Ultrasound-assisted or Landmark-based Intrathecal Administration of Nusinersen in Adult Patients With Spinal Muscular Atrophy (The EchoSpin Study)

All procedures were performed with patients either seated or placed in a lateral decubitus. After skin disinfection with 2% chlorhexidine in 70% alcohol, using a convex array, the L3-4 or L4-5 intervertebral space was identified and a left paramedian sagittal oblique view was obtained; the probe was rotated 90° into a transverse orientation, centered on the neuraxial midline, and moved in either the cephalad or caudal direction to obtain a transverse interlaminar view; the intersection between the two markings of the spinal midline and interspinous space was identified as the spinal entry point of the needle. After local anesthesia (LA) with lidocaine 2%, a 25-gauge non-traumatic 90 mm Whitacre spinal needle or a traumatic 90 mm Quincke spinal needle was used to access the subarachnoid space. After confirmation of cerebrospinal fluid (CSF) flow, 5 mL of CSF were removed. Subsequently, nusinersen was administered intrathecally over 1-3 min.

All procedures were performed with patients placed in their most comfortable position (either seated or placed in a lateral decubitus). After skin disinfection with 2% chlorhexidine in 70% alcohol, conventional palpation of the superior aspect of iliac crest was performed and the palpated intercristal line was assumed to cross the spine at L4 vertebral body or L4-L5 interspace. The skin was marked with horizontal and vertical lines at the L3-L4 or L2-L3 interspaces and was referred as entry point of the needle. The procedure was then completed in the same fashion as for US-assisted technique.