Nerve root signature caused by intervertebral disc disease in 83 dogs

Abstract

The nerve root signature (NRS) is a form of lameness usually caused by neurologic lesions, such as attenuation or inflammation of the nerve root/spinal nerve. However, it can be confused with a sign of orthopedic diseases, as NRS can be caused by both orthopedic and neurologic pathologies. Etiologies involve degenerative diseases such as arthropathies, intervertebral disc disease (IVDD), or neoplasia and inflammation. The purpose of this study is to analyze and present the features of NRS caused by IVDD in 83 dogs. A retrospective case collection was performed. Cases with neurologic NRS and Magnetic Resonance Imagingdiagnosed IVDD were collected. Dogs with suspected or confirmed orthopedic diseases were excluded. In total, 162 cases were found; of those, 83 met the inclusion criteria. The most commonly affected spinal cord segment was cervicothoracic (C6-T2) (45/83) with a tendency to involve C6-C7 intervertebral disc space (24/83). The onset of the symptoms was acute in 53/83. Protrusions (43/83) were slightly more frequent than extrusions (39/83). Surgical treatment was chosen in 26/83 cases. Of those treated surgically, a ventral slot (16/26) or hemilaminectomy (8/26) was performed. Clinical signs resolved within 72 hours in only 4/71 (5.6%) of dogs, within 3-7 days in 19/71 (26.8%), within 1-4 weeks in 28/71 (39.4%) and in 20/71 (28.2%) of dogs, clinical sign resolution was not reached within months or remained stable. We present a common syndrome that is difficult to manage and often results in unsatisfying outcomes. If our findings are confirmed by future studies, therapeutic protocols should be reevaluated.