K. Shinomiya et al., NEURORADIOLOGIC AND ELECTROPHYSIOLOGIC ASSESSMENT OF CERVICAL SPONDYLOTIC AMYOTROPHY, Spine (Philadelphia, Pa. 1976), 19(1), 1994, pp. 21-25
Dissociated motor loss due to cervical spondylosis and disc herniation
was evaluated in 10 patients who presented with left deltoid paresis
in the absence of sensory deficits or myelopathy. All of these cases u
nderwent cervical anterior decompression. Based on magnetic resonance
imaging, computed tomography myelography, and computed tomography disc
ography, patients were divided into two pathologic types: The first sh
owed focal bony spur and disc herniation with axial cord rotation and
nerve root compression, and the second demonstrated ventral cord flatt
ening. Electrophysiologic studies included evoked muscle action potent
ials. Motor evoked potentials, recorded epidurally from the ventral as
pect of the thecal sac and the nerve root within the anterior discecto
my or vertebrectomy sites, proved clinically most useful. Combining th
e latest available neuroradiologic and electrophysiologic information,
4 types of neural injury associated with deltoid pareses were identif
ied in the 10 patients. The first included isolated C5 nerve root lesi
ons; the second, C6 nerve root lesions; the third, both C5 and C6 nerv
e root lesions, and finally, intrinsic cord pathology.