A clinical study of hirayama disease in Taiwan

Correlation Study Between Spinal Cord Function, Spinal Cord Morphology and Cervical Spine Alignments in Patients With Hirayama Disease

OBJECTIVE

This study aimed to explore the relationship between diffusion tensor imaging (DTI) parameters, cervical spine alignments, and spinal cord morphological parameters in patients with Hirayama disease (HD).

METHODS

In this retrospective cohort study, 41 HD patients were recruited from the Huashan hospital from July 2017 to November 2021. Patients received X-rays, conventional magnetic resonance (MR), and DTI scans in flexion and neutral positions. The DTI parameters assessed were calculated using the region of interest (ROI) method. Paired t-tests were performed on the DTI parameters of neck flexion and neutral position. Cervical spine alignments, including flexion and neutral Cobb angles, were measured, and range of motion (ROM) was calculated. Spinal cord morphological parameters were measured, including spinal cord atrophy (SCA) and loss of attachment (LOA). Spearman's correlation analysis between DTI parameters, cervical spine alignments, and spinal cord morphological parameters was performed.

RESULTS

In comparing DTI parameters, segments of the C3/4, C4/5, C6/7, and lower cervical spine were significantly different, while segments of C5/6 were not significantly different. In Spearman's correlation analysis, the flexion Cobb angle was significantly correlated with the fractional anisotropy (FA) value (R2 = .111, P = .033) and apparent diffusion coefficient (ADC) value (R2 = .119, P = .027). Flexion FA values were correlated with SCA in C4/5 (R2 = .211, P = .003), C5/6 (R2 = .454, P < .001), and C6/7 (R2 = .383, P < .001) while flexion ADC values were correlated with SCA in the C4/5 (R2 = .178, P = .006), C5/6 (R2 = .388, P < .001) and C6/7 segments (R2 = .187, P = .005).

CONCLUSION

The DTI parameters were correlated with the flexion Cobb angle and the SCA. These data support the dynamic cervical flexion compression hypothesis and indicate that the degree of SCA may be used to assess the condition of HD patients quantitatively.

Characteristics of Hirayama Disease in Young South Korean Soldiers

BACKGROUND AND PURPOSE

The purpose of this study was to describe the clinical presentation and features in electrodiagnostic and imaging investigations of young South Korean males diagnosed with Hirayama disease (HD).

METHODS

We reviewed the electronic medical records of South Korean enlisted soldiers who were diagnosed with HD and discharged from military service during 2011-2021. We investigated the clinical characteristics and results of electrodiagnostic and magnetic resonance imaging (MRI) investigations. We analyzed laterality and identified the involved muscles using needle electromyography (EMG). Loss of lordosis, localized cervical cord atrophy, loss of attachment between the posterior dura and subjacent lamina, asymmetric flattening of the cord, crescent-shaped mass in the posterior epidural space, and noncompressive intramedullary T2-weighted high signal intensity were investigated using neutral- or flexion-position MRI.

RESULTS

Forty-two male patients aged 20.2±0.8 years (mean±standard deviation) were identified. All patients complained of hand weakness, and 10 complained of hand tremor (23.8%). Four patients (9.5%) had symptoms in both upper limbs, and five (11.9%) had sensory disturbances. Needle EMG revealed that muscles in the C7-T1 myotome were commonly involved, and C5-C6 involvement of the deltoid (10.5%) and biceps brachii (12.5%) was also observed. In cervical MRI, localized cord atrophy (90.0%) was the most characteristic finding, and cord atrophy was most severe at the C5-C6 level (58.3%).

CONCLUSIONS

This is the first description of a large number of patients with HD in South Korea. The clinical presentation and features found in electrodiagnostic and imaging investigations will improve the understanding of HD in the young South Korean male population.

Hirayama's disease associated with cervical deformity and spinal cord compression: a case report from Sweden

BACKGROUND

Hirayama's disease (HD) is most common in young males, and previous studies are predominantly from Asian countries. The cause of HD is unknown but the most common theory about the pathology speculates on forward bending that causes a compression of the dura mater and the anterior horn of the spinal cord against the vertebra during an overstretch flexion that may result in myelopathy. Both anterior and posterior cervical surgical approaches have been shown to be effective in stopping the disease and improving function; however, HD is also reported to be a self-limited disease, and treatment with a cervical collar may be an alternative for these patients.

CASE REPORT

We report HD in a 17-year-old male from Sweden who underwent surgical treatment with a 2 level anterior cervical discectomy and fusion (ACDF) due to neurological progression from HD after conservative treatment.

CONCLUSION

HD is rare and is easily overlooked. Surgical intervention shows promising results for neurological progression, but HD is also reported to be a self-limited disease.

Single-institution Series of Hirayama Disease in North America

STUDY DESIGN

A retrospective chart review.

OBJECTIVE

The aims of this study were to review pathophysiology, workup, and treatment for Hirayama disease (HD); and to assess outcomes from a single institution.

SUMMARY OF BACKGROUND DATA

HD is a rare, painless, cervical myelopathy with distal upper extremity weakness, muscle wasting, and spinal cord atrophy. Disease progression-a consequence of repeat flexion injury-occurs up to 5 years from the initial diagnosis.

METHODS

Single-institution review of pediatric HD patients from 2010 to 2020.

RESULTS

Patients (n=10 male, n=2 female) presented in the second decade (14-20 y) with painless progressive distal upper extremity weakness and atrophy without sensory loss. Electromyography (n=12) demonstrated denervation in C7-T1 myotomes and flexion/extension magnetic resonance imaging showed focal cord atrophy and anterior displacement of the posterior dura with epidural enhancement in flexion. Treatment included observation and external orthoses (n=9) and anterior cervical discectomy with fusion (n=3). One of the 9 patients managed conservatively experienced further deterioration; no patient who underwent anterior cervical discectomy with fusion progressed.

CONCLUSIONS

Patients with HD require a multidisciplinary approach to diagnosis and treatment to preserve function. Treatment is preventive and aims to minimize flexion injury by inhibiting motion across involved joints. First-line management is avoidance of neck flexion and use of rigid orthosis; in cases of failed conservative management and/or rapid clinical deterioration, surgical fixation can be offered.

Laminoplasty with tented duraplasty for Hirayama disease

BACKGROUND

Hirayama disease (HD) is a characterized by progressive amyotrophy of the upper limbs due to a forward displacement of the cervical dura during neck flexion.

METHODS

Unlike other treatment options aiming at preventing cervical flexion (e.g., collar or arthrodesis), laminoplasty with tented duraplasty addresses dural dysplasia. Technically, the procedure consists in enlarging the dural sac by performing an expansile duraplasty that is secured to the yellow ligaments, in association with an open-book laminoplasty.

CONCLUSION

Laminoplasty with tented duraplasty is a surgical option addressing the cause of HD to prevent further neurological deterioration while preserving cervical motion.

It's in the game: A review of neurological lesions associated with sports

INTRODUCTION

The practice of sports may lead to neurological injuries. While relatively uncommon (overall incidence of approximately 2.5%), and mostly benign and transient, some conditions may be life-threatening and permanent. Thus, both clinical neurologists and sports physicians should be aware of their existence and relevance. We aimed to review all sports-related neurological injuries and illnesses reported in the literature.

METHODS

Following SANRA guidelines, we performed a narrative review and searched PubMed and Scopus databases. Relevant sports were selected based on their recognition as an Olympic sport by the International Olympic Committee. Chronic traumatic encephalopathy (CTE) and other neurodegenerative disorders were not included.

RESULTS

A total of 292 studies were included concerning 33 different sports. The most reported neurological injury was damage to the peripheral nervous system. Traumatic injuries have also been extensively reported, including cerebral haemorrhage and arterial dissections. Non-traumatic life-threatening events are infrequent but may also occur, e.g. posterior reversible encephalopathy syndrome, cerebral venous thrombosis, and arterial dissections. Some conditions were predominantly reported in specific sports, e.g. yips in baseball and golf, raising the possibility of a common pathophysiology. Spinal cord infarction due to fibrocartilaginous embolism was reported in several sports associated with minor trauma.

CONCLUSION

Sports-related neurological injuries are increasingly receiving more social and medical attention and are an important cause of morbidity and mortality. This review may serve as a guide to physicians managing these challenging situations.

Changes in Self-Esteem in Patients with Hirayama Disease and its Association with Prognosis After Anterior Cervical Fusion Procedures

OBJECTIVE

To quantify self-esteem in patients with Hirayama disease (HD) and investigate the impact of this psychosocial factor on surgical outcomes in HD.

METHODS

The Rosenberg Self-Esteem Scale (RSES) was measured in 58 patients with HD before anterior cervical fusion. These patients further underwent motor unit number estimation, handgrip strength, disabilities of the arm, shoulder and hand (DASH), Beck Anxiety Inventory (BAI) and Beck Depression Index (BDI) before and 18 months after operation. Furthermore, the International Physical Activity Questionnaire (IPAQ) was administered to all patients at postoperative 18-month assessments.

RESULTS

Compared with the general population, patients with HD showed a relatively lower RSES, and RSES was negatively associated with both postoperative DASH (r = -0.431, P < 0.05) and preoperative to postoperative changes (r = -0.295, P < 0.05) and positively associated with IPAQ (r = 0.472, P < 0.05). Similar to the difference in postoperative DASH scores, more patients with low self-esteem felt postoperative aggravated motor dysfunction than those with high/normal self-esteem (P < 0.05). Postoperative BDI exerted a partial mediating effect on the relationship between RSES and DASH scores (B = -0.30, P < 0.05), and postoperative BAI played a partial mediating effect on the relationship between RSES and IPAQ scores (B = 0.30, P < 0.05).

CONCLUSIONS

The self-esteem of HD patients may be below the population norms. Importantly, relatively low self-esteem in HD patients may cause/worsen postoperative depression and anxiety, thereby resulting in poor self-reported surgical prognosis and an inactive lifestyle after operation. Therefore, perioperative treatment and rehabilitation efforts in HD patients, especially those with low self-esteem, should account for both physiological and psychological symptoms.

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.

Atypical Presentation of Hirayama Disease Involving the Cervico-Thoracic Segment Causing Diagnostic Dilemma: A Case Report

Hirayama disease, also known as monomelic amyotrophy, usually affects young males who initially experience increasing muscle weakness and atrophy of the distal upper limb before experiencing a sudden plateauing of symptom progression a few years later. It is a form of cervical myelopathy characterized by self-limiting, asymmetrical lower motor weakness of the upper limbs affecting the hands and forearms. This condition is brought on by the cervical dural sac and spinal cord being abnormally displaced forward during neck flexion, which causes the anterior horn cells to atrophy. However, research into the precise process is ongoing. Patients presenting with such features with additional atypical symptoms, like back pain, weakness, atrophy and paresthesia of lower extremities cause a diagnostic dilemma. We describe a case of a male patient, age 21, who complained of weakness in both upper limbs mostly on the hand and forearm muscles along with weakness and deformity in both lower limbs. He was diagnosed with atypical Cervico-thoracic Hirayama disease and treated.

Juvenile muscular atrophy of the distal upper extremity (Hirayama syndrome): a systematic review

INTRODUCTION

Hirayama syndrome is likely caused by a forward displacement of the posterior dura during cervical flexion leading to changes in the muscles of the fingers and wrist. The aim of this systematic review was to document the number of reported cases, the necessity of dynamic MRI of the cervical spine and the subsequent treatment.

METHODS AND MATERIALS

A systematic review was conducted and the Pubmed/Medbase, Cochrane, Google, Embase and Ovid database were searched for (Hirayama) AND ((disease) OR (syndrome)). A total of 42 studies were included for analysis reporting 2311 patients.

RESULTS

The mean age was 20.2 ± 2.26 years and predominantly males (92.8%) were identified. On MRI the "snake eyes" appearance of the spinal cord was present in 27.8% and the typical time between onset of symptoms and diagnosis was 41.5 ± 16.4 months. A variety of different treatments have been reported, although there is no substantial evidence that any of them are superior to observation.

CONCLUSION

The delay in diagnosis from initial presentation of symptoms shows that this condition may be underdiagnosed in a variety of cases. Further, this study shows the necessity of either a dynamic MRI in flexion or a static MRI scan in neutral position and in flexion, to identify functional spinal and/or foraminal stenosis for a prompt diagnosis and subsequent treatment.

Do patients with Hirayama disease require surgical treatment? A review of the literature

The main clinic characteristic of Hirayama disease (HD) is atrophy of the distal muscles in the upper limbs. Recently, an increasing number of HD cases have been reported. Many HD patients have persistently progressive symptoms and conservative treatments failed. This article aims to review the current status of the field and summarizes the main surgical treatment options for patients with HD. A comprehensive search of the PubMed and the Web of Science databases was conducted from their inception to September 15th, 2022. Search terms included "juvenile muscular atrophy of upper extremity", "Hirayama disease" and "surgery". A total of 169 relevant publications were identified and 29 articles were finally reviewed. Current surgical treatments for HD are either anterior cervical surgery or posterior cervical surgery. The two approaches can effectively stop the disease. However, no studies have compared the advantages and limitations of the two surgical methods. The previous view that HD can be improved with conservative treatment has been challenged. In many studies, surgical treatment has been shown to improve the hand function in patients with HD. However, there is still controversy about the methods of anterior and posterior cervical surgery. Future research could focus on exploring the advantages and limitations of different surgeries.

Can preoperative cervical spinal diffusion tensor imaging (DTI) indices predict surgical outcomes in patients with Hirayama disease? A retrospective cohort study

Objective

Anterior cervical discectomy and fusion (ACDF) surgery can effectively prevent disease progression in patients with Hirayama disease (HD) and diffusion tensor imaging (DTI) can quantitatively assess spinal cord function. In this study, we aimed to evaluate the relationship between preoperative spinal DTI indices and the clinical outcomes of patients with HD when treated by ACDF.

Methods

We retrospectively analyzed 35 HD patients treated by ACDF. We collated a range of DTI indices, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values, prior to surgery with patients in flexion and neutral positions. Patients were divided into improvement (Im) group and non-improvement (Nim) group according to the Odom score, and the difference in surgical outcomes between the two groups was confirmed by quick disabilities of the arm, shoulder and hand (Q-DASH) scores. The DTI indices in the two groups of patients were then compared. Receiver operating characteristic (ROC) curves and area under curve (AUC) were used to evaluate the predictive capability. The correlation between Q-DASH scores and DTI indices was also evaluated.

Results

The FA values in the two groups of patients differed significantly in the cervical flexion position and the different segments were mainly located in the lower cervical spinal cord including the flexion C5/6 (Im group vs. Nim group: 0.501 ± 0.078 vs. 0.362 ± 0.087, P < 0.001) and C6/7 (Im group vs. Nim group: 0.455 ± 0.097 vs. 0.347 ± 0.102, P = 0.003) FA values, the mean FA value for C4/5-C6/7 (Im group vs. Nim group: 0.471 ± 0.067 vs. 0.372 ± 0.078, P < 0.001), mean FA value for C5/6-C6/7 (Im group vs. Nim group: 0.478 ± 0.076 vs. 0.354 ± 0.083, P < 0.001) and mean FA value for the two minimal segments (Im group vs. Nim group: 0.442 ± 0.078 vs. 0.341 ± 0.081, P = 0.001). The ADC values were similar to FA values. The ROC curve for DTI indices in the lower cervical spinal cord had an AUC > 0.7 including: flexion FA value and ADC value for C5/6 (0.877 and 0.931), flexion FA value and ADC value for C6/7 (0.778 and 0.761), flexion mean FA value and ADC value for C4/5-C6/7 (0.846 and 0.859), flexion mean FA value and ADC value for C5/6-C6/7 (0.861 and 0.905), flexion mean FA value and ADC value for the two minimal/maximal segments (0.815 and 0.892). DTI indices including FA value and ADC value were correlated with the preoperative score, final follow-up score and improvement percentage. Flexion ADC value was correlated with improvement score but flexion FA value was not correlated with improvement score.

Conclusion

Preoperative DTI indices of the spinal cord, especially those of the lower cervical spinal cord with patients in the flexion position, can predict the clinical outcome of patients with HD post-surgery. In general, a larger FA value and a smaller ADC value indicate a better surgical outcome.

Hirayama disease with proximal upper limb involvement in an adolescent female: A case report

INTRODUCTION AND IMPORTANCE

Hirayama disease is a rare benign motor neuron disorder that involves a single upper limb. It affects the lower cervical myotomes and presents clinically by muscle wasting and weakness.

CASE PRESENTATION

We report the case of a 17-year-old female who presented with a four weeks history of progressive weakness of the left upper limb. The blood investigations and image reported unremarkable findings. Patient improved on physiotherapy.

CLINICAL DISCUSSION

Hirayama disease is rarely encountered in clinical settings and should be suspected in female patients presenting with unilateral or asymmetrical bilateral lower motor weakness of hands and forearms.

CONCLUSION

We present a rare condition in a 17-year-old female with a left upper extremity monomelic amyotrophy, a Hirayama disease.

Supercharged End-to-Side Anterior Interosseous to Ulnar Motor Nerve Transfer for Hirayama Disease: A Case Report

Hirayama disease is a rare condition of cervical myelopathy. Its early identification and correction can optimize functional outcomes. However, late presentation and some more severe cases may be associated with loss of hand function. Among the cases described, there are no reports of nerve transfers for this condition. We presented the first case report of a Hirayama disease of isolated ulnar nerve impairment managed with nerve transfer. Electroneuromyography showed isolated preganglionic involvement of C7, C8, and T1, with no sensory changes. The patient underwent nerve transfer with anterior interosseous nerve to ulnar nerve supercharge end-to-side, recovering hand function in 7 months.

Interobserver and Intraobserver Reproducibility and Reliability of the Huashan Clinical Classification System for Hirayama Disease

Purpose: The Huashan clinical classification system for Hirayama disease has recently been proposed and has been found useful for diagnosis and treatment. So far, however, there has been little in-depth evaluation of its reliability. Thus, this study aimed to assess the reproducibility and reliability of the system. Methods: Patients diagnosed with Hirayama disease between 2019 and 2020 were recruited. Seven spine surgeons from four different institutions, including an experienced group of three and an inexperienced group of four, were trained as observers of the Huashan clinical classification system for Hirayama disease, and these surgeons classified the recruited patients using the system. Then, 2 months later, they repeated the classification on the same patients in a different order. The interobserver and intraobserver agreement between the results was analyzed using percentage agreement and weighted kappa (κ) statistics. Results: A total of 60 patients were included in the analysis. For all the observers, experienced observers, and inexperienced observers, the agreement percentages were, respectively, 78.5% (κ = 0.76), 80.0% (κ = 0.78), and 78.9% (κ = 0.77), indicating substantial interobserver reproducibility. For distinguishing typical (Types I and II) and atypical (Type III) Hirayama disease among the different groups of observers, the percentage agreement ranged from 95.6 to 98.9% (κ = 0.74-0.92), indicating substantial to nearly perfect reproducibility. For suggesting conservative treatment (Types I and III) or surgery (Type II), the percentage agreement ranged from 93.3 to 96.4% (κ = 0.81-0.90), indicating nearly perfect reproducibility. As for intraobserver agreement, the percentage agreement ranged from 68.3 to 81.7% (κ = 0.65-0.79), indicating substantial reliability. Conclusion: The Huashan clinical classification system for Hirayama disease was easy to learn and apply in a clinical environment, showing excellent reproducibility and reliability. Therefore, it would be promising to apply and promote this system for the precise and individualized future treatment of Hirayama disease.

Quantitative assessment of motor impairment and surgical outcome in Hirayama disease with proximal involvement using motor unit number index

OBJECTIVE

To assess the feasibility of motor unit number index (MUNIX) in quantitatively evaluating Hirayama disease (HD) with proximal involvement and to identify the effectiveness of anterior cervical fusion (ACF) in treating atypical HD with proximal involvement.

METHODS

This study included 28 atypical HD patients with proximal involvement (proximal-distal vs. distal-proximal groups: 5 vs. 23) and 41 healthy controls. All patients underwent pre- and postoperative 1-year MUNIX tests on abductor pollicis brevis (APB), abductor digiti minimi (ADM), biceps brachii (BB) and deltoid (Del). The disabilities of arm, shoulder and hand (DASH) and Medical Research Council (MRC) scales were also performed in these patients before and one year after operation.

RESULTS

Preoperatively, the patients in the distal-proximal group showed reduced compound muscle action potential (CMAP), decreased MUNIX and increased motor unit size index (MUSIX) in bilateral distal muscles and symptomatic-side proximal muscles (P < 0.05), and similar abnormalities were also observed in ADM, BB and Del on the symptomatic side in the proximal-distal groups (P < 0.05). Postoperative follow-up analysis identified increased MUNIX in the symptomatic-side proximal muscles with improved motor function in the proximal-distal groups (P < 0.05), and distal-proximal group patients showed an increase in both CMAP and MUSIX in the symptomatic-side proximal muscles (P < 0.05).

CONCLUSIONS

MUNIX may serve as an available supplementary test to quantitatively evaluate the motor dysfunction and treatment outcome in HD with proximal involvement. ACF procedures can effectively treat these atypical HD patients, especially for those whose symptoms started in proximal muscles.

Hirayama Disease: An Important Cause of Focal Hand Weakness in Young Adults

Patients with progressive hand weakness may be seen in ambulatory medical clinics or in emergency rooms due to direct effects on activities of daily living or inadvertent injury associated with overuse or attempts to maintain normal function. It is important to recognize potential cause(s) and perform appropriate diagnostic tests and referrals that aid guide appropriate treatment that may lead to good outcomes. Hirayama disease is an underrecognized disorder in young adults due to an asymmetric growth-associated cervical spinal cord compression injury. Awareness of this disorder by internists, emergency room physicians, and radiologists would prevent unnecessary tests and interventions that may contribute to disease progression by delaying appropriate treatments or treating inappropriately, with consequential effects on outcomes. In this article, we describe 3 Hirayama disease cases from a single tertiary care institution and demonstrate how delayed diagnosis affected outcomes in 2 patients and early recognition facilitated improved outcomes in a patient.

The Influence of "Loss of Attachment" on the Outcome of Anterior Cervical Fusion Procedures in Patients With Hirayama Disease

The objective of this study was to identify the influence of the measurements of "loss of attachment" on the surgical outcome in Hirayama disease (HD). Forty-two patients with HD underwent neutral and cervical-flexion magnetic resonance imaging (MRI) before surgery, and the cervical-flexion MRI was repeated at the 3-month postoperative visit. The longitudinal separation range (LSR) of loss of attachment, the maximum forward-shifting (MFS) degree in the cervical cord, and the relative morphological changes of the cervical cord were measured on MRI. Additionally, all patients underwent handgrip strength (HGS) testing, the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, and Medical Research Council scales at the 1-year postoperative visit. Postoperatively, the cervical-flexion X/Y and the LSR decreased significantly at a mean of 94.17±8.65 days (range, 75-110 days) (P<.01), while the cervical-flexion A/B increased (P<.01). Loss of attachment was resolved in fused segments in all 42 patients, but there were 7 instances of residual loss of attachment at adjacent segments. Twenty (47.6%) of the 42 patients' DASH scores decreased at the 1-year postoperative visit. According to the logistic regression analysis, both LSR and MFS were related to the surgical outcomes. Receiver operating characteristic curve analysis found that area under the curve and cutoff values were 0.959 and 4.5, respectively (P<.05) for LSR and 0.782 and 0.215, respectively (P<.05) for MFS. Anterior cervical fusion procedures can effectively improve the abnormal loss of attachment and prevent further progression of HD. The LSR is an important risk factor for the prognosis, and longer fused segments may be required when the LSR is 5 segments or more. [Orthopedics. 2021;44(1):30-37.].

Effect of strengthening exercises in Hirayama disease: a case study

Background/Aims

The effects of strengthening exercises in patients with Hirayama disease are not well documented. This case study examined the effect of strengthening exercises on hand functions in a patient with Hirayama disease.

Methods

An 18-year-old man with weakness in the right hand was given a hand-function strengthening programme consisting of 40 minutes of exercises, which were performed 5 days a week over an 8-week period. The patient used theraputty, a gel ball, finger dexterity board, gym kit and hand grip exerciser. The effects of the programme were evaluated using manual muscle testing, a hand-held dynamometer, pinchometer and the Minnesota Manual Dexterity Test.

Results

The patient's manual muscle testing grades improved following the strengthening programme. Results from the Dynamometer, pinchometer and Minnesota Manual Dexterity Test objectively exhibited increased muscle strength and improved hand functions.

Conclusions

Strengthening exercises are effective in alleviating muscle weakness and improving hand functions associated with Hirayama disease.

Monomelic Amyotrophy (Hirayama Disease): A Rare Case Report and Literature Review

Hirayama disease is a rare neurological entity that is characterized by initial progressive muscular wasting and weakness of the distal upper limb in young men, followed by a spontaneous arrest within several years. The disease is believed to be a result of forward displacement of the cervical dural sac and spinal cord induced by neck flexion. It is commonly seen in Asia and rarely encountered in the Middle East countries. We report a rare case of a 20-year-old Kuwaiti patient presenting with a 10-month duration of gradual left upper limb weakness and wasting. We describe his electrophysiological and radiological findings that confirmed the diagnosis, and conducted a literature review. Hirayama disease is rarely encountered in clinical settings and should be suspected in male patients presenting with unilateral or asymmetrical bilateral lower motor weakness of hands and forearms. It is a benign entity, and cervical collar is usually the only treatment needed in most cases.

Diffusion Tensor Imaging Characteristics in Hirayama Disease: Case Report and Review of the Literature

BACKGROUND

Hirayama disease (HD) is a rare focal amyotrophy, commonly reported in adolescent Asian males and characterized by unilateral or asymmetric distal upper extremity weakness. This disease exhibits an indolent course of progression over the initial 3-4 years, followed by a stage of stabilization. The diagnosis is confirmed by demonstration of enhanced posterior epidural space and dynamic spinal cord compression on cervical flexion magnetic resonance imaging. Diffusion tensor imaging (DTI) is a functional imaging modality, which can potentially be utilized in the diagnosis of HD.

CASE DESCRIPTION

We hereby report 2 young male patients who had presented to us with bilateral asymmetric upper extremity weakness. In both patients, magnetic resonance imaging of cervical spine revealed spinal cord atrophy or myelomalacia, anterior displacement of posterior thecal sac, and T2 hyperintense posterior epidural space, all of which were more evident in flexed position. On DTI, we could observe reduced fractional anisotropy in cervical flexion, as compared with neutral.

CONCLUSIONS

DTI tractography and reduced fractional anisotropy in cervical flexion can serve as potential indicators for the diagnosis of HD. Large-scale studies in the future are necessary to identify the potential role of this modality in surgical decision-making and in the assessment of prognosis in patients with HD.

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.

The evaluation on neural status of cervical spinal cord in normal and Hirayama disease using diffusion tensor imaging

PURPOSE

To explore the changes in diffusion tensor imaging (DTI) parameters in cervical spinal cord in Hirayama disease (HD) patients and healthy volunteers and to compare these parameters between cervical flexion and neutral positions in HD patients.

METHODS

Seventeen male patients with HD and eleven healthy young males were included to receive DTI scans in cervical flexion and neutral positions. The FA and ADC values of different levels were measured based on the region of interest drawn on the mid-sagittal plane. The dynamic compressed level's parameters were defined as the lowest and the second lowest FA and the highest and the second highest ADC, respectively. The clinical assessment of patients was obtained using their disabilities of the arm, shoulder and hand (DASH) scores.

RESULTS

For the HD patients, the FA values in the cervical flexion position were lower and the ADC values were much higher than those in the cervical neutral position. Compared with the controls, the ADC values were significantly higher in the lower levels (C5/6-C7/T1) and the FA values obviously lower at C7/T1 in HD patients in cervical neutral position. The FA and ADC values of the dynamic compressed level in HD patients deviated significantly from the average of the lower levels in controls. Both the FA and ADC values of the dynamic compressed level correlated with the DASH scores (FA, R² = 0.520, P = 0.001; ADC, R² = 0.421, P = 0.005).

CONCLUSIONS

DTI parameters can support a hypothesis of dynamic cervical flexion compression and noninvasively reveal the neural status of HD patients. These slides can be retrieved under Electronic Supplementary Material.

CAN anterior cervical fusion procedures prevent the progression of the natural course of Hirayama disease? An ambispective cohort analysis

OBJECTIVE

To clarify the effectiveness of anterior cervical fusion (ACF) in the treatment of Hirayama disease (HD).

METHODS

Sixty-nine HD patients who accepted ACF procedures underwent dynamic F-waves before and soon after operation, and 36 of the 69 patients underwent pre- and postoperative magnetic resonance imaging (MRI). Motor unit number estimation, handgrip strength (HGS) and disabilities of arm, shoulder and hand (DASH) were performed in these 36 HD patients and in the other 24 patients who accepted neither neck-collar support nor operation, and these tests were reassessed about one year after initial test.

RESULTS

Postoperatively, dynamic F-wave abnormalities were observed in fewer HD cases (2/69 vs. 25/69), and neck-flexion MRI abnormalities decreased significantly (P < 0.05). Compared with motor unit loss in patients who were untreated, follow-up analysis demonstrated no differences in motor unit, HGS or DASH in HD patients who underwent operation (P > 0.05), and mild recovery of motor units was observed in patients with preoperative abnormal dynamic F-waves (P < 0.05).

CONCLUSIONS

ACF procedures can immediately remove neck-flexion abnormalities and prevent or delay the progression of HD.

SIGNIFICANCE

ACF procedures may provide effective, reliable and alternative methods for the treatment of HD, especially in HD patients with functional evidence of neck-flexion abnormalities.

Dynamic Cervical Radiographs in Patients with Hirayama Disease: An Unneglectable Factor on the Choice of Surgery Options

OBJECTIVE

To evaluate the cervical spine alignment and range of motion (ROM) of neck flexion in patients with Hirayama disease.

METHODS

Fifty male patients were included, with dynamic radiographs and magnetic resonance imaging (MRI) analyzed retrospectively. The Cobb angles for the entire cervical spine (C2-C7) and each level (C2/3-C6/7) were measured, and the neck flexion ROM was defined as the neutral Cobb angle minus the flexion Cobb angle. Paired t tests and Wilcoxon signed-rank tests were used to compare the Cobb angles and ROM between radiographs and MRI.

RESULTS

The neutral and flexion Cobb angles decreased from C2/3 to C5/6 but increased at C6/7 on radiographs and MRI. The neutral Cobb angle of C2-C7 from radiographs was significantly larger than that seen on MRI (5.27° vs. -3.26°; P < 0.0001). Neck flexion ROM seen with MRI tended to be lower than those of corresponding levels on radiographs. The ROM of C2-C7, C3/4, and C6/7 on radiographs was significantly larger than that seen with MRI (37.86° vs. 26.59°, P < 0.0001; 7.46° vs. 5.10°, P = 0.0071; and 10.45° vs. 7.03°, P = 0.0023, respectively). For the lower cervical levels, the largest and second largest ROM were seen in C5/6 and C6/7 on the radiographs but C5/6 and C4/5 on MRI.

CONCLUSIONS

The cervical spine alignment and neck flexion ROM in Hirayama disease differed between radiographs and MRI. Both imaging techniques should be examined comprehensively when planning an operation.

Hirayama Disease with Proximal Involvement

Hirayama disease is a slowly progressing benign motor neuron disease that affects the distal upper limb. A 29-year-old man visited the hospital with a 1-year history of weakened left proximal upper limb. He was diagnosed with Hirayama disease 9 years ago, while there was no further progression of the muscle weakness afterward. Atrophy and weakness was detected in proximal upper limb muscles. Magnetic resonance imaging and somatosensory evoked potentials were normal. Needle electromyography showed abnormal findings in proximal upper limb muscles. Our patient had Hirayama disease involving the proximal portion through secondary progression. Clinical manifestation and accurate electromyography may be useful for diagnosis. Rare cases with progression patterns as described here are helpful and have clinical meaning for clinicians.

Amyotrophic lateral sclerosis and motor neuron syndromes in Asia

While the past 2 decades have witnessed an increasing understanding of amyotrophic lateral sclerosis (ALS) arising from East Asia, particularly Japan, South Korea, Taiwan and China, knowledge of ALS throughout the whole of Asia remains limited. Asia represents >50% of the world population, making it host to the largest patient cohort of ALS. Furthermore, Asia represents a diverse population in terms of ethnic, social and cultural backgrounds. In this review, an overview is presented that covers what is currently known of ALS in Asia from basic epidemiology and genetic influences, through to disease characteristics including atypical phenotypes which manifest a predilection for Asians. With the recent establishment of the Pan-Asian Consortium for Treatment and Research in ALS to facilitate collaborations between clinicians and researchers across the region, it is anticipated that Asia and the Pacific will contribute to unravelling the uncertainties in ALS.

Correlations of clinical, neuroimaging, and electrophysiological features in Hirayama disease

Hirayama disease (HD) is characterized by development of asymmetric forearm muscle atrophy during adolescence with or without focal cervical spinal cord atrophy. The purpose of this study is to assess the correlation of clinical symptoms, disease progression, and electrophysiological findings with cervical spine magnetic resonance imaging (MRI) findings.The medical records, cervical spine MRIs, and electrophysiological findings of 44 HD patients were retrospectively reviewed and analyzed.Denervation changes in any single C5 to C7 root-innervated muscle (deltoid, biceps, triceps, or extensor digitorum communis) occurred more frequently in the 25 patients with cord atrophy than the 19 patients without cord atrophy (88% vs 53%, P = 0.02). Onset age, duration of disease progression, neurological examinations, nerve conduction study, and electromyographic findings from individual muscles were similar between patient groups.Compared with HD patients without cord atrophy, HD patients with cord atrophy experience a more severe denervation change in C5 to C7 root-innervated muscles.

The Quantitative Assessment of Imaging Features for the Study of Hirayama Disease Progression

Objective. To evaluate the forward shifting of cervical spinal cords in different segments of patients with Hirayama disease to determine whether the disease is self-limiting. Methods. This study was performed on 11 healthy subjects and 64 patients. According to the duration, the patients were divided into 5 groups (≤1 year, 1-2 years, 2-3 years, 3-4 years, and ≥4 years). Cervical magnetic resonance imaging (MRI) of flexion and conventional position was performed. The distances between the posterior edge of the spinal cord and the cervical spinal canal (X), the anterior and posterior wall of the cervical spinal canal (Y), and the anterior-posterior (A) and the transverse diameter (B) of spinal cord cross sections were measured at different cervical spinal segments (C4 to T1). Results. In cervical flexion position, a significant increase in X/Y of C4-5 segments was found in groups 2–5, the C5-6 and C6-7 segments in groups 1–5, and the C7-T1 segments in group 5 (P < 0.05). The degree of the increased X/Y and cervical flexion X/Y of C5-6 segments were different among the 5 groups (P < 0.05), which was likely due to rapid increases in X/Y during the course of Hirayama's disease. Conclusion. The X/Y change progression indicates that Hirayama disease may not be self-limiting.

Severe Spinal Injury in Hirayama Disease

Hirayama disease is a rare neurological disorder characterized by an insidious progressive subacute unilateral or bilateral weakness of the hands and forearm muscles leading to a painless amyotrophy. The disease primarily affects young men in the second to third decades of life. It has always been described as a second motor neuron disease, thus sparing the pyramidal and sensitive pathways. It usually has a slow progression course of 3 to 5 years followed by stabilization. Since its initial description by Keyzo Hirayama in 1959, most cases have been reported in Asia, particularly Japan and India, although the disease reportedly has worldwide distribution.

Monomelic amyotrophy: clinical profile and natural history of 279 cases seen over 35 years (1976-2010)

Our objective was to study the clinical characteristics and natural history of monomelic amyotrophy (MMA). We used a retrospective study of 279 patients diagnosed to have either upper (Hirayama disease) or lower limb MMA. Results showed that brachial MMA (BMMA) occurred in 224 patients (male:female, 9:1). Mean age of onset was 19.5 ± 4.18 years. Progression occurred over less than five years in the majority (95.9%) of patients. Duration at the last follow-up was: up to five years in 61.4%, 5-10 in 21.3%, 10-15 in 7.2%, > 15 years in 10.1%. MRI showed asymmetrical lower cervical cord atrophy in 44.6% of patients. Crural MMA (CMMA) occurred in 55 patients (male:female, 13:1). Mean age of onset was 21.38 ± 5.3 years. Similar to BMMA, most cases (65.5%) had onset between 15 and 25 years of age. Total duration of illness at the last follow-up was up to five years in 52.7%, 10 and beyond in 47.3%. In conclusion, a large cohort of patients with monomelic amyotrophy seen over 35 years (1976-2010) is described. Study data support the clinical findings and its natural history with long term follow-up, and the findings emphasize that monomelic amyotrophy is a 'benign' condition with a self-limiting course.

Hirayama disease in children from mainland of China

Hirayama disease is characterized by asymmetrical focal weakness and atrophy of the distal upper limbs with onset in the teens and early 20s. This retrospective study aims to review clinical features of the children (onset before the age of 18 years) with Hirayama disease from mainland of China. Sixty-five children who fulfilled the clinical criteria for Hirayama disease were enrolled. The mean age of onset was 15.7 years, 3.3 years later than the peak age for the normal growth curve. Electrophysiology studies showed chronic denervation changes in C7-T1 segments with normal sensory nerve conduction. Flexion cervical magnetic resonance imaging (MRI) showed forward shifting of the posterior dural sac and engorgement of the posterior epidural venous plexus. Therapeutic intervention with cervical collar can induce a premature arrest of disease progression. Knowledge and awareness of Hirayama disease will facilitate diagnosis and therapeutic intervention in its early stages.

Efficacy of anterior cervical decompression and fusion procedures for monomelic amyotrophy treatment: a prospective randomized controlled trial

Object

Monomelic amyotrophy (MMA) is a benign, self-limiting lower motor neuron disease. Optimal surgical strategies—discectomy decompression and fusion (DDF) or corpectomy decompression and fusion (CDF)—for patients with aggravated symptoms (within 6 months of presentation) are controversial, particularly in those who are ineligible for conventional treatment. These 2 methods of anterior cervical decompression and fusion for MMA in patients unwilling or unable to wear a conventional cervical collar long term were evaluated.

Methods

Anterior cervical decompression and fusion were performed in 48 male patients with MMA between September 2007 and September 2010. Patients were randomly treated with anterior cervical discectomy decompression with autologous iliac crest bone grafting and internal plate fixation (DDF group: 24 patients) or anterior cervical corpectomy, posterior longitudinal ligament resection, autologous iliac crest bone grafting, and internal plate fixation (CDF group: 24 patients). Subjective symptom assessments and electromyography (EMG) examinations were conducted both preoperatively and postoperatively.

Results

Subjective assessments and EMG studies (mean follow-up duration 25.9 months) indicated improvement in 64.6% and 60% of patients, respectively. No significant correlations between the effectiveness of surgery and age at symptom onset, preoperative symptom duration, or postoperative follow-up time were found.

Conclusions

The lack of a significant difference in effectiveness between DDF and CDF favors DDF as more clinically applicable because of its lower procedural risks. As a second-line alternative to cervical collar treatment, surgical anterior cervical decompression and fusion via DDF or CDF may prevent further deterioration and produce good short-term therapeutic effects in patients with MMA; however, cervical collar treatment is recommended for eligible patients because of its lower associated risks.

Hirayama disease: a frequently undiagnosed condition with simple inexpensive treatment

Hirayama disease is a non-progressive asymmetric juvenile muscular atrophy involving C7-T1 myotomes leading to weakness and atrophy of intrinsic muscles of hand and forearm with relative sparing of the brachioradialis muscle. This benign focal cervical poliopathy is believed to be caused by forward displacement of the posterior cervical dural sac. In this case report we highlight the importance of dynamic MRI of cervical spine for diagnosis of the above condition and the use of hard cervical collar to prevent further flexion injury.

A 20-year-old female with Hirayama disease complicated with dysplasia of the cervical vertebrae and degeneration of intervertebral discs

A 20-year-old female patient was presented with a 1-year history of progressive weakness of the left hand. Examination on admission showed atrophy of the muscles of the left forearm, cold paralysis and minipolymyoclonus. MR images of the cervical cord showed anterior transfer of the cervical cord on anterior flexion and cervical cord compression at the site of cervical kyphosis, confirming the diagnosis of Hirayama disease. Many features of the present case are unusual: the patient is a female (who are rarely afflicted by this disease), with cervical kyphosis and a history of exercise involving cervical vertebral loading, suggesting a potential involvement of the latter two factors in the disease onset. The findings suggest that cervical vertebral dysplasia and intervertebral disc degeneration may influence cervical kyphosis, and be involved in the onset of Hirayama disease.

A case of monomelic amyotrophy of the upper limb: MRI findings and the implication on its pathogenesis

Monomelic amyotrophy of the upper limb or Hirayama disease is mostly considered as an anterior horn disorder resulting from local ischemia, triggered by arterial compression from an anterior shifting of the posterior cervical dura upon neck flexion. However, such a dural shifting is not universally seen. We report on a Caucasian male patient who developed a slowly progressive unilateral distal hand weakness in his teens. His clinical and electromyographic findings were consistent with Hirayama disease. Local anterior cervical cord atrophy was observed without dural shifting on the dynamic magnetic resonance imaging. Axial magnetic resonance imaging demonstrated signal changes of "snake-eye" appearance in the cervical anterior horn region, similar to ischemic myelopathies caused by various etiologies. This case illustrated that even without dural shifting, a mechanism of anterior spinal cord ischemia could still be responsible for the pathogenesis of Hirayama disease.

Hirayama disease

Hirayama disease (juvenile muscular atrophy of distal upper extremity) is a cervical myelopathy. Predominantly affecting male adolescents, it is characterized by progressive muscular weakness and atrophy of distal upper limbs, followed by spontaneous arrest within several years. Although the cause of cervical myelopathy remains unclear, neuropathologic and neuroradiologic findings suggest a forward displacement of the posterior cervical dural sac during neck flexion, causing compression of the cervical cord, and results in atrophic and ischemic changes in the anterior horn. A good understanding of Hirayama disease is essential because early recognition and management can effectively halt the progressive deterioration.