Somatosensory and motor evoked potentials in dogs with chronic severe thoracolumbar spinal cord injury

H.Z Hu,N.D Jeffery,N Granger

doi:10.1016/j.tvjl.2018.05.007

Abstract

Some dogs that become paraplegic after severe spinal cord injury regain ambulation on the pelvic limbs despite permanent loss of pelvic limb sensation, a phenomenon termed ‘spinal walking’. Plastic changes in spinal cord circuitry are thought to mediate this form of recovery but the precise circumstances that favor its development are not known. More information on this phenomenon would be helpful because it might be possible to coax more function in chronically paraplegic animals so improving their, and their owners’, quality of life. We analysed the correlation of ‘spinal walking’ and pelvic limb pain sensation with recordings of scalp and spinal somatosensory and transcranial magnetic motor evoked potentials. We prospectively examined 94 paraplegic dogs (including 53 Dachshunds) that had sustained T10 to L3 spinal cord injury (including 78 dogs with acute intervertebral disc herniation) at a median time of 12.0 months from injury.Nine dogs exhibited ‘spinal walking’ and nine other individuals had intact pelvic limb pain sensation. Of 34 tested, 12 dogs had recordable scalp somatosensory evoked potentials. Fifty-three of 59 tested dogs had recordable spinal somatosensory evoked potentials, but only six had recordable potentials cranial to the lesion. Twenty-two of 94 tested dogs had recordable transcranial magnetic motor evoked potentials in the pelvic limb(s). There was no apparent association between intact evoked potential recording and either spinal walking or intact pain sensation. We conclude that factors other than influence, or lack of influence, of input carried by spinal cord long tracts mediate recovery of spinal walking.

Highlights

Spinal cord injury is common in pet dogs, mainly resulting from intervertebral disc herniation, fractures and vascular lesions (Moore et al, 2017)
Participants were pet dogs that had been prospectively enrolled with owner consent into one of two clinical trials of novel therapy for chronic severe spinal cord injury
C Scalp SEP recording was performed on 34 dogs of which 12 (35.3%) had recordable S potentials (Table 2); none of these 34 dogs displayed spinal walking

Summary

Introduction

Spinal cord injury is common in pet dogs, mainly resulting from intervertebral disc herniation, fractures and vascular lesions (Moore et al, 2017). Because it is rarely possible to T ascertain whether the spinal cord is truly transected in clinical injuries, spinal walking in P these individuals is defined by the loss of ‘deep pain perception’ in association with the E ability to walk for a potentially unlimited period and the ability to regain a standing posture ACC from recumbency (Gallucci et al, 2017). At present it is uncertain what factors are important in promoting development of spinal walking. (3), we thought that dogs with evidence P of longer regions of spinal cord loss would be more likely to exhibit spinal walking (because, E as a corollary of hypothesis 1, they would less likely have interference of descending ACC influence on pattern generators controlling pelvic limb movements)

Materials and methods

Results

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