lutetium-mediated photodynamic therapy. METHODS: Ten mixed breed dogs were used. Eight dogs underwent proctectomy and low rectal end to end stapled anastomosis. Six dogs received the photosensitizing agent motexafin lutetium (MLu, Pharmacyclics, Inc., Sunnyvale, CA) of 2 mg/kg preoperatively and underwent subsequent pelvic illumination of the transected distal rectum of 730 nm light with light doses ranging from 0.5 J/cm(2) to 10 J/cm(2) three hours after drug delivery. Two dogs received light, but no drug, and underwent proctectomy and low-rectal stapled anastomosis. Two dogs underwent midline laparotomy and pelvic illumination. Light penetration in tissues was determined for small bowel, rectum, pelvic sidewall, and skin. Clinical outcomes were recorded. Animals were sacrificed at 14 days and histological evaluation was performed. RESULTS: All dogs recovered uneventfully. No dog suffered an anastomotic leak. Severe tissue toxicity was not seen. Histological findings at necropsy revealed mild enteritis in all dogs. The excitation light penetration depths were 0.46 +/- 0.18, 0.46 +/- 0.15, and 0.69 +/- 0.39 cm, respectively, for rectum, small bowel, and peritoneum in dogs that had received MLu. For control dogs without photosensitizer MLu, the optical penetration depths were longer: 0.92 +/- 0.63, 0.67 +/- 0.10, and 1.1 +/- 0.80 cm for rectum, small bowel, and peritoneum, respectively. CONCLUSION: Low rectal stapled anastomosis is safe when performed with MLu-mediated pelvic PDT in a dog model. Significant tissue penetration of 730 nm light into the rectum and pelvic sidewall was revealed without generation of significant toxicity or histological sequelae. Penetration depths of 730 nm light in pelvic tissue suggest that microscopic residual disease of less than 5 mm are likely to be treated adequately with MLu-mediated PDT. This approach merits further investigation as an adjuvant to total mesorectal excision and chemoradiation for rectal cancer.

Pullout properties of 3.5-mm AO/ASIF self-tapping and cortex screws in a uniform synthetic material and in canine bone.

OBJECTIVES--To compare the pullout properties of 3.5-mm AO/ASIF self-tapping screws (STS) to corresponding standard cortex screws (CS) in a uniform synthetic test material and in canine femoral bone. The influence of screw-insertion technique, test material, and test-material thickness were also assessed. STUDY DESIGN--In vitro experimental study. SAMPLE POPULATION--Two independent studies: a uniform synthetic test material and paired femurs from mature dogs. METHODS-Mechanical testing was performed in accordance with standards established by the American Society for Testing and Materials for determination of axial pullout strength of medical bone screws. Completely inserted STS, completely inserted CS, and incompletely inserted STS were tested in 3 groups of 10 test specimens each in 4.96-mm and 6.8-mm thick sheets of synthetic material. In the bone study, group 1 consisted of 24 completely inserted STS compared with 24 completely inserted CS, and group 2 consisted of 24 incompletely inserted STS versus 24 completely inserted CS. Comparisons were made between paired femurs at corresponding insertion sites. Pullout data were normalized, thereby eliminating the effect of test-material thickness on pullout properties. Mean values were compared using 2-way ANOVA. Statistical significance was set at P <.05. RESULTS--In both the 4.96-mm and 6.8-mm synthetic material, pullout testing of the completely inserted STS demonstrated significantly greater yield strength and ultimate strength than completely inserted CS. There was no significant difference between incompletely inserted STS and completely inserted STS. The 6.8-mm test material significantly increased yield strength and ultimate strength for all test groups compared with the 4.96-mm test material. In canine bone, there was no significant difference in yield strength of completely inserted STS and completely inserted CS. Yield strength of completely inserted STS and completely inserted CS were significantly greater than incompletely inserted STS. CONCLUSIONS--Pullout properties of completely inserted STS were significantly greater than corresponding CS in a uniform test material. In canine bone, the pullout strength of STS and CS were not different. Incomplete STS insertion resulted in an 18% reduction in holding power as compared with completely inserted CS and STS in canine bone. CLINICAL RELEVANCE--The length of STS used in canine bone should be such that the cutting flutes extend beyond the trans cortex to maximize pullout strength.

Evaluation of risk factors for degenerative joint disease associated with hip dysplasia in German Shepherd Dogs, Golden Retrievers, Labrador Retrievers, and Rottweilers.

OBJECTIVE: To determine whether age, breed, sex, weight, or distraction index (DI) was associated with the risk that dogs of 4 common breeds (German Shepherd Dog, Golden Retriever, Labrador Retriever, Rottweiler) would have radiographic evidence of degenerative joint disease (DJD) associated with hip dysplasia. DESIGN: Cross-sectional prevalence study. ANIMALS: 15,742 dogs. PROCEDURE: Hips of dogs were evaluated radiographically by use of the ventrodorsal hip-extended view, the compression v ew, and the distraction view. The ventrodorsal hip-extended view was examined to determine whether dogs had DJD. For each breed, a multiple logistic regression model incorporating age, sex, weight, and DI was created. For each breed, disease-susceptibility curves were produced, using all dogs, regardless of age, and dogs grouped on the basis of age. RESULTS: Weight and DI were significant risk factors for DJD in all breeds. For German Shepherd Dogs, the risk of having DJD was 4.95 times the risk for dogs of the other 3 breeds combined. In all breeds, the probability of having DJD increased with age. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the probability of having hip DJD increased with hip joint laxity as measured by use of DI. This association was breed-specific, indicating that breed-specific information on disease susceptibility should be incorporated when making breeding decisions and when deciding on possible surgical treatment of hip dysplasia.

Neurosurgical emergencies.

The neurologic patient is considered a neurosurgical emergency when delay of treatment may influence the patient's outcome. Diseases of the spinal cord, brain, and peripheral nerves are presented in this article. Diagnostic tools (i.e., advanced imaging and electrophysiologic tests), differential diagnoses, treatment options (conventional and controversial), whether the patient requires surgery, and the optimal time for surgical intervention are discussed.

Spinal tumors in 37 dogs: clinical outcome and long-term survival (1987-1994).

The current management of dogs with spinal canal neoplasia in a large veterinary institution was evaluated. Postoperative survival time and prognostic indicators for survival were examined. Spinal neoplasms in dogs and humans also were compared. Thirty-seven cases with histologically confirmed spinal tumors were included in the study. The cervical region was affected most commonly, and 23 (62%) of 37 cases had extradural tumors. A hemilaminectomy or a dorsal laminectomy was performed in each case; three cases received adjuvant treatment. Twelve (32%) cases were euthanized at the time of surgery, and two died immediately after surgery. One dog was euthanized 20 days after surgery because of persistent clinical signs. Twenty-two cases were followed postoperatively; nine different types of primary tumors were confirmed by histological examination of tissue specimens from these 22 cases, and three cases had metastatic lesions. The median survival time of these 22 cases was 240 days. Twelve (32%) of the 37 cases had nerve-sheath tumors; the median survival time for these 12 cases was 180 days. No prognostic indicators were identified. However, median survival times of cases with benign versus malignant tumor types were 1,410 days and 180 days, respectively (p of 0.07). Four cases each had a myxoma/myxosarcoma, a tumor previously unreported in the spinal canal in dogs.

Nonlymphoid vertebral canal tumors in cats: 11 cases (1987-1995).

OBJECTIVE: To determine outcome of cats with nonlymphoid tumors of the vertebral canal that undergo surgery. DESIGN: Retrospective study. ANIMALS: 11 cats. PROCEDURE: Information obtained from the medical records included signalment, tumor location, gross evaluation of completeness of surgical excision, histologic diagnosis, and survival time. RESULTS: Median age of cats was 12 years: all cats had negative FeLV and feline immunodeficiency virus test results. All cats underwent a hemilaminectomy or dorsal laminectomy. The tumor was located in the thoracic portion of the vertebral column in 6 cats. Six cats had intradural-extramedullary tumors. Tumors included meningioma (n = 5), malignant nerve sheath tumors (2), and meningeal sarcoma, chondrosarcoma, lipoma, and osteosarcoma (1 each). One cat was lost to follow-up, 1 cat with meningioma was alive 1,400 days after surgery, and 1 cat with a nerve sheath tumor was alive 2,190 days after surgery. Median survival time for the other 4 cats with meningioma was 180 days (range, 30 to 600 days). CLINICAL IMPLICATIONS: Cats with nonlymphoid vertebral canal tumors that undergo surgery may have a good prognosis.

Dental composite for the fixation of mandibular fractures and luxations in 11 cats and 6 dogs.

Twenty-one mandibular fractures in 11 cats and 6 dogs were repaired during a 20-month period. A new technique using dental composite was used to stabilize the mandible. The canine teeth were pumiced, acid etched, and aligned with dental composite, leaving the mouth opened approximately 1 cm. Six weeks after surgery the composite was removed so that radiographs of the mandible could be made with the animal under general anesthesia. In 1 dog in which the fracture had not healed, the composite was replaced. The composite broke before 6 weeks in 8 animals; 2 required replacement of the dental composite. There were no other complications. The median time for fracture healing was 6 weeks. All fractures healed with anatomic dental occlusion. The advantages of this technique are that no further damage is caused to the teeth or to the blood supply of the bone, the occlusion is anatomic, dermatitis (which is seen with tape muzzles) is not a complication, and the technique is easy to use in brachycephalic breeds, cats, and animals with poor bone quality. The limiting factor of this technique is that it does require four salvageable canine teeth. This repair technique is still a viable option even if one or more of the canine teeth are fractured. Dental composite stabilization is fast, easy, inexpensive, and, in our series, it was 100% effective for the repair of mandibular fractures.

Leiomyosarcoma in dogs: 44 cases (1983-1988).

During a 5-year period, leiomyosarcoma was diagnosed in 57 dogs. Forty-four dogs were included in the study on the basis of completeness of medical records. All dogs underwent exploratory laparotomy, and dogs were allotted to 4 groups according to primary site of tumor: spleen (16 dogs, median age 10.3 years), stomach/small intestine (13 dogs, median age 10.3 years), cecum (10 dogs, median age 11.8 years), and liver (5 dogs, median age 9 years). All dogs with leiomyosarcoma of the liver had visible metastasis and were euthanatized at surgery. In the other 3 groups, 79% of the dogs had no gross evidence of metastasis at surgery, and 64% survived greater than 2 weeks. Median survival in these 3 groups was 10 months (range, 1 month to 7 years); 48% died of metastasis, 32% died of unrelated causes, and 16% died of unknown causes. The prognosis in dogs with leiomyosarcoma of the spleen, stomach, small intestine, and especially the cecum is good to excellent if surgery is performed. In dogs with leiomyosarcoma of the liver, the prognosis is poor.

Problems associated with basic oral surgical techniques.

The veterinarian must be able to diagnose several types of dental problems. History, physical examination, clinical pathology, and radiography are important in making an accurate diagnosis. Basic oral surgery includes various extraction techniques and management of their associated complications. Knowledge of dental anatomy and proper surgical technique can make an extraction curative rather than a frustrating procedure with multiple complications.

Intraoperative problems associated with intervertebral disc disease.

Intervertebral disc disease in the dog is a common problem in veterinary medicine. The clinician must understand the pathophysiology of disc extrusions so the owner can be informed properly when medical versus surgical treatment is indicated. Intervertebral disc surgery requires the same preoperative considerations as any other surgery would: knowledge of regional anatomy, proper equipment, and good surgical techniques and tissue handling. The spinal cord is an unforgiving structure, forcing the surgeon to understand and to avoid intraoperative complications. Some complications are inevitable. Recognizing these complications early and resolving them quickly will help ease early recovery of neurologic function.