Cervical spondylomyelopathy (CSM) is one of the most common diseases of the cervical spine of large and giant breed dogs. Currently, the most accepted means of evaluating the response to treatment in a patient with CSM is a subjective measure based on the owner and clinicians’ perception of the patient’s gait. This form of evaluation is highly subjective and can suffer from observer bias. The goals of this study were (1) to identify differences in force plate parameters between Doberman Pinschers with and without CSM that could be used as objective outcome measures and (2) to utilize digital video motion capture to compare multiple kinematic parameters between Doberman Pinscher dogs with and without CSM.
Nineteen Doberman pinschers were prospectively studied; 10 clinically normal dogs and 9 with CSM. Neurologic examinations were performed in all dogs. CSM-affected dogs had their diagnosis confirmed with a 3.0 T MRI. Force plate analysis was performed in all 4 limbs of all dogs. At least 4 runs of ipsilateral limbs were collected from each dog. Eight force platform parameters were evaluated. In addition, the coefficient of variation (CV) within each limb was also calculated for each parameter. A repeated measures approach was used to analyze the data. Peak mediolateral force (PMLF), peak vertical force (PVF), and peak propulsive force (PPF) were significantly smaller in CSM-affected dogs when compared to normal dogs. Analysis using the CV, revealed significantly more variability of PVF from all four limbs in CSM-affected dogs compared to normal dogs with the largest difference in variability of PVF seen in the thoracic limbs of affected dogs.
For digital motion capture, the same nineteen Doberman Pinchers were studied; 10 clinically normal dogs and 9 with CSM. All dogs were fitted with a Lycra® bodysuit and 32 reflective markers were applied. 3-D motion capture was performed and used to reconstruct a 3-D stick diagram representation of each dog from which several parameters of interest were measured. Parameters evaluated included stride (duration, length, height), maximal and minimal spinal angles, elbow and stifle flexion and extension, and maximum and minimum distances between the thoracic and pelvic limbs. Using a random effects linear regression model, all parameters were compared between groups. CSM-affected dogs had smaller minimum thoracic limb distance and maximum thoracic limb distance. Additionally, stride duration in the thoracic limbs was also significantly smaller in CSM-affected dogs when compared to normal dogs. In the pelvic limbs, the average stifle flexion and extension were different between groups.
These results reveal that while the variability of PVF in all four limbs and in particular the thoracic limbs, seems to distinguish clinically normal Dobermans from those moderately to markedly affected with CSM, force plate analysis seems less reliable to distinguish mildly CSM-affected from normal Dobermans. Findings from the kinematic study suggest that computerized gait analysis reveals more consistent kinematic differences in the thoracic limbs compared with the pelvic limbs of CSM-affected Doberman Pinscher dogs.