# Surgical Access for Intrathecal Therapy in Spinal Muscular Atrophy with Spinal Fusion: Long-Term Outcomes of Lumbar Laminectomy

## TL;DR

This study shows that lumbar laminectomy can safely restore access for spinal drug delivery in SMA patients who have had spinal fusion.

## Contribution

The study demonstrates the long-term viability of lumbar laminectomy for intrathecal therapy in SMA patients with prior spinal fusion.

## Key findings

- Nine out of eleven patients successfully received Nusinersen through the laminectomy window.
- Eight treated patients reported subjective motor improvement and would undergo the procedure again.
- No major adverse events occurred during a mean follow-up of nearly four years.

## Abstract

Background/Objectives: Spinal muscular atrophy (SMA) is a neuromuscular disorder frequently associated with progressive scoliosis requiring posterior spinal fusion (PSF). While Nusinersen offers significant clinical benefit, its intrathecal administration is challenging in patients with extensive spinal instrumentation and solid fusion. This study aimed to evaluate the safety, feasibility, and patient acceptance of lumbar laminectomy as a method to restore intrathecal access for repeated Nusinersen delivery in this population. Methods: A retrospective review was conducted in eleven patients with SMA who underwent lumbar laminectomy following prior PSF and confirmed radiographic fusion. Surgical data, injection outcomes, and patient-reported experiences were collected. A structured questionnaire assessed technical success, imaging requirements, sedation, functional response, and satisfaction. Results: Nine out of eleven patients (81.8%) successfully initiated intrathecal Nusinersen therapy through the laminectomy window, receiving a mean of 11.7 injections (range: 10–14). Imaging guidance was used in five cases; three required sedation or anesthesia. Intraoperative dural tears occurred in three patients and were managed without complications. Eight out of nine treated patients reported subjective motor improvement and expressed willingness to undergo the procedure again. No hardware revisions or major adverse events were observed during a mean follow-up of 48.8 months. Conclusions: Lumbar laminectomy is a viable and well-tolerated technique to establish intrathecal access in SMA patients with prior PSF. This approach enables sustained drug delivery and may remain clinically relevant as new intrathecal therapies emerge.