ORIGINAL ARTICLE Stimulation of Dorsal Root Ganglia for the Management of Complex Regional Pain Syndrome: A Prospective Case Series Jean-Pierre Van Buyten, MD*; Iris Smet, MD*; Liong Liem, MD † ; Marc Russo, MD ‡ ; Frank Huygen, MD, PhD § *Multidisciplinary Pain Center, Algemeen Ziekenhuis Nikolaas, Sint-Niklaas, Belgium; † Sint Antonius Hospital, Nieuwegein, the Netherlands; ‡ Hunter Pain Clinic, Broadmeadow, New South Wales, Australia; § Erasmus University, Rotterdam, the Netherlands & Abstract 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 stim- ulation 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. Quadri- polar 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 pro- gramed 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. Neuro- modulation 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 pares- thesia intensities independent of body position, suggests this stimulation modality may allow more selective and consistent targeting of painful areas than traditional SCS. & Key Words: complex regional pain syndrome, dorsal root ganglion, spinal cord stimulation, neuromodulation, pro- spective case study INTRODUCTION Complex regional pain syndrome (CRPS) is a pain disorder involving the extremities and is usually initiated after an injury, surgery, or vascular accident, although spontaneous development is also described. In addition Address correspondence and reprint request to: Jean-Pierre Van Buyten, MD, Multidisciplinary Pain Centre AZ Nikolaas, Moerlandstraat 1, 9100 Sint-Niklaas, Belgium. E-mail: vanbuyten@skynet.be. Disclosures: All of the authors are consultants to Spinal Modulation, Inc. This study was sponsored by Spinal Modulation, Inc. and was performed in compliance with all applicable international and local regulatory and ethical requirements. Submitted: July 26, 2013; Revision accepted: November 01, 2013 DOI. 10.1111/papr.12170 © 2014 World Institute of Pain, 1530-7085/13/$15.00 Pain Practice, Volume , Issue , 2014 –