Cortical Activation Changes in Hirayama Disease After Anterior Cervical Decompression and Fusion

Anterior cervical discectomy and fusion for the treatment of pediatric Hirayama disease

PURPOSE

Hirayama disease, a rare cervical myelopathy in children and young adults, leads to progressive upper limb weakness and muscle loss. Non-invasive external cervical orthosis has been shown to prevent further neurologic decline; however, this treatment modality has not been successful at restoring neurologic and motor function, especially in long standing cases with significant weakness. The pathophysiology remains not entirely understood, complicating standardized operative guidelines; however, some studies report favorable outcomes with internal fixation. We report a successful surgically treated case of pediatric Hirayama disease, supplemented by a systematic review and collation of reported cases in the literature.

METHODS

A review of the literature was performed by searching PubMed, Embase, and Web of Science. Full-length articles were included if they reported clinical data regarding the treatment of at least one patient with Hirayama disease and the neurologic outcome of that treatment. Articles were excluded if they did not provide information on treatment outcomes, were abstract-only publications, or were published in languages other than English.

RESULTS

Of the fifteen articles reviewed, 63 patients were described, with 59 undergoing surgery. This encompassed both anterior and posterior spinal procedures and 1 hand tendon transfer. Fifty-five patients, including one from our institution, showed improvement post-treatment. Eleven of these patients were under 18 years old.

CONCLUSION

Hirayama disease is an infrequent yet impactful cervical myelopathy with limited high-quality evidence available for optimal treatment. The current literature supports surgical decompression and stabilization as promising interventions. However, comprehensive research is crucial for evolving diagnosis and treatment paradigms.

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.

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.

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.

Surgical treatment of spinal cord compression due to Hirayama disease: illustrative case

BACKGROUND

Hirayama disease (HD), also known as juvenile spinal muscular atrophy, is a rare condition in which flexion of the cervical neck causes compression and ischemic changes to the anterior horns of the spinal cord. Here the authors presented the first reported case of HD in North America that was successfully treated via surgical intervention.

OBSERVATIONS

The patient was a 15-year boy with insidious onset upper limb weakness and atrophy. His findings were a classic presentation of HD although his complex history and relative rarity of the disease caused him to remain undiagnosed for months. After conservative management via cervical collar failed, the patient was successfully treated via C5-C7 anterior cervical discectomy and fusion. The patient’s symptoms stabilized by the 3-month follow-up.

LESSONS

The diagnosis of HD is easy to miss because of the lack of reporting and widespread knowledge of this condition in North America. Thus, when presented with a case of insidious onset limb weakness in a juvenile patient, HD should be placed on the differential list and verified with cervical flexion magnetic resonance imaging. Additionally, surgical intervention should be considered a safe and effective option for HD when conservative methods have failed.

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.

Why the patients with Hirayama disease have abnormal cervical sagittal alignment? A radiological measurement analysis of posterior cervical extensors

PURPOSE

To explore the relationship between the strength of posterior cervical extensors (PCEs) and cervical sagittal alignment in Hirayama disease (HD) patients.

METHODS

We analyzed the (magnetic resonance imaging) MRI T2WI and X-rays of 60 HD patients who visited Huashan Hospital from June 2017 to February 2020. Symptoms of these patients include adolescent onset, manifestation of unilateral upper limb muscle weakness and muscle atrophy of the forearm and hand. MRI images were used to measure (the cross-sectional area) CSA of cervical PCEs. The ratio of muscle CSA to vertebral body areas at the same level is defined as R-CSA. Cervical sagittal alignment includes the C_2-7 Cobb angle, T1 slope and C_2-7 sagittal vertical axis (SVA). The geometric center of the C_3-6 vertebral body was determined using the line connecting the C₂ inferior endplate and the C₇ upper endplate. When located behind the line, it is defined as a "local kyphotic deformity." The number of vertebral bodies involved in kyphotic deformity was determined by measuring the local kyphosis angle (LKA). Spearman correlation analysis (α = 0.05) was used to determine the relationship between R-CSA and sagittal parameters. ROC curves were used to analyze the sensitivity and specificity of relevant variables.

RESULTS

Spearman correlation test revealed that R-CSA negatively correlated with T1S (S = 0.34, r = 0.34, p = 0.01) and LKA (S = 0.44, r = 0.5, p = 0.01), but did not correlate with the C2-C7 Cobb angle (S = 0.20, p = 0.12) or C2-C7 SVA (S =  - 0.17, p = 0.46). (p < 0.05). ROC curve analysis showed that the areas under the curve (AUCs) of the T1 slope and LKA was 0.6696 and 0.7646, respectively. T1 slope, cutoff value: 17.2°; sensitivity: 0.5806; specificity: 0.7241; p < 0.05. LKA: cutoff value: - 14°; sensitivity: 1; specificity: 0.5333; p < 0.05.

CONCLUSIONS

In patients with Hirayama disease, the strength of posterior cervical extensors and cervical sagittal alignment are closely related. The local kyphosis angle can be used as a reference for the strength of posterior cervical extensors. These results indicate the weakness of PCEs, which may predispose the cervical spine of HD patients to a less stable situation. Therefore, patients with Hirayama disease should strengthen the exercise of the PCEs.

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.

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.

Analysis of the Effect of Surgical Treatment for the Patients with Hirayama Disease from the Perspective of Cervical Spine Sagittal Alignment

OBJECTIVE

This study was carried out to analyze the surgical effect of cervical spine sagittal alignment for patients with Hirayama disease (HD).

METHODS

Forty-four subjects were retrospectively analyzed for the parameters of cervical spine sagittal alignment. The case group consisted of 23 patients with HD, whereas the control group consisted of 21 healthy adolescent subjects. Pre- and postoperative cervical spine sagittal parameters of the patients with HD were collected; the cervical sagittal parameters of the healthy adolescent subjects were also collected. Sagittal alignment parameters were compared between the patients with HD and the healthy adolescent subjects, and between the pre- and postoperative parameters for the patients with HD.

RESULTS

Forty-four subjects completed the follow-up, with the average follow-up period being 18.0 months. No significant differences were detected between the HD and control groups for clinical parameters (P > 0.05). The preoperative HD group had smaller values compared with the control group in the sagittal parameters of C2-7 cervical lordosis (CL) angle, T1 slope, thoracic inlet angle (TIA), and cervical tilt angle (P < 0.05). For the patients with HD, the preoperative values were smaller compared with the postoperative HD values for the parameters of C2-7 CL angle, T1 slope, and cervical tilt angle (P < 0.05). We found no significant differences between the postoperative patients with HD and the healthy subjects, including C2-7 CL angle, C2-7 sagittal vertical axis, T1 slope, TIA, neck tilt angle, cervical tilt angle, and cranial tilt angle (P > 0.05).

CONCLUSIONS

Patients with HD have sagittal imbalance of the cervical spine compared with age-matched healthy adolescent subjects, and surgical treatment could correct the sagittal imbalance.

Anterior Cervical Discectomy and Fusion for Hirayama Disease: A Case Report and Literature Review

Hirayama disease, a juvenile muscular atrophy of the distal upper extremity, is a rare form of cervical flexion myelopathy characterized by insidiously progressive weakness of the hands and forearm muscles (i.e., painless amyotrophy). The pathognomonic finding is a markedly forward-shifted spinal cord during neck flexion, demonstrated by dynamic magnetic resonance imaging (MRI), as in a young man with muscle atrophy in the bilateral distal upper extremities. In this report, the authors describe a 31-year-old man who had the classic radiological and clinical presentations of Hirayama disease. Since prior medical treatment had been ineffective for years, he underwent multilevel instrumented anterior cervical discectomy and fusion (ACDF) to keep his subaxial cervical spine slightly-lordotic (nonflexion). His motor evoked potential amplitude improved immediately during the operation, and there were improvements of myelopathy and a modest reversal of muscle wasting at 1 year postoperatively. Postoperative dynamic cervical spine MRI also demonstrated minimal cord compression and elimination of the venous plexus engorgement dorsal to the thecal sac. Although Hirayama disease is benign in nature and frequently self-limiting, multilevel instrumented ACDF could be a reasonable management option.

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.