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.

Onasemnogene Abeparvovec Treatment after Nusinersen in an Infant with Spinal Muscular Atrophy Type 1.

BACKGROUND: Until recently, the treatment of spinal muscular atrophy (SMA) was limited to symptomatic treatment with no cure. Three innovative drugs, nusinersen, onasemnogene abeparvovec (OA), and risdiplam have been developed to treat SMA. Although the clinical trials for these drugs have demonstrated their efficacy, there is limited information on real world treatment strategies. In this study, we present a case of a male infant with SMA type 1 who underwent OA treatment after nusinersen treatment. CASE PRESENTATION: At 4 months of age, the patient was diagnosed with SMA type 1. At 6 months of age, nusinersen treatment was initiated. His motor function improved, but the effect was limited; therefore, his parents requested gene replacement therapy. During the preparation for OA treatment, anti-adeno-associated virus 9 (AAV9) antibody tests repeatedly showed non-specific reactions, which delayed initiation of treatment. The patient was put on ventilator management after he caught a common cold. During this management, the anti-AAV9 antibody test results were negative. Furthermore, the patient showed increased transaminase levels just before OA treatment; however, since these gradually decreased without signs of liver failure, we started OA treatment at 13 months of age. Four months later, the patient began to sit without support and was weaned from non-invasive positive pressure ventilation, although nasogastric tube feeding remained partially necessary. CONCLUSION: We believe that the management of unstable SMA type 1 symptoms, anti-AAV9 antibody testing, and changes in transaminase levels will be helpful for other patients with SMA who require treatment.

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.

Early Diagnosed Hirayama Disease with Unusual Symptoms Improved by Steroid Pulse Therapy.

BACKGROUND: Hirayama disease (HD), or monomelic amyotrophy, is a benign neurologic disorder mostly affecting young Asian men. It usually presents with unilateral or bilateral muscular atrophy and weakening of the upper limbs. We treated a patient with HD with bilateral hand paresthesia and weakness in 1 hand and both legs. To our knowledge, this is the first HD case including lower extremity weakness and sensory abnormalities. We improved the patient's symptoms by administering steroids in parallel with conservative treatment. CASE DESCRIPTION: A 22-year-old man visited our clinic with bilateral hand paresthesia and weakness in the right hand and both legs. He had been affected 40 days. Results of blood and cerebrospinal fluid tests were normal. Evoked potential study and brain magnetic resonance imaging (MRI) were normal. In cervical MRI, however, a lesion with high signal intensity of the C6 level on T2-weighted images was confirmed, and gray and white matter were extensively invaded. We performed empirical steroid pulse therapy before the results of blood tests to differentiate spinal demyelinating disease. MRI with neck flexion showed HD-related findings, and autoantibody tests showed no specific findings. After steroid pulse therapy, his neurologic symptoms improved within 7 days, leaving only paresthesia of toes of both feet when discharged. CONCLUSIONS: HD occurs at a young age and therefore can damage quality of life. Although the patient had unusual symptoms, the condition was diagnosed quickly, and his symptoms improved with steroid therapy. If HD is suspected, additional tests such as MRI with neck flexion should be performed and early steroid treatment might be considered.

Malignant ventricular arrhythmia in a case of adult onset of spinal muscular atrophy (Kugelberg-Welander disease).

We present a case of a 43-year-old male patient with adult onset of spinal muscular atrophy (SMA). The patient first came to our attention with atrioventricular (AV) block. A dual-chamber pacemaker (DDD-PM) was implanted. Four years later, the PM data log showed occurrence of frequent episodes of nonsustained ventricular tachycardia (NSVT). The episodes progressed in duration and frequency. An electrophysiological study revealed prolonged His-ventricular (HV) interval duration and induction of sustained ventricular tachycardia. The patient was successfully upgraded to a prophylactic dual-chamber cardioverter defibrillator. Our case is the first description of a patient with adult-onset SMA (Kugelberg-Welander disease [KWD]) and malignant ventricular arrhythmias.

Cervical laminectomy and micro resection of the posterior venous plexus in Hirayama disease.

INTRODUCTION: Hirayama disease is a rare cervical myelopathy predominantly affecting young adults and mainly found in Asia. It results in a pure motor distal lesion of the upper limbs with slow progression. Dynamic magnetic resonance imaging (MRI), which allows the diagnosis to be made, shows a typical appearance of anterior compression of the cervical spinal cord associated with enlargement of the posterior epidural spaces due to a dilated venous plexus. Surgery is considered when conservative treatment has failed. However, the type of surgery is not well standardized in this compressive myelopathy. METHODS: We report on three patients with Hirayama disease operated using an original method: cervical decompressive laminectomy and coagulation of the posterior epidural plexus without fixation. The clinical, radiological and surgical data of these three patients were analyzed. Each patient underwent postoperative MR imaging. RESULTS: The mean age at diagnosis was 18.6 years (16-20 years) with a history of progressive symptoms lasting 1 to 4 years before treatment. Follow-up was 21 to 66 months after surgery. Neurological and electrophysiological improvement was noted in two patients; the third had stabilized. Postoperative MRI confirmed normalization of flexion imaging on MRI. None of the three patients complained of disabling neck pain. CONCLUSION: Posterior cervical decompression with coagulation of epidural venous plexus is a technique that seems effective in Hirayama disease in young subjects. It effectively treats patients by avoiding permanent cervical fixation.

New quantitative method for evaluation of motor functions applicable to spinal muscular atrophy.

OBJECTIVE: The aim of this study was to develop and introduce new method to quantify motor functions of the upper extremity. METHODS: The movement was recorded using a three-dimensional motion capture system, and the movement trajectory was analyzed using newly developed two indices, which measure precise repeatability and directional smoothness. Our target task was shoulder flexion repeated ten times. We applied our method to a healthy adult without and with a weight, simulating muscle impairment. We also applied our method to assess the efficacy of a drug therapy for amelioration of motor functions in a non-ambulatory patient with spinal muscular atrophy. Movement trajectories before and after thyrotropin-releasing hormone therapy were analyzed. RESULTS: In the healthy adult, we found the values of both indices increased significantly when holding a weight so that the weight-induced deterioration in motor function was successfully detected. From the efficacy assessment of drug therapy in the patient, the directional smoothness index successfully detected improvements in motor function, which were also clinically observed by the patient's doctors. CONCLUSION: We have developed a new quantitative evaluation method of motor functions of the upper extremity. Clinical usability of this method is also greatly enhanced by reducing the required number of body-attached markers to only one. This simple but universal approach to quantify motor functions will provide additional insights into the clinical phenotypes of various neuromuscular diseases and developmental disorders.

[Cervical collar therapy for juvenile muscular atrophy of distal upper extremity (Hirayama disease): results from 38 cases].

BACKGROUND: Juvenile muscular atrophy of distal upper extremity is a peculiar type of cervical myelopathy affecting young people characterized by localized amyotrophy in the forearm and hand that is initially progressive, and then stabilized in a few years. The anterior horn cell damage may be induced by forward displacement of the lower cervical dural sac and spinal cord on neck flexion. We proposed that the forward displacement was one of pathogenic factors, and reported that therapeutic intervention using a cervical collar in order to minimize neck flexion halted the progressive weakness in some patients. OBJECTIVE: To examine effectiveness of cervical collar treatment for this disease and to investigate clinical and radiological profiles that predict a favorable outcome before treatment. METHODS: Thirty-eight patients who had progressive illness within 5 years after onset underwent cervical collar therapy (treatment group). Forty-five patients in a previous case series without any therapeutic intervention made up a control group. The duration of progressive phase of illness was compared between the two groups. In the treatment group, the time interval from onset and the measurements of cervical cord atrophy and its flattening on neck flexion at the introduction of treatment by CT-myelography or MRI were analyzed with respect to prognosis. RESULTS: All the patients in the treatment group showed no further progression after introduction of treatment. The duration of the progressive period was shorter in the treatment group (mean 1.8 +/- 1.2 years) than in the control group (mean 3.2 +/- 2.3 years) (p < 0.005). In the treatment group, 15 of 31 patients within 2.5 years after the onset showed not only stabilization but also improvement of muscular weakness or cold paresis. Five of 7 patients who had no or mild cord atrophy at the introduction showed improvement after treatment. CONCLUSION: Cervical collar therapy induces a premature arrest of this disease. Improvement is expected in patients who have shorter duration of illness and have mild cord atrophy in a neutral neck position. Early diagnosis and therapeutic intervention may minimize the functional disability of young patients.

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

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

[Suspected Hirayama disease. Presentation of a case and a clinical review]. / Sospecha de enfermedad de Hirayama. A propósito de un caso en Atención Primaria. Revisión clínica.

Hirayama's disease, or juvenile muscular atrophy of distal upper extremity, is a cervical myelopathy. It affects adolescent males, and is characterized by progressive muscle weakness and atrophy of the distal upper extremities, followed by slow paralysis. Although the cause remains unclear, radiological findings suggest neuropathic forward displacement of the posterior cervical dural sac during neck flexion, causing compression of the cervical cord, resulting in atrophic changes and ischemic disease of the medullar anterior horn. Since the bending of the neck was recognized as a cause of the disease, cervical orthosis, spinal fusion, and duraplasty combined with fusion, have been proposed as treatment. A solid understanding of Hirayama disease is critical as early recognition and effective treatment can stop the deterioration.