Focal cervical poliopathy causing juvenile muscular atrophy of distal upper extremity: a pathological study

Sensory Dysfunction in ALS and Other Motor Neuron Diseases: Clinical Relevance, Histopathology, Neurophysiology, and Insights from Neuroimaging

Background: The clinical profiles of MNDs are dominated by inexorable motor decline, but subclinical proprioceptive, nociceptive and somatosensory deficits may also exacerbate mobility, dexterity, and bulbar function. While extra-motor pathology and frontotemporal involvement are widely recognised in motor neuron diseases (MNDs), reports of sensory involvement are conflicting. The potential contribution of sensory deficits to clinical disability is not firmly established and the spectrum of sensory manifestations is poorly characterised. Methods: A systematic review was conducted to examine the clinical, neuroimaging, electrophysiology and neuropathology evidence for sensory dysfunction in MND phenotypes. Results: In ALS, paraesthesia, pain, proprioceptive deficits and taste alterations are sporadically reported and there is also compelling electrophysiological, histological and imaging evidence of sensory network alterations. Gait impairment, impaired dexterity, and poor balance in ALS are likely to be multifactorial, with extrapyramidal, cerebellar, proprioceptive and vestibular deficits at play. Human imaging studies and animal models also confirm dorsal column-medial lemniscus pathway involvement as part of the disease process. Sensory symptoms are relatively common in spinal and bulbar muscular atrophy (SBMA) and Hereditary Spastic Paraplegia (HSP), but are inconsistently reported in primary lateral sclerosis (PLS) and in post-poliomyelitis syndrome (PPS). Conclusions: Establishing the prevalence and nature of sensory dysfunction across the spectrum of MNDs has a dual clinical and academic relevance. From a clinical perspective, subtle sensory deficits are likely to impact the disability profile and care needs of patients with MND. From an academic standpoint, sensory networks may be ideally suited to evaluate propagation patterns and the involvement of subcortical grey matter structures. Our review suggests that sensory dysfunction is an important albeit under-recognised facet of MND.

Clinical, Electrodiagnostic, Sonographic, and Radiological Findings of Hirayama Disease: A Report of Two Cases and a Review of the Literature

Hirayama disease (HD) is a rare disorder characterized by insidious asymmetric neurogenic atrophy primarily involving the upper extremities. HD most commonly affects adolescent males and has a favorable prognosis for arrest of progression. Electrodiagnostic (EDX) studies show chronic denervation changes in the distal upper extremity muscles. A cervical spine MRI in neck flexion may reveal compression of the cervical ventral spinal cord. We report clinical, EDX, and MRI findings in two cases of HD. The first case involved a 15-year-old male with a six-month history of progressive weakness, wasting, and tremulous movements of the left hand without pain or paresthesia. A physical exam revealed marked wasting of the left intrinsic hand muscles with polyminimyoclonus. Needle electromyography (EMG) revealed fasciculations (simultaneous with the polyminimyoclonus) while at rest and recruitment of 1-2 large polyphasic units in the left C8, T1, and, to a lesser extent, the C7 distribution. A T2-weighted flexion cervical spine MRI revealed narrowing and anterior displacement of the posterior dura of the cervical cord, leading to cord compression at C5-6 and C6-7. At last contact 11 years following symptom initiation, the patient continued to complain of profound weakness of the left hand without pain or numbness. The second case involved a 17-year-old male who was found to have wasting of the intrinsic muscles of the non-dominant left hand on a routine physical examination. The left first dorsal interosseus, abductor digiti minimi, abductor pollicis brevis, and extensor pollicis longus muscles were found to be clinically weak. Polyminimyoclonus involving all fingers of the left hand was also observed. A needle EMG demonstrated fasciculations with large amplitudes and wide duration motor unit potentials in the left C8, T1, and, to a lesser extent, C7 distribution. An ultrasound study showed frequent fasciculations in the left intrinsic hand muscles and the distal forearm muscles simultaneously with the polyminimyoclonus. A T2-weighted cervical spine MRI scan in the flexed sagittal position revealed anterior displacement of the dura and an enlarged epidural space from C4-C7. At last follow-up 11 months later, the findings were unchanged. The EDX studies and cervical MRI findings were consistent with HD in both cases. The role of EDX studies and cervical spine flexion MRI in diagnosing HD and the correlation between polyminimyoclonus and fasciculations are highlighted.

A Case Report and Review of Literature on Hirayama Disease

Hirayama disease (HD) is a rare, benign, self-limiting condition that typically affects individuals in their 20s. Although the disease is self-limiting, it can result in functional impairment in those affected. The most common presentation is an asymmetrical, unilateral, or bilateral upper limb weakness with wasting. With an interesting pathogenesis and lack of definitive treatment, HD is an interesting neurological conundrum. Mild symptoms in patients often lead to underreporting of the disease, as individuals may not seek medical attention or may not recognize their symptoms. Most case reports in the literature are from Asia and the Middle East. We report a case of HD in a male patient in his 20s with gradual bilateral upper limb weakness and wasting, confirmed by imaging and nerve conduction studies.

Long term quality of life follow-up and functional impairment study in patients with Hirayama disease

Hirayama Disease (HD) is a focal motor neuron disorder generally affecting young adults with a male predominance who experience weakness and atrophy in distal upper extremity muscles in an asymmetric or unilateral pattern. Progression is insidious though significant weakness occurs during a progressive phase of the disease over 2-5 years. The long-term outcome of HD is not as well-known and, thus, this study presents self-reported outcomes from HD patients years after a diagnosis. Thirty HD patients reported quality of life (QOL) and other functional outcome measures after a mean of just over 11 years from diagnosis. Variables that predicted better or worse outcome were analyzed. Overall, QOL was affected by HD though most patients were functional with limitations. No clear attributes of patients or their disease predicted outcome.

Monomelic Amyotrophy/Hirayama Disease: Surgical Outcome in a Large Cohort of Indian Patients

BACKGROUND

Hirayama disease (HD) is a cervical compressive myelopathy. Anterior cervical discectomy and fusion (ACDF) is identified as the best surgical approach. We evaluated surgical outcomes and factors influencing ACDF in HD.

METHODS

Between 2015 and 2019, 126 patients with HD underwent ACDF. Contrast magnetic resonance imaging of the cervical spine in full flexion was performed. Clinical examination and preoperative/postoperative assessment of hand function using Fugl-Meyer assessment, Jebsen-Taylor hand function test, and handheld dynamometry were performed at 3-monthly intervals for 1 year. Surgical outcomes were assessed as per the Odom criteria and Hirayama outcome questionnaire.

RESULTS

Age at onset and duration of illness were 12-31 years (mean, 18 ± 2.7) and 1-96 months (32.7 ± 24.4), respectively. All patients had progressive weakness and wasting of the affected limb. Cord atrophy was seen in 97.1%, with epidural detachment and engorgement of the posterior epidural venous plexus in all. All patients underwent ACDF. Of these patients, 54% had an excellent/good outcome and 39% had a satisfactory outcome as per the Odom scale at last follow-up (mean, 44.9 ± 16.5 months) after surgery. Handheld dynamometry showed improvement from preoperative values to 1 year follow-up. Duration of illness and age at onset had a negative correlation and the preoperative Fugl-Meyer score had a positive correlation with improvement.

CONCLUSIONS

ACDF resulted in remarkable improvement or stabilization in neurologic deficits in many patients with HD. Because motor disability ensues over time, early surgical intervention during the progressive phase is advocated.

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.

Anesthetic challenges in a patient with Hirayama disease with quadriparesis and autonomic dysfunction undergoing cervical spine surgery

Hirayama disease is a rare neurological disorder, characterized by muscular atrophy of the distal upper extremities. The occurrence of spastic quadriparesis and autonomic dysfunction is rarely reported and has important perioperative considerations during cervical spine surgery for the treatment of this disorder. The role of the anesthesiologist is vital in the thorough assessment of the patient for the involvement of the pyramidal tract, autonomic dysfunction, gastroparesis, hyperreactive airway disease, and documentation of neurological deficits. Intraoperative concerns include safe manipulation of the airway during mask ventilation and the use of a flexible fibreoptic bronchoscope during endotracheal intubation to prevent neck flexion. It is also essential to avoid drugs, leading to histamine release. The use of multimodal monitoring including bispectral index and neuromuscular monitoring is crucial to prevent delayed recovery. Anticipation and management of exaggerated hypotension in response to anesthetic induction agents and prone position is the key to a successful outcome in patients with autonomic dysfunction.

Venous pathology targeted surgical management in Hirayama disease: A comprehensive case series of nine cases exploring this potential etiology

Objective

Hirayama disease is a rare cause of cervical myelopathy predominantly affecting young individuals. The disease is classically characterized by muscle atrophy in the distal upper limbs. While various etiopathogenesis such as dural sac dysplasia, nerve root dysplasia, structural abnormalities of the spinal ligament, and venous dysplasia have been proposed, this study explores the potential role of venous pathology and surgical management on the basis of it.

Methodology

This is a prospective descriptive case series of nine cases. The diagnosis was made based on the Huashan diagnostic criteria which includes clinical manifestation, imaging, and electrophysiology. In cases where magnetic resonance imaging (MRI) failed to demonstrate engorged veins, a computed tomography (CT) venogram of the cervical spine was used as an imaging tool. All patients underwent cervical laminectomy and coagulation of the posterior epidural venous plexus with or without laminoplasty. All the patients were followed up regularly; clinical improvement and neck disability index were assessed.

Results

All nine patients were male and exhibited classical clinical features, electrophysiological abnormalities, and MRI findings except, in one patient where a CT venogram helped in establishing the diagnosis as the MRI was inconclusive. Postoperatively, all patients had neurological improvement and stabilization of the disease. All patients who underwent CT venogram and cervical spine X-ray in neutral and dynamic position demonstrated no recurrence of engorged venous plexus or significant instability except one patient developing kyphosis. One patient experiencing symptoms in the other limb underwent a second surgery.

Conclusion

This comprehensive case series strongly supports venous pathology as a potential etiology of Hirayama disease. Surgical management with laminectomy and venous coagulation with or without expansile laminoplasty has delivered consistent improvement in neurological outcomes and long-term disease stabilization without the restriction of movements and lesser complications. However, further research is warranted to elucidate the mechanism underlying cervical venous dilatation.

Diagnosis and differential diagnosis of MND/ALS: IFCN handbook chapter

•Accurate and rapid diagnosis of amyotrophic lateral sclerosis (ALS) is important to prevent erroneous interventions. •The recent Gold Coast criteria are easily applicable and have high sensitivity and specificity. •Future developments will help to distinguish ALS as a specific clinical-pathologic entity.

Accurate and rapid diagnosis of amyotrophic lateral sclerosis (ALS) is essential in order to provide accurate information for patient and family, to avoid time-consuming investigations and to permit an appropriate management plan. ALS is variable regarding presentation, disease progression, genetic profile and patient reaction to the diagnosis. It is obviously important to exclude treatable conditions but, in most patients, for experienced neurologists the diagnosis is clear-cut, depending on the presence of progressive upper and lower motor neuron signs. Patients with signs of restricted lower motor neuron (LMN) or upper motor neuron (UMN) dysfunction may present diagnostic difficulty, but electromyography (EMG) is often a determinant diagnostic test since it may exclude other disorders. Transcranial magnetic stimulation may aid detection of UMN dysfunction, and brain and spinal cord MRI, ultrasound and blood neurofilament measurements, have begun to have clinical impact, although none are themselves diagnostic tests. Several sets of diagnostic criteria have been proposed in the past; all rely on clinical LMN and UMN signs in different anatomic territories, EMG changes, exclusion of other disorders, and disease progression, in particular evidence of spreading to other anatomic territories. Fasciculations are a characteristic clinical feature and increased importance is now attached to fasciculation potentials detected by EMG, when associated with classical signs of denervation and reinnervation. The Gold Coast diagnostic criteria rely on the presence of UMN and LMN signs in one (or more) anatomic territory, or LMN signs in two (or more) anatomic territories, recognizing the fundamental clinical requirements of disease progression and exclusion of other diseases. Recent studies confirm a high sensitivity without loss of specificity using these Gold Coast criteria. In considering the diagnosis of ALS a critical question for future understanding is whether ALS should be considered a syndrome or a specific clinico-pathologic entity; this can only be addressed in the light of more complete knowledge.

The role of leisure-time physical activity in maintaining cervical lordosis after anterior cervical fusion and its impact on the motor function in patients with hirayama disease: a retrospective cohort analysis

BACKGROUND

Surgical treatment has been increasingly performed in Hirayama disease (HD) patients to limit excessive neck flexion and restore cervical lordosis. However, postoperative recurrence of cervical lordosis loss may restart the progress of HD. Many studies have demonstrated a relationship between neck muscle strength and cervical lordosis, and it is widely accepted that leisure-time physical activity (LTPA) can increase muscle strength. However, there are few reports about the correlation between LTPA and maintenance of postoperative cervical curvature.

OBJECTIVE

To quantify the cervical lordosis and motor function before and after operation in HD patients and to analyze the impact of postoperative LTPA levels on the changes in these measurements.

METHODS

C2-7 Cobb were measured in 91 HD patients before, 2-5 days and approximately 2 years after operation. Motor unit number estimation (MUNE) and handgrip strength (HGS) were performed in all patients before and approximately 2 years after operation, and both cross-sectional area and fatty infiltration of posterior cervical muscles were measured in 62 patients. Long-form international Physical Activity Questionnaire and its different domains was administered to all patients at postoperative 2-year assessments.

RESULTS

The C2-7 Cobb was larger immediately and approximately 2 years after operation than that at preoperative assessment (P < 0.05). The preoperative to postoperative change in C2-7 Cobb was associated with postoperative changes in the symptomatic-side HGS and bilateral MUNE measurements (P < 0.05). Importantly, the patients performing LTPA had greater improvements in C2-7 Cobb from immediate to approximately 2 years after operation and greater C2-7 Cobb at last follow-up than those without LTPA, and postoperative improvements in both symptomatic-side MUNE measurements and symptomatic-side HGS were also greater in the former than in the latter (P < 0.05).

CONCLUSIONS

Postoperative LTPA has a positive effect on recovery/maintenance of cervical lordosis after operation, which may alleviate the motor unit loss of distal upper limbs in HD patients. Therefore, postoperative LTPA may be beneficial for postoperative rehabilitation or early conservative treatment of HD patients.

Association of joint hypermobility with range of cervical motion and its impact on the motor unit loss in patients with Hirayama disease

INTRODUCTION/AIMS

Some patients with Hirayama disease (HD) may have generalized joint hypermobility (GJH), which may excessively increase cervical range of motion (ROM) and then worsen the HD. The purpose of this study was to identify the frequency of GJH in HD patients and to analyze the effect of GJH on cervical ROM and the severity of HD.

METHODS

The Beighton scoring system (≥4) was used to diagnose GJH in 84 HD patients. All patients underwent assessments of cervical-flexion/extension ROM; motor unit number estimation in bilateral abductor pollicis brevis (APB) muscles; handgrip strength; and the disabilities of the arm, shoulder, and hand assessments.

RESULTS

Concomitant GJH was identified in 20 (23.8%) HD patients. The HD patients with GJH exhibited greater cervical-flexion (P < .001) and cervical-extension (P = .033) ROM than those without GJH. Both greater single motor unit potential amplitudes (symptomatic side: P = .005; less-symptomatic side: P = .011) and lower motor unit numbers (symptomatic side: P = .008; less-symptomatic side: P = .013) in bilateral APB, along with lower compound muscle action potential amplitudes on the symptomatic-side APB (P = .039), were observed in patients with GJH than those without GJH. There was a mild negative correlation between motor unit number and cervical-flexion ROM in HD patients (symptomatic side: r = -0.239, P = .028; less-symptomatic side: r = -0.242, P = .027).

DISCUSSION

The frequency of GJH in HD patients may be higher than in the general population. Importantly, GJH may exacerbate excessive cervical-flexion ROM, thereby worsening motor unit loss in HD patients. A cautious approach should be taken when treating HD due to possible comorbid GJH.

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.

Severe cervical kyphosis in a young adult with fixed dropped head syndrome, dysphagia, and myelopathy: A case report

BACKGROUND

Several reports exist on syndromic cervical kyphosis in the elderly, including dropped head syndrome, degenerative spondylosis, and neurological diseases; however, it is rarely reported in young patients especially with complications.

CASE PRESENTATION

We describe a case of a 25-year-old man who presented severe cervical kyphosis with dropped head syndrome, horizontal-gaze disorder, dysphagia, and myelopathy. The etiology of this cervical kyphosis was suspected to be as a result of a combination of an underlying developmental disorder and habitual, long-term cervical flexion postures while engaging in smartphone games. Combined anterior and posterior surgeries resulted in good outcomes and improved the patient's quality of life remarkably.

CONCLUSION

Cervical kyphosis awareness in young patients is crucial. Moreover, combined anterior and posterior approach provides secure, good results, and with less sequelae.

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.

Loss of cervical sagittal alignment worsens the cervical spinal lesions in patients with Hirayama disease

OBJECTIVE

To quantify the cervical sagittal alignment in patients with Hirayama disease (HD) and to investigate the effect of loss of cervical sagittal alignment upon the cervical spinal lesions in HD.

METHODS

Cervical sagittal alignments were measured in 253 HD patients and 63 healthy subjects by C2-C7 Cobb and a modified method of Toyama et al. Motor unit number estimation (MUNE) was performed in bilateral abductor pollicis brevis (APB) in all HD patients, and 31 patients further underwent cervical diffusion tensor imaging (DTI).

RESULTS

Compared with healthy subjects, HD patients showed lower C2-C7 Cobb (P < 0.05), and 83.4% patients showed loss of cervical lordosis (cervical straight or kyphosis), which was greater than healthy subjects (55.6%, P < 0.05). Compared with lordotic/straight group, patients with cervical kyphosis showed lower MUNE values and greater single motor unit potential (SMUP) in bilateral APB, and higher apparent dispersion coefficient (ADC) and lower fractional anisotropy were observed at C4/C5 level in the latter than the former (P < 0.05). C2-C7 Cobb was associated with both C4/C5 ADC and bilateral SMUP (P < 0.05).

CONCLUSIONS

Most HD patients showed loss of cervical sagittal alignments, and both MUNE and DTI detections demonstrated a positive correlation between loss of cervical sagittal alignments and cervical spinal lesions in HD. These findings supported that loss of cervical sagittal alignments may worsen motor impairments in HD. Therefore, it is necessary for clinicians to be aware of restoring cervical sagittal alignments during HD treatment.

[Monomelic amyotrophy]

Monomelic amyotrophy, also known as Hirayama disease, is a rare neurological disorder characterized by focal and latent onset of upper limb weakness and atrophy in the absence of sensory deficits, bulbar or pyramidal signs. It usually occurs in young patients. The disease usually begins unnoticeably and progresses slowly, and can manifest itself as unilateral or asymmetrical weakness, as well as atrophy of the distal upper limb. Sensory disturbances, reflex changes and signs of lesions of lower motor neurons are rare. This article describes a case of a patient with complaints of weakness not only in the upper but also in the lower extremities.

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.

Hirayama disease: Nosological classification and neuroimaging clues for diagnosis

Hirayama disease (HD) is a rare, benign, and nonprogressive motor neuron disease (MND) affecting the upper limbs. It usually presents with weakness and amyotrophy in a single upper extremity with an insidious onset between adolescence and the third decade of life. Since its description in 1959, HD has been known under several names and eponyms in Europe and in Asian countries probably due to its heterogeneous clinical features. Thus, the unclear nosological classification makes challenging the differential diagnosis between HD and other neuromuscular conditions, such as MNDs. However, apart from the nosological difficulties and the lack of evidence‐based guideline for diagnosis, the neuroimaging is the mainstay for the diagnosis of HD. Indeed, the specific findings on cervical flexion MRI usually lead to a prompt diagnosis. Here, we reviewed the nosological classifications of HD and its neuroimaging features. Also, we report a case of a 18‐year‐old boy who presented to our Clinic complaining of muscle weakness of the left distal upper limb without other neurological signs. The cervical MRI, in the neutral position, revealed a high T2 signal intensity in the C5‐C7 cervical myelomeres as well as the loss of cervical lordosis, whereas, during neck flexion, it showed the anterior displacement of the posterior dura ad the post‐gadolinium T1‐weighted imaging enhancement of the posterior epidural plexus. These findings are typical for HD allowing the diagnosis as well as the differential diagnosis from other neuromuscular diseases.

Cervical Flexor–Extensor Muscle Disparity in Monomelic Amyotrophy (Hirayama Disease): Evidence from a Comprehensive Morphometric Evaluation of Subaxial Paraspinal Musculature

Background  Monomelic amyotrophy (Hirayama disease) has been established to have accompanied biomechanical abnormalities such as flexion hypermobility and sagittal imbalance. Paraspinal muscles, the major contributor to cervical biomechanics, have, however, not been comprehensively evaluated in the disease. The objective of this study was to compare the morphology of the subaxial cervical paraspinal musculature in patients with and without Hirayama disease.

Materials and Methods  A retrospective case-control study of 64 patients with Hirayama disease and 64 age- and sex-matched controls was performed . Cross-sectional areas (CSAs) of the superficial and deep flexors and extensors from C3 to C7 were measured on T2-weighted magnetic resonance imaging sequences. Student's t -test was used to compare differences between the paraspinal muscle CSAs in the study and control groups.

Results  Compared with controls, patients with Hirayama disease were found to have larger flexors and smaller extensors at all levels. The overall subaxial muscle area values for superficial flexors and deep flexors were significantly larger ( p  < 0.0001) in patients, while the corresponding superficial extensor and deep extensor area values were significantly smaller than in controls ( p  = 0.01 and < 0.0001, respectively). The patient group demonstrated stronger subaxial deep flexor–deep extensor, superficial flexor–superficial extensor, and total flexor–total extensor ratios ( p  < 0.0001).

Conclusion  Patients with Hirayama disease have morphometric alterations at all levels of their subaxial cervical paraspinal musculature. These patients have abnormally large flexors and small extensors compared with controls. This flexor–extensor muscle disparity could be utilized as a potentially modifiable factor in the management of the disease.

Update on the Pathogenesis, Clinical Diagnosis, and Treatment of Hirayama Disease

Hirayama disease (HD) is characterized by the juvenile onset of unilateral or asymmetric weakness and amyotrophy of the hand and ulnar forearm and is most common in males in Asia. A perception of compliance with previous standards of diagnosis and treatment appears to be challenged, so the review is to update on HD. First, based on existing theory, the factors related to HD includes, (1) cervical cord compression during cervical flexion, (2) immunological factors, and (3) other musculoskeletal dynamic factors. Then, we review the clinical manifestations: typically, (1) distal weakness and wasting in one or both upper extremities, (2) insidious onset and initial progression for 3-5 years, (3) coarse tremors in the fingers, (4) cold paralysis, and (5) absence of objective sensory loss; and atypically, (1) positive pyramidal signs, (2) atrophy of the muscles of the proximal upper extremity, (3) long progression, and (4) sensory deficits. Next, updated manifestations of imaging are reviewed, (1) asymmetric spinal cord flattening, and localized lower cervical spinal cord atrophy, (2) loss of attachment between the posterior dural sac and the subjacent lamina, (3) forward displacement of the posterior wall of the cervical dural sac, (4) intramedullary high signal intensity in the anterior horn cells on T2-weighted imaging, and (5) straight alignment or kyphosis of cervical spine. Thus, the main manifestations of eletrophysiological examinations in HD include segmental neurogenic damages of anterior horn cells or anterior roots of the spinal nerve located in the lower cervical spinal cord, without disorder of the sensory nerves. In addition, definite HD needs three-dimensional diagnostic framework above, while probable HD needs to exclude other diseases via "clinical manifestations" and "electrophysiological examinations". Finally, the main purpose of treatment is to avoid neck flexion. Cervical collar is the first-line treatment for HD, while several surgical methods are available and have achieved satisfactory results. This review aimed to improve the awareness of HD in clinicians to enable early diagnosis and treatment, which will enable patients to achieve a better prognosis.

Outcomes after Cervical Duraplasty for Monomelic Amyotrophy (Hirayama Disease): Results of a Case-Control Study of 60 Patients

Background  The optimal management and the role of surgery in monomelic amyotrophy, also known as Hirayama disease (HD), remain controversial. In the largest series of patients with HD managed by cervical duraplasty (CD), this study compares the outcomes between conservative and surgical management. Methods  A retrospective case-control study was performed on 60 patients with HD. The cases consisted of 30 patients who underwent CD, and 30 age- and sex-matched controls who managed with long-term collar wear. Clinical improvement was recorded using two patient-reported outcome measures-the Odom's scale and a self-rated hand grip strength score. Median and ulnar compound muscle action potential (CMAP) amplitudes and various magnetic resonance imaging parameters were recorded. Results  None of the controls experienced clinical improvement at follow-up; 90% remained status quo at 24.33 ± 9.38 months. Seventy-six percent of the operated patients demonstrated clinical improvement at 29.61 ± 12.78 months, and a majority of them reported moderately better grip strength. The preoperative anteroposterior diameter (APD) of the surgical group improved from 0.74 ± 0.13 to 0.86 ± 0.21 ( p  = 0.01), and the cord demonstrated a significant decrease in forward migration on flexion (0.20 ± 0.11 and 0.03 ± 0.07 preoperatively and at follow-up, respectively, p  < 0.0001). Patients with clinical improvement demonstrated significantly better mean APD and median and ulnar CMAP values than those who did not improve ( p  < 0.0001). The mean cervical alignment did not change significantly at follow-up ( p  = 0.13). Conclusions  This study shows that CD can significantly alter the clinical course of patients with progressive symptoms of HD. This approach successfully arrests the forward migration of the cervical cord on flexion and promotes morphological recovery of the cord. A majority of the patients undergoing CD demonstrate clinical and electrophysiological improvement at mid-term follow-up.

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.

Cardiovascular and sudomotor dysfunction in Hirayama disease

Hirayama disease is a disease of young males causing atrophy of small muscles of the affected hand and forearm. Localized autonomic dysfunction of the affected upper limb such as cold skin and excessive sweating has been described in some patients. In this study, we looked for local as well as systemic involvement of autonomic nervous system in patients with Hirayama disease. Forty-four patients with a median duration of illness of 3 years were included in the study. Assessment of symptom profile and evaluation of autonomic nervous system were done at the time of enrolment. The mean age at presentation was 21.9 (10-32) years, with a delay in seeking medical attention of around 3 (1-11) years. Localized clinical autonomic dysfunction was present in 39 (88.6%) patients, while objective generalized autonomic dysfunction was present in 33 (75%) patients. Cold skin and excessive sweating showed good correlation with the presence of objective autonomic dysfunction (P < 0.05). In three patients, sympathetic skin response (SSR) could not be recorded in one of the four limbs. Compared to controls, the SSR results in patients with Hirayama disease showed increased latency (1.64 ± 0.21 vs. 1.57 ± 0.14, P 0.04) and decreased amplitude in upper limbs (0.65 ± 0.19 vs. 0.86 ± 0.40, P 0.01). Hirayama disease has both localized and systemic dysautonomia. Careful longitudinal evaluation during the progressive phase of the disease may help in diagnosing subtle systemic autonomic dysfunction.

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.

Somatosensory evoked potentials in Hirayama disease: A Brazilian study

Background:

Hirayama’s disease (HD) is characterized by an insidious onset asymmetric weakness and atrophy of the forearm and hand. Taking as a premise, the etiopathogenesis of the disease is attributed to forward displacement of posterior wall of lower cervical dural canal in neck flexion causing marked compression and flattening of lower spinal cord. This may result in compression of the posterior column of the spinal cord and seems likely to result in somatosensory evoked potentials (SSEPs) abnormalities. In the present study, we studied the possible involvement of the lemniscal dorsal pathway in patients with HD.

Methods:

SSEPs in upper and lower extremities were prospectively performed in eight patients with HD. All the patients were recruited from the outpatient clinic of a neuromuscular disorder center from South Brazil. SSEPs were obtained by transcutaneous electrical stimulation of the median and posterior tibial nerves, on both sides. We collected the amplitude and the latency of the different components obtained in each channel. The interpretation was based on Brazilian study standards.

Results:

We evaluated seven men and one woman (mean age 27). The data obtained were compared to a control group consisting of eight patients with spondylotic cervical myelopathy, 6 men and 2 women with mean age of 59 years. The measurements of obtained by the SSEP were also compared between the groups and no significant difference was found for any of them.

Conclusion:

SSEP did not turn out to be an electrophysiological marker in our HD patients.

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.].

An Interesting Case of Bilateral Upper Limb Wasting: Hirayama Disease

Hirayama disease is a rare neurologic disease and is characterized by insidious unilateral or bilateral muscular atrophy and weakness of the forearms and hands without sensory or pyramidal signs. Our patient presented with bilateral upper limb wasting, which is a rarer variant of motor neuron disease. The diagnosis of Hirayama disease is based on dynamic magnetic resonance imaging (MRI). This case displays how dynamic cervical spine MRI can pick up dynamic cord compression and contributes to zero in the diagnosis of Hirayama disease.

Hirayama Disease Presenting as 4-Limb Paresthesia

INTRODUCTION

Hirayama disease is a rare clinical entity that presents typically as a unilateral, slowly progressive arms weakness, mostly occurring in young men.

CASE REPORT

We report a case of Hirayama disease in a 20-year-old man presenting with a 4-year history of progressive paresthesia starting in his left arm, progressing to the right arm 1 year later. Four months before the presentation, he experienced bilateral foot paresthesias. Examination revealed weakness of the abductor digiti minimi, hallux extension weakness, and postural tremor bilaterally. He had hypersensitivity to pinprick in both hands with ulnar and median distribution. Sensory examination in the legs was normal. He had a postural tremor in both hands, which worsened on neck flexion. Spinal fluid analysis, including oligoclonal band testing, was normal. Electromyography demonstrated bilateral chronic C7 and C8 radiculopathies. Laboratory tests were normal. Flexion-extension magnetic resonance imaging demonstrated laxity of the dura and ligamentum flavum, with compression of cervical cord, maximal at C5-C6 in neck flexion.

CONCLUSIONS

Laxity of the posterior dura during neck flexion has been postulated to lead to asymmetric lower cervical cord atrophy. Involvement of all 4 limbs is rare, and the condition can be mistaken for progressive multiple sclerosis.

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.

Flexion MRI in a case of Hirayama disease

We report the case of an 18-year old male with a history of asymmetric weakness and amyotrophy of distal upper extremities, suggestive of Hirayama disease. Magnetic resonance imaging (MRI) of the cervical spine was obtained both in flexion and neutral position. Flexion MRI showed forward displacement of the dura and subsequent cord compression, with associated marked enlargement and postcontrast enhancement of posterior epidural plexus. These findings are pathognomonic of the disorder. On neutral MRI abnormalities may be subtle: in our case, they included loss of physiological lordosis, asymmetric atrophy and increased T2 signal intensity of the lower anterior cervical cord. The ability to identify abnormalities on neutral MRI however is even more important in that it allows the radiologist to include a flexion sequence in the MRI examination, if not specifically requested by the referring physician, and in cases in which the suspicion of the disorder has not been raised.

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.

Vietnamese Case Series of Hirayama Disease

BACKGROUND/AIM

Hirayama disease, a rare neurological disorder, is characterized by progressive, asymmetric muscle atrophy of the forearm and hand in young male patients.

CASE REPORT

We noted two cases of Hirayama disease that appeared in the right upper limb and identified the cervical neutral and flexion position magnetic resonance imaging (MRI) characteristics.

CONCLUSION

In the flexion posture, the cervical MRI allows early diagnosis of Hirayama disease and should be considered in patients with the typical clinical symptoms.

Hirayama Disease Treated by Anterior Cervical Diskectomy and Fusion: Case Report and Literature Review

OBJECTIVE

We present the case of a 19-year-old boy who had the classic radiologic and clinical presentations of Hirayama disease treated with anterior cervical diskectomy and fusion (ACDF). We also propose ACDF as promising surgery for the treatment of Hirayama disease. Hirayama disease is an initially progressive disease caused by cervical neck flexion compressing the anterior horns of the lower cervical spinal cord.

CASE DESCRIPTION

Our patient presented with an insidious, progressive weakness in his right hand, which had been ongoing for 1 year. Physical examination revealed various degrees of right forearm and hand muscle wasting, and decreased right hand extend power with motor grade Ш. Cervical flexed magnetic resonance imaging showed a spinal cord was being compressed-most noticeably at the level of the fifth cervical vertebral body-and that the dorsal epidural space was abnormally expanding. The patient underwent ACDF at the C4-6 level. The pain and paresthesia improved immediately after the surgery. His motor grade improved immediately after the operation, and there were improvements of a modest reversal of muscle wasting at 1 year postoperatively.

CONCLUSIONS

ACDF could be considered as an effective treatment option for the treatment of Hirayama disease. Our patient's finger function improved. Therefore we believe that anterior fusion might be the best choice of treatment.

Hirayama disease – Early MRI diagnosis of subacute medullary ischemia: A case report

Background:

Hirayama disease (HD) is a rare, benign, and self-limiting motor neuron disorder that results in selective motor impairment of the C7-T1 myotomes. It is characterized by progressive, unilateral, or bilateral asymmetric muscle atrophy of the distal upper extremities and myelopathy.

Case Description:

A 23-year-old male presented with bilateral atrophy of the thenar/hypothenar eminences/ interosseous muscles, plus left-hand weakness. The cervical MRI documented subacute ischemic damage of the distal cervical cord. To rule out a tumor and reduce questionable cord compression, the patient underwent a C5–C6 anterior cervical discectomy and fusion (ACDF) immediately followed by a laminectomy with durotomy and to obtain a spinal cord biopsy. When the histology confirmed focal cord ischemia consistent with HD, it was clear that both operations were unnecessary.

Conclusion:

Establishing the diagnosis of HD is based on clinical findings and MRI/flexion MR features which include the demonstration of an increased T2-weighted intramedullary cord signal, enlargement of the posterior epidural space, and segmental spinal cord atrophy. The presence of HD should be recognized as a “nonsurgical entity,” and conservative nonsurgical management should be employed.

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.

Transcranial Magnetic Stimulation-Induced Motor Evoked Potentials in Hirayama Disease: Systematic Review of the Literature

PURPOSE

Hirayama disease (HD) is a rare motor disorder mainly affecting young men, characterized by atrophy and unilateral weakness of forearm and hand muscles corresponding to a C7-T1 myotome distribution. The progression is self-limited. The etiology of HD is unclear. The usefulness of motor evoked potentials (MEPs) in pyramidal tracts damage evaluation still appears to be somehow equivocal.

METHODS

We searched PubMed for original articles, evaluating the use of transcranial magnetic stimulation elicited MEPs in HD using keywords "motor evoked potentials Hirayama" and "transcranial magnetic stimulation Hirayama."

RESULTS

We found seven articles using the above keywords that met inclusion criteria. The number of participants was small, and diagnostic procedures varied. There were also differences in methodology. Abnormal central motor conduction time was found in 17.1% of patients in one study, whereas it was normal in two other studies. Peripheral motor latency was evaluated in one study, which found abnormally increased peripheral motor latencies in at least one tested muscle in 16 of 41 HD patients (39.0%). Abnormal MEP parameters were found in three studies in 14.3% to 100% patients. In one study they were not evaluated, in three other studies they were normal, and in one they were normal also in standard and flexed neck position In one study, inconsistent results were found in MEP size after neck flexion in patients after treatment with neck collar.

CONCLUSIONS

Although MEP parameters may be abnormal in some HD patients, these have not been thoroughly assessed. Further studies are indispensable to evaluate their usefulness in assessing pyramidal tract damage in HD.

Hirayama's Disease in a Young Male: A Rare Case Report

Hirayama disease is a rare neurological condition also known as monomelic amyotrophy (MMA). It is a type of cervical myelopathy, which involves the anterior horn cells and affects the distal upper extremities. It is self-limited, asymmetrical lower motor weakness of hands and forearms. Young males are more commonly affected. The condition is hypothesized to occur due to an asymmetric compression of the cervical spinal cord by the dural sac, however, the exact mechanism(s) continue to be investigated. We report a case of a 20-year-old male who presented with complaints of right hand and forearm weakness, who was diagnosed with Hirayama disease and treated.

A role for spinal cord hypoxia in neurodegeneration

The vascular system of the spinal cord is particularly complex and vulnerable. Damage to the main vessels or alterations to the regulation of blood flow will result in a reduction or temporary cessation of blood supply. The resulting tissue hypoxia may be brief: acute, or long lasting: chronic. Damage to the vascular system of the spinal cord will develop after a traumatic event or as a result of pathology. Traumatic events such as road traffic accidents, serious falls and surgical procedures, including aortic cross-clamping, will lead to an immediate cessation of perfusion, the result of which may not be evident for several days, but may have long-term consequences including neurodegeneration. Pathological events such as arterial sclerosis, venous occlusion and spinal cord compression will result in a progressive reduction of blood flow, leading to chronic hypoxia. While in some situations the initial pathology is exclusively vascular, recent research in neurodegenerative disease has drawn attention to concomitant vascular anomalies in disorders, including amyotrophic lateral sclerosis, spinal muscular atrophy and muscular sclerosis. Understanding the role of, and tissue response to, chronic hypoxia is particularly important in these cases, where inherent neural damage exacerbates the vulnerability of the nervous system to stressors including hypoxia.

Are basketball players more likely to develop Hirayama disease?

Hirayama disease is a rare neurological disease affecting primarily men in the second to third decades. To date there are only few reports from Italy. We report the case of three young basketball players who presented with clinical, electrophysiological and MRI findings suggestive for Hirayama disease. Although the pathophysiology of the disease is still unknown, several hypotheses have been suggested and two of these are the disproportionate growth of cervical spine and cervical cord/roots during adolescence and the chronic traumatism. We think that, in our cases, the height of basketball players combined with the constant stress caused by the sport, could have contributed to the development of the Hirayama disease. With this report we would stress the importance to be careful to consider this pathology in order to avoid misdiagnosis predictive of poor prognosis in young patients.

Hirayama disease: analysis of cases in Russia

The fourteen cases of Hirayama disease (HD) are presented in this article. HD is seldom disease characterized by juvenile muscular atrophy of upper extremities and benign course. All cases were diagnosed in the Research Center of Neurology (Moscow, Russia) during the year 2015-2017. Such methods as MRI (magnetic resonance imaging), EMG (electromyography), and NCS (nerve conduction studies) have been used to confirm diagnosis of HD. Transcranial magnetic stimulation was used to exclude upper motor neuron involvement in two cases. The original scale of neurological disturbances in HD has been proposed by authors to reveal correlations of HD severity with age of patients and duration of disease.Most of patients with HD are young males with common clinical signs. Detected MRI and EMG data were also comparable with previous publications. Independence of HD severity from age and duration of the disease may be the result of individual physical characteristics of dura mater and other structures of the cervical vertebra. In some our cases, amyotrophic lateral sclerosis and other neurological disorders were misdiagnosed before. In view of different prognosis in these pathologies and possible correction of HD, early diagnosis is very important.

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.

Changes in the soleus H-reflex test and correlations between its results and dynamic magnetic resonance imaging abnormalities in patients with Hirayama disease

OBJECTIVE

To investigate changes in soleus H-reflex tests in patients with Hirayama disease (HD) and to analyse correlations between these changes and forward-shifting of the cervical cord during neck flexion.

METHODS

The amplitude of the soleus H-reflex with and without vibration on the Achilles tendon was recorded bilaterally in 81 HD patients and 34 controls to measure both the vibratory inhibition index (VII) and the H_max/M_max ratio. The maximum forward-shifting degree of cervical cord during neck flexion was measured using dynamic magnetic resonance imaging in all HD patients.

RESULTS

Significantly higher VII was recorded in 6/81 (7.4%) HD patients, along with abnormal H_max/M_max ratios in 5 of 6 cases. Compared to illness duration (r = 0.29-0.36, p < 0.05), the maximum forward-shifting degree of the cervical cord was more strongly correlated with both VII and the H_max/M_max ratio (r = 0.51-0.81, p < 0.05).

CONCLUSIONS

HD patients may develop cervical spinal cord injury with disease progression, and these lesions may be more likely to occur in cases with relatively severe cervical-flexion structural abnormalities even during early stages.

SIGNIFICANCE

More caution should be taken when managing HD patients with severe cervical-flexion abnormalities because of the possible early occurrence of upper motor neuron lesions.