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A2301
October 14, 2018
10/14/2018 3:30:00 PM - 10/14/2018 5:30:00 PM
Room North, Hall D, Area D
Dorsal Root Ganglion Stimulation for Chronic Pain
Robert J. McCarthy, Pharm.D, Timothy R. Lubenow, M.D.
Rush University Medical Center, Wheaton, Illinois, United States
Disclosures: R.J. McCarthy: None. T.R. Lubenow: None.
Introduction: Dorsal root ganglion (DRG) neurostimulation therapy that has been used in the treatment of complex regional pain syndrome and peripheral causalgias.1 Neuropathic pain is associated with a hyperexcitability state and DRG stimulation is targeting the pain transduction prior to reaching the spinal cord. There is limited data examining the efficacy and safety of long term use of DRG stimulation. The purpose of this prospective study was to evaluate pain and disability in patients with chronic pain who underwent permanent DRG stimulator placement for chronic lower extremity and back pain.

Materials and Methods: Following IRB approval, patients who underwent a permanent DRG stimulator implantation between June of 2016 to January of 2018 were enrolled. After obtaining informed consent patients were evaluated for pain (NRS 0 to 10), patient global impression of change (PGIC) and degree of disability (Owestry Disability Index) at 1, 3, 6, 12 and 18 M post permanent implantation. Data were compared between baseline and longest follow-up period and between groups of patients with follow-up of <6M, 6M to 12M and >12M post implantation.

Results:
Sixty-seven subjects have been studied post-implantation. The median (quartiles) follow-up was 8 (3 to 12) M, with 26, 26 and 17 in the <6M, 6M to 12M and >12M groups, respectively. Baseline NRS pain scores were 8 (6 to 9) and Owestry disability index 33% (28% to 37%). At longest follow-up NRS pain scores were 5 (2 to 7), median difference -2 (95% CI of the difference -5 to -1, P<0.001) and Owestry disability index was 23% (15% to 30%), median difference -10 (95% CI of the difference -2 to 16, P<0.001) (Figure 1). The median PGIC was 70% (40 to 85). When compared among patients with implantation of <6M, 6M to 12M and >12M there was no difference in change in NRS, Owestry disability index of PGIC from baseline (Figure 2). Five patients (7.4%) required revision of the leads placement, 2 (3%) had removal of leads following infection and 1 patient had foot drop 2 M after implantation.

Discussion:
The important finding of this study is that DRG stimulation was effective in reducing pain, increasing function and produced a clinically important improvement in patient impression of change. Other important findings were the sustained effect seen with long term implantation and the low number of complications or need for electrode adjustment/replacement. The DRG is an ideal target for stimulation because it contains the cell bodies of primary sensory neurons and synapses with pathways to the spinothalamic tract. Stimulation at the DRG allows greater specificity of dermatomal innervation of the painful body part, avoiding unnecessary stimulation of non-painful areas. References: Deer TR, Levy RM, Kramer J et al. Pain. 2017; 158:669-81.
Figure 1
Figure 2

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