Neurology and Neurosurgery
Allen Sisson, DVM, MS, DACVIM
Dr. Allen Sisson
Two-year-old, neutered, 210-pound English Mastiff named Jack
HISTORY AND PRESENTING COMPLAINT
For one year, Jack’s left fore and left pelvic limb occasionally knuckled or slipped to the side when walking. Forty-eight hours before presentation, he began to limp on his left forelimb. Twelve hours before presentation, he limped severely on the left forelimb and both pelvic limbs were unsteady. Jack was presented to the referring veterinarian a few hours later and frequently collapsed on all four legs; he could barely walk. By the time he arrived at the Angell Animal Medical Center later the same day, he was unable to stand or walk and was brought in on a stretcher.
PHYSICAL AND NEUROLOGICAL EXAMINATION
Jack’s physical examination was normal. On neurological examination he was alert, responsive and friendly. Jack was able to maneuver into a sternal position unassisted and he could attempt to stand; however, he could not stand with all four legs. When his weight was fully supported by the examiners, he had purposeful gaiting movements in all four legs; however, he could not bear any weight on his limbs and the left thoracic limb was in a constant, fully knuckled posture. His cranial nerves were all normal. He had no conscious proprioception and no hopping ability in all four limbs. Jack’s thoracic limb reflexes were absent and his pelvic limb reflexes were hyper-reflexic. His cervical spine was not painful on manipulation. These findings indicated a C1-T2 worse on the left spinal cord lesion, most likely C6-T2, due to the thoracic limb hyporeflexia. Differential diagnosis included cervical vertebral instability static or dyncamic stenosis (Wobblers Syndrome), cervical intervertebral disc herniation, neoplasia, spinal cord hemorrhage or myelitis (immune mediated or infectious).
Hemogram, serum general chemistry profile and urinalysis results were normal. Jack was anesthetized and an MRI of the cervical spine was performed. Articular facet degenerative osteoarthritis was identified at all cervical disc spaces. Significant cord compression was identified at C3-4, C4-5, C5-6 and C6-7. Articular facet lateral impingement was the greatest factor at C3-4 and C4-5; however, a large cystic lesion was identified on the right extending from C5-6 to C6-7, displacing the cord to the left side. This cystic structure was believed to be a synovial cystic lesion, associated with the articular facets. Articular facet degenerative change also contributed to narrowing of the canal at the C5-6 and C6-7 sites. There was no significant cord compression at C7-T1. However, mild degenerative change was present, associated with the articular facets at this site as well. Static stenosis cervical vertebral instability, secondary to articular facet osteoarthritis spinal cord compression (Wobblers syndrome) from C3 to C7, was diagnosed.
A ventral cervical approach was made from C3 to C7. Interbody bone cement plugs using methyl methacrylate were placed at all four intervertebral disc spaces where the spinal cord was compressed, while those sites were held in traction. As additional stabilization at the caudal three sites, two parallel, monocortical, bone screw locking plates were placed on either side of the ventral midline of vertebral bodies C4 to C7. A cancellous bone graft harvested from the right proximal humarus was placed ventral to the locking bone plates at all operated cervical sites.
|Jack at home, 8 months post-operatively|
Jack recovered extremely well from surgery, with steady improvement in his ability to ambulate each day after surgery. Within 72 hours he was able to walk, using his front limbs normally. One week post-operatively, he could walk using all four legs without assistance. Ten days post-operatively, he had recovered enough strength to go home, walking unassisted but with significant pelvic limb ataxia. Jack returned to the Angell Animal Medical Center for a follow-up examination and cervical radiographs seven weeks post-operatively. On examination he was able to stand and walk unassisted with a normal thoracic limb gait and only very mild pelvic limb ataxia, occasionally scuffing the left pelvic limb nails and crossing over the pelvic limbs slightly on turns. Cervical radiographs taken at that time found all the implants remained well in place. The owners reported that by two-and-a-half months post-surgery, Jack’s gait was normal and he was very active, running and going up and down stairs without restrictions. It has now been nine months since surgery and he continues to do well.
FOR MORE INFORMATION
Angell Animal Medical Center’s Neurology/Neurosurgery service is open from 8:00 a.m. to 5:00 p.m., Monday through Saturday. Patients are seen by appointment and through referral by their primary veterinarian. Appointments and referrals are made by calling the Neurology secretary at 617-541-5140.