Lead migration and fracture rate in dorsal root ganglion stimulation using anchoring and non-anchoring techniques: A multicenter pooled data analysis

The Neurostimulation Appropriateness Consensus Committee (NACC)®: Recommendations for Spinal Cord Stimulation Long-term Outcome Optimization and Salvage Therapy

INTRODUCTION

The International Neuromodulation Society (INS) has recognized a need to establish best practices for optimizing implantable devices and salvage when ideal outcomes are not realized. This group has established the Neurostimulation Appropriateness Consensus Committee (NACC)® to offer guidance on matters needed for both our members and the broader community of those affected by neuromodulation devices.

MATERIALS AND METHODS

The executive committee of the INS nominated faculty for this NACC® publication on the basis of expertise, publications, and career work on the issue. In addition, the faculty was chosen in consideration of diversity and inclusion of different career paths and demographic categories. Once chosen, the faculty was asked to grade current evidence and along with expert opinion create consensus recommendations to address the lapses in information on this topic.

RESULTS

The NACC® group established informative and authoritative recommendations on the salvage and optimization of care for those with indwelling devices. The recommendations are based on evidence and expert opinion and will be expected to evolve as new data are generated for each topic.

CONCLUSIONS

NACC® guidance should be considered for any patient with less-than-optimal outcomes with a stimulation device implanted for treating chronic pain. Consideration should be given to these consensus points to salvage a potentially failed device before explant.

Case report: Dorsal root ganglion stimulator lead fracture

BACKGROUND

One of the unique advances in neuromodulation for chronic pain has been spinal cord stimulators (SCS) and dorsal root ganglion stimulators (DRG-S). These devices have aided in conditions such as neuropathic pain, complex regional pain syndromes, failed back surgery, and peripheral neuropathies. With these benefits, however, complications from implantable stimulators have included lead fractures and migration. The authors reviewed a lead migration, kinking, and subsequent fracture event involving a patient with complex regional pain syndrome (CRPS) II, who was treated with a DRG-S.

CASE PRESENTATION

The case report follows this patient, from their past medical history to assessment of appropriate qualifications for neuromodulation, to successful surgical placement, to follow-up care. The authors further monitored assessment of inefficacy of pain relief, and identification of lead migration and kinking through imaging. In the process of removal, due to lead stress, lead fracturing occurred. After lead removal, the leads were fully replaced, and the patient was followed up and experienced improved pain relief.

CONCLUSION

The case report assesses probable mechanisms of lead fracture and considerations for physicians for future assessment and triage of neuromodulation efficacy.

Lead migration rate in dorsal root ganglion stimulation using lead anchoring techniques: A follow-up study

BACKGROUND

Lead anchoring has previously been shown to reduce the rate of dorsal root ganglion stimulation (DRG-S) lead migration. The aim of this study was to assess longer-term follow-up and consistency of lead migration prevention with lead anchoring in a new cohort of patients.

METHODS

We performed a retrospective chart review from September 2017 to November 2022 of all patients who had DRG-S implants at our institute to identify the number of lead migrations that occurred over this period. The first cohort consisted of patients reported on in a previous publication (implanted from September 2017 through September 2020) subdivided into unanchored or anchored lead groups. The second cohort consisted of patients implanted during or after October 2020 who were not previously reported on for whom leads were anchored using silastic anchoring only.

RESULTS

At the November 2022 data cutoff, in the initial cohort, 8 migrations had occurred in unanchored leads over an average follow-up of 49 months, equating to a migration rate of 9.1% per lead. Patients with anchored leads in the initial cohort experienced 2 migrations over an average follow-up of 38 months (0.7% migration rate per lead). There were no new lead migrations in these groups over the extended follow-up reported here. The migration rate in the new cohort was similar, with 1 migration over an average follow-up of 13 months (0.5% migration rate per lead).

CONCLUSION

These results underscore the necessity of anchor placement during DRG-S lead implantation to prevent lead migration.

Dorsal Root Ganglion Stimulation to Treat Chronic Shoulder Pain: A Case Report

A 67-year-old man presented with severe 9 of 10 intractable pain of the left shoulder joint after arthroplasty and revision surgeries, with associated weakness, atrophy, and limited range of motion in all directions. Dorsal root ganglion stimulation (DRG-S) at the left C4, C5, and C6 levels was used after failed conservative and interventional measures, resulting in significant improvement in pain, function, and quality of life measures through 6 months postimplantation. Larger studies should examine if DRG-S is effective in treating chronic arthritic joint pain as well as chronic postsurgical pain of the shoulder that is not predominantly neuropathic.

Dorsal root ganglion stimulation for the treatment of joint pain with predominantly nociceptive characteristics: A case series

INTRODUCTION

Dorsal root ganglion stimulation (DRG-S) has recently emerged as a novel therapy in neuromodulation that demonstrated a higher rate of success than spinal cord stimulation (SCS) in a prospective, head-to-head randomized comparative trial to treat complex regional pain syndrome (CRPS) and causalgia. In contrast to SCS, DRG-S also shows promise in treating conditions that are not purely neuropathic such as axial low back pain, which has a prominent nociplastic pain component. It is not known to what extent the effectiveness of DRG-S for such indications is due to effective treatment of the neuropathic pain component versus the effects of DRG-S on mechanical pain. Although rarely studied, reporting outcomes of DRG-S to treat predominantly mechanical/nociceptive pain may help point toward expanding the utility of this therapy. Here, we present five cases of refractory mechanical pain treated with DRG-S.

METHODS

A retrospective analysis of all patients who underwent a successful DRG-S trial and implant between September 2017 and September 2021 at our institute was performed. Patients who had intractable joint pain without strong evidence of neuropathic pain were included in this case series. The Budapest criteria for CRPS, the Douleur Neuropathique 4 Questions (DN4) survey, or a definable nerve injury were used to determine the presence of neuropathic pain. Baseline assessments for pain (Numeric Rating Scale [NRS]), function (Oswestry Disability Index [ODI]), quality of life (EuroQol-5 Dimension [EQ-5D]), and other applicable joint surveys were extracted from pre-trial baseline and follow-up appointments.

RESULTS

Five patients were identified and included. Patient diagnoses consisted of refractory joint pain of the hip, knee, or ankle. Mean NRS pain scores improved by 74% from 9.2 at baseline to 2.4 at the last follow-up (mean = 28 months post-implant). From baseline to the last follow-up, mean ODI scores improved by 65% from 66 to 23 and EQ-5D scores more than doubled from an average of 0.371 to 0.797.

CONCLUSION

This clinical report illustrates the potential utility DRG-S has in treating pain that clinically presents as predominantly refractory mechanical joint pain without a significant neuropathic component. The physiological reasons for our observations may be that DRG-S is able to directly influence the conduction of nociceptive signaling at the DRG and within the spinal cord. Further investigations are warranted to determine if DRG-S is a potential treatment option for chronic mechanical pain.

Best Practices for Dorsal Root Ganglion Stimulation for Chronic Pain: Guidelines from the American Society of Pain and Neuroscience

With continued innovations in neuromodulation comes the need for evolving reviews of best practices. Dorsal root ganglion stimulation (DRG-S) has significantly improved the treatment of complex regional pain syndrome (CRPS), and it has broad applicability across a wide range of other conditions. Through funding and organizational leadership by the American Society for Pain and Neuroscience (ASPN), this best practices consensus document has been developed for the selection, implantation, and use of DRG stimulation for the treatment of chronic pain syndromes. This document is composed of a comprehensive narrative literature review that has been performed regarding the role of the DRG in chronic pain and the clinical evidence for DRG-S as a treatment for multiple pain etiologies. Best practice recommendations encompass safety management, implantation techniques, and mitigation of the potential complications reported in the literature. Looking to the future of neuromodulation, DRG-S holds promise as a robust intervention for otherwise intractable pain.

An Anatomy-Informed, Novel Technique for S1 Dorsal Root Ganglion Stimulation Lead Placement

Objective

A heightened and organized understanding of sacral anatomy could potentially lead to a more effective and safe method of dorsal root ganglion stimulation (DRG-S) lead placement. The aim of this technical note is to describe a standardized access method for S1 DRG-S lead placement.

Design

Technical note.

Methods

The described approach utilizes alignment of the lumbosacral prominence and is measurement-based, allowing for standardized sacral access, even when visualization is suboptimal. The medial-to-lateral needle trajectory is designed to limit interaction with the sensitive neural structures and allows for a more parallel orientation of the lead to the DRG and nerve root.

Conclusions

The described technique potentially improves the safety of S1 DRG-S lead placement. The parallel lead orientation to the DRG may also increase efficacy while lowering energy requirements.

The Neurostimulation Appropriateness Consensus Committee (NACC): Recommendations for Surgical Technique for Spinal Cord Stimulation

INTRODUCTION

The field of neurostimulation for the treatment of chronic pain is a rapidly developing area of medicine. Although neurostimulation therapies have advanced significantly as a result of technologic improvements, surgical planning, device placement, and postoperative care are of equal importance to optimize outcomes. This Neurostimulation Appropriateness Consensus Committee (NACC) project intends to provide evidence-based guidance for these often-overlooked areas of neurostimulation practice.

MATERIALS AND METHODS

Authors were chosen based on their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from the last NACC publication in 2017 to the present. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on evidence strength and consensus when evidence was scant.

RESULTS

This NACC project provides guidance on preoperative assessment, intraoperative techniques, and postoperative management in the form of consensus points with supportive evidence. These results are based on grade of evidence, strength of consensus, and expert opinion.

CONCLUSIONS

The NACC has given guidance for a surgical plan that encompasses the patient journey from the planning stage through the surgical experience and postoperative care. The overall recommendations are designed to improve efficacy and the safety of patients undergoing these neuromodulation procedures and are intended to apply throughout the international community.

A Paramedian Approach for Dorsal Root Ganglion Stimulation Placement Developed to Limit Lead Migration and Fracture

INTRODUCTION

Dorsal root ganglion stimulation (DRG-S), has demonstrated superiority in the treatment of complex regional pain syndrome and causalgia. Lead migration and fracture impact DRG-S therapeutic stability. Lead anchoring reduces DRG-S lead migration without increasing lead fracture. Lead fracture may be related to lead entrapment in the superficial fascial plane. A novel medialized approach for lead placement and anchoring is presented to address these issues.

METHODS

We suggest an alternative technique for implanting percutaneous DRG-S leads at the T10-L5 levels.

RESULTS

A novel medialized ipsilateral technique for lead placement and anchoring for single, bilateral, and adjacent segment placement is presented. The Tuohy needle puncture site is medial to the pedicle and adjacent to the spinous process, two vertebral levels caudad to the target foramen. Trajectory is maintained in the sagittal plane, to access the caudad interlaminar space near the midline. This technique allows for ipsilateral or contralateral lead placement. After epidural access, the introducer sheath is rotated toward the targeted foramen and advanced. The guidewire followed by the lead is passed, and once lead position is confirmed, tension 'S' loops are created, followed by anchoring to the deep fascia.

CONCLUSION

We describe a new paramedian technique for DRG-S lead placement. We propose it will decrease DRG-S complication rates through anchoring to reduce migration and by avoiding the fascial planes thought to be responsible for fracture. Long-term outcomes applying our proposed techniques are required for determining the true impact, however, early anecdotal results suggest that these new techniques are favorable.

Single-Center Retrospective Analysis of Device-Related Complications Related to Dorsal Root Ganglion Stimulation for Pain Relief in 31 Patients

INTRODUCTION

Dorsal root ganglion (DRG) stimulation is a form of neuromodulation used to treat neuropathic pain due to a myriad of etiologies. Though this relatively new therapy has been shown to be quite effective, complications associated with the implantation of this therapy have not been well documented.

OBJECTIVES

The primary objective of this study was to describe the device-related complications associated with DRG stimulator implantations.

MATERIALS AND METHODS

This was a single-center retrospective analysis of 31 patients who underwent full implantation of neuromodulation hardware marketed for DRG stimulation. The predefined endpoints included device-related complications associated with DRG implantations, such as hardware failure, explantation procedures, and revision surgery. Additional endpoints included percentage of patients receiving therapy and pain as measured using the visual analog scale (VAS) pain scale at initial, six-month, and 12-month follow-up after hardware implantation.

RESULTS

Thirty-one patients were included out of 42 patients trialed. Baseline VAS in patients was 7.7 (31 patients). At initial follow-up, six-month follow-up, and one-year follow-up, VAS scores were 4.7 (31 patients), 5.3 (20 patients), and 5.5 (13 patients), respectively. Paired t-test between preoperative VAS (mean 7.3) and one-year follow-up VAS (5.5) demonstrated statistical significance (p = 0.027). At initial, six-month, and one-year follow-up, 30/31 (97%), 19/24 (79%), and 18/23 (78%) patients were confirmed to be receiving DRG stimulation therapy after permanent implant. Of the 31 patients who were implanted with a permanent system, 8 (26%) were explanted and an additional 10 (29%) required revision surgery.

CONCLUSION

In this study, we examine the various device-related complications associated with DRG stimulation requiring repeat surgery. High rates of hardware failure, revision surgery, and explantation of stimulators illustrate the need for hardware optimization to improve patient outcomes.