Neuromodulation: Overview

Abstract
Objectives: The Neuromodulation Society of Australia and New Zealand (NSANZ) developed evidence-based best practice guidelines for spinal cord stimulation (SCS) in chronic pain management. The primary objective was to provide clear guidance to support evidence-informed care across Australia and New Zealand, with a focus on patient selection, procedural techniques, and complication management.

Materials and methods: A systematic literature review was conducted using Medline, EMBASE, Trip Pro, and Google Scholar, covering publications from 2010 to July 2024. A total of 283 studies and relevant clinical guidelines were included on the basis of level 1B evidence or strong expert consensus, consistent with the Grading of Recommendations Assessment, Development, and Evaluation criteria. Clinical questions were developed using the Population, Intervention, Comparison, and Outcome framework, and a Delphi process was used to achieve consensus among NSANZ board members.

Results: The guidelines provide comprehensive recommendations on patient selection, preparation, procedural techniques, postimplantation care, and complication management. Additional guidance is included on training standards, quality improvement processes, and the importance of multidisciplinary collaboration. Key recommendations emphasize optimizing patient selection, enhancing procedural safety, and improving treatment outcomes.

Conclusions: These guidelines offer practical, evidence-informed recommendations for the safe and effective use of SCS in chronic pain management. By promoting consistency, transparency, and collaborative care, they aim to guide clinical decision-making and support the delivery of evidence-informed neuromodulation services across Australia and New Zealand.

Abstract
Background: Managing focal neuropathic pain poses significant challenges. Neuromodulation therapies, particularly dorsal root ganglion stimulation (DRG-S), have shown promise in many cases. However, frequent issues with system durability, necessitating revisions, and the complexity of these revisions due to associated difficulties and the limitations in complex cases with difficult access to the epidural space or foramen have prompted practitioners to seek more durable and long-lasting alternatives. Spinal nerve stimulation through an extraforaminal approach offers a promising solution for patients who have exhausted conventional pain therapies or are unsuitable candidates for DRG-S.

Materials and methods: This is a single-center, retrospective data analysis in 73 patients with neuropathic pain who underwent spinal nerve stimulation (SNS) using our facility's novel extraforaminal approach from January 2019 to December 2024. The collected data included patient-reported outcomes. We also reviewed any adverse events, complications, or procedure-related issues.

Results: Initially, extraforaminal SNS was primarily considered for patients with a history of failed DRG-S. Since 2021, however, this approach has become the primary treatment for focal neuropathic pain at our institution. Of the 73 patients trialed, 75% achieved >50% pain relief, causing permanent implantation in 53 patients. Patient satisfaction remained high, with 38 of 42 patients currently implanted reporting satisfaction in a 2024 follow-up survey. Remarkably, >80% of patients implanted in 2019 and 2020 reported sustained satisfaction five and four years after implantation, respectively. No intraoperative complications or serious adverse events were documented during the trial or after implantation, surgical revisions, or explantation.

Conclusion: The extraforaminal SNS approach has shown safety and durability as a treatment for patients with refractory neuropathic pain. With long-term patient satisfaction and a favorable safety profile, it offers a promising alternative to traditional neuromodulation techniques, particularly in complex cases in which DRG-S may be challenging or contraindicated.

Abstract
Background and aims: Percutaneous electrical nerve field stimulation (PENFS) is a minimally invasive, nonpharmacologic approach to treat children with functional abdominal pain disorders (FAPD). Allodynia refers to pain from a stimulus that does not usually provoke pain. We aimed to characterize auricular allodynia during PENFS and associate it with outcomes.

Materials and methods: We conducted a retrospective cohort study reviewing charts of patients who underwent PENFS for an FAPD. We included demographic data, medical history, and validated questionnaire responses. Allodynia was noted through physician notes of localized ear pain, soreness, or tenderness. Baseline clinical scores and PENFS outcomes were compared in patients with and without allodynia.

Results: Of 219 patients with FAPD (mean age 16.2 ± 2.7 years), 79% were female, and 87% were Caucasian; 28% of patients experienced allodynia with no significant demographic differences. The most common gastrointestinal symptoms were abdominal pain (100%) and nausea (70%), and the most common FAPD diagnoses included irritable bowel syndrome (58%) and functional dyspepsia (54%). Of the 93 total visits with allodynia, 44% of the visits had patients report allodynia once and 34% twice. Common interventions included placing
Conclusion: Allodynia in patients with FAPD who underwent PENFS had worse clinical outcomes. Excitation thresholds of rapidly conducting Aβ fibers in the ear are lower than those of nociceptive slowly conducting Aδ and C fibers. Patients with allodynia may require adjustment of nerve fiber stimulation to improve outcomes.