Comparing the efficacy and safety of high-voltage and standard-voltage pulsed radiofrequency for the treatment of postherpetic neuralgia: A pooled analysis from randomized controlled trials

Postherpetic neuralgia (PHN) is one of the most common and serious complications of herpes zoster infection. Pulsed radiofrequency (PRF) therapy has emerged to be a neuromodulation technique for the treatment of PHN. Two therapeutic options are available for PRF, including high-voltage and standard-voltage PRF. Some studies suggested that the former one had better clinical efficacy than the latter one. For the first time, this pooled analysis compared the efficacy and safety of these two surgeries for the treatment of PHN. Five commonly used databases were applied to identify the eligible studies. This study was registered on the PROSPERO (ID: CRD42023460236), which provided more relevant information. Finally, four randomized controlled trials (RCTs) with 285 participants were included. The combined odds ratios (OR) showed that high-voltage PRF exhibited a significantly higher treatment efficiency than the standard PRF (OR = 1.4, 95%CI: 1.16 to 1.69, P < 0.001). Additionally, the visual analogue scale (VAS) in the high-voltage PRF group was significantly lower than that of the standard PRF group at one week (SMD = -0.776, 95%CI: -1.408 to -0.145, P = 0.016), one month (SMD = -0.544, 95%CI: -0.907 to -0.180, P = 0.003), and three months (SMD = -1.096, 95%CI: -1.504 to -0.687, P < 0.001) after treatment, particularly at the three months after surgery. However, the VAS was comparable between the two groups (SMD = -0.94, 95%CI: -1.985 to 0.104, P = 0.077). Patients who underwent high-voltage PRF did not have a significantly higher incidence of adverse events than those with standard PRF (OR = 1.56, 95%CI: 0.78 to 3.13, P = 0.208). In summary, the current study revealed that high-voltage PRF is superior to standard-voltage PRF in improving analgesic efficacy in patients with PHN. Additionally, it does not increase the incidence of treatment-related adverse effects. Further studies are still warranted to determine the optimal voltage and duration of PRF treatment for patients with PHN.

Efficacy of ganglion impar block combined with pudendal nerve pulsed radiofrequency for pudendal neuralgia management-a randomized clinical trial

BACKGROUND

Pudendal neuralgia is a chronic and debilitating condition. Its prevalence ranges from 5 to 26%. Currently, therapeutic approaches to treat pudendal neuralgia include patient education, medication management, psychological and physical therapy, and procedural interventions, such as nerve block, trigger point injections, and surgery. Drug therapy has a limited effect on pain relief. A pudendal nerve block may cause a significant decrease in pain scores for a short time; however, its efficacy significantly decreases over time. In contrast, pudendal nerve pulsed radiofrequency can provide pain relief for 3 months, and ganglion impar block has been widely used for treating chronic perineal pain and chronic coccygodynia. This study aimed to determine the efficacy and safety of monotherapy (pudendal nerve pulsed radiofrequency) and combination therapy (pudendal nerve pulsed radiofrequency plus ganglion impar block) in patients with pudendal neuralgia.

METHODS

This randomized, controlled clinical trial will include 84 patients with pudendal neuralgia who failed to respond to drug or physical therapy. Patients will be randomly assigned into one of the two groups: mono or combined treatment groups. The primary outcome will be a change in pain intensity measured using the visual analog scale. The secondary outcomes will include a Self-Rating Anxiety Scale score, Self-Rating Depression Scale score, the use of oral analgesics, the Medical Outcomes Study Health Survey Short Form-36 Item score, and the occurrence of adverse effects. The study results will be analyzed using intention-to-treat and per-protocol analyses. Primary and secondary outcomes will be evaluated between the mono and combined treatment groups. Subgroup analyses will be conducted based on the initial ailment, age, and baseline pain intensity. The safety of the treatment will be assessed by monitoring adverse events, which will be compared between the two groups.

DISCUSSION

This study protocol describes a randomized, controlled clinical trial to determine the efficacy and safety of mono and combination therapies in patients with pudendal neuralgia. The study results will provide valuable information on the potential benefits of this combination therapy and contribute to the development of more effective and safer treatments for patients with pudendal neuralgia.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR2200061800).

Predictive value of S100B and brain derived neurotrophic factor for radiofrequency treatment of lumbar disc prolapse

BACKGROUND

This work aimed to analyze serum S100B levels and brain-derived neurotrophic factor (BDNF) in patients with lumbar disc prolapse to test their predictive values concerning the therapeutic efficacy of pulsed radiofrequency.

METHODS

This prospective interventional study was carried out on 50 patients candidates for radiofrequency for treating symptomatic lumbar disc prolapse. Pain severity and functional disability were assessed using the Numeric Rating Scale (NRS) and Functional rating index (FRI) before as well as two weeks, 1, 3, and 6 months after the radiofrequency. Quantitative assessment of serum S100B level and BDNF was done for all the included patients one day before radiofrequency.

RESULTS

The scores of NRS and FRI were significantly improved at two weeks, 1, 3, and 6 months following radiofrequency (P-value < 0.001 in all comparisons). Statistically significant positive correlations were found between duration of pain, NRS, and S100B serum level before radiofrequency, and both NRS (P-value = 0.001, 0.035, < 0.001 respectively) and FRI (P-value = < 0.001, 0.009, 0.001 respectively) 6 months following radiofrequency. Whereas there were statistically significant negative correlations between BDNF serum level before radiofrequency and both NRS and FRI 6 months following radiofrequency (P-value = 0.022, 0.041 respectively). NRS and S100B serum levels before radiofrequency were found to be independent predictors of NRS 6 months following radiofrequency (P-value = 0.040. <0.001, respectively).

CONCLUSION

Serum level of S100B is a promising biomarker that can predict functional outcomes after pulsed radiofrequency in patients with lumbar disc prolapse.

Accuracy of augmented reality-guided needle placement for pulsed radiofrequency treatment of pudendal neuralgia: a pilot study on a phantom model

Background

Pudendal neuralgia (PN) is a chronic neuropathy that causes pain, numbness, and dysfunction in the pelvic region. The current state-of-the-art treatment is pulsed radiofrequency (PRF) in which a needle is supposed to be placed close to the pudendal nerve for neuromodulation. Given the effective range of PRF of 5 mm, the accuracy of needle placement is important. This study aimed to investigate the potential of augmented reality guidance for improving the accuracy of needle placement in pulsed radiofrequency treatment for pudendal neuralgia.

Methods

In this pilot study, eight subjects performed needle placements onto an in-house developed phantom model of the pelvis using AR guidance. AR guidance is provided using an in-house developed application on the HoloLens 2. The accuracy of needle placement was calculated based on the virtual 3D models of the needle and targeted phantom nerve, derived from CBCT scans.

Results

The median Euclidean distance between the tip of the needle and the target is found to be 4.37 (IQR 5.16) mm, the median lateral distance is 3.25 (IQR 4.62) mm and the median depth distance is 1.94 (IQR 7.07) mm.

Conclusion

In this study, the first method is described in which the accuracy of patient-specific needle placement using AR guidance is determined. This method could potentially improve the accuracy of PRF needle placement for pudendal neuralgia, resulting in improved treatment outcomes.

Pulsed radiofrequency on peripheral nerve as a rehabilitation aid

The work described below explores the field of the effects of pulsed radiofrequency for pain relief purposes. While the effects of this technique on pain modulation (A-delta and C fibers) are relatively well-known, little has been written yet about the potential of pulsed radiofrequency interactions with other fibers. The proposed algorithm, specifically elaborated, investigates the effect of this technique on neuromuscular fatigue, through a surface electromyographic study of the femoral nerve of a patient with residual pain after knee arthroplasty surgery, before and after the treatment. This work yields a preliminary result that is encouraging for subsequent large-scale studies.

Pulsed Radiofrequency Therapy at Different Voltages on Dorsal Root Ganglia Using Multifunctional Catheter to Treat Low Back Pain: A Comparative Retrospective Study

BACKGROUND

Applying pulsed radiofrequency (PRF) to the dorsal root ganglion (DRG) is an electrical neuromodulation technique, a valid complementary therapeutic treatment for failed back surgery syndrome (FBBS). Peridurolysis, when applied to vertebral canal adhesions, can be performed with dedicated catheters, providing patients with the benefits of mechanical, electrical, and pharmacological techniques.

OBJECTIVES

The aim of this study was to evaluate PRF's effects on the DRG as part of FBSS treatment at different follow-up times, comparing 2 groups of patients exposed to distinct levels of voltage (100 V vs. 45 V) from a PRF generator.

STUDY DESIGN

A retrospective observational study was performed.

SETTING

The study was conducted on a sample of patients from an Italian hospital.

METHODS

PRF's effects on the DRG as part of FBSS treatment were evaluated through the Numeric Rating Scale (NRS) and the monitoring of 155 patients' opioid consumption at 3, 6, and 9 months. A Cosman® G4 model PRF generator was used. During follow-up periods, the Friedman test was applied to detect differences in outcomes between the 2 groups of patients, who were treated with different levels of voltage.

RESULTS

The most frequent diagnosis (61.29%) was FBBS in patients at a mean age of 64 (± 11.8) years old. All patients were treated with PRF on the dorsal ganglion, with the addition of a drug mixture. Most were treated with 100 V (62%). A statistically significant decrease (P < 0.001) in the NRS score emerged both as a whole and in the 2 distinct groups. Moreover, the group of 100 V patients showed a significant (P = 0.0360) reduction in the use of opioids.

LIMITATIONS

This observational retrospective study was based on a convenience sampling that involved a limited number of patients.

CONCLUSIONS

E-field technology is the only way to generate a constant 38°/42° PRF and 100 V level throughout surgical interventions (respecting the exposure times "set" by the operator). The patient will not feel any pain or electric current because the generated milliamperes will be greatly reduced.

Feasibility of a promising pulsed electrostimulator for rapid motor recovery of foot drop

Purpose

Foot drop still occurs in clinical practice, including in our case. Treatments for foot drop vary based on its etiology and severity of symptoms. Hence, in intractable foot drop cases, an invasive surgical intervention is needed. Here, we introduce a special noninvasive technique to treat our patient's foot drop. In this approach, we applied STIMPOD NMS460 neuromuscular stimulator device (STIMPOD NMS460), which is a low-frequency (10 Hz or less) transcutaneous electrical nerve stimulation (TENS) device with a pulsed radiofrequency (PRF) component. We are eager to know how effective the device is in treating foot drop, and we compared it with two kinds of surgical interventions.

Materials and methods

The device settings are 5 Hz in frequency and 30mA in current amplitude. The device was applied on her left side at the L4 and L5 regions and at the fibular head. Each therapy session consists of individual 15-min treatments on these two body areas, and it only takes a total of 30 minutes. We recorded the change in ankle dorsiflexion degrees and muscle strength of our patient.

Results and Conclusions

To our surprise, our patient's actual treatment status through STIMPOD NMS460 showed more effective recovery and no specific side effects than surgical interventions in similar conditions. Besides, after a three-month intervention, her affected ankle dorsiflexion recovered to almost her usual status. The reason why this device has such an effect may be that it has the benefits of TENS and PRF. Besides, some studies have revealed the nerve-repair effect of TENS and PRF. In conclusion, we believe that this device is fairly promising and may be qualified to be used in other patients with foot drop.

Pulsed Radiofrequency Neuromodulation for Post-Stroke Shoulder Pain in Patients with Hemorrhagic Stroke

Objective

Post-stroke shoulder pain (PSSP) is a common complication that limits the range of motion (ROM) of the shoulder, the patient's rehabilitation and in turn, affects the patients' quality of life (QOL). Several treatment modalities such as sling, positioning, strapping, functional electrical stimulation (FES), and nerve block have been suggested in literatures, however none of the treatments had long-term effects for PSSP. In this study, the authors evaluated clinical efficacy of pulsed radiofrequency (PRF) neuromodulation on the suprascapular nerve for PSSP, and suggested it as a potential treatment with long-term effect.

Methods

This retrospective case series was conducted at a single center, a private practice institution. From 2013 to 2021, 13 patients with PSSP underwent PRF neuromodulation of the suprascapular nerve. The primary outcome measure was the visual analog scale (VAS) score. The secondary outcome measurements included the shoulder ROM, disability assessment scale (DAS), modified Ashworth scale (mAS), modified Rankin scale (mRS), and EuroQol-5 dimension-3L questionnaire (EQ-5D-3L) scores. These parameters were evaluated before PRF modulation, immediately after PRF modulation, and every three months until the final follow-up visit.

Results

Six men and seven women were enrolled, and all patients were followed-up for a minimum of 12 months. The mean VAS score was 7.07 points before PRF neuromodulation and 2.38 points immediately post-procedure. Shoulder ROM for abduction and flexion, DAS for pain, mRS, and EQ-5D-3L demonstrated marked improvement. No complications were reported.

Conclusion

PRF neuromodulation of the suprascapular nerve is an effective modality in patients with PSSP, and has long-term effect of pain relief, improvement of QOL.

Percutaneous Stylomastoid Foramen Pulsed Radiofrequency Combined with Steroid Injection for Treatment of Intractable Facial Paralysis After Herpes Zoster

INTRODUCTION

We investigated the safety and efficacy of percutaneous facial nerve pulsed radiofrequency combined with drug injection for treatment of intractable facial paralysis of herpes zoster. The authors provide a detailed description of percutaneous facial nerve pulsed radiofrequency combined with steroid injection for treatment of intractable facial paralysis after herpes zoster, and they examine its clinical efficacy. This is the first time in the literature to our knowledge that this procedure has been applied in facial paralysis after herpes zoster.

METHODS

A total of 43 patients with a history of facial paralysis after herpes zoster for > 1 month were enrolled in this retrospective study. The patients were subjected to percutaneous stylomastoid foramen pulsed radiofrequency of the facial nerve under computed tomography (CT) guidance combined with drug injection. The House-Brackmann grades and NRS (Numerical Rating Scale) data collection were performed at different time points (preoperatively, 1 day post-procedure, and 2, 4, and 12 weeks postoperatively). The occurrence of complications was also assessed.

RESULTS

The 43 participants successfully completed the CT-guided percutaneous stylomastoid foramen pulsed radiofrequency of the facial nerve combined with drug injection. Both approaches [posterior approach of the ear (7 cases) and anterior approach of the ear (36 cases)] were efficacious and safe. The House-Brackmann grades (I, II, III, IV, V, VI) were 4 (3-4), 2 (2-3), 1 (1-2), and 1 (0-2) at different operation times (T0, T1, T2, T3, T4); patients felt significant recovery at T1 after operation and had gradually recovered at each time point but had no significant recovery after T3. The NRS scores at different operation times were 2.690 ± 2.213, 0.700 ± 0.939, 0.580 ± 1.006, 0.440 ± 0.908, and 0.260 ± 0.759, respectively. Differences in NRS scores between T0 and T1/2/3/4 were significant while differences between T1 and T2/3/4 were not significant. Six patients developed mild numbness, nine patients exhibited muscle tension, while one patient exhibited facial stiffness. During surgery, there was no intravascular injection of drugs, no nerve injury was reported, and there was no local anesthetic poisoning or spinal anesthesia.

CONCLUSIONS

Percutaneous stylomastoid foramen pulsed radiofrequency combined with drug injection of the facial nerve for treatment of intractable facial paralysis after herpes zoster is a minimally invasive technique with high rates of success, safety, and effective outcomes. It is a potential therapeutic option for cases of facial paralysis of herpes zoster with a > 1 month history even for those with severe facial paralysis and whose treatment has failed after oral medication and physiotherapy.

Pulsed radiofrequency on DRG inhibits hippocampal neuroinflammation by regulating spinal GRK2/p38 expression and enhances spinal autophagy to reduce pain and depression in male rats with spared nerve injury

Evidence indicates that microglial G protein-coupled receptor kinase 2 (GRK2) is a key regulator of the transition from acute to chronic pain mediated by microglial products via the p38 mitogen-activated protein kinase (MAPK) pathway in the spinal cord dorsal horn (SCDH). Increasing studies have shown that autophagic dysfunction in the SCDH and neuroinflammation in the hippocampus underlie NeP. However, whether GRK2/p38MAPK and autophagic flux in the SCDH and hippocampal neuroinflammation are involved in NeP and depression comorbidity has not been determined. Here, we explored the effects of high-voltage pulsed radiofrequency (PRF) (85 V-PRF; HV-PRF) to the dorsal root ganglion (DRG) on pain phenotypes in Wistar male rats with spared nerve injury (SNI) and the underlying mechanisms. The exacerbation of pain phenotypes was markedly relieved by PRF-DRG. The SNI-induced reduction in GRK2 expression, elevation of p-p38 MAPK levels in the SCDH, and increase in IL-1β and TNF-α levels in the hippocampus were reversed by PRF, which was accompanied by an increase in autophagic flux in spinal microglia. The beneficial effect of 85 V-PRF was superior to that of 45 V-PRF. In addition, the improvements elicited by 85 V-PRF were reversed by intrathecal injection of GRK2 antisense oligonucleotide, and these changes were accompanied by GRK2 downregulation and p-p38 upregulation in the SCDH, increased pro-inflammatory factor levels in the hippocampus, and excessive autophagy in spinal microglia. In conclusion, our data indicate that the application of HV-PRF to the DRG could serve as an excellent therapeutic technique for regulating neuroimmunity and neuroinflammation to relieve pain phenotypes.

A new neuromodulation method in chronic migraine; non-ınvasive pulsed radiofrequency, a single-blinded, randomised, controlled trial

OBJECTIVE

Non-invasive pulsed radiofrequency (NipRF) therapy, a neuromodulation method for peripheral nerves, is a new treatment modality for pain. We aimed to show the changes in pain severity and frequency per month in chronic migraine with NipRF treatment.

METHODS

We treated patients diagnosed with chronic migraine according to the International Classification of Headache Disorders III beta diagnostic criteria. In half of the patients, we applied pulsed radiofrequency (pRF) treatment with transcutaneous electrodes to the greater occipital nerve (GON) trace. In the other half, we applied the GON block under ultrasound guidance. The Migraine Disability Assessment Scale (MIDAS) was administered to the participants, and those with scores > 2 were included in the study. Pain intensity and frequency were evaluated using the visual analog scale (VAS) and a headache diary completed before and 4 weeks after treatment.

RESULTS

When both groups were compared, the pre- and post-treatment VAS scores and headache frequencies were similar. Comparing the pre-treatment and post-treatment values within the groups, VAS scores and headache frequency decreased significantly after treatment in both groups (p < 0.001).

CONCLUSION

In this study, we observed that NipRF treatment is safe and effective for treating chronic migraine. Pain intensity and frequency decreased with NipRF treatment, similar to that in the GON block group.

CLINICAL TRIALS REGISTRATION NUMBER

NCT05499689, Date: 08/11/2022.

Efficacy of conditioned autologous serum therapy (Orthokine®) on the dorsal root ganglion in patients with chronic radiculalgia: study protocol for a prospective randomized placebo-controlled double-blind clinical trial (RADISAC trial)

BACKGROUND

Pulsed radiofrequency (PRF) treatment on the dorsal root ganglion (DRG) has been proposed as a good option for the treatment of persistent radicular pain based on its effect of neuromodulation on neuropathic pain. Autologous conditioned serum (ACS) therapy is a conservative treatment based on the patient's own blood. The aim of this manuscript is to develop a study protocol using ACS on the DRG as a target for its molecular modulation.

METHODS

We plan to conduct a randomized controlled study to compare the efficacy of PRF therapy plus ACS versus PRF therapy plus physiological saline 0.9% (PhS) on the DRG to reduce neuropathic pain in patients with persistent lower limb radiculalgia (LLR) and to contribute to the functional improvement and quality of life of these patients. Study participants will include patients who meet study the inclusion/exclusion criteria. Eligible patients will be randomized in a 1:1 ratio to one of treatment with PRF plus ACS (experimental group) or PRF plus PhS (placebo group). The study group will consist of 70 patients (35 per group) who have experienced radicular pain symptoms for ≥ 6 months' duration who have failed to respond to any therapy. Both groups will receive PRF on the DRG treatment before the injection of the sample (control or placebo). Patient assessments will occur at baseline, 1 month, 3 months, 6 months, and 12 months after therapy. The primary efficacy outcome measure is Numeric Pain Rating Scale (NPRS) responders from baseline to 12 months of follow-up using validated minimal important change (MIC) thresholds. A reduction of ≥ 2 points in NPRS is considered a clinically significant pain relief. The secondary efficacy outcome measure is the proportion of Oswestry Low Back Pain Disability Scale (ODS) responders from baseline to 12 months of follow-up in the experimental group (PRF plus ACS) versus the placebo group (PRF plus PhS). ODS responders are defined as those patients achieving the validated MIC of ≥ 10-point improvement in ODS from baseline to 12 months of follow-up as a clinically significant efficacy threshold.

DISCUSSION

This prospective, double-blind, randomized placebo-controlled study will provide level I evidence of the safety and effectiveness of ACS on neuropathic symptoms in LLR patients. TRIAL REGISTRATION {2A}{2B}: EUDRACT number: 2021-005124-38. Validation date: 13 November 2021. Protocol version {3}: This manuscript presents the 2nd protocol version.

Effectiveness of Pulsed Radiofrequency Based on the Minimum Clinically Important Differences in Lumbar Spine-Related Pain in Patients without Recent Lumbar Surgery

BACKGROUND

Pulsed radiofrequency (PRF) has been used for treatment of chronic pain in several body regions, including axial and radicular pain. However, a limited number of reports have specifically demonstrated the effectiveness of PRF for spine-related pain among nonsurgical patients. Therefore, we evaluated the effectiveness of PRF for lumbar spine-associated pain in patients without recent spine surgery, and identified the factors associated with clinically meaningful improvement in pain and quality of life.

METHODS

Records of patients who underwent PRF for lumbar spine-related pain and were followed up over 6 months between 2019 and 2022 were retrospectively reviewed. Data on patient demographics, interventional factors, and patient-reported outcomes, such as the numerical rating scale (NRS) and EuroQol Group 5 Dimension 5-Level Quality of Life (EQ-5D-5 L), were collected. Patients were divided into 2 groups (responsive and nonresponsive) based on the NRS and EQ-5D-5 L scores using the previously reported minimal clinically important difference values of the NRS and EQ-5D-5 L as cutoffs, and baseline parameters were compared to identify contributing factors.

RESULTS

Forty-three patients were included in the final analysis. The NRS and EQ-5D-5 L scores improved significantly at 3 and 6 months after PRF compared to baseline. The groups with NRS and EQ-5D-5 L improvement over the minimal clinically important difference had significantly higher baseline NRS and EQ-5D-5 L scores.

CONCLUSIONS

Our results demonstrated that PRF improved pain and patient-reported outcomes for spine-related pain for at least 6 months in our patient cohort. PRF may be a good option for treating lumbar spine-related issues, even with severe pain and/or dysfunction.

Effect of Radiofrequency on Dorsal Root Ganglion Versus Transforaminal Steroids Injection on Tumor Necrosis Factor-Alpha Level in Lumbar Radicular Pain

BACKGROUND

The mechanism of pain control with pulsed radiofrequency (PRF) is unclear.

OBJECTIVES

We aimed to compare the efficacy of combined PRF on dorsal root ganglion (DRG) with transforaminal epidural steroid injection (TFESI) vs TFESI-alone on pain improvement and serum tumor necrosis factor-alpha (TNF-a) level in lumbar disc-related radicular pain.

STUDY DESIGN

Prospective, randomized, controlled trial.

SETTING

Neurology and Pain Management clinics.

METHODS

A total of 80 patients with lumbar disc prolapse were divided into 2 groups: combined PRF on DRG with TFESI group and TFESI-alone group. The Numeric Rating Scale (NRS-11), Oswestry Disability Index (ODI), and Functional Rating Index (FRI) before intervention and at 2 weeks, 1 month, and 3 months after the intervention were observed. Serum TNF-a level was assessed pre- and post-intervention at 3 months.

RESULTS

The scores of NRS-11, ODI, and FRI showed a significant improvement at 2 weeks, 1 month, and 3 months following intervention in both combined PRF & TFESI group and TFESI-alone group (P < 0.001 in all comparisons), with no significant difference between the 2 groups. Serum TNF-a levels showed a statistically significant reduction, 3 months following intervention in the combined PRF & TFESI group (P < 0.001), but not in the TFESI-alone group (P = 0.297) (P between groups < 0.001).

LIMITATIONS

The main limitation of this study is that TNF-a level was not assessed earlier to see how long the steroids might reduce TNF-a. On the other hand, further study with extended follow-up periods is needed to confirm the long-term lowering effect of TNF-a provided by PRF.

CONCLUSIONS

Combined PRF on DRG with TFESI showed similar outcomes to TFESI-alone in relieving pain in patients with lumbar disc prolapse. However, PRF on DRG caused a significant decrease in TNF-a serum levels at 3 months.

Ocular involvement in sphenopalatin ganglion pulsed radiofrequency

Pulsed radiofrequency (PRF) treatment of the sphenopalatine ganglion is an important interventional treatment in refractory cases of trigeminal neuralgia (TN) or atypical facial pain, given the easy access to its location. Despite the fact that complications from this technique are rare and it is a fairly safe procedure, ophthalmologists should know about it due to the anatomical relations of this ganglion.

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).

A comparison of pulsed radiofrequency and radiofrequency denervation for lumbar facet joint pain

BACKGROUND

Lumbar facet joint pain is a common disorder. The main symptom is chronic lumbar pain, which can reduce quality of life. Radiofrequency has often been used to treat lumbar facet joint pain. However, the effectiveness of this technique has been controversial. This study was conducted to compare the effectiveness of pulsed radiofrequency (PRF) and radiofrequency denervation (RD) for lumbar facet joint pain.

METHODS

One hundred and forty-two patients with lumbar facet joint pain were allocated to two treatment groups: PRF group (N = 72) and RD group (N = 70). Patients enrolled in the study were assessed using a visual analogue scale (VAS), Roland-Morris questionnaire (RMQ), Oswestry disability index (ODI) and Short-Form 36 (SF-36) questionnaire before therapy, 3 months and 12 months later.

RESULTS

There were no significant differences in VAS, RMQ score, ODI score and SF-36 score at 3 months (p > 0.05). Significant differences in pain control were observed in both groups at 12 months (3.09 ± 1.72 vs. 2.37 ± 1.22, p = 0.006). There was a significant difference in RMQ score (11.58 ± 3.58 vs. 8.17 ± 2.34, p < 0.001) and ODI score (43.65 ± 11.01 vs. 35.42 ± 11.32, p < 0.001) at 12 months. The total SF-36 score was higher in the RD group than in the PRF group at 12 months (58.45 ± 6.97 vs. 69.36 ± 6.43, p < 0.001). In terms of complications, skin numbness occurred in three patients. Mild pain such as burning and pinking at the puncture site in two patients. One patient experienced a decrease in back muscle strength and back muscle fatigue. These complications disappeared in 3 weeks without any treatment. There were no serious adverse events in the PRF group.

CONCLUSION

Radiofrequency is an effective and safe treatment option for patients with lumbar facet joint pain. RD could provide good and lasting pain relief, with significant improvement in lumbar function and quality of life at long-term follow-up.

High-voltage, Long-duration Pulsed Radiofrequency to the Dorsal Root Ganglion Provides Improved Pain Relief for Herpes Zoster Neuralgia in the Subacute Stage

BACKGROUND

Postherpetic neuralgia (PHN) is pain persisting beyond 3 months from rash onset and is the most common complication of herpes zoster (HZ); it is commonly refractory to medication treatment. Available evidence indicates that high-voltage, long-duration pulsed radiofrequency (PRF) to the dorsal root ganglion (DRG) is a novel and effective treatment for this complication. Nevertheless, the effects of this intervention on refractory HZ neuralgia less than 3 months have not been evaluated.

OBJECTIVE

The objective of this study was to assess the therapeutic efficacy and safety of high-voltage, long-duration PRF to the DRG for patients with subacute HZ neuralgia compared with that of patients with PHN.

STUDY DESIGN

A retrospective comparative research.

SETTING

Hospital department in China.

METHODS

Sixty-four patients with HZ neuralgia in different stages receiving high-voltage, long-duration PRF to the DRG were included. According to the days from zoster onset to PRF implementation, they were divided into the subacute (one to 3 months) or PHN group (more than 3 months). The therapeutic effect was evaluated by pain relief using the Numeric Rating Scale at one day, one week, one month, 3 months, and 6 months post-PRF. The five-point Likert scale measured patient satisfaction. Post-PRF side effects were also recorded to determine the safety of the intervention.

RESULTS

The intervention significantly reduced pain in all patients, but pain relief at one month, 3 months, and 6 months post-PRF was better in the subacute group than in the PHN group. Furthermore, the success rate of PRF was significantly increased in the subacute group compared with the PHN group (81.3% vs 56.3%, P = 0.031). There was no significant difference in patient satisfaction at 6 months between groups.

LIMITATIONS

This is a single-center retrospective study with a small sample size.

CONCLUSIONS

High-voltage, long-duration PRF to the DRG is effective and safe for HZ neuralgia in different stages, and can provide an improved pain relief for HZ neuralgia in the subacute stage.

Ultrasound-guided pulsed radiofrequency of cervical nerve root for cervical radicular pain: a prospective randomized controlled trial

BACKGROUND CONTEXT

Pulsed radiofrequency (PRF) on cervical dorsal root ganglion (DRG) for pain management in cervical radicular pain is mainly performed via a transforaminal approach under fluoroscopic guidance. Ultrasound-guidance periradicular cervical nerve root intervention raises concern about the neuromodulatory effect. This study aims to evaluate the effectiveness and duration of pain relief between PRF treatment and steroid injection on the cervical nerve roots.

PURPOSE

To evaluate the efficacy of pulsed radiofrequency for cervical radicular pain.

STUDY DESIGN

A prospective, double-blinded, randomized controlled clinical trial PATIENT SAMPLE: Patients who underwent ultrasound-guided periradicular cervical nerve root PRF or steroid injection from January 2020 to May 2021 at King Chulalongkorn Memorial Hospital (KCMH), Bangkok, Thailand.

OUTCOME MEASURES

The primary outcome was the pain score at 3 months postprocedure. The secondary outcomes were the duration of pain relief of at least 50%, pain scores at other time points after pain intervention, the amount of rescue pain medications, procedural time, and complications.

METHOD

Forty-two patients who presented with chronic cervical radicular pain were prospectively randomized into the PRF and steroid groups. Patients in the PRF group received PRF treatment at 42^°C for 4 minutes, followed by the injection of 2% lidocaine 1.5 mL and dexamethasone 10 mg to the targeted cervical nerve root. The steroid group received the same injectate. Patients and pain assessors were blinded. The numerical rating scale (NRS) and the Neck Disability Index (NDI) questionnaires were used for pain intensity and neck functional assessment before and after the procedure. Pain reduction was recorded up to a 9-month follow-up.

RESULTS

Data analysis was obtained from 20 and 21 patients receiving PRF and steroid treatment, respectively. At 3-month postprocedure, there were 70% of patients in the PRF group reported 50% pain reduction compared with 23.8% of patients in the steroid group (p<.01). Moreover, patients in the PRF group had significantly less pain (NRS 2.8±2.7) compared with patients in the steroid group (NRS 5.5±2.6) (p=.01). The neck disability index demonstrated significant improvement at 3 and 6 months (p<.01) after PRF treatment compared with steroid injection alone. The duration, in which pain relief was at least 50%, was significantly longer in patients who received PRF treatment (6.0±4.1 months) compared with those in the steroid group (2.3±2.1 months) (p<.01).

CONCLUSION

Ultrasound-guided periradicular cervical nerve root PRF exhibited a neuromodulatory effect and was considered effective for patients with cervical radicular pain. It provided a longer duration of pain relief and improvement of neck function for up to 6 months.

Pulsed Radiofrequency for the Treatment of Trigeminal Neuralgia

PURPOSE OF REVIEW

Trigeminal neuralgia is a sudden, unilateral, stabbing pain in the distribution of one or more branches of the fifth cranial nerve, with an overall prevalence ranging between 0.03 and 0.3%. While conservative treatments may offer temporary relief, many patients experience chronic headaches associated with their neuralgia. Invasive treatments are available for patients with intractable neuralgia; however, they may cause permanent tissue damage and often do not provide relief. This article examines pulsed radiofrequency (PRF) ablation (RFA) of the trigeminal nerve as a minimally invasive procedure that offers a promising alternative to invasive procedures for relief of trigeminal neuralgia while minimizing tissue damage.

RECENT FINDINGS

Efficacy of PRF and RFA in treating trigeminal neuralgia has been studied before, but literature lacks large size studies. The results of this retrospective study indicate that PRF can be used as a safe and effective treatment for patients suffering from trigeminal neuralgia that is refractory to conservative measures.

Effect of Repeated High-voltage Long-duration Pulsed Radiofrequency on Herpetic Neuralgia

BACKGROUND

Pulsed radiofrequency (PRF) is a commonly used, minimally invasive method to treat herpes zoster neuralgia, but the intensity of standard voltage PRF is limited, resulting in patients not getting a lasting therapeutic effect. The therapeutic effect of repeated high-voltage long-duration PRF on acute herpes zoster neuralgia has not been studied.

OBJECTIVE

How to effectively reduce the incidence of postherpetic neuralgia is a serious challenge for clinicians. The purpose of this study was to investigate the clinical efficacy of repeated high-voltage long-duration pulsed radiofrequency therapy for patients with acute herpetic neuralgia and its preventive effect on postherpetic neuralgia.

STUDY DESIGN

This is a retrospective study.

SETTING

The study was carried out in the Pain Department of the affiliated Hospital of Jiaxing College in Jiaxing, China.

METHODS

Eighty-one patients with acute herpetic neuralgia, who underwent minimally invasive treatment in the Pain Department of Jiaxing First Hospital from January 2020 through December 2020 were retrospectively analyzed. Patients were divided into 3 groups (n = 27 each group) according to treatment method: standard voltage PRF (group S); high-voltage long-duration PRF (group H), and repeated high-voltage long-duration PRF (group R). Pain was assessed according to Numeric Rating Scale (NRS-11) scores and analgesic drug doses were recorded. Blood galectin-3 (gal-3) and interleukin (IL)-6 levels among the 3 groups were compared before treatment and at one, 2, and 4 weeks posttreatment. The incidence of postherpetic neuralgia (PHN) and complications in the 3 groups were recorded.

RESULTS

Pain intensity, blood levels of gal-3 and IL-6, and the dose of orally administered gabapentin capsules and morphine were reduced in all patients after treatment. Compared to group S, patients in group R exhibited lower NRS-11 scores, blood levels of gal-3 and IL-6, and dosages of oral gabapentin capsules after treatment. The incidence of PHN was significantly lower at weeks 4, 8, and 12. No adverse reactions occurred in the 3 groups posttreatment.

LIMITATIONS

Our small sample size is a limitation; we look forward to increasing the sample size in follow-up studies and exploring relevant conclusions in randomized controlled trials.

CONCLUSION

Repeated high-voltage long-duration PRF therapy was an effective treatment for acute herpetic neuralgia and may prevent the occurrence of PHN.

The effect of pulsed radiofrequency application on nerve healing after sciatic nerve anastomosis in rats

The Effect of Pulsed Radiofrequency Application on Nerve Healing After Sciatic Nerve Anastomosis in Rats. In this study, we aimed to evaluate the histomorphological and functional effect of Pulsed Radiofrequency (PRF) application on regeneration after experimental nerve damage in rats. Forty Sprague-Dawley male rats were used in the study. Sciatic nerve incision was applied to all rats and then anastomosis was performed. Twenty rats were separated as the control group, and the remaining 20 rats underwent PRF every day at 42oC, for 120 seconds. The groups were divided into two further subgroups to be sacrificed on the 15th and 30th days. Tissue samples were obtained from all groups at 24 hours and 72 hours after the injury. Sections of sciatic nerve samples were stained with hematoxylin-eosin for light microscopic investigation and prepared for evaluation of ultrastructural changes with transmission electron microscopy. In the evaluation of axon numbers and diameters were seen that the 30th-day RF group had an increase compared to the control group. In the electron microscopic examination, it was observed that myelinated and unmyelinated nerve fiber sheaths had borders that are more regular in the RF group, the nucleus structures of schwann cells were better preserved, mitochondrial damage was less, and the extensions of fibroblast and collagen fibers were smoother than the control group. The findings suggested that PRF application has a positive contribution histologically on nerve healing in the early period after full-layer incision nerve injury anastomosis surgery.

The Therapeutic Efficacy of Pulsed Radiofrequency Alone Versus a Dexamethasone and Pulsed Radiofrequency Combination in Patients With Trigeminal Postherpetic Neuralgia: A Double-blind, Randomized Controlled Trial

BACKGROUND

Pulsed radiofrequency (PRF) of the Gasserian ganglion is a common surgical intervention used to treat trigeminal postherpetic neuralgia (PHN). Dexamethasone has been reported to possess anti-inflammatory effects and potential analgesic benefits.

OBJECTIVES

The primary objective of our study was to compare the therapeutic efficacies of PRF alone versus a combination of PRF and dexamethasone for trigeminal PHN.

STUDY DESIGN

A prospective, double-blind, randomized controlled trial.

SETTING

Department of Pain Management, Wuhan First Hospital.

METHODS

A total of 103 patients diagnosed with trigeminal PHN were randomly assigned into 2 groups (the PRF group and PRF plus dexamethasone [PRF+D] group). Digital subtraction angiography-guided puncture of the Gasserian ganglion was performed. All patients received PRF of the Gasserian ganglion first, and then a local injection was administered into the Gasserian ganglion. Patients in the PRF+D group received PRF therapy and one mL of 5 mg dexamethasone in the Gasserian ganglion, while patients in the PRF group received PRF therapy and one mL of normal saline in the Gasserian ganglion. The primary outcome was pain intensity, measured by the visual analog scale (VAS). The secondary outcome was quality of life, assessed by the Short Form-36 questionnaire (SF-36). The dosage of pregabalin administered was recorded to assess treatment effectiveness.

RESULTS

Compared with the PRF group in this study, the PRF+D group showed more promising outcome results in pain relief as measured by the VAS; quality of life enhancement, as measured by the SF-36; and a reduced requirement for antiepileptic drugs (P < 0.01).

LIMITATIONS

Single center study, relatively small number of patients.

CONCLUSIONS

The therapeutic efficacy of PRF combined with a dexamethasone injection into the Gasserian ganglion was superior to that of PRF{and saline injection} alone of the Gasserian ganglion for trigeminal PHN.

Efficacy and Safety of Using Noninsulated Microneedle Radiofrequency Alone Versus in Combination with Polynucleotides for the Treatment of Melasma: A Pilot Study

Introduction

This split-face, double-blind, randomized controlled study investigated the efficacy and safety of using a microneedling radiofrequency (RF) device with polynucleotides (PN) versus RF alone for the treatment of melasma.

Methods

Thirty adult participants with melasma (Fitzpatrick skin types III–V) received three treatments with an invasive, bipolar, pulsed-type microneedling RF device on both sides of the face. The treatment sessions occurred once every 2 weeks. The hemifaces of each participant were designated for treatment and control with PN and normal saline solution (NSS), applied after treatment with RF. Measurements were made of melanin index (MI), erythema index (EI), skin roughness (by the Antera 3D system), modified melasma area severity index (mMASI) for each hemiface, and patients’ self-assessed improvement. These occurred at baseline and again following the final treatment (2 weeks and 1, 2, 3, and 6 months after). Mean values were obtained for MI, EI, skin roughness, and mMASI. A generalized estimating equation (GEE) was used to compare the obtained values for the outcome measures across all assessment points.

Results

All patients were women (mean age, 43.2 ± 7.0 years). Mixed melasma predominated (61.5%; n = 16), and the mean duration of melasma was 8.9 ± 6.5 years. Twenty-six participants were followed up to the 6-month assessment point. Significant improvements were observed from baseline in MI, skin roughness, and mMASI scores for both the PN and control sides at 6 months, with no statistically significant differences between sides. Patients’ self-assessed improvement scores also showed a positive trend. Melasma recurrence was observed in three patients at 2, 3, and 4 months after the last treatment session (10% recurrence rate).

Conclusions

The combination of an invasive, bipolar, pulsed-type microneedling RF with PN is not superior compared with microneedling RF alone in the treatment of melasma. Microneedling RF may be considered as safe and efficacious for the improvement of skin roughness, and as an adjunctive treatment option for melasma.

Clinical Trial Registration

This study was registered on ClinicalTrials.gov and assigned NCT number TCTR20210804002.

Pulsed Radiofrequency of the Vagal Nerve for Tinnitus -A Case-Study

TINNITUS BACKGROUND

Vagal nerve stimulation is a promising therapy for tinnitus. Pulsed radiofrequency is a minimally invasive neuromodulator technique that could be applied repeatedly without damage to neural tissue. In this case-study we document the use of pulsed radiofrequency of the vagal nerve as a successful therapy without harm for patients with tinnitus.

METHODS

A 22-gauge, 60 mm-long needle with a 5 mm active tip was placed percutaneously at the inner side of the tragus. The auricular branch of the vagal nerve was subjected to pulsed radiofrequency at 42 V, 2 Hz, and 10 milliseconds for 10 minutes.

RESULTS

Pulsed radiofrequency of the vagal nerve can reduce tinnitus and improve hearing in a patient with severe tinnitus and hearing loss. The intensity of the tinnitus was reduced to 5% of the original intensity at the left side and to 20% at the right side. An improved hearing of 20 to 30 dB from 250 Hz to 8 kHz in the left ear and from 250 Hz to 2 kHz in the right ear was objectivated in the audiogram.

CONCLUSIONS

This case-study document that PRF of the vagal nerve can reduce tinnitus and improve hearing in a patient with severe tinnitus and hearing loss. However, further research of PRF of the vagal nerve in tinnitus patients is needed.

Comparison of ultrasound-guided pulsed radiofrequency versus steroid injection in the treatment of carpal tunnel syndrome

BACKGROUND

Carpal tunnel syndrome (CTS) is the most widespread form of nerve entrapment neuropathy results from increase compression pressure of the median nerve at the wrist under the transverse carpal ligament.

AIMS

To compare ultrasound (US)-guided median nerve steroid injection and pulsed radiofrequency (PRF) on pain intensity, functional status, and patient satisfaction in the treatment of CTS.

METHODS

A total of 90 hands of 59 patients who underwent steroid injection at the level of proximal carpal tunnel or PRF for CTS were retrospectively analyzed. Demographic and clinical characteristics of the patients were recorded. The pain severity was assessed using the Numerical Rating Scale (NRS), and the functional status and clinical outcomes were assessed using the Boston Carpal Tunnel Questionnaire (BCTQ) before the procedure and at Week 1, Month 1, and Month 3 after the procedure. Time to pain relief was evaluated at week 1. Patient satisfaction was evaluated at Month 3.

RESULTS

There was no significant difference in the NRS and BCTQ scores between the two treatment methods (p > 0.05 for both). In addition, a significant decrease in the NRS and BCTQ scores were detected at all follow-ups compared to baseline in treatment groups (p < 0.001). The mean time to pain relief was significantly shorter in the PRF group (p < 0.001). Patient satisfaction was similar at Month 3 between the treatment methods (p > 0.05).

CONCLUSIONS

Our study results suggest that both US-guided steroid injection to the median nerve and PRF are effective and safe methods in the short-term in the treatment of CTS.

Pulsed Radiofrequency of Stellate Ganglion for Neuropathic Pain Associated with Recurrent Pleural Leiomyosarcoma - A Case Report

Pleural leiomyosarcomas are rare soft-tissue sarcomas. Neuropathic pain associated with such tumours can be quite debilitating. We present the case of a 62-year-old woman with chronic neuropathic pain refractory to pharmacologic interventions in association with recurrent pleural leiomyosarcoma. Pulsed radio-frequency of the stellate ganglion was performed after due consideration and planning as a palliative measure to provide pain relief. The patient was discharged the same day with pain score 0/10 and followed up for 3 years. The unique features of this case report are: (1) Different approach of the treatment modality and (2) longer follow-up.

Review of Radiofrequency Ablation for Peripheral Nerves

PURPOSE OF REVIEW

Radiofrequency ablation (RFA) has become an increasingly widespread treatment tool for various chronic pain syndromes within the last two decades with the majority of publications on the topic coming after 2006. Not only are clinicians using RFA to treat more peripheral nerve pain syndromes but the technology itself is evolving quickly to the point that it is nearly impossible to stay abreast on the complexity of such a diversely utilized instrument. This review summarizes studies that focus on the use of RFA for peripheral nerve neurotomy and anatomical studies regarding RFA published between 2015 and 2020.

RECENT FINDINGS

Topics in this review include anatomical regions or nerves of the body published since 2015. Significant findings are summarized in each section. Peripheral nerve RFA is rapidly changing. Many studies have been performed over the last 5 years showing the usefulness of RFA.

Comparison of the effectiveness of pulsed radiofrequency of the suprascapular nerve and intra-articular corticosteroid injection for hemiplegic shoulder pain management

Many patients complain of hemiplegic shoulder pain following stroke. Here, the effectiveness of pulsed radiofrequency stimulation of the suprascapular nerve is compared with intra-articular corticosteroid injection for chronic hemiplegic shoulder pain following stroke. This single-center, prospective, randomized controlled study included 20 patients with hemiplegic shoulder pain after stroke, randomly assigned to the pulsed radiofrequency and intra-articular corticosteroid injection treatment groups (n = 10 in each). Hemiplegic shoulder pain severity was measured by numeric rating scale and passive shoulder range motion was assessed at baseline and one and two months after each procedure. Compared to the baseline numeric rating scale scores, post-treatment scores decreased significantly in both groups (p < 0.001). However, score reduction through time was significantly greater for intra-articular corticosteroid injection for pulsed radiofrequency (p < 0.001). Similarly, a significant post-treatment increase was observed in almost all range of motion measurements in both groups (pulsed radiofrequency group: flexion, p = 0.015; abduction, p = 0.014; external rotation, p = 0.038; internal rotation, p = 0.063; intra-articular corticosteroid injection group: all range of motion, p < 0.001). Moreover, the measurements for all ranges of motion in the intra-articular corticosteroid injection group were significantly higher than those in the pulsed radiofrequency group (p < 0.001). Thus, intra-articular corticosteroid injection appears more effective than pulsed radiofrequency for control of hemiplegic shoulder pain, whereas, pulsed radiofrequency of the suprascapular nerve has minimal effect. However, in patients at risk for developing complications following corticosteroid injections, pulsed radiofrequency of the suprascapular nerve may be an option in management of hemiplegic shoulder pain.

Effects of thoracic sympathetic stimulation on palmar perfusion: a preliminary study in pigs

OBJECTIVE

Ablation of the upper thoracic sympathetic ganglia that innervates the hands is the most effective and permanent cure of palmar hyperhidrosis. However, this type of sympathectomy causes irreversible neural damage and may result in severe compensatory hyperhidrosis. This experiment is designed to confirm the hypothesis, in which the stimulation of T2 sympathetic chain leads to increased palmar microcirculation, and thus results in treating hyperhidrosis.

METHODS

In this study, we used electric stimulation to induce reversible blockade of the sympathetic ganglion in pigs and investigated its effect on palmar perfusion. An electrode was inserted to the T2 sympathetic ganglion of the pig through three different approaches: open dorsal, thoracoscopic, and fluoroscopy-guided approaches. Electric stimulation was delivered through the electrode using clinically available pulse generators. Palmar microcirculation was evaluated by laser speckle contrast imaging.

RESULTS

The T2 sympathetic ganglion of the pig was successfully accessed by all the three approaches, as confirmed by changes in palmar microcirculation during electric stimulation. Similar effects were not observed when the electrode was placed on the T4 sympathetic ganglion or off the sympathetic trunk.

CONCLUSION

We established a large animal model to verify the effect of thoracic sympathetic stimulation. Electric stimulation can be used for sympathetic blockade, as confirmed by increased blood perfusion of the palm. Our work suggests that sympathetic stimulation is a potential solution for palmar hyperhidrosis.

Efficacy of Pulsed Radiofrequency or Short-Term Spinal Cord Stimulation for Acute/Subacute Zoster-Related Pain: A Randomized, Double-Blinded, Controlled Trial

BACKGROUND

Postherpetic neuralgia (PHN) is the final stage of varicella zoster infection and a severe refractory neuropathic pain. Hence preventing transition of herpes zoster-related pain to PHN is a very important therapeutic principle for patients at an early stage, especially for older patients.Both pulsed radiofrequency (PRF) and short-term spinal cord stimulation (stSCS) have been proven to be effective to relieve acute/subacute zoster-related pain. However, which treatment could achieve better analgesic effects remains unclear.

OBJECTIVES

This study aimed to investigate the therapeutic efficacy and safety of PRF and stSCS in patients with acute/subacute zoster-related pain.

STUDY DESIGN

Prospective, randomized, double-blinded study.

SETTING

Department of Pain Medicine, the First Affiliated Hospital of China Medical University.

METHODS

Ninety-six patients with acute/subacute zoster-related pain were equally randomized into 2 groups: PRF group and stSCS group. Patients in the different groups were treated with high-voltage, long-duration PRF or stSCS. The therapeutic effects were evaluated using a Numeric Rating Scale (NRS-11) and the 36-Item Short Form Health Survey (SF-36) at different time points. The average dose of pregabalin (mg/d) administrated at different time points was also recorded.

RESULTS

The posttreatment NRS-11 scores in the 2 groups were significantly lower compared with baseline (P < 0.001). The NRS-11 scores in the stSCS group were significantly lower than those in the PRF group at 30 and 180 days after treatments (P < 0.05). The SF-36 scores of general health, social function, role-emotional, mental health, bodily pain, physical function, physical role, and vitality could be significantly improved at each time point after treatments in the 2 groups. Some SF-36 scores could be significantly improved at some time points in the stSCS group compared with the PRF group. The rescue drug (pregabalin) dosages were lower in the stSCS group than those in the PRF group at days 90 and 180 after treatments. There was no bleeding at the puncture site, infection, postoperative paresthesia, nerve injury, or any other serious adverse effects in either group.

LIMITATIONS

Single-center study, relatively small number of patients.

CONCLUSIONS

PRF and stSCS are both effective and safe therapeutic alternatives for patients with acute/subacute zoster-related pain, however, stSCS could achieve more pain relief and improvement of life quality compared with PRF.

Expert consensus of Chinese Association for the Study of Pain on the radiofrequency therapy technology in the Department of Pain

On the basis of continuous improvement in recent years, radiofrequency therapy technology has been widely developed, and has become an effective method for the treatment of various intractable pain. Radiofrequency therapy is a technique that uses special equipment and puncture needles to output ultra-high frequency radio waves and accurately act on local tissues. In order to standardize the application of radiofrequency technology in the treatment of painful diseases, Chinese Association for the Study of Pain (CASP) has developed a consensus proposed by many domestic experts and scholars.

Clinical efficacy of ultrasound-guided pulsed radiofrequency combined with ganglion impar block for treatment of perineal pain

BACKGROUND

Ganglion impar block alone or pulsed radiofrequency alone are effective options for treating perineal pain. However, ganglion impar block combined with pulsed radiofrequency (GIB-PRF) for treating perineal pain is rare and the puncture is usually performed with X-ray or computed tomography guidance.

AIM

To evaluate the safety and clinical efficacy of real-time ultrasound-guided GIB-PRF in treating perineal pain.

METHODS

Thirty patients with perineal pain were included and were treated by GIB-PRF guided by real-time ultrasound imaging between January 2015 and December 2016. Complications were recorded to observe the safety of the ultrasound-guided GIB-PRF procedure, and visual analogue scale (VAS) scores at 24 h before and after treatment and 1, 3, and 6 mo later were analyzed to evaluate clinical efficacy.

RESULTS

Ultrasound-guided GIB-PRF was performed successfully in all patients, and no complications occurred. Compared with pretreatment scores, the VAS scores were significantly lower (P < 0.05) at the four time points after treatment. The VAS scores at 1 and 3 mo were slightly lower than those at 24 h (P > 0.05) and were significantly lower at 6 mo after treatment (P < 0.05). There was a tendency toward lower VAS scores at 6 mo after treatment compared with those at 1 and 3 mo (P > 0.05).

CONCLUSION

Ultrasound-guided GIB-PRF was a safe and effective way to treat perineal pain. The 6-mo short-term clinical efficacy was favorable, but the long-term outcomes need future study.

Changes in the gene expression in mouse astrocytes induced by pulsed radiofrequency: A preliminary study

Glial cells, both astrocytes and microglia, play important roles in the induction and maintenance of neuroinflammation resulting in neuropathic pain. Pulsed radiofrequency (PRF) is applied to various nerves for the treatment of pain, although the molecular mechanism underlying its effects is still unclear. We herein investigated the genomic effects of PRF on a mouse cultured astrocyte cell line. PRF was applied to the cultured astrocytes in 20-msec pulses of 480 kHz every 500 msec, delivered at the rate of 2 Hz, for 30 min. PRF increased the expression of 2,431 genes and decreased that of 209 genes. Among these genes, 435 genes were upregulated >10-fold and 89 genes >30-fold, while no genes showed a 10-fold decrease in expression. A gene ontology analysis using the list of >10-fold upregulated genes showed that PRF treatment activated immune responses. A pathway analysis using the Kyoto Encyclopedia of Gene and Genomes with the same list detected seven pathways related to neuropathic pain. These findings suggest that PRF improves neuropathic pain via neuroimmunomodulation.

High-Voltage Intraarticular Pulsed Radiofrequency for Chronic Knee Pain Treatment: A Single-Center Retrospective Study

BACKGROUND

Intraarticular pulsed radiofrequency (IAPRF) for the treatment of painful knee osteoarthritis (KOA) is a less invasive treatment method. It has fewer adverse effects and can quickly reduce KOA-related pain and improve knee joint dysfunction.

OBJECTIVES

We compared the effectiveness of high- and low-voltage IAPRF for the treatment of chronic knee pain.

STUDY DESIGN

Retrospective comparative study design.

SETTING

This study took place at Shengjing Hospital of China Medical University.

METHODS

A total of 57 patients with KOA who were hospitalized between July 2018 and July 2019 were randomly allocated into the high-voltage (n = 29) and low-voltage (n = 28) IAPRF groups. IAPRF was performed under the guidance of computed tomography (CT). Numeric Rating Scale (NRS-11), Oxford Knee Score (OKS), degree of pain relief, global perceived effect, and side effects at baseline and 1 week, 2 weeks, 1 month, 3 months, and 6 months after the procedure were recorded and analyzed.

RESULTS

NRS-11 scores decreased significantly in both groups after the procedure, but gradually increased after the 6-month follow-up period. There was a significant difference in NRS-11 scores between the 2 groups at all follow-up periods postprocedure. OKS were similar between the 2 groups. Patients with pain relief rate 50% or greater at 1, 3, and 6 months after the procedure accounted for 72.41%, 72.41%, and 55.17% in the high-voltage group, and 46.43%, 46.43%, and 28.57% in the low-voltage group, respectively. The difference between the 2 groups was statistically significant. No significant adverse reactions were observed in the 2 groups, however, patient satisfaction in the high-voltage group was significantly higher compared with patients in the low-voltage group.

LIMITATIONS

This study was a single-center retrospective study with a relatively small sample cohort and short follow-up period.

CONCLUSIONS

CT-guided high-voltage IAPRF is more beneficial in reducing knee pain and improving knee function compared with low-voltage IAPRF. In addition, patients who received high-voltage IAPRF were more satisfied with their treatment.

Pulsed Radiofrequency for Lumbar Facet Joint Pain: A Viable Therapeutic Option? A Retrospective Observational Study

Introduction

Low back pain (LBP) is a common problem, and facet joint pain is responsible for 15–45% of cases. Treatment is multidisciplinary, and when conservative measures are not sufficient, radiofrequency (RF) is often used. It allows the interruption of nociceptive input, producing a heat lesion in a continuous or pulsed mode.

Methods

Medical records of 60 patients who underwent pulsed RF denervation were examined. The standard procedure provided follow-up of pain intensity. Numerical rating scale (NRS) and Douleur Neuropathique en 4 Questions (DN4) were recorded before treatment, and 15 and 40 days, and 6 months after treatment. Oswestry Disability Index (ODI) and patient satisfaction were also recorded. Successful treatment was defined as more than a 50% reduction in the NRS scores at 6 months compared with pretreatment scores.

Results

Scores on the NRS and DN4 were statistically different over time (p < 0.05). Scores at 6 months were significantly decreased when compared with pretreatment scores (p < 0.05). ODI scores decreased during the follow-up period. No adverse effect was recorded and 57 patients (97%) reported successful pain relief.

Conclusions

Continuous RF is the gold standard in the management of lumbar facet joint pain. Pulsed RF is a promising technique: patients with chronic LBP who had not responded to conservative care tended to improve after pulsed RF. The procedure was well tolerated in the absence of contraindications, and reliable if the nerve endings regrew.

Behavioral Survey of Effects of Pulsed Radiofrequency on Neuropathic and Nociceptive Pain in Rats: Treatment Profile and Device Implantation

OBJECTIVES

Pulsed radiofrequency (PRF) stimulation is widely used for intractable pain; however, there is no consensus on treatment protocols and appropriate types of pain. We compared effectiveness of bipolar and unipolar PRF on neuropathic or inflammatory pains, and of targets at the dorsal root ganglion (DRG) and sciatic nerve (SN). We also examined efficacy of repetitive PRF stimulations. This preclinical study could serve as an extensive survey before human trials.

MATERIALS

Spare nerve injury (SNI)-induced neuropathic pain and complete Freund's adjuvant (CFA) injection-induced inflammatory pain were used. Behavioral responses were measured using von Frey test, acetone test, and Hargreave's test at preinjury and postinjury time points. In both models, we evaluated results of DRG stimulation with unipolar PRF (45 V) versus bipolar PRF (5 V), stimulation at DRG vs. SN, and repetitive stimulations.

RESULTS

Both unipolar and bipolar PRFs reduced SNI- or CFA-induced pain for a similar duration. In the SNI model, PRF-DRG had a stronger effect on tactile pain than PRF-SN but lower effect on cold allodynia, whereas in the CFA model PRF-DRG and PRF-SN showed similar effects. Repetitive PRF stimulation, by open technique or implantation method, produced analogous effect by each stimulus, and no evident analgesic tolerance or neurological deficit was shown.

CONCLUSIONS

PRF temporarily attenuates neuropathic and inflammatory pain. Bipolar PRF generates significant analgesia with a much lower electrical power than unipolar PRF. Meanwhile, the minor variant effects between PRF-DRG and PRF-SN may indicate distinct mechanisms. The sustained-analgesia by repetitive treatments suggests implantation technique could be a promising choice.

Characterisation of the effects of pulsed radio frequency treatment of the dorsal root ganglion on cerebrospinal fluid cellular and peptide constituents in patients with chronic radicular pain: A randomised, triple-blinded, controlled trial

INTRODUCTION

Chronic radicular neuropathic pain is a major clinical problem with a life time prevalence of more than 50%. Pulsed radiofrequency (PRF) treatment is a recognised therapy. However, the pathophysiology of chronic neuropathic pain (CNP) and the mechanism of action of PRF remains ill-defined. Improving our knowledge of the mechanisms of CNP and PRF action will enhance our ability to treat patients with this common debilitating problem more effectively. This study aims to characterise the CSF cellular and peptide constituents in patients with CNP and the effect of pulsed radiofrequency (PRF) on these constituents and reported pain.

MATERIALS AND METHODS

Prospective randomised tripled-blinded control trial of patients receiving PRF treatment versus sham for radicular pain. All patients received local anaesthetic to the appropriate dermatome to confirm diagnosis. Clinical assessment using standard clinical assessment tools and examination of CSF using flow cytometry and ELISA for cellular and peptide constituents was carried out before and 3 months after treatment.

RESULTS

Ten patients were randomised to PRF (n = 5) or Sham (n = 5) treatment. PRF resulted in a significant reduction in pain score (NRS) at 3 months (6.8 to 2.6, p < .05). PRF reduced the TNF-α concentration and CD3+ count in CSF. CD4/CD8 ratio of patients with CNP was lower than historical controls (1.4 versus 3.0-4.2). The majority of CD3+ cells in the CNP patients were activated effector memory cells (80%) versus the surveillance central memory cells (85%) seen in healthy controls.

CONCLUSIONS

PRF is superior to local anaesthetic administration for the management of radicular pain and is associated with CSF constituent modulation in vivo. Patients with CNP have lymphocyte characteristics which suggest immune activation.

Efficacy and safety of pulsed radiofrequency as a method of dorsal root ganglia stimulation for treatment of non-neuropathic pain: a systematic review

BACKGROUND

We systematically reviewed the evidence on the efficacy and safety of dorsal root ganglion (DRG) targeted pulsed radiofrequency (PRF) versus any comparator for treatment of non-neuropathic pain.

METHODS

We searched MEDLINE, CINAHL, Embase, PsycINFO, clinicaltrials.gov and WHO clinical trial register until January 8, 2019. All study designs were eligible. Two authors independently conducted literature screening. Primary outcomes were pain intensity and serious adverse events (SAEs). Secondary outcomes were any other pain-related outcome and any other safety outcome that was reported. We assessed the risk of bias using the Cochrane tool and Risk of Bias In Non-randomized Studies of Interventions (ROBINS-I). We conducted narrative evidence synthesis and assessed the conclusiveness of included studies regarding efficacy and safety.

RESULTS

We included 17 studies with 599 participants, which analyzed various pain syndromes. Two studies were randomized controlled trials; both included participants with low back pain (LBP). Non-randomized studies included patients with the following indications: LBP, postsurgical pain, pain associated with herpes zoster, cervicogenic headache, complex regional pain syndrome type 1, intractable vertebral metastatic pain, chronic scrotal and inguinal pain, occipital radiating pain in rheumatoid arthritis and chronic migraine. In these studies, the PRF was usually initiated after other treatments have failed. Eleven studies had positive conclusive statements (11/17) about efficacy; the remaining had positive inconclusive statements. Only three studies provided conclusiveness of evidence statements regarding safety - two indicated that the evidence was positive conclusive, and one positive inconclusive. The risk of bias was predominantly unclear in randomized and serious in non-randomized studies.

CONCLUSION

Poor quality and few participants characterize evidence about benefits and harms of DRG PRF in patients with non-neuropathic pain. Results from available studies should only be considered preliminary. Not all studies have reported data regarding the safety of the intervention, but those that did, indicate that the intervention is relatively safe. As the procedure is non-destructive and early results are promising, further comparative studies about PRF in non-neuropathic pain syndromes would be welcomed.

A comparison of efficacy among different radiofrequency ablation techniques for the treatment of lumbar facet joint and sacroiliac joint pain: A systematic review and meta-analysis

OBJECTIVE

To compare the efficacy of different radiofrequency techniques (thermal, pulsed, and cooled radiofrequency) for treating lumbar facet joint (LFJ) or sacroiliac joint (SIJ) pain.

PATIENTS AND METHODS

The inclusion criteria were as follows: (1) age > 18 years; (2) patients suffering from LFJ or SIJ pain; and (3) patients receiving radiofrequency treatments. Four electronic databases, including Pubmed, Embase, Cochrane Library, and ISI Web of Knowledge were systematically searched from inception until December 2019 for relevant articles. The search was conducted on 2 January 2020. When the outcomes among articles showed heterogeneity, then a random-effects model was adopted to calculate the effect size; otherwise, a fixed-effects model was adopted.

RESULTS

All the three techniques showed significant improvements in LFJ or SIJ pain for up to 12 months compared with the baseline level. However, no significant differences among the three techniques were observed at any follow-up visits except for possibly a trend for variance in efficacy. For treating LFJ pain, cooled radiofrequency was the most effective, followed by thermal radiofrequency and then pulsed radiofrequency as the least respectively for the follow-up visit at 6 months. No serious complications were reported after receiving treatment using the three techniques.

CONCLUSION

Sequentially, cooled radiofrequency followed by thermal radiofrequency and then pulsed radiofrequency for treating LFJ pain were identified as most to least effective at the 6-month follow-up.

Dorsal root ganglion pulsed radiofrequency treatment for chronic cervical radicular pain: a retrospective review of outcomes in fifty-nine cases

Pulsed radiofrequency treatment adjacent to the cervical dorsal root ganglion is used to treat persistent cervical radicular pain that has not responded to conservative therapies. This technique has gained popularity in years for both cervical and lumbosacral radicular pain. The evidence to support its use is still evolving.

METHODS

We performed a retrospective review of outcomes in 59 patients who underwent this therapy over a 3-year period in our institution. We evaluated a reduction in pain, duration of pain relief, reduction in use of analgesics and progression to surgery.

RESULTS

Our results demonstrated 49 patients experienced some relief. Forty patients of the 59 experienced an improvement in pain of 50% or more. The mean duration of relief in this group was 37 weeks. Seven patients experienced complete resolution of their pain. In this group, the mean duration of relief was 39 weeks. Regarding the 53 patients who were taking medication for pain prior to the procedure, 37 patients reduced or discontinued their usage after the procedure.

CONCLUSION

Despite the limitations of a retrospective study, we feel our study adds to the growing evidence base that pulsed radiofrequency treatment adjacent to the cervical dorsal root ganglion has a role in the treatment of chronic cervical radicular pain.

Pulsed radiofrequency of the median nerve under ultrasound guidance for management of intractable neuropathic pain

A median nerve injury in the forearm may lead to devastating sequelae if left untreated. Even with appropriate treatments involving microsurgical techniques and postoperative care, patients may still experience lasting neuropathic pain that significantly reduces their quality of life. Pulsed radiofrequency (PRF) is widely performed to alleviate such neuropathic pain caused by trauma.

A 47-year-old man visited our pain clinic with allodynia, hyperalgesia, paresthesia, skin color changes, and atrophy in the right forearm. In the orthopedic department, the patient was treated by neurectomy of the median nerve to manage the intractable pain. However, the effect was unsatisfactory. The fourth median nerve block performed in our pain clinic after neurectomy produced good results, and ultrasound-guided PRF of the median nerve was performed.

The patient showed 80% relief of symptoms within 5 hours after the procedure. The visual analog scale score for the forearm decreased from 8/10 to 1/10. This case suggests that ultrasound-guided PRF can be a therapeutic option for the management of refractory neuropathic pain after neurectomy in patients with a median nerve injury.

Assessment of the effectiveness and safety of two radiofrequency techniques for the treatment of knee pain secondary to gonarthrosis. Prospective randomized double blind study

BACKGROUND AND OBJECTIVE

In patients with knee pain due to gonarthrosis, we have treatments that are not free of side effects.

OBJECTIVE

to evaluate the analgesic efficacy of radiofrequency (pulsed and conventional) on the saphenous nerve at the subsartorial level and the genicular nerves of the knee, by ultrasonography.

MATERIALS AND METHODS

Prospective, randomized, double-blind clinical trial. G1 (RDF1): subjects subjected to radiofrequency, G2 (PLCB): subjects subjected to placebo. A decrease ≥30% of the pain was considered clinically relevant, according to numerical rating scale and in the Western Ontario and McMaster Universities Osteoarthritis Index, global patient impression questionnaire (PGIC) and health status questionnaire (SF-12) in the evaluation at month, three months and six months after the completion of the technique.

RESULTS

28 patients (G1: 12, G2: 16), 72% women, age: 75.2±9.1 years, body mass index: 29.9±4.64. The analysis did not show a pain reduction, neither statistically significant, not clinically relevant, at one month, three, or six months with respect to the start of treatment, in the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire and numerical rating scale (rest, movement). Regarding PGIC and the SF-12 questionnaire, there were no statistically significant differences between G1 and G2 either before or after treatment.

CONCLUSIONS

The combination of two radiofrequency techniques, does not cause a reduction in the intensity of the knee pain, at month, three, or at six months after its completion. It is necessary to change the radiofrequency technique and include more variables to continue with the efficacy study.

Pulsed radiofrequency of the C2 dorsal root ganglion and epidural steroid injections for cervicogenic headache

BACKGROUND

Cervicogenic headache (CEH) is characterized by unilateral headache symptoms referred to the head from the cervical spine. Few methods have addressed long-term pain relief for CEH. This study was undertaken to evaluate pain control and quality of life after pulsed radiofrequency (PRF) for the C2 dorsal root ganglion and epidural steroid injections (ESI) for CEH.

METHODS

This was a case-control study. One hundred thirty-nine patients suffering from CEH were enrolled in this study. Of these patients, 87 CEH patients underwent PRF for the C2 dorsal root ganglion and ESI therapy, and 52 CEH patients only underwent ESI therapy. Quality of life and pain control were measured with the European Organization for Research and Treatment of Cancer (EORTC) Quality-of-Life Questionnaire (QLQ-C30) and Izbicki pain scores. Kaplan-Meier curve was used to evaluate the efficacy of the treatment in the groups.

RESULTS

Before therapy, the median of Izbicki pain score in PRF+ESI group and ESI group was 78.5 and 72.5, respectively (p = 0.574). After 2 year follow-up, significant reduction was found in the two groups (11.25 versus 40.00, p < 0.001). The two groups demonstrated an equal distribution of age and gender (p > 0.05). SF (68.52 ± 21.50 versus 50.63 ± 15.42), PF (70.61 ± 29.47 versus 47.87 ± 21.53), RF (52.04 ± 17.92 versus 38.13 ± 24.07), EF (61.17 ± 28.41 versus 43.52 ± 25.48), CF (55.36 ± 19.82 versus 46.82 ± 23.54), and QL (59.31 ± 27.44 versus 50.73 ± 21.90) were significantly higher in PRF+ESI group than in ESI group. Kaplan-Meier curve showed that the probability of treatment success in PRF+ESI group was higher than that in ESI group (median pain relief: ESI group, 4 months; PRF+ESI group, 8 months) (Log-Rank test, p < 0. 001). There was no serious side effect in this study.

CONCLUSION

The combination of PRF for the C2 dorsal root ganglion and ESI is a relatively safe therapy for CEH. This technique not only provides the sustained relief of pain symptom but improves the quality of life in patients with CEH.

Efficacy of Sphenopalatine Ganglion Radiofrequency in Refractory Chronic Cluster Headache

BACKGROUND

In the literature, there are only short series of radiofrequency of the sphenopalatine ganglion (SPG) to treat chronic refractory cluster headache (CCHr) with variable results. Furthermore, there is no consensus on which methodology to use: radiofrequency ablation (RFA) or pulsed radiofrequency (PRF).

METHODS

We conducted a prospective analysis of 37 patients with CCHr who underwent RFA or PRF of the SPG in our center between 2004 and 2015.

RESULTS

The mean age of the patients was 40 years (range, 26-59 years). PRF was performed in 24 patients, and RFA was performed in 13 patients. A total of 5 patients (13.5%) experienced complete clinical relief of both pain and parasympathetic symptoms, 21 patients (56.8%) had partial and transient relief, and 11 patients (29.7%) did not improve. There was no evidence of significant superiority of one radiofrequency modality over the other (P = 0.48). There were no complications associated with the technique. The passage of time tended to decrease the efficacy of both techniques (P < 0.001). The mean follow-up was 68.1 months (range, 15-148 months). To our knowledge, this is the series with the largest number of patients and the longest follow-up period published in the literature.

CONCLUSIONS

Radiofrequency of the SPG is a safe, fast, and partially effective method for the treatment of CCHr. Given its low rate of complications and its low economic cost, we think it should be one of the first invasive treatment options, prior to techniques with greater morbidity and mortality, such as neuromodulation.

Effect of Pulsed Radiofrequency Therapy on Chronic Refractory Atlanto-Occipital Joint Pain

OBJECTIVE

Despite several methods of conservative management, many patients with atlanto-occipital (AO) joint pain complain of persistent pain. In the current study, the authors investigated the clinical efficacy of intra-articular pulsed radiofrequency (PRF) therapy for the management of refractory chronic AO joint pain.

METHODS

Twenty patients with refractory AO joint pain were recruited, and each received intra-articular AO joint PRF stimulation. Pain reduction after PRF therapy was measured using a numerical rating scale (NRS) before and at 1 and 3 months after treatment. Successful pain relief was defined as ≥50% reduction in the NRS score compared with the pretreatment score. At 3 months after treatment, patient satisfaction levels were also examined. Patients reporting very good (score = 7) or good (score = 6) results were considered to be satisfied with the procedure.

RESULTS

The NRS scores changed significantly over time. At 1 and 3 months after PRF therapy, the NRS scores were significantly reduced compared with pretreatment scores. Sixteen of the 20 (80%) patients reported pain relief and were satisfied with treatment results 3 months after PRF. No adverse effects were reported.

CONCLUSIONS

Intra-articular PRF therapy is a beneficial treatment tool for managing refractory chronic AO joint pain.

Combined therapy of pulsed radiofrequency and nerve block in postherpetic neuralgia patients: a randomized clinical trial

Caused by viral infection, postherpetic neuralgia (PHN) is the most common chronic neuropathic pain. Various treatment modalities such as early use of nerve block therapy (NBT) and pulsed radiofrequency (PRF) have been studied in reducing pain, however, no consistent success was achieved in all the patients treated with single regimen. The combined therapy of PRF and NBT with different targeting mechanism are of interest and remains to be determined. Here we investigated the combined effects of pulsed radiofrequency (PRF) with nerve block therapy (NBT) in PHN patients in a prospective randomized clinical trial. Sixty PHN patients were divided into four groups (n = 15 each): the conventional puncture group (group CP), the nerve block therapy group (group NB), the PRF group (group PRF), and the combined treatment group (PRF combined with nerve block therapy (group CT). To evaluate the extent of remission of hyperalgesia, we recorded the visual analogue scale (VAS) scores during cotton swab reaction before and after treatment and in the resting and active pain states. In addition, blood samples were collected and plasma cytokine and neuropeptides such as interleukin-6 (IL-6), substance P (SP), and β-endorphin (β-EP) were measured by enzyme-linked immunosorbent assay (ELISA) at the admission (basic state), before the operation, and at 12 h postoperatively. The number of adverse events (nausea, vomiting, constipation, puncture point hemorrhage, swelling and redness) within 12 h of the treatment were also documented. Our results showed that VAS scores during cotton swab reaction decreased after treatment in all patients (p < 0.05). Compared to group CP, plasma IL-6 and SP levels decreased (p < 0.05) and β-EP levels increased (p < 0.05) in groups NB, PRF, and CT. There were no significant differences in adverse events among groups (p > 0.05). We found that PRF in combination with NBT increased β-EP levels and decreased plasma IL-6 and SP, thereby alleviating pain and hyperalgesia in PHN patients. Taken together, our data suggest combined therapy of PRF and NBT is effective and safe for PHN patients.

Pulsed Radiofrequency as a Minimally Invasive Treatment Option in Anterior Cutaneous Nerve Entrapment Syndrome: A Retrospective Analysis of 26 Patients

BACKGROUND

Chronic abdominal pain is occasionally due to entrapped intercostal nerve endings (ACNES, abdominal cutaneous nerve entrapment syndrome). If abdominal wall infiltration using an anesthetic agent is unsuccessful, a neurectomy may be considered. Pulsed radiofrequency (PRF) is a relatively new treatment option for various chronic pain syndromes. Evidence regarding a beneficial effect of this minimally invasive technique in ACNES is lacking. The aim was to assess the effectiveness of PRF treatment in ACNES patients.

METHODS

A series of ACNES patients undergoing PRF treatment between January 2014 and December 2015 in two hospitals were retrospectively evaluated. Pain was recorded prior to treatment and after 6 weeks using a numerical rating scale (NRS, 0 (no pain) to 10 (worst possible pain)). Successful treatment was defined as > 50% NRS pain reduction. Patient satisfaction was scored by patient global impression of change (PGIC, 1 = very much worse, to 7 = very much improved).

RESULTS

Twenty-six patients were studied (17 women, median age 47 years, range 18 - 67 years). After 6 weeks, mean NRS score had dropped from 6.7 ± 1.2 to 3.8 ± 2.3 (P < 0.001). A mean 4.9 ± 1.4 PGIC score was reported by then. Short term treatment success (6 - 8 weeks) was 50% (n = 13, 95% CI: 29 - 71), while 8% was pain-free on the longer term (median 15 months). Median effect duration was 4 months (range 2 - 26).

CONCLUSIONS

PRF is temporarily effective in half of patients with ACNES. PRF is safe and may be favored in neuropathic pain syndromes as nerve tissue destruction is possibly limited. A randomized controlled trial determining the potential additional role of PRF in the treatment strategy for ACNES is underway.

Human dorsal root ganglion pulsed radiofrequency treatment modulates cerebrospinal fluid lymphocytes and neuroinflammatory markers in chronic radicular pain

Radicular pain is a common cause of disability. Traditionally treatment has been either epidural steroid injection providing short-term relief or surgery with associated complications. Pulsed radiofrequency (PRF) applied to the dorsal root ganglion (DRG) is a minimally invasive day-care treatment, which is gaining significant clinical acceptance in a selective group of patients with pure radicular pain. Greater insights into the immunomodulatory effects of this procedure may help to further optimise its application and find alternative treatment options. We have examined it's effect on lymphocyte frequencies and secreted inflammatory markers in the cerebrospinal fluid (CSF) and correlated this with clinical outcome to identify clinical markers of chronic radicular pain. Ten patients were recruited for the study. CSF lymphocyte frequencies and levels of cytokines, chemokines and growth factors were quantified using flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively. Clinical assessment utilised Brief Pain Inventory scores. Nine out of ten patients (90%) demonstrated significant reduction in pain severity (p = 0.0007) and pain interference scores (p = 0.0015) three months post-treatment. Our data revealed significant reductions in CD56⁺, CD3^-, NK cell frequencies (p = 0.03) and IFN-γ levels (p = 0.03) in treatment responders, while CD8⁺ T cell frequencies (p = 0.02) and IL-6 levels were increased (p = 0.05). IL-17 inversely correlated with post-treatment pain severity score (p = 0.01) and pre and post-treatment pain interference scores (p = 0.03, p = 0.01). These results support the concept that chronic radicular pain is a centrally mediated neuroimmune phenomenon and the mechanism of action of DRG PRF treatment is immunomodulatory.

Pulse-dose radiofrequency treatment in pain management-initial experience

Radiofrequency procedures have been used for treating various chronic pain conditions for decades. These minimally invasive percutaneous treatments employ an alternating electrical current with oscillating radiofrequency wavelengths to eliminate or alter pain signals from the targeted site. The aim of the continuous radiofrequency procedure is to increase the temperature sufficiently to create an irreversible thermal lesion on nerve fibres and thus permanently interrupt pain signals. The pulsed radiofrequency procedure utilises short pulses of radiofrequency current with intervals of longer pauses to avert a temperature increase to the level of permanent tissue damage. The goal of these pulses is to alter the processing of pain signals, but to avoid relevant structural damage to nerve fibres, as seen in the continuous radiofrequency procedure. The pulse-dose radiofrequency procedure is a technical improvement of the pulsed radiofrequency technique in which the delivery mode of the current is adapted. During the pulse-dose radiofrequency procedure thermal damage is avoided. In addition, the amplitude and width of the consecutive pulses are kept the same. The method ensures that each delivered pulse keeps the same characteristics and therefore the dose is similar between patients. The current review outlines the pulse-dose radiofrequency procedure and presents our institution's chronic pain management studies.