Efficacy of a Novel Ultrasound-Guided C8 Dorsal Root Ganglion Puncture Approach and Radiofrequency Treatment for Postherpetic Neuralgia

Abstract

Purpose

While pulsed radiofrequency ablation of spinal nerve roots, particularly targeting the dorsal root ganglion (DRG), has been established for postherpetic neuralgia (PHN), the C8 DRG remains underrepresented in clinical literature due to its unique anatomical constraints. Limited studies address the technical feasibility and efficacy of C8 DRG intervention in both domestic and international practice. This study introduces a novel puncture approach of ultrasound-guided C8 dorsal root ganglion pulsed radiofrequency to evaluate its clinical efficacy and safety of in patients with refractory postherpetic neuralgia.

Patients and Methods

A retrospective analysis was conducted on 17 patients from March 2023 through May 2025 meeting the diagnostic criteria of the Chinese Expert Consensus on the Diagnosis and Management of Postherpetic Neuralgia treated at the Pain Department of Taihe Hospital, Shiyan, Hubei Province were enrolled. All patients underwent the treatment of the puncture approach of ultrasound-guided C8 dorsal root ganglion pulsed radiofrequency. Visual Analog Scale (VAS) scores were recorded and compared preoperatively, at postoperative 48h, and at 1 week, 1 and 3 months postoperatively. The Athens Insomnia Scale (AIS) was used to evaluate changes in sleep quality, and the Generalized Anxiety Disorder 7-item scale (GAD-7) was employed to assess emotional status.

Results

All patients underwent the procedure successfully with no severe complications. At 3-month follow-up, median scores showed significant reductions across all outcome measures (Friedman test, all p<0.001): VAS was 7.0 (IQR 7.0–8.0) to 1.0 (IQR 1.0–1.0) (χ²=65.43, df = 4), AIS was 8.0 (IQR 7.0–12.0) to 2.0 (IQR 2.0–3.0) (χ²=38.72, df = 4), and GAD-7 was 7.0 (IQR 6.0–10.0) to 2.0 (IQR 2.0–3.0) (χ²=54.74, df = 4). These results indicate that the procedure may offer meaningful clinical benefits, particularly in pain relief, insomnia improvement, and anxiety reduction in these patients.

Limitations

Retrospective study, comparator group absence, and patients who underwent radiofrequency treatment were concurrently taking neuropathic pain medications, injected the corticosteroid during the procedure, so subsequent score improvements cannot be definitively attributed to pulsed radiofrequency therapy alone.

Conclusion

This retrospective study preliminarily suggests that ultrasound-guided C8 dorsal root ganglion pulsed radiofrequency therapy may demonstrate favorable safety and potential efficacy.

Introduction

Varicella-zoster virus (VZV) is a ubiquitous, double-stranded DNA alpha herpesvirus that establishes lifelong latency in sensory-ganglion neurons and causes two main human illnesses: primary varicella (chickenpox) and reactivation as herpes zoster (shingles). The disease stages include-Prodromal (pre-rash): Two to three days before the rash, patients typically have fatigue, headache, low-grade fever, and abnormal skin sensations-itching, burning, or prickling; Acute/active: Painful, dermatomal rash appears at the affected dermatome, often leading to marked quality-of-life impairment; and Chronic: About 20% continue to experience pain after the rash resolves, a condition known as postherpetic neuralgia,¹ which is one of the most frequent complications following herpes zoster infection, characterized by persistent severe pain in previously affected dermatomes after cutaneous healing. This condition significantly impairs activities of daily living and quality of life.² Among contemporary PHN interventions, spinal nerve root radiofrequency ablation³ has garnered substantial clinical attention due to its demonstrated efficacy, establishing itself as a mainstream therapeutic approach.

As a percutaneous neuromodulation target, the dorsal root ganglion (DRG), a critical hub for nociceptive transmission, exhibits significant upregulation of voltage-gated sodium channels and inflammatory mediators following peripheral nerve injury. These molecular adaptations prime the DRG for image-guided interventional therapies such as pulsed radiofrequency (PRF), positioning it as a strategic focus for refractory neuropathic pain management.^4,5

Nevertheless, the C8 DRG poses unique technical challenges due to its anatomically complex position,⁶ resulting in limited visualization and interventional access. Consequently, evidence remains scarce in domestic and international literature regarding its clinical application. Recent advances in ultrasound visualization techniques have now enabled reliable targeting of this structure.

Materials and Methods

General Information

This was an uncontrolled, retrospective, single-arm, observational study involving patients who underwent C8 DRG pulsed radiofrequency therapy between March 2023 and May 2025 and was approved by the Medical Ethics Committee of Shiyan Taihe Hospital, Affiliated Hospital of Hubei University of Medicine (Approval No: WZ2025028). 17 patients with postherpetic neuralgia involving isolated C8 dermatomal distribution were enrolled at the Pain Management Department of our institution. All patients were routinely prescribed gabapentin 0.3 g three times daily (TID) orally (PO) upon admission, with gradual tapering initiated at 1 month postoperatively and complete discontinuation achieved by the 3-month follow-up. All participants underwent ultrasound-guided C8 dorsal root ganglion radiofrequency ablation after providing written informed consent. Patients were identified through Taihe hospital HIS Information System using ICD-10 codes B02.2. Electronic health records were screened by two independent investigators to confirm eligibility based on [inclusion/exclusion criteria]. Inclusion criteria included: (1) Age 18 years or older (no upper age limit), (2) Chronic PHN (persistent pain ≥1 month post-rash healing), (3) Strictly unilateral C8 dermatomal involvement with neuropathic pain features, (4) Visual Analog Scale (VAS) score ≥7 despite ≥4 weeks of conventional pharmacotherapy, (5) MRI/CT exclusion of structural pathologies at C8 DRG level, (6) Voluntarily signed informed consent for both intervention and scheduled follow-ups. Exclusion criteria comprised: (1) Younger than 18 years old, (2) Severe cardiac/hepatic/renal insufficiency, (4) Systemic conditions contraindicating percutaneous intervention, (5) Active major psychiatric disorders, (6) Cognitive impairment compromising protocol adherence, (7) Coagulopathy (platelet count <50×10⁹/L or INR >1.5). Discrepancies were resolved by a senior clinician. This study retrieved all consecutive cases diagnosed with PHN (ICD-10: B02.2) meeting C8 dermatome distribution from March 2023 to May 2025 (n=17) through the hospital electronic medical record system. All eligible patients were enrolled consecutively, with no exclusion of qualified participants. No missing data were present in the analyzed variables.

Procedure

Ultrasound-Guided C8 Dorsal Root Ganglion Localization Technique

Segmental identification is achieved via the spatial relationship between cervical transverse processes and nerve roots. Initial nerve localization begins with the C6 nerve root. According to our previous studies,⁷ the C6 nerve root lies between the anterior and posterior tubercles of the C6 transverse process, while the C5 nerve root is situated cranially relative to C6 (Figure 1A). Moving the ultrasound probe caudally reveals the C7 nerve root. Unlike C6, the C7 transverse process possesses only a posterior tubercle (without an anterior counterpart), and the C7 nerve root is positioned adjacent to this tubercle, forming a distinctive “armchair sign” in ultrasound imaging (Figure 1B). At this level, both C5 and C6 contribute to the roots of the brachial plexus. Further caudal probe advancement exposes the C8 nerve root, which lies against the posterior surface of the first rib, resembling a “deck chair” sign on ultrasound. At this juncture: C5 and C6 converge to form the superior trunk of the brachial plexus, C7 forms the middle trunk, and the deep cervical artery courses medially adjacent to the C8 nerve root (Figure 1C). After readjusting the ultrasound probe cephalad once more at the C7-T1 level, where it emerges through the intervertebral foramen with its dorsal root ganglion situated in the dorsoventral aspect of the foramen. At this point, ultrasound imaging reveals a discontinuous bony surface on the dorsal aspect of the first rib, with the deep cervical artery now positioned superolaterally to the C8 dorsal root ganglion (Figure 1D). All procedures were performed using Color Doppler ultrasound system (Mindray Resona R90, China) and Radiofrequency ablation generator (Cosman RFG-1A, USA).

Figure 1.

(A) Ultrasonographic appearance of the C6 nerve root. (B) Ultrasonographic appearance of the C7 nerve root. (C) Ultrasonographic appearance of the C8 nerve root. (D) Ultrasonographic appearance of the C8 DRG. *Target for needle placement. The yellow shaded area represents the upper trunk and middle trunk of the brachial plexus. The white arrow indicates the deep cervical artery. The white line bar indicates the needle puncture path.

Abbreviations: SCM, Sternocleidomastoid muscle; ASM, Anterior scalene muscle; VA, Vertebral artery; DCA, Deep cervical artery; Frist Rib, posterior portion of the first rib; C5, C5 nerve root; C6, C6 nerve root; C7, C7 nerve root; C8, C8 nerve root; C8 DRG, C8 dorsal root ganglion; MT, Middle Trunk of Brachial Plexus; ST, Superior Trunk of Brachial Plexus; AT, Anterior Tubercle; PT, Posterior Tubercle.

Ultrasound-Guided Pulsed Radiofrequency of the C8 Dorsal Root Ganglion: Surgical Technique

The patient is placed in the lateral decubitus position with a pillow placed under the neck to maintain alignment and the shoulder depressed to widen the cervico-thoracic angle (Figure 2A). After standard disinfection and draping, the ultrasound transducer is positioned in the short axis at the C7-T1 level (Figure 2B) to clearly visualize the C8 nerve root. Next, the medial edge of the transducer is tilted cephalad until a concavity appears at the medial aspect of the continuous bony surface (Figure 2C). The target site corresponds to the C8 nerve root descending into this concavity (Figure 1D). Local anesthesia is administered (2% lidocaine hydrochloride 2.5 mL + 0.9% sodium chloride injection 2.5 mL) for subcutaneous infiltration only, ensuring minimal interference with subsequent electrical stimulation testing. A radiofrequency cannula (16 G, 10 cm length, 2 mm active tip) is inserted approximately 5 cm lateral to the transducer, directing the needle toward the C8 nerve root positioned inferiorly in the ultrasound field (Figure 1D) while maintaining visualization of the deep cervical artery and vertebral artery.

Figure 2.

(A) The patient is in the lateral decubitus position; The black square indicates the ultrasound probe placement. M marks the mastoid process, the white arrow points to the palpable cervical articular pillar, and the black arrow indicates the C7 transverse process. (B) The yellow-shaded area indicates the transducer placement at the C7-T1 level, corresponding to Figure 1C. (C) The yellow-shaded area indicates the transducer placement, and the yellow arrow indicates the direction of ultrasound probe movement, corresponding to Figure 1D.

Abbreviations: DCA, Deep cervical artery; VV, Vena vertebralis; AV, Arteria vertebralis; Frist Rib, posterior portion of the first rib; C8, C8 nerve root; C4, C4 vertebral body; C5, C5vertebral body; C6, C6 vertebral body; C7, C7 vertebral body; T1, T1 vertebral body; C8 DRG, C8 dorsal root ganglion.

Following local anesthesia, the RF cannula was advanced to contact the rib’s depressed surface. Electrodiagnostic confirmation was performed using: Sensory stimulation (200 Hz, 0.1Ms), which can elicit pins-and-needles or burning sensations in the patient’s little finger and the ulnar lower third of the forearm, then Motor stimulation: (2 Hz, 1Ms), which can elicit flexion of the patient’s little and ring fingers along with thumb abduction. Reproducing C8 dermatomal paresthesia and myotomal contractions at 0.3–0.6V, these thresholds confirmed proper needle placement adjacent to the C8 dorsal root ganglion. Pulsed radiofrequency modulation was then delivered for 10 minutes using Waveform (3 Hz pulsed frequency and 30 Ms Voltage protocol Pulse width) Initiated at 40V, incrementally increased to patient tolerance (70–90V maximum). Post-procedure, 5 mL of anti-inflammatory analgesic solution containing methylprednisolone 40 mg (Pfizer Pharmaceuticals LLC, Dalian) was injected after negative serial aspiration for blood/CSF. The puncture site was dressed in sterile gauze, followed by ice-pack application to promote hemostasis.

Data Collection

The data reviewed and analyzed included mean age, sex distribution, BMI, disease duration, comorbidities, and medication use. Treatment efficacy was evaluated using the Visual Analog Scale (VAS, 0–10) pre- and postoperatively, A 10-cm straight line was used, and the 2 ends were marked with “no pain” (0) and “severe pain” (10). The distance from the starting point to the mark was the pain intensity score. The Athens Insomnia Scale (AIS) was used to evaluate the effect of pain on patients’ sleep. The total score was 24 points, with more than 6 points indicating insomnia, 4–6 points indicating suspected insomnia, and <4 points indicating no sleep disorder. Generalized Anxiety Disorder 7 items (GAD-7) were used to evaluate the degree of anxiety and depression of patients. GAD-7 score was defined as normal (0–4), anxiety tendency (5–6), mild anxiety (7–10), moderate anxiety (11–17), and severe anxiety (18–21). Operative time was recorded from needle insertion to procedure completion, and follow-up assessments were conducted at postoperative second day, 1 week, 1 month and 3 months.

Statistical Analysis

Data preprocessing and descriptive statistics were conducted with GraphPad Prism software (version 10, GraphPad Inc., San Diego, CA). Continuous variables were summarized as mean ± standard deviation (SD) when normally distributed or median with interquartile range (IQR) for non-normally distributed data. Categorical variables were reported as frequencies and percentages. Data normality was evaluated using the Shapiro–Wilk normality test. Between-group comparisons of continuous variables were performed using, Independent Student’s t-test for normally distributed parameters, Mann–Whitney U-test for non-parametric data, Within-group longitudinal comparisons employed, Repeated-measures ANOVA for normally distributed variables, Friedman test for non-parametric equivalent, significant results were followed by pairwise Wilcoxon signed-rank tests with Bonferroni correction for non-parametric data and Bonferroni-adjusted paired t-tests for normally distributed parameters. Additionally, Linear Mixed Models (LMM) with random intercepts for subjects were fitted to account for repeated measurements and potential covariates, which were fitted in IBM SPSS Statistics 27. For categorical outcomes, differences were assessed using Pearson’s chi-square test or Fisher’s exact test, as appropriate. All statistical tests were two-sided, with P-values <0.05 considered statistically significant.

Result

All 17 patients successfully underwent ultrasound-guided pulsed radiofrequency therapy of the C8 dorsal root ganglion without any severe complications. Table 1 presents the baseline characteristics of the 17 patients, including mean age, gender distribution, body mass index (BMI), disease duration, comorbidities, and medication history.

Table 1.

Demographic and Clinical Characteristics of Patient

Characteristics	Patients
Mean age (years)	61.5±12.6
Male (n)	7 (41.2)
Female (n)	10 (58.8)
BMI (kg/m2)	22.4±1.1
Mean Disease duration (day)	49.9±17.6
Affected side
Left	8 (47.1)
Right	9 (52.9)
Comorbidities
Diabetes	3 (17.6)
Hypertension	5 (29.4)
CAD post-PCI	1 (5.9)
None	8 (47.1)
Opioid analgesics	3 (17.6)

Primary Outcome

The median (IQR) VAS scores decreased from 7.0 (7.0–8.0) at baseline to 4.0 (3.0–5.0) on post-treatment day 2, 3.0 (2.0–3.0) at 1 week, 2.0 (1.0–2.0) at 1 month, and 1.0 (1.0–1.0) at 3 months. The Friedman test indicated significant differences across time points (χ² = 65.43, df = 4, p < 0.001). Post hoc Wilcoxon signed-rank tests with Bonferroni correction confirmed sustained reductions at all intervals, with the most pronounced improvement at 3 months versus baseline (adjusted p < 0.001, large effect size: r = 0.87). Linear mixed model (LMM) analysis further supported a robust time effect (p < 0.001; 95% CI: −6.42 to −5.46), underscoring clinically meaningful pain relief. (Table 2)

Table 2.

Patient Parameter Data at Different Time Points

	Pre-Treatment	Post-Treatment Second Day	Post-Treatment 1 Week	Post-Treatment 1 Month	Post-Treatment 3 Month
VAS (IQR)	7 (7–8)	4 (3–5)	3 (2–3)	2 (1–2)	1 (1–1)
VS pre-treatment (adjusted p)	–	p<0.001	p<0.001	p<0.001	p<0.001
Effect Size (r)	–	0.87	0.87	0.87	0.87
LMM Mean Difference (95% CI)	Reference	−3.1 (−3.6, −2.6)	4.3 (−4.8, −3.8)	−5.4 (−5.8, −4.9)	−5.9 (−6.42, −5.46)
AIS (IQR)	8 (7–12)	7 (5.5–8)	4 (3.5–5)	3 (2–4)	2 (2–3)
VS pre-treatment (adjusted p)	–	p= 0.06	p<0.001	p<0.001	p<0.001
Effect Size (r)	–	0.47	0.71	0.81	0.86
LMM Mean Difference (95% CI)	Reference	−0.5 (−0.8, −0.3)	−1.2 (−1.5, −0.9)	−1.7 (−2.0, −1.3)	−1.8 (−2.2, −1.5)
GAD-7 (IQR)	7 (6–10)	5 (4–6)	4 (4–5)	3 (2–4)	2 (2–3)
VS pre-treatment (adjusted p)	–	p= 0.003	p= 0.001	p<0.001	p<0.001
Effect Size (r)	–	0.74	0.87	0.94	0.97
LMM Mean Difference (95% CI)	Reference	−2.4 (−3.9, −3.6)	−3.8 (−6.2, −5.0)	−5.0 (−8.4, −6.1)	−5.3 (−9.1, −6.5)

Abbreviations: VAS, visual analog scale; AIS, Athens insomnia scale; GAD-7, generalized anxiety disorder 7 items; IQR, Interquartile Range; LMM, Linear Mixed Model.

Secondary Outcomes

As secondary endpoints, AIS and GAD-7 measurements could potentially demonstrate confounding by variations in pain intensity. AIS scores showed progressive reductions over time, decreasing from a median of 8.0 (IQR: 7.0–12.0) at baseline to 2.0 (2.0–3.0) at 3 months (Table 2). While statistical significance was not reached at post-treatment day 2 (p = 0.06), clinically meaningful improvements were observed from 1 week onward, with a large effect size at 3 months (r = 0.86). Clinically meaningful improvements in anxiety symptoms were observed over time. Median scores decreased from 7.0 (IQR: 6.0–10.0) (moderate anxiety) at baseline to 2.0 (2.0–3.0) (minimal anxiety) at 3 months (Table 2), with sustained reductions at all follow-ups (all p < 0.01 vs baseline, large effect size at 3 months: r = 0.97).

By 3 months, most patients achieved clinically significant responses, subclinical insomnia, and minimal anxiety levels, suggesting the intervention’s multimodal therapeutic potential. However, future large-scale randomized controlled trials are needed to further validate its safety and efficacy.

Discussion

Postherpetic Neuralgia (PHN) is defined as a chronic pain syndrome that persists for more than one month after the acute phase of herpes zoster (HZ) has healed. It is one of the most common and debilitating complications of HZ.² Recent clinical studies, both domestic and international, have demonstrated the significant efficacy of spinal nerve root radiofrequency ablation in the treatment of PHN,^3,8,9 providing patients with a novel pain management option. However, due to the unique and deep-seated anatomical location of the C8 dorsal root ganglion (DRG),⁶ research on radiofrequency ablation targeting this region remains scarce in the literature, leaving a notable gap in both clinical practice and scientific exploration. In this study, we preliminarily employ ultrasound-guided pulsed radiofrequency (PRF) of the C8 DRG for the treatment of PHN.

The DRG serves as a crucial target for neuromodulation therapy.^10,11 Anatomically, DRG location exhibits significant regional variations, primarily categorized into three positional types: intraspinal canal, intraforaminal, and extraforaminal. Studies have shown that approximately half of the DRG at C6 and C7 levels are located extraforaminally, whereas thoracic and lumbar DRG are predominantly situated within the intervertebral foramina^12–14 In the sacral region, DRG positioning shifts more centrally: S1 and S2 DRG reside inside the intervertebral foramina, while S3 and S4 DRGs are positioned within the spinal canal. However, the C8 and T1 DRG present unique anatomical challenges due to their proximity to the first rib and supraclavicular fossa (Figure 2B and C), where they are closely associated with critical vascular structures such as the deep cervical artery and vertebral veins/arteries. These anatomical constraints make visualization and intervention exceptionally difficult, posing significant obstacles for therapeutic development and rendering this region a key focus in clinical research. Ultrasound-guided techniques, however, offer a practical solution due to their real-time imaging capabilities, precision in delineating adjacent neural structures, and lack of ionizing radiation.¹⁵ These advantages enable accurate targeting of the C8 DRG, facilitating safer and more feasible interventions in this anatomically complex area.

The regional predilection of herpes zoster follows predictable patterns epidemiologically, with thoracic segment involvement predominating, followed successively by lumbar, cervical, sacral and brachial distribution.¹⁶ Notably, brachial plexus zoster particularly affecting the C8 dermatomal distributions constitutes the rarest presentation clinically. Given that peripheral nerve fibers arising from the brachial plexus mediate upper extremity sensation, current interventional strategies predominantly target focuses on lesioning the symptomatic neural components of the plexus. The brachial plexus exhibits segmentally divergent neural trajectories: while the C5-C7 nerve roots exit the intervertebral foramina in outward and downward directions (with C5 demonstrating greater obliquity than C6/C7), the C8 and T1 roots converge to form the inferior trunk immediately after exiting, adopting a near-horizontal or slightly ascending course. Notably, the C8 root’s deep anatomical position—constrained by the supraclavicular fossa—combined with the dorsal-lateral displacement of the C8 DRG within the intervertebral foramen, creates significant technical challenges for visualization and intervention. Contemporary studies^17,18 have established DRG-targeted radiofrequency ablation as superior in durability and stability of pain relief compared to peripheral nerve approaches.

Pulsed radiofrequency is widely used in the treatment of zoster-associated pain (ZAP) due to its nondestructive nature, which mainly include PRF and radiofrequency thermocoagulation (RF-TC). Different radiofrequency parameters and modes can influence ZAP.¹⁹ Comparative studies suggest that PRF demonstrates more reliable efficacy with fewer complications,^20,21 Building upon this evidence, our study pioneers the application of C8 DRG PRF for postherpetic neuralgia, aiming to achieve optimized clinical outcomes.

This study preliminarily explores ultrasound-guided pulsed radiofrequency modulation of the C8 DRG as a therapeutic intervention for patients with PHN presenting with herpetic lesions localized within the C8 dermatomal distribution. High-voltage long-duration PRF of the DRG has been shown to provide superior analgesia in PHN) as demonstrated in previous studies.¹¹ Based on this evidence, we adopted this PRF protocol for PHN treatment. Given methylprednisolone’s potent anti-inflammatory properties and its ability to mitigate neuropathic pain via suppression of central and peripheral sensitization,²² along with its documented efficacy in reducing DRG inflammation-induced mechanical hypersensitivity,²³ we supplemented PRF therapy with a 5 mL injection of methylprednisolone (40 mg in anti-inflammatory analgesic solution) post-procedure to enhance therapeutic synergy. The VAS scores demonstrated a significant and progressive reduction following treatment. The median (IQR) scores decreased from 7.0 (7.0–8.0) at baseline to 4.0 (3.0–5.0) by day 2 post-treatment, further declining to 3.0 (2.0–3.0) at 1 week, 2.0 (1.0–2.0) at 1 month, and 1.0 (1.0–1.0) at 3 months (Table 2). The Friedman test confirmed significant differences across all time points (χ² = 65.43, df = 4, p < 0.001), indicating sustained pain relief over time. Three patients required opioid analgesics (Tramadol) orally prior to surgery due to intolerable pain, and after treatment, their VAS scores showed significant improvement. Median AIS scores progressively declined over time, falling from 8.0 (IQR 7.0–12.0) at baseline to 2.0 (2.0–3.0) by 3 months (Table 2). Although the reduction at day 2 post-treatment did not reach statistical significance (p = 0.06), Anxiety symptoms demonstrated statistically and clinically significant improvements longitudinally. Median scores declined from 7.0 (moderate anxiety; IQR 6.0–10.0) at baseline to 2.0 (minimal anxiety; 2.0–3.0) by 3 months (Table 2), with all follow-ups showing sustained reductions (all p < 0.01 vs baseline; large effect size at 3 months: r = 0.97). Notably, the observed improvements in sleep and affective domains align with the multidimensional therapeutic goals for PHN, warranting further investigation into this intervention’s role in holistic management.

This study has several limitations, including its single-center design, small sample size, and relatively short postoperative follow-up. These factors may limit the generalizability of the findings and preclude conclusions regarding therapeutic efficacy. The lack of a control group prevents definitive conclusions about treatment efficacy versus natural history. While corticosteroid co-administration and neuropathic pain medication (Gabapentin) was standardized, its anti-inflammatory effects may synergize with our intervention, so subsequent score improvements cannot be definitively attributed to pulsed radiofrequency therapy alone, randomized controlled pharmacologic studies are required in future. Patients were recruited from a tertiary center, potentially selecting for more severe/recalcitrant cases. Generalizability to community-based PHN populations requires validation, and retrospective data collection risks documentation inaccuracies, prospective registries would improve reliability.

In summary, ultrasound-guided pulsed radiofrequency therapy targeting the C8 DRG shows promising feasibility, clinically meaningful efficacy, and reasonable procedural efficiency for managing PHN. Given its technical advantages, this approach may help address an important unmet need in PHN management and could be considered for broader clinical adoption following further validation.

Funding Statement

This study was supported by the Hubei Provincial Clinical Research Center of Central Nervous System Repair and Functional Reconstruction, Taihe Hospital. (2025SJZX027).

Ethics Approval

This study was conducted in accordance with the Declaration of Helsinki.

Disclosure

The authors report no conflicts of interest in this work.