To assess associations of severity of neurologic signs (neurologic score), involvement of an intumescence, and findings of magnetic resonance imaging (MRI) with interval to recovery and outcome in dogs with presumptive acute noncompressive nucleus pulposus extrusions. Retrospective case series. 42 dogs with presumptive acute noncompressive nucleus pulposus extrusions. Medical records and magnetic resonance (MR) images of dogs evaluated from 2000 through 2007 were reviewed. Inclusion criteria were acute onset of nonprogressive myelopathy following trauma or strenuous exercise, MRI of the spine performed within 7 days after onset, MRI findings consistent with acute noncompressive nucleus pulposus extrusions, and complete medical records and follow-up. Clinical neuroanatomic localization of lesions was to the C1-C5 (n = 6), C6-T2 (6), T3-L3 (28), and L4-S3 (2) spinal cord segments. Median neurologic score was 3.5. Median duration of follow-up was 804 days (range, 3 to 2,134 days) after onset of neurologic signs. Outcome was successful in 28 (67%) dogs and unsuccessful in 14 (33%) dogs. Severity of neurologic signs, extent of the intramedullary hyperintensity on sagittal and transverse T2-weighted MR images, and detection of intramedullary hypointensity on GRE images were all associated with outcome on univariate analysis. Results of multivariate analysis suggested that maximal cross-sectional area of the intramedullary hyperintensity on transverse T2-weighted MR images was the best predictor of outcome. Clinical and MRI findings can help predict outcome in dogs with acute noncompressive nucleus pulposus extrusions.
