Hirayama Disease: Latest Insights into an Intriguing Disorder

Area of Science:

• Neurology
• Orthopedic Surgery
• Radiology

Background:

• Hirayama disease (HD) is a rare cervical myelopathy causing progressive, asymmetrical upper limb weakness.
• It typically affects adolescent males and leads to irreversible functional deficits over 3-5 years.
• Rarer phenotypes include distal bimelic amyotrophy and motor neuron variants.

Purpose of the Study:

• To review the latest insights into Hirayama disease pathophysiology.
• To discuss diagnostic imaging, including dynamic flexion MRI, and its findings.
• To explore management strategies, including conservative and surgical options for preventing limb weakness.

Main Methods:

• Review of current literature on Hirayama disease.
• Analysis of diagnostic criteria and imaging characteristics, particularly dynamic flexion MRI.
• Evaluation of surgical techniques and outcomes for managing progressive cases.

Main Results:

• Dynamic flexion MRI shows high sensitivity (93%) and specificity (98%) for HD diagnosis.
• Distinctive MRI findings include epidural flow voids and anterior dural sac displacement.
• Anterior cervical discectomy and fusion with plating is considered an ideal surgical approach.

Conclusions:

• Early diagnosis of Hirayama disease is crucial for effective management.
• Dynamic flexion MRI is a key diagnostic tool for identifying characteristic spinal cord changes.
• Surgical intervention, such as anterior cervical discectomy and fusion, may prevent severe residual limb weakness.