A recent study published in Pediatric Neurosurgery has found that the implantation of growth-friendly spinal implants (GFSI) with bilateral rib-to-pelvis fixation does not positively affect the parasol deformity, rib-vertebral angle (RVA), and thoracic and lung volumes in children with spinal muscular atrophy (SMA) experiencing spinal deformity directly and over time.
The present study investigated whether paraspinal GFSI with rib-to-pelvis fixation influences the collapsing parasol deformity in children with SMA. The research team recruited 37 pediatric patients with SMA and spinal deformity.
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Among them, 19 children were treated with bilateral GFSI, while 18 SMA children had no prior spinal treatment. Patients in the GFSI group were assessed before the GFSI treatment (T0), directly after implantation-surgery (T1), after an average follow-up of 4.6 years, with GFSI treatment (T2) and upon removal of GFSI before definite spinal fusion (T3).
On the other hand, definite spinal fusion was planned in the group without GFSI pre-treatment. Furthermore, demographic data were collected, and measurements, including scoliosis and kyphosis angles, parasol deformity and index, and convex and concave RVA, were measured on the radiographs, while thoracic and lung volumes were reconstructed using computed tomography images.
Study results revealed no significant differences between groups in age, height, weight, and BMI at the time of spinal fusion. Furthermore, no significant influence of GFSI on RVA was found over the 4.6-year follow-up period. Besides, it was noticed that the median kyphotic values did not differ considerably between the 2 groups, while the average scoliotic values were found to be significantly larger in patients without prior GFSI treatment, suggesting that no effect of GFSI treatment could be detected on either RVA, thoracic or lung volume. Finally, parasol deformity advanced over time despite GFSI.
“Our findings support the data of Livingston et al. for hypotonic neuromuscular patients who found no correlation between the parasol deformity and the degree of scoliosis in their patient population,” the study authors wrote.
The authors addressed several limitations in the study, including the small sample size and the challenges regarding the measurement of RVA due to the limited availability of CT images displaying full thoracic and lung volumes. Additionally, thoracic and lung volume data couldn’t be directly related to lung function, thereby lacking reliable lung function data to identify the effect of GFSI on lung function in patients with SMA.
Austein J, Austein F, Lüders KA, et al. Influence of paraspinal growth-friendly spinal implants (GFSI) in children with spinal muscular atrophy (SMA) on parasol deformity, rib-vertebral angles, thoracic and lung volumes. Pediatr Neurosurg. Published online June 14, 2023. doi:10.1159/000531549