Multilevel Spinal Stabilization as a Treatment for Hirayama Disease: Report of an Experience with Five Cases

Post-Traumatic Central or Axial Atlantoaxial Dislocation Presenting with "Atypical" Symptoms-Analyzing the Role of Dynamic Imaging on the Basis of Experience with 14 Patients Treated by Atlantoaxial Fixation surgery

BACKGROUND

This is a report of a series of 14 patients who presented with a range of "atypical" cranial, spinal, and systemic symptoms that started after they suffered a relatively severe injury to the head and/or neck several months or years before surgical treatment. The implications of diagnosing and treating central or axial atlantoaxial dislocation (CAAD) is discussed. Also, the role of dynamic rotatory and lateral head tilt imaging in the diagnosis and treatment is analyzed.

METHODS

Of the 14 patients, 7 were men and 7 were women, with an age range of 21-64 years (average, 42 years). Due to the severity of the presenting neurological and non-neurological symptoms, all the patients had lost their occupation and were heavily dependent on painkillers and/or antidepressant drugs. In addition to other characteristic clinical and radiological evidence, CAAD was diagnosed made based on the facet alignments on lateral profile imaging in the neutral head position. Dynamic head flexion-extension, lateral head tilt, and neck rotation imaging findings confirmed and subclassified CAAD. All 14 patients underwent atlantoaxial fixation surgery.

RESULT

A personalized self-assessment clinical scoring parameter and the World Health Organization Disability Assessment Schedule 2.0 was used to evaluate the outcome. One patient did not follow-up after surgery. At a minimum follow-up of 6 months after atlantoaxial fixation surgery, the remaining 13 patients experienced relief from all major symptoms.

CONCLUSIONS

Diagnosing and treating CAAD can have major therapeutic implications for patients presenting with progressively worsening disabling clinical symptoms following relatively severe head and/or neck trauma.

Hirayama disease successfully treated by posterior fixation: a case report

Introduction and importance

Hirayama disease is a rare form of motor neuron amyotrophy that usually presents with weakness and atrophy of the distal upper extremities in young males. It is believed that it is caused by spinal cord compression during neck flexion because of the widening of the posterior extradural space. This case has been brought to attention due to its extraordinary rarity, serving as an educational tool for medical professionals and to advocate for surgical intervention when deemed necessary.

Case presentation

The authors present a case of a young male in his 20s who was diagnosed with Hirayama disease, had weakness and atrophy in both of his upper limbs, and has been successfully treated by posterior fixation at C4, C5, and C6 with lateral mass screws.

Clinical discussion

The majority of cases stabilize after 2-3 years of progression; therefore, cervical collars are generally sufficient for therapy. However, in certain serious cases with progression even after that time, surgical intervention is an option. Because this is such an uncommon incidence, surgical therapy has not been explored and is controversial.

Conclusion

The use of posterior fixation at C4, C5, and C6 with lateral mass screws as a therapy for Hirayama disease may be regarded as a successful approach.

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.

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.

Defining role of atlantoaxial and subaxial spinal instability in the pathogenesis of cervical spinal degeneration: Experience with "only-fixation" without any decompression as treatment in 374 cases over 10 years

Aim

The authors analyze their published work and update their experience with 374 cases of cervical radiculopathy and/or myelopathy related to spinal degeneration that includes ossification of the posterior longitudinal ligament (OPLL). The role of atlantoaxial and subaxial spinal instability as the nodal point of pathogenesis and focused target of surgical treatment is analyzed.

Materials and Methods

During the period from June 2012 to November 2022, 374 patients presented with acute or chronic symptoms related to radiculopathy and/or myelopathy that were attributed to degenerative cervical spondylotic changes or due to OPLL. There were 339 males and 35 females, and their ages ranged from 39 to 77 years (average 62 years). All patients were treated for subaxial spinal stabilization by Camille's transarticular technique with the aim of arthrodesis of the treated segments. Atlantoaxial stabilization was done in 128 cases by adopting direct atlantoaxial fixation in 55 cases or a modified technique of indirect atlantoaxial fixation in 73 patients. Decompression by laminectomy, laminoplasty, corpectomy, discoidectomy, osteophyte resection, or manipulation of OPLL was not done in any case. Standard monitoring parameters, video recordings, and patient self-assessment scores formed the basis of clinical evaluation.

Results

During the follow-up period that ranged from 3 to 125 months (average: 59 months), all patients had clinical improvement. Of 130 patients who had clinical evidences of severe myelopathy and were either wheelchair or bed bound, 116 patients walked aided (23 patients), or unaided (93 patients) at the last follow-up. One patient in the series was operated on 24 months after the first surgery by anterior cervical route for "adjacent segment" disc herniation. No other patient in the entire series needed any kind of repeat or additional surgery for persistent, recurrent, increased, or additional related symptoms. None of the screws at any level backed out or broke. There were no implant-related infections. Spontaneous regression of the size of osteophytes was observed in 259 patients where a postoperative imaging was possible after at least 12 months of surgery.

Conclusions

Our successful experience with only spinal fixation without any kind of "decompression" identifies the defining role of "instability" in the pathogenesis of spinal degeneration and its related symptoms. OPLL appears to be a secondary manifestation of chronic or longstanding spinal instability.

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.

Efficacy of Anterior Cervical Discectomy and Fusion for Female Patients with Hirayama Disease

OBJECTIVE

To compare the preoperative and postoperative hand function and radiographic parameters in female patients with Hirayama disease (HD).

METHODS

Consecutive female patients with HD undergoing anterior cervical discectomy and fusion were followed up. The postoperative hand functional data were obtained from the last follow-up, whereas the postoperative radiographic data were obtained from the examinations in 3- or 6-month follow-up after surgical treatments. The preoperative and postoperative data of hand functional and radiographic assessments were collected and compared between them. Logistic regression analysis was used to clear potential risk factors for surgical treatment.

RESULTS

In all, 15 female patients with HD were included in the follow-up study over 9 years. Significant differences were found in total scores (P < 0.001) and all 6 dimensions, including function (P = 0.003), activities of daily life (P = 0.002), work (P = 0.003), satisfaction (P = 0.002), appearance (P = 0.005), and HD-specific hand symptoms (P = 0.001) in hand functional assessment. The comparison of C2-C7 Cobb angle was statistically different (P = 0.042) in radiographic assessments. The course of illness was of marginal significance (P = 0.065) with curative effect of surgical treatment in logistic regression analysis.

CONCLUSIONS

Anterior cervical discectomy and fusion is an effective way to treat female patients with HD, and the course of illness may be correlated with the efficacy of surgery. For some female patients with HD with a clear diagnosis, early surgical treatment is worthy of clinical consideration.

Evolving Concepts of Craniovertebral and Spinal Instability

Weakness of the muscles of the nape of the neck and back of the spine and its related instability is the nodal point of pathogenesis of a number of clinical and pathological events at the craniovertebral junction and the spine. Whilst acute instability results in sudden and relatively severe symptoms, chronic or long-standing instability is associated with a range of musculoskeletal and structural spinal alterations. Telescoping of the spinal segments results in "vertical" spinal instability in the subaxial spine and central or axial atlantoaxial instability (CAAD) at the craniovertebral junction. Instability in such cases might not be observed on dynamic radiological imaging. Chiari formation, basilar invagination, syringomyelia, and Klippel-Feil alteration are some of the secondary alterations as a result of chronic atlantoaxial instability. Radiculopathy/myelopathy related to spinal degeneration or ossification of posterior longitudinal ligament appears to have their origin from vertical spinal instability. All the secondary alterations in the craniovertebral junction and subaxial spine that are traditionally considered pathological and to have compressive and deforming role are essentially protective in nature, are indicative of instability, and are potentially reversible following atlantoaxial stabilization. Stabilization of unstable spinal segments is the basis of surgical treatment.

Central Atlantoaxial Dislocation: Presenting Symptoms, Diagnostic Parameters, and Surgical Treatment from Reports on 15 Surgically Treated Patients

AIM

This chapter reviews the clinical entity of central or axial atlantoaxial instability (CAAD).

MATERIAL AND METHODS

From January 2018 to November 2020, 15 patients were identified as having CAAD, wherein there was no atlantoaxial instability when analyzed by conventional radiological parameters and wherein there was no evidence of neural or dural compression due to the odontoid process. The patients were identified as having atlantoaxial instability on the basis of the alignment of facets on lateral profile imaging and a range of telltale clinical and radiological indicators. The clinical statuses of the patients were recorded both before and after surgical treatment by using the specially designed Goel symptom severity index and visual analog scale (VAS) scores. All patients were treated via atlantoaxial fixation.

RESULTS

There were six men and nine women ranging in age from 18 to 45 years (average: 37 years). The presenting clinical symptoms were relatively subtle and long-standing. Apart from symptoms that are generally related to neural compromise at the craniovertebral junction, a range of nonspecific cranial and spinal symptoms were prominent. The follow-up time after surgery ranged from 6 to 34 months. All patients showed early postoperative and sustained clinical recovery.

CONCLUSIONS

The correct diagnosis and appropriate surgical treatment of CAAD can provide an opportunity for quick and lasting clinical recovery.

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.

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.

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.

Report of an eight-year experience with Camille's transarticular technique of cervical spinal stabilization

We present our experience with Camille's cervical transarticular screw fixation technique. During the period June 2012 to April 2020, 2422 screws were implanted in 321 patients by Camille's transarticular cervical spinal screw fixation technique. The indications of screw implantation were radiculopathy/myelopathy related to cervical spondylosis in 258 cases, cervical OPLL in 54 cases and Hirayama disease in 9 cases. The follow-up ranged from 6 to 92 months. In the entire series, there were no nerve or vessel injury or any other intraoperative 'complications' related to screw implantation. There was no instance of screw pull out or screw failure. There was no metal implant related infection. Satisfactory arthrodesis of all the treated spinal segments was observed on investigations done at a minimum follow-up of 6 months. Camille's transarticular screw fixation technique is a relatively simple surgical procedure and provides a safe, strong and reliable arthrodesis at the fulcrum of spinal movements.

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.

Alternative technique of C1-2-3 stabilization-sectioning of muscles attached to C2 spinous process and C2-3 fixation

Aim:

An alternative technique of C1-2-3 fixation is described that blocks the critical anteroposterior odontoid process movements and retains rotatory movement at the atlantoaxial joint. The technique involves sharp section of the muscles attached to the C2 spinous process and C2-3 transarticular interfacetal screw fixation.

Materials and Methods:

We successfully used this technique of fixation in 14 cases wherein in similar case situation; we earlier advocated inclusion of C1 in the fixation construct. Eleven patients had multisegmental spinal degeneration, 1 patient had Hirayama disease, and 2 patients had ossified posterior longitudinal ligament.

Results and Technical Advantages:

The procedure avoids manipulating C1 vertebra and excludes it from the fixation process, disables movement of C2 vertebra but retains rotation movements of the atlantoaxial joint that are executed by the muscles attached to the transverse process of atlas. The net effect is that the anteroposterior odontoid process movements that threaten the cervicomedullary neural structures are blocked and the critical rotatory atlantoaxial movements are retained.

Conclusions:

The discussed technique can be useful for cases undergoing multisegmental fixation that includes atlantoaxial joint.

Adjacent-segment "central" atlantoaxial instability and C2-C3 instability following lower cervical C3-C6 interbody fusion: Report of three cases

Aim:

We report adjacent-segment “central” or “axial” atlantoaxial instability and C2–C3 instability as the cause of delayed neurological worsening following multisegmental cervical spinal stabilization.

Materials and Methods:

Three male patients aged 34, 56, and 70 years had been operated earlier for cervical spondylosis by multilevel C3–C6 cervical interbody fusion 6–11 years earlier. After an initial improvement for few years, the patients observed relatively rapid clinical deterioration. When admitted, all the three patients were severely quadriparetic and were brought to the hospital on a wheelchair. Central atlantoaxial instability was diagnosed on the basis of our previously published clinical and radiological parameters. C2–C3 instability was essentially diagnosed on the intraoperative observations. The patients underwent atlantoaxial and C2–C3 fixation.

Results:

All the three patients had rapid clinical recovery that started in the immediate postoperative period. At an average follow-up of 21 months, the patients walked independently.

Conclusions:

Identification and treatment of adjacent-segment central atlantoaxial and C2–C3 instability can lead to gratifying clinical outcome.

Chiari 1 Formation Redefined-Clinical and Radiographic Observations in 388 Surgically Treated Patients

OBJECTIVE

The subject of Chiari formation is revisited and redefined. Results of surgical treatment of patients with Chiari formation by atlantoaxial fixation are presented.

METHODS

Results were analyzed of 388 patients with Chiari formation surgically treated during 2010 to June 2019.

RESULTS

Two hundred and sixty-six patients had syringomyelia. Two hundred and three patients had no craniovertebral bone abnormality and 74 patients had group A and 111 patients had group B basilar invagination. Twenty-nine patients had been earlier treated by foramen magnum decompression surgery with or without duroplasty. Clinical parameters, analysis of video recordings both before and after surgery, and patient self-assessment were included in the analysis of outcome. Immediate postoperative and sustained clinical improvement was observed in 385 patients (99.4%).

CONCLUSIONS

Satisfactory clinical outcome in most patients after atlantoaxial fixation and without any manipulation of neural structures, dura, or bone in the region of foramen magnum consolidates the viewpoint that atlantoaxial instability is the nodal point of pathogenesis of Chiari 1 formation. The study suggests that Chiari 1 formation may be a secondary natural neural alteration in the face of atlantoaxial instability. The role of foramen magnum decompression surgery needs to be reassessed.

Is there cervical spine muscle weakness in patients with Hirayama disease? A morphological study about cross-sectional areas of muscles on MRI

PURPOSE

Patients with Hirayama disease (HD) present with a larger range of neck flexion and show signs of cervical spine instability. Cervical spine stability largely relies on cervical spine muscles. The purpose of this study was to compare the cross-sectional areas (CSAs) of cervical spine muscles between patients with HD and healthy controls, providing some insights into whether there is cervical spine muscle weakness and incongruence in HD patients.

METHODS

In this retrospective study, cervical spine muscles CSAs of 44 HD patients, as well as that of 44 age- and sex-matched healthy counterparts, were measured on the T2-weighted axial MR images. The ratios of cervical spine muscles CSA to the corresponding vertebral body areas, defined as R-CSAs, and the flexor/extensor CSA ratios were computed and compared between two groups.

RESULTS

Compared with healthy counterparts, R-CSAs of total cervical spine muscles, total extensors, superficial extensors, and deep flexors were significantly lower in HD patients. HD patients also demonstrated a significantly greater superficial flexor/superficial extensor CSA ratio than the healthy counterparts, indicating a mismatch between superficial flexors CSA and superficial extensors CSA in HD patients.

CONCLUSIONS

In this pioneering study, HD patients had decreased size in most cervical spine muscles and a mismatch between CSAs of superficial flexor and that of superficial extensors. These results indicate generalized weakness and incongruence of cervical spine muscles, which may predispose cervical spine of HD patients to a less stable situation. These slides can be retrieved under Electronic Supplementary Material.

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.

A Review of a New Clinical Entity of 'Central Atlantoaxial Instability': Expanding Horizons of Craniovertebral Junction Surgery

The author discusses the novel form of central or axial atlantoaxial instability and analyses its clinical significance. High degree of clinical and radiological understanding of the region is mandatory to diagnose and then treat such atlantoaxial instability. Evaluation of alignment of facets of atlas and axis and observations on direct manipulation of facets of atlas and axis forms the basis of diagnosis. The treatment of clinical entities like basilar invagination, Chiari formation, syringomyelia and myelopathy related to cervical spinal degeneration, spinal deformities, ossified posterior longitudinal ligament, and Hirayama disease can be influenced by the understanding of central or axial atlantoaxial instability.

A Severe Case of Hirayama Disease Successfully Treated by Posterior Cervical Fixation without Decompression and Fusion

BACKGROUND

Hirayama disease (HD) is a rare disease traditionally treated with nonsurgical procedures. Surgical treatment, which is performed by decompression and/or fusion of the cervical spine, is generally considered for rapidly progressive or advanced cases, and the choice of surgical technique is debatable. We describe the first severe case of HD that was successfully treated by posterior lateral mass screw fixation without decompression or fusion.

CASE DESCRIPTION

The patient was a 17-year-old adolescent boy who presented with progressive symptoms bilaterally with an unsatisfactory history of conservative treatment. We performed posterior lateral mass screw fixation without decompression or fusion and removed the internal fixation after 4 years of follow-up. Symptom remission and imaging performance improvement were achieved, and the stability and range of motion of the cervical spine were maintained.

CONCLUSIONS

Nondecompression and nonfusion surgery was successful and achieved satisfactory results in this case; therefore, it serves as a promising candidate for the surgical treatment of HD.

Factors Affecting the Surgical Outcomes of Hirayama Disease: A Retrospective Analysis of Preoperative Magnetic Resonance Imaging Features of the Cervical Spine

OBJECTIVE

We explored the factors affecting the surgical outcomes of Hirayama disease (HD).

METHODS

We enrolled 40 patients with a diagnosis of HD in the present study. Cervical spine magnetic resonance imaging (MRI) was performed before surgery with the neck in the cervical neutral and flexion positions. Fusion surgery was performed at the most severely compressed 2 levels according to the flexion sagittal MRI findings. The patients were divided into improvement and no-improvement groups according to Odom's scale 6 months after surgery. The axial MRI parameters in the neutral and flexion positions at the most severely compressed segment were measured. P values < 0.05 were considered statistically significant.

RESULTS

The average age was 18.4 ± 2.27 years, and the average disease duration was 1.8 ± 1.2 years. The main symptomatic side of HD statistically matched the atrophied side of the spinal cord (P < 0.001). Based on the pathophysiology of spinal cord flattening with flexion, the parameters indicating atrophy of the spinal cord and the ability of the spinal cord to recover from flattening were significantly larger in the improvement group (P < 0.05). Receiver operating characteristic curves showed good prognostic capacity for these parameters (P < 0.05).

CONCLUSIONS

The main side of the symptoms in patients with HD corresponded with ipsilateral spinal cord atrophy found on MRI. Also, atrophy of the spinal cord in the neutral position MRI study and the ability of the spinal cord to recover were significantly related to the surgical outcome. These factors might be used as potential indications for surgery of HD.

Central or Axial Atlantoaxial Dislocation as a Cause of Cervical Myelopathy: A Report of Outcome of 5 Cases Treated by Atlantoaxial Stabilization

OBJECTIVE

The implications of diagnosis and treatment of central or axial atlantoaxial dislocation (CAAD) as a cause of symptoms of cervical myelopathy are evaluated.

METHODS

This is a report of a series of 5 patients who presented with the primary symptoms of spasticity and motor weakness and paresthesias in all the limbs. There was no evidence of any significant compression of the dural tube or neural structures at the craniovertebral junction. There was no craniovertebral junction instability when assessed by classically described radiologic parameters. CAAD was diagnosed based on our recently discussed parameter of facetal alignment, corroborative clinical and radiologic evidence, and direct observation of atlantoaxial instability by manual manipulation of the bones of the region. All patients underwent atlantoaxial fixation.

RESULTS

There was remarkable improvement in the clinical symptoms in the immediate postoperative period and during the follow-up period of 12-24 months (average, 16 months). All patients have continued to have progressive clinical recovery. Clinical assessments were done using Goel clinical evaluation scale, Japanese Orthopedic Association score, and visual analog scale.

CONCLUSIONS

Identification and treatment of CAAD can have a significant management impact on patients where the cause of spastic quadriparesis is otherwise undiagnosed.

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.

Multilevel Spinal Segmental Fixation for Kyphotic Cervical Spinal Deformity in Pediatric Age Group-Report of Management in 2 Cases

OBJECTIVE

We discuss the role of instability of multiple spinal segments including the atlantoaxial joint in the pathogenesis of cervical kyphotic deformity.

MATERIAL AND METHODS

Two male patients (5 and 17 years old) had severe cervical kyphosis and presented with symptoms related to myelopathy. The patients underwent multisegmental spinal distraction and fixation that included atlantoaxial joint. No bone decompression was done.

RESULTS

At a follow-up of >30 months, both patients had significant neurologic recovery. Investigations at follow-up showed successful arthrodesis of treated spinal segments. Although incomplete, there was recovery in kyphosis.

CONCLUSIONS

Multisegmental spinal distraction and fixation can lead to reduction in kyphosis and relief from symptoms related to myelopathy. Role of spinal instability in general and atlantoaxial joint instability in particular in pathogenesis of cervical kyphosis need to be assessed on the basis of studies with a larger number of patients.

Risk Factors for Surgical Results of Hirayama Disease: A Retrospective Analysis of a Large Cohort

OBJECTIVE

To explore risk factors affecting surgical results of Hirayama disease.

METHODS

A retrospective analysis of 210 patients was performed to identify risk factors affecting surgical results of Hirayama disease by using univariate and multivariate analyses. A receiver operating characteristic curve and area under the curve were applied to evaluate the significant results of the multivariate analysis and the optimal reference value.

RESULTS

The mean follow-up period was 27.3 months (range, 14-45 months), and 194 patients with clinical and radiographic data completed the final follow-up. Multivariate analysis identified age of patients (cutoff value 22.5 years), duration of the disease (cutoff value 33 months), physiologic reflex, and pathologic reflex as independent risk factors for surgical results of Hirayama disease. The receiver operating characteristic curve analysis and area under the curve showed that good reference value was obtained for the risk factors.

CONCLUSIONS

Age of patient, duration of the disease, physiologic reflex, and pathologic reflex are the main risk factors affecting surgical results of Hirayama disease. Receiver operating characteristic analysis shows that good reference value was obtained for the risk factors.