Scoliosis and lung function in spinal muscular atrophy

Secondary outcomes of scoliosis surgery in disease-modifying treatment-naïve patients with spinal muscular atrophy type 2 and nonambulant type 3

INTRODUCTION/AIMS

Available studies on scoliosis surgery in spinal muscular atrophy (SMA) have focused on the primary outcome of the procedure-the correction of the curve-whereas research focusing on secondary outcomes is scarce. We aimed to investigate postsurgical changes in respiratory function, motor function, weight, pain, and satisfaction.

METHODS

We retrospectively reviewed the clinical notes of 32 disease-modifying treatment-naïve patients (26 SMA2, 6 nonambulant SMA3). We also performed investigator-developed phone interviews and conducted a focus group with families on postsurgical satisfaction.

RESULTS

Mean annual rate of forced vital capacity percent decline improved in SMA2: -3.2% postsurgery versus -6.9% presurgery (p < .001), with similar trajectories in SMA3. Gross motor functional scores (Hammersmith Functional Motor Scale) available in 12/32 dropped immediately after surgery: median loss of 6.5 points, with relatively spared upper limb function. Weight z-scores postsurgery dropped in 16/32, requiring food supplements (5/16); one/16 lost >5% of total weight requiring gastrostomy. Postsurgical pain was frequently reported, especially hip pain (13/32). Overall, 10/10 patients/parents participating in the phone interview rated the procedure as very successful for posture and physical appearance. Nonetheless, 7/10 reported postsurgical pain, reduced mobility, and unmet care needs. The seven patients/parents attending the focus group highlighted lack of intensive physiotherapy programs, occupational therapy assistance, and psychological support as postsurgical unmet care needs.

DISCUSSION

This study reports a positive impact of scoliosis surgery on respiratory function and overall satisfaction with posture and physical appearance. The observed negative impact on the other outcomes highlights the importance of multidisciplinary approaches to improve postoperative management.

The effect of scoliosis surgery on pulmonary function in spinal muscular atrophy patients: review of the literature and a meta-analysis

PURPOSE

To determine the effect of surgical instrumentation on pulmonary function after surgery.

METHODS

A literature review was performed to identify articles reporting on the effect of scoliosis surgery on the pulmonary function in patients with spinal muscular atrophy (SMA). Data for each patient were extracted from included studies, and a meta-analysis was performed using the values of forced vital capacity (FVC) before and after surgery.

RESULTS

A total of 127 articles were reviewed, and ten articles were selected for data extraction according to inclusion criteria. The results of the meta-analysis showed no difference in respiratory function pre-operatively and at last follow-up. Four out of ten studies demonstrated similar results and five studies reported a decrease in pulmonary function after surgery. Only one study showed improvement in lung function.

CONCLUSION

At the moment, there is insufficient evidence in the literature to support that spinal surgery can improve respiratory function. According to our meta-analysis study, vital capacity remains either unchanged or the rate of deterioration is decreased after surgery. Nevertheless, these are both considered favorable outcomes taking into account the natural course of the disease with progressive deterioration of pulmonary function over time.

Scoliosis in Spinal Muscular Atrophy Type 1 in the Nusinersen Era

Background and Objectives

The introduction of spinal muscular dystrophy (SMA)-modifying therapies, such as antisense oligonucleotide therapy, has changed the natural history of SMA. Most reports on treatment outcomes have focused on motor scores and respiratory function. The objective of this study is to document the development and progression of scoliosis in patients with SMA1 treated with nusinersen.

Methods

A descriptive single-center study was conducted in patients with SMA1 who were treated with nusinersen before 6 months of age. Data were collected on patients who met criteria, including age at the first nusinersen dose, number of nusinersen doses, degree of scoliosis, respiratory parameters, feeding route, and motor scores at baseline and follow-up. The Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) was subanalyzed using axial (AxS) and appendicular motor (ApS) scores to evaluate a possible correlation between scoliosis and axial muscle strength.

Results

From our cohort, 31 percent (11/35) of patients had a diagnosis of SMA1. Sixty-three percent (7/11) met the inclusion criteria. All patients (7/7) showed initial improvement in their CHOP-INTEND scores in correlation with improvement on the ApS. Despite this, most patients did not show improvement in the AxS. Subsequently, all patients developed scoliosis in the first year of life with Cobb angles that ranged between 18° and 60°. Furthermore, total CHOP-INTEND scores had dropped in 2 patients alongside the development of a Cobb angle of >40°.

Discussion

Despite the significant improvement in functional motor assessment in patients with SMA1, there is a progression of significant scoliosis despite treatment. Subsequently, lack or minimal improvement on the axial CHOP-INTEND scores may predict worsening on the total motor scores.

Short-term effect and effect on rate of lung function decline after surgery for neuromuscular or syndromic scoliosis

INTRODUCTION

Understanding the impact of scoliosis surgery on lung function is important for counseling patients about risks and benefits of surgery. We prospectively compared the trends in lung function test (LFT) results before and after scoliosis surgery in children with neuromuscular diseases or dysmorphic syndromes. We hypothesized a stabilization.

METHODS

We prospectively included children with neuromuscular or syndromic scoliosis able to perform LFTs. We studied (forced) vital capacity ([F]VC), ratio of forced expiratory volume in 1 s (FEV₁ ) and FVC, and peak expiratory flow (PEF). Preoperative LFT results were compared with results 3-4 months after surgery. The mean monthly change in LFT results up to 2 years after surgery was compared with the preoperative natural history using linear mixed-effects models.

RESULTS

We included 43 patients. No significant change was observed in absolute values of (F)VC, FEV₁ /FVC, and PEF before and after surgery. In 23 neuromuscular patients median standardized VC, FVC, and PEF decreased significantly after surgery from 43% to 33%, 42% to 31%, and 51% to 40%, respectively. In 20 syndromic patients, median FVC decreased from 68% to 65%. The monthly rate of change in FVC did not change significantly in both groups with a mean difference of 0.18% (95% CI: -0.27, -0.61) and -0.44% (95% CI: -1.05, 0.16).

CONCLUSION

No stabilization of lung function 3-4 months after scoliosis surgery was observed in children with neuromuscular and syndromic scoliosis with restrictive lung function disease. The effect on the rate of lung function decline remains inconclusive.

Protocol-driven early tracheal extubation in patients with flaccid neuromuscular scoliosis and pre-existing lung disease

PURPOSE

To review the results of a postoperative respiratory pathway for patients with muscular dystrophy (MD) and spinal muscular atrophy (SMA) undergoing spinal surgery.

METHODS

With IRB approval, a retrospective review was done on all patients with SMA and MD undergoing spinal surgery on a neuromuscular protocol. Baseline demographics, perioperative results, and long-term outcomes were collected. Per the protocol, patients remained intubated after surgery and were transported to the intensive care unit (ICU) for extubation. We present the results of protocol implementation and compare patients with MD to those with SMA.

RESULTS

Twenty-four patients were treated using the protocol. Average age was 13.1 years. Severe restrictive lung disease was present in 75% of patients. Nocturnal BiPAP was required in 68% of patients. Average number of instrumented levels was 17. All patients were immediately extubated upon entering the ICU. There were three respiratory complications and only was patient was re-intubated. Average ICU stay was 1.8 days and average hospital length of stay was 6.7 days. No differences in postoperative inspiratory or expiratory positive airway pressures were observed between the MD and SMA groups.

CONCLUSION

Through a multidisciplinary neuromuscular protocol, excellent clinical outcomes were achieved in patients with neuromuscular scoliosis and restrictive lung disease, with complication rates and length of stay significantly lower than previously published data.

LEVEL OF EVIDENCE

IV.

Nonrespiratory complications of nusinersen-treated spinal muscular atrophy type 1 patients

BACKGROUND

Emergence of new treatments for spinal muscular atrophy type 1 (SMA1) has led to dramatic improvements in respiratory failure and survival. However, these "treated" patients sustain major problems in other organ systems, which may directly or indirectly affect their respiratory function. We observed three main nonrespiratory manifestations in these patients comprised of facial deformities, feeding problems, and spinal deformities.

OBJECTIVE

To investigate these three main sequelae in nusinersen-treated SMA1 patients.

METHODS

Data on nusinersen-treated SMA1 patients were prospectively collected throughout a 3-year period, with special focus upon nonrespiratory features of the disease.

RESULTS

Twenty nusinersen-treated SMA1 patients were included (eight males, median age 13.5 months, interquartile range: 4-56.2 months), among whom 17 survived after 3 years of follow-up. At follow-up, 15 (88%) patients were diagnosed with facial weakness, hypoplasia, or deformity. All but one patient (94%) were fed invasively by percutaneous endoscopic gastrostomy or nasogastric tube feeding. Four patients (25%) had maintained oral feeding in parallel to gastrostomy feeding and had clinical and radiologic evidence of aspirations. Fifteen (88%) patients were diagnosed with scoliosis, of whom seven had undergone or were scheduled to undergo corrective surgery.

CONCLUSIONS

Nusinersen-treated SMA1 patients may sustain facial deformities, feeding problems, and severe scoliosis, all of which affect their respiratory system. Strict surveillance of these complications is essential to avoid further respiratory morbidity.

Minimally Invasive Fusionless Surgery for Scoliosis in Spinal Muscular Atrophy: Long-term Follow-up Results in a Series of 59 Patients

BACKGROUND

Treatment of spinal muscular atrophy (SMA) scoliosis has evolved in the last decade, with the emergence of fusionless surgical techniques that allow correction of the deformity before the end of growth spurt. These techniques are expected to delay definitive spine fusion and preserve trunk growth.

PURPOSE

The aim was to evaluate long-term clinical, radiologic, and respiratory outcomes of a minimally invasive fusionless surgery (MIFLS) in SMA scoliosis.

METHODS

All children affected with SMA scoliosis who underwent MIFLS in our department from 2011 to 2019 were included. The instrumentation consisted in a bilateral sliding rod construct from T1 to the sacrum, anchored proximally by double-hook claws and distally by iliosacral screws. Clinical, genetic, respiratory and radiographic data were retrospectively reviewed. A patient's satisfaction survey was performed.

RESULTS

A total of 59 children with genetic confirmation of SMA (9SMA1c, 47SMA2, and 3SMA3) underwent MIFLS at a mean age of 11±1.9 years. All of them were nonwalker at the time of surgery. Twenty-six were treated with intrathecal Nusinersen. Mean follow-up was 5.2 years (2 to 9.6 y). Mean major coronal curve improved from 79±15 to 41±16 degrees and pelvic obliquity decreased from 24±11 to 5.9±4 degrees. Mean space available for lung improved from 77% to 93%. Mechanical or infectious complications occurred in 9 patients, with removal of the implant in 1. 6 children required unplanned surgeries. Postoperative bracing was needed in 13 children. Mean gain weight 3 years after the first surgery was 6 kg. 91.5% of patients had a positive satisfaction of the surgery. There was no significant impact in respiratory function postoperatively. Only 30 children required rod lengthening procedures, with a mean interval between procedures of 1.9 years (0.5 to 3.7 y). No arthrodesis was required at last follow-up in any patient.

CONCLUSION

Bipolar MIFLS in SMA preserves spinal and thoracic growth without interference with respiratory function. It provides a significant correction of spinal deformity and pelvic obliquity, having a reduced rate of complications. The correction of spinal deformity was maintained at long term, not requiring definitive fusion at the end of growth.

LEVEL OF EVIDENCE

Level IV.

Sagittal Plane Deformities in Children with SMA2 following Posterior Spinal Instrumentation

This is a retrospective radiographic review to assess post-operative sagittal plane deformities in patients with Spinal Muscular Atrophy type 2 that had been treated with posterior spinal instrumentation. Thirty-two patients with a history of either spinal fusion (N = 20) or growing rods (N = 12) were identified with an average of 7.6 (2.1-16.6) years post-operative follow-up. Forty percent (13/32) of the patients were identified as having obvious "tucked chin" (N = 4), "tipped trunk" (N = 9), or both (N = 3). Sacral incidence was the only parameter that was statistically significant change between pre-operative or immediate post-operative measurements (66.9° vs. 55.2° p = 0.03). However, at final follow-up, the post-operative thoracic kyphosis had decreased over time in those that developed a subsequent sagittal deformity (24.2°) whereas it increased in those that did not (44.7°, p = 0.008). This decrease in thoracic kyphosis throughout the instrumented levels, resulted in a greater lordotic imbalance (30.4° vs. 5.6°, p = 0.001) throughout the instrumented levels in the group that developed the subsequent cervical or pelvic sagittal deformities. In conclusion, sagittal plane deformities commonly develop outside the instrumented levels in children with SMA type 2 following posterior spinal instrumentation and may be the result of lordotic imbalance that occurs through continued anterior growth following posterior instrumentation.

Evolving Surgical Management for Early-Onset Scoliosis in Spinal Muscular Atrophy Type 1 Given Improvements in Survival

CASE

We present a case of an 18-month-old child with early-onset scoliosis in the setting of spinal muscular atrophy (SMA) type 1 whose rapidly progressive scoliosis is successfully managed with magnetic growing rods, the youngest age of implantation in a patient with SMA we are currently aware of. Technical challenges, complications, and outcome are described in this case presentation.

CONCLUSION

Patients with SMA type 1 and early-onset scoliosis can be managed with growing-rod constructs given dramatic improvements in medical care that have expanded life expectancy.

The impact of scoliosis surgery on pulmonary function in spinal muscular atrophy: a systematic review

Scoliosis often occurs coincident with pulmonary function deterioration in spinal muscular atrophy but a causal relationship has not yet been reliably established. A systematic literature review was performed, with pulmonary function testing being the primary outcome pre- and post-scoliosis surgery. Levels of evidence were determined and GRADE recommendations made. Ninety studies were identified with only 14 meeting inclusion criteria. Four studies were level III and the rest were level IV evidence. The average age at surgical intervention was 11.8 years (follow-up 6.1 years). Post-operative pulmonary function progressively declined for the majority of studies. Otherwise, pulmonary function: improved (two studies), were unchanged (two studies), had a decreased rate of decline (three studies), declined initially then returned to baseline (two studies). Respiratory and spine-based complications were common. Given the available evidence, the following GRADE C recommendations were made: (1) surgery is most often associated with decreases in pulmonary function; (2) the impact of surgery on pulmonary function is variable, but does not improve over pre-operative baseline; (3) surgery may result in a decreased rate of decline in pulmonary function post-operatively. Given this lack of evidence-based support, the risk-benefit balance should be taken into consideration when contemplating scoliosis surgery.

Cervical rotation, chest deformity and pelvic obliquity in patients with spinal muscular atrophy

Background

Musculoskeletal disorders are often observed in patients with spinal muscular atrophy (SMA). The aim of the study was to assess passive ranges of rotation in the cervical spine, chest deformity and pelvic obliquity in SMA patients, and to compare these results to the norms obtained in the group of healthy individuals. The second aim was to review these measurements and Cobb angle values for correlations in SMA patients.

Methods

The study included 74 patients with SMA and 89 healthy individuals aged 2 to 18 years. Cervical Rotation (CR), Supine Angle of Trunk Rotation (SATR) and Pelvic Obliquity (PO) tests were carried out.

Results

Cervical rotation ranges were significantly higher in the control group than in SMA patients (p < 0.05). Differences between cervical rotation ranges to the left and to the right were significantly larger in SMA I and SMA II groups than in healthy individuals (p = 0.000). Chest asymmetry and pelvic obliquity were bigger in SMA groups than in the control (p < 0.05). Significant correlations between cervical rotation measurements, chest deformity, pelvic obliquity and Cobb angle were found in SMA individuals, depending on the type.

Conclusions

The results of the study suggest that CR, SATR and PO tests may assist in the assessment of SMA patients in addition to the radiographic evaluation of the spine. Biomechanical relationships between disorders located in various skeletal structures should be taken into account in the treatment of SMA patients. Special attention should be given to assessing postural parameters in non- sitters and sitters. Treatment of patients with SMA and associated musculoskeletal disorders requires a multi-specialist approach.

Predictors for Deformity Progression in a Spinal Muscular Atrophy Cohort After Scoliosis Correction Surgery

STUDY DESIGN

This was a single-center, retrospective study.

OBJECTIVE

The objective of this study was to assess the risk factors for deformity progression after scoliosis correction surgery in spinal muscular atrophy (SMA) patients.

SUMMARY OF BACKGROUND DATA

Moderate residual postoperative scoliosis curve is common in SMA populations; however, the acceptable postoperative scoliosis curve for preventing deformity progression remains uncertain.

MATERIALS AND METHODS

Twenty-nine SMA patients undergoing scoliosis correction surgery were included. Scoliosis progression was defined as an increase of 10 degrees in the major curve of Cobb angle (MCCA); pelvic obliquity (PO) or concave-side hip progression was arbitrarily defined as an increase of ≥1 grade after surgery. Risk factors for deformity progression were examined using Cox proportional hazard models. The cumulative incidence rate of deformity progression was performed by the Kaplan-Meier survival analysis RESULTS:: The mean age at surgery was 13.3 years (range: 8-25 y) and the mean follow-up time was 7 years (range: 2-22.9 y). The mean MCCA was corrected from 69 to 34.6 degrees at initial follow-up and 42.2 degrees at the final follow-up. Postoperative MCCA (P=0.002) and PO (P=0.004) at initial follow-up were the risk factors for scoliosis progression. Postoperative MCCA at initial follow-up (P=0.007) and age at the time of surgery (P=0.017) were the risk factors for PO progression. Different cutoff points of postoperative MCCA at initial follow-up were compared for predicting deformity progression. We found the patient with postoperative MCCA of <30 degrees at initial follow-up had a significantly less cumulative incidence rate of progression than their counterparts for scoliosis (P=0.005), PO (P=0.023), and concave-side hip progressions (P=0.008).

CONCLUSIONS

We recommended that MCCA should be corrected to <30 degrees to prevent postoperative scoliosis, PO, and concave-side femoral head coverage percentage progressions. Patients receiving surgery earlier had less postoperative MCCA at initial follow-up but with no increase in the risk of postoperative scoliosis progression.

Impact of scoliosis surgery on pulmonary function in patients with muscular dystrophies and spinal muscular atrophy

BACKGROUND

Scoliosis is a common complication of severe neuromuscular diseases. The aim of this study is to determine the impact of posterior spinal fusion on pulmonary function parameters in patients with severe neuromuscular disease at our medical center.

METHODS

Retrospective chart review of all patients with severe neuromuscular disease who had posterior spinal fusion between 2012 and 2017 at Texas Children's Hospital. Patients with growing rods, brain injury or malformation, and/or spina bifida were excluded. Pulmonary function measures before and after spinal surgery were determined.

RESULTS

A total of 20 eligible patients were identified, 7 with Duchenne muscular dystrophy, 6 with spinal muscular atrophy, 3 with merosin deficient muscular dystrophy, 2 with Charcot-Marie-Tooth, 1 with central core disease, and 1 with dystroglycanopathy. The mean change in vital capacity from pre- to postspine surgery was a loss of 0.63 L for the spinal muscular atrophy patients, a loss of 0.36 L for the Duchenne muscular dystrophy patients, and a gain of 0.23 L for the merosin deficient patients. The difference between spinal muscular atrophy and merosin deficient patients was statistically significant (P = .02) CONCLUSION: In this single-center retrospective study, we found that after spine surgery for scoliosis, all patients with spinal muscular atrophy and most patients with Duchenne muscular dystrophy lost vital capacity, while the patients with merosin deficient muscular dystrophy gained vital capacity. These differences were not associated with differences is respiratory strength, body mass index, or surgical outcomes.

Lumbar laminotomy for the intrathecal administration of nusinersen for spinal muscular atrophy: technical note and outcomes

Nusinersen (Spinraza) is a US Food and Drug Administration-approved intrathecal medication for the treatment of spinal muscular atrophy (SMA). Adult patients with SMA often undergo thoracolumbar fusion to treat neurogenic scoliosis, preventing thecal access. The authors report a laminotomy technique and the ease of intrathecal access in three SMA patients with prior thoracolumbar fusions.Patients were positioned in the lateral decubitus position or prone. Lumbar laminotomy was performed below the conus, between the lateral longitudinal rods, to preserve mechanical stability. Fluoroscopy provided real-time identification of instruments. Hardware was contoured with a carbide drill bit to develop the surgical window. Fiducial screws were placed along the perimeter for demarcation. Sublaminar wire removal caused dural defects that were repaired with a layer of dural substitute onlay and sealant. All patients successfully received nusinersen thecal injections via lumbar puncture by an interventional radiologist. Fluoroscopy time ranged from 6 to 36 seconds. No postoperative pseudomeningoceles, cerebrospinal fluid leaks, or wound complications occurred.For patients with SMA and posterior fusion from prior scoliosis treatment, lumbar laminotomy is an effective method for creating thecal access for the administration of nusinersen.

Reliability of four tests to assess body posture and the range of selected movements in individuals with spinal muscular atrophy

Background

The majority of individuals with spinal muscular atrophy (SMA) experience progressive skeletal deformities which may affect the quality of life and mobility. To date, no studies have evaluated the reliability of tests assessing body posture and joint mobility in SMA patients. The purpose of this study was to assess the reliability of Cervical Rotation test (CR), Supine Angle of Trunk Rotation test (SATR), Hip Extension test (HE) and Pelvic Obliquity test (PO) developed to evaluate the musculoskeletal system in SMA individuals.

Methods

Thirty individuals (12 girls and 18 boys) aged 4–15 with SMA type II (n = 24) and III (n = 6) confirmed by genetic examinations were qualified for the study. The participants were examined twice by three physiotherapists on the same day. The examination included four tests, i.e. CR, SATR, HE and PO tests aimed at assessing ranges of rotation in the cervical spine, chest deformities, ranges of hip extension and pelvis position while sitting. Statistical calculations were made with the use of statistical software IBM SPSS Statistics version 20. Reliability was assessed using the Intraclass Correlation Coefficient (ICC).

Results

Intraobserver reliability was excellent for CR (ICC range 0.839–0.911), SATR (ICC range 0.918–0.939 - the upper part of the sternum; ICC range 0.951–0.975 - the lower part of the sternum), HE (ICC range 0.988–0,991) and PO (ICC range 0.896–0.935) tests.

The interobserver ICC reached the excellent values in CR (ICC range 0.912–0.920), SATR (ICC = 0.888 - the upper part of the sternum, ICC = 0.951 - the lower part of the sternum), HE (ICC range 0.922–0.923) and PO (ICC = 0.928) tests.

Conclusions

CR, SATR, HE and PO tests are reliable and may be used for examining individuals with SMA. The application of these tests provides a possibility to detect early changes in the musculoskeletal system in children and adolescents and to assess the effectiveness of the implemented pharmacotherapy and rehabilitation.

Outcomes of Primary Posterior Spinal Fusion for Scoliosis in Spinal Muscular Atrophy: Clinical, Radiographic, and Pulmonary Outcomes and Complications

BACKGROUND

Spinal muscular atrophy (SMA) is a progressive neuromuscular disease commonly including progressive scoliosis resulting in severe deformity and negatively affecting pulmonary function. Surgical correction and stabilization of this progressive deformity is generally recommended; however, the timing and method of surgical fixation remains controversial.

METHODS

Retrospective review of clinical, radiographic, and pulmonary function data from 16 children with SMA and surgically treated scoliosis between 1985 and 2013. Radiographic data included direct measures of major curve, coronal balance, pelvic obliquity, T1-T12 height, T1-S1 height, and T1-rod length. Estimations of rib collapse, thoracic cavity shape, and space-available-for-lung (T6:T12, width ratio; T6:T10, rib-vertebral-angle difference ratios; and lung height) were determined. Eleven patients were able to complete pulmonary function testing. Results were compared with published outcomes for growing rod constructs.

RESULTS

Posterior spinal fusion was performed at an average age of 9.8±3.6 years. The mean age at most recent follow-up was 19.4 years (range, 10 to 37 y), with a mean follow-up of 10.1 years (range, 3.1 to 26 y). Radiographic measurements improved from preoperative to latest follow-up as follows: major curve, 78±20 degrees to 27±24 degrees; coronal balance, 4.1±4.0 cm to 1.9±2.2 cm; pelvic obliquity (median), 23 to 5 degrees; T1-T12 height, 19±3 cm to 22±3 cm; T1-S1 height, 31±7 cm to 36±6 cm; T1-rod length, 0.8±1.1 cm (postop) to 2.8±1.6 cm (final); and space-available-for-lung ratio, 0.88±0.26 to 0.95±0.25. Rib collapse continued throughout the follow-up period in all but 1 patient. Pulmonary function testing demonstrated a decrease in rate of decline in forced vital capacity and forced expiratory volume when comparing preoperative with postoperative rates. Mean length of stay was 7.8±4.4 days. Complications included reintubation for low tidal volumes (n=1), pneumonia (n=1), superficial wound breakdown (n=1), and superficial infection (n=1).

CONCLUSIONS

Definitive posterior spinal fusion for treatment of scoliosis associated with SMA is effective at controlling curve progression and pelvic obliquity without negatively impacting the space-available-for-lung ratio, trunk height, or pulmonary function at 10 years follow-up.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Clinical Characteristics of Spinal Muscular Atrophy in Korea Confirmed by Genetic Analysis

The objective of this study was to review the clinical characteristics of patients with spinal muscular atrophy and to emphasize the importance of performing genetic mutational analysis at initial patient assessment. This is a single center oriented, retrospective, and descriptive study conducted in Seoul, South Korea. Genetic mutational analysis to detect the deletion of exon 7 of the SMN1 gene on chromosome 5q13 was performed by multiplex ligation-dependent probe amplification. Clinical features, electrodiagnostic study results, muscle biopsy results, and laboratory test results were reviewed from patient medical records. Of all 28 patients (15 males and 13 females), all showed bilateral symmetric proximal dominant weakness. Among them, 3 patients were classified as type I, 14 patients as type II, and 11 patients as type III. Twenty-five patients had scoliosis and eight of these patients received surgical treatment for scoliosis with improvement in clinical outcomes. Ventilator support was used in 15 patients. In terms of the diagnostic process, 15 patients had completed an electrodiagnostic study and muscle biopsy before genetic testing, and six of these patients were initially misdiagnosed with myopathy. Owing to the similar clinical features of SMA and congenital myopathy, an electrodiagnostic study and muscle biopsy could create confusion in the correct diagnosis in some cases. Therefore, it is recommended that genetic mutation analysis should be conducted along with an electrodiagnostic study or muscle biopsy in the diagnostic process for spinal muscular atrophy.

Management of scoliosis in patients with Duchenne muscular dystrophy and spinal muscular atrophy: A literature review

Scoliosis occurs in nearly all non-ambulatory children with spinal muscular atrophy (SMA) and Duchenne muscular dystrophy (DMD). Non-operative treatments have not been shown to be effective at preventing progression of scoliosis. Progressive scoliosis can impact the ability of patients to sit comfortably, be cosmetically unappealing, and in severe cases exacerbate pulmonary disease. The main goal of operative treatment is to improve sitting balance and prevent progression of scoliosis. Complication rates are high and there is little data on effect of operative treatment on quality of life in children with SMA and DMD. Comprehensive multi-disciplinary pre-operative evaluations are vital to reduce the risks of operative treatment.

Orthopedic Management of Scoliosis by Garches Brace and Spinal Fusion in SMA Type 2 Children

BACKGROUND

Scoliosis is the most debilitating issue in SMA type 2 patients. No evidence confirms the efficacy of Garches braces (GB) to delay definitive spinal fusion.

OBJECTIVE

Compare orthopedic and pulmonary outcomes in children with SMA type 2 function to management.

METHOD

We carried out a monocentric retrospective study on 29 SMA type 2 children who had spinal fusion between 1999 and 2009. Patients were divided in 3 groups: group 1-French patients (12 children) with a preventive use of GB; group 2-French patients (10 children) with use of GB after the beginning of the scoliosis curve; and group 3-Italian patients (7 children) with use of GB after the beginning of the scoliosis curve referred to our centre to perform orthopedic preoperative management.

RESULTS

Mean preoperative and postoperative Cobb angle were significantly lower in the group 1 of proactively braced than in group 2 or 3 (Anova p = 0.03; Kruskal Wallis test p = 0.05). Better surgical results were observed in patients with a minor preoperative Cobb angle (r = 0.92 p <  0.0001). Fewer patients in the group 1 proactively braced required trunk casts and/or halo traction and an additional anterior fusion in comparison with patients in the group 2 and 3. Moreover, major complications tend to be less in the group 1 proactively braced. No significant differences were found between groups in pulmonary outcome measures.

CONCLUSIONS

A proactive orthotic management may improve orthopedic outcome in SMA type 2. Further prospective studies comparing SMA management are needed to confirm these results.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions to Authors on jbjs.org for a complete description of levels of evidence (Retrospective comparative study).

Scoliosis and the impact in neuromuscular disease

Scoliosis can alter respiratory mechanics by changing the orientation of the muscles and joints of the respiratory system and in severe forms can put a patient at risk of severe respiratory morbidity or respiratory failure. However, perhaps the most important factor in determining the pulmonary morbidity in scoliosis is the balance between the "load" or altered respiratory mechanics and the "pump" or the respiratory muscle strength. Therefore, scoliosis in patients with neuromuscular disease will both lead to increased "load" and a weakened "pump", an exceptionally unfortunate combination. While progressive neuromuscular disease by its nature does not respond favorably to attempts to improve respiratory muscle strength, the natural approach of early proactive management of the "load" and in the case of scoliosis a variety of different strategies have been tried with variable short term and long term results. Figuring this out requires both an understanding of the underlying pathophysiology of a particular neuromuscular condition and the available options for and timing of surgical intervention.

Long-term incidence and risk factors for development of spinal deformity following resection of pediatric intramedullary spinal cord tumors

OBJECT

Spinal deformity in pediatric patients with intramedullary spinal cord tumors (IMSCTs) may be either due to neurogenic disability or due to secondary effects of spinal decompression. It is associated with functional decline and impairment in health-related quality-of-life measures. The authors sought to identify the long-term incidence of spinal deformity in individuals who had undergone surgery for IMSCTs as pediatric patients and the risk factors and overall outcomes in this population.

METHODS

Treatment records for pediatric patients (age < 21 years) who underwent surgical treatment for histology-proven primary IMSCTs between 1975 and 2010 were reviewed. All patients were evaluated in consultation with the pediatric orthopedics service. Clinical records were reviewed for baseline and follow-up imaging studies, surgical fusion treatment, and long-term skeletal and disease outcomes.

RESULTS

The authors identified 55 patients (30 males and 25 females) who were treated for pediatric IMSCTs between January 1975 and January 2010. The mean duration of follow-up (± SEM) was 11.4 ± 1.3 years (median 9.3 years, range 0.2-37.2 years). Preoperative skeletal deformity was diagnosed in 11 (20%) of the 55 patients, and new-onset postoperative deformity was noted in 9 (16%). Conservative management with observation or external bracing was sufficient in 8 (40%) of these 20 cases. Surgical fusion was necessary in 11 (55%). Posterior surgical fusion was sufficient in 6 (55%) of these 11 cases, while combined anterior and posterior fusion was undertaken in 5 (45%). Univariate and multivariate analysis of clinical and surgical treatment variables indicated that preoperative kyphoscoliosis (p = 0.0032) and laminectomy/laminoplasty at more than 4 levels (p = 0.05) were independently associated with development of spinal deformity that necessitated surgical fusion. Functional scores and 10-year disease survival outcomes were similar between the 2 groups.

CONCLUSIONS

Long-term follow-up is essential to monitor for delayed development of spinal deformity, and regular surveillance imaging is recommended for patients with underlying deformity. The authors' extended follow-up highlights the risk factors associated with development of spinal deformity in patients treated for pediatric IMSCTs. Surgical fusion allows patients who develop progressive deformity to achieve long-term functional and survival outcomes comparable to those of patients who do not develop progressive deformity.

Longitudinal course of lung function and respiratory muscle strength in spinal muscular atrophy type 2 and 3

BACKGROUND

Spinal muscular atrophy (SMA) is a common genetic disorder that causes severe hypotonia and weakness, and often fatal restrictive lung disease. The aim of the study was to describe the natural history of the respiratory involvement in patients with SMA type 2 and 3 in order to assess the relevance of the clinical classification and identify the parameters associated with the earliest and most rapid decline over time.

METHODS

Thirty-one patients aged 3-21 years were followed over a 10-year period. Lung function, blood gases, respiratory mechanics and muscle strength with recording of oesogastric pressures were measured during routine follow-up.

RESULTS

At least two measurements were available in 16 patients (seven type 2 and nine type 3). Among all the volitional and non-volitional, invasive and non-invasive tests, forced vital capacity (FVC) and sniff nasal inspiratory pressure (SNIP) were shown to be the most informative parameters, showing lower values in SMA type 2, with however a similar rate of decline in patients with SMA type 2 and 3.

CONCLUSION

Our results confirm an earlier decline in lung and respiratory muscle function in patients classified as SMA type 2 as compared with patients classified as type 3. This decline can be assessed by two simple non-invasive tests, FVC and SNIP, with the last maneuver being feasible and reliable in the youngest children, underlying its interest for the monitoring of children with SMA.

Natural course of scoliosis in proximal spinal muscular atrophy type II and IIIa: descriptive clinical study with retrospective data collection of 126 patients

Background

Progressive scoliosis, pelvic obliquity and increasing reduction of pulmonary function are among the most significant problems for patients with SMA type II and SMA type III once they have lost the ability to walk. The aim of this study was to examine and document the development and natural course of scoliosis in patients with spinal muscular atrophy type II and IIIa.

Methods

For the purposes of a descriptive clinical study, we observed 126 patients, 99 with SMA II and 27 with SMA IIIa and the data of scoliosis, pelvic obliquity and relative age-dependent inspiratory vital capacity were evaluated.

Results

Scoliosis and pelvic obliquity were regularly observed already in children under 4 years old in the group with SMA II. The severity and progression of both conditions were much more pronounced in the SMA II group than in the IIIa group. There was already a distinct reduction in relative vital capacity in the group of 4- to 6-year-olds with SMA II.

Conclusions

The differences between the two SMA types II and IIIa described in this study should be taken into consideration when developing new treatments and in management of scoliosis in the childhood years of these patients.

Operative treatment of scoliosis in proximal spinal muscular atrophy: results of 41 patients

INTRODUCTION

The early development of progressive scoliosis with pelvic obliquity is the most significant orthopaedic problem for non-ambulatory children with spinal muscular atrophy (SMA).

PATIENTS

24 SMA patients were operated on for scoliosis using the ISOLA(®) system and 17 patients using a telescopic rod. The average age at spinal surgery was 12.3 years (6.5-22.7) in the ISOLA(®) group and 6.7 years (4.8-10.9) in the telescopic rod group.

RESULTS

The Cobb angle was corrected on average from pre-operative 83°(54°-120°) to post-operative 39°(5°-70°) in the ISOLA(®) group and, respectively, from 62°(28°-86°) to 18°(0°-34°) in the telescopic rod group. Mean loss of correction at mean follow-up of 6 years (3-10) was 6°(0°-33°) in the ISOLA(®) group and at mean follow-up of 8.6 years (3-12) 13°(0°-49°) in the telescopic rod group excluding the patients with rod failure. The vital capacity is not worsened by these operations in comparison to the natural course. After telescopic rods were implanted, there were some unsatisfactory results due to crankshaft phenomenon and an increase of pelvic obliquity.

CONCLUSION

Our recommendation for non-ambulatory SMA patients is to have definitive stabilisation using multisegmental instrumentation, starting from the age of 10 to 12 years.

Bone health and associated metabolic complications in neuromuscular diseases

This article reviews the recent literature regarding bone health as it relates to the patient living with neuromuscular disease (NMD). Studies defining the scope of bone-related disease in NMD are scant. The available evidence is discussed, focusing on abnormal calcium metabolism, increased fracture risk, and the prevalence of both scoliosis and hypovitaminosis D in Duchenne muscular dystrophy, amyotrophic lateral sclerosis, and spinal muscular atrophy. Future directions are discussed, including the urgent need for studies both to determine the nature and extent of poor bone health, and to evaluate the therapeutic effect of available osteoporosis treatments in patients with NMD.

Childhood spinal muscular atrophy: controversies and challenges

Spinal muscular atrophy is an autosomal recessive disorder characterised by degeneration of motor neurons in the spinal cord and is caused by mutations of the survival of motor neuron 1 gene SMN1. The severity of spinal muscular atrophy is highly variable and no cure is available at present. Consensus has been reached on several aspects of care, the availability of which can have a substantial effect on prognosis, but controversies remain. The development of standards of care for children with the disorder and the identification of promising treatment strategies have changed the natural history of spinal muscular atrophy, and the prospects are good for further improvements in function, quality of life, and survival. A long-term benefit for patients will be the development of effective interventions (such as antisense oligonucleotides), some of which are in clinical trials. The need to be prepared for clinical trials has been the impetus for a remarkable and unprecedented cooperation between clinicians, scientists, industry, government, and volunteer organisations on an international scale.

Spinal muscular atrophy: manifestations and management

Spinal muscular atrophy (SMA) is an autosomal recessive disorder caused by a homozygous deletion in the SMN1 gene and is manifested by loss of the anterior horn cells of the spinal cord. Classifications of the disorder are based on age of onset and the patient's level of function. Scoliosis and hip subluxation or dislocation are two musculoskeletal manifestations associated with SMA. Severity of scoliosis correlates with age at presentation. Bracing has been unsuccessful in halting curve progression and may interfere with respiratory effort. Early onset scoliosis associated with SMA has been successfully treated with growing rod constructs, and posterior spinal fusion can be used in older children. Hip subluxations and dislocations are best treated nonsurgically if the patient reports no pain because a high rate of recurrent dislocation has been reported with surgical intervention.

Avaliação dos resultados do tratamento cirúrgico da escoliose na atrofia muscular espinhal tipo 2

OBJETIVO: Avaliar o resultado do tratamento cirúrgico da escoliose em pacientes com atrofia muscular espinhal (AME) tipo 2. MÉTODO: Estudo retrospectivo com 12 pacientes portadores de AME tipo 2 submetidos à artrodese e instrumentação para correção da escoliose com mais de dois anos de seguimento. Foi avaliado o grau e percentual de correção da deformidade e da obliquidade pélvica no pós-operatório e a perda na última avaliação, além das complicações e o impacto do tratamento sobre a função respiratória. RESULTADOS: O seguimento médio foi de 77,5 meses (6,4 anos) ± 58,9 meses (4,9 anos), o ângulo de Cobb pré-operatório médio foi de 76,1° ± 31,7° (35° a 144°) e no pós-operatório de 29,5° ± 23,2° (5° a 90°), com a correção média de 46,6° (61,29%). A obliquidade pélvica média no pré-operatório foi de 15,1° ± 13,3° (variação de 0° a 37°), e no pós-operatório de 8,5° ± 9,9° (variação de 0° a 30°), com uma correção média de 6,5° (43,37%). Cinco pacientes tiveram complicações (41,6%). A Capacidade Ventilatória Forçada (CVF) média pré-operatória foi de 62,9% ± 38,6% (variação de 23,3% a 89%) e de 45,9% ± 25,0% (variação de 15% a 86,2%), na última avaliação. O declínio foi de 17% da capacidade vital, com redução de 2,4% por ano de seguimento. CONCLUSÕES: O tratamento cirúrgico da escoliose em pacientes com AME permite corrigir a obliquidade pélvica e restabelecer o balanço sagital e coronal liberando as mãos para as atividades da vida diária. A função pulmonar foi afetada positivamente pelo tratamento.

Comparison between Operated Muscular Dystrophy and Spinal Muscular Atrophy Patients in terms of Radiological, Pulmonary and Functional Outcomes

STUDY DESIGN

Retrospective comparative study.

PURPOSE

To study and compare the surgical outcomes of muscular dystrophy (MD) and spinal muscle atrophy (SMA).

OVERVIEW OF LITERATURE

There are few reports that have evaluated and compared the surgical outcomes of MD and SMA patients.

METHODS

The patients (n = 35) were divided into two groups: a MD group with 24 patients and a SMA group with 11 patients. The average follow-up period was 21 months. All patients were operated for scoliosis correction using posterior instrumentation and fusion. In the immediate postoperative period, all efforts were made to reduce the pulmonary complications using non-invasive positive pressure ventilation and a coughing assist devices. The patients were evaluated by radiograph in terms of the Cobb's angle, pelvic obliquity, T1 translation, thoracic kyphosis and lumbar lordosis. The pulmonary function and self-image satisfaction were also assessed.

RESULTS

There was a lower correction rate in the MD group (41.5%) than in the SMA group (48.3%), even though the curves were smaller in the MD group. The correction in the pelvic obliquity was significantly better in the SMA group (p = 0.03). The predicted vital capacity showed a 4% reduction in the MD group 1 year after surgery, while the SMA group showed a 10% reduction. The peak cough flow and end tidal PCO(2) did not deteriorate and were well maintained. The average score for the improvement in self-image satisfaction postoperatively was 3.96 and 4.64 for the MD and SMA groups, respectively. The total complication rate was 45.7%; 14.3% of which were respiratory-related.

CONCLUSIONS

Surgical intervention for MD and SMA may be performed safely in patients with a very low forced vital capacity (< 30%) through aggressive preoperative and postoperative rehabilitation efforts.

[Current strategies of conservative and operative treatment of the most frequent muscular disorders]

Though up to now no causal treatment for the majority of neuromuscular disorders is available, their disease progress and above all the quality of life of these patients can be decisively improved by established medical procedures. The main symptom is variably rapid, progressive muscle weakness, which leads to muscular imbalance and differently manifested impairment of motor functions. This results in the essential orthopaedic problems in these patients, e.g. contractures and deformities of the lower and upper extremities, foot deformities and sitting instability due to progressive scoliosis. Since the affected muscles have no physiological adaptability, they cannot be trained like healthy muscles. The orthopaedic treatment includes conservative methods, e.g. physiotherapy, orthotic devices and aids as well as surgical spine stabilisation and correction of the contractures of the lower extremities. Very important in the care of patients with neuromuscular disorders are the early prophylaxis and treatment of respiratory insufficiency by regular respiratory therapy to learn breathing and coughing techniques and self-exercises as well as the timely initiation of assisted ventilation.

Treatment and complications in flaccid neuromuscular scoliosis (Duchenne muscular dystrophy and spinal muscular atrophy) with posterior-only pedicle screw instrumentation

Literature has described treatment of flaccid neuromuscular scoliosis using different instrumentation; however, only one article has been published using posterior-only pedicle screw fixation. Complications using pedicle screws in paralytic neuromuscular scoliosis has not been described before. To present results and complications with posterior-only pedicle screws, a retrospective study was carried out in 27 consecutive patients with flaccid neuromuscular scoliosis (Duchenne muscular dystrophy and spinal muscular atrophy), who were operated between 2002 and 2006 using posterior-only pedicle screw instrumentation. Immediate postoperative and final follow-up results were compared using t test for Cobb angle, pelvic obliquity, thoracic kyphosis and lumbar lordosis. Perioperative and postoperative complications were noted from the hospital records of each patient. Complications, not described in literature, were discussed in detail. Average follow-up was 32.2 months. Preoperative, immediate postoperative and final follow-up Cobb angle were 79.8 degrees , 30.2 degrees (63.3% correction, p < 0.0001) and 31.9 degrees , respectively; and pelvic obliquity was 18.3 degrees , 8.9 degrees (52% correction, p < 0.0001) and 8.9 degrees . Postoperative thoracic kyphosis remained unchanged from 27.6 degrees to 19.9 degrees (p = 0.376); while lumbar lordosis improved significantly from +15.6 degrees to -22.4 degrees lordosis (p = 0.0002). Most patients had major to moderate improvement in postoperative functional and ambulatory status compared to the preoperative status. Thirteen (48.1%) perioperative complications were noted with five major complications (four respiratory in the form of hemothorax or respiratory failure that required ventilator support and one death) and eight minor complications (three UTI, two atelectasis, two neurological and one ileus). Postoperatively, we noted complications, such as coccygodynia with subluxation in 7, back sore on the convex side in 4 and dislodging of rod distally in 1 patient making a total of 12 (44.4%) postoperative complications. Of 12 postoperative complications, 6 (50%) required secondary procedure. We conclude that although flaccid neuromuscular scoliosis can be well corrected with posterior-only pedicle screw, there is a high rate of associated complications.

[Long term domiciliary mechanical ventilation in patients with neuromuscular disease (indications, establishment and follow up)]

Neuromuscular diseases represent a heterogeneous group of pathologies which common feature is the development of a restrictive ventilatory failure.

BACKGROUND

Respiratory insufficiency of neuromuscular origin manifests itself by functional symptoms that must be carefully searched for in the history, such as headaches, sleep disorders, or dyspnoea of effort, sometimes very mild, or in severe cases associated with orthopnoea. Follow up should be multi-disciplinary. On the respiratory level regular measurement of blood gases, vital capacity, maximum inspiratory and expiratory pressures as well as sleep studies, will detect the criteria for mechanical ventilation (hypercarbia > 45 mm Hg, nocturnal desaturation < 88%, vital capacity < 60%, PImax < 60 cm H2O).

STATE OF THE ART

The establishment of mechanical ventilation is a major decision for patients with neuromuscular disease because of the important physical, psychological, social and sometimes financial consequences. The patients and their family must be instructed precisely in order to obtain the best possible observation and compliance. The establishment requires a stay in hospital of several days to optimise the choice of ventilator, its settings, and connections. The link with the organisation managing the domiciliary ventilation is fundamental in ensuring follow up after discharge from hospital. Techniques of cough assistance must be taught to each neuromuscular patient requiring mechanical ventilation.

CONCLUSION

Ventilation of neuromuscular patients requires careful evaluation of the indications and rigorous follow up by a multidisciplinary team with wide experience of this type of disease.

Physical complaints in ageing persons with spinal muscular atrophy

OBJECTIVE

While life expectancy is improving for persons with spinal muscular atrophy, new physical complaints may arise. To investigate this, we studied persons with a long duration and severe course (high functional limitations) of the disease.

DESIGN

Cross-sectional descriptive study.

SUBJECTS/PATIENTS

Persons with spinal muscular atrophy.

METHODS

Questionnaires and structured interviews on prevalence of physical complaints and their duration. Of 190 questionnaires 99 were returned; of 23 persons (with the longest disease duration and high functional limitation level) selected for structured medical interviews 9 participated.

RESULTS

Patterns common within and different between the different types of spinal muscular atrophy were identified. Of the 10 most common complaints, types 1-2 had a significantly higher prevalence of kyphoscoliosis, difficulty in coughing, joint contractures and voice/speech problems, while type 3 had a significantly higher prevalence of fatigue. No statistically significant correlation was found between the appearance of physical complaints and disease duration. However, sleeping and swallowing problems were in the 5 most common complaints with the shortest mean time of appearance. The structured interview revealed hypermobility in the hand, suffusion of the eyes, and itching as new complaints with high prevalence.

CONCLUSION

There are indications that the frequency of less well-known physical complaints increases with ageing.

Pulmonary function and scoliosis in children with spinal muscular atrophy types II and III

AIMS

The objectives were to evaluate the clinical course of spinal muscular atrophy (SMA) types II and III patients necessitating scoliosis surgery at the National University Hospital, Singapore.

METHODS

A retrospective review of SMA types II and III patients, born over a 10-year period between 1983 and 1992, was conducted.

RESULTS

There were eight patients: four with SMA type II and four with SMA type III. The mean age at scoliosis surgery was 9 years 7 months (range 7 years 6 months-12 years 4 months). The mean preoperative Cobb angle was 65.4 degrees (range 43-90 degrees ) and the mean postoperative Cobb angle was 22.6 degrees (range 12-45 degrees ), with a mean correction of 64.8% (range 47.7-77.8%). The decline in percentage predicted forced vital capacity (FVC) was 7.7% (95% CI: 12.4% to 3.0%) per year preoperatively and this was reduced to 3.8% (95% CI: 5.8% to 1.9%) per year postoperatively. The mean length of preoperative and postoperative lung function follow-up was 6.3 months (range 0.03-31 months) and 44 months (range 0-110 months), respectively.

CONCLUSIONS

This study suggests that pulmonary function in SMA types II and III continues to decline after scoliosis surgery, though the rate of decline is less marked. Overall, the combined results from this study and all other previously published studies are conflicting in regard to the effect of scoliosis surgery on pulmonary function in SMA types II and III, though half of the studies (3 of 6) did demonstrate a continued decline in lung function postoperatively. This decline in pulmonary function despite spinal stabilization is likely secondary to the progressive neuromuscular weakness of the disease.