Fig 1. A, The 19-gauge cannula with an internal mandrel is positioned against the anterior surface of the annulus fibrosus. The cannula is held by a surgical forceps to minimize x-ray exposure of the surgeon’s hand.

B, Cannula placement as observed under fluoroscopy.

C and D, The cannula is advanced into the disk, and the SpineWand device (D, arrow) is introduced into the nucleus pulposus via the cannula.

E, The device is activated and then rotated 360°(E) to create a spheric void by means of the loop-shaped active electrode (arrow). Between 2 and 4 voids are ablated in a linear direction to create a channel.

F, After the first channel into the disk is completed, the device is repositioned to a different part of the nucleus, with the placement depending on the topography of the herniation. For left-sided herniations, the first channel is made in an oblique direction, from the right anterolateral entry point toward the left posterolateral herniation; the other channel is made on the midline and directed toward the posterior profile of the disk. For a right-sided lesion, the first channel is directed obliquely toward the center of the disk; the second channel is directed toward the right paramedian, along the medial surface of the uncal process to reach the herniation in the posterior aspect of the disk.

G, A schematic drawing shows the entry route, with the clinician’s fingers pushing the trachea across the midline while protecting the neurovascular bundle.