Dorsal Root Ganglion Stimulation Research Articles

Spinal Neuromodulation for Peripheral Arterial Disease of Lower Extremities: A Ten-Year Retrospective Analysis.

This long-term retrospective study evaluated the survival and amputation outcome of subjects who received neuromodulation therapy for the management of peripheral arterial disease (PAD). The study reviews the health data of a single cohort of 51 patients who received spinal neuromodulation (spinal cord stimulation [SCS] or dorsal root ganglion stimulation [DRG-S]) for PAD from 2007 to 2022 in a single German center. Survival rate and major amputation rate were determined. Pain, quality of life, walking distance, and opioid usage were assessed before implantation (baseline), one, six, and 12 months (M) after implantation, and then annually (during a follow-up visit). Implant-related complications also were documented. In total, 51 patients (37 men [mean age 68.9± 10.2 years], 14 women [mean age (68.7± 14.6 years]) underwent SCS (n= 49) or DRG-S (n= 2) implantation owing to persistent ischemic pain. The follow-up mean years± SD is 4.04± 2.73. At baseline, patients were classified as Rutherford's category 3 (n= 23), category 4 (n= 15) or category 5 (n= 9). At 24 M, 42 of 47 patients did not require a major amputation after the implant. All the patients reported nearly complete pain relief from pain at rest. A total of 75% of patients were able to walk >200 m, and 87% of patients who used opioids at baseline were off this medication at 24 M. Overall, 93% of patients reported an improvement in their overall health assessment. These improved outcomes were sustained through years three to 10 for patients who have reported outcomes. Our single-center data support the efficacy of spinal neuromodulation for improvements in limb salvage, pain relief, mobility, and quality of life. The data also show that neuromodulative therapy has a long-term therapeutic effect in patients with chronic limb pain with Rutherford category 3, 4, and 5 PAD.

ID: 329728 Efficacy and Safety of Cervical and Thoracic Dorsal Root Ganglion Stimulation Therapy at 24 Months

ID: 329728 Efficacy and Safety of Cervical and Thoracic Dorsal Root Ganglion Stimulation Therapy at 24 Months

The effects of neuron morphology and spatial distribution on the selectivity of dorsal root ganglion stimulation

Objective.For prosthesis users, sensory feedback that appears to come from the missing limb can improve function, confidence, and phantom limb pain. Numerous pre-clinical studies have considered stimulation via penetrating microelectrodes at the dorsal root ganglion (DRG) as a potential approach for somatosensory neuroprostheses. However, to develop clinically translatable neuroprosthetic devices, a less invasive approach, such as stimulation via epineural macroelectrodes, would be preferable. This work explores the feasibility of using such electrodes to deliver focal sensory feedback by examining the mechanisms of selective activation in response to stimulation via epineural electrodes compared with penetrating electrodes.Approach.We developed computational models of the DRG, representing the biophysical properties of the DRG and surrounding tissue to evaluate neural responses to stimulation via penetrating microelectrodes and epineural macroelectrodes. To assess the role of properties such as neuron morphology and spatial arrangement we designed three models, including one that contained only axons (axon only), one with pseudounipolar neurons arranged randomly (random), and one with pseudounipolar neurons placed according to a realistic spatial distribution (realistic).Main results.Our models demonstrate that activation in response to stimulation via epineural electrodes in a realistic model is commonly initiated in the axon initial segment adjacent to the cell body, whereas penetrating electrodes commonly elicit responses in t-junctions and axons. Moreover, we see a wider dynamic range for epineural electrodes compared with penetrating electrodes. This difference appears to be driven by the spatial organization and neuron morphology of the realistic DRG.Significance.We demonstrate that the anatomical features of the DRG make it a potentially effective target for epineural stimulation to deliver focal sensations from the limbs. Specifically, we show that epineural stimulation at the DRG can be highly selective thanks to the neuroanatomical arrangement of the DRG, making this a promising approach for future neuroprosthetic development.

Procedural interventions for erythromelalgia: A narrative review.

Erythromelalgia is a rare disorder characterized by episodic burning pain with redness and warmth of the extremities. Topical and systemic medications are the mainstay of management. We reviewed the published evidence for using procedural interventions to manage erythromelalgia, including their proposed mechanism of action and possible adverse effects, and included information in this review on epidural infusion, sympathetic ganglion block, sympathectomy, pulsed radiofrequency, spinal cord stimulation, dorsal root ganglion stimulation, brain stimulation, transcranial magnetic stimulation, and botulinum toxin injections. Both successful and unsuccessful outcomes have been reported. Although these procedural interventions extend the therapeutic options for erythromelalgia, the evidence for their use is limited. Case reports and small case series comprise most of the evidence. Based on our review, a multidisciplinary approach to management may be needed for patients with erythromelalgia.

Diabetic peripheral neuropathy and neuromodulation techniques: a systematic review of progress and prospects.

Neuromodulation for diabetic peripheral neuropathy represents a significant area of interest in the management of chronic pain associated with this condition. Diabetic peripheral neuropathy, a common complication of diabetes, is characterized by nerve damage due to high blood sugar levels that lead to symptoms, such as pain, tingling, and numbness, primarily in the hands and feet. The aim of this systematic review was to evaluate the efficacy of neuromodulatory techniques as potential therapeutic interventions for patients with diabetic peripheral neuropathy, while also examining recent developments in this domain. The investigation encompassed an array of neuromodulation methods, including frequency rhythmic electrical modulated systems, dorsal root ganglion stimulation, and spinal cord stimulation. This systematic review suggests that neuromodulatory techniques may be useful in the treatment of diabetic peripheral neuropathy. Understanding the advantages of these treatments will enable physicians and other healthcare providers to offer additional options for patients with symptoms refractory to standard pharmacologic treatments. Through these efforts, we may improve quality of life and increase functional capacity in patients suffering from complications related to diabetic neuropathy.

Radiofrequency stimulation of the dorsal root ganglion as a diagnostic tool for radicular pain syndromes: six representative cases

BackgroundWe discuss the diagnostic benefit of pulsed radiofrequency (PRF) of the dorsal root ganglion (DRG) in a case series of patients with different pathologies. We expand the diagnostic potential of DRG stimulation beyond paresthesia mapping by using DRG stimulation to help determine the role of the DRG in the patient’s pain and narrow down the etiology. In some cases, DRG stimulation was also part of the treatment plan.MethodsSix patients underwent DRG radiofrequency as a diagnostic/therapeutic step before considering implantation of a DRG neurostimulator. First, patients underwent a basic bedside neurological evaluation. Next, an electrode was placed in the epidural space through the sacral hiatus or between vertebral laminae. Then, sensory stimulation was applied at 50 Hz and gradually increased from 0.1 V until the patient reported paresthesia or until a maximum intensity of 2 V was reached. Patients were asked to describe where the stimulation was felt and outline the anatomical area the paresthesia covered. Then a motor stimulation was applied at 2 Hz until muscle twitching was reported by the patient or observed by the physician.ResultsThe information obtained helped diagnose the type of lesion as principally preganglionic, ganglionic, or postganglionic. This information guided patient management.ConclusionPRF of the DRG can provide valuable diagnostic information and is a useful step before ganglionic electrode implantation. In all cases, PRF of the DRG provided valuable diagnostic information and guided management options.

Long-term explantation risk in patients with chronic pain treated with spinal cord or dorsal root ganglion stimulation

ObjectiveTo investigate long-term explantation risks and causes for the explantation of neuromodulation devices for the treatment of chronic pain from different manufacturers.MethodsThis retrospective analysis included patients implanted with a system...

A Review of Remote Monitoring in Neuromodulation for Chronic Pain Management.

Neuromodulation techniques have emerged as promising strategies for managing chronic pain. These techniques encompass various modalities of nerve stimulation, including Spinal Cord Stimulation (SCS), Dorsal Root Ganglion Stimulation (DRG-S), and Peripheral Nerve Stimulation (PNS). Studies consistently demonstrate significant improvements in pain intensity, quality of life, and reduced opioid usage among patients treated with these modalities. However, neuromodulation presents challenges, such as the need for frequent in-person follow-up visits to ensure proper functionality of the implanted device. Our review explored factors impacting compliance in current neuromodulation users and examined how remote monitoring can mitigate some of these challenges. We also discuss outcomes of recent studies related to remote monitoring of neuromodulation. While remote monitoring capabilities for neuromodulation devices is an emerging development, there are promising results supporting its role in improving outcomes for chronic pain patients. Higher patient satisfaction, improved pain control, and reduced caretaker burdens have been observed with the use of remote monitoring. This review discusses the current challenges with neuromodulation therapy and highlights the role of remote monitoring. As the field continues to evolve, understanding the importance of remote monitoring for neuromodulation is crucial for optimizing pain management outcomes.

Tonic Stimulation of Dorsal Root Ganglion Results in Progressive Decline in Recruitment of Aα/β-Fibers in Rats

ObjectivesIn this study, we aimed to characterize the recruitment and maintenance of action potential firing in Aα/β-fibers generated during tonic dorsal root ganglion stimulation (DRGS) applied over a range of clinically relevant stimulation parameters. Materials and MethodsWe delivered electrical stimulation to the L5 dorsal root ganglion and recorded antidromic evoked compound action potentials (ECAPs) in the sciatic nerve during DRGS in Sprague Dawley rats. We measured charge thresholds to elicit ECAPs in Aα/β-fibers during DRGS applied at multiple pulse widths (50, 150, 300, 500 μs) and frequencies (5, 20, 50, 100 Hz). We measured the peak-to-peak amplitudes, latencies, and widths of ECAPs generated during 180 seconds of DRGS, and excitation threshold changes to investigate potential mechanisms of ECAP suppression. ResultsTonic DRGS produced ECAPs in Aα/β-fibers at charge thresholds below the motor threshold. Increasing the pulse width of DRGS led to a significant increase in the charge required to elicit ECAPs in Aα/β-fibers, while varying DRGS frequency did not influence ECAP thresholds. Over the course of 180 seconds, ECAP peak-to-peak amplitude decreased progressively in a frequency-dependent manner, where 5- and 100-Hz DRGS resulted in 22% and 87% amplitude reductions, respectively, and ECAP latencies increased from baseline measurements during DRGS at 10, 20, 50, and 100 Hz. Regardless of DRGS frequency, ECAP amplitudes recovered within 120 seconds after turning DRGS off. We determined that ECAP suppression may be attributed to increasing excitation thresholds for individual fibers during DRGS. Following 180 seconds of DRGS, an average of 7.33% increase in stimulation amplitude was required to restore the ECAP to baseline amplitude. ConclusionsDRGS produces a progressive and frequency-dependent reduction in ECAP amplitude that occurs within and above the frequency range used clinically to relieve pain. If DRGS-mediated analgesia relies on Aβ-fiber activation, then the frequency or duty cycle of stimulation should be set to the lowest effective level to maintain sufficient activation of Aβ-fibers.

Advances in Spinal Neuromodulation for Chemotherapy-induced Peripheral Neuropathy.

Chemotherapy-induced peripheral neuropathy (CIPN) continues to be a major source of chronic morbidity in patients with cancer. Current treatment options and efficacy are limited; thus, there is a need to investigate more effective therapeutic options. Spinal neuromodulation including dorsal column spinal cord stimulation (SCS) and dorsal root ganglion stimulation (DRG-S) are being explored for these patients. The purpose of this narrative review was to critically summarize and evaluate the advancements that have been made in utilizing SCS and DRG-S for CIPN. A thorough literature search was conducted using PubMed for any research on patients with CIPN who underwent DRG-S or SCS. Studies involving patients with general cancer-related pain were not included. Only articles that were published in English, had original, extractable data, and were available on or before August 1, 2023, were included. This study evaluated twelve studies with a total of 13 patients that reported using SCS for CIPN and four studies with a total of 12 patients that reported using DRG-S for CIPN. Many of the studies demonstrated that DRG-S or SCS can assist in reducing opioid consumption, lowering pain scores, and improving sensory deficits. DRG-S and SCS have the potential to improve symptoms and lower medication usage in patients suffering from CIPN. Spinal neuromodulation could be considered as an alternative therapy for patients with persistent symptoms.

Low-frequency dorsal root stimulation is effective for various pain etiologies and pain locations.

Dorsal root ganglion stimulation (DRG-S) has emerged as a novel therapeutic approach for managing chronic neuropathic pain. This study aims to compare the effectiveness of 4-20 Hz DRG-S through a retrospective analysis of a cohort of 28 patients with various neuropathic pain etiologies and pain locations. Patient responses to both stimulation frequencies were examined using the Numeric Rating Scale (NRS) and Patient Global Impression of Change (PGIC) assessments. Factors such as patient preference and satisfaction were also evaluated. The results indicate that 4 Hz DRG-S is not only as effective as 20 Hz stimulation but may also surpass it. Among the 28 patients, 26 assessed 4 Hz stimulation to be at least as effective as 20 Hz, with the majority (22 out of 26) considering 4 Hz stimulation superior. After trying 4 Hz stimulation, 24 out of 28 patients chose it over 20 Hz, while two patients opted for a combination of both settings. Only two patients reverted to their original 20 Hz stimulation program. A statistically significant pain reduction of 24% was observed when comparing the effects of 4 Hz versus 20 Hz. The study highlights the broader applicability of low-frequency DRG-S, extending its benefits beyond the realm of low back pain. Patients with diverse pain etiologies and locations experienced comparable positive outcomes, suggesting that the advantages of low-frequency stimulation are not confined to specific pain types or locations. This study emphasizes the potential of 4 Hz DRG-S as a valuable alternative to the standard 20 Hz stimulation. Although the exact mechanisms require further investigation, the observed clinical benefits and patient preferences for low-frequency stimulation suggest its viability across diverse pain indications and locations. Additional research is necessary to substantiate these findings and assess the durability and economic implications of low-frequency DRG-S.

Synergistic neuromodulation therapy for persistent spinal pain: a proof-of-concept trial on the use of spinal cord and dorsal root ganglion stimulation.

Persistent Spinal Pain Syndrome type 2 (PSPS-T2) poses a significant clinical challenge, demanding innovative therapeutic interventions. The integration of Spinal Cord Stimulation (SCS) and Dorsal Root Ganglion Stimulation (DRG-S) is emerging as a potent synergistic strategy for comprehensive pain management. This single patient-blind proof of concept (POC) trial explores the efficacy and synergistic potential of combined SCS and DRG-S in a patient with refractory PSPS-T2. A 45-year-old male with intractable PSPS-T2 underwent a unique, methodically structured study, involving three treatment phases: Phase A with SCS alone, Phase B with DRG-S alone, and Phase C The patient, blinded to the treatment modalities, provided pain assessments using the Visual Analogue Scale (VAS) and Douleur Neuropathique 4 Questions (DN4) conducted by clinical investigators at each phase. Baseline pain scores were ten and nine, respectively. Distinct responses were noted across the phases. Phase A demonstrated moderate pain relief, while Phase B offered further pain intensity reduction. However, Phase C, combining both strategies, yielded the most significant improvement, remarkably enhancing the patient's quality of life and functional capacity. This POC trial underscores the synergistic potential of SCS and DRG-S in managing complex cases of PSPS-T2, suggesting a paradigm shift towards integrated neuromodulation strategies for enhanced pain control. The development of dual intent implantable pulse generators (IPGs) capable of offering combination therapy simultaneously might be effective for pain management in select cases. The significant pain reduction and functional improvement observed advocate for further research in dual neuromodulation therapies. IRB 20190536.

Comparison of the efficacy of spinal cord stimulation and dorsal root ganglion stimulation in the treatment of painful diabetic peripheral neuropathy: a prospective, cohort-controlled study.

The aim of this study was to compare the clinical outcomes of spinal cord stimulation (SCS) and dorsal root ganglion stimulation (DRG-S) in the treatment of painful diabetic peripheral neuropathy (PDPN). In this prospective cohort study, 55 patients received dorsal column spinal cord stimulation (SCS group) and 51 patients received dorsal root spinal cord stimulation (DRG-S group). The primary outcome was a Numerical Rating Scale (NRS) remission rate of ≥50%, and secondary outcomes included the effects of SCS and DRG-S on quality of life scores (EQ-5D-3L), nerve conduction velocity, and HbA1c, respectively. The percentage of NRS remission rate ≥ 50% at 6 months was 80.43 vs. 79.55%, OR (95% CI): 1.06 (0.38-2.97) in the SCS and DRG-S groups, respectively, and the percentage of VAS remission rate ≥ 50% at 12 months was 79.07 vs. 80.95%, OR (95% CI): 0.89 (0.31-2.58). Compared with baseline, there were significant improvements in EQ-5D and EQ-VAS at 6 and 12 months (p < 0.05), but there was no difference in improvement between the SCS and DRG-S groups (p > 0.05). Nerve conduction velocities of the common peroneal, peroneal, superficial peroneal, and tibial nerves were significantly improved at 6 and 12 months compared with the preoperative period in both the SCS and PND groups (p < 0.05). However, at 6 and 12 months, there was no difference in HbA1c between the two groups (p > 0.05). Both SCS and DRG-S significantly improved pain, quality of life, and lower extremity nerve conduction velocity in patients with PDPN, and there was no difference between the two treatments at 12 months.

Computational modeling of dorsal root ganglion stimulation using an Injectrode

Objective. Minimally invasive neuromodulation therapies like the Injectrode, which is composed of a tightly wound polymer-coated Platinum/Iridium microcoil, offer a low-risk approach for administering electrical stimulation to the dorsal root ganglion (DRG). This flexible electrode is aimed to conform to the DRG. The stimulation occurs through a transcutaneous electrical stimulation (TES) patch, which subsequently transmits the stimulation to the Injectrode via a subcutaneous metal collector. However, it is important to note that the effectiveness of stimulation through TES relies on the specific geometrical configurations of the Injectrode-collector-patch system. Hence, there is a need to investigate which design parameters influence the activation of targeted neural structures. Approach. We employed a hybrid computational modeling approach to analyze the impact of Injectrode system design parameters on charge delivery and neural response to stimulation. We constructed multiple finite element method models of DRG stimulation, followed by the implementation of multi-compartment models of DRG neurons. By calculating potential distribution during monopolar stimulation, we simulated neural responses using various parameters based on prior acute experiments. Additionally, we developed a canonical monopolar stimulation and full-scale model of bipolar bilateral L5 DRG stimulation, allowing us to investigate how design parameters like Injectrode size and orientation influenced neural activation thresholds. Main results. Our findings were in accordance with acute experimental measurements and indicate that the minimally invasive Injectrode system predominantly engages large-diameter afferents (Aβ-fibers). These activation thresholds were contingent upon the surface area of the Injectrode. As the charge density decreased due to increasing surface area, there was a corresponding expansion in the stimulation amplitude range before triggering any pain-related mechanoreceptor (Aδ-fibers) activity. Significance. The Injectrode demonstrates potential as a viable technology for minimally invasive stimulation of the DRG. Our findings indicate that utilizing a larger surface area Injectrode enhances the therapeutic margin, effectively distinguishing the desired Aβ activation from the undesired Aδ-fiber activation.

Dorsal Root Ganglion Stimulation Relieves Chronic Neuropathic Pain Along With a Decrease in Cortical γ Power

BackgroundStimulation of dorsal root ganglion (DRG) is an ideal neuromodulative intervention, providing pain relief in localized chronic pain conditions because γ-band oscillations reflect the intensity of ongoing chronic pain in patients affected. ObjectiveWe aimed to observe the role of cortical γ-band power associated with the relief of chronic neuropathic pain through DRG stimulation (DRGS). Materials and MethodsWe examined nine patients (two women, mean age 56.8 years; range, 36–77 years) diagnosed with chronic neuropathic pain who underwent DRGS therapy. We used the numeric rating scale (NRS) on the painful limb and simultaneously recorded the electroencephalography to assess the broadband γ power. Assessments were conducted on the first day and on the seventh day after implantation of the DRGS system and then compared and correlated with the results of the NRS. ResultsThe NRS scores showed a significant decrease from the first day to the seventh day (p = 0.007). The resting-state γ power revealed a significant decrease (p = 0.021) between 30 and 45 Hz, recorded through the central electrode contralateral to the painful limb from the first day (mean [M] = 0.46, SD = 0.25) to the seventh day (M = 0.31, SD = 0.12) after DRGS. There was no significant change in the resting-state γ-band power recorded through the central electrode ipsilateral to the painful limb. However, we found a positive correlation in the γ-band power (rs = 0.628, p = 0.005) with the NRS rating. ConclusionsA lateralized decrease in broadband γ power may be considered further evidence supporting a reduction in the hyperexcitability of the nociceptive system in response to DRGS therapy. In the future, γ-band power could serve as a biomarker for assessing the efficacy of DRGS during the seven-day test phase preceding the implantation of the DRGS system.

Mechanisms of Action of Dorsal Root Ganglion Stimulation.

The dorsal root ganglion (DRG) serves as a pivotal site for managing chronic pain through dorsal root ganglion stimulation (DRG-S). In recent years, the DRG-S has emerged as an attractive modality in the armamentarium of neuromodulation therapy due to its accessibility and efficacy in alleviating chronic pain refractory to conventional treatments. Despite its therapeutic advantages, the precise mechanisms underlying DRG-S-induced analgesia remain elusive, attributed in part to the diverse sensory neuron population within the DRG and its modulation of both peripheral and central sensory processing pathways. Emerging evidence suggests that DRG-S may alleviate pain by several mechanisms, including the reduction of nociceptive signals at the T-junction of sensory neurons, modulation of pain gating pathways within the dorsal horn, and regulation of neuronal excitability within the DRG itself. However, elucidating the full extent of DRG-S mechanisms necessitates further exploration, particularly regarding its supraspinal effects and its interactions with cognitive and affective networks. Understanding these mechanisms is crucial for optimizing neurostimulation technologies and improving clinical outcomes of DRG-S for chronic pain management. This review provides a comprehensive overview of the DRG anatomy, mechanisms of action of the DRG-S, and its significance in neuromodulation therapy for chronic pain.

Novel Implantation Technique for Thoracoabdominal Peripheral Nerve Stimulation via a Transversus Abdominal Plane Approach for Treatment of Chronic Abdominal Pain.

Chronic abdominal pain (CAP) is a common and challenging to treat condition with a global prevalence of up to 25%. Despite extensive evaluation, approximately 40% of patients with CAP have an unknown diagnosis. Medications may be ineffective, and surgery is rarely indicated. Interventional treatment including sympathetic blocks, sympathetic neurolysis, and transversus abdominal plane (TAP) blocks may be an option, but their efficacy can wane over time. Neuromodulation has emerged as an option for these patients, as there is evidence of success with dorsal column spinal cord and dorsal root ganglion (DRG) stimulation. Peripheral nerve stimulation (PNS) may be an alternative option, particularly in higher risk patients or in patients for whom neuraxial access may be unsafe or too technically challenging. Thoracoabdominal nerve peripheral nerve stimulation via a TAP approach may be more specifically targeted in comparison to dorsal column or DRG stimulation. In this short report, we detail a technique that the authors have successfully used for thoracoabdominal nerve PNS via a TAP approach for management of CAP. This article describes a novel medial to lateral ultrasound guided thoracoabdominal nerve PNS via a TAP approach technique for lead placement and implantation. A medial to lateral ultrasound guided TAP approach as described to successfully implant percutaneous thoracoabdominal nerve PNS leads for management of CAP. The thoracoabdominal nerve PNS via a TAP approach lead placement technique noted in this report has been used as a means for management of CAP utilizing peripheral neuromodulation. Here, we present a short report detailing a potential technique for PNS utilization for management of CAP. Further studies are needed to validate the safety and efficacy of this therapy modality, although the authors have found it to be a viable management option for patients with medically refractory neuropathic CAP.

Phantom limb pain: actual concepts of pathophysiology and treatment methods from the standpoint of evidence-based medicine

Rationale. Despite a large number of studies on the effectiveness of various pharmacological and non- pharmacological therapies, PLP treatment tactics have not yet been developed, which is largely due to the complex mechanism of the formation of this pathology. Although PLP is classified as neuropathic pain, standard methods of neuropathic pain therapy are not always effective for this syndrome. To optimize the regimens of existing methods of PLP treatment, as well as the search and clinical trials of new therapeutic approaches, it is necessary to take into account the currently available evidence base.Material and methods. Our analysis included publications on phantom pain treatment methods with a high level of evidence (randomized controlled trials, systematic reviews and meta-analyses). Literature search was performed in Medline PubMed and eLIBRARY systems.Results. The review provides an evidence base for pharmacotherapy methods (opioids, NMDA-receptor antagonists, tricyclic antidepressants, anticonvulsants, local anesthetics), for methods based on the phantom illusion (mirror therapy, motion representation, virtual reality), for non-invasive (transcutaneous electrical neurostimulation, transcranial magnetic stimulation, transcranial electrical stimulation) and invasive (deep brain stimulation, motor cortex stimulation, spinal cord stimulation, dorsal root ganglion stimulation) neuromodulation. Data on the most studied dosing regimens of different methods of pharmacological and non-pharmacological therapy are presented.

Application of multidisciplinary team conference for neuromodulation candidates facilitates patient selection and optimization.

Psychological evaluation is required by insurance companies in the United States prior to proceeding with a spinal cord stimulation or a dorsal root ganglion stimulation trial. Since January 2017, we implemented a Multidisciplinary Team Conference for Neuromodulation in our center to facilitate the collaboration between pain physicians and psychologists and to optimize screening of neuromodulation candidates. This study aims to report the impact of this team conference on improvement of neuromodulation outcome in our center. Appropriateness of neuromodulation were discussed in the team conference after initial visit with the pain specialist and psychological evaluation. For this study, we prospectively and retrospectively collected data on neuromodulation candidates who went through the team conference and those who did not as controls. We discussed 461 patients in the team conference sessions from January 2017 to July 2023. Out of these, a spinal cord stimulator or a dorsal root ganglion stimulator trial was performed in 164 patients with 80.5% (132 cases) trial success rate leading to 140 implants. Out of these implants, 26 (18.6%) explanted and 21 (15%) required revision in 41 (29.3%) patients. We performed neuraxial neuromodulation trial for 70 patients without going through the team conference from January 2016 to July 2023 with a trial success rate of 45.7% (32 cases). In this group, 7 (21.9%) and 6 (18.8%) patients underwent explant and revision. The differences between the groups were statistically significant for trial success rate (odds ratio of 4.9 with p-value of <0.01) but not for explant (odds ratio of 0.8 with p-value of 0.627) or revision (odds ratio of 0.8 with p-value of 0.595). Implementing Multidisciplinary Team Conference increased trial success rate in our center. Team conference provides therapeutic benefit for patients, and also provides the opportunity for an educational discussion for trainees.

Electrical dorsal root ganglion stimulation (DRGS) for the treatment of refractory postherpetic neuralgia

A retrospective analysis of the technique and results of implantation of a permanent device for stimulating the spinal ganglia in patients with refractory PHN at the Burdenko Neurosurgical Center. The study was conducted in 7 patients (5 men, 2 women) with refractory PHN in the period from 2018 to 2020. The age of the patients ranged from 57 to 84 years (average age 74±8.4). All patients were implanted with Boston systems (Precision or Spectra versions). Stimulation parameters: pulse width - 120-210 μs, frequency - 30-130 Hz, amplitude at the lower limit of the appearance of paresthesia with the possibility of increasing with increased pain up to 5 mA. The position of the electrode depended on the location of the pain. All systems were implanted under X-ray guidance. The duration of follow-up observation was more than 2.5 years. The average pain intensity one year after treatment was 3.42±2.45 points on the visual analogue scale (VAS) (a 62.3% decrease in intensity compared to baseline). In 3 (42.8%) patients, the result was characterized by us as «excellent» (intensity according to VAS decreased by 75% or more), in 1 (14.2%) - as «good» (intensity according to VAS decreased by 50-74%), in 1 (14.2%) - as «moderate» (VAS intensity decreased by 25-49% and in 2 (28.5%) as «unsatisfactory» (VAS intensity decreased by less than 25%, or postoperative complications occurred). Given the complicated nature of PHN, the use of dorsal ganglion stimulation appears to be a promising and innovative treatment approach. Further research is needed to introduce this technique into clinical practice for the treatment of patients suffering from PHN.