Hirayama Disease: A Diagnostic and Therapeutic Challenge

Abstract

Figure 2: (A) Sagittal T2-weighted magnetic resonance imaging (MRI) in neutral position with minor T2-weighted signal change at C6-C7. (B) Sagittal T2-weighted flexion MRI with anterior displacement of the posterior thecal sac and cord compression, as well as epidural venous distension confirming the diagnosis of Hirayama disease. (C) Postoperative C6-C7 anterior cervical discectomy and fusion neutral lateral view.

Management of dynamic cervical kyphosis with dorsal epidural lipomatosis: a Hirayama disease variant? Illustrative case

“…In classic Hirayama disease, a loss of normal cervical lordosis, focal kyphosis, and dorsal epidural fat results in anterior compression of the spinal cord in flexion, 18 resulting in episodic ischemic events that chronically damage cells in the anterior horn. 19 , 20 Over time, this may force the cervical spinal cord into a more anterior position within the spinal canal, causing increased tethering to the ventral vertebral bodies and an increase in dorsal epidural space. 14 This imposes increased mechanical stress on the cervical cord, which propagates further ischemic injury to the anterior region, resulting in progressive lower motor neuron type weakness.…”

“…Although an anterior approach is generally preferable given technical advantages, both anterior and posterior cervical fusions are commonly performed to decompress the spinal cord and fixate the column to limit cervical flexion. 20,[24][25][26][27][28] In the literature, these interventions have been demonstrated to halt disease progression and even alleviate prior symptoms in some patients with Hirayama disease. For example, in 1 study of a 31-year-old man with a 10-year history of Hirayama disease refractory to other treatment modalities, 3-level ACDF was shown to immediately improve motor-evoked potential amplitude and myelopathy, as well as reverse muscle wasting at 1 year after surgery.…”

“…30 Numerous additional studies have reported similarly promising findings, with both reversal of prior symptoms and halted disease progression reported following cervical fusion either by an anterior or posterior approach. 20,24,26,28,31 Despite the promising reports in the literature mentioned above, surgical management of Hirayama disease remains controversial. Given that the disease's progression spontaneously arrests within 5 years for the majority of patients, with this timeframe being shortened with the use of a cervical collar, many surgeons advocate for a more conservative approach.…”

Hirayama Disease in an Adolescent Male With Right Hand Weakness and Muscle Wasting

“…Hirayama disease, also known as monomelic amyotrophy 1 or juvenile muscular atrophy of the upper extremity, 2,3 is a rare neurologic condition that involves the inferior motor neurons 1 and commonly affects the C7 to T1 spinal nerves and their myotomes. 4 Hirayama first described this type of cervical myelopathy in 1959, stating that it was clinically differentiated from the other known types of motor neuron disease. 5 Characterized by insidious onset, 1,6,7 this disease, commonly associated with Asian descent, has a male predominance ranging from 7:1 4,6 to 20:1, 7,8 depending on the population, and is typically diagnosed during the second and third decades of life.…”

“…4 Hirayama first described this type of cervical myelopathy in 1959, stating that it was clinically differentiated from the other known types of motor neuron disease. 5 Characterized by insidious onset, 1,6,7 this disease, commonly associated with Asian descent, has a male predominance ranging from 7:1 4,6 to 20:1, 7,8 depending on the population, and is typically diagnosed during the second and third decades of life. 1,6,8,9 Although the exact pathophysiology is unknown, one theory is an imbalance between the growth of the vertebral column and that of the spinal canal contents, 7 a discrepancy that results in forward displacement of the posterior dural sac with neck flexion, 10 leading to compression and injury of the spinal cord with posterior damage to the anterior horn cells.…”