[Value of preoperative investigations in the so-called "cervical myelopathy" (author's transl)].

The particular value of clinical, radiological and electromyographical features is compared in 42 patients with motor deficit related to cervicarthrosic myelopathy or amyotrophic lateral sclerosis. The initial onset of the disease was identical (motor deficit and long tracts pathways involvement). Three different groups were identifyed according to the evolution: -- Group I: (13 cases): true lateral amyotrophic sclerosis which were not operated on. -- Group II (10 cases): myelopathy called "cervicarthrosic" because of radiological findings which were operated on but had the same steady worsened course as a lateral amyotrophic sclerosis. -- Group III (19 cases): cervical myelopathy which had surgery. The operation brought about stabilization or fairly good recovery over the 18 months following at least. From a clinical aspect, the "Lhermitte sign" or objective sensitive deficit are strongly significant for cervical myelopathy. On the contrary, diffuse fasciculations specially in the tongue seem to be mostly found in lateral amyotrophic sclerosis, whereas they are restricted into the paralysed area in cervical myelopathy. Electromyographic examination is decisive: simple activity with high frequency motor units (increased amplitude and polyphasic waves) or "preponderant potentials" into a cranial nerve territory or three segments of the lower limbs are frequently found in lateral amyotrophic sclerosis. These electromyographic features are less significant in the upper limbs. The neuroradiological findings lonely cannot assert definitely the cervicarthrosic origin of the myelopathy but visualize the conflicting situation between the spinal cord and the cervical canal and allow to choose the surgical procedure.