Dorsal root ganglion stimulation yielded higher treatment success rate for complex regional pain syndrome and causalgia at 3 and 12 months: a randomized comparative trial

Abstract

Animal and human studies indicate that electrical stimulation of dorsal root ganglion (DRG) neurons may modulate neuropathic pain signals. ACCURATE, a pivotal, prospective, multicenter, randomized comparative effectiveness trial, was conducted in 152 subjects diagnosed with complex regional pain syndrome or causalgia in the lower extremities. Subjects received neurostimulation of the DRG or dorsal column (spinal cord stimulation, SCS). The primary end point was a composite of safety and efficacy at 3 months, and subjects were assessed through 12 months for long-term outcomes and adverse events. The predefined primary composite end point of treatment success was met for subjects with a permanent implant who reported 50% or greater decrease in visual analog scale score from preimplant baseline and who did not report any stimulation-related neurological deficits. No subjects reported stimulation-related neurological deficits. The percentage of subjects receiving ≥50% pain relief and treatment success was greater in the DRG arm (81.2%) than in the SCS arm (55.7%, P < 0.001) at 3 months. Device-related and serious adverse events were not different between the 2 groups. Dorsal root ganglion stimulation also demonstrated greater improvements in quality of life and psychological disposition. Finally, subjects using DRG stimulation reported less postural variation in paresthesia (P < 0.001) and reduced extraneous stimulation in nonpainful areas (P = 0.014), indicating DRG stimulation provided more targeted therapy to painful parts of the lower extremities. As the largest prospective, randomized comparative effectiveness trial to date, the results show that DRG stimulation provided a higher rate of treatment success with less postural variation in paresthesia intensity compared to SCS.

Figure 1.

Lead placement. The lead for dorsal root ganglion (DRG) stimulation is specialized to provide percutaneous entry through the epidural space, exiting through the foramen, and resting around the DRG. As shown in panel A, DRG leads were placed in the lateral epidural space near the target DRG. For the SCS arm (panel B), leads were placed in the medial or paramedial epidural space such that the caudal-most electrical contact was not caudal to the top of the L1 vertebral body on an anterior–posterior fluoroscopic view. Depending on the anatomical target, up to 16 contacts were placed for both study arms. Intraoperative testing to determine paresthesia overlap over pain areas was conducted during trial evaluation period.

Figure 2.

CONSORT diagram. *Subjects were enrolled if they met the inclusion criteria for the study. After consent, subjects were screened per exclusion criteria and exited if violations were revealed. AE, adverse event; DRG, dorsal root ganglion; SCS, spinal cord stimulation.

Figure 3.

Proportion of subjects in each group who met the primary end point. The proportion of subjects who met the composite end point of success defined as 50% or greater pain reduction at both the trial phase and the indicated follow-up visit without a stimulation-related neurological deficit in the modified intent-to-treat population is shown. Subjects who exited the study after randomization were considered treatment failures. At all study visits, the proportion of subjects in the DRG stimulation group with successful therapy was noninferior to SCS (Blackwelder test of 2 proportions, all P < 0.01). Superiority was also established at each time point. ^aP < 0.001, ^bP = 0.04, ^cP = 0.02, and ^dP = 0.005. Error bars represent 95% confidence interval. *n for the DRG and SCS groups, respectively. DRG, dorsal root ganglion; SCS, spinal cord stimulation.

Figure 4.

Postural variation in paresthesia intensity. Variation in the intensity of paresthesia was calculated as the difference in intensity during supine and upright positions, rated on an 11-point numerical rating scale. Wilcoxon test indicated that subjects using DRG stimulation had significantly less postural variation in paresthesia intensity than SCS subjects. *P < 0.001. DRG, dorsal root ganglion; SCS, spinal cord stimulation.

Figure 5.

Change in profile of mood states (POMS) at 12 months. Change from baseline scores was calculated for each patient on each domain and the total score for the POMS. Mean change scores from baseline to 12 months are represented for both the DRG stimulation and the SCS groups. Error bars represent standard error of the mean. *Significant between-group difference with P < 0.05. **Significant between-group difference with P < 0.001. DRG, dorsal root ganglion; SCS, spinal cord stimulation.