Cervical Spine Magnetic Resonance Imaging Findings in Hirayama Disease.

Background Hirayama disease is an uncommon type of cervical cord myelopathy seen typically in young males due to trauma from flexion movements. This study aims to assess the clinical presentations and classify the extent of various cervical spine MRI findings for the local population. Methodology A retrospective study of 13 patients diagnosed with Hirayama disease on cervical MRI was performed from January 2017 to December 2022 at Dr. D. Y. Patil Medical College, Hospital and Research Center, Pune. Results Of the 13 patients, 12 (92%) were male, and one (8%) was female. Nine (69%) patients were in the 16-25-year age group, two (15%) were in the 26-35-year age group, and one (8%) each was in the 6-15-year and 66-75-year age groups. Upper limb weakness was the most common clinical symptom seen in 12 (92%) patients, followed by distal muscle atrophy in seven (54%) patients. Tremors in the hand were a rare symptom seen in two patients. Claw hand was an atypical symptom seen in one patient. On cervical MRI, all patients showed excessive forward shifting of the posterior dura on flexion, with resultant cord compression due to tightness of the dural sac. One (8%) patient had no signs of myelopathy, while 12 (92%) patients had developed chronic myelomalacia and showed abnormal cord hyperintensity and atrophy in the lower cervical cord. All 13 (100%) patients showed increased laminodural space on flexion; the mean thickness was 4.08 mm, with the minimum and maximum thickness being 2.4 mm and 6.7 mm, respectively. Classifying by length of the anterior bulging dura, one (8%) patient showed involvement of less than two vertebral body segments, eight (62%) patients showed involvement of two to four vertebral body segments, and four (30%) patients showed involvement of more than four vertebral body segments. Crescent-shaped post-contrast enhancement on flexion was seen in all eight (100%) patients who underwent a contrast study. Prominent epidural flow voids on flexion were seen in six (46%) patients. Conclusions Hirayama disease is an uncommon type of cervical myelopathy seen typically in juvenile males. The occult onset of distal upper limb weakness and atrophy during puberty, typical MRI features of lower cervical cord atrophy, and the presence of a crescent-shaped enhancing mass in the posterior epidural space are pathognomonic of the condition. A few atypical cases can also occur. Early diagnosis and treatment are crucial to avoiding serious dysfunction.