Anatomic description of the basivertebral nerve and meningeal branch of the spinal nerve in the dog.

PURPOSE: The existence of the basivertebral nerve and meningeal branch of the spinal nerve has not been proven in dogs to date. The objectives of this study are to 1) determine whether dogs have a meningeal branch of the spinal nerve (MBSN) and a basivertebral nerve (BVN) and to (2) describe anatomical characteristics of these two nerves. Authors also put forward a discussion on the possible clinical relevance of these findings. MATERIAL AND METHODS: Dissections were performed on six embalmed dogs at the Veterinary Faculty of Barcelona with the use of stereomicroscopy and microsurgery equipment. RESULTS: The MBSN (grossly) and BVN (grossly and histologically) were identified in the cervical, thoracic, and lumbar region in all dog specimens. In addition, other small fibers (suspected nerves) entering the vertebral body through small foramina close to the end plates were identified. Histological examination of the tissues confirmed the presence of nerve fibers (myelinated and unmyelinated) in suspected BVN samples. Results of the present study indicated that dogs have BVNs. Also, suspected nerve fibers were identified among the epidural fat, running from the intervertebral foramina, that likely represent the MBSN. CONCLUSION: These findings open up the discussion on extrapolation of treatment options employed in human medicine for "low back pain", such as BVN ablation, which is discussed in this article. Further anatomic and clinical studies of the innervation for the vertebral body, periosteum, vasculature, dorsal longitudinal ligament and anulus fibrosus are necessary to elucidate possible anatomical variants and breed differences as well as potential clinical (e.g., therapeutic) relevance.

Safety of early postoperative hydrotherapy in dogs undergoing thoracolumbar hemilaminectomy.

OBJECTIVES: Hydrotherapy is a common part of the postoperative care after surgical treatment of thoracolumbar intervertebral disc extrusion in dogs. There are currently no guidelines on when to commence hydrotherapy after surgery. Early hydrotherapy may be associated with an increased risk of postoperative complications including surgical site infection and neurological deterioration. The goal of this study was to report the prevalence and types of postoperative complications in dogs receiving early hydrotherapy. MATERIALS AND METHODS: Eighty-three dogs commencing hydrotherapy within 5 days after surgical treatment for thoracolumbar intervertebral disc extrusion were included in a retrospective descriptive study. All postoperative complications were recorded. RESULTS: Ten minor and 16 major complications were recorded in a total of 26 dogs. The majority of recorded complications were unlikely, but not excluded to be, caused by the initiation time of hydrotherapy. One dog developed a surgical site infection and one dog had a confirmed further extrusion of the originally operated intervertebral disc, which may have been influenced by early initiation of hydrotherapy. CLINICAL SIGNIFICANCE: Early hydrotherapy is possibly associated with occurrence of postoperative complications. Associations between the reported complications and early hydrotherapy, and possible benefits of early hydrotherapy, need to be further investigated before early initiation of hydrotherapy can be recommended.

Hydrated nucleus pulposus herniation in seven dogs.

The clinical signs, magnetic resonance imaging (MRI) findings, treatment and follow-up in seven dogs with hydrated nucleus pulposus extrusion (HNPE) are reported. All dogs had tetraparesis or tetraplegia. T2-weighted MRI revealed extradural hyperintense homogeneous material compressing the cervical spinal cord. After conservative treatment (five dogs) or surgical decompression (two dogs), all dogs returned to ambulatory function within 1 month. Follow-up MRI in conservatively treated dogs revealed complete disappearance of the extruded material. Histopathological examination of surgical specimens confirmed that the retrieved material was extruded nucleus pulposus with evidence of early degeneration.

Intervertebral disc disease in dogs - part 1: a new histological grading scheme for classification of intervertebral disc degeneration in dogs.

Intervertebral disc (IVD) degeneration is common in dogs and can lead to serious disorders. Current treatments can relieve clinical signs of disease, but do not restore IVD function. The development of regenerative strategies for IVD dysfunction requires detailed knowledge of the pathogenesis of IVD degeneration and its underlying mechanisms. Histological examination of IVDs at different stages of degeneration might provide this knowledge, but as there is currently no histological grading scheme for canine IVD degeneration, the aim of this study, which is the first of a two-part series, was to design and validate an appropriate scheme. Three independent observers evaluated 35 IVDs at different stages of degeneration using the scheme. Glycosaminoglycan contents of the nucleus pulposus and macroscopic grading according to Thompson, which are considered 'gold standards' for IVD degeneration, were used to validate the scheme. Reproducibility was assessed by analysing the inter-observer reliability of all individual variables of the grading scheme, using a weighted κ analysis. Significant correlations were found between Thompson grading and total histological score (r=0.94; P<0.01) and between glycosaminoglycan content and total histological score (r=-0.72; P<0.01). Most individual histological variables showed 'moderate' to 'almost perfect' inter-observer reliability. The high correlation with the gold standards in combination with the high reproducibility indicates that the proposed histological grading scheme is reliable and objective for classification of IVD degeneration in both chondrodystrophic and non-chondrodystrophic dog breeds.