Duchenne muscular dystrophy: the management of scoliosis

Cardiomyopathy in Duchenne Muscular Dystrophy and the Potential for Mitochondrial Therapeutics to Improve Treatment Response

Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disease caused by mutations to the dystrophin gene, resulting in deficiency of dystrophin protein, loss of myofiber integrity in skeletal and cardiac muscle, and eventual cell death and replacement with fibrotic tissue. Pathologic cardiac manifestations occur in nearly every DMD patient, with the development of cardiomyopathy-the leading cause of death-inevitable by adulthood. As early cardiac abnormalities are difficult to detect, timely diagnosis and appropriate treatment modalities remain a challenge. There is no cure for DMD; treatment is aimed at delaying disease progression and alleviating symptoms. A comprehensive understanding of the pathophysiological mechanisms is crucial to the development of targeted treatments. While established hypotheses of underlying mechanisms include sarcolemmal weakening, upregulation of pro-inflammatory cytokines, and perturbed ion homeostasis, mitochondrial dysfunction is thought to be a potential key contributor. Several experimental compounds targeting the skeletal muscle pathology of DMD are in development, but the effects of such agents on cardiac function remain unclear. The synergistic integration of small molecule- and gene-target-based drugs with metabolic-, immune-, or ion balance-enhancing compounds into a combinatorial therapy offers potential for treating dystrophin deficiency-induced cardiomyopathy, making it crucial to understand the underlying mechanisms driving the disorder.

Current Concepts in the Orthopaedic Management of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD), a genetic condition marked by progressive muscle degeneration, presents notable orthopaedic challenges, especially scoliosis, which deteriorates patients' quality of life by affecting sitting balance and complicating cardiac and respiratory functions. Current orthopaedic management strategies emphasize early intervention with corticosteroids to delay disease progression and the use of surgical spinal fusion to address severe scoliosis, aiming to enhance sitting balance, alleviate discomfort, and potentially extend patient lifespan. Despite advancements, optimal management requires ongoing research to refine therapeutic approaches, ensuring improved outcomes for patients with DMD. This review synthesizes recent findings on surgical and nonsurgical interventions, underscoring the importance of a multidisciplinary approach tailored to the dynamic needs of patients with DMD.

Timed rolling and rising tests in Duchenne muscular dystrophy ambulant boys: a feasibility study

BACKGROUND

Functional activities are extensively used in motor assessments of patients with Duchenne muscular dystrophy. The role of timed items has been reported as an early prognostic factor for disease progression. However, there are two functional activities that are not widely assessed in clinical practice among Duchenne muscular dystrophy patients: rolling and bed rising. This study aimed to investigate whether the 360-degree roll (roll) and supine to sit-to-edge (bed rise) measurements are feasible tools reflecting the functional status of ambulatory DMD children by establishing possible correlations between validated measures: the Vignos Scale (VS), timed rise from floor and the 6-Minute Walk Test (6MWT).

METHODS

A total of 32 ambulant boys with DMD were assessed using timed items, the 6MWT and VS.

RESULTS

The roll and bed rise are correlated with each other. The 6MWT, the floor rise and VS are correlated with the roll and with the bed rise.

CONCLUSIONS

Findings offer preliminary empirical evidence addressing feasibility and safety of roll and bed rise measurements. There is a potential clinical utility of these tests in assessing functional status of DMD ambulant patients.

Prognostic Utility of Cardiovascular Magnetic Resonance-Based Phenotyping in Patients With Muscular Dystrophy

Background The prognostic utility of cardiovascular magnetic resonance imaging, including strain analysis and tissue characterization, has not been comprehensively investigated in adult patients with muscular dystrophy. Methods and Results We prospectively enrolled 148 patients with dystrophinopathies (including heterozygotes), limb-girdle muscular dystrophy, and type 1 myotonic dystrophy (median age, 36.0 [interquartile range, 23.0-50.0] years; 51 [34.5%] women) over 7.7 years in addition to an age- and sex-matched healthy control cohort (n=50). Cardiovascular magnetic resonance markers, including 3-dimensional strain and fibrosis, were assessed for their respective association with major adverse cardiac events. Our results showed that markers of contractile performance were reduced across all muscular dystrophy groups. In particular, the dystrophinopathies cohort experienced reduced left ventricular (LV) ejection fraction and high burden of replacement fibrosis. Patients with type 1 myotonic dystrophy showed a 26.8% relative reduction in LV mass with corresponding reduction in chamber volumes. Eighty-two major adverse cardiac events occurred over a median follow-up of 5.2 years. Although LV ejection fraction was significantly associated with major adverse cardiac events (adjusted hazard ratio [aHR], 3.0 [95% CI, 1.4-6.4]) after adjusting for covariates, peak 3-dimensional strain amplitude demonstrated greater predictive value (minimum principal amplitude: aHR, 5.5 [95% CI, 2.5-11.9]; maximum principal amplitude: aHR, 3.3 [95% CI, 1.6-6.8]; circumferential amplitude: aHR, 3.4 [95% CI, 1.6-7.2]; longitudinal amplitude: aHR, 3.4 [95% CI, 1.7-6.9]; and radial strain amplitude: aHR, 3.0 [95% CI, 1.4-6.1]). Minimum principal strain yielded incremental prognostic value beyond LV ejection fraction for association with major adverse cardiac events (change in χ2=13.8; P<0.001). Conclusions Cardiac dysfunction is observed across all muscular dystrophy subtypes; however, the subtypes demonstrate distinct phenotypic profiles. Myocardial deformation analysis highlights unique markers of principal strain that improve risk assessment over other strain markers, LV ejection fraction, and late gadolinium enhancement in this vulnerable patient population.

Distal fusion in Duchenne scoliosis: the relevance of preoperative pelvic obliquity. A case series study

PURPOSE

The aim of this study was to determine clinical and radiographic outcomes for Duchenne Muscular Dystrophy (DMD) patients who underwent posterior spinal fusion from T2/3 to L5 (without pelvic fixation), at this single centre.

METHODS

From January 2012 to January 2020, 29 consecutive DMD scoliosis patients underwent posterior spinal fusion using pedicle screws from T2/3 to L5 in a single center with a minimum of 3 years follow-up (FU). Radiologic measurements and chart review were performed.

RESULTS

Twenty nine patients aged 14 ± 1.5 years were included. No patient was lost to FU. All patients had significant correction in Cobb angle, pelvic obliquity (PO) and lumbar lordosis (LL), without loss of correction at last FU. The mean values for preoperative, immediate postoperative and last FU were CA 62o, 15o and 17o, PO: 21o, 8o and 9o; and LL 10o, -41o and -41o respectively. Correction in CA was independent of any variable analysed including implant density, rod diameter, traction, or bone density. Regarding PO, it was inversely related to age and independent of all other variables. Factors associated with postoperative complications were age and respiratory function.

CONCLUSIONS

It appears from our results that pelvic fixation might not always be required in DMD scoliosis surgery, when using pedicle screws with lowest instrumented vertebra at L5. However, larger preoperative PO values can be related with residual PO. It seems that probably related to the underlying condition, early surgery may decrease incidence of complications.

LEVEL OF EVIDENCE

IV.

Case report: Novel frameshift mutation in LAMA2 gene causing congenital muscular dystrophy type 1A

Congenital muscular dystrophy type 1A (CMD1A) is a rare autosomal recessive disorder caused by mutations in the LAMA2 gene. CMD1A is characterized by peripheral hypotonia and muscle weakness from the first months of life, cerebral white matter abnormalities, and elevated creatine phosphokinase (CPK) levels. We describe an 8-year-old girl from Colombia with clinical features compatible with CMD1A, severe scoliosis corrected with surgery, and feeding difficulty corrected with a gastrostomy. Whole-exome sequencing identified two heterozygous variants: a reported nonsense variant (LAMA2 NM_000426.3:c.4198C>T) and a novel likely pathogenic variant (LAMA2 NM_000426.3:c.9227_9243dup). This is the first genetically confirmed case of CMD1A in Colombia and the first report of the c.9227_9243dup variant causing CMD1A.

PCYT2-regulated lipid biosynthesis is critical to muscle health and ageing

Muscle degeneration is the most prevalent cause for frailty and dependency in inherited diseases and ageing. Elucidation of pathophysiological mechanisms, as well as effective treatments for muscle diseases, represents an important goal in improving human health. Here, we show that the lipid synthesis enzyme phosphatidylethanolamine cytidyltransferase (PCYT2/ECT) is critical to muscle health. Human deficiency in PCYT2 causes a severe disease with failure to thrive and progressive weakness. pcyt2-mutant zebrafish and muscle-specific Pcyt2-knockout mice recapitulate the participant phenotypes, with failure to thrive, progressive muscle weakness and accelerated ageing. Mechanistically, muscle Pcyt2 deficiency affects cellular bioenergetics and membrane lipid bilayer structure and stability. PCYT2 activity declines in ageing muscles of mice and humans, and adeno-associated virus-based delivery of PCYT2 ameliorates muscle weakness in Pcyt2-knockout and old mice, offering a therapy for individuals with a rare disease and muscle ageing. Thus, PCYT2 plays a fundamental and conserved role in vertebrate muscle health, linking PCYT2 and PCYT2-synthesized lipids to severe muscle dystrophy and ageing.

Reduced bone mineral density in adolescents with Duchenne Muscular Dystrophy (DMD) and scoliosis

Duchenne muscular dystrophy is a progressive disease usually associated with loss of ambulation and progressive scoliosis. Immobilisation and glucocorticoid treatment are predisposing factors for reduced bone mineral density (BMD). Analysis of quantitative computed tomography revealed low BMD in thoracic and lumbar vertebrae in comparison to age- and sex-matched healthy controls.

INTRODUCTION

Evaluation of vertebral bone mineral density (BMD) in Duchenne Muscular Dystrophy (DMD) adolescents with untreated advanced scoliosis and comparison with the BMD values of healthy age-matched controls, based on quantitative computer tomography.

METHODS

Thirty-seven DMD adolescents (age 15.6 ± 2.5 years) with spinal deformity were evaluated clinically and radiologically prior to definite spinal fusion and compared to 31 male and age-matched healthy individuals (age 15.7 ± 2.3 years). Data related to previous medical treatment, physiotherapy and ambulatory status was also analysed. Scoliotic curves were measured on plain sitting radiographs of the spine. The BMD Z-scores of the thoracic and lumbar vertebrae were calculated with QCTpro® (Mindways Software Inc., USA), based on data sets of preoperative, phantom pre-calibrated spinal computed tomography scans.

RESULTS

A statistically significant lower BMD could be found in DMD adolescents, when compared to healthy controls, showing an average value for the lumbar spine of 80.5 ± 30.5 mg/cm³. Z-scores deteriorated from the upper thoracic towards the lower lumbar vertebrae. All but the uppermost thoracic vertebrae had reduced BMD values, with the thoracolumbar and lumbar region demonstrating the lowest BMD. No significant correlation was observed between BMD and the severity of the scoliotic curve, previous glucocorticoid treatment, cardiovascular impairment, vitamin D supplementation, non-invasive ventilation or physiotherapy.

CONCLUSION

DMD adolescents with scoliosis have strongly reduced BMD Z-scores, especially in the lumbar spine in comparison to healthy controls. These findings support the implementation of a standardised screening and treatment protocol. Level of evidence/clinical relevance: therapeutic level III.

Corticosteroid use and bone health management for Duchenne muscular dystrophy in South Korea

This study aimed to determine the current corticosteroid use and bone health management status of patients with Duchenne muscular dystrophy (DMD) in South Korea. This is a national population-based study utilized information from the databased of Korean National Health Insurance Database. Database regarding bone status, spine radiography findings, bone mineral density, and laboratory test results were obtained, as well as the proportion of patients with spine and lower limb prostheses, occurrence of scoliosis, and age at scoliosis surgery. Deflazacort dose in the ambulant group (aged < 15 years) increased by age and year. The maintenance dose of prednisolone and deflazacort for the 15–19 years group decreased by year. Among the patients, 12.47% underwent spine radiography, 23.11% underwent dual-energy X-ray absorptiometry, and 22.7% underwent vitamin D tests. Moreover, 40.9% of the patients were prescribed vitamin D at a mean age of 14.6 ± 6.1 years, while 10.22% were prescribed bisphosphonate at 17.92 ± 3.4 years. Further, 16.1% of the patients underwent posterior spinal instrumentation and fusion at 14.4 ± 2.3 years and 5.3% underwent anterior spinal instrumentation and fusion at 14.4 ± 2.3 years. Ankle–foot orthosis and spine orthosis prescriptions were noted in 4.91% and 1.84% of patients, respectively. In this our study, the current corticosteroid use and bone health management status of DMD in South Korea has been presented. The dose prescription for corticosteroid and bone health monitoring did not reach to current recommendation.

Surveying Therapists on Seating Approaches for Patients with Muscular Dystrophy in Japan

Patients with muscular dystrophy (MD) need fitted wheelchairs. This study aimed to ascertain physiotherapists and occupational therapists’ opinions about the current wheelchair seating process for patients with MD in Japan. We identified 266 academic papers published between August 2014 and July 2019 with the keywords “muscular dystrophy” and either “physiotherapy” or “occupational therapy.” We then sent survey requests to 140 physiotherapists and occupational therapists (who were among the authors of the aforementioned papers), of whom 41 agreed to partake in this study. We found that the time required for each seating was 30–60 min for three types of MD, and the most commonly reported time to trial fitting was 1–3 months. In addition, health insurance reimbursements for seating were considered part of disease-specific rehabilitation in most cases, and most therapists were more or less satisfied with the current seating procedure. Physiotherapists had the highest degree of reflection of their views (wishes) regarding seating, followed by MDs and their families. In Japan, seating has been regarded as a medical practice since 2017. In the future, we would like to investigate the seating concept for individual therapists in detail.

Surgical treatment of scoliosis in Ullrich Congenital Muscular Dystrophy: a case series of 3 patients

Scoliosis in Ullrich Congenital Muscular Dystrophy (UCMD) is very common, with a reported incidence of more than 50%, and it is rapidly progressive. There are no previous studies which specifically focus on scoliosis surgery in UCMD patients. This article reports three cases of scoliosis surgery in UCMD, focusing on operative course, clinical and radiological results achieved, fusion area and complications, with a 2-year follow-up. The surgical technique adopted for vertebral arthrodesis included: high-density pedicle screw systems, asymmetric rods contouring and direct vertebral rotation. The summary results shown a significative correction of the coronal deformity, with a reduction of the mean Cobb angle from 49° to 25° post-operatively. Mean pelvic tilt remained stable, while L5-tilt showed a decrease from 10° to 6°. Mean screw density was 1.92. None of the patients required extended fixation to S2. No major complications were reported, and patients maintained their pre-operative walking ability. All the patients reported a subjective improvement in quality of life, with a better sitting comfort. In conclusion, posterior spinal fusion with high-density pedicle screw systems and direct vertebral rotation may be safe and effective in surgical correction of scoliosis in UCMD. If pelvic obliquity and L5-tilt are less than 15°, could be possible to achieve an optimal spinal and pelvic balance even without sacral or pelvic fixation.

N, Ramprasad VL, Gupta R, Seshagiri S, Nongthomba U, Phalke S. Matrilineal analysis of mutations in the DMD gene in a multigenerational South Indian cohort using DMD gene panel sequencing

BACKGROUND

Duchenne muscular dystrophy (DMD) is an X-linked recessive neuromuscular disorder characterised by progressive irreversible muscle weakness, primarily of the skeletal and the cardiac muscles. DMD is characterised by mutations in the dystrophin gene, resulting in the absence or sparse quantities of dystrophin protein. A precise and timely molecular detection of DMD mutations encourages interventions such as carrier genetic counselling and in undertaking therapeutic measures for the DMD patients.

RESULTS

In this study, we developed a 2.1 Mb custom DMD gene panel that spans the entire DMD gene, including the exons and introns. The panel also includes the probes against 80 additional genes known to be mutated in other muscular dystrophies. This custom DMD gene panel was used to identify single nucleotide variants (SNVs) and large deletions with precise breakpoints in 77 samples that included 24 DMD patients and their matrilineage across four generations. We used this panel to evaluate the inheritance pattern of DMD mutations in maternal subjects representing 24 DMD patients.

CONCLUSION

Here we report our observations on the inheritance pattern of DMD gene mutations in matrilineage samples across four generations. Additionally, our data suggest that the DMD gene panel designed by us can be routinely used as a single genetic test to identify all DMD gene variants in DMD patients and the carrier mothers.

Respiratory decline in adult patients with Becker muscular dystrophy: A longitudinal study

Becker muscular dystrophy (BMD) is a rare hereditary neuromuscular disease, caused by a genetic defect in the Duchenne Muscular Dystrophy (DMD) gene. We studied the natural history of respiratory function and its affecting factors in 23 adult BMD patients. These important data are needed for (future) clinical trials in BMD but are largely lacking. Patients had a median age of 51 years (28-78y) and median follow-up duration of 14 years (2-25y). We analysed 190 pulmonary function measurements with a median interval of one year (1-17y) and measured a 1.00% decline of Forced Vital Capacity percent predicted (FVC%pred) per year (p = 0.004). Loss of ambulation significantly increased the annual rate of FVC decline and was dependent of patient's body mass index (BMI; p = 0.015), with increases in BMI correlating with an even more rapid deterioration of FVC. A decline in Medical Research Council (MRC) sum score was significantly correlated with a decline in FVC (p = 0.003). We conclude that adult BMD patients experience a significant but mild respiratory decline. However, this decline is significantly more rapid and clinically relevant after loss of ambulation, which warrants a more vigilant follow-up of respiratory function in this subgroup.

Magnetic Resonance Imaging Studies in Duchenne Muscular Dystrophy: Linking Findings to the Physical Therapy Clinic

Duchenne muscular dystrophy (DMD) is a muscle degenerative disorder that manifests in early childhood and results in progressive muscle weakness. Physical therapists have long been an important component of the multidisciplinary team caring for people with DMD, providing expertise in areas of disease assessment, contracture management, assistive device prescription, and exercise prescription. Over the last decade, magnetic resonance imaging of muscles in people with DMD has led to an improved understanding of the muscle pathology underlying the clinical manifestations of DMD. Findings from magnetic resonance imaging (MRI) studies in DMD, paired with the clinical expertise of physical therapists, can help guide research that leads to improved physical therapist care for this unique patient population. The 2 main goals of this perspective article are to (1) summarize muscle pathology and disease progression findings from qualitative and quantitative muscle MRI studies in DMD and (2) link MRI findings of muscle pathology to the clinical manifestations observed by physical therapists with discussion of any potential implications of MRI findings on physical therapy management.

Glucocorticoid-Associated Demise of a Patient With Duchenne Muscular Dystrophy

We describe the clinical deterioration of a 26-yr-old man with Duchenne muscular dystrophy on oral daily high-dose deflazacort. Although this daily regimen was targeted to benefit ambulation and respiration, it resulted in premature death with lethal sequelae from liver failure, decubiti, diabetes mellitus, and morbid obesity. This case illustrates the need for further research weighing risk versus benefit of daily glucocorticoid therapy, specifically deflazacort, in Duchenne muscular dystrophy patients. Thus, curtailment of daily dosing to eliminate dire sequelae in patients living longer into adulthood than ever before is recommended.

Real-world outcomes of long-term prednisone and deflazacort use in patients with Duchenne muscular dystrophy: experience at a single, large care center

Aim: To assess outcomes among patients with Duchenne muscular dystrophy receiving deflazacort or prednisone in real-world practice. Methods: Clinical data for 435 boys with Duchenne muscular dystrophy from Cincinnati Children’s Hospital Medical Center were studied retrospectively using time-to-event and regression analyses. Results: Median ages at loss of ambulation were 15.6 and 13.5 years among deflazacort- and prednisone-initiated patients, respectively. Deflazacort was also associated with a lower risk of scoliosis and better ambulatory function, greater % lean body mass, shorter stature and lower weight, after adjusting for age and steroid duration. No differences were observed in whole body bone mineral density or left ventricular ejection fraction. Conclusion: This single center study adds to the real-world evidence associating deflazacort with improved clinical outcomes.

Neurodevelopmental, behavioral, and emotional symptoms in Becker muscular dystrophy

INTRODUCTION

Becker muscular dystrophy (BMD) results in decreased dystrophin with implications for mental health.

METHODS

This is a retrospective case series of neurodevelopmental, behavioral, and emotional symptoms and respective pharmacotherapies of 70 patients with BMD.

RESULTS

Fifty-four (77.1%) patients exhibited at least one symptom, and 19 (27.1%) patients exhibited four or more symptoms. The most prevalent symptoms were specific learning disabilities or special education needs (31.4%), inattention/hyperactivity (35.7%), language/speech delays (35.7%), and emotional or behavioral dysregulation (38.6%). Fisher's exact tests indicated that anxiety was more prevalent with mutations upstream of exon 30 (P = .049), but the prevalence of other symptoms did not differ with respect to mutation sites. Similarly, the number of symptoms individual patients with BMD exhibited did not differ with respect to mutation sites. Seventeen (24.3%) patients required pharmacotherapy to manage symptoms.

DISCUSSION

Neurodevelopmental, behavioral, and emotional symptoms are prevalent in patients with BMD regardless of dystrophin gene mutation site.

The Impact of Body Mass Index (BMI) on 30-day Outcomes Following Posterior Spinal Fusion in Neuromuscular Scoliosis

STUDY DESIGN

Retrospective.

OBJECTIVE

Assess the impact of varying severity of BMI on 30-day outcomes following posterior spinal fusions in neuromuscular scoliosis.

SUMMARY OF BACKGROUND DATA

Obesity in the pediatric population is shown to be associated with adverse outcomes across varying specialties. The weight-outcome relationship in neuromuscular scoliosis has not been thoroughly investigated.

METHODS

The 2012-2016 American College of Surgeons - National Surgical Quality Improvement (ACS-NSQIP) database was queried using Current Procedural Terminology codes 22800, 22802, and 22804 to identify patients undergoing posterior spinal fusion for neuromuscular scoliosis only. BMI was classified into four groups based on the Center for Disease Control (CDC) BMI-for-age percentile chart - Normal weight (BMI ≥5th to <85th percentile), Underweight (<5th percentile), Overweight (≥85th to <95th percentile) and Obese (≥95th percentile). Multivariate regression models were built to understand the impact of varying BMI severity classes on 30-day outcomes.

RESULTS

A total of 1291 patients underwent posterior spinal fusion for neuromuscular scoliosis. A total of 695 (53.8%) were normal weight, 286 (22.2%) were underweight, 145 (11.2%) were overweight, and 165 (12.8%) were obese. Obese patients versus normal weight patients were at a significantly higher risk of surgical site infections (OR 2.15; P = 0.035), wound dehiscence (OR 1.58; P = 0.037), urinary tract infections (OR 3.41; P = 0.010), and 30-day readmissions (OR 1.94; P = 0.029). Of note, overweight versus normal weight individuals had higher odds of cardiopulmonary complications (OR 8.82; P = 0.024). No significant associations were seen for varying BMI and other 30-day outcomes.

CONCLUSIONS

Obese neuromuscular patients undergoing PSF have higher odds of experiencing adverse outcomes, particularly surgical site infections, urinary tract infections, and readmissions. Providers should promote prevention strategies, such as dietary modification and/or early physical activity in these high-risk patients to minimize the risks of experiencing complications in the acute postoperative period.

LEVEL OF EVIDENCE

3.

Peptide-conjugate antisense based splice-correction for Duchenne muscular dystrophy and other neuromuscular diseases

Duchenne muscular dystrophy (DMD) is an X-linked disorder characterized by progressive muscle degeneration, caused by the absence of dystrophin. Exon skipping by antisense oligonucleotides (ASOs) has recently gained recognition as therapeutic approach in DMD. Conjugation of a peptide to the phosphorodiamidate morpholino backbone (PMO) of ASOs generated the peptide-conjugated PMOs (PPMOs) that exhibit a dramatically improved pharmacokinetic profile. When tested in animal models, PPMOs demonstrate effective exon skipping in target muscles and prolonged duration of dystrophin restoration after a treatment regime. Herein we summarize the main pathophysiological features of DMD and the emergence of PPMOs as promising exon skipping agents aiming to rescue defective gene expression in DMD and other neuromuscular diseases. The listed PPMO laboratory findings correspond to latest trends in the field and highlight the obstacles that must be overcome prior to translating the animal-based research into clinical trials tailored to the needs of patients suffering from neuromuscular diseases.

Scoliosis in Duchenne muscular dystrophy children is fully reducible in the initial stage, and becomes structural over time

BACKGROUND

Patients with Duchenne muscular dystrophy (DMD) often develop scoliosis that progresses rapidly after loss of ambulation. Management of scoliosis is crucial because it affects both life expectancy and quality of life of patients with DMD. Spinal orthosis attempts to prevent or delay scoliosis using spinal support at three points of the controlling mechanism; the curve should be flattened by the pressure. Therefore, it is assumed that spine flexibility could be a significant influencing factor for the effectiveness of braces. Hence, we attempted to investigate the flexibility of scoliosis in non-ambulant patients with DMD.

METHODS

We reviewed the medical records of 273 boys who were genetically identified as having DMD, and finally, 50 boys with serial records of radiographs after loss of ambulation were finally enrolled. And among them, only 31 patients developed scoliosis. Spine radiographs in sitting and supine positions were also reviewed to obtain Cobb angle, curve flexibility, and pelvic obliquity. Flexibilities (%) were calculated by the difference in angles between the sitting and supine positions divided by the angle at the sitting position, multiplied by 100.

RESULTS

Among 31 boys who had scoliosis, all but 2 boys with curves went through a sequential course of 1) no scoliosis, 2) nonstructural scoliosis, when scoliosis was only measurable in the sitting position, and 3) structural scoliosis, when scoliosis was also detectable in the supine position. Flexibility decreased each year after detection of scoliosis in those who developed scoliosis the first year, from 75.5 ± 5.0% to 57.1 ± 10.5% and to 49.1 ± 10.0% (mean ± standard deviation). Spinal flexibility was significantly correlated with curve magnitude of scoliosis in both sitting and supine position (p < 0.05, respectively).

CONCLUSIONS

There is a period of fully reducible curve in DMD patients at the initial stage of scoliosis. Afterward, as spinal curve progresses, flexibility decreases over time. To detect the scoliosis when the curve is fully reducible, scoliosis curve in DMD patients should be evaluated dynamically, including radiographs of at least in two different positions.

Long-term treatment with eteplirsen in nonambulatory patients with Duchenne muscular dystrophy

This analysis aims to describe the outcomes of two nonambulatory patients with Duchenne muscular dystrophy (DMD) who participated in two clinical studies. The two consecutive trials of eteplirsen (studies 201 and 202) were conducted in patients with DMD (N = 12) and confirmed genetic mutations amenable to exon 51 skipping.In study 201, 12 patients were randomized to receive once-weekly, double-blind intravenous infusions of eteplirsen 30 or 50 mg/kg or placebo for 24 weeks; patients then received open-label eteplirsen during weeks 25 through 28. All 12 patients continued onto open-label extension study 202 and received long-term treatment with eteplirsen. We compared cardiac, pulmonary, and upper limb function and dystrophin production in the nonambulatory twin patients versus the 10 ambulatory patients through 240 combined treatment weeks.Ten study patients remained ambulatory through both studies, while the identical twin patients both experienced early, rapid loss of ambulation. The twin patients had greater disease severity at baseline (6-minute walk test [6MWT], 330 and 256 m) versus the other patients (n = 10; 6MWT range, 341-418 m). They maintained cardiac and upper limb function through combined week 240, with outcomes similar to those of the patients who remained ambulatory. Dystrophin production was confirmed following eteplirsen treatment.Despite the loss of ambulation, other markers of disease progression remained relatively stable in the eteplirsen-treated twin patients and were similar to those of the ambulatory patients.

Current concepts in neuromuscular scoliosis

PURPOSE OF REVIEW

Spinal deformity is a common issue in pediatric patients with an underlying neurological diagnosis or syndrome. Management of neuromuscular scoliosis (NMS) is a major part of the orthopedic care of such patients, as the deformity is often progressive, and may affect gait, seating and positioning. In addition, untreated large spinal deformities may be associated with pain and/or cardiopulmonary issues over time.

RECENT FINDINGS

Recent changes in medical management of the underlying disease process appears to alter the natural history of certain neuromuscular conditions, and in the case of patients with Duchenne's muscular dystrophy significantly diminish the incidence of spinal deformity. In the most common diagnosis associated with NMS, cerebral palsy, there is evidence that despite a high complication rate, surgical management of spinal deformity is associated with measurable improvements in validated health-related quality-of-life measures. Spinal deformity is a common finding in patients with neurological diagnoses. It is important for those involved in the care of these patients to understand the natural history of NMS, as well as the potential risks and benefits to the patient and caregivers, of surgical and non-surgical interventions.

A new era in the management of Duchenne muscular dystrophy

The management of Duchenne muscular dystrophy (DMD) has changed considerably over the last few decades. Standards of care have recently been updated, based on systematic reviews of the literature and structured, case-based consensus discussions of experts. Besides addressing muscular function, these recommendations cover most areas of organ involvement and psychosocial issues. Studies employing animal models investigating basic disease mechanisms have increased considerably. Development of valid functional outcome measures enabled high-evidence, clinical trials in males with DMD. Stop codon readthrough with ataluren has revealed some effect in patients with moderate disability and has been approved for males with suitable mutations who are still ambulant. Exon 51 skipping with eteplirsen demonstrated a structural and functional effect in a small group of patients and received restricted approval in the USA. Further trials investigating a broad range of mechanisms are underway. However, much more work is needed to develop more active treatments that stop disease progression. Likewise, the distribution of complex and expensive therapies to underprivileged patients and those in poorer regions must be improved. WHAT THIS PAPER ADDS: Updated standards of care covering most clinical aspects of Duchenne muscular dystrophy (DMD) are available. Adequately controlled clinical trials have allowed initial approval of disease-modifying drugs for small groups of patients. Scientific, economic, and political efforts are needed to make effective therapies available more quickly. Effective therapies should be made available more quickly to patients in low-income regions.

Clinical management of Duchenne muscular dystrophy: the state of the art

INTRODUCTION

Duchenne muscular dystrophy (DMD) is a devastating, progressive neuromuscular disorder for which there is no cure. As the dystrophin gene is located on the X chromosome, DMD occurs predominately in males. DMD is caused by a lack of functional dystrophin protein resulting from mutations in the 2.2-Mb DMD gene, whichdisrupts the reading frame. Care considerations for DMD advocate a coordinated, multidisciplinary approach to the management of DMD in order to optimize management of the primary manifestations of DMD as well as any secondary complications that may arise.

METHODS

This review provides an overview of the multidisciplinary clinical management of DMD with regard to the respiratory, cardiology, orthopedic, and nutritional needs of patients with DMD. Recent advances in novel disease-modifying treatments for DMD are also discussed with specific reference to exon skipping and suppression of premature stop codons as promising genetic therapies.

RESULTS

The combination of multidisciplinary clinical management alongside novel gene therapiesoffers physicians a powerful armamentarium for the treatment of DMD.

Duchenne and Becker muscular dystrophy in adolescents: current perspectives

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are life-limiting and progressive neuromuscular conditions with significant comorbidities, many of which manifest during adolescence. BMD is a milder presentation of the condition and much less prevalent than DMD, making it less represented in the literature, or more severely affected individuals with BMD may be subsumed into the DMD population using clinical cutoffs. Numerous consensus documents have been published on the clinical management of DMD, the most recent of which was released in 2010. The advent of these clinical management consensus papers, particularly respiratory care, has significantly increased the life span for these individuals, and the adolescent years are now a point of transition into adult lives, rather than a period of end of life. This review outlines the literature on DMD and BMD during adolescence, focusing on clinical presentation during adolescence, impact of living with a chronic illness on adolescents, and the effect that adolescents have on their chronic illness. In addition, we describe the role that palliative-care specialists could have in improving outcomes for these individuals. The increasing proportion of individuals with DMD and BMD living into adulthood underscores the need for more research into interventions and intracacies of adolescence that can improve the social aspects of their lives.

Diagnosis and management of Duchenne muscular dystrophy, part 2: respiratory, cardiac, bone health, and orthopaedic management

A coordinated, multidisciplinary approach to care is essential for optimum management of the primary manifestations and secondary complications of Duchenne muscular dystrophy (DMD). Contemporary care has been shaped by the availability of more sensitive diagnostic techniques and the earlier use of therapeutic interventions, which have the potential to improve patients' duration and quality of life. In part 2 of this update of the DMD care considerations, we present the latest recommendations for respiratory, cardiac, bone health and osteoporosis, and orthopaedic and surgical management for boys and men with DMD. Additionally, we provide guidance on cardiac management for female carriers of a disease-causing mutation. The new care considerations acknowledge the effects of long-term glucocorticoid use on the natural history of DMD, and the need for care guidance across the lifespan as patients live longer. The management of DMD looks set to change substantially as new genetic and molecular therapies become available.

Differences in vertebral morphology around the apical vertebrae between neuromuscular scoliosis and idiopathic scoliosis in skeletally immature patients: a three-dimensional morphometric analysis

Background

Recent morphological analyses of vertebrae in patients with scoliosis have revealed three-dimensional (3D) deformities in the vertebral bodies. However, it remains controversial whether these deformities are secondary changes caused by asymmetrical vertebral loading or primary changes caused by aberrant asymmetrical vertebral growth. Furthermore, the difference in vertebral morphology between scoliosis with different pathogeneses remains unclear. This study was aimed to investigate the difference in the coronal asymmetry of vertebral bodies between neuromuscular scoliosis (NS) in Duchenne muscular dystrophy (DMD) and idiopathic scoliosis (IS) using in vivo 3D analysis.

Methods

Twelve male skeletally immature patients with NS in DMD and 13 female skeletally immature patients with IS who underwent corrective fusion at our institution were included retrospectively. 3D bone models of the apical and adjacent upper and lower vertebrae in the major curve in the NS patients and in the main and compensatory curves in the IS patients were constructed using an image processing workstation. The heights of the concave and convex sides of the vertebral bodies were measured at the anterior, middle, and posterior and the concave-to-convex vertebral height ratios (VHR) were calculated.

Results

The mean VHRs (anterior/middle/posterior) for the main curve for IS (0.897 ± 0.072/0.832 ± 0.086/0.883 ± 0.059) were significantly smaller than those for NS (0.970 ± 0.048/0.934 ± 0.081/0.958 ± 0.043) in all three parts (p < 0.001). Those of the compensatory curve in IS (0.968 ± 0.045/0.942 ± 0.067/0.967 ± 0.046) did not differ significantly from the NS values in any part.

Conclusions

When compared to the wedging of the vertebral bodies around apical vertebrae in the major curve in NS, which was caused by asymmetric loading, the wedge deformities in both the main and compensatory curves in IS were more severe than would be expected. Our results indicated that morphometric characteristics of vertebral bodies differed according to the pathogenesis of scoliosis and that the pathology of the wedging of vertebral bodies in IS could not be a result only of asymmetric loading to the vertebral bodies.