CT-guided Lumbar Puncture for Intrathecal Nusinersen Injection in Patients with Spinal Muscular Atrophy: Technical Effectiveness, Safety, and Radiation Dose

Purpose Spinal muscular atrophy (SMA) is a rare neuromuscular disease treated with intrathecal nusinersen. In patients with complex spinal anatomy or spinal instrumentation, repeated lumbar punctures can be challenging. CT guidance is a valuable alternative. This study evaluated feasibility, safety, and radiation exposure of CT-guided nusinersen administration in SMA. Methods In this retrospective single-center study, 458 CT-guided nusinersen injections performed in 44 SMA patients between October 2017 and August 2024 were analyzed. Technical success, complications, procedure times, and radiation exposure were assessed between subgroups. Results Overall technical success was 98.3% (449/458). Success rates were slightly lower in patients with dorsal spondylodesis (97.1% vs. 98.8%, p=0.311). Complications occurred in 1.1% (5/458). Patients with spondylodesis had significantly longer puncture (median 11.9 vs. 10.3 min, p=0.0031) and procedure durations (16.3 vs. 14.0 min, p=0.0028) and higher radiation doses (CTDIvol 9.68 vs. 7.24 mGy, DLP 142 vs. 105 mGy·cm, effective dose 2.22 vs. 1.74 mSv; all p<0.0001). Failed or complicated procedures were linked to prolonged durations (p<0.0001) and higher radiation exposure. Needle repositioning was more frequent in spondylodesis, failed, and complicated cases, and correlated with duration and radiation dose. Technical success was independent of patient positioning. Conclusion CT-guided lumbar puncture for intrathecal nusinersen injection is a safe and effective technique, even in patients with complex spinal anatomy. Dorsal spondylodesis increases complexity, reflected by longer durations, more repositioning, and higher radiation exposure. Tailored puncture level selection, optimized positioning, and dose-reduction strategies are essential for high success rates and minimizing radiation burden in long-term SMA therapy.