Stimulation of dorsal root ganglia for the management of complex regional pain syndrome: a prospective case series.
BACKGROUND
Complex regional pain syndrome (CRPS) is a chronic and progressive pain condition usually involving the extremities and characterized by sensorimotor, vascular, and trophic changes. Spinal cord stimulation (SCS) is an effective intervention for this condition, but is hampered by the technical challenges associated with precisely directing stimulation to distal extremities. Dorsal root ganglia (DRG) may be more effective as a physiological target for electrical modulation due to recruitment of the primary sensory neurons that innervate the painful distal anatomical regions.


METHODS
Eleven subjects diagnosed with uni- or bilateral lower-extremity CRPS were recruited as part of a larger study involving chronic pain of heterogeneous etiologies. Quadripolar epidural leads of a newly developed neurostimulation system were placed near lumbar DRGs using conventional percutaneous techniques. The neurostimulators were trialed; 8 were successful and permanently implanted and programed to achieve optimal pain-paresthesia overlap.


RESULTS
All 8 subjects experienced some degree of pain relief and subjective improvement in function, as measured by multiple metrics. One month after implantation of the neurostimulator, there was significant reduction in average self-reported pain to 62% relative to baseline values. Pain relief persisted through 12 months in most subjects. In some subjects, edema and trophic skin changes associated with CRPS were also mitigated and function improved. Neuromodulation of the DRG was able to provide excellent pain-paresthesia concordance in locations that are typically hard to target with traditional SCS, and the stimulation reduced the area of pain distributions.


CONCLUSIONS
Neuromodulation of the DRG appears to be a promising option for relieving chronic pain and other symptoms associated with CRPS. The capture of discrete painful areas such as the feet, combined with stable paresthesia intensities independent of body position, suggests this stimulation modality may allow more selective and consistent targeting of painful areas than traditional SCS.
Multidisciplinary Pain Center, Algemeen Ziekenhuis Nikolaas, Sint-Niklaas, Belgium.
Jean-Pierre
JP
Van Buyten
Iris
I
Smet
Liong
L
Liem
Marc
M
Russo
Frank
F
Huygen
D000293:Adolescent; D000328:Adult; D000368:Aged; D059350:Chronic Pain / Q000628:therapy*; D015331:Cohort Studies; D020918:Complex Regional Pain Syndromes / Q000628:therapy*; D004599:Electric Stimulation Therapy / Q000379:methods*; D004824:Epidural Space; D005260:Female; D005727:Ganglia, Spinal; D006801:Humans; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D059408:Pain Management / Q000379:methods; D010147:Pain Measurement / Q000379:methods; D011446:Prospective Studies; D016896:Treatment Outcome; D055815:Young Adult
complex regional pain syndrome; dorsal root ganglion; neuromodulation; prospective case study; spinal cord stimulation