Scoliosis, hip dislocations common in children with SMA, study finds
Targeted interventions needed for youngsters with musculoskeletal problems
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- A new study found that children with SMA frequently develop musculoskeletal issues such as scoliosis and hip dislocations.
- These problems often worsen with age, especially in nonambulatory children and those with SMA type 2.
- Combining Spinraza with rehabilitation may help, but new interventions are needed to improve outcomes, the researchers say.
Children with spinal muscular atrophy (SMA) frequently develop what are known as musculoskeletal deformities, or bone and muscle-related problems that include scoliosis, a sideways curvature of the spine, and hip dislocations, according to a new study from China.
The researchers found that these problems often persisted or worsened over time, despite treatment with newer medications such as Spinraza (nusinersen).
However, combining that approved therapy with rehabilitation may be beneficial for children with SMA, the researchers noted.
Still, new strategies are needed to keep problems such as scoliosis, dislocations, and joint contractures — when muscles, tendons, joints, or other tissues tighten or shorten, causing a deformity — from worsening. New treatments could help to improve prognoses for these young patients, the team noted.
“Further research is warranted to develop targeted interventions and optimize musculoskeletal outcomes in this population,” the researchers wrote.
The study, “Musculoskeletal deformities in children with spinal muscular atrophy: a multicenter cross-sectional study with longitudinal follow-up,” was published in the Annals of Physical and Rehabilitation Medicine by a team from Guangzhou Women and Children’s Medical Center.
It’s long been noted that children with SMA, particularly those with type 2 and type 3, have a tendency to develop musculoskeletal deformities, such as scoliosis, joint contractures, and hip dislocation. However, much of that research is decades old and offers limited insight into the more severe SMA cases, such as type 1.
This gap is especially important today, as the availability of disease-modifying treatments has changed the outlook for many children with SMA. One such treatment, Spinraza, works by increasing production of the survival motor neuron protein and has been shown to improve motor function and extend survival, especially in children with SMA type 1. I.
“As drug treatment becomes available and rehabilitation guidelines are updated, children with SMA are increasingly poised to receive standard rehabilitation management, which potentially influences the natural progression of disease and clinical manifestation,” the scientists wrote.
Assessing scoliosis, other muscoskeletal issues in SMA children
Now, a team from Guangzhou Medical University sought to assess the prevalence of musculoskeletal issues among children with SMA. To that end, the researchers evaluated data from 229 children, ages 3 months to 18 years, across nine hospitals in China. All had participated in a clinical trial of Spinraza called DEVOTE (NCT04089566).
Most children (65%) had SMA type 2, followed by SMA type 3 (24%); 11% had SMA type 1. Musculoskeletal deformities were found to be common: 59% of the youngsters had scoliosis, 62% had joint contractures, and 21% had hip dislocation. Approximately one-fifth (19%) experienced all three conditions at the same time.
These complications were most frequent in children with SMA type 2, while those with type 3 were less affected. The issues became more common as children grew older until age 12, after which a slight decline was seen. Children who were unable to walk had the highest rates of deformities, the data showed.
Joint contractures most often affected the lower limbs, especially the ankles and knees, regardless of SMA type.
Age was a risk factor, with each additional year of life was associated with an approximately 1.3 times higher chance of developing scoliosis, joint contractures, or hip dislocation, according to the researchers.
Musculoskeletal deformities are highly prevalent in children with SMA. … An integrated approach combining [Spinraza] treatment with rehabilitation management may help stabilize or improve musculoskeletal outcomes in this population.
Children with SMA type 1 or 2 were also far more likely than those with type 3 to develop one or multiple deformities. Sex and treatment with Spinraza did not affect the risk of having these complications.
In a subgroup of 83 children followed over one to two years while on treatment with Spinraza and rehabilitation, deformities continued to progress in most (61.5%), while in 33% they remained stable. In a smaller percentage, 5%, deformities eased after one year. In the subsequent year, 42% children remained stable, while 58% experienced progression.
“Musculoskeletal deformities are highly prevalent in children with SMA,” the researchers wrote, adding that their findings suggest “an integrated approach combining [Spinraza] treatment with rehabilitation management may help stabilize or improve musculoskeletal outcomes in this population.”
Among the study’s limitations, the investigators noted the small group of participants with SMA type 1, the limited number of patients (32) who completed follow-up, and the fact that “potential predictive factors, such as assistive devices, rehabilitation techniques, and the duration and frequency of rehabilitation, were not fully accounted for.” The team also noted that starting Spinraza treatment when the patients were already experiencing these complications may have limited the treatment’s impact.
