AVMA - Journal of the American Veterinary Medical Association - 232(4):559

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

Franck Forterre, DVM, Martin Konar, DVM, Ales Tomek, DVM, Markus Doherr, DVM, PhD, Judith Howard, DVM, David Spreng, DVM, DACVECC, Marc Vandevelde, DVM, PhD, André Jaggy, DVM, PhD

Department of Clinical Veterinary Medicine, Division of Small Animal Surgery, Vetsuisse Faculty, University of Bern, CH-3012 Bern, Switzerland. (Forterre, Spreng); Department of Clinical Veterinary Medicine, Division of Radiology, Vetsuisse Faculty, University of Bern, CH-3012 Bern, Switzerland. (Konar); Department of Clinical Veterinary Medicine, Division of Animal Neurology, Vetsuisse Faculty, University of Bern, CH-3012 Bern, Switzerland. (Tomek, Vandevelde, Jaggy); Department of Clinical Veterinary Medicine, Division of Clinical Research, Vetsuisse Faculty, University of Bern, CH-3012 Bern, Switzerland. (Doherr); Department of Clinical Veterinary Medicine, Division of Clinical Pathology, Vetsuisse Faculty, University of Bern, CH-3012 Bern, Switzerland. (Howard)

Address correspondence to Dr. Forterre.

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.