Impact of a Comparative Study on the Management of Scoliosis in Duchenne Muscular Dystrophy: Are Corticosteroids Decreasing the Rate of Scoliosis Surgery in the United States?

A population-based study of scoliosis among males diagnosed with a dystrophinopathy identified by the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet)

INTRODUCTION/AIMS

Scoliosis is a common comorbidity among individuals diagnosed with a dystrophinopathy. We examined associations between clinical predictors and scoliosis in childhood-onset dystrophinopathy.

METHODS

The progression and treatment of scoliosis were obtained from data collected by the US population-based Muscular Dystrophy Surveillance, Tracking, and Research Network. Associations between loss of independent ambulation (LoA) and corticosteroid use and scoliosis outcomes (ages at or exceeding Cobb angle thresholds [10°, 20°, 30°]; surgery) were estimated using Kaplan-Meier curve estimation and extended Cox regression modeling.

RESULTS

We analyzed curvature data for 513 of 1054 individuals ascertained. Overall, approximately one-half had at least one radiograph and one-quarter had a curvature of at least 20°. The average maximum curvature was 25.0° (SD = 21.5°) among all individuals and 42.8° (SD = 18.8°) among those recommended for surgery. Higher adjusted hazards ratio of curvature (aHR(curvature) [95% confidence interval]) were found among individuals with LoA compared to those without LoA (aHR(10)  = 6.2 [4.4, 8.7], aHR(20)  = 15.3 [7.4, 31.7], aHR(30)  = 31.6 [7.7, 128.9]), among individuals who did not use corticosteroids compared to those who did (aHR(10)  = 1.2 [0.9, 1.7], aHR(20)  = 1.8 [1.1, 2.7], aHR(30)  = 2.3 [1.3, 4.0]), and among non-ambulatory individuals who used corticosteroids after LoA compared to those who did not (aHR(10)  = 1.8 [1.2, 2.8], aHR(20)  = 1.6 [1.0, 2.6], aHR(30)  = 3.6 [1.6, 7.9]). Scoliosis surgery among individuals with LoA who did not use corticosteroids was more than double compared to those who used (aHR = 2.3 [1.3, 4.2]).

DISCUSSION

Our retrospective observational study suggests corticosteroids may delay spinal curvature progression and need for scoliosis surgery. Continuing corticosteroids after LoA also showed potential benefits of delaying curvature progression, additional studies are needed to confirm this finding or address the magnitude of benefit.

The clinical course of Duchenne muscular dystrophy in the corticosteroid treatment era: a systematic literature review

Background

Duchenne muscular dystrophy (DMD) is a severe rare progressive inherited neuromuscular disorder, leading to loss of ambulation (LOA) and premature mortality. The standard of care for patients with DMD has been treatment with corticosteroids for the past decade; however a synthesis of contemporary data describing the clinical course of DMD is lacking. The objective was to summarize age at key clinical milestones (loss of ambulation, scoliosis, ventilation, cardiomyopathy, and mortality) in the corticosteroid-treatment-era.

Methods

A systematic review was conducted using MEDLINE and EMBASE. The percentage experiencing key clinical milestones, and the mean or median age at those milestones, was synthesized from studies from North American populations, published between 2007 and 2018.

Results

From 5637 abstracts, 29 studies were included. Estimates of the percentage experiencing key clinical milestones, and age at those milestones, showed heterogeneity. Up to 30% of patients lost ambulation by age 10 years, and up to 90% by 15 years of age. The mean age at scoliosis onset was approximately 14 years. Ventilatory support began from 15 to 18 years, and up to half of patients required ventilation by 20 years of age. Registry-based estimates suggest that 70% had evidence of cardiomyopathy by 15 years and almost all by 20 years of age. Finally, mortality rates up to 16% by age 20 years were reported; among those surviving to adulthood mortality was up to 60% by age 30 years.

Conclusions

Contemporary natural history studies from North America report that LOA on average occurs in the early teens, need for ventilation and cardiomyopathy in the late teens, and death in the third or fourth decade of life. Variability in rates may be due to differences in study design, treatment with corticosteroids or other disease-modifying agents, variations in clinical practices, and dystrophin mutations. Despite challenges in synthesizing estimates, these findings help characterize disease progression among contemporary North American DMD patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01862-w.

Efficacy of corticosteroid in decreasing scoliosis and extending time to loss of ambulation in a single clinic: an effectiveness trial

PURPOSE

Pharmacologic doses of corticosteroid (CS) have been shown to ameliorate the progression of Duchenne muscular dystrophy (DMD) preserving strength, pulmonary function and ambulation as well as reducing the incidence of scoliosis. However, there are serious side effects of CS, which may impact dose tolerance. The purpose of this study was to compare the magnitude of positive CS effects on patients in our clinic to those reported in the literature.

METHODS

We retrospectively reviewed medical records and radiographs of 142 DMD patients who were seen between 1st January 1991 and 31st December 2017.

RESULTS

In total, 101 boys met study inclusion criteria. Of these 32 were steroid naïve, 37 took the recommended dose (standard of care, SOC) of Prednisone or Deflazacort, and 32 took a lower dose (LD). Following initiation of CS, both treatment groups showed an increase in weight velocity and decrease in linear growth velocity. Although there was a trend to later loss of ambulation (LOA) in the SOC group relative to the naïve group by one year, this was not significant, however, a small subgroup of boys on Deflazacort showed a 3.4 year later LOA than the naïve group. The incidence of scoliosis was reduced from 69% in the naïve, to 41% in the LD and 47% in the SOC group.

CONCLUSIONS

Although there was a reduction in the incidence of scoliosis, it was not as robust as seen elsewhere. Many published studies have inadequate data on scoliosis probably due to the lack of inclusion of orthopaedists in the study group.

LEVEL OF EVIDENCE

IV.

Management of Adrenal Insufficiency Risk After Long-term Systemic Glucocorticoid Therapy in Duchenne Muscular Dystrophy: Clinical Practice Recommendations

Long-term glucocorticoid therapy has improved outcomes in patients with Duchenne muscular dystrophy. However, the recommended glucocorticoid dosage suppresses the hypothalamic-pituitary-adrenal axis, leading to adrenal insufficiency that may develop during severe illness, trauma or surgery, and after discontinuation of glucocorticoid therapy. The purpose of this review is to highlight the risk of adrenal insufficiency in this patient population, and provide practical recommendations for management of adrenal insufficiency, glucocorticoid withdrawal, and adrenal function testing. Strategies to increase awareness among patients, families, and health care providers are also discussed.

Trends in spinal deformity surgery in Marfan syndrome

STUDY DESIGN

Analysis of a national database.

OBJECTIVE

To analyze trends in fusion surgery for spinal deformity in Marfan syndrome (MFS) patients, compare patients with and without Marfan, and evaluate differences in surgical approaches.

SUMMARY OF BACKGROUND DATA

National trends of fusion surgery for spinal deformities in MFS patients are not known. Given the rarity of MFS and the nuanced differences in the spinal deformity it causes, it is important to explore differences in fusion surgery between spinal deformity patients with and without MFS.

METHODS

We identified 314 patients (1,410 weighted) with a diagnosis of MFS and spinal deformity who underwent spinal fusion between the years 2003 and 2014. Our primary outcome was national trends in the use of posterior (PSF), anterior-posterior (APSF), and anterior (ASF) spinal fusions. We also compared perioperative complications, mortality rate, length of stay, and hospital charges in a propensity score matched sample of spinal fusion patients with and without a diagnosis of MFS.

RESULTS

The proportion of PSF surgeries increased significantly (p<.01) from 66.7% in 2003 to 92.0% in 2014. MFS patients were more likely to have higher neurologic (2.4% vs. 0.79%, p=.01) complications. There was a significant association between age and approach (p<.01). PSF had a mean age of 20.2, whereas APSF and ASF had mean ages of 27.1 and 35.2, respectively. Approximately 62% of cervical fusions used ASF.

CONCLUSIONS

Our study provides findings from the largest sample analyzed to date and is the only thus far that investigates national trends. Our results are largely consistent with those of other works in that MFS patients undergoing spinal fusion surgery have higher neurologic complications. We also report that surgical treatment has shifted toward a posterior approach. Our findings can give surgeons a better understanding of the postoperative complications and changing national trends in spinal fusion surgery for patients with MFS.

National Trends in Spinal Fusion Surgery for Neurofibromatosis

STUDY DESIGN

Analysis of a national database.

OBJECTIVE

To analyze trends in spinal fusion surgery for neurofibromatosis type I (NF-1) patients and to compare the surgical approaches.

SUMMARY OF BACKGROUND DATA

The preferred surgical approach for fusion treatment of spinal deformity in NF is not well established.

METHODS

We identified 548 patients with a diagnosis of NF-1 who had received spinal fusion surgery between 2003 and 2014. We compared posterior spinal fusion (PSF), anterior-posterior spinal fusion (APSF), and anterior spinal fusion with respect to patient demographics, institutional characteristics, in-hospital complications, and hospitalization lengths and costs. Significance was set at a value of p less than .05.

RESULTS

The number of spinal fusions for NF-1 significantly increased (p = .02) over the study period. The rate of PSF surgeries increased 2.9-fold, whereas the rate of APSF surgeries decreased 2.2-fold. There was also a significant association between the location of the fusion and surgical approach (p<.01), with 66% of ASF cases being cervical spine cases. Compared with patients undergoing PSF and ASF, patients undergoing APSF were significantly younger (p<.01) and had significantly higher hospitalization lengths and costs (p<.01). APSF costs were $180,714 as compared to $144,027 for PSF and $105,312 for ASF.

CONCLUSIONS

There have been significant increases in the rate of spinal fusion surgeries for NF-1 patients. Surgical treatment has shifted over the years and is dependent on the location of the deformity. Patients undergoing APSF are significantly younger.

LEVEL OF EVIDENCE

Level III.