Severe cervical flexion myelopathy with long tract signs: a case report and a review of literature

Abstract

Introduction: Hirayama disease, a type of cervical flexion myelopathy, is a rare neurological disease characterized by muscular atrophy of the forearms and hands. Generally, the pathology is limited to the gray matter of the anterior horns in the lower cervical spinal cord. However, in rare cases the damage can spread to the white matter and present as long tract signs.

Case presentation: We report on a 30-year-old female whose onset presented as unilateral muscle atrophy of the right hand in her teens. Despite conservative treatment using a cervical collar, she developed prolonged bilateral muscle atrophy, sensory disturbance and spastic gait, along with bladder and rectal disturbances. Her hands were frozen into a 'claw-like' gesture and her intrinsic muscles were highly atrophic. She was unable to unclench her hands. Although the space available for the spinal cord was large, the spinal cord was highly atrophic. She had local kyphosis with a large (61°) flexion range of motion. During flexion the spinal cord was stretched, resulting in contact with the posterior wall of the vertebrae. Posterior fusion surgery was performed to prevent progression of the myelopathy. After surgery, she gained mild improvement in both muscle strength and her hand's movement. However, her spastic gait and muscle atrophy remained.

Discussion: Most cases of cervical flexion myelopathy as represented by Hirayama disease have a self-limiting benign prognosis. However, some cases can develop advanced myelopathy with long tract signs. Long-term follow-up is recommended for these cases because they may require early surgical treatment.

Keywords: Spinal cord diseases; Spine structure.

Figure 1

Photograph showing both left and right hands of the patient illustrating how the severe atrophy of her right side intrinsic muscles results in a ‘claw-like’ appearance due to an inability of the patient to fully unclench her right hand.

Figure 2

Radiography taken without contrast showing (a) that C2/C7 (white lines) was 2° of kyphosis and C4/C7 (black lines) was 31° of local kyphosis. Furthermore, (b) C2/C7 was 63° of kyphosis in flexion and (c) 34° of lordosis in extension.

Figure 3

A magnetic resonance image (MRI) revealing atrophy of the spinal cord resulting in a ‘snake-eye’ appearance. (a) Sagittal MRI showing the area of lesion. (b) Axial MRI showing ‘snake-eye’ appearance (open arrow). (c) MRI taken during flexion, showing a stretched spinal cord, resulting in contact with the posterior wall of the vertebrae (open arrow).

Figure 4

A computer topography (CT) myelogram in flexion showing a space between the spinal cord and the dorsal dura membrane.

Figure 5

Radiography taken post-operatively showing the successful C4–C7 posterior fusion.