Subcutaneous Peripheral Nerve Stimulation with Inter-lead Stimulation for Axial Neck and Low Back Pain: Case Series and Review of the Literature

Evidence-Based Clinical Guidelines from the American Society of Pain and Neuroscience for the Use of Implantable Peripheral Nerve Stimulation in the Treatment of Chronic Pain

The objective of this peripheral nerve stimulation consensus guideline is to add to the current family of consensus practice guidelines and incorporate a systematic review process. The published literature was searched from relevant electronic databases, including PubMed, Scopus, Cochrane Central Register of Controlled Trials, and Web of Science from database inception to March 29, 2021. Inclusion criteria encompassed studies that described peripheral nerve stimulation in patients in terms of clinical outcomes for various pain conditions, physiological mechanism of action, surgical technique, technique of placement, and adverse events. Twenty randomized controlled trials and 33 prospective observational studies were included in the systematic review process. There is Level I evidence supporting the efficacy of PNS for treatment of chronic migraine headaches via occipital nerve stimulation; chronic hemiplegic shoulder pain via stimulation of nerves innervating the trapezius, supraspinatus, and deltoid muscles; failed back surgery syndrome via subcutaneous peripheral field stimulation; and lower extremity neuropathic and lower extremity post-amputation pain. Evidence from current Level I studies combined with newer technologies facilitating less invasive and easier electrode placement make peripheral nerve stimulation an attractive alternative for managing patients with complex pain disorders. Peripheral nerve stimulation should be used judiciously as an adjunct for chronic and acute postoperative pain following adequate patient screening and positive diagnostic nerve block or stimulation trial.

Peripheral Nerve Stimulation for Chronic Pain: A Systematic Review of Effectiveness and Safety

Peripheral nerve stimulation (PNS) was the first application of neuromodulation. Widespread application of PNS was limited by technical concerns. Recent advances now allow the percutaneous placement of leads with ultrasound or fluoroscopic guidance, while the transcutaneous powering of these leads removes the need for leads to cross major joints. This systematic review was written to assess the current status of high-quality evidence supporting the use of PNS for pain conditions treated by interventional pain physicians. The available literature on PNS, limited to conditions treated by interventional pain physicians, was reviewed and the quality assessed. Literature from 1966 to June 2021 was reviewed. The outcome measures were pain relief and functional improvement. One hundred and two studies were identified. Five randomized controlled trials (RCT) and four observational studies, all case series, met the inclusion criteria. One RCT was of high quality and four were of moderate quality; all four case series were of moderate quality. Three of the RCTs and all four case series evaluated peripheral nerve neuropathic pain. Based upon these studies, there is level II evidence supporting the use of PNS to treat refractory peripheral nerve injury. One moderate-quality RCT evaluated tibial nerve stimulation for pelvic pain, providing level III evidence for this indication. One moderate-quality RCT evaluated surgically placed cylindrical leads for cluster headaches, providing level III evidence for this indication. The evidence suggests that approximately two-thirds of patients with peripheral neuropathic pain will have at least 50% sustained pain relief. Adverse events from PNS are generally minor. A major advantage of PNS over spinal cord stimulation is the absence of any risk of central cord injury. The study was limited by the paucity of literature for some indications. No studies dealt with joint-related osteoarthritic pain.

Peripherally Induced Reconditioning of the Central Nervous System: A Proposed Mechanistic Theory for Sustained Relief of Chronic Pain with Percutaneous Peripheral Nerve Stimulation

Peripheral nerve stimulation (PNS) is an effective tool for the treatment of chronic pain, although its efficacy and utilization have previously been significantly limited by technology. In recent years, purpose-built percutaneous PNS devices have been developed to overcome the limitations of conventional permanently implanted neurostimulation devices. Recent clinical evidence suggests clinically significant and sustained reductions in pain can persist well beyond the PNS treatment period, outcomes that have not previously been observed with conventional permanently implanted neurostimulation devices. This narrative review summarizes mechanistic processes that contribute to chronic pain, and the potential mechanisms by which selective large diameter afferent fiber activation may reverse these changes to induce a prolonged reduction in pain. The interplay of these mechanisms, supported by data in chronic pain states that have been effectively treated with percutaneous PNS, will also be discussed in support of a new theory of pain management in neuromodulation: Peripherally Induced Reconditioning of the Central Nervous System (CNS).

The Predictive Value of Transcutaneous Electrical Nerve Stimulation for Patient Selection in Peripheral Nerve Field Stimulation for Chronic Low Back Pain: A Prospective Study

OBJECTIVE

Peripheral nerve field stimulation (PNFS) is an effective alternative treatment for patients with chronic low back pain. Transcutaneous electrical nerve stimulation (TENS) is frequently used in pain therapy. Aim of this prospective study was to examine the predictive value of TENS for later PNFS treatment.

MATERIALS AND METHODS

Between 2014 and 2019, a prospective cohort study of 41 patients with chronic lumbar pain was conducted. Pain intensity (NRS) was assessed before and after TENS use, preoperatively/postoperatively and in the follow-up after three and six months, SF12v2 questionnaires with physical (PCS) and mental component summary (MCS) scores, and Oswestry disability index (ODI) questionnaire at baseline as well as three and six months after PNFS implantation. Implantation of the PNFS-system with two percutaneous leads was performed after four to seven days of positive testing. Statistical analysis was performed using depending t-test, ANOVA, and Spearman correlation.

RESULTS

The cohort consisted of 41 patients (19 females, 22 males) with a median age of 60.5 years (IQR^25-75 52-67). Two patients were lost to follow-up. After positive PNFS testing a pulse generator (IPG) was implanted in 15 patients with positive TENS effect and 15 patients without TENS effect. Leads were explanted in nine patients after negative PNFS trial phase. TENS positive patients showed significant correlation to a positive effect in the PNFS trial phase in NRS reduction (p = 0.042) indicating that TENS responders will also respond to PNFS (94% patients). After three and six months follow-up median NRS and SF12v2 (PCS) improved significantly in both cohorts, SF12v2 (MCS) and ODI only in the TENS positive cohort, respectively.

CONCLUSION

TENS can be predictive for patient selection in PNFS, as TENS positive patients showed significant correlation with a positive PNFS trial period. Therefore, TENS positive patients might be justifiable to be directly implanted with leads and IPG. TENS positive patients further tend to show a better improvement in the follow-up.

Peripheral subcutaneous field stimulation for the treatment of spinal cord injury at-level pain: case report, literature review, and 5-year follow-up

Spinal cord injury (SCI) frequently engenders chronic pain which may be classified as occurring above, at, or below the level of injury. Since patients with SCI may have a complex combination of nociceptive and neuropathic pain, pharmacological interventions often fail. Peripheral subcutaneous field stimulation (PSFS) is a novel neuromodulation surgery for pain in which subcutaneous electrodes designed for spinal cord stimulation are placed subcutaneously in a region of pain. We report the case of a 26-year-old man who was an unrestrained driver in a motor vehicle accident and suffered a complete ASIA A spinal cord injury with paraplegia due to a T4 three-column burst fracture. He underwent successful surgical fixation of the fracture (7/27/12) and developed severe at-level SCI-associated pain which failed all conservative measures. After a successful trial, two octrode leads (Abbott Medical, Plano, TX, USA) were placed for PSFS under general anesthesia and were connected to a right flank rechargeable pulse generator (11/6/13). At 60 months postoperative, the patient continues to use the peripheral field stimulation system on a daily basis and reports near complete relief of his at-level spinal cord injury pain. He noted instantaneous relief of his pain once ideal stimulation programming was achieved and has tolerated complete cessation of all narcotic use. His current programming settings are: Frequency of 50 Hz (Hz), Pulse Width of 350 μs (μsec), Amplitude of 0.00 miliamps (mA), Comf of 7.70 mA, and Perc of 4.50 mA. Chronic pain is a challenging and expensive sequela to manage in SCI patients and newer therapies are needed. Our case suggests that SCI at-level pain may respond durably to PSFS and provides the longest published follow-up on a case of PSFS. Peripheral subcutaneous field stimulation remains an investigational treatment for chronic pain syndrome and larger, long-term follow up studies are needed for the FDA and payers to approve this modality.

The Effect of Peripheral Neuromodulation on Pain From the Sacroiliac Joint: A Retrospective Cohort Study

OBJECTIVE

To report a retrospective review of the longer-term results of peripheral neuromodulation in 12 patients with significant chronic sacroiliac joint pain who had previously failed multiple conservative and interventional pain therapies.

METHODS

To allow for the assessment of meaningful longer-term outcome, implants for all 12 patients had been in place for a minimum of 18 months to a maximum of 36 months prior to the formal review.

RESULTS

Compared to the preimplantation baseline, the longer-term follow-up revealed a significant and sustained reduction in visual analog scale pain scores from 8.7T 1.1 to 1.1T 1.0 (p < 0.001), with a 75% reduction in analgesia requirement, and improvement in pain impact on daily function from 94.1% T 5.9% to 5.8% T 6.0% (p < 0.001).

CONCLUSION

This initial case series has highlighted that SIJ neuromodulation results in the reduction in pain intensity and improved functionality in patients who have already failed conventional medical management and interventional techniques, including RF denervation. These preliminary results merit a prospective randomized trial of peripheral neuromodulation.

A Randomized Controlled Trial of Subcutaneous Nerve Stimulation for Back Pain Due to Failed Back Surgery Syndrome: The SubQStim Study

Objectives

To compare the effectiveness of peripheral nerve stimulation utilizing a subcutaneous lead implant technique—subcutaneous nerve stimulation (SQS) plus optimized medical management (SQS + OMM arm) vs. optimized medical management alone (OMM arm) in patients with back pain due to failed back surgery syndrome.

Patients and Methods

Patients were recruited from 21 centers, in Europe, Israel, and Australia. Eligible patients were randomized (1:1) to SQS + OMM or OMM arms. Those in the SQS arm were implanted with a neurostimulator and up to two subcutaneous percutaneous cylindrical leads in the area of pain. Patients were evaluated pre‐randomization and at one, three, six, and nine months post‐randomization. The primary endpoint was the proportion of subjects with a ≥50% reduction in back pain intensity (“responder”) from baseline to nine months. Secondary outcomes included proportion of responders with a ≥50% reduction in back pain intensity at six months and ≥30% reduction at nine months, and the mean change from baseline in back pain intensity at six and nine months between the two arms.

Results

Due to the slow rate of recruitment, the study was terminated early with 116 subjects randomized. A total of 33.9% (19/56, missing: n = 20 [36%]) of subjects in the SQS + OMM arm and 1.7% (1/60, missing: n = 24 [40%]) in the OMM arm were responders at Month 9 (p < 0.0001). Secondary objectives showed a significant difference in favor of SQS + OMM arm.

Conclusion

The results indicate that the addition of SQS to OMM is more effective than OMM alone in relieving low back pain at up to nine months.

Bilateral Peripheral Nerve Field Stimulation for Intractable Coccygeal Pain: A Case Study Using Dual Lead Intercommunication

Coccygeal pain is a difficult chronic pain problem with mixed response to various treatments. This is a report of a case of coccygeal pain that after failing various conservative and interventional procedures over five years was evaluated with a temporary peripheral sacral fascial lead followed by implantation of bilateral sacral paramedian leads for peripheral nerve field stimulation (PNFS). This resulted in marked pain control and resumption of full activity. The visual analog scale (VAS) pain score improved from eight pre-implant to one after implant and has remained at that level in follow-up. Peripheral nerve field stimulation has been reported for axial chronic back pain, post-laminectomy pain and sacroiliac joint pain either alone or in conjunction with epidural spinal cord stimulation. Both single and parallel leads have been used to provide wider stimulation but differences in location have not been examined. This is the first case report of the use of PNFS for treatment of intractable chronic coccygeal pain. The effectiveness of PNFS was established for this patient by using a prolonged 10-day temporary trial period followed by a 30-day interval without stimulation during which the pain returned to the pre-trial level before proceeding with permanent implantation, it was clear that in this case, PNFS was effective for pain control. Interestingly, the trial and permanent leads were both in the posterior sacral fascia but not in identical positions yet equally effective for pain control. The observation of the effectiveness of different positions may indicate that at least for peripheral field stimulation there may be significant current spread in the fascia. Two and three months after the implant, we examined the effect of different lead settings and the effect of unilateral stimulation compared with bilateral stimulation with and without interlead communication. The patient feedback in this case provides some understanding of the effect of field stimulation with different lead placements. A trial of a deep peripheral fascial lead for sacral and coccygeal field stimulation is a simple option and may be a reasonable approach to consider in the range of treatments for chronic coccygeal pain.

Intraoperative Ultrasound for Peripheral Nerve Applications

Offering real-time, high-resolution images via intraoperative ultrasound is advantageous for a variety of peripheral nerve applications. To highlight the advantages of ultrasound, its extraoperative uses are reviewed. The current intraoperative uses, including nerve localization, real-time evaluation of peripheral nerve tumors, and implantation of leads for peripheral nerve stimulation, are reviewed. Although intraoperative peripheral nerve localization has been performed previously using guide wires and surgical dyes, the authors' approach using ultrasound-guided instrument clamps helps guide surgical dissection to the target nerve, which could lead to more timely operations and shorter incisions.

The Effect of Peripheral Neuromodulation on Pain from the Sacroiliac Joint: A Retrospective Cohort Study

We report here a retrospective review of the longer-term results of peripheral neuromodulation in 12 patients with significant chronic sacroiliac joint pain who had previously failed multiple conservative and interventional pain therapies. To allow for the assessment of meaningful longer-term outcome, implants for all 12 patients had been in place for a minimum of 18 months to a maximum of 36 months prior to the formal review. Compared to the preimplantation baseline, the longer-term follow-up revealed a significant and sustained reduction in visual analog scale pain scores from 8.7 ± 1.1 to 1.1 ± 1.0 (P < 0.001), with a 75% reduction in analgesia requirement, and improvement in pain impact on daily function from 94.1% ± 5.9% to 5.8% ± 6.0% (P < 0.001). These preliminary results merit a prospective randomized trial of peripheral neuromodulation.

Interventional Therapies for Chronic Low Back Pain: A Focused Review (Efficacy and Outcomes)

CONTEXT

Lower back pain is considered to be one of the most common complaints that brings a patient to a pain specialist. Several modalities in interventional pain management are known to be helpful to a patient with chronic low back pain. Proper diagnosis is required for appropriate intervention to provide optimal benefits. From simple trigger point injections for muscular pain to a highly complex intervention such as a spinal cord stimulator are very effective if chosen properly. The aim of this article is to provide the reader with a comprehensive reading for treatment of lower back pain using interventional modalities.

EVIDENCE ACQUISITION

Extensive search for published literature was carried out online using PubMed, Cochrane database and Embase for the material used in this manuscript. This article describes the most common modalities available to an interventional pain physician along with the most relevant current and past references for the treatment of lower back pain. All the graphics and images were prepared by and belong to the author.

RESULTS

This review article describes the most common modalities available to an interventional pain physician along with the most relevant current and past references for the treatment of lower back pain. All the graphics and images belong to the author. Although it is beyond the scope of this review article to include a very detailed description of each procedure along with complete references, a sincere attempt has been made to comprehensively cover this very complex and perplexing topic.

CONCLUSION

Lower back pain is a major healthcare issue and this review article will help educate the pain practitioners about the current evidence based treatment options.

The appropriate use of neurostimulation: stimulation of the intracranial and extracranial space and head for chronic pain. Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The International Neuromodulation Society (INS) has identified a need for evaluation and analysis of the practice of neurostimulation of the brain and extracranial nerves of the head to treat chronic pain.

METHODS

The INS board of directors chose an expert panel, the Neuromodulation Appropriateness Consensus Committee (NACC), to evaluate the peer-reviewed literature, current research, and clinical experience and to give guidance for the appropriate use of these methods. The literature searches involved key word searches in PubMed, EMBASE, and Google Scholar dated 1970-2013, which were graded and evaluated by the authors.

RESULTS

The NACC found that evidence supports extracranial stimulation for facial pain, migraine, and scalp pain but is limited for intracranial neuromodulation. High cervical spinal cord stimulation is an evolving option for facial pain. Intracranial neurostimulation may be an excellent option to treat diseases of the nervous system, such as tremor and Parkinson's disease, and in the future, potentially Alzheimer's disease and traumatic brain injury, but current use of intracranial stimulation for pain should be seen as investigational.

CONCLUSIONS

The NACC concludes that extracranial nerve stimulation should be considered in the algorithmic treatment of migraine and other disorders of the head. We should strive to perfect targets outside the cranium when treating pain, if at all possible.

The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The Neuromodulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society (INS) evaluated evidence regarding the safety and efficacy of neurostimulation to treat chronic pain, chronic critical limb ischemia, and refractory angina and recommended appropriate clinical applications.

METHODS

The NACC used literature reviews, expert opinion, clinical experience, and individual research. Authors consulted the Practice Parameters for the Use of Spinal Cord Stimulation in the Treatment of Neuropathic Pain (2006), systematic reviews (1984 to 2013), and prospective and randomized controlled trials (2005 to 2013) identified through PubMed, EMBASE, and Google Scholar.

RESULTS

Neurostimulation is relatively safe because of its minimally invasive and reversible characteristics. Comparison with medical management is difficult, as patients considered for neurostimulation have failed conservative management. Unlike alternative therapies, neurostimulation is not associated with medication-related side effects and has enduring effect. Device-related complications are not uncommon; however, the incidence is becoming less frequent as technology progresses and surgical skills improve. Randomized controlled studies support the efficacy of spinal cord stimulation in treating failed back surgery syndrome and complex regional pain syndrome. Similar studies of neurostimulation for peripheral neuropathic pain, postamputation pain, postherpetic neuralgia, and other causes of nerve injury are needed. International guidelines recommend spinal cord stimulation to treat refractory angina; other indications, such as congestive heart failure, are being investigated.

CONCLUSIONS

Appropriate neurostimulation is safe and effective in some chronic pain conditions. Technological refinements and clinical evidence will continue to expand its use. The NACC seeks to facilitate the efficacy and safety of neurostimulation.

Spinal cord stimulation for neuropathic pain: current perspectives

Neuropathic pain constitutes a significant portion of chronic pain. Patients with neuropathic pain are usually more heavily burdened than patients with nociceptive pain. They suffer more often from insomnia, anxiety, and depression. Moreover, analgesic medication often has an insufficient effect on neuropathic pain. Spinal cord stimulation constitutes a therapy alternative that, to date, remains underused. In the last 10 to 15 years, it has undergone constant technical advancement. This review gives an overview of the present practice of spinal cord stimulation for chronic neuropathic pain and current developments such as high-frequency stimulation and peripheral nerve field stimulation.

Peripheral neuromodulation: a review

Peripheral nerve stimulation (PNS) is likely the most diverse and rapidly expanding area of neuromodulation. Its expansion has become possible due to both technological and clinical advances in pain medicine. The first implantable systems were surgically placed. However, it is currently commonplace to use percutaneous leads, as this approach has become instrumental in its expansion. The first percutaneous peripheral nerve stimulators were reported in 1999. Cylindrical leads were implanted to stimulate the greater occipital nerve to manage intractable headache. It has been expanded into other individual nerves or nerve plexuses to treat neuropathic, visceral, cardiac, abdominal, low back and facial pain. The use of PNS in modulating organ function in treatment of syndromes such as epilepsy, incontinence and obesity with vagal, tibial and gastric stimulation is under extensive investigation. New technologies that allow easier and safer electrode placement are expected to further expand the uses of PNS. A noninvasive stimulation will open this treatment modality to more clinicians of varying backgrounds.

Peripheral nerve/field stimulation for chronic pain

Peripheral nerve stimulation and peripheral nerve field stimulation involve the delivery of electrical stimulation using implanted electrodes either over a target nerve or over the painful area with the goal of modulating neuropathic pain. The selection of appropriate candidates for this therapy hinges on skillful application of inclusion and exclusion criteria, psychological screening, and an invasive screening trial. Patients with significant improvement in pain severity and pain-related disability during the trial are considered candidates for implantation of a permanent system. As with other implanted devices for neuromodulation, risks of mechanical failures, infection, and neurologic complications exist.

Assessing the effectiveness and cost effectiveness of subcutaneous nerve stimulation in patients with predominant back pain due to failed back surgery syndrome (SubQStim study): study protocol for a multicenter randomized controlled trial

BACKGROUND

Chronic radicular pain can be effectively treated with spinal cord stimulation, but this therapy is not always sufficient for chronic back pain. Subcutaneous nerve stimulation (SQS) refers to the placement of percutaneous leads in the subcutaneous tissue within the area of pain. Case series data show that failed back surgery syndrome (FBSS) patients experience clinically important levels of pain relief following SQS and may also reduce their levels of analgesic therapy and experience functional well-being. However, to date, there is no randomized controlled trial evidence to support the use of SQS in FBSS.

METHODS/DESIGN

The SubQStim study is a multicenter randomized controlled trial comparing SQS plus optimized medical management ('SQS arm') versus optimized medical management alone ('OMM arm') in patients with predominant back pain due to FBSS. Up to 400 patients will be recruited from approximately 33 centers in Europe and Australia and will be randomized 1:1 to the SQS or OMM arms. After 9 months, patients who fail to reach the primary outcome will be allowed to switch treatments. Patients will be evaluated at baseline (prior to randomization) and at 1, 3, 6, 9, 12, 18, 24, and 36 months after randomization. The primary outcome is the proportion of patients at 9 months with a ≥50% reduction in back pain intensity compared to baseline. The secondary outcomes are: back and leg pain intensity score, functional disability, health-related quality of life, patient satisfaction, patient global impression of change, healthcare resource utilization/costs, cost-effectiveness analysis and adverse events. Outcomes arms will be compared between SQS and OMM arms at all evaluation points up to and including 9 months. After the 9-month assessment visit, the main analytic focus will be to compare within patient changes in outcomes relative to baseline.

DISCUSSION

The SubQStim trial began patient recruitment in November 2012. Recruitment is expected to close in late 2014.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01711619.