Percutaneous Neuromodulation of the Brachial Plexus and Sciatic Nerve for the Treatment of Acute Pain Following Surgery: Secondary Outcomes From a Multicenter, Randomized, Controlled Pilot Study

German National Guidelines for Epidural Spinal Cord Stimulation for the Treatment of Chronic Pain

INTRODUCTION

Epidural spinal cord stimulation (SCS) or dorsal root ganglion stimulation (DRG-S) is a neuromodulatory, reversible interventional procedure for patients with pain who cannot be adequately treated with conservative and less invasive means. This review provides the recently updated German recommendations for SCS and DRG-S, followed by a standardized diagnostic and therapeutic procedure.

OBJECTIVE

The purpose of this work is to present the current evidence-based results of SCS, including DRG-S, for various neuropathic and nonneuropathic pain conditions. Moreover, it aims to optimize the treatment of patients with chronic pain for whom neuromodulation can be a component in the treatment concept of multimodal pain therapy.

MATERIALS AND METHODS

A systematic literature search was conducted based on a Cochrane analysis, followed by search strategies in the common data bases (PubMed, Medline, and Embase). The relevant literature was reviewed and discussed within working groups. Finally, evaluation of evidence and identification of recommendations was performed by members of the guideline commission comprising representatives of relevant medical societies in Germany.

RESULTS

The first German guideline on SCS was published in April 2013. Any guideline has only limited validity (eg, in Germany, guidelines are valid for a maximum of five years). Owing to the numerous publications in this field, an update had become mandatory. On the basis of literature from 2013 to 2018, indications were newly identified or reevaluated. In addition, new methods were discussed, and predictors for treatment success were defined as part of the psychologic assessment.

CONCLUSION

Neuromodulation, especially SCS, is based on the systematic study of treatment data. Real-world data are indispensable. Particularly in the current situation, in which fundamental questions about the value of SCS are being publicly discussed, sometimes in nonscientific media, it is essential to publish systematic guidelines, on both a national and international level.

Effects of Ultrasound-Guided Percutaneous Neuromodulation on Shoulder Muscle Strength in CrossFit Athletes: A Pilot Randomized Controlled Trial

BACKGROUND

CrossFit integrates diverse functional movements to optimize overall fitness, with muscle strength training being a core component. Ultrasound-guided percutaneous neuromodulation (US-guided PNM) has emerged as a potential adjunct to enhance muscle strength gains; however, its efficacy in the upper limb in healthy individuals remains unexplored.

OBJECTIVE

This study evaluated the efficacy of two US-guided PNM protocols (three sessions and one session) targeting the axillary and suprascapular nerves in improving shoulder muscle strength in healthy CrossFit athletes.

MATERIALS AND METHODS

A pilot, randomized, controlled, single-blind clinical trial was conducted with 39 healthy CrossFit athletes randomly allocated to one of three groups: control (G1, no intervention), one session of US-guided PNM (G2), or three sessions of US-guided PNM (G3). Shoulder muscle strength was assessed using a hand-held dynamometer to measure external and internal rotation muscle strength at various shoulder positions before each treatment session (days 1, 7, and 14) and one week after the last session (day 21). Moreover, the one-repetition maximum (1RM) shoulder press exercise was evaluated on day 1 and day 21.

RESULTS

No statistically significant differences were observed among groups for any outcome. However, the within-group analysis indicated statistically significant improvements over time in the treated limbs of intervention groups (G2 and G3), whereas no statistically significant changes were observed in the control (G1) or the untreated limbs of G2 and G3. The improvements were more consistent for shoulder strength measured in the neutral position than at 90° abduction.

CONCLUSIONS

Although US-guided PNM did not yield significantly greater improvements than did the control group, both one and three sessions targeting the axillary and suprascapular nerves enhanced rotational shoulder muscle strength in treated limbs and 1RM shoulder press performance. These findings should be interpreted with caution, and further investigation is warranted, particularly in populations with lower baseline strength and in exploring varied application parameters to optimize efficacy.

CLINICAL TRIAL REGISTRATION

The Clinicaltrials.gov registration number for the study is NCT06529770.

Current Strategies in Regional Anesthesia for Shoulder Surgery

As arthroscopic and open shoulder surgery is increasingly performed on an outpatient basis, optimal and prolonged pain control is becoming more important while minimizing associated adverse effects. Traditional analgesic strategies relying on opioid and nonopioid medications provide inadequate pain control and are associated with undesirable adverse effects, such as opioid-related adverse effects (postoperative nausea and vomiting, respiratory depression, sedation), gastric lining irritation, and renal and hepatic adverse effects. Advances in ultrasonography-guided regional anesthesia have made placement of interscalene brachial plexus nerve blocks more reliable and precise and aided development of novel phrenic nerve-sparing peripheral nerve block techniques that decrease the risk of diaphragmatic paresis and dyspnea. Using a brachial plexus block combined with multimodal medications is the preferred method to provide comprehensive analgesia to target multiple pain pathways for additive or synergistic pain control effects in the perioperative period while minimizing opioid medication usage. An understanding of current anesthetic and analgesic strategies can lead to an improved pain management pathway and outcomes in patients undergoing shoulder surgery.

Percutaneous auricular neuromodulation (nerve stimulation) for the treatment of pain following total knee arthroplasty: a randomized, double-masked, sham-controlled pilot study

BACKGROUND

Percutaneous auricular nerve stimulation (neuromodulation) is an analgesic technique involving the percutaneous implantation of multiple leads at various points on/around the ear followed by the delivery of electric current using an external pulse generator. A device is currently available within the USA cleared to treat symptoms from opioid withdrawal, and multiple reports suggest a possible postoperative analgesic effect. The current randomized, controlled pilot study was undertaken to (1) determine the feasibility and optimize the protocol for a subsequent definitive clinical trial and (2) estimate the treatment effect of auricular neuromodulation on postoperative pain and opioid consumption following total knee arthroplasty.

METHODS

Within the recovery room following primary, unilateral, total knee arthroplasty, an auricular neuromodulation device (NSS-2 Bridge, Masimo, Irvine, California, USA) was applied using three percutaneous leads and one ground electrode. Participants were randomized to 5 days of either electrical stimulation or sham stimulation in a double-masked fashion. Participants were discharged with the stimulator in situ and removed the disposable devices at home. The dual primary treatment effect outcome measures were the cumulative opioid use (oral oxycodone) and the mean of the "average" daily pain measured with the Numeric Rating Scale for the first 5 postoperative days.

RESULTS

During the first five postoperative days, oxycodone consumption in participants given active stimulation (n=15) was a median (IQR) of 4 mg (2-12) vs 13 mg (5-23) in patients given sham (n=15) treatment (p=0.039). During this same period, the average pain intensity in patients given active stimulation was a median (IQR) of 2.5 (1.5-3.3) vs 4.0 (3.6-4.8) in those given sham (p=0.014). Awakenings due to pain over all eight postoperative nights in participants given active stimulation was a median (IQR) of 5 (3-8) vs 11 (4-14) in those given sham (p<0.001). No device-related localized cutaneous irritation, systemic side effects, or other adverse events were identified.

CONCLUSIONS

Percutaneous auricular neuromodulation reduced pain scores and opioid requirements during the initial week after total knee arthroplasty. Given the ease of application as well as the lack of systemic side effects and reported complications, a definitive clinical trial appears warranted.

TRIAL REGISTRATION NUMBER

NCT05521516.

A single-center retrospective chart review of percutaneous PNS for treatment of chronic shoulder pain

Objective

The present IRB-approved retrospective chart review describes the use of a 60-day PNS treatment for shoulder pain at a single center in 60 total consecutive patients.

Background

Chronic shoulder pain affects an increasing number of patients per year and is especially prevalent in elderly populations. Percutaneous peripheral nerve stimulation (PNS) treatment targeting the nerves of the shoulder has been shown to reduce pain in prospective clinical studies and in analysis of real-world data.

Methods

Data were extracted from the electronic medical records of patients who had previously undergone percutaneous PNS treatment for chronic shoulder pain. Demographic data and treatment characteristics were summarized alongside treatment outcomes.

Results

Overall, 84 % (49/58) of patients reported substantial (≥50 %) pain relief at the end-of-treatment. The records for 2 patients did not include patient-reported percent pain relief. The average indwelling period for leads (i.e., treatment period) was 57 days. Findings on treatment effectiveness were consistent when the patient population was stratified by cause of pain, duration living with pain, and presence of pain-modifying comorbidities. Stimulation paradigms were identified and categorized by the nerve target and stimulation frequency (e.g., motor stimulation, sensory stimulation, or bimodal stimulation).

Conclusions

These results indicate percutaneous PNS is an effective treatment for patients with various shoulder pain histories, and while all stimulation paradigms were effective at reducing pain, patients who received bimodal PNS reported the greatest pain relief. Key limitations of the study included heterogeneous shoulder pain etiologies among patients and sparse availability of long-term follow-up data. These data support existing real-world and prospective clinical evidence on the efficacy of 60-day PNS treatment at treating chronic pain and provide valuable insights into its use in clinical practice.

Biohacking Nerve Repair: Novel Biomaterials, Local Drug Delivery, Electrical Stimulation, and Allografts to Aid Surgical Repair

The regenerative capacity of the peripheral nervous system is limited, and peripheral nerve injuries often result in incomplete healing and poor outcomes even after repair. Transection injuries that induce a nerve gap necessitate microsurgical intervention; however, even the current gold standard of repair, autologous nerve graft, frequently results in poor functional recovery. Several interventions have been developed to augment the surgical repair of peripheral nerves, and the application of functional biomaterials, local delivery of bioactive substances, electrical stimulation, and allografts are among the most promising approaches to enhance innate healing across a nerve gap. Biocompatible polymers with optimized degradation rates, topographic features, and other functions provided by their composition have been incorporated into novel nerve conduits (NCs). Many of these allow for the delivery of drugs, neurotrophic factors, and whole cells locally to nerve repair sites, mitigating adverse effects that limit their systemic use. The electrical stimulation of repaired nerves in the perioperative period has shown benefits to healing and recovery in human trials, and novel biomaterials to enhance these effects show promise in preclinical models. The use of acellular nerve allografts (ANAs) circumvents the morbidity of donor nerve harvest necessitated by the use of autografts, and improvements in tissue-processing techniques may allow for more readily available and cost-effective options. Each of these interventions aid in neural regeneration after repair when applied independently, and their differing forms, benefits, and methods of application present ample opportunity for synergistic effects when applied in combination.

Peripheral Nerve Stimulation in Postoperative Analgesia: A Narrative Review

PURPOSE OF REVIEW

Recent research has shown the effectiveness of peripheral nerve stimulators (PNS) in managing chronic pain conditions. Ongoing studies aim to explore its potential application in treating acute postoperative pain states. The purpose of this systematic review is to assess the role of PNS in providing relief for postoperative pain.

RECENT FINDINGS

Clinical studies investigating the use of peripheral nerve stimulators (PNS) for analgesia following various surgeries, such as total knee arthroplasty, anterior cruciate ligament repair, ankle arthroplasty, rotator cuff repair, hallux valgus correction, and extremity amputation, have shown promising results. Lead placement locations include the brachial plexus, sciatic, femoral, tibial, genicular, perineal, sural, radial, median, and ulnar nerves. These studies consistently report clinically significant reductions in pain scores, and some even indicate a decrease in opioid consumption following PNS for postoperative pain. PNS involves the subcutaneous placement of electrode leads to target peripheral nerve(s) followed by delivery of an electric current via an external pulse generator. While the precise mechanism is not fully understood, the theory posits that PNS modulates electrical stimulation, hindering the signaling of nociceptive pain. PNS presents itself as an alternative to opioid therapy, holding promise to address the opioid epidemic by offering a nonpharmacologic approach for both acute and chronic pain states.

A Case Report of Three Patients Who Underwent Temporary Peripheral Nerve Stimulation for Treatment of Knee Pain Secondary to Osteoarthritis

Knee osteoarthritis affects millions of people worldwide. There remains a role for novel therapies to manage pain for patients who are unable or unwilling to undergo knee arthroplasty. A peripheral nerve stimulator (PNS) may be beneficial in this population. We present a case report of three patients who received temporary femoral or saphenous PNS and were either unwilling or unable to undergo knee arthroplasty. Two of the three patients reported significantly reduced pain and improved functioning. Our case report demonstrates that temporary PNS may offer a safe and effective treatment for chronic knee pain secondary to knee osteoarthritis.

Composing On-Program Triggers and On-Demand Stimuli into Biosensor Drug Carriers in Drug Delivery Systems for Programmable Arthritis Therapy

Medication in arthritis therapies is complex because the inflammatory progression of rheumatoid arthritis (RA) and osteoarthritis (OA) is intertwined and influenced by one another. To address this problem, drug delivery systems (DDS) are composed of four independent exogenous triggers and four dependent endogenous stimuli that are controlled on program and induced on demand, respectively. However, the relationships between the mechanisms of endogenous stimuli and exogenous triggers with pathological alterations remain unclear, which results in a major obstacle in terms of clinical translation. Thus, the rationale for designing a guidance system for these mechanisms via their key irritant biosensors is in high demand. Many approaches have been applied, although successful clinical translations are still rare. Through this review, the status quo in historical development is highlighted in order to discuss the unsolved clinical difficulties such as infiltration, efficacy, drug clearance, and target localisation. Herein, we summarise and discuss the rational compositions of exogenous triggers and endogenous stimuli for programmable therapy. This advanced active pharmaceutical ingredient (API) implanted dose allows for several releases by remote controls for endogenous stimuli during lesion infections. This solves the multiple implantation and local toxic accumulation problems by using these flexible desired releases at the specified sites for arthritis therapies.