Dorsal Root Ganglion: A More Precise Target
Dorsal root ganglion (DRG) spinal stimulation may be an option if traditional cervical SCS yields suboptimal pain control, or causes paresthesia over a wider area than desirable.
DRG spinal stimulation is thought to offer a more precise targeting of pain, including hand pain. The DRG is a cluster of fixed nerves in the spine that play a key role in transmitting pain signals from the peripheral nervous system to the central nervous system.1 Stimulating the DRG allows pain signals to be blocked before transmission to the spinal cord.
Considered investigational devices by the FDA, DRG stimulators have been approved for a variety of indications in Europe, Australia, and other parts of the world. Although FDA approval is anticipated in the coming years, the initial indication is unlikely to include hand, arm, or neck pain.
Avoiding the Spine Altogether?
Peripheral nerve stimulation (PNS) can be considered for patients with peripheral nerve injuries. This neuromodulation technique involves placement of electrodes along the course of the peripheral nerves, avoiding involvement of the spinal cord. Although the electrodes have traditionally been placed using an operative approach, less invasive methods are now available and ultrasonography can be used as a guide.
Because PNS avoids involvement of the spinal cord, it can be used in patients who are not candidates for traditional cervical SCS, such as those with severe spinal stenosis. However, the equipment is designed for the neuroaxis and requires modification for peripheral use; challenges include leads crossing joints and limited locations for pulse generator placement.1 As a result, several new technologies are currently being developed specifically for use in the periphery.
One such technology, the StimRouter System (made by Bioness, Inc), uses radiofrequency to generate electrical stimulation wirelessly. The device was approved by the FDA in February, 2015 as an adjunct to treat chronic, intractable pain of peripheral nerve origin.4