Dorsal root ganglion stimulation (DRGS) may be an effective treatment for people with non-complex regional pain syndrome chronic pain diagnoses, although patients should be evaluated on a case-by-case basis. This is according to research published in Neuromodulation.
In light of increasing evidence suggesting that DRGS may be an option for treating multiple pain conditions besides complex regional pain syndrome, researchers conducted a systematic review of clinical experiences using DRGS for treating non-complex regional pain syndrome chronic pain.
Studies published after December 31, 1999, were eligible for inclusion. An initial search found 1811 reports, and 28 studies published between 2012 and 2020 that included 354 patients were included in the final analysis.
Investigators categorized reports based on pain etiology: axial back pain, pelvic pain, other focal peripheral neuropathies, and multiple concomitant pain etiologies. All included reports were of a low evidence tier and included observational data. Trials were considered successful if patients experienced a reduction of more than 50% from baseline pain scores.
Six studies focused solely on low back pain (n=78 patients). Five of these reports were case series, with follow-up times ranging from 6 weeks to 26 months. Five studies demonstrated a reduction of pain of more than 50% from baseline at the time of the last follow-up; complications included 5 participants with lead migration and 1 with device pocket pain.
Pelvic and groin pain were reported on in 7 studies (4 case series, 3 case reports; n=59 patients) and included chronic pelvic pain, pudendal neuralgia, coccydynia, intractable neuropathic pain of the groin, and intractable chronic bilateral testicular pain.
Follow-up times ranged from 7 days to 12 months. In 5 of the studies, patients generally responded well to DRGS treatment, demonstrating a greater than 70% reduction in pain at the last follow-up.
Nine studies involved other focal peripheral neuropathies (6 case series, 3 case reports; n=65 patients). One study did include participants who met complex regional pain syndrome II criteria.
Follow-up ranged from 5 to 36 months, and pain syndromes included phantom limb pain, post-Lyme disease peripheral neuropathic pain, anterior cutaneous nerve entrapment, postsurgical knee pain, neuropathic pain after peripheral nerve injury, diabetic peripheral neuropathy, refractory loin pain hematuria syndrome, and idiopathic small fiber neuropathy of the left foot. Eight studies demonstrated 50% or greater relief of pain, and 18 patients experienced complications.
The remaining 5 studies focused on several chronic pain etiologies (n=147 participants). Four studies included people diagnosed with complex regional pain syndrome (n=51). All 5 reports found a greater than 50% reduction in average pain at the time of the final follow-up, ranging from 3 days to 18 months. This group of studies had the most complications, with 81 adverse events reported in 4 studies, including temporary motor stimulation, infection, pocket pain, and device reprogramming.
Of the studies, 20 included a secondary outcome measure, primarily focused on physical function, quality of life, and decrease in the use of pain medication.
“Previous research has shown that the DRG is a prime target for mitigating and reducing chronic pain, given its modulation of signaling between the peripheral and the CNS via the T-junction,” the researchers wrote. “While only approved for use in treating [complex regional pain syndrome], we found across review and analysis supportive evidence of DRGS in 28 reports…with a variety of pain syndromes.”
Despite these positive results, evidence from well-designed, high-level studies and recommendations from consensus committee experts are needed to validate this treatment modality.
“It may be reasonable and appropriate to evaluate patients for DRGS candidacy on a case-by-case basis particularly if they manifest focal pain syndromes refractory to noninterventional measures and may not be ideal candidates for other forms of neuromodulation,” the researchers concluded.
Disclosure: One study author declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Stelter B, Karri J, Marathe A, Abd-Elsayed A. Dorsal root ganglion stimulation for the treatment of non-complex regional pain syndrome related chronic pain syndromes: a systematic review. Neuromodulation. Published online January 26, 2021. doi:10.111/ner.13361