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

Spinal presentations in children with type 1 spinal muscular atrophy on nusinersen treatment across the SMA-REACH UK network: a retrospective national observational study

BACKGROUND

Prior to the introduction of disease-modifying treatments (DMTs), children with type 1 spinal muscular atrophy (SMA) typically did not survive beyond the age of 2 years; management was mainly palliative. Novel therapies have made this a treatable condition, resulting in increased life expectancy and more time spent upright. Survival and improved function mean spinal asymmetry is a new complication with limited data on its prevalence and severity and no current guidelines on management and treatment. This study aimed to evaluate the spinal presentation and management of type 1 SMA children on nusinersen across the SMA-REACH UK network.

METHODS

Spinal presentation and management of 80 children (age range 4 months-14 years, median 4 years 2 months) with type 1 SMA on nusinersen across the SMA-REACH UK network were reviewed through retrospective data analysis.

RESULTS

There were 60 type 1 children who developed a spinal asymmetry, of which 40 had kyphosis and 50 used a supportive thoraco-lumbar-sacral orthosis (TLSO). TLSOs were predominantly a one-piece jacket with abdominal hole, advised to be worn when upright during the day. Reduced neck range of movement was found in 33, 1 of these had plagiocephaly and 5 had torticollis. Of those with reduced neck range of movement, 26 (79%) had spinal asymmetry. Spinal surgery was performed in 7.

CONCLUSIONS

Our study confirms high prevalence of spinal asymmetry in this cohort, requiring long-term management planning. It provides information on presentation and treatment options, facilitating development of guidelines for these new complications observed in children surviving longer with DMTs.

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.

Treatment of Symptomatic Spinal Muscular Atrophy with Nusinersen: A Prospective Longitudinal Study on Scoliosis Progression

Background

Nusinersen treatment has demonstrated efficacy in improving clinical outcomes for spinal muscular atrophy (SMA), yet its impact on scoliosis progression remains unclear.

Objective

This study aimed to assess the progression of scoliosis in pediatric patients with SMA undergoing nusinersen treatment.

Methods

In this prospective study, data were systematically collected from Hong Kong pediatric SMA patients receiving nusinersen between 2018 and 2023. All patients had longitudinal radiographic studies pre-nusinersen, and at half-yearly or yearly intervals during treatment based on the scoliosis severity. Motor function evaluations were conducted pre-nusinersen, and after starting treatment at 6- and 12-month intervals.

Results

Twenty-three patients ((SMA type 1 (SMA1) = 8, SMA type 2 (SMA2) = 7, SMA type 3 (SMA3) = 8)) with a median age of 5.8 years (range: 0.4-17.5 years) at nusinersen initiation, and median follow-up duration of 3.4 years (range: 1.1-5.2 years) were included. During the study period, motor scores remained stable or improved in 83% of patients. However, scoliosis progressed across all subtypes, with mean annual progression rates of 5.2, 11.9, and 3.6 degrees in SMA1, SMA2, and SMA3 respectively. Patients initiating nusinersen between ages 5 and 11 years exhibited the most rapid progression, with rates of 11.8, 16.5, and 7.3 degrees per year in SMA1, SMA2, and SMA3 respectively. Positive correlations were observed between the difference in CHOP-INTEND score post-nusinersen and scoliosis progression in SMA1 (rs = 0.741, p = 0.041). Conversely, negative correlations were found between the difference in HFMSE score post-nusinersen and scoliosis progression in SMA2 (rs =-0.890, p = 0.012) and SMA3 (rs =-0.777, p = 0.028).

Conclusions

This study reveals that nusinersen treatment in symptomatic pediatric SMA patients with motor improvement is linked to increased scoliosis progression in SMA1, whereas it is associated with decreased progression in SMA2 and SMA3. Age, baseline Cobb angle, and motor milestone improvement are influential factors in scoliosis progression.

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.