Comparison of High-voltage- with Standard-voltage Pulsed Radiofrequency of Gasserian Ganglion in the Treatment of Idiopathic Trigeminal Neuralgia

Pulsed Radiofrequency for Auriculotemporal Neuralgia: A Case Report

Auriculotemporal neuralgia is a rare facial pain disorder with no therapeutic evidence for refractory cases. We described a male patient with right auriculotemporal neuralgia, refractory to anesthetic nerve blocks and botulinum toxin type A injections, who was successfully treated with pulsed radiofrequency without adverse events. Pulsed radiofrequency may be an effective and safe treatment for refractory auriculotemporal neuralgia.

Efficacy and Safety of High-Voltage Pulsed Radiofrequency versus Standard-Voltage Pulsed Radiofrequency for Patients with Neuropathic Pain: A Literature Review and Meta-Analysis

Background

Neuropathic pain (NP) is recognized as one of the most difficult pain syndromes which lacks a safe, well-tolerated and effective treatment. Pulsed radiofrequency (PRF), a novel and minimally invasive interventions, has been introduced to alleviate various types of NP. Previous studies reported PRF with higher voltage could further improve the treatment efficacy. Therefore, we conducted this systematic review and meta-analysis to determine whether high-voltage PRF is superior to standard-voltage PRF for the treatment of NP patients.

Methods

Databases published from the date of inception until 15 March 2022 on PubMed/MEDLINE, EMBASE, Web of Science and the Cochrane Library were searched for RCTs comparing high-voltage PRF and standard-voltage PRF in NP patients. The primary outcome measures were the efficiency rates of NP patients with high-voltage PRF or standard-voltage PRF treatment. Data analysis was conducted using the Review Manager software (RevMan V.5.3).

Results

Six RCTs involving 423 patients were included in our meta-analysis. Compared with standard-voltage PRF group, the high-voltage PRF group attained a higher efficiency rate at 1 month (P = 0.04; I2 = 0%), 3 months (P = 0.04; I2 = 0%), 6 months (P = 0.002; I2 = 0%) post-procedure respectively. There was no significant difference in the complications between the two groups.

Conclusion

Our study supported that high-voltage PRF attained more satisfactory efficacy than standard-voltage PRF without increased side effects. High-voltage PRF could be a promising, effective, minimally invasive technology for NP patients.

High-voltage pulsed radiofrequency improves ultrastructure of DRG and enhances spinal microglial autophagy to ameliorate neuropathic pain induced by SNI

Neuropathic pain (NeP) is intractable for which many therapies are ineffective. High-voltage pulsed radiofrequency (HVPRF) on dorsal root ganglion (DRG) is considered an effective treatment for NeP. The aim of this study is to explore the therapeutic voltage for the optimal efficacy of PRF and the underlying mechanisms. The radiofrequency electrode was placed close to the L5 DRG of rats with spared nerve injury (SNI) and emitted current by the corresponding voltage in different groups. Four different voltages (45 V, 65 V, 85 V, and 100 V) of PRF on DRG significantly alleviated the SNI-induced NeP, reduced the levels of activating transcription factor 3 (ATF3) in DRG, improved the ultrastructure of DRG, and promoted autophagy in spinal microglia to varying degrees and partially reversed the increased expression of TNF-α and the reduced expression of IL-10 in spinal cord dorsal horn (SCDH). The beneficial effect of 85V-PRF was superior to those of other three PRF treatments. The underlying mechanisms may be related to repairing the DRG damage and improving the DRG ultrastructure while regulating spinal microglial autophagy and thereby alleviating neuroinflammation.

Efficacy of High-Voltage Pulsed Radiofrequency of the Dorsal Root Ganglion for Treatment of Chronic Lumbosacral Radicular Pain: A Randomized Clinical Trial

BACKGROUND

Pulsed radiofrequency (PRF) is an efficacious treatment for patients with lumbosacral radicular pain, but the optimal radiofrequency parameters are inadequately described. We hypothesized that high-voltage radiofrequency therapy around the dorsal root ganglion can be more effective and enduring than the standard voltage PRF therapy.

MATERIALS AND METHODS

This was a prospective and randomized study. Patients were divided into two groups. In group 1 (high-voltage group), PRF was applied at 60 V to the patients. Patients in group 2 (low-voltage group) received PRF treatment at 45 V. The patients were evaluated using a numeric rating scale (NRS) and the Oswestry Disability Index (ODI). Evaluation scales were repeated before the intervention and at the first and sixth months after the treatment.

RESULTS

The study included 41 analyzed patients. There was no statistically significant difference between the groups at the first-month NRS (p > 0.05). Sixth-month NRS scores were lower in the high-voltage group (p = 0.016). The groups showed no statistically significant differences in the one-month ODI scores (p > 0.05). When the NRS values were analyzed with linear regression, a positive correlation was found between the sixth-month NRS values and high-voltage PRF (odds ratio: 0.385; p = 0.013). Comparison of the treatment success in terms of time showed statistically significant results in both groups in the first and sixth months (p < 0.05).

CONCLUSIONS

The results of our study revealed that both low- and high-voltage PRF are effective. Because of the lower sixth-month NRS values in the high-voltage group and the similar complication rate, it was considered that high-voltage PRF can be a promising application.

Effectiveness and safety of high-voltage pulsed radiofrequency to treat patients with primary trigeminal neuralgia: a multicenter, randomized, double-blind, controlled study

BACKGROUND

Trigeminal neuralgia (TN) is a debilitating pain disorder that still lacks an ideal treatment option. Pulsed radiofrequency (PRF), especially with high output voltage, is a novel and minimally invasive technique. PRF is regarded a promising treatment option for TN patients who respond poorly to medical treatment; however, the available evidence still lacks high quality randomized controlled trials (RCTs). Our study aimed to evaluate the long-term (1 year and 2 years) effects and safety of high-voltage PRF in primary TN patients and provide stronger evidence for TN treatment options.

METHODS

We performed a multicenter, double-blind, RCT in adults (aged 18-75 years) with primary TN who responded poorly to drug therapy or were unable to tolerate the side effects of drug. Eligible participants were randomly assigned (1:1) to receive either high voltage PRF or nerve block with steroid and local anesthetic drugs. The primary endpoint was the 1-year response rate. This trial has been registered in the clinicaltrials.gov website (registration number: NCT03131466).

RESULTS

One hundred and sixty-two patients were screened for enrollment between April 28th,2017 and September1st, 2019, among whom, 28 were excluded. One hundred and thirty-four participants were randomly assigned to either receive high voltage PRF (n = 67) or nerve block (n = 67). The proportion of patients with a positive response at 1-year after the procedure in the PRF group was significantly higher than that in the nerve block group in the intention-to-treat population (73.1% vs. 32.8%, p < 0.001). There was no difference between groups in the incidence of adverse events.

CONCLUSIONS

Our findings support that high voltage PRF could be a preferred interventional choice prior to receiving more invasive surgical treatment or neuro-destructive treatment for TN patients who have poor responses to medical treatment.

TRIAL REGISTRATION

Our study has been registered at ClinicalTrials.gov (trial registration number: NCT03131466).

How Far Has Radiofrequency Thermocoagulation Come Along as a Treatment Procedure in Treating Trigeminal Neuralgia Patients?

Trigeminal neuralgia (TN) refers to sudden shooting pain in areas innervated by trigeminal nerves originating from the Gasserian ganglion. Physicians initially manage it by prescribing drugs, such as carbamazepine. Surgical intervention is the next best option if patients do not respond to drug treatments. These procedures include microvascular decompression, rhizotomy, balloon compression, and gamma knife surgery. However, less optimal patient outcomes, recurrences, adverse effects, and high costs have necessitated alternative surgical interventions to treat such patients. Radiofrequency thermocoagulation (RFT) has emerged as a minimally invasive, safer, and effective surgical option in treating TN patients. Despite research showing RFT's safety and effectiveness, neurosurgical healthcare providers do not frequently use it to treat TN patients. Lack of universal standardized protocol, and minimal awareness of its efficacy in specific cohorts, such as geriatric patients, may lead to RFT underutilization. Hence, this review highlights RFT's advancement as a robust alternative to traditional surgical approaches in treating TN patients. In addition, it identifies RFT's areas of improvement and its safety and effectiveness in treating elderly TN patients. We followed the Systematic Reviews and Meta-Analyses guidelines for systematic reviews and conducted a literature search between July 2022 and March 2023. Our findings indicate that RFT has evolved significantly over the last decade and a half as a minimally invasive and effective treatment procedure for TN patients. It is more effective as a combined continuous and pulsed RFT than its other subtypes in treating primary TN patients. Moreover, RFT via a transverse puncture through the supraorbital foramen results in lesser inter- and post-procedural complications. Further, there is a slightly lesser incidence of post-procedural adverse effects and complications with RFT through the foramen rotundum. Besides, RFT, performed at a lower temperature of 65 degrees Celsius and a voltage between 64.51 and 79.29 volts, effectively provides pain relief and long-term patient satisfaction. RFT is safe and effective in patients over 60 with primary TN. Interestingly, it is also safe and effective in treating patients over 70 with poor fitness standards of Class II or higher. Despite these remarkable findings, there is still a substantial gap in the literature, specifically concerning the standardized protocol for temperature, voltage, and puncture methods of RFT. Despite the sufficient evidence of combined continuous and pulsed RFT's superiority in efficacy and safety, most researchers still utilize either pulsed or continuous RFT. Studies vary in not only these aspects but also the patient cohorts. For instance, most researchers focus solely on evaluating RFT's efficacy and safety in patients with primary TN, excluding a critical patient population suffering from secondary TN. Nevertheless, sufficient clinical evidence shows that RFT has come of age in treating primary TN patients. However, more extensive studies with large sample sizes of patients with primary and secondary TN with multiple trigeminal nerve affectation will significantly help standardize RFT protocol and its inclusion in the standard clinical practice in treating TN patients.

Comparison of efficacy according to voltage of pulsed radiofrequency treatment to lumbar dorsal root ganglion in patient with lumbar radiculopathy: Pilot study

BACKGROUND

Lumbar radicular pain (LRP) is a common symptom, but a challenging clinical problem. Pulsed radiofrequency (PRF) is a more recently developed technique that uses short pulses of radiofrequency current with intervals of longer pauses to prevent temperature from rising to the level of permanent tissue damage and has been advocated in treatment of such patients. But there were no comparative studies on the analgesic effects according to output voltage during PRF in patients with LRP. The goal of this study is to determine the clinical effect of high-voltage (60V) versus standard-voltage (45V) PRF of lumbar dorsal root ganglion.

METHODS/DESIGN

This study will be a prospective, double-blind randomized controlled pilot study. In this study, total 20 patients will be recruited and distributed equally into 2 groups: high-voltage (60V) PRF, low-voltage (45V) PRF. Outcomes will be radicular pain intensity; physical functioning; global improvement and satisfaction with treatment; and adverse events. The assessments will be performed at the 3-month follow-up period after the end of the treatments. The findings will be analyzed statistically considering a 5% significance level (P ≤ .05).

DISCUSSION

The results of this trial will help determine which voltage could be applied for PRF to dorsal root ganglion in LRP and be a basis for subsequent trials.

Clinical Efficacy of a Spiral CT-Guided Balloon Compression Day-Surgery Operation for the Treatment of Trigeminal Neuralgia

Objective

This study aimed to investigate the clinical efficacy of a balloon compression day-surgery operation under the guidance of spiral computed tomography (CT) three-dimensional (3D) reconstruction for the treatment of trigeminal neuralgia.

Methods

The clinical efficacy and related indexes of 380 patients with trigeminal neuralgia treated by a spiral CT-guided balloon compression day-surgery operation in the pain department of Beijing TianTan Hospital, from October 2017 to March 2021, were retrospectively analyzed.

Results

Five patients failed due to foramen ovale puncture or in placing the balloon; two patients had ineffective results after the operation and re-entered the hospital for secondary balloon compression. The initial effective rate of the operation in the 380 patients was 98.16%. All patients were discharged on the day of the operation, the average operation time was 26.46 ± 12.15 min, and the average interval from the completion of the operation to discharge was 2.67 ± 0.95 h. During the follow-up period (1-41 months), 12 patients had pain recurrence, and a Kaplan-Meier analysis revealed that the cumulative pain-free recurrence survival rate at 41 months after the operation was 80.64%. No complications related to foramen ovale puncture occurred.

Conclusion

The spiral CT-guided balloon compression day-surgery operation is safe, effective, and worthy of clinical promotion.

Efficacy and safety of high-voltage versus standard-voltage pulsed radiofrequency ablation for patients with neuropathic pain: protocol for a systematic review and meta-analysis

INTRODUCTION

Pulsed radiofrequency (PRF) ablation is commonly used for the treatment of neuropathic pain (NP). However, it is unclear whether increasing the output voltage of PRF can safely improve its efficacy. This study aims to compare the efficacy and safety of high-voltage PRF ablation and standard-voltage PRF ablation for the treatment of patients with NP.

METHODS AND ANALYSIS

We will search PubMed/MEDLINE, EMBASE, Web of Science, the Cochrane Library, conference proceedings for relevant abstracts, clinical trials registers (ClinicalTrials.gov) and the WHO's International Clinical Trial Registry Platform (from the date of inception until 15 March 2022). Only randomised controlled trials will be included. Two reviewers (YJ and GF) will independently perform study screening and selection, data extraction, risk-of-bias assessment and quality-of-evidence assessment. The primary outcome of this meta-analysis will be the efficiency rate in patients with NP. The secondary outcomes will include numeric rating scale score, visual analogue scale score, time to take effect, rescue drug dosage, quality of life using the health questionnaire (SF-36) and the incidence of adverse events. Meta-analyses will be conducted using standard meta-analysis software (RevMan V.5.3, The Nordic Cochrane Center, The Cochrane Collaboration, Copenhagen, Denmark).

ETHICS AND DISSEMINATION

The requirement for ethical approval was waived as our systematic review will be based on the published literature. The results of this study will be submitted to a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022297804.

Comparing the efficacy and safety of short-term spinal cord stimulation and pulsed radiofrequency for zoster-related pain: A systematic review and meta-analysis

BACKGROUND

Pulsed radiofrequency (PRF) is a commonly used method for the treatment of zoster-related pain in the clinic. However, PRF therapy has a high recurrence rate and many adverse reactions. Recent studies have shown that short-term spinal cord stimulation (stSCS) can effectively alleviate zoster-related pain. Due to the lack of evidence, it is unclear whether stSCS is superior to PRF in the efficacy of treating zoster-related pain.

OBJECTIVE

This study aimed to compare the efficacy and safety of stSCS and PRF for zoster-related pain.

METHODS

We searched seven electronic databases from the establishment of the database to January 2021. Related randomized controlled trials were included in this meta-analysis. After extracting the data and evaluating the methodological quality of the included trials, the outcome indicators were statistically analyzed by using RevManV.5.3.

RESULTS

This meta-analysis included 6 trials with a total of 509 patients. Compared with PRF group, stSCS group showed lower pain intensity (standardized mean difference=-0.83, 95%CI [-1.37, -0.30], P=.002), better sleep quality (mean difference=-1.43, 95%CI [-2.29, -0.57], P=.001), lower pain rating index scores, and less incidence of adverse events (RR=0.32, 95%CI [0.12, 0.83], P<.05). However, the efficacies of PRF and stSCS for treating postherpetic neuralgia were consistent in the response rate (RR= 1.10, 95% CI [0.82, 1.48], P=.51) and the complete remission rate (RR=1.05, 95% CI [0.66, 1.68], P=.84).

CONCLUSIONS

In this study, stSCS showed a better analgesic effect and higher safety than PRF. Our meta-analysis results suggested that stSCS may be a feasible and safe invasive treatment for zoster-related pain. However, high-quality, randomized controlled trials with large sample sizes are needed to further verify our conclusions.

Effective Treatment of Postherpetic Neuralgia at the First Branch of the Trigeminal Nerve by High-Voltage Pulsed Radiofrequency

Background: Postherpetic neuralgia (PHN) is one of the most common and serious complications of herpes zoster. PHN of the first branch of the trigeminal nerve is painful and difficult to treat, as no definitive effective treatment is available. The aim of this retrospective study was to observe the efficacy and safety of treatment of PHN of the first branch of the trigeminal nerve with high-voltage pulsed radiofrequency (PRF) of the supraorbital nerve.

Methods: Fifty-two patients diagnosed with the PHN of the first branch of the trigeminal nerve at the Department of Pain Management, Shengjing Hospital, China Medical University, between April 2017 and October 2020 were selected. The PRF treatment of the supraorbital nerve was used. The patients were divided into two groups according to the treatment received: group C, conventional PRF group; and group H, high-voltage PRF group. The basic conditions, pain scores, and SF-36 scores of patients before treatment were recorded. Also, intraoperative and postoperative adverse events, visual analog scale (VAS) scores, 36-Item Short Form Health Survey (SF-36) scores at 1 week, 1 month, 3 months, and 6 months of follow-up were recorded. Furthermore, treatment efficiency was followed up at 6 months after treatment.

Results: The VAS scores of patients in both groups were significantly lower at all time points after treatment compared with presurgery. VAS scores in group H were lower than those in group C 1, 3, and 6 months after treatment. SF36 scores of patients in group H were better than those in group C 1, 3, and 6 months after treatment. The treatment efficiency at 6 months after treatment was higher in group H than in group C. No serious adverse events occurred in both groups.

Conclusion: The efficacy of the high-voltage PRF of the supraorbital nerve in treating the PHN of the first branch of the trigeminal nerve was superior to that of conventional PRF. It was a safe and effective treatment method.

Radiofrequency Ablation for Craniofacial Pain Syndromes

Headache disorders and trigeminal neuralgia are common conditions representing the types of craniofacial pain syndrome that can significantly impact quality of life. Many cases are refractory to traditional pharmacologic treatments, whether oral or intravenous. Radiofrequency ablation has been increasingly used as a tool to treat resistant, chronic pain of both of these disorders. Multiple studies have been reported that illustrate the efficacy of radiofrequency ablation in the treatment of the numerous headache subtypes and trigeminal neuralgia.

Effects of High-Voltage Pulsed Radiofrequency on the Ultrastructure and Nav1.7 Level of the Dorsal Root Ganglion in Rats With Spared Nerve Injury

OBJECTIVES

To investigate the analgesic effect of high-voltage pulsed radiofrequency (HV-PRF) on the dorsal root ganglion (DRG) for neuropathic pain induced by spared nerve injury (SNI) in rats, especially the influence of this treatment on the DRG ultrastructure and voltage-gated sodium channel 1.7 (Nav1.7) level in the DRG.

MATERIALS AND METHODS

One hundred fifty adult male Sprague-Dawley rats were randomly divided into five groups: Sham, SNI, Free-PRF, standard-voltage PRF (SV-PRF), and HV-PRF. The 45V-PRF and 85V-PRF procedures applied to the left L5 DRG were performed in SV-PRF group and the HV-PRF group respectively on day 7 after SNI, whereas no PRF was concurrently delivered in Free-PRF group. The paw mechanical withdrawal threshold (PMWT) was detected before SNI (baseline) and on days 1, 3, 7, 8, 10, 14, and 21. The changes of left L5 DRG ultrastructure were analyzed with transmission electron microscopy on days 14 and 21. The expression levels of Nav1.7 in left L5 DRG were detected by immunofluorescence and Western blot.

RESULTS

Compared with the Free-PRF group, PMWT in the SV-PRF group and HV-PRF group were both significantly increased after PRF (all p < 0.05). Meanwhile, the PMWT was significantly higher in the HV-PRF group than that in the SV-PRF group on days 14 and 21 all (p < 0.05). There were statistically significant differences between the SV-PRF and Free-PRF groups (p < 0.05). Similarly, statistically significant difference was found between the HV-PRF and Free-PRF groups (p < 0.05). Especially, comparison of the SV-PRF group and the HV-PRF group revealed statistically significant difference (p < 0.05). The Nav1.7 levels were significantly down-regulated in the SV-PRF group and HV-PRF groups compared to that in the Free-PRF group (all p < 0.01). A significantly lower Nav1.7 level was also found in the HV-PRF group compared to that in the SV-PRF group (p < 0.05).

CONCLUSIONS

The HV-PRF produces a better analgesic effect than SV-PRF applied to the DRG in SNI rats. The underlying mechanisms may be associated with improving the histopathological prognosis and the downregulation of Nav1.7 levels in the DRG.

Therapeutic Efficacy of Ultrasound-Guided High-Voltage Long-Duration Pulsed Radiofrequency for Pudendal Neuralgia

Pudendal neuralgia (PN) is a complex disease with various clinical characteristics, and there is no treatment showing definite effectiveness. This study is aimed at evaluating the clinical efficacy of ultrasound-guided high-voltage long-duration pulsed radiofrequency (PRF) for PN. Two cadavers (one male, one female) were dissected to provide evidence for localization of the pudendal nerve. Patients diagnosed as PN who failed or were intolerant in regular medication were screened for diagnostic local anesthesia block of the pudendal nerve before recruitment. Twenty PN patients were enrolled in this study. In the PRF procedure, the needle tip was inserted medially into the internal pudendal artery under ultrasound guidance. The position of the PRF needle tip was then adjusted by the response of the pudendal nerve to the electrical stimulation within the pudendal area (42°C, a series of 2 Hz, and 20 ms width pulses that lasted for 900 s). Alleviation of pain was assessed by the visual analogue scale (VAS) and sitting time pretreatment and on 7 d, 14 d, 1 m, 2 m, 3 m, and 6 m posttreatment in outpatient follow-up or by telephone interview. Two patients were lost due to intervention-irrelevant reasons. Patients showed significantly decreased VAS scores on 7 d after RFP, compared with pretreatment status (7.0 ± 0.9 vs. 3.2 ± 1.7, P < 0.001). The efficacy remained steady till the end of 6 months, with a final remission rate of 88.9%. Sitting time also significantly lengthened following PRF (7 d, 14 d, 1 m, 2 m, 3 m, and 6 m vs. pretreatment, all P < 0.05). Only short-term ipsilateral involuntary convulsion of the lower extremity was reported in one patient, who recovered within 12 h. Six patients were treated with nonsteroidal drugs for a short time. All patients stopped taking medication finally. In conclusion, the ultrasound-guided high-voltage long-duration PRF approach not only reduced the pelvic pain caused by PN but also improved the quality of life by extending sitting time without nerve injury.

Radiofrequency Treatment of Idiopathic Trigeminal Neuralgia (Conventional vs. Pulsed): A Prospective Randomized Control Study

BACKGROUND

Idiopathic trigeminal neuralgia (TGN) is a chronic pain disorder causing unilateral, severe brief stabbing recurrent pain in the distribution of one or more branches of the trigeminal nerve. Conventional radiofrequency (CRF) and pulsed radiofrequency (PRF) are two types of minimally invasive treatment. CRF selectively ablates the part of ganglion to provide the relief, but it has been found to be associated with some side effects such as dysesthesia or sensory loss in 6%-28% and loss of corneal reflex in 3%-8% of patients. PRF is a comparatively newer modality which is a nondestructive and neuromodulatory method of delivering radiofrequency energy to the gasserian ganglion to produce a therapeutic effect.

AIMS

We aimed to compare the efficacy of CRF with long-duration, fixed voltage PRF in the treatment of idiopathic TGN.

SETTING

This study was conducted in a tertiary care center research institute.

STUDY DESIGN

This was a prospective randomized trial.

MATERIALS AND METHODS

Twenty-seven adult patients of TGN were included in the study and randomly allocated into two groups (CRF and PRF). All procedures were performed operation suite with C-arm fluoroscopic guidance. Both, pre- and postprocedure, the patients were assessed for pain on the Visual Analog Scale (VAS) and Barrow Neurological Institute (BNI) Pain Intensity Scale at 1 week and thereafter at 1, 2, 3, and 6 months. Patients with a BNI score ≥4 after 1 month were considered a failure and offered other modes of treatment. A reduction in VAS score ≥50% and a BNI score <4 were considered as effective.

STATISTICAL ANALYSIS

Discreet variables were recorded as proportions, ordinal variables and continuous variables with non-Gaussian distribution as medians with interquartile range, and continuous variables with Gaussian distribution as mean ± standard deviation. Association between ordinal variables was tested by Fisher's exact test/Chi-square test whenever appropriate. Equality of means/median was tested by using paired/unpaired t-test or nonparametric tests depending upon the distribution of data. P ≤ 0.5 was considered statistically significant. Data analysis was performed using STATA version 13.04 windows.

RESULTS

Efficacy in terms of decrease in VAS ≥50% at 1 month was 33.33% and 83.33% in the PRF and CRF groups, respectively, which was statistically significant(P = 0.036). Effective reduction in BNI scores at the 7th day, 1 month, and 2 months postprocedure was evaluated and found in 41.67% and 83.33% of patients in the PRF and CRF groups, respectively, which was statistically insignificant (P = 0.089). There was a statistically significant reduction in BNI scores in PRF and CRF group patients at 3 and 6 months (at 3 months, 33.33% and 83.33%, P = 0.036 and at 6 months, 25% and 83.33%, P = 0.012). In the CRF group, mild hypoesthesia was evident in three patients which improved by the end of 1 month while no side effects were seen in the PRF group.

CONCLUSION

CRF is a more effective procedure to decrease pain in comparison to long-duration, fixed voltage PRF for the treatment of idiopathic TGN. Although the side effects are more with CRF, they are mild and self-limiting.

Invasive and Non-Invasive Electrical Neuromodulation in Trigeminal Nerve Neuralgia: A Systematic Review and Meta-Analysis

BACKGROUND

Trigeminal neuralgia is a chronic disease characterized by intense facial pain that is caused by trigeminal nerve affectation. It usually affects adults from 50 years of age, and is more frequent in women. Additionally, it presents serious psychological effects that often lead to depression, which is why it is considered highly disabling. The therapeutic approach is based on the modification of nerve activity through electrical, surgical or chemical stimulation in specific regions of the nervous system.

OBJECTIVE

To perform a meta-analysis of the scientific literature related to invasive and non-invasive electrical neuromodulation of trigeminal neuralgia, in order to assess their effects over pain and adverse effects.

METHODS

A literature search was conducted in 4 databases, followed by a manual search of articles on invasive or non-invasive electrical neuromodulation to control the pain of trigeminal neuralgia, including the last 15 years.

RESULTS

Regarding non-invasive methods, clinical trials did not present enough results in order to perform a meta-analysis. Regarding invasive methods, clinical trials meta-analysis showed no statistical differences between different treatment methods. In all cases, improvements in patients' pain were reported, although results regarding adverse effects were variable.

CONCLUSION

In the treatment of trigeminal neuralgia, the continuous radiofrequency provides better short and medium-term results, but pulsed radiofrequency shows less adverse effects after treatment, and has better results in the long-term.

Long-term Inhibition of Soleus H-reflex with Epidural Adhesiolysis and Pulsed Radiofrequency in Lumbosacral Neuropathic Pain

INTRODUCTION

Scientific data about neurophysiological changes subsequent to pulsed radiofrequency (PRF) are still lacking. The goal of this study was to evaluate sural nerve conduction and Hoffmann reflex (H-reflex) in soleus muscle following adhesiolysis and PRF in patients with unilateral chronic lumbosacral L5-S1 neuropathic radiating pain.

METHODS

Seventeen patients received two cycles of 240 seconds high-voltage PRF and epidural adhesiolysis. Sural nerve action potential (SNAP) and the ratio of maximum H-reflex to maximum M response (H/M ratio) as well as pain scores were collected in both lower limbs before, immediately following, and 1 month after the treatment.

RESULTS

At follow-up, a significant reduction in numeric rating scale (NRS) and Douleur Neuropathique 4 Questions (DN4) scores was observed in 53% of patients reporting pain improvement of ≥ 30% over baseline. The H/M ratio was decreased in the affected limb following PRF (P = 0.01) and 1 month after the treatment (P = 0.04). A direct correlation was observed between H/M ratio variation and NRS score at follow-up in the treated limb (P = 0.04). No significant difference in sural nerve latency, amplitude, and velocity was detected between affected and normal side after treatment and at follow-up.

CONCLUSIONS

Epidural adhesiolysis and PRF of the dorsal root ganglion seem to significantly affect spinal reflexes in patients with lumbosacral neuropathic radiating pain.

Pulsed radiofrequency alleviated neuropathic pain by down-regulating the expression of substance P in chronic constriction injury rat model

Background

Pulsed radiofrequency (PRF), as a non-invasive treatment of neuropathic pain (NP), has been widely administered clinically. Previous studies have shown that PRF has the potential to improve hyperalgesia in animal models of NP. However, there have been few reports to clarify whether the mechanism of PRF treatment of NP involves intervention in the expression of substance P (SP). Therefore, this study administered PRF treatment to chronic constriction injury (CCI) model rats and observed the sciatic nerve mechanical pain threshold and SP expression in the spinal cord to explore the mechanism of PRF treatment.

Methods

A total of 96 Sprague-Dawley rats were randomly divided into the sham-surgery-sham-treatment group (S-S group), the sham-surgery-PRF group (S-P group), the CCI-sham-treatment group (C-S group), and the CCI-PRF group (C-P group). The C-S group and the C-P group underwent sciatic nerve CCI, while the other groups received a sham operation. At 14 days after the operation, the C-P group and the S-P group were treated with PRF for 300 s. We recorded the hindpaw withdrawal threshold (HWT) and the thermal withdrawal latency (TWL) of rats in the various groups at baseline, before treatment (0 days), and at 1, 7, 14, and 28 days after treatment. L4 to L6 spinal cord tissues were taken before treatment (0 days) and 1, 7, 14, and 28 days after treatment. The transcription and translation of SP were measured by quantitative polymerase chain reaction and Western blotting, respectively.

Results

The HWT and the TWL in the C-P group 28 days after PRF treatment were significantly higher than those in the C-S group (95% confidence interval [CI]: 5.84–19.50, P < 0.01; 95% CI: 2.58–8.69, P = 0.01). The expression of SP in the C-P group 28 days after PRF treatment was significantly lower than that in the C-S group (95% CI: 1.17–2.48, P < 0.01).

Conclusions

PRF may alleviate CCI-induced NP by down-regulating the expression of SP in the spinal cord of CCI model rats.

The Long-Term Outcome of CT-Guided Pulsed Radiofrequency in the Treatment of Idiopathic Glossopharyngeal Neuralgia: A Retrospective Multi-Center Case Series

Background

Safer and minimal invasive treatment options with minor side effects are in great demand in the treatment of glossopharyngeal neuralgia (GPN). Pulsed radiofrequency (PRF) is a micro-destructive procedure that could be applied repeatedly without irreversible damage to target tissue. However, few studies have reported the long-term clinical outcomes of PRF in the management of idiopathic GPN patients.

Methods

We retrospectively investigated the efficacy and safety of computed tomography (CT)-guided PRF in the treatment of 30 patients with idiopathic GPN in a multi-center clinical study. Numeric rating scale (NRS) score was used to evaluate pain intensity before and after PRF treatment. The effective rate was defined as the percentage of patients with NRS reduction of more than 50%. Baseline characteristics, surgical records, initial pain relief, time to take effect, long-term outcomes, patient satisfaction using a five-level Likert Scale, the incidence of recurrence as well as subsequent treatment choices, intraoperative and postoperative complications were retrieved from electronic medical records.

Results

A total of 30 idiopathic GPN patients who received PRF under CT-guidance were included in our study and the initial effective rate was 93.3%. The cumulative proportion of patients with satisfactory pain relief survival was 93.3% at 12 months, 89.6% at 24 months, 85.3% at 36 months, 79.6% at 48 months, 73.0% at 60 months and 72 months, and 54.8% at 84 months, 108 months as well as 120 months. No serious morbidity or mortality were observed in any of the cases. The median patient satisfaction in Likert scale rating was 4.0 (IQR, 3.0–5.0).

Conclusion

According to our results, PRF is an effective and safe therapy for patients with idiopathic GPN. This minimally invasive, micro-destructive, neuro-modulatory technique could be a potential intervention of choice for the treatment of GPN patients who respond poorly to pharmacological treatment.

Predictors of the Analgesic Efficacy of CT-Guided Percutaneous Pulsed Radiofrequency Treatment of Gasserian Ganglion in Patients With Idiopathic Trigeminal Neuralgia

AIMS

Although pulsed radiofrequency (PRF) has few postoperative adverse reactions, its analgesic efficacy for trigeminal neuralgia (TN) is not always guaranteed. The response rate of PRF targeting the Gasserian ganglion for patients with TN varies. This study aims to identify the predictors of the analgesic efficacy of CT-guided percutaneous PRF in patients with idiopathic TN.

METHODS

The patients with idiopathic TN who failed to respond to conservative treatment and underwent CT-guided percutaneous PRF treatment of the Gasserian ganglion from July 2008 to August 2018 at our pain clinic were screened. A positive response was defined as a ≥50% reduction in the pain numeric rating scale (NRS) score from baseline. The demographics and other pretreatment clinical data were analyzed by logistic regression analysis to identify the predictors of a positive response.

RESULTS

Of the total 102 patients with idiopathic TN who were evaluated in this study, 57 patients (55.9%) were positively responsive to our treatment after 1 year. The binary logistic regression analysis revealed that the positive response to a prior peripheral branch nerve block of the trigeminal nerve with steroid and local anesthetic agents was an independent predictor of the analgesic efficacy of PRF treatment (odds ratio [OR] = 3.685, 95% confidence interval [CI] = 1.583 to 8.577, P = 0.002). The disease duration of TN was also included in the multivariate regression model, although the P value was 0.058 (OR 0.807, 95% CI 0.646 to 1.007).

CONCLUSION

For patients who previously had positive responses to peripheral branch nerve block of the trigeminal nerve, PRF is likely to have better efficacy.

A prospective case series of sphenopalatine ganglion pulsed radiofrequency therapy for refractory chronic cluster headache

BACKGROUND AND PURPOSE

The management options for chronic cluster headache (CCH) are limited and a significant proportion of patients become refractory to pharmacological treatments. Pulsed radiofrequency (PRF) of the sphenopalatine ganglion (SPG) may present an efficacious, minimally invasive treatment modality for patients with refractory CCH. We describe the clinical outcomes of 14 patients with refractory CCH treated with PRF of the SPG.

METHODS

Patients with medically refractory CCH who underwent percutaneous SPG-PRF treatment between January 2016 and April 2019 were included in this report. Patients obtaining at least 30% reduction in weekly cluster attacks for at least 3 months were defined as responders. Treatment-related side effects were collected.

RESULTS

A total of 14 patients were included in this report (nine males). At a median follow-up of 6.5 (range 6-13) months post-procedure, eight patients (57.1%) were defined as responders to the treatment. Six patients were non-responders and reported either a reduction in frequency and severity of attacks for <3 months (2/6), no improvement (2/6) or temporary worsening of symptoms (1/6). The majority of patients (63.6%, n = 7/11) treated with >45 V were responders compared with responders treated with 45 V (33.3%, n = 1/3). Five patients (35.7%) experienced post-procedural side effects.

CONCLUSION

This case series suggests that PRF targeting the SPG might offer a safe, minimally invasive and effective treatment for medically refractory CCH. Given the small number of cases and the short follow-up, larger and more robust studies will be needed to confirm our findings.

Treatment Outcomes in Trigeminal Neuralgia-A Systematic Review of Domains, Dimensions and Measures

BACKGROUND

Trigeminal neuralgia (TN) is a painful disorder characterized by sudden electric shock-like pain. It is a rare condition for which multiple treatments are available, including medical and surgical. The best treatment option is yet to be defined, and this is related to the lack of definition in the treatment outcomes and outcome measures. The aim of this systematic review was to summarize all the outcomes and outcomes measures that have been published to date and highlight variability in their use.

METHODS

We have conducted a literature search using a wide range of databases (1946-2019 for medical and 2008-2019 for surgical treatment), for all intervention studies in TN. Four hundred and sixty-seven studies were selected for data extraction on TN classification, data collection method, intervention, and treatment outcomes mapped to the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT guidelines).

RESULTS

Most studies collected data on pain (n = 459) and side effects (n = 386) domains; however, very few collected data on the impact of treatment on physical (n = 46) and emotional functioning (n = 17) and on patient satisfaction (n = 35). There was high variability on outcome measures used for pain relief (n = 10), pain intensity (n = 9), and frequency of pain episodes (n = 3).

CONCLUSIONS

A clear definition of what are the important outcomes for patients with TN is essential. The choice of standardized outcome measures allowing for consistent reporting in TN treatment will allow for comparison of studies and facilitate treatment choice for patients and clinicians thus, improving health outcomes and reducing health care cost.

Long-Term Efficacy and Complications of Radiofrequency Thermocoagulation at Different Temperatures for the Treatment of Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a common neuropathic pain that seriously affects the daily life of patients. Many invasive treatments are currently available for patients who respond poorly to oral carbamazepine or oxcarbazepine. Among them, radiofrequency (RF) treatment is a viable option with reliable initial and long-term clinical efficacy. The long-term analgesic effects of radiofrequency thermocoagulation (RFT) at high temperatures (≥80°C) are not superior to those at relatively low temperatures (60–75°C). In contrast, the higher the temperature, the greater the risk of complications, especially facial numbness, masticatory muscles weakness, and corneal hypoesthesia. Some patients even experience irreversible lethal complications. Therefore, we recommend low-temperature RFT (60–75°C) for treatment of TN. The therapeutic effects of pulsed radiofrequency (PRF) are controversial, whereas PRF (≤75°C) combined with RFT can improve long-term effects and decrease the incidence of complications. However, large-scale clinical trials are needed to verify the efficacy of the combination of PRF and RFT.

Pulsed Radiofrequency of C2 Dorsal Root Ganglion Under Ultrasound-Guidance and CT Confirmed for Chronic Headache: Follow-Up of 20 Cases and Literature Review

Background

Chronic headache is common but difficult to treat. Most patients respond poorly to drugs. Nerve block is an effective treatment but has no continuous effect. The pulsed radiofrequency (PRF) technique has been shown to be effective in relieving head pain and extending the effect of nerve block.

Objective

The purpose of this study is to evaluate the long-term efficacy of C2 dorsal root ganglion after pulsed radiofrequency (PRF) guided by ultrasound for chronic headache.

Setting

The Department of Pain Management, West China Hospital.

Methods

Twenty patients who did not respond to medications and peripheral nerve blocks underwent ultrasound-guided PRF of the C2 dorsal root ganglion. The patients were followed up for 6 months. Visual analog scale (VAS) score was evaluated at 1 week, 1 month, 3 months, and 6 months. The quality of life (QOL) was assessed by Brief Pain Inventory (BPI) scores which were rated at pre-procedure and 1 month, 3 months, and 6 months after the procedure. The occurrence of complications was evaluated and reported.

Results

Mean VAS scores were significantly decreased at 1 week, 1 month, 3 months and 6 months compared to the pre-procedure mean VAS score. Mean BPI scores decreased significantly at each postoperative time point compared to the preoperative baseline and low scores remained throughout the follow-up period: 45.05±3.44 at pre-procedure, 10.60 ± 2.37 at 1 weeks, 12.50 ± 2.46 at 1 month, 12.90 ± 2.62 at 3 months, and 11.63 ± 2.98 at 6 months. Mild complications occurred, including 1 case (4.7%) of transient cervicalgia (lasting for 24 hrs) and 3 cases (14.2%) of transient dizziness (lasting for 30 mins).

Limitations

Firstly, it included a small sample of patients. Another is the short duration of the follow-up.

Conclusion

C2 PRF may be considered as an alternative treatment for chronic headache.

Electrocatheter-mediated High-voltage Pulsed Radiofrequency of the Dorsal Root Ganglion in the Treatment of Chronic Lumbosacral Neuropathic Pain: A Randomized Controlled Study

OBJECTIVES

Despite the interest in scientific community, there is still poor evidence about pulsed radiofrequency (PRF) efficacy in the treatment of neuropathic pain. In order to determine whether high-voltage PRF and epidural adhesiolysis (PRF-EA) showed better results than epidural adhesiolysis alone (EA), a randomized, double-blind, comparative-effectiveness study was conducted in patients with chronic lumbosacral radiating pain and neuropathic features.

MATERIALS AND METHODS

A total of 41 patients were randomly allocated to 2 groups. Twenty-one patients were randomized to receive 2 cycles of 240 seconds high-voltage PRF followed by the injection of local anesthetics, hyaluronidase, and betamethasone, whereas 20 patients underwent sham stimulation followed by adhesiolysis. The treatment was delivered at the affected lumbosacral roots and patients, treating physicians and assessors were blinded to intervention.

RESULTS

A significant reduction of radiating pain was observed in mean Numeric Rating Scale score at follow-up. A change of -3.43 versus -1.75 (P=0.031) after 1 month and -3.34 versus -0.80 (P=0.005) after 6 months was reported in patients undergoing PRF-EA in comparison with EA, respectively. After 1 month, 57% of patients in the PRF-EA group experienced a pain reduction of ≥50% versus only 25% of patients allocated to EA (P=0.037). Improvement decreased to 48% in the PRF-EA group whereas only 10% of EA reported significant pain relief after 6 months (P=0.008).

DISCUSSION

High-voltage PRF of dorsal root ganglion delivered through multifunctional electrode provided significant pain relief and may be considered a valuable treatment in chronic lumbosacral radicular pain with neuropathic features.

Combined pulsed and thermal radiofrequency versus thermal radiofrequency alone in the treatment of recurrent trigeminal neuralgia after microvascular decompression: A double blinded comparative study

BACKGROUND

Recurrent trigeminal neuralgia (RTN) is a common clinical problem and pain recurs in many patients after microvascular decompression (MVD). We evaluated the effect of adding pulsed radiofrequency to radiofrequency thermocoagulation at 60°C compared to radiofrequency thermocoagulation at 70°C alone in the treatment of recurrent trigeminal neuralgia after microvascular decompression.

METHODS

40 patients with recurrent trigeminal neuralgia after microvascular decompression were randomly divided into two equal groups. Group A: received prolonged duration of pulsed radiofrequency followed by less destructive thermocoagulation, while group B: received sole thermocoagulation. Then patients followed up for 2 years to evaluate the success rate by the Barrow Neurological Institute Pain Intensity (BNI) Scale, complications, and the need to medical treatment.

RESULTS

The success rate was 100% in both groups at discharge (BNI < III). It was 83.3% and 78.7% after 6 months, 77.8% and 68.4% after 12 month, 72.2% and 68.4% after 18 months and 66.7% and 63.1% after 24 months in group A and B, respectively (p > .05). In group A 88.9% of patients stopped tegretol treatment after the procedure compared to 84.2% in group B (p = .32). 88.9% compared to 89.5% % in group A and B, respectively, did not use tricyclic antidepressant (p = .61). The overall complications in group A was 5.61%, while it was 36.8% in group B (p = .025).

CONCLUSION

Combined pulsed and thermal radiofrequency can significantly reduce the incidence of the side effects/complications with similar success rate than using thermal radiofrequency alone in treatment of recurrent trigeminal neuralgia after microvascular decompression.

Therapeutic efficacy and safety of radiofrequency ablation for the treatment of trigeminal neuralgia: a systematic review and meta-analysis

Objective

The objective of this study was to summarize the effectiveness and safety of trigeminal neuralgia (TN) treatment via different radiofrequency approaches such as continuous radiofrequency (CRF), pulsed radiofrequency (PRF), and combined CRF and pulsed radiofrequency (CCPRF) treatments, thus providing high-quality clinical evidence for TN treatment.

Methods

A series of databases were searched for relevant articles published between January 1998 and April 2018. The modified Jadad scale was referred to evaluate the methodological quality of the included studies. Data were extracted independently, and the outcome and safety of different routes, temperatures, and guidance used in CRF, PRF, and CCPRF were compared. Meta-analysis and publication bias were calculated using Review Manager software.

Results

In total, 34 studies involving 3,558 participants were included. With regard to TN treatment, PRF had no difference in cured rate in comparison with CRF, while CRF was more effective than CCPRF (P<0.05). The comparison of complication rates showed that PRF and CCPRF were safer. For puncture guidance via CRF, three-dimensional-printed template was more accurate in success rate at first puncture than computed tomography guidance (P<0.05). For puncture route, foramen rotundum (FR) or pterygopalatine fossa (PPF) route had no significance in efficiency rate via CRF in comparison with foramen oval (FO) route, but PPF and FR routes were safer. For CRF treatment, low temperature (68°C-70°C) compared with high temperature (71°C-75°C) had no effect. Moreover, higher temperature (66°C-80°C) had a greater effect compared with lower temperature (55°C-65°C) on TN treatment (P<0.05), while the safety of which was decreasing.

Conclusion

CCPRF could achieve a greater effect and safety on TN treatment. FR and FO routes in TN puncture treatment via CRF are safer. Medium temperature range is better for CRF therapy, and higher temperature is recommended in PRF, especially for the elders. Further international multicenter trials are needed to confirm the evidence.

Efficacy and safety of CT-guided percutaneous pulsed radiofrequency treatment of the Gasserian ganglion in patients with medically intractable idiopathic trigeminal neuralgia

Background

There is a lack of prospective studies for the long-term results of percutaneous pulsed radiofrequency (PRF) of the Gasserian ganglion in the treatment of patients with medically refractory trigeminal neuralgia (TN).

Methods and results

We prospectively observed the outcomes of 28 idiopathic TN patients (between July 2013 and July 2016) who received CT-guided percutaneous PRF treatment of the Gasserian ganglion. All of the patients had stopped responding to drug therapy before PRF treatment. The effective treatment standard was a reduction in the pain numeric rating scale (NRS) by ≥50% after the procedure. The postoperative NRS score decreased gradually from preoperative 7.6±0.8 months to 1.5±2.4, 0.2±0.4, 0.2±0.4, 0.1±0.4, and 0.1±0.4 at 1, 3, and 6 months and 1 and 2 years after the PRF treatment. The response rates at 1, 3, and 6 months were 85.7%, and the rates at 12 months and 2 years were maintained at 78.6%. No serious side effects were observed.

Conclusion

CT-guided PRF invention is an effective and safe technique for medically intractable idiopathic TN patients. This minimally invasive alternative treatment has the potential as a first-line therapy for TN.

Pulsed radiofrequency of C2 dorsal root ganglion under ultrasound guidance for chronic migraine: a case report

Chronic migraine is common but difficult to treat. Most patients respond poorly to drugs. Occipital nerve block such as stellate ganglion block is an effective treatment without continuous effect for migraine. Pulsed radiofrequency (PRF) technique has been shown to be effective in relieving headache and prolonging the effect of nerve block. This case report is about a patient who suffered from chronic migraine with occipital pain and was successfully treated with PRF of C2 (axis) dorsal root ganglion (DRG) under ultrasound guidance confirmed by computed tomograpy scan. The patient did not feel headache after 1-year follow-up. This suggests that C2 DRG PRF might be considered as an alternative treatment for chronic migraine with occipital pain.

Pulsed radiofrequency in chronic pain

PURPOSE OF REVIEW

The increasing number of publications on pulsed radiofrequency (PRF) treatment of chronic pain reflects the interest for this technique. We summarize the literature for PRF in five indications: radicular pain, trigeminal neuralgia (TN), occipital neuralgia, shoulder and knee pain.

RECENT FINDINGS

The efficacy and safety of PRF adjacent to the dorsal root ganglion was documented on cervical and on lumbar level.PRF has been used for the treatment of TN. The observed duration of effect is shorter than that of conventional radiofrequency, but no neurological complications are reported with PRF.PRF of the nervi occipitales is superior to steroid injections in occipital neuralgia.Several studies showed that PRF of the nervus suprascapularis may relief shoulder pain and can improve mobility of the shoulder joint.For the treatment of knee pain, different nerves have been targeted for PRF treatment.

SUMMARY

PRF treatment has progressively gained a place in the management of chronic pain syndromes. The concept is appealing because long-lasting effects are reported without complications. Future research is needed with high quality randomized controlled trials and identification of the optimal parameters of PRF in clinical practice.

Interventions for Refractory Trigeminal Neuralgia: A Bayesian Mixed Treatment Comparison Network Meta-Analysis of Randomized Controlled Clinical Trials

INTRODUCTION

Patients with trigeminal neuralgia (TN) are often refractory to recommended first-line agents. Due to the absence of a systematic review, we undertook a network meta-analysis to assess various interventions that can be used to manage refractory TN.

METHODS

Electronic databases were searched using appropriate strategies to identify randomized controlled clinical trials in patients with refractory TN, evaluating the proportion of patients with a minimum of 50% reduction in pain or a minimum of 2 cm reduction in score in an appropriate pain scale or complete pain relief by subjective pain scales. Mixed treatment comparisons were carried out using a Bayesian approach and a random-effects model was developed with Monte-Carlo simulation with 1,000 iterations. Odds ratios with 95% credible intervals were assessed for each comparison. Consistency of direct and indirect results was checked with deviance plots. Rankogram was generated based on the surface area under the cumulating ranking curve (SUCRA).

RESULTS

A total of 13 studies were included in this systematic review, of which 11 were finally included for the final network meta-analysis. Two different interventions were analyzed: drug-related and radiofrequency related interventions. In the former group, sumatriptan, intranasal lidocaine, botulinum toxin, and intravenous lidocaine were observed to perform better than ophthalmic proparacaine and placebo based on pooled estimates in a Forest plot. In the latter group, conventional radiofrequency (both standalone and in combination with pulsed radiofrequency) was found to be better than pulsed radiofrequency alone. Rankogram plots revealed sumatriptan and combined continuous and pulsed radiofrequency thermocoagualtion have the highest probability of being the best treatments in the respective group of interventions. No inconsistency was observed between direct and indirect comparisons.

CONCLUSION

We found that drug-related interventions that include sumatriptan, intranasal lidocaine, intravenous lidocaine, and botulinum toxin and combined continuous and pulsed radiofrequency thermocoagulation had significant effects in reducing pain in patients with refractory TN. However, the quality of evidence was graded as very low for all except botulinum toxin.

Treatment of Refractory Idiopathic Supraorbital Neuralgia Using Percutaneous Pulsed Radiofrequency

BACKGROUND AND AIMS

No ideal therapeutic method currently exists for refractory idiopathic supraorbital neuralgia patients who do not respond to conservative therapy, including medications and nerve blocks. Pulsed radiofrequency is a neuromodulation technique that does not produce sequelae of nerve damage after treatment. However, the efficacy of percutaneous pulsed radiofrequency for the treatment of refractory idiopathic supraorbital neuralgia is still not clear. The purpose of our study was to evaluate the efficacy and safety of pulsed radiofrequency treatment of the supraorbital nerve for refractory supraorbital neuralgia patients.

METHODS

We prospectively investigated the long-term effects of ultrasound-guided percutaneous pulsed radiofrequency in the treatment of 22 refractory idiopathic supraorbital neuralgia patients. A reduction in the verbal pain numeric rating scale score of more than 50% was used as the standard of effectiveness. The effectiveness rates at different time points within 2 years were calculated.

RESULTS

After a single pulsed radiofrequency treatment, the effectiveness rate at 1 and 3 months was 77%, and the rates at 6 months, 1 year, and 2 years were 73%, 64%, and 50%, respectively. Except for a small portion of patients (23%) who experienced mild upper eyelid ecchymosis that gradually disappeared after approximately 2 weeks, no obvious complications were observed.

CONCLUSIONS

In conclusion, the results of our study demonstrate that for patients with refractory idiopathic supraorbital neuralgia, percutaneous pulsed radiofrequency may be an effective and safe treatment choice.

Pulsed Radiofrequency Applied to the Sciatic Nerve Improves Neuropathic Pain by Down-regulating The Expression of Calcitonin Gene-related Peptide in the Dorsal Root Ganglion

Background: Clinical studies have shown that applying pulsed radiofrequency (PRF) to the neural stem could relieve neuropathic pain (NP), albeit through an unclear analgesic mechanism. And animal experiments have indicated that calcitonin gene-related peptide (CGRP) expressed in the dorsal root ganglion (DRG) is involved in generating and maintaining NP. In this case, it is uncertain whether PRF plays an analgesic role by affecting CGRP expression in DRG. Methods: Rats were randomly divided into four groups: Groups A, B, C, and D. In Groups C and D, the right sciatic nerve was ligated to establish the CCI model, while in Groups A and B, the sciatic nerve was isolated without ligation. After 14 days, the right sciatic nerve in Groups B and D re-exposed and was treated with PRF on the ligation site. Thermal withdrawal latency (TWL) and hindpaw withdrawal threshold (HWT) were measured before PRF treatment (Day 0) as well as after 2, 4, 8, and 14 days of treatment. At the same time points of the behavioral tests, the right L4-L6 DRG was sampled and analyzed for CGRP expression using RT-qPCR and an enzyme-linked immunosorbent assay (ELISA). Results: Fourteen days after sciatic nerve ligation, rats in Groups C and D had a shortened TWL (P<0.001) and a reduced HWT (P<0.001) compared to those in Groups A and B. After PRF treatment, the TWL of the rats in Group D gradually extended with HWT increasing progressively. Prior to PRF treatment (Day 0), CGRP mRNA expressions in the L4-L6 DRG of Groups C and D increased significantly (P<0.001) and were 2.7 and 2.6 times that of Group A respectively. ELISA results showed that the CGRP content of Groups C and D significantly increased in comparison with that of Groups A and B (P<0.01). After PRF treatment, the mRNA expression in the DRG of Group D gradually decreased and the mRNA expression was 1.7 times that of Group A on the 4th day(P> 0.05). On the 8^th and 14^th days, the mRNA levels in Group D were restored to those of Groups A and B. Meanwhile, the CGRP content of Group D gradually dropped over time, from 76.4 pg/mg (Day 0) to 57.5 pg/mg (Day 14). Conclusions: In this study, we found that, after sciatic nerve ligation, rats exhibited apparent hyperalgesia and allodynia, and CGRP mRNA and CGRP contents in the L4-L6 DRG increased significantly. Through lowering CGRP expression in the DRG, PRF treatment might relieve the pain behaviors of NP.

Pulsed radiofrequency of brachial plexus under ultrasound guidance for refractory stump pain: a case report

The post-amputation (pain) syndrome, including stump pain, phantom limb sensation, and phantom limb pain is common but difficult to treat. Refractory stump pain in the syndrome is an extremely challenging and troublesome clinical condition. Patients respond poorly to drugs, nerve blocks, and other effective treatments like spinal cord stimulation and surgery. Pulsed radiofrequency (PRF) technique has been shown to be effective in reducing neuropathic pain. This report describes a patient with persistent and refractory upper limb stump pain being successfully relieved with PRF of brachial plexus under ultrasound guidance after a 6-month follow-up period, suggesting that PRF may be considered as an alternative treatment for refractory stump-neuroma pain.

Radiofrequency thermocoagulation for V2/V3 idiopathic trigeminal neuralgia: effect of treatment temperatures on long-term clinical outcomes: A Cohort Study

Radiofrequency thermocoagulation (RFT) is widely used to treat trigeminal neuralgia (TN); however, the optimal temperature at which RFT is most efficacious remains under much debate. Thus, the aim of the present study was to determine the lowest temperature at which morbidity could be minimized and patient outcomes maximized.A multivariate analysis was used to study 1354 patients who underwent computed tomography (CT)-guided RFT for V2/V3 idiopathic trigeminal neuralgia (ITN) during from June 2006 to May 2015. RFT was carried out at 62, 65, and 68°C, while keeping all other RF parameters the same. This was a prospective cohort study, in which we assessed intra- and postoperative complications, pain relief, and long-term health-related quality of life (HRQoL).The intraoperative and in-hospital complications of patients were mainly facial hematoma, mouth and external auditory meatus penetration, nausea, vomiting, dizziness, and headache, which were all treated symptomatically. In long-term follow-up, patients with pain relief (defined as no pain and no required drug intervention) at 62, 65, and 68°C accounted for 94.2%, 98.3%, and 98.8% (at discharge); 83.8%, 90.1%, and 91.4% (at 1 year); 66.7%, 80.5%, and 88.2% (at 3 years); 59.0%, 64.3%, and 77.2% (at 5 years); 48.7%, 57.8%, and 72.3% (at 7 years); 40.6%, 53.7%, and 60.3% (at 9 years), respectively. The number of patients with facial numbness, masticatory atonia, or corneal hypoesthesia was increased with the elevation of temperature, but these complications were all mild. No blindness, deafness, intracranial hemorrhage, or death as a result of the surgical intervention occurred in any patients. SF-36 scores showed highest HRQoL in the group treated at 68°C, followed by the 65 and 62°C groups, respectively.Our results demonstrate that 68°C is a good choice for RFT of V2/V3 ITN. The alternative option is 65 or 62°C for RFT to minimize the occurrence of complications including facial numbness, yet which often yields a higher recurrence rate.