Background:

Spinal deformity and prior spinal fusion pose technical challenges to lumbar puncture (LP) for nusinersen administration for patients with spinal muscular atrophy (SMA). In this retrospective study over two study phases, we evaluated (1) factors associated with difficult LP or unscheduled requirement for image guidance and (2) effectiveness of a triage pathway for selective use of image guidance and nonstandard techniques, particularly for patients with spinal instrumentation/fusion to the sacrum.

Methods:

With institutional review board approval, electronic health records, imaging, and administrative databases were analyzed for patients receiving nusinersen from January 2012 through September 2021. Descriptive statistics and univariate analyses were used.

Results:

From January 2012 to March 2018 (phase 1), among 82 patients with SMA, 461 of 464 (99.4%) LP attempts were successful. Univariate analyses associated difficulty with prior spinal instrumentation, higher body mass index, and severity of the spinal deformity. Based on this experience, starting in April 2018 (phase 2), 125 patients were triaged selectively for ultrasound, fluoroscopy, or Dyna computed tomography. Patients with spinal instrumentation/fusion to the sacrum were treated primarily via intrathecal ports (137 doses) or transforaminal LP (55 doses). From April 2018 through September 2021, 704 of 709 (99.3%) LPs were successful. In total from January 2012 to September 2021, 1415 doses were administered. Over 50% of LPs were performed by neurology nurse practitioners without image guidance. Safety outcomes were excellent.

Conclusions:

A stratified approach resulted in successful intrathecal nusinersen delivery and efficient resource allocation for patients with SMA, with or without complex spinal anatomy.