Accuracy of the withdrawal reflex for localization of the site of cervical disk herniation in dogs: 35 cases (2004-2007).

OBJECTIVE: To evaluate the accuracy of neurologic examination versus magnetic resonance imaging (MRI) in localization of cervical disk herniation and evaluate the usefulness of withdrawal reflex testing in dogs. DESIGN: Retrospective case series. ANIMALS: 35 client-owned dogs with a single-level cervical disk herniation as determined via MRI. PROCEDURES: 1 of 2 board-certified neurologists performed a complete neurologic examination in each dog. Clinical signs of a cervical lesion included evidence of neck pain and tetraparesis. The withdrawal reflex was used for neuroanatomic localization (C1-C5 or C6-T2). Agreement between results of neurologic and MRI examinations was determined. RESULTS: Agreement between neurologic and MRI diagnoses was 65.8%. In 11 dogs in which the lesion was clinically localized to the C6-T2 segment on the basis of a decreased withdrawal reflex in the forelimbs, MRI revealed an isolated C1-C5 disk lesion. In 1 dog, in which the lesion was suspected to be at the C1-C5 level, MRI revealed a C6-T2 lesion. Cranial cervical lesions were significantly associated with an incorrect neurologic diagnosis regarding site of the lesion. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the withdrawal reflex in dogs with cervical disk herniation is not reliable for determining the affected site and that a decreased withdrawal reflex does not always indicate a lesion from C6 to T2.

Detection and distribution of apoptotic cell death in normal and diseased canine cranial cruciate ligaments.

One of the possible initiating factors in canine cranial cruciate ligament (CCL) rupture could be an abnormal pattern of ligament cell death. This study compared apoptotic cell death in sections of ruptured CCLs and normal controls, and examined nitric oxide (NO) production in joint tissues and correlated this to apoptosis. CCLs and cartilage from the lateral femoral condyle were harvested from 10 healthy dogs and 15 dogs with CCL rupture and ligaments were further processed to detect cleaved caspase-3 and to determine supernatant NO production in explant cultures. Apoptotic activity was greater in ruptured ligaments compared to controls. NO in ligaments showed a moderate but significant positive correlation with caspase-positive cells. The results suggest that increased apoptosis has a role in CCL rupture and that apoptosis may be influenced by local NO production.