Dorsal Root Ganglion Stimulation Research Articles

Exploring Psychophysical and Neurophysiological Responses to Intra-Epidermal Electrical Stimuli in Patients With Persistent Spinal Pain Syndrome Type 2 with a Spinal Cord Stimulator.

There is a lack of measures that provide insights into how spinal cord stimulation (SCS) modulates nociceptive function in patients with persistent spinal pain syndrome type 2 (PSPS-T2). Recently, we observed altered nociceptive detection thresholds (NDTs) in response to intra-epidermal electrical stimulation (IES) on the feet of PSPS-T2 patients when dorsal root ganglion stimulation was turned on. Furthermore, we observed altered NDTs and evoked potentials (EPs) in response to IES on the hands of PSPS-T2 patients. To explore whether EPs were obstructed by SCS artifacts, we applied IES twice to the hands of patients with SCS turned on (SCS-ON/ON group). To explore possible confounding effects of SCS outside the stimulated area, we repeated IES on the hands of these patients, once with SCS turned off and subsequently once with SCS turned on (SCS-OFF/ON group). The results demonstrated that EPs were not obstructed by SCS artifacts. Additionally, NDTs and EPs did not significantly change between measurements in the SCS-ON/ON and the SCS-OFF/ON groups. Therefore, the results suggested that possible confounding effects of SCS outside the nociceptive system did not interfere with the detection task performance. This work warrants further exploration of NDT-EP phenomena in response to IES at the painful feet of patients.Clinical Relevance-This work contributes to developing a clinical tool to explore psychophysical and neurophysiological biomarkers for observing modulating effects of SCS in patients with PSPS-T2.

Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation of C2 Dorsal Root Ganglion for the Treatment of Refractory Atypical Facial Pain: A Technical Report and Case Series

BackgroundChronic craniofacial pain can be difficult to manage clinically. This technical report documents the peripheral nerve stimulation of the C2 dorsal root ganglion as an effective modality to treat refractory atypical facial pain. Materials and MethodsIn this case series, three patients with chronic refractory atypical facial pain and p >50% pain relief following diagnostic C2 dorsal root ganglion blockade underwent ultrasound-guided percutaneous placement of a peripheral nerve stimulator adjacent to the C2 dorsal root ganglion. Patients were then observed clinically and monitored for improvement in symptoms and adverse events. ResultsThree patients underwent peripheral nerve stimulator placement. At follow-up, there were no reported adverse events, and all patients reported satisfactory improvement in pain. ConclusionThe neuromodulation of C2 dorsal root ganglion via ultrasound-guided percutaneously implanted peripheral nerve stimulator is a novel and potentially effective approach for the management of chronic refractory craniofacial pain.

ID: 212641 Salvage Therapy With Bilateral T12 and S1 DRG Stimulation for Post-Laminectomy Syndrome: A Case Report

Neuromodulation with tonic spinal cord stimulation (t-SCS) is well evidenced to manage chronic pain syndromes. However, for patients with post-laminectomy syndrome refractory to t-SCS, salvage therapies such as alternative waveforms of SCS (burst, high frequency, or multiple waveform) or dorsal root ganglion (DRG) stimulation have been studied. DRG stimulation is an emerging option for salvage therapy and was shown to be non-inferior and superior to t-SCS in treating lower extremity neuropathic pain for CRPS in the ACCURATE study. DRG stimulation’s use as salvage therapy for post-laminectomy syndrome is poorly reported. In this case, we present the treatment approach with DRG stimulation as salvage treatment for post-laminectomy syndrome refractory to t-SCS.

ID: 209955 Dorsal Root Ganglion Stimulation as an Effective Modality for Pelvic Pain From Rectal Cancer

Cancer related pelvic pain severely impairs the quality of life and can be resistant to a variety of interventions. Neuromodulation is emerging as a potential avenue to manage pain and improve quality of life. Unlike Spinal cord stimulators (SCS), dorsal root ganglion (DRG) stimulation targets focal areas and is an attractive target for neurostimulation. Over the past decade, DRG stimulation has become a part of the armamentarium to effectively treat discrete areas of pain particularly resistant to other interventional modalities. A case series showed significant analgesic benefit from DRG stimulation with L1/S2 lead placement in patients with chronic pelvic pain resistant to a variety of other therapies.

ID: 200814 Open Dorsal Root Ganglion Stimulator Lead Placement in the Setting of Previous Fusion: Case Report

Dorsal Root Ganglion (DRG) Stimulation is a relatively new neuromodulation technique that has been showing increasing promise in chronic pain management. Due to unique anatomical attributes, DRG stimulation allows for posture independent, precise, and targeted neuromodulation with lower energy use, leading to the need for fewer generator changes.

Dorsal root ganglion stimulation for chemotherapy-induced peripheral neuropathy.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common consequence of cancer treatment that can be persistent and difficult to manage. Dorsal root ganglion stimulation (DRG-S) is a recently introduced but understudied treatment modality. This study explored the effect of DRG-S on pain and symptom burden associated with CIPN. Patients with CIPN who underwent a DRG-S trial between January 2017 and August 2022 were identified through chart review after IRB approval was obtained. Demographic data, procedure details, pre-and postoperative scores, including the Numerical Rating Scale (NRS) and Edmonton Symptom Assessment System (ESAS), and duration of follow-up were recorded. Statistical analysis included descriptive statistics and paired t-tests to compare pre-and postoperative scores. Nine patients with an even mix of solid and hematologic malignancies underwent DRG-S trial and had a statistically significant decrease in NRS scores, with a mean reduction of 2.3 in their average pain (p = 0.014), 2.6 in worst pain (p = 0.023), and 2.1 in least pain (p = 0.018). Eight patients (88.9%) underwent permanent DRG-S implantation. Mean NRS scores remained lower than preoperative baselines through the first year of follow-up. Statistically significant reductions were noted at 3 months in average (2.1, p = 0.006) and least pain scores (1.9, p = 0.045), which further decreased after 6-12 months (average: 3.6, p = 0.049; least: 3.4, p = 0.023). Only the pain component of ESAS scores showed a significant reduction with DRG-S (2.0, p = 0.021). All patients endorsed improved sensation, 75% decreased their pain medication usage, and 37.5% reported complete pain relief by 2 years. Dorsal root ganglion stimulation can be an effective treatment for pain related to CIPN and deserves further investigation.

ID: 211385 Modeling the Effects of Dorsal Root Ganglion Stimulation on a Population of Biophysically Distinct C-neurons

Dorsal root ganglion stimulation (DRGS) is an effective therapy for managing chronic pain. However, some patients do not receive adequate pain relief from DRGS. We do not understand the mechanisms of action of DRGS-induced pain relief, preventing us from optimizing the therapy to maximize pain relief in all patients. One hypothesis is that DRGS augments the filtering of action potentials (APs) at the T-junction of nociceptive C-neurons. However, conventional neurostimulation theory suggests direct action on nonmyelinated cells, such as C-neurons, is unlikely at stimulation amplitudes utilized in clinical DRGS programming. We employed a computational approach to study how biological variability between C-neurons may affect their response to DRGS.

ID: 210523 Prospective Evaluation of Washout Periods Following Dorsal Root Ganglion Stimulation Trial

Dorsal root ganglion stimulation (DRG-S) places an electrical field over the DRG to modulate neural transmission. As mechanisms underlying DRG-S have become elucidated, it is clear there are actions distinct from that of conventional spinal cord stimulation (SCS). DRG-S is efficacious when delivered as a subthreshold and paresthesia-free tonic waveform, at frequencies as low as 4 Hz, and when stimulation is delivered intermittently, none of which are possible with SCS. The endogenous opioid system may play a role in pain relief with DRG-S, which should lead to prolonged washout times based on preclinical research. This study aimed to measure the time for pain to return to baseline pain levels after subjects’ 1-week DRG-S trials ended.

ID: 210704 Objectively Measured Improvement in Patients Treated With Dorsal Root Ganglion Stimulation

Dorsal root ganglion stimulation (DRG-S) is effective in treating CRPS type I or II (causalgia) of the groin and lower extremities. Despite considerable efforts toward establishing biomarkers of pain, methods to measure pain are primarily focused on patient reported outcomes (PRO). This study will quantify changes in function, affect, sleep, and quality of life using a commercially available wearable device and correlate these objective metrics with patient-reported outcomes collected prior to and post permanent implant of a DRG-S system.

ID: 203617 One-Year Safety Analysis Using DRG-Stimulation for the Treatment of Lower Limbs CRPS I and II

Dorsal root ganglion stimulation (DRG-S) is effective for the treatment of chronic focal pain conditions1 and superior to traditional spinal cord stimulation (SCS) in the treatment of CRPS types I and II (causalgia).2,3 To provide continued evidence of safety after FDA approval, a post-market, prospective, single-arm, observational study in patients with CRPS types I or II of the lower limbs treated with DRG-S was designed (NCT02800863). The primary goal of the study was to show that the proportion of serious adverse effects (SAEs) in subjects who received a permanent implant was lower than a pre-specified goal of 15.5% after 12 months. SAEs were defined as safety-related device and non-device events that result in the subject's death or a serious deterioration in health that is life-threatening, results in permanent impairment, or requires medical intervention and hospitalization. The study descriptive endpoint was the proportion of subjects with device, procedure, or stimulation-related SAEs (SADE) or AE (ADE)

ID: 205005 Dorsal Root Ganglion Stimulation at L1 & L2 for Post- Ilioinguinal, Iliohypogastric, and Genitofemoral Neurectomy

We present a case report of a 36-year-old female that underwent neurectomy of ilioinguinal, iliohypogastric and genitofemoral nerves at an outside hospital and presented with severe left-sided groin pain. Patient developed chronic pain, post-cesarean section and the subsequent neurectomies worsened the symptoms. Dorsal root ganglion stimulation (DRGS) has emerged as novel treatment option for refractory chronic pelvic pain (CPP). DRGS delivers targeted target to focal areas and is able to reliably capture body parts like the pelvis making it an ideal modality for the treatment of CPP. We present successful resolution of symptoms once DRGS leads were placed at L1, and L2 neuroforamen.

ID: 213412 Comparison of Remote Programming and On-Site Programming in Patients With SCS and DRG Stimulation

Spinal cord and dorsal root ganglion stimulation (SCS and DRG) are standard of care in chronic neuropathic pain. During the COVID-19 pandemic, it was critical to arrange postoperative care. Furthermore, the disparity between travel times and transportation options could influence the decision on seeking healthcare. Lacking financial resources could enhance this issue.

ID: 208242 Successful Treatment of Sjogren's Small Fiber Neuropathy With Dorsal Root Ganglion Stimulation

Small fiber neuropathy (SFN) is a chronic neuropathic pain disorder that is caused by damage to peripheral nerves, including small and myelinated (Aδ) and unmyelinated (C) fibers.1 Small, somatic, and autonomic fibers are responsible for regulation of thermal and pain perception, which control autonomic and enteric functions. Symptoms include allodynia, burning, hyperesthesia, paresthesia, numbness, abnormal sweating, and others.1

ID: 214897 Peripheral Nerve Stimulation for Refractory Complex Regional Pain Syndrome Type I to Avoid Amputation

Peripheral nerve and dorsal root ganglion stimulation (DRG-s) are effective treatment modalities for focal complex regional pain syndrome (CRPS) that is limited to one or two dermatomes1,2,3. When deciding on a neural target for stimulation, consideration is given to the location of pain, MRI labeling, charge burden of external or internal pulse generator, spinal hardware, and medical comorbidities. While a reduction in pain of fifty percent or greater is often deemed a satisfactory response in the treatment of chronic pain, we describe a case were the patient sought amputation of her limb in the hopes a prosthetic extremity would provide improved function. Despite the risk of post amputation pain, there are patients that seek amputation for advanced CRPS that is refractory to treatment4,5,6. We proceeded with peripheral nerve stimulation (PNS) in addition to her DRG-s system in effort to avoid her upcoming amputation.

ID: 221335 Laminectomy for Dorsal Root Ganglion Stimulation Lead Placement: Outcomes and Surgical Technique

Dorsal root ganglion (DRG) stimulation for chronic pain has been supported by level I evidence and has been designed for percutaneous placement. Open placement of DRG leads via laminectomy has been rarely reported. We describe our early experience with open DRG lead placement via laminectomy.

ID: 210321 Effect of Low-Frequency Dorsal Root Ganglion Stimulation in the Treatment of Neuropathic and Nociceptive Pain

The role of stimulation parameters in dorsal root ganglion stimulation (DRG-S), especially of stimulation frequency, is not well understood. Previous studies documented higher effectiveness for frequencies as low as 20 Hz, but there is evidence that even lower values could lead to better outcomes. In this study, we investigate the influence of low-frequency DRG-S.

ID: 217375 Dorsal Root Ganglion Stimulation: An Off-Label Indication for Targeted Coverage of Chronic Pelvic Pain

Chronic pelvic pain (CPP) is a treatment-resistant, complex neuropathic pain state which encompasses a number of painful pelvic disorders affecting women in a range of reproductive ages including inguinal and pudendal neuralgia, coccydynia, and vulvodynia. A majority of the sensory neuroinnervation to the pelvis is derived from the sacral plexus, specifically the pudendal nerve. In contrast to traditional dorsal column stimulation, dorsal root ganglion (DRG) stimulation offers more targeted therapy to focal areas of pain.

ID: 216598 Effects of Sodium Channel Clustering on Activation Thresholds of Nonmyelinated Axons

It is hypothesized that some neurostimulation therapies, such as dorsal root ganglion stimulation (DRGS), may provide therapeutic benefit by activating nonmyelinated neurons (e.g., C-neurons). However, conventional neurostimulation theory suggests that extracellular electrical stimulation preferentially activates large-diameter myelinated neurons over small-diameter nonmyelinated neurons. Interestingly, a recent study of DRGS in rats demonstrated that the activation thresholds of nonmyelinated C-neurons are only ∼1.5 times greater than the activation thresholds of myelinated Abeta-neurons (Chao et al., 2020). It is possible that certain electrophysiological features of C-type neurons unaccounted for in previous computational models could reduce activation thresholds to ranges comparable to the thresholds of myelinated neurons. For example, Nav1.8 sodium channels, which underlie most of the sodium current during the upstroke of action potentials in some C-neurons, have been shown to be distributed in clusters along the axons of C-type neurons forming so-called “micro-nodes” (Pristerà et al., 2012). In this study, we developed a computational model to investigate the impact of Nav1.8-channel clustering on the threshold for action potential generation in nonmyelinated axons.

ID: 194317 Prolonged Dorsal Root Ganglion (DRG) Trial Adequately Treats Neuropathic Pain Due to Malignant Lumbosacral Mass

63-year-old female with PMH significant for Stage 1a endometrial adenocarcinoma s/p robotic total hysterectomy, had a fall 2 months prior to presentation, with subsequent development of left gluteal and labial numbness. She presented with subacute onset of urinary retention, constipation, weight loss, and radiating left lower extremity pain associated with dysesthesia and impaired gait. Conservative measures were ineffective (combination of NSAIDs, opioids and gabapentin). Typically, the diagnosis of Lumbosacral plexopathy (LSP) requires a thorough clinical evaluation due to a wide differential. However, our patient’s diagnosis was rather brisk due to an aggressive carcinoma causing severe localized pain. In cases of tumor compression, the L4-S1 segment is commonly affected (>50% of cases) followed by L1-L4 segment (31%) and pan-plexopathy (about 10%). At 42-month follow-up, 86% of patients diagnosed with malignancy-induced LS plexopathy had expired. DRG stimulation is approved for CRPS, persistent post-surgical pain syndrome, and peripheral neuropathy for T10-below. To our knowledge, this is the first report of successful application of DRG stimulation trial in the acute malignant pain crisis and palliative care setting.

ID: 207859 Dorsal Root Ganglion Stimulation for Refractory Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a challenging complication of many chemotherapeutic regimens. It is conventionally managed with antidepressants, antiepileptics, and adjuvants [1]. Neuromodulation, such as dorsal root ganglion (DRG) stimulation, is emerging as a potential treatment for refractory cases. First-line chemotherapy for multiple myeloma includes multiple CIPN-associated agents; however, the utility of DRG stimulation has not yet been described in this setting.