Impact of various cervical surgical interventions in patients with Hirayama's disease-a narrative review and meta-analysis.

Hirayama disease (HD) is a relatively uncommon cause of lower cervical myelopathy. A number of surgical approaches have been described in patients with HD in literature. We reviewed the literature and did a systematic review and meta-analysis of the studies which presented the clinical outcome following surgical intervention in HD. A systematic search of literature was performed with the keywords "Surgical treatment in Hirayama Disease", "Surgical approach in Hirayama Disease" and "Hirayama disease surgery". Data related to clinical outcome following surgery was pooled to calculate the pooled proportion of clinical improvement following anterior and posterior surgical approach. Thirty-four articles met the inclusion criteria and were included in the final review. Altogether, there were 10 types of surgical procedures performed for Hirayama disease. The most commonly described surgical technique was anterior cervical discectomy and fusion with cervical plating. The pooled proportion of patients experiencing clinical improvement following all cervical approaches was 80% (95% confidence interval 76 to 84%). Pooled proportion was maximum for anterior cervical plating (96% (95% confidence interval 62 to 100%)) and minimum for ACDF without plating (57% (95% confidence interval 20 to 88%)). Subgroup analysis based on different surgical approaches was not significant (p value = 0.61). The pooled proportion of patients experiencing clinical improvement following anterior and posterior cervical approach was 80% (95% confidence interval 76 to 84%) and 81% (95% confidence interval 66 to 91%). The indications of surgical treatment in patients with HD include poor patient compliance for neck collar or rapidly progressing severe disease. Good results with more than 80% chances of clinical improvement have been reported following various anterior and posterior surgical approaches. However, there was no significant difference in the pooled outcome of different surgical approaches. Most common technique used in literature is anterior cervical discectomy and fusion with plating.

Surgical Management of Hirayama Disease (Monomelic Amyotrophy): Systematic Review and Meta-Analysis of Patient-Level Data.

BACKGROUND: Hirayama disease or juvenile-onset monomelic amyotrophy is a clinical syndrome that disproportionately affects young males. Standard of care revolves around conservative management, but some patients experience disease progression that may benefit from surgical intervention. METHODS: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review of previous reports of surgical treatment for Hirayama disease was performed. Studies were included if they provided individual patient-level data, described the clinical presentation and surgical intervention, and reported neurological improvement at last follow-up. Comparison between those who improved and those with stable symptoms at last follow-up was performed. Decision-tree analysis was used to identify the best predictors of neurological improvement by last follow-up. RESULTS: Of 624 unique articles, 30 were included in the qualitative review and 23 in the meta-analysis. Among the 70 patients in the meta-analysis, mean age was 21.2 ± 6.3 years, 91% were male, and mean symptom duration at presentation was 43.3 ± 61.8 months. Fifty-nine patients (84.3%) had improvement in their neurological symptoms by last follow-up. Univariable analysis showed the only significant predictor of improvement in neurological symptoms by last follow-up was the use of stabilization-alone versus decompression with or without stabilization. Baseline clinical symptoms nor radiographic features predicted outcome. Decision-tree analysis showed surgical strategy (stabilization-alone vs. decompression ± stabilization), age (<20 vs. ≥20), and surgical approach (anterior-only vs. posterior-only or anterior-posterior) predicted a higher likelihood of neurological improvement by last follow-up. CONCLUSIONS: Nearly 85% of patients experienced improvement in neurological symptoms. Improvement was best for those who underwent stabilization-alone, and decision-tree analysis suggested that the likelihood of improvement was also superior for patients under 20 years of age and those treated with an anterior versus posterior or staged approach.

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.

An Uncommon Presentation of Cervical Myelopathy.

Cervical myelopathy is a compressive spinal cord disease usually affecting individuals 55 and older. Involvement of C5-C7 is typical and classically presents with hand clumsiness, wide-based gait, and paresis. We present the case of a 38-year-old man with a pertinent history of a previous motor vehicle accident who presented to the emergency department for progressive numbness, weakness, and severe spasms in both lower extremities, and eventually developed bowel and bladder incontinence. Lumbar magnetic resonance imaging (MRI) showed moderate L3-L4/L5-S1 degenerative spinal changes; however, cervical MRI demonstrated severe C6-C7 spinal stenosis. The patient did not present with any upper extremity neurological changes. Given the relatively mild changes in the lumbar spine, the patient was concluded to have lower extremity and autonomic neurological issues due to severe cervical spinal stenosis. In this report, we present a relatively common case of cervical myelopathy and myelomalacia in a patient unusually presenting with no upper extremity signs and only lower extremity signs of progressive bilateral leg weakness and neurogenic urinary incontinence. This case emphasizes the importance of considering cervical spine workup in addition to thoracic and lumbar spine and conducting a comprehensive clinical neurological examination in the setting of lower extremity symptoms with progressive bilateral leg weakness and urinary incontinence.

[A case of proximal-type Hirayama disease associated with neck axial rotation].

Hirayama disease is characterized by juvenile onset of unilateral muscular atrophy of a distal upper extremity. The pathogenic mechanism of Hirayama disease is cervical cord compression by the posterior dura with forward displacement in the neck flexion position. A few cases of 'proximal-type Hirayama disease' have been described as showing muscular weakness and atrophy of the proximal upper extremities caused by the pathogenic mechanism similar to that of Hirayama disease. We report herein the case of a 16-year-old boy with proximal-type Hirayama disease, who developed symptoms after he began kyudo (Japanese traditional archery). Neurological examination revealed bilateral weakness of the muscles innervated by C5 and C6 segments (the deltoid, biceps brachii, brachioradialis), bilateral mild sensory disturbance in the radial side of the forearm, absent tendon reflexes of the biceps brachii and brachioradialis with preserved triceps reflex, pyramidal signs of the bilateral lower extremities (pathologically brisk reflexes of lower extremities, Babinski's signs). MR images in the neck flexion position showing expansion of the posterior extradural space and forward displacement of the spinal cord at the C3/4, C4/5, C5/6 and C6/7 disk levels. CT myelogram revealed spinal cord compression not only in neck flexion but also in neck left axial rotation. His symptoms improved after the restriction of neck flexion and axial rotation. Weakness of the upper extremities improved after 2 months. Pyramidal signs of the lower extremities disappeared after 18 months. The pathogenic mechanism in this case may be associated with not only neck flexion but also neck axial rotation.

Surgical Management of Hirayama Disease: A Rare Entity with Unusual Clinical Features.

Hirayama disease (HD) is a rare type of cervical myelopathy in young males due to neck flexion causing cervical cord atrophy and asymmetric flattening with preferential involvement of anterior horn cells of the spinal cord. This is due to forward displacement of the cord during neck flexion getting compressed between the posterior part of the vertebral body and the posterior dura. The spinal cord involvement occurs due to repeated flexion and extension motion of the neck leading to selective spinal cells injury and atrophy. Most cases report an asymmetric lower motor neuron type of weakness predominantly involving the forearm and hand muscles. We report here a case of HD in an 18-year-old male who presented to us with weakness and wasting in the right hand. The patient was progressively symptomatic over a period of 1 year before presentation. The etiology and the exact cause of HD largely remain debatable and rely on the understanding of few theories which have been put forward. The natural history of this disease reaches a plateau in terms of neurological involvement after 2-5 years and is considered a self-remitting disorder. The patient was initially managed with a cervical collar immobilization but symptoms were largely not improving which was attributed to poor brace compliance. The patient was then managed surgically with a posterior lateral mass instrumentation without fusion in a lordotic alignment at the levels of maximal dural shift anteriorly. The patient improved neurologically following the surgery and maintained the intact status at the last follow-up.

Cervical Flexion Myelopathy Eleven Years after a Cervical Spinal Cord Injury.

We herein describe a 37-year-old man who developed cervical flexion myelopathy 11 years after suffering a cervical spinal cord injury. Cervical magnetic resonance imaging 11 years after the accident demonstrated atrophy and hyperintense lesions at the C6 and C7 levels in the cervical cord with an abnormal alignment of the vertebrae. In the neck flexion position, an anterior shift of the cervical cord was evident. Our patient's condition suggests that an abnormal alignment of the cervical spine and spinal cord injury due to a traumatic accident could be risk factors in the subsequent development of cervical flexion myelopathy.

Tetraparesis as clinical correlate of subacute cervical flexion myelopathy.

CONTEXT: We report the case of a 20-year-old woman who underwent tracheal resection with postoperative chin-to-chest suture for 10 days, presenting with severe tetraparesis at our institution. Similar cases have been reported previously, however, not yet in the pathophysiological context of chronic cervical flexion myelopathy (Hirayama syndrome). FINDINGS: Extensive myelopathy at cervical level is the consequence of the fixed cervical spine position due to chin-to-chest suture. Predominantly affected young individuals (age range from 20-25 years) without evidence of degenerated spine disease suggest a similar mechanism as described in Hirayama syndrome-displacement of the dura with consecutive compression of the spinal cord vasculature. CONCLUSIONS: Subacute flexion myelopathy represents a serious complication of operative/postoperative fixed cervical spine positions, warranting particular attention by respective surgeons.

Cervical duraplasty with tenting sutures via laminoplasty for cervical flexion myelopathy in patients with Hirayama disease: successful decompression of a "tight dural canal in flexion" without spinal fusion.

OBJECT: Hirayama disease, juvenile muscular atrophy of the distal upper extremity, is a rare type of cervical flexion segmental myelopathy and its etiology is still being debated. Two theories have been proposed: a "contact pressure" theory and "tight dural canal in flexion" theory. Previously reported treatments, including conservative neck collar therapy and surgical spinal fusion, used fixation of the cervical spine with the aim of avoiding contact pressure between the cord and anterior structures. On the other hand, treatment by duraplasty without spinal fusion has also been used, which aims at decompressing a tight dural canal in flexion by preventing abnormal forward displacement of the posterior dura mater without restricting cervical motion in young patients. The authors developed a new surgical approach for treating a tight dural canal in flexion in patients with Hirayama disease: cervical duraplasty with tenting sutures via laminoplasty without spinal fusion. With this treatment they aimed to both decompress the spinal cord and preserve as much cervical motion as possible. The purpose of this study was to assess the clinical outcomes of patients who underwent this new surgical procedure and to investigate the etiology of Hirayama disease. METHODS: Six male patients (age range 17-23 years) with Hirayama disease underwent surgery between 2006 and 2012. The pre- and postoperative anteroposterior diameters of the dural canal in the flexed neck position, grip strength of the bilateral upper extremities, cervical alignment (C2-7), and cervical local flexion range of motion were compared. The presence or absence of surgical complications was assessed. To investigate the comparison group of Hirayama disease treated with spinal decompression, the PubMed database was searched for all relevant English-language case reports and series published between 1990 and 2013. RESULTS: The postoperative anteroposterior diameters of the dural canal were significantly expanded in the flexed neck position (7.2 ± 2.2 mm preoperatively vs 9.8 ± 1.7 mm postoperatively, p = 0.001). Grip strength of the upper extremities significantly improved bilaterally (20 ± 14 kg preoperatively vs 26 ± 15 kg postoperatively, p = 0.001). No significant difference was observed between pre- and postoperative cervical alignment in the neutral neck position (7.7° ± 8.1° preoperatively vs 9.0° ± 7.7° postoperatively, p = 0.74) or the cervical local flexion angle in the flexed neck position at the corresponding level of laminoplasty (16.6° ± 5.1° preoperatively vs 15.0° ± 9.4° postoperatively, p = 0.8). No surgical complications were noted, except for transient CSF leakage, which was resolved after lumbar drainage. The systematic review identified 37 cases from 7 reports: 26 with spinal fusion only, 5 with duraplasty without fusion, and 6 with combined duraplasty and fusion. In the largest series, in which 12 cases were treated with anterior fusion, cervical alignment was maintained, but local flexion motion was significantly decreased as a result of fixation. Although significant improvements in or stabilization of grip strength occurred in all 7 reported studies regardless of decompression procedures, one major delayed surgical complication was noted in a patient treated with anterior fusion. The patient developed severe kyphotic changes, which required reconstruction surgeries. CONCLUSIONS: Cervical duraplasty with tenting sutures via laminoplasty prevented abnormal forward displacement of the posterior dura mater while preserving normal anterior structures and flexion motion of the cervical spine without major surgical complications. The clinical improvements achieved by the authors' method support evidence that a tight dural canal in flexion largely contributes to segmental myelopathy in patients with Hirayama disease.

Effect of neck flexion on somatosensory and motor evoked potentials in Hirayama disease.

UNLABELLED: Hirayama disease (HD) is a rare motor disorder mainly affecting young men, characterized by atrophy and weakness of forearm and hand muscles corresponding to a C7-T1 myotome distribution. The weakness is usually unilateral or asymmetric and progression usually stops within several years. The etiology of HD is not well understood. One hypothesis, mainly based on MRI findings, is that the weakness is a consequence of cervical flexion myelopathy. The aim of this study was to explore the function of corticospinal and ascending somatosensory pathways during neck flexion using evoked responses. MATERIALS AND METHODS: 15 men with HD and 7 age-matched control male subjects underwent somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) studies with the neck in neutral position and fully flexed. SSEP studies included electrical stimulation of median and ulnar nerves at the wrist, and tibial nerve at the ankle with recording over the ipsilateral Erb's point, cervical spine, and contralateral sensory cortex. MEP recordings were obtained by magnetic stimulation of the motor cortex and the cervical lower spinal roots; the evoked responses were recorded from the contralateral thenar and abductor hallucis muscles. RESULTS: MEP recordings demonstrated significant lower amplitudes, and slightly prolonged latencies in HD patients on cervical stimulation, compared to control subjects. During neck flexion, MEP studies also demonstrated a statistically significant drop in mean upper limb amplitude on cervical stimulation in HD patients, as well as in control subjects, although to a lesser degree. In contrast, no significant differences were found in SSEP studies in HD patients compared to control subjects, or between neutral and flexed position in these groups. CONCLUSION: The study shows a negative effect of cervical flexion on MEP amplitudes in HD patients as well as in control subjects, requiring more studies to investigate its significance. Neck flexion did not have an influence on any SSEP parameters in patients or controls.