Vertebral distraction‐fusion for cervical spondylopathy using a screw and double washer technique

Abstract

A technique using two interbody washers and a transvertebral screw was utilised to distract the cervical vertebrae and so decompress the spinal cord in 17 dobermann pinschers and three great danes with cervical spondylopathy. Neurological dysfunction was graded (1 to 5) according to the degree of hindlimb ataxia. Myelography showed evidence of spinal cord compression at C6‐7 in all dogs and at C5‐6 in six dogs. Twenty‐three compressive lesions were reduced when traction was applied to the cervical spine. Seventeen dogs improved following surgery and of these 10 improved by two or more grades. Follow‐up radiographic studies indicated resorption of end‐plate bone and eventual fusion of the vertebral bodies. Displacement of the screw into the vertebral canal, remodelling of the vertebral canal, fracture of C6 ventral spinous process and breakage of the screw were implant associated complications. The distraction‐fusion technique with modifications appears to be an effective procedure for the management of cervical spondylopathy in dogs in which the compressive lesion is soft tissue in nature.

Cervical spondylomyelopathy

“…Stabilization may even benefit dorsally located soft tissue or osseous lesions by limiting movement locally. Fusion has been shown to cause the regression of ligamentum flavum lesions in dogs and of bony articular lesions in horses (Grant et al, 1985;Seim, 1986;McKee et al, 1990). Therefore cement plugs should be considered for dogs with certain types of traction non-responsive lesions such as those caused by osseous compression of the dorsal vertebral canal (11.15).…”

“…B: This dog did well until it fell down the stairs 6 weeks after distraction at C6/7. Failure of a screw in C7 did not cause clinical signs (McKee et al, 1990). The dog had also shown a change in bark since surgery.…”

“…Spinal cord compression can also be caused by a relative change in the position of an implant secondary to bony remodeling and collapse of a distracted interspace (McKee et al, 1990). In addition, late-onset discospondylitis has been recorded 6 and 26 months after a surgery and it can also occur as a complication of an unrelated surgical procedure (Ellison et al, 1988;Dixon et al, 1996) (14.11).…”

“…This is presumably because there is often significant loss of neural tissue at the site of the lesion (Read et al, 1983;Sharp et al, 1995). It is therefore likely that the outcome will be better if surgery is done earlier in the disease process (Chambers et al, 1986;VanGundy, 1988;McKee et al, 1990).…”

Doença do disco intervertebral Hansen tipo II em cães: fisiopatologia, abordagem clínico-cirúrgica e controvérsias

“…De acordo com o estudo, a descompressão medular provavelmente foi incompleta, mas a estabilização vertebral pode ter desempenhado um papel importante, pois a estabilidade conferida pela placa vertebral no corpo evitou protrusão adicional dos discos, preveniu a compressão dinâmica da medula espinhal e promoveu atrofia do disco intervertebral a longo prazo. Relata-se atrofia do material discal anular na coluna cervical de cães após distração-estabilização (McKEE et al, 1990). Segundo Mckee e Downes (2008), o papel relativo da descompressão medular e estabilização vertebral são especulativos, e o potencial de atrofia do anel fibroso em longo prazo, secundário a estabilização, não foi determinado.…”