[Dorsal sensory level as a false localizing sign in cervical myelopathy]

Cervical myelopathy is a common disorder of the spinal cord. The most frequent symptoms are muscle weakness and spasticity starting in the legs. Occasionally the sensory levels are several spinal cord segments below the cervical lesion which makes diagnosis difficult.

We present the case of a 31 year old man who presented (after exercise) with paresthesia and numbness below the left costal margin in the left hemiabdomen and the left leg. On physical examination there was painful superficial tactile thermic hypoaesthesia at the level of D10 on the left side, together with brisk myotatic reflexes of the legs and indifferent bilateral plantar reflexes. Blood and CSF studies were normal. On cervical MR there was a large hernia of the intervertebral disk at C5-C6 and marked involvement of the spinal cord. Progress after surgery was good. Two months after operation he was symptom free and neurological examination was normal.

Diagnosis of cervical myelopathy may be difficult because of the varied symptoms. There may be a dorsal or lumbar sensory level acting as a false localizing sign. The physiopathological mechanism for this is not clear. Different hypotheses have been put forward based on anatomical distribution of the spino-thalamic tract and on indirect factors (vascular, demyelinization, etc.). In a patient with a dorsal sensory level and normal radiological findings at this level, it is important to study levels above this as well to avoid errors of diagnosis and treatment.