Comparison of survival analysis between surgical and non-surgical treatments in Duchenne muscular dystrophy scoliosis

Respiratory comorbidities and treatments in Duchenne muscular dystrophy: impact on life expectancy and causes of death

BACKGROUND

Duchenne muscular dystrophy (DMD) is a neuromuscular disorder with progressive decline of pulmonary function increasing the risk of early mortality. The aim of this study was to explore the respiratory-related comorbidities, and the effect of these comorbidities and treatments on life expectancy and causes of death.

METHODS

All male patients living in Sweden with DMD, born and deceased 1970-2019, were included. Data regarding causes of death were collected from the Cause of Death Registry and cross-checked with the medical records along with diagnostics and relevant clinical features.

RESULTS

Hundred and twenty nine patients were included with a median lifespan of 24.3 years. Acute respiratory failure accounted for 63.3% of respiratory-related causes of death. 70.1% suffered at least one pneumonia, with first episode at a median age of 17.8 years. Hypoventilation was found in 73.0% with onset at 18.1 years. 60.5% had their first pneumonia before established hypoventilation. Age at onset of hypoventilation showed a strong correlation with age at first pneumonia. First pneumonia and scoliosis non-treated with scoliosis surgery increased the risk of dying of respiratory-related causes. In 10% of the patients, first pneumonia resulted in acute tracheostomy or early death. Patients treated with assisted ventilation had higher life expectancy compared to untreated patients.

CONCLUSIONS

Our results highlight the importance of identifying subclinical hypoventilation in a timely manner and the importance of an active treatment regime upon clinical signs of pneumonia.

Impact of sagittal and coronal pelvic tilt on hip subluxation in non-ambulatory flaccid neuromuscular scoliosis patients following spinal correction

PURPOSE

To evaluate the actual change in clinical hip pain and hip migration after operation for non-ambulatory flaccid neuromuscular (NM) scoliosis and investigate whether there is an association between hip migration and coronal/sagittal pelvic tilt (CO-PT/SA-PT).

PATIENTS AND METHODS

This retrospective, single-center, observational study evaluated a total of 134 patients with non-ambulatory flaccid neuromuscular scoliosis who underwent surgery performed by a single surgeon between 2003 and 2020, with at least 2 years of follow-up period. Operation procedures were conducted in two stages, beginning with L5-S1 anterior release followed by posterior fixation. Radiologic parameters were measured at preoperative, immediate postoperative, and last follow-up periods with clinical hip pain and clinical hip dislocation events.

RESULTS

The significant improvements occurred in various parameters after correction surgery for NM scoliosis, containing Cobb's angle of major curve and CO-PT. However, Reimer's hip migration percentage (RMP) was increased on both side of hip (High side, 0.23 ± 0.16 to 0.28 ± 0.21; Low side, 0.20 ± 0.14 to 0.23 ± 0.18). Hip pain and dislocation events were also increased (Visual analog scale score, 2.5 ± 2.3 to 3.6 ± 2.6, P value < 0.05; dislocation, 6-12). Logistic regression analysis of the interactions between ΔRMP(High) and the change of sagittal pelvic tilt (ΔSA-PT) after correction reveals a significant negative association. (95% CI 1.003-1.045, P value = 0.0226).

CONCLUSIONS

In cases of non-ambulatory flaccid NM scoliosis, clinical hip pain, and subluxation continued to deteriorate even after correction of CO-PT. There was a relationship between the decrease in SA-PT, and an increase in hip migration percentage on high side, indicating the aggravation of hip subluxation.

Fusion to the sacrum or pelvis increases survival in patients with Duchenne muscular dystrophy

This commentary is on the original article by Arshad and Tsirikos on pages 187–194 of this issue.

Survival of patients with Duchenne muscular dystrophy who underwent spinal deformity correction

AIM

We investigated survival rates after scoliosis correction in individuals with Duchenne muscular dystrophy (DMD) and evaluated factors that can affect them.

METHOD

This was a retrospective cohort study from 2000 to 2022 with a minimum 2-year postoperative follow-up. We reviewed the hospital records/spinal radiographs and analysed data with XLSTAT. Kaplan-Meier and multivariate Cox regression survival analysis was performed.

RESULTS

Forty-three patients had a mean age at surgery of 14 years 5 months. Mean postoperative follow-up was 10 years 10 months. There was no operative or 30-day postoperative mortality in this group. Twenty-four patients died because of cardiorespiratory failure. Median survivorship was 14 years 2 months, with the longest observed survival being 22 years 6 months given the limitation of the length of postoperative follow-up. The degree of preoperative coronal imbalance and pelvic obliquity, as well as intraoperative blood loss, were factors that significantly affected survival. The impact of preoperative sagittal imbalance and extension of the fusion to the sacrum/pelvis trended towards significance. In contrast, age at surgery, preoperative/postoperative scoliosis, thoracic kyphosis, lumbar lordosis, scoliosis and pelvic obliquity flexibility or correction indices, postoperative coronal/sagittal balance, need of preoperative non-invasive ventilation, preoperative feeding disorders, development of surgical complications, and length of hospital and intensive care unit stay were exposure variables that did not affect postsurgical survival in patients with DMD.

INTERPRETATION

Survival of up to two decades or more was possible among young patients with DMD after scoliosis correction. This was affected by factors that related to disease and deformity severity, as well as surgical morbidity.

WHAT THIS PAPER ADDS

There was no operative or 30-day postoperative mortality in this group of patients with Duchenne muscular dystrophy (DMD) undergoing scoliosis correction. Survival probabilities at 5-year, 10-year, 15-year, and 20-year intervals post-surgery were 92%, 80%, 33%, and 12% respectively. Scoliosis surgery achieved good deformity correction and a balanced spine that was maintained at follow-up. Respiratory failure, severe pneumonia, and left ventricular failure were the leading causes of death in the study participants. Preoperative global coronal imbalance, pelvic obliquity, and intraoperative blood loss significantly predicted survival. Factors that affected survival after scoliosis surgery were associated with perioperative morbidity and disease or deformity severity in the DMD group.

Mortality and Causes of Death in Children With Cerebral Palsy With Scoliosis Treated With and Without Surgery

BACKGROUND AND OBJECTIVES

To compare mortality and causes of death in scoliotic children with cerebral palsy (CP) with and without scoliosis surgery.

METHODS

National population-based registries were searched for children with CP and scoliosis with and without surgery for scoliosis and were analyzed for comorbidities, mortality, and causes of death.

RESULTS

Two hundred thirty-six had not been operated and 238 had been operated on for scoliosis during the median follow-up of 17.8 (interquartile range [IQR] 11.7-25.7) and 23.0 (IQR 18.4-28.2) years, respectively. Both groups had similar comorbidities. During the follow-up, mortality was higher in the nonsurgically treated group than in the surgically treated group (n = 38/236, 16% and 8.7 per 1,000 follow-up years vs n = 29/238, 12% and 5.3 per 1,000 follow-up years, p = 0.047). In patients with nonsurgical treatment, the cause of death was respiratory in 76.3% (29/38) and 37.9% (11/29) in patients with surgical treatment of scoliosis (6.6 and 2.0 per 1,000 follow-up years, p = 0.002). Neurologic causes of death were more common in surgically treated patients than in nonsurgically treated patients, 44.8% (13/29) and 15.8% (6/38), respectively (3.0 and 1.1 per 1,000 follow-up years, p = 0.009).

DISCUSSION

Surgical treatment of scoliosis associates to reduced mortality because of respiratory causes in children with CP and scoliosis.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence of the effects of spinal fusion on mortality of children with severe scoliosis due to CP.

Long-term Observation in Patients with Duchenne Muscular Dystrophy with Early Introduction of a Standing Program Using Knee-ankle-foot Orthoses

Objectives

This study investigated the outcomes of the early introduction of a standing program for patients with Duchenne muscular dystrophy (DMD).

Methods

This was a retrospective observational study of 41 outpatients with DMD aged 15-20 years. We introduced the standing program using knee-ankle-foot orthoses (KAFO) to slow the progression of scoliosis when ankle dorsiflexion became less than 0° in the ambulatory period.

Results

Thirty-two patients with DMD were offered the standing program with KAFO; 12 continued the program until the age of 15 years (complete group) and 20 discontinued the program before the age of 15 years (incomplete group). The non-standing program group included 9 patients. The standing program with KAFO was significantly associated with the Cobb angle at the age of 15 years after adjustment for the duration of corticosteroid use and DMD mutation type (P=0.0004). At the age of 15 years, significant correlations were found between the ankle dorsiflexion range of motion (ROM) and non-ambulatory period (P=0.0010), non-ambulatory period and Cobb angle (P<0.0001), Cobb angle and percent predicted forced vital capacity (P=0.0004), and ankle dorsiflexion ROM and Cobb angle (P=0.0066). In the complete group, the age at ambulation loss (log-rank P=0.0015), scoliosis progression (log-rank P=0.0032), and pulmonary dysfunction (log-rank P=0.0006) were significantly higher than in the non-standing program group.

Conclusions

The early introduction of a standing program for DMD patients may prolong the ambulation period and slow the progression of scoliosis and pulmonary dysfunction.

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.

Surgical and long-term functional outcomes of patients with Duchenne muscular dystrophy following spinal deformity correction

BACKGROUND

Life expectancy in patients with Duchenne muscular dystrophy (DMD) has improved due to advances in medical care. DMD patients develop progressive spinal deformity after loss of ambulatory function and onset of wheelchair dependence for mobility. There is limited published data on the effect of spinal deformity correction on long-term functional outcomes, quality of life (QoL), and satisfaction in DMD patients.

AIM

To investigate the long-term functional outcomes following spinal deformity correction in DMD patients.

METHODS

This was a retrospective cohort study from 2000-2022. Data was collected from hospital records and radiographs. At follow-up, patients completed the muscular dystrophy spine questionnaire (MDSQ). Statistical analysis was performed by linear regression analysis and ANOVA to analyse clinical and radiographic factors significantly associated with MDSQ scores.

RESULTS

Forty-three patients were included with mean age 14.4 years at surgery. Spino-pelvic fusion was performed in 41.9% of patients. Mean surgical time was 352.1 min and mean blood loss was 36% of estimated total blood volume. Mean hospital stay was 14.1 d. Postoperative complications occurred in 25.6% of patients. Mean preoperative scoliosis was 58°, pelvic obliquity 16.4°, thoracic kyphosis 55.8°, lumbar lordosis 11.1°, coronal balance 3.8 cm, and sagittal balance + 6.1 cm. Mean surgical correction of scoliosis was 79.2% and of pelvic obliquity was 80.8%. Mean follow-up was 10.9 years (range: 2-22.5). Twenty-four patients had died at follow-up. Sixteen patients completed the MDSQ at mean age 25.4 years (range 15.2-37.3). Two patients were bed-ridden and 7 were on ventilatory support. Mean MDSQ total score was 38.1. All 16 patients were satisfied with the results of spinal surgery and would choose surgery again if offered. Most patients (87.5%) reported no severe back pain at follow-up. Factors significantly associated with functional outcomes (MDSQ total score) included greater duration of post-operative follow-up, age, scoliosis postoperatively, correction of scoliosis, increased lumbar lordosis postoperatively, and greater age at loss of independent ambulation.

CONCLUSION

Spinal deformity correction in DMD patients leads to positive long-term effects on QoL and high patient satisfaction. These results support spinal deformity correction to improve long-term QoL in DMD patients.

Selected clinical and demographic factors and all-cause mortality among individuals with Duchenne muscular dystrophy in the Muscular Dystrophy Surveillance, Tracking, and Research Network

Population-based estimates of survival among individuals with Duchenne muscular dystrophy (DMD) living in the United States are lacking. It is also unclear whether the association between glucocorticoid use and all-cause mortality persists in the context of other common treatments (cardiac medication, cough-assist, bilevel positive airway pressure, and scoliosis surgery) observed to delay mortality. Among 526 individuals identified by the Muscular Dystrophy Surveillance, Tracking, and Research Network, the estimated median survival time from birth was 23.7 years. Current glucocorticoid users had a lower hazard of mortality than non-users. Individuals who ever had scoliosis surgery had a lower hazard of mortality than individuals who did not have scoliosis surgery. Individuals who ever used cough assist had a lower hazard of mortality than individuals who never used cough assist. Non-Hispanic Black individuals had a higher hazard of mortality than non-Hispanic White individuals. No differences in hazards of mortality were observed between ever versus never use of cardiac medication and ever versus never use of bilevel positive airway pressure. The glucocorticoid observation is consistent with the 2018 Care Considerations statement that glucocorticoid use continues in the non-ambulatory phase. Our observations may inform the clinical care of individuals living with DMD.

FRONTAL AND SAGITTAL PATTERNS OF NEUROMUSCULAR SPINAL DEFORMITIES BASED ON NOSOLOGICAL PROFILE

ABSTRACT Objective: Reveal frontal and sagittal patterns of spinal deformity depending on neuromuscular nosology for surgery and outcome planning. The characteristics of spinal deformity vary according to the pathology. In cerebral palsy, muscular dystrophies, and spinal muscular atrophy, specific features of deformities are poorly written, especially in the sagittal profile. Methods: The evaluation criteria were age, gender of the patients, the volume of blood loss, duration of hospitalization, measurement of the deformity curve, thoracic and lumbar kyphosis (Cobb angle), pelvic obliquity concerning the horizontal line, the percentage of curve correction. Cobb angle was measured preoperatively before hospital discharge (up to 21 days postoperatively) and one year after surgery. Results: The cohort of 71 patients with spinal deformities due to neuromuscular diseases included four groups: muscular dystrophy (MD), spinal muscular atrophy (SMA), Duchenne muscular dystrophy (DMD), and cerebral palsy (CP). The most characteristic deformity in the frontal plane was C-shaped thoracolumbar scoliosis with rotation of the pelvis; rotation of the vertebrae increased according to the magnitude of scoliosis. Lumbar hyperlordosis was common in patients with PD, whereas decreased thoracic kyphosis or even thoracic lordosis occurs more frequently in patients with DMD. Moderate correction of scoliosis was observed in all groups. There was no significant improvement in functional status, according to the FIM. Conclusion: The findings showed that rigid hyperlordosis is the main problem of spinal deformities in neuromuscular patients. Scoliosis and pelvic obliquity can be well corrected in NMS by pedicle screw construction with standard maneuvers and pelvic screw fixation. Level of Evidence IV; Lesser quality prospective study.