Transforaminal intrathecal delivery of nusinersen using cone-beam computed tomography for children with spinal muscular atrophy and extensive surgical instrumentation: early results of technical success and safety

Abstract

Background: Nusinersen, the only treatment approved by the United States Food and Drug Administration for spinal muscular atrophy (SMA), is delivered intrathecally. Many children with SMA have extensive spinal instrumentation and deformities, often precluding the use of standard approaches for gaining intrathecal access. Furthermore the anatomical distortion that often occurs with rotoscoliosis can complicate the use of fluoroscopic guidance. Compared to fluoroscopy, CT affords superior guidance for complex needle placements. This opens up alternatives to the posterior (interlaminar) technique, including transforaminal and caudal approaches.

Objective: This study describes the early results of technical success, complications and radiation dose of intrathecal delivery of nusinersen using cone-beam CT guidance with two-axis fluoroscopic navigational overlay.

Materials and methods: We conducted a retrospective review of 15 consecutive nusinersen injections performed in four children with SMA and extensive spinal hardware precluding standard posterior lumbar puncture techniques. These children were treated using transforaminal thecal access employing cone-beam CT with navigational overlay. We analyzed results including technical success, complications and total fluoroscopy time.

Results: All procedures were technically successful. No major complications and one minor complication were reported; the minor complication was a post-procedural neuropathic headache that was attributed to procedural positioning and was treated successfully with gabapentin. The average procedural fluoroscopy time and air kerma were 1.9 min and 55.8 mGy, respectively.

Conclusion: Cone-beam CT guidance with two-axis navigational overlay is a safe, effective method for gaining transforaminal intrathecal access in children with spinal abnormalities and hardware precluding the use of standard techniques.

Keywords: Children; Cone-beam computed tomography; Lumbar puncture; Nusinersen; Spinal muscular atrophy; Transforaminal.