Fast-acting subperception therapy in spinal cord stimulation (FAST-SCS) uses low-frequency, subthreshold stimulation to engage the dorsal column-mediated surround inhibition mechanism and thereby relieve pain. Our study was performed to better characterize the multidimensional long-term clinical outcomes of FAST-SCS therapy in patients with chronic low back and/or leg pain. Our prospective, multicenter, single-arm, open-label trial, conducted at 12 pain management centers across the USA, included male and female patients with chronic low back pain with/without leg pain refractory to conservative therapy. All eligible patients received an SCS implant. Outcomes evaluated included pain relief, disability, mobility, health-related quality of life, sleep quality, depression, pain catastrophizing, and global impression of change. Fifty-six patients received a permanent SCS implant and 55 were activated with FAST-SCS therapy. At 12months, 89% and 59% of patients achieved ≥ 50% and ≥ 80% pain relief, respectively (p < 0.0001), and pain intensity (verbal numerical rating scale) decreased by 4.9 ± 2.2 points (p < 0.0001). Significant improvements were observed in disability (Oswestry Disability Index - 24 ± 16 points, p < 0.0001) and endurance (6-Minute Walk Test + 73 ± 96m, p < 0.0001), while mobility and balance improved without reaching statistical significance (Timed Up-and-Go test - 7.5 ± 37.5s, p = 0.17). All psychosocial measures improved significantly at 12months compared to baseline, with an increase in the EQ5D-5L index (+ 0.200 ± 0.182, p < 0.0001) and decreases in the Pittsburgh Sleep Quality index (- 3.96 ± 4.31, p < 0.0001), Pain Catastrophizing Score (- 13.3 ± 11.4, p < 0.0001), and Beck Depression Index (- 7.9 ± 10.0, p < 0.0001). At 12months, 87% of patients reported being "much" or "very much" improved. Responses to FAST-SCS were at or above the minimal clinically important differences across all measured clinical dimensions. This prospective study demonstrated that FAST-SCS provided statistically significant, multidimensional benefits across pain, disability, mobility, and psychosocial outcomes over 12months in patients with chronic low back and/or leg pain. These findings support the use of FAST-SCS in this patient population. ClinicalTrials.gov (NCT04618471). https://www. gov/study/NCT04618471 .

Postherpetic neuralgia (PHN) is the most common complication of herpes zoster (HZ), characterized by persistent neuropathic pain that significantly impairs quality of life. Despite the availability of multiple treatment options, PHN remains under-recognized and undertreated, with wide variation in management practices across Europe. This Delphi consensus aimed to: (1) identify key challenges and unmet needs in PHN diagnosis and management; (2) determine the optimal use and positioning of topical treatments, such as lidocaine-medicated plasters; and (3) develop best-practice recommendations to support clinical decision-making and improve patient outcomes. A modified Delphi methodology was followed. An international steering group (SG) comprising seven healthcare professionals (HCPs) experienced in PHN management met online and developed 42 consensus statements for inclusion in an HCP survey; 16 statements were adapted for inclusion in a patient survey. Each statement was presented with a four-point Likert scale to assess agreement, and the surveys were distributed online by a third party to 640 HCPs and 205 patients located in France, Germany, Ireland, Italy, and the UK. Consensus was defined a priori as ≥ 75% agreement. The SG reviewed the results at a second meeting, identified key findings, and formulated best-practice recommendations. A total of 205 HCPs experienced in managing PHN and 26 patients with PHN completed the surveys. Consensus was achieved on 41 of 42 statements in the HCP survey and on all 16 statements in the patient survey. The SG reviewed and discussed the consensus results and formulated eight key recommendations addressing HZ prevention, PHN diagnosis, and optimization of management, including the appropriate positioning of topical therapies and multidisciplinary care. The results of this consensus highlight the unmet needs in PHN care. Implementation of the recommendations into clinical practice is hoped to support more consistent, patient-centered management and improved outcomes for individuals with PHN across Europe.

Acute postoperative pain remains prevalent among patients undergoing gastrointestinal tumor surgery. The study was conducted to evaluate the efficacy of transcutaneous auricular vagus nerve stimulation (taVNS) in alleviating postoperative pain in this population. This patient- and assessor-blinded randomized controlled trial was conducted at the Second Affiliated Hospital of Zhejiang University School of Medicine. Eligible participants who underwent elective laparoscopic gastrointestinal tumor surgery were randomly assigned to the taVNS or control stimulation group. Both groups received the stimulation on the day before surgery and the day after surgery. The primary outcome was the change in visual analogue scale (VAS) scores at 24h postoperatively. The median reduction in VAS scores was 12.0 in the taVNS group, compared with 5.0 in the control stimulation group (median [interquartile range, IQR] 12.0 [10.0-13.3] mm vs 5.0 [2.0-8.0] mm; P < 0.001). Additionally, the taVNS group showed lower cumulative morphine milligram equivalents (MME) at 48h (median [IQR] 0 [0-5] mg vs 5 [0-10] mg; P=0.004) and 72h (median [IQR] 0 [0-5] mg vs 5 [0-10] mg; P=0.002), and shorter time to first flatus (median [IQR] 45 [40-60]h vs 75 [60-85]h; P < 0.001). The incidence of complications, length of hospital stay, and quality of recovery-15 (QoR-15) scores are similar between groups. TaVNS statistically alleviated postoperative pain in patients undergoing gastrointestinal tumor surgery, decreased analgesic requirements, and promoted gastrointestinal function recovery. NCT06763913.

Insulin resistance (IR) is an important factor in the development of chronic pain. The triglyceride-glucose (TyG) index is a convenient measure of insulin resistance. However, as a common subtype of chronic pain, the relationship between postherpetic neuralgia (PHN) and the TyG index remains unclear. Through a retrospective analysis of the relationship between the TyG index and the incidence of PHN, we aim to determine whether the TyG index possesses predictive capability for PHN occurrence, thereby enabling the development of strategies to reduce the incidence of PHN. This retrospective study analyzed the medical records of patients diagnosed with acute herpes zoster (with a disease course of ≤ 1month) in the Pain Department of Jiaxing University Affiliated Hospital from November 2024 to May 2025. Eligible patients were those who had available data on triglycerides and glucose, and no history of diabetes. Relevant clinical data were extracted from existing records and subjected to retrospective analysis. The numerical rating scale (NRS) score was utilized as the primary outcome measure to assess whether patients developed PHN. Those who still had pain (NRS ≥ 4) were classified as the PHN group, while those without pain symptoms (NRS < 4) were classified as the non-PHN group. The association between the TyG index and PHN was evaluated using multi-model logistic regression. In addition, the nonlinear relationship between these indicators and the results was studied using a restricted cubic spline plot. Subsequently, subgroup analyses were conducted on the sensitive population. The predictive value of the TyG index for PHN was evaluated using the receiver operating characteristic curve. The retrospective study comprised 157 patients with acute herpes zoster, of whom 55 were male and 102 female, with a mean age of 64.87 ± 11.67years. The TyG index in patients with acute herpes zoster exhibited a nonlinear relationship with PHN, with an odds ratio (OR) and 95% confidence interval (CI) of 4.32 (1.56-11.97). A linear correlation was found between the triglyceride-glucose-body mass index (TyG-BMI) and PHN, with OR and 95% CI of 1.07 (1.02-1.11). The TyG index and the TyG-BMI showed similar performance on the receiver operating characteristic (ROC) curve for evaluating PHN and have certain predictive value. Higher TyG index and TyG-BMI are associated with an increased risk of PHN. ClinicalTrials.gov identifier, ChiCTR2500113190 (retrospectively registered). Registration Date: November 26, 2025.

The rising global prevalence of obesity has established bariatric surgery as a key therapeutic option; however, postoperative pain management remains a challenge. This study investigated the influence of body mass index (BMI) stratification on acute postoperative pain in patients undergoing bariatric surgery. Fifty-five patients aged 18-65years with BMI ≥ 30kg/m2 scheduled for laparoscopic sleeve gastrectomy were categorized into the obesity group (O group; 30kg/m2 ≤ BMI < 40kg/m2) and the severe obesity group (SO group; BMI ≥ 40kg/m2). Preoperative pain threshold and pain tolerance threshold, perioperative inflammatory cytokines, Brief Pain Inventory (BPI) scores, Quality of Recovery-15 (QoR-15) scores, postoperative resting and movement numeric rating scale (NRS) scores, patient-controlled analgesia (PCA) pump usage, cumulative analgesic consumption, and analgesic satisfaction were assessed. Compared with the O group, the SO group demonstrated a significantly higher pain tolerance threshold (4.1 ± 0.8 vs. 3.5 ± 1.0, P < 0.01), along with lower demand for PCA and reduced consumption of cumulative morphine milligram equivalents and flurbiprofen (P < 0.05). Notably, the primary outcome, the 24-h BPI score, showed no significant difference between the two groups. On postoperative days 1 and 3, tumor necrosis factor-α (TNF-α) levels were significantly lower in the O group, whereas no significant intergroup differences were observed in other inflammatory cytokines. No significant differences were observed in NRS or QoR-15 scores between the two groups. BMI may be considered as a factor for stratifying postoperative analgesia, favoring multimodal, opioid-sparing strategies in patients with severe obesity who demonstrate higher pain tolerance and lower analgesic requirements. Chinese Clinical Trial Registry, ChiCTR2400095080.

Chronic pain is associated with central pain network-associated alterations. Functional MRI (fMRI) provides a powerful, non-invasive imaging technique to visualize such alterations. This feasibility study attempted to investigate the impact of BurstDR spinal cord stimulation (SCS) on fMRI correlates in patients with chronic pain. This proof-of-concept study included 11 patients (8m/3 f; mean age 69.1 ± 11.2years) with chronic back and/or leg pain with BurstDR SCS. Clinical outcomes were assessed at baseline and after 3months BurstDR SCS (Numeric Rating Scale (NRS), Pittsburgh Sleep Quality Index (PSQI), Beck Depression Inventory (BDI), Oswestry Disability Index (ODI)). fMRI (1.5T) was obtained using a classic block-design motor with task and rest with single-subject and group analyses. Pain decreased at follow-up (NRS: 7.3 ± 1.7 vs. 4.4 ± 1.5; p < 0.001) with improved functional capacity (PSQI: 10.2 ± 3.6 vs. 8.1 ± 2.7; p = 0.009; BDI: 16.9 ± 8.2 vs. 11.9 ± 6.3; p = 0.027; ODI: 56.5 ± 18.3 vs. 45.2 ± 16.4; p = 0.001). In the fMRI analyses, ten patients were included. Movement of the left foot led to significant activation in the medial region of the right precentral gyrus (Z > 3.1, p < 0.05). No differences at the predefined threshold for the entire brain were detected, although the uncorrected voxel-wise analysis showed several regions with increased activation post BurstDR SCS (bilateral middle temporal gyri (left: Z = 3.56, uncorrected p < 0.001; right: Z = 4.48, uncorrected p < 0.0001)). Functional connectivity analyses in 9 patients revealed no significant differences in task-modulated functional connectivity. BurstDR SCS reduced pain intensity and improved functional status associated with task-related activation of the motor cortex, which was reproducible across the entire cohort. Further randomized controlled studies are warranted to validate these findings and to elucidate the underlying mechanisms. German Clinical Trials Register (DRKS ID: DRKS00035826).

IntroductionThe sacral erector spinae plane (S-ESP) block is a recently described regional anesthesia technique that targets sacral dermatomes. First reported in 2019, it has been increasingly explored as a potential option for perioperative analgesia in surgeries involving the sacral, perineal, and pelvic regions. This review aims to summarize and critically appraise the current anatomical, technical, and clinical evidence on the S-ESP block, outlining its mechanisms of action, approaches, efficacy, and safety while identifying research gaps and future directions.MethodsWe performed a narrative review integrating anatomical descriptions, sonographic techniques, and available randomized controlled trials (RCTs) evaluating the clinical efficacy of the S-ESP block. A comprehensive literature search was conducted in PubMed, Embase, Scopus, Web of Science, and Ovid (Medline) from inception to July 21, 2025, without language or date restrictions. Full-text RCTs investigating ultrasound-guided S-ESP blocks for perioperative analgesia were reviewed and summarized.ResultsFourteen RCTs (published 2023–2025) were included, conducted predominantly in Turkey, India, and Egypt, spanning pediatric (6 months to 12 years) and adult populations undergoing circumcision, hypospadias repair, hemorrhoidectomy, pilonidal sinus surgery, transurethral resection of prostate, lumbar discectomy, and total hip arthroplasty. Most pediatric trials compared midline S-ESP with caudal or penile blocks, generally demonstrating a longer time to first rescue analgesia and reduced postoperative analgesic consumption, although one study reported a superior duration with caudal block. In adults, the S-ESP block consistently reduced pain scores and opioid requirements.ConclusionsCurrent evidence suggests that both midline and paramedian S-ESP techniques are technically feasible, appear safe in the short term, and provide clinically relevant postoperative analgesia in selected pediatric urogenital, adult anorectal, and orthopedic surgeries. However, heterogeneity in techniques, small single-center samples, and a narrow range of indications limit its generalizability. Large, multicenter RCTs with standardized protocols are needed to clarify the optimal approaches, dosing strategies, and comparative role of S-ESP block versus established neuraxial and peripheral techniques.

Pudendal neuralgia (PN) is a chronic neuropathic pain syndrome affecting the pudendal nerve, often presenting with perineal or pelvic pain exacerbated by sitting. The aim of this systematic review was to summarize the existing knowledge on the diagnosis and management of PN. A PubMed database search identified 475 articles, of which 35 met the inclusion criteria. Nine studies focused on diagnostic strategies, and 26 on management. Diagnosis of PN is largely clinical, with the Nantes criteria providing a widely adopted framework. Imaging modalities such as MRI and MR neurography, along with neurophysiological tests including quantitative sensory testing, have been explored as adjuncts, though their roles remain limited. Pudendal nerve blocks are both diagnostic and therapeutic, with response rates up to 94%. Management follows a stepwise approach, beginning with conservative therapies and progressing to nerve blocks, and extending to neuromodulation or surgery when necessary. Pulsed radiofrequency and nerve stimulation techniques demonstrate promising results, with reported pain reduction in up to 95% of refractory cases, though long-term durability remains uncertain. Surgical decompression remains the most common operative option, with several techniques described. Despite the established recognition of PN, there is a paucity of high-quality comparative studies and randomized controlled trials assessing diagnostic accuracy and treatment efficacy. Current evidence suggests conservative measures and nerve blocks are sufficient for most patients, with stimulation techniques and decompression surgery reserved for refractory cases. Emerging modalities may offer future therapeutic options, but require validation in larger cohorts.

Anatomical variations in nerves are common and can significantly impact ultrasound-guided regional anesthesia. They directly influence needle trajectory, local anesthetic spread, and block efficacy, contributing to procedural failure or complications. However, the literature specifically addressing the clinical implications of neural variations for regional anesthesia remains limited. This narrative review synthesizes evidence on three key aspects: (1) variations of common peripheral nerves and their clinical significance in regional anesthesia (including the terminal branches of the trigeminal nerve, suprascapular nerve, phrenic nerve, lumbar plexus, saphenous nerve, obturator nerve, and sciatic nerve); (2) variations of major vessels relevant to regional anesthesia and their clinical significance in regional anesthesia (including the Adamkiewicz artery and vertebral artery); (3) variations of the spine and spinal nerve roots and their clinical significance in regional anesthesia. This review systematically synthesizes current evidence on these anatomical variations and introduces practical resources, including regional ultrasound guidance and tables correlating specific variants with technical modifications, to enhance ultrasound recognition and clinical decision-making, thereby serving as a valuable reference for clinicians.