Historical Evolution, Experience and Expected Outcomes of Cervical Vertebral Stenotic Myelopathy Surgery

Historical evolution:
Surgical technique:
The concept of surgical treatment of cervical vertebral stenotic myelopathy (CVSM) was first published by Wagner et al at Washington State University in 1979. Using Cloward’s approace to the ventral neck, a 16mm hole was drilled in the intervertebral space and a frozen 18mm dowel of homologous bone inserted. Partial or complete fusion was achieved in 11/12 horses. In a further case, series increasing the hole and dowel size to 25mm showed significantly improved fusion at 3 months postoperatively. In the early 1980s, the same group showed better post-operative bony fusion of the intervertebral space and reduction in mobility of the joint when a 25mm stainless steel basket packed with cancellous, autogenous bone from the drillings was used. The basket was invented by a human surgeon, George Bagby, who had considerable influence on the development of the procedure in horses. Although the Bagby Basket (BB) was inserted with the neck in extension so that the compressive forces would hold it in place post-operatively, it still had a tendency to migrate ventrally and many surgeons applied a plastic “lubra plate” fixed with cancellous AO screws on the ventral surface to discourage this.

Although there was a relatively low incidence of serious complications such as implant migration or fracture at the implant site, these complications were often catastrophic; consequently, techniques using Kerf Cut Cylinders (KCC) were trialed on 75 horses by Grant et al. In group 1 (control group) a BB was used, in group 2 a self-tapping KCC and in group 3 a KCC was inserted into a pre-tapped hole without tamping. Implant migration was significantly less in group 3 and this protocol is now the received technique for ventral stabilization of CVSM lesions with the KCC.  [...]