Abstract
Background: Spinal muscular atrophy (SMA) is a genetic disorder that leads to progressive tetraparesis. Nusinersen is the first approved drug for the treatment of SMA and is administered via intrathecal injections. Neuromyopathic scoliosis and spondylodesis can impede lumbar punctures, thus necessitating the use of radiological imaging. Furthermore, dosimetry of this potentially lifelong therapy should be supervised.Methods: Fluoroscopy-assisted or computed tomography (CT)-guided intrathecal injections of nusinersen were performed in adult patients with SMA type 2 and 3. The mean effective dose was compared in patients with and without spondylodesis as well as in those with SMA type 2 and 3. The dosimetry was analyzed in relation to the motor function evaluated with the Revised Upper Limb module (RULM) score and the Hammersmith Functional Motor Scale-Expanded (HFMSE) score.Results: Fifteen patients with SMA type 2 and 3 underwent radiological imaging-assisted intrathecal injections. The mean effective dose per CT-guided injection per patient was 2.59 (±1.67) mSv (n = 12). The mean dose area product (DAP) per fluoroscopy-guided injection per patient was 200.48 (±323.67) μGym2 (n = 3). With increase in the number of injections, the effective dose (r = −0.23) (p < 0.05) and the DAP (r = −0.09) (p > 0.05) decreased. The mean effective dose in 4 patients without spinal fusion (SMA type 2) was 1.39 (±0.51) mSv, whereas that in 8 patients with spondylodesis (SMA type 2 and 3) was 3.21 (±1.73) mSv. The mean effective dose in 5 SMA type 2 patients with spondylodesis was 2.68 (±1.47) mSv (n = 5) and in 3 SMA type 3 patients was 4.00 (±1.82) mSv. Dosimetry did not show significant correlation with the clinical severity of the disease (RULM score: r = −0.045, p > 0.05 and HFMSE score: r = −0.001, p > 0.05).Conclusions: In SMA type 2 and 3 patients undergoing radiological imaging-assisted injections, the effective dose and DAP decreased during therapy with nusinersen. The mean effective dose in patients with spondylodesis was higher than that in patients without spondylodesis. Dosimetry should be monitored carefully in order to detect and prevent unnecessary radiation exposure.
Highlights
Spinal muscular atrophy (SMA) is an autosomal recessive, inherited, degenerative motor neuron disease with a prevalence of 1 per 10,000 births
We have reported the dosimetric data of Computed tomography (CT)- and fluoroscopy-guided lumbar punctures associated with the treatment of SMA with nusinersen
56 CT-guided injections were performed in 12 patients, while 14 injections were performed via fluoroscopy in three patients
Summary
Spinal muscular atrophy (SMA) is an autosomal recessive, inherited, degenerative motor neuron disease with a prevalence of 1 per 10,000 births. It leads to progressive muscle atrophy and weakness. Depending on the achieved motor milestones, SMA is distinguished into different phenotypes: infants with SMA type 1 (Werdnig-Hoffmann disease) never develop the ability to sit, and they typically die within the first 2 years because of respiratory failure without ventilatory support (“non-sitters”). Neuromyopathic scoliosis and spondylodesis can impede lumbar punctures, necessitating the use of radiological imaging. Dosimetry of this potentially lifelong therapy should be supervised
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
