Magnetic rod surgery safe, effective for kids with SMA type 1: Study
Researchers say surgery is 'viable and effective' way to manage scoliosis
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- Muscle weakness in SMA type 1 often leads to scoliosis.
- Magnetically controlled growing rod surgery is a way to safely manage scoliosis.
- MCGRs significantly reduce spinal curvature and allow for continued spinal growth.
Surgery to implant magnetically controlled growing rods (MCGRs) is a safe and effective option for children with spinal muscular atrophy (SMA) type 1 and scoliosis, according to a study.
“MCGR represents a viable and effective surgical strategy for managing [scoliosis] in the medically complex [SMA type 1] population,” the researchers wrote.
The study, “Safety and Efficacy of Magnetically Controlled Growing Rods for Early-Onset Scoliosis in the Era of Disease-Modifying Therapies: Mid-term Results in a Homogeneous Cohort of SMA-I Patients,” was published in the Journal of the Pediatric Orthopaedic Society of North America.
SMA is a genetic disorder marked by muscle weakness and wasting. Type 1 is one of the most severe forms of SMA, marked by motor symptoms that appear in early infancy. Without treatment, babies with type 1 SMA typically do not survive past early childhood, but several disease-modifying treatments have become widely available in recent years. These therapies can slow SMA progression, helping patients retain motor function and dramatically improving survival odds.
Scoliosis refers to a sideways curvature of the spine. People with SMA often have scoliosis due to weakness in the torso muscles that normally help support the spine. There’s ample data on successful management of scoliosis in milder forms of SMA that develop later in childhood. But for SMA type 1, there’s much less data on best practices, especially now that more patients are living longer.
Guidance for surgeons
Scientists in Italy reported outcomes in eight children with SMA type 1, ages 5-8, who had undergone surgical treatment for scoliosis.
“By isolating this specific [type of SMA], our findings offer detailed guidance for surgeons counseling families in the current post-[disease-modifying treatment] landscape, where survival into later childhood is now the established clinical reality,” the scientists said.
The patients in the report all underwent scoliosis surgery using MCGRs. With this type of surgery, rods are implanted along the spine to provide support. As the child ages, the rods can be adjusted with a magnet to support the growing spine. This approach eliminates the need for repeat surgeries, which are required if non-magnetic rods are used for similar purposes.
Results showed that MCGR surgery was safe. The surgery itself lasted about four hours, and no complications were reported. Over a mean of more than two years of follow-up, one complication was reported: A rod in a patient had a loose screw, which required a second surgery to fix.
To assess how the surgery affected scoliosis, the researchers used a measure called the Cobb angle; a higher Cobb angle indicates more severe scoliosis. Results showed the mean Cobb angle decreased from 71.9 degrees to 38.9 degrees, representing an improvement of 45.9%. Over follow-up, the mean Cobb angle worsened slightly, to 44.5 degrees.
Further improvements were noted in pelvic obliquity, which can make the pelvis unnaturally tilted or cause one hip to sit higher than the other. Consistent spinal growth was also achieved.
“While these mid-term findings are promising, larger multicenter prospective studies remain necessary to further evaluate the long-term durability of these constructs,” the scientists wrote. “Future research should also focus on the direct impact of surgical intervention on [lung] function and overall quality of life in this evolving patient population.”
