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Objective: To evaluate the feasibility of endoscopic inspection of thoracolumbar and lumbar pedicle tracts in a canine large-breed model and its accuracy for the detection of breached versus nonbreached tracts., Animals: 2 greyhound cadavers., Methods: CT scans of 2 greyhound cadavers from the sixth thoracic vertebra to the sacrum were obtained. Fifty-six pedicles were randomized to have drill tracts with different modified Zdichavsky grades (nonbreached, partial/full medial breach, or partial/full lateral breach) using 3-D-printed guides. Endoscopy was performed on a single occasion from October 9 to 10, 2023, using a 1.9-mm 0-degree needle arthroscope in a randomized blinded fashion. The grading of drill tracts was performed on postoperative CT. Specificity, sensitivity, positive and negative predictive values, and time to assign endoscopic grade were investigated., Results: Postoperative CT confirmed 43 nonbreached tracts, 7 medial breaches (partial/full), and 5 lateral breaches (partial/full). One tract was excluded because of guide misplacement. Intraosseous endoscopy was successfully performed in the remaining 55 drill tracts. Sensitivity to detect medial and lateral breaches was 71.4% and 60.0%. Negative predictive value was 93.1%. Specificity was 94.2%. Positive predictive value for detection of medial and lateral breaches was 83.3% and 54.5%. Median (range) time to assign an endoscopic grade was 118 (30 to 486) seconds., Clinical Relevance: Intraosseous endoscopy of pedicle drill tracts may be a useful adjunct technique during pedicle screw/pin placement in dogs.

Objective: To evaluate the efficacy of combined administration of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF-I) on the regeneration of transected and anastomosed sciatic nerves., Animals: 25 male Lewis rats., Procedure: Transection and anastomosis was performed of the left sciatic nerve of all rats. At the time of surgery, treatment group rats received a combination of PDGF (0.75 microgram) and IGF-I (1.5 micrograms) along with vehicle (2% methyl cellulose gel) at the anastomosis site. Control rats received vehicle alone. Evaluation consisted of motor evoked potentials and nerve conduction velocity, quantitative histologic examination, sciatic functional index, and visual assessment of repair organization (lesion scores)., Results: Significant differences in motor evoked potential latency, nerve conduction velocity, axon number, sciatic functional index, or lesion scores were not found between groups., Conclusions: Combined administration of PDGF and IGF-I did not enhance peripheral nerve regeneration in a transection and anastomosis model as determined 6 weeks after surgery., Clinical Relevance: These findings support the assumption that mechanical, versus trophic, effects predominate when nerve ends are closely apposed.

A 3.5-mm cortical orthopedic screw was compared with a 4.0-mm cancellous screw for maximal load to failure in the pelvis of immature dogs. The pelvis from young cadavers (7 to 13 months old) was divided into hemipelves and used for testing of the 2 screw types. Two sites in each hemipelvis were used, mid-shaft of the ilium and mid-sacrum, including the wing of the ilium. The screws were extracted, and maximal load to failure and mode of failure were recorded. Maximal load to failure per millimeter of engaged thread was calculated. In either pelvic site, the 4.0-mm cancellous screw required a significantly (P < 0.05) higher pullout force per millimeter of engaged screw threads than did the 3.5-mm cortical bone screw.

Evoked potentials were induced by transcranial stimulation and recovered from the spinal cord, and the radial and sciatic nerves in six dogs. Stimulation was accomplished with an anode placed on the skin over the area of the motor cortex. Evoked potentials were recovered from the thoracic and lumbar spinal cord by electrodes placed transcutaneously in the ligamentum flavum. Evoked potentials were recovered from the radial and sciatic nerves by surgical exposure and electrodes placed in the perineurium. Signals from 100 repetitive stimuli were averaged and analyzed. Waveforms were analyzed for amplitude and latency. Conduction velocities were estimated from wave latencies and distance traveled. The technique allowed recovery of evoked potentials that had similar characteristics among all dogs. Conduction velocities of potentials recovered from the radial and sciatic nerves suggested stimulation of motor pathways; however, the exact origin and pathway of these waves is unknown.

Eight adult male Beagles were given 1 microgram of 1-deamino-8-D-arginine vasopressin (DDAVP)/kg of body weight, SC or by slow IV infusion on separate occasions. Both routes of administration induced highly significant increases (P less than 0.0001) in plasma concentrations of von Willebrand factor (vWf) antigen (Ag) and botrocetin cofactor (BCf) activity, an indication of platelet-associated vWf activity. In most instances, increases in plasma vWf:Ag and BCf values induced by SC injection were as large as or larger than those induced by slow IV infusion. With both routes of administration, BCf activity increased more than the vWf:Ag concentration, so that high BCf-to-vWf:Ag ratios were found in plasma after DDAVP administration. In plasma samples obtained before DDAVP administration, sodium dodecyl sulfate-electrophoresis resolved the vWf into a series of multimeric proteins with molecular weights similar to those of human vWf. Sodium dodecyl sulfate-electrophoresis of plasma samples obtained after DDAVP administration revealed mainly the larger molecules of vWf that were increased by DDAVP administration.

The buccal mucosa bleeding time (BMBT; duration of hemorrhage from standardized cuts made with a spring-loaded disposable device in the mucosal surface of the upper lip) was used to evaluate the hemostatic competence of dogs. The mean (+/- SD) BMBT for 34 healthy dogs was 2.62 +/- 0.49 minutes. The BMBT of healthy dogs anesthetized with halothane or tranquilized with xylazine were not significantly different from the BMBT of healthy dogs evaluated without chemical restraint. The BMBT was significantly (P less than 0.01) prolonged 21 hours after aspirin (10 mg/kg of body weight) was administered orally to 10 healthy dogs; however, the mean aspirin-induced increase in BMBT was only 0.40 minutes. The BMBT of 28 of 30 dogs with various diseases not traditionally associated with hemostatic deficiencies were near or within the range of BMBT for healthy dogs; however, 2 dogs had BMBT of greater than 8 minutes. In contrast, BMBT were prolonged in most dogs with diseases known to induce deficient primary hemostasis; the 3 dogs with thrombocytopenia (less than or equal to 20,000 platelets/microliter), the 7 Doberman Pinschers with von Willebrand's disease (von Willebrand factor antigen; less than or equal to 18 U/dl), and 5 of the 6 dogs with severe azotemia (serum urea nitrogen; greater than or equal to 124 mg/dl) had prolonged BMBT. The BMBT of 16 dogs were determined immediately before they were subjected to various surgical procedures, and the severity of the hemorrhage encountered during these procedures was subjectively evaluated; the amount of hemorrhage from 12 of the 16 dogs was considered to be appropriate for the corresponding surgical procedures, but the remaining 4 dogs bled excessively during surgery.(ABSTRACT TRUNCATED AT 250 WORDS)