MODERN MATERIALS FOR IMPLANTS USED IN THE TREATMENT OF DOGS WITH WOBBLER SYNDROME

Wobbler's syndrome or caudal cervical spondylomyelopathy is a disease of the cervical spine in dogs of large and giant breeds, characterized by dynamic or static compression of the cervical spinal cord and nerve roots, which leads to neurological deficits and neck pain. Currently, there are many materials for the manufacture of various implants, as well as prosthetic discs, which are successfully used in the treatment of dogs with Wobbler syndrome, but veterinary neurologists have certain dissatisfaction with the results of surgical treatment, as a result of which a number of postoperative complications are noted. This makes it necessary to use new materials for the manufacture of implants. Currently, the vast majority of veterinary specialists use only titanium and stainless steel alloys (304V and 316LVM) as a material for cages, screws and plates. However, a number of shortcomings of these materials indicate the need for a search new innovative materials with improved characteristics. Currently, the materials used for the manufacture of implants in human medicine are of great interest, but have not yet found application in veterinary medicine (with the exception of stainless steel and titanium alloys). Among such materials are polyether etherketone (PEEK), carbon fiber reinforced polyether etherketone (CFR-PEEK), cobalt-chromium alloys, nitinol, tantalum. The article reflects the characteristics of these materials for the manufacture of implants, their advantages and disadvantages.

Isolation of an Equine Foamy Virus and Sero-Epidemiology of the Viral Infection in Horses in Japan

An equine foamy virus (EFV) was isolated for the first time in Japan from peripheral blood mononuclear cells of a broodmare that showed wobbler syndrome after surgery for intestinal volvulus and the isolate was designated as EFVeca_LM. Complete nucleotide sequences of EFVeca_LM were determined. Nucleotide sequence analysis of the long terminal repeat (LTR) region, gag, pol, env, tas, and bel2 genes revealed that EFVeca_LM and the EFV reference strain had 97.2% to 99.1% identities. For a sero-epidemiological survey, indirect immunofluorescent antibody tests were carried out using EFVeca_LM-infected cells as an antigen against 166 sera of horses in five farms collected in 2001 to 2002 and 293 sera of horses in eight farms collected in 2014 to 2016 in Hokkaido, Japan. All of the farms had EFV antibody-positive horses, and average positive rates were 24.6% in sera obtained in 2001 to 2002 and 25.6% in sera obtained in 2014 to 2016 from broodmare farms. The positive rate in a stallion farm (Farm A) in 2002 was 10.7%, and the positive rates in two stallion farms, Farms A and B, in 2015 were 40.9% and 13.3%, respectively. The results suggested that EFV infection is maintained widely in horses in Japan.

A literature review of finite element models for the study of cervical spondylomyelopathy

Cervical spondylomyelopathy (CSM), or wobbler syndrome, affects mainly the cervical region of the vertebral column of large- and giant-breed dogs, causing compression of the spinal cord and/or nerve roots. Dynamic components are considered to play a role in the condition, but its pathophysiology has not been fully explained. Finite element analysis consists in creating a computer model capable of simulating the biomechanics of the structures of interest. The present work aims to clarify aspects related with construction of finite element models and CSM through a review of literature on both topics, stressing the benefits of using finite element models to study the pathophysiology and treatment of CSM. Despite existing difficulties in generating a finite element model that represents the cervical spine of the dog, development of such a model and further biomechanical studies should contribute for a greater understanding of CSM.

Myelographic diagnosis and results of surgical treatment of caudal cervical spondylomyelopathy in dogs: a retrospective study (2000–2010)

The outcomes of six different surgical techniques of caudal cervical spondylomyelopathy treatment in dogs with static and dynamic spinal cord compressions were assessed. Out of 425 dogs with cervical spine diseases, caudal cervical spondylomyelopathy was diagnosed in 69 dogs. Dynamic myelographic study was performed in 48 of them as a diagnostic method necessary for choosing the appropriate technique of surgical treatment. Twenty-five out of the 48 dogs underwent surgery. The best results of the surgical treatment of static compression were achieved with a ventral slot (89% of the nine surgical interventions) with partial improvement 48 h after surgery and marked improvement 8 weeks after surgery. For dynamic compressions, vertebral traction and stabilization with intervertebral washer plus vertebral body screws and polymethylmethacrylate bridge was found to be the most successful surgical treatment with significant improvement in 62% of the thirteen surgical interventions 8 weeks after surgery. In 5 dogs (20%), two intervertebral spaces with caudal cervical spondylomyelopathy were surgically treated. Recurrence was observed in 6 dogs (24%) after the mean period of 20 months (5 to 44 months) after surgery. Direct ventral slot decompression could be recommended for clinical cases of the caudal cervical spondylomyelopathy with static compression, and intervertebral washer plus vertebral body screws and polymethylmethacrylate bridge for dogs with dynamic compression, respectively. Our findings refer to the results of surgical treatment in a relatively large number of dogs with caudal cervical spondylomyelopathy and can help surgeons to choose an effective surgical method of treatment in dogs with wobbler syndrome based on dynamic myelographic study findings.

Ventral stabilization and facetectomy in a Great Dane with wobbler syndrome due to cervical spinal canal stenosis

SummaryThis report describes the management of clinically significant, single level cervical spinal canal stenosis associated with articular facet hypertrophy in a three-year-old Great Dane dog, by combined surgical decompression and spinal stabilization. Spinal column stabilization was achieved by ventral application of two String of Pearls locking plates and subsequent decompression was accomplished by unilateral facetectomy. The six-month postoperative reassessment examination confirmed satisfactory clinical outcome with a complete return to normal activity, resolution of neurological deficits and maintenance of implant positioning.