Pulsed radiofrequency in chronic pain

Pulsed Radiofrequency Neuromodulation of the Greater Occipital Nerve for the Treatment of Headache Disorders in Adults: A Systematic Review

Background

Pulsed radiofrequency neuromodulation (PRFN) of greater occipital nerve (GON) is considered in patients with headaches failing to achieve sustained analgesic benefit from nerve blocks with local anesthetic and steroids. However, the evidence supporting this practice is unclear.

Aims

This narrative systematic review aims to explore the effectiveness and safety of GON PRFN on headaches.

Methods

Databases were searched for studies, published up to February 1, 2024, investigating PRFN of GON for adults with headaches. Abstracts and posters were excluded. Primary outcome was change in headache intensity. Secondary outcomes included effect on monthly headache frequency (MHF), mental and physical health, mood, sleep, analgesic consumption, and side-effects. Two reviewers screened and extracted data.

Results

Twenty-two papers (2 randomized controlled trials (RCT), 11 cohort, and 9 case reports/series) including 608 patients were identified. Considerable heterogeneity in terms of study design, headache diagnosis, PRF target and settings, and image-guidance was noted. PRFN settings varied (38-42°C, 40-60 V, and 150-400 Ohms). Studies demonstrated PRFN to provide significant analgesia and reduction of MHF in chronic migraine (CM) from 3 to 6 months; and significant pain relief for ON from six to ten months. Mild adverse effects were reported in 3.1% of cohort. A minority of studies reported on secondary outcomes. The quality of the evidence was low.

Conclusions

Low-quality evidence indicates an analgesic benefit from PRFN of GON for ON and CM, but its role for other headache types needs more investigation. Optimal PRFN target and settings remain unclear. High-quality RCTs are required to further explore the role of this intervention. PROSPERO ID CRD42022363234.

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

Background

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

Methods

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

Results

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

Conclusion

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

1. Lumbosacral radicular pain

INTRODUCTION

Patients suffering lumbosacral radicular pain report radiating pain in one or more lumbar or sacral dermatomes. In the general population, low back pain with leg pain extending below the knee has an annual prevalence that varies from 9.9% to 25%.

METHODS

The literature on the diagnosis and treatment of lumbosacral radicular pain was reviewed and summarized.

RESULTS

Although a patient's history, the pain distribution pattern, and clinical examination may yield a presumptive diagnosis of lumbosacral radicular pain, additional clinical tests may be required. Medical imaging studies can demonstrate or exclude specific underlying pathologies and identify nerve root irritation, while selective diagnostic nerve root blocks can be used to confirm the affected level(s). In subacute lumbosacral radicular pain, transforaminal corticosteroid administration provides short-term pain relief and improves mobility. In chronic lumbosacral radicular pain, pulsed radiofrequency (PRF) treatment adjacent to the spinal ganglion (DRG) can provide pain relief for a longer period in well-selected patients. In cases of refractory pain, epidural adhesiolysis and spinal cord stimulation can be considered in experienced centers.

CONCLUSIONS

The diagnosis of lumbosacral radicular pain is based on a combination of history, clinical examination, and additional investigations. Epidural steroids can be considered for subacute lumbosacral radicular pain. In chronic lumbosacral radicular pain, PRF adjacent to the DRG is recommended. SCS and epidural adhesiolysis can be considered for cases of refractory pain in specialized centers.

Vasodilatory Peripheral Response and Pain Levels following Radiofrequency Stressor Application in Women with Fibromyalgia

Fibromyalgia (FM) is a syndrome of unknown pathogenesis that presents, among other symptoms, chronic widespread musculoskeletal pain. This study aims to analyze the effects of radiofrequency on core body temperature and the peripheral temperature of the dorsal surfaces and palms of the hands and its association with pain levels in patients with FM. A case-control observational study was conducted with a total of twenty-nine women diagnosed with FM and seventeen healthy women. Capacitive monopolar radiofrequency was applied to the palms of the hands using the Biotronic Advance Develops device. Peripheral hand temperature was analyzed using a thermographic camera, and core body temperature was analyzed with an infrared scanner. Pressure pain thresholds (PPTs) and electrical pain were recorded with an algometer and a Pain Matcher device, respectively. A significant decrease was observed in women with FM in pain electrical threshold (95% CI [0.01-3.56], p = 0.049), electrical pain (95% CI [2.87-10.43], p = 0.002), dominant supraspinatus PPT (95% CI [0.04-0.52], p = 0.023), non-dominant supraspinatus PPT (95% CI [0.03-0.60], p = 0.029), and non-dominant tibial PPT (95% CI [0.05-0.89], p = 0.031). Women with FM have increased hypersensitivity to pain as well as increased peripheral temperature after exposure to a thermal stimulus, such as radiofrequency, which could indicate disorders of their neurovascular response.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Phenolysis for Advanced Shoulder Osteoarthritis: A Case Series of a Novel Ultrasound-Guided Approach to Anterior and Posterior Glenohumeral Articular Nerve Branches

INTRODUCTION

The shoulder is one of the joints most affected by osteoarthritis, with a prevalence of almost 20% in adults over 65 years of age. Various treatments have been proposed to control osteoarthritis pain, including radiofrequency, pulsed and thermal, and recently cryoanalgesia. We propose in this series of cases a new approach to analgesic therapy with chemical denervation with phenol.

MATERIALS AND METHOD

Patients who underwent phenolysis for shoulder osteoarthritis at our institutions in Italy and Australia between August 2022 and May 2023 were included. All patients included in our report provided written consent for publication. This chemical neurolysis technique consisted of two injections. First, the anterior shoulder capsule was denervated by a modified deep SHAC (Shoulder Anterior Capsule) approach to cover the anterior terminal articular branches of the axillary nerve, lateral pectoral nerve, and subscapularis nerve. Second, the posterior shoulder capsule was denervated by a posterior glenoid approach to cover the terminal articular branches of the suprascapular nerve (SSN).  Results: We included a total of 11 patients in this case series. Ten of 11 patients were affected by shoulder osteoarthritis, of which three had rotator cuff tendinopathy and three had full-thickness cuff tears. One patient had chronic subluxation of a shoulder prosthesis. After treatment, all patients significantly reduced pain immediately after treatment and, two weeks later, recovered joint movement and improved quality of life. No adverse events or loss of motor function following treatment.

CONCLUSION

We presented a novel chemical approach to shoulder denervation, which was shown to be another effective way of improving pain and function in advanced glenohumeral arthritis.

Neurostimulation for Chronic Pain: A Systematic Review of High-Quality Randomized Controlled Trials With Long-Term Follow-Up

OBJECTIVE

This study aimed to review the best evidence on the long-term efficacy of neurostimulation for chronic pain.

MATERIALS AND METHODS

We systematically reviewed PubMed, CENTRAL, and WikiStim for studies published between the inception of the data bases and July 21, 2022. Randomized controlled trials (RCTs) with a minimum of one-year follow-up that were of high methodologic quality as ascertained using the Delphi list criteria were included in the evidence synthesis. The primary outcome was long-term reduction in pain intensity, and the secondary outcomes were all other reported outcomes. Level of recommendation was graded from I to III, with level I being the highest level of recommendation.

RESULTS

Of the 7119 records screened, 24 RCTs were included in the evidence synthesis. Therapies with recommendations for their usage include pulsed radiofrequency (PRF) for postherpetic neuralgia, transcutaneous electrical nerve stimulation for trigeminal neuralgia, motor cortex stimulation for neuropathic pain and poststroke pain, deep brain stimulation for cluster headache, sphenopalatine ganglion stimulation for cluster headache, occipital nerve stimulation for migraine, peripheral nerve field stimulation for back pain, and spinal cord stimulation (SCS) for back and leg pain, nonsurgical back pain, persistent spinal pain syndrome, and painful diabetic neuropathy. Closed-loop SCS is recommended over open-loop SCS for back and leg pain. SCS is recommended over PRF for postherpetic neuralgia. Dorsal root ganglion stimulation is recommended over SCS for complex regional pain syndrome.

CONCLUSIONS

Neurostimulation is generally effective in the long term as an adjunctive treatment for chronic pain. Future studies should evaluate whether the multidisciplinary management of the physical perception of pain, affect, and social stressors is superior to their management alone.

The Anti-Inflammatory Action of Pulsed Radiofrequency-A Hypothesis and Potential Applications

In 2013, it was reported that pulsed radiofrequency (PRF) could be applied to obtain a systemic anti-inflammatory effect. Patients with chronic pain and patients with an inflammatory condition from other disciplines could potentially profit from this finding. At that time, intravenous application was used, but since then, it became clear that it could be applied transcutaneously as well. This procedure was named RedoxPRF. This can be used both for regional and for systemic application. Recently, the basic element of the mode of action has been clarified from the analysis of the effects of PRF on a standard model of muscle injury in rats. The objective of this paper is to present a hypothesis on the mode of action of RedoxPRF now that the basic mechanism has become known. Cell stress causes an increased production of free radicals, disturbing the redox equilibrium, causing oxidative stress (OS) either directly or secondarily by other types of stress. Eventually, OS causes inflammation and an increased sympathetic (nervous) system activity. In the acute form, this leads to immune paralysis; in the chronic form, to immune tolerance and chronic inflammation. It is hypothesized that RedoxPRF causes a reduction of free radicals by a recombination of radical pairs. For systemic application, the target cells are the intravascular immune cells that pass through an activated area as on an assembly line. Hypothesis conclusions: 1. RedoxPRF treatment works selectively on OS. It has the unique position of having a point of engagement at the most upstream level of the train of events. 2. RedoxPRF has the potential of being a useful tool in the treatment of inflammatory diseases and possibly of stage 4 cancer. 3. In the treatment of chronic pain, RedoxPRF is an entirely new method because it is different from ablation as well as from stimulation. We propose the term "functional restoration". 4. Controlled studies must be conducted to develop this promising new field in medicine further.

Previous Lumbar Spine Surgery Decreases the Therapeutic Efficacy of Dorsal Root Ganglion Pulsed Radiofrequency in Patients with Chronic Lumbosacral Radicular Pain

Chronic lumbosacral radicular pain (CLRP) as a possible adverse consequence of lumbar spine surgery represents a serious medical challenge. Pulsed radiofrequency of dorsal root ganglion (PRF-DRG) treatment is known to be effective in alleviating CLRP. This retrospective study compares the efficacy of a single CT-guided PRF-DRG procedure in the treatment of unilateral CLRP between patients without (non-PSS) and with (PSS) previous lumbar spine surgery. Non-PSS and PSS groups included 30 and 20 patients, respectively. Outcomes (pain intensity and disability) were evaluated by means of the visual analog scale (VAS) and Oswestry disability index (ODI) immediately after the procedure (VAS), as well as three and six months after the procedure, respectively. Non-PSS group showed a significant (p ˂ 0.001) decrease of VAS (median) at all follow-up intervals (from 6 to 4; 4; 4.5 points, respectively). The PSS group showed a significant yet transient VAS (median) decrease (from 6 to 5 points) immediately after the procedure only (p < 0.001). The decrease of VAS was more pronounced in the non-PSS group after three and six months (p = 0.0054 and 0.011, respectively) in intergroup comparison. A relative decrease of VAS ≥ 50% during follow-up was achieved in 40%; 43.3%; 26.7% (non-PSS), and 25%; 5%; 0% (PSS) of patients. ODI (median) significantly decreased in the non-PSS group (from 21.5 to 18 points) at three and six months (p = 0.014 and 0.021, respectively). In conclusion, previous lumbar spine surgery decreases the therapeutic efficacy of PRF-DRG procedure in CLRP patients.

Pulsed Radiofrequency Decreases pERK and Affects Intracellular Ca2+ Influx, Cytosolic ATP Level, and Mitochondrial Membrane Potential in the Sensitized Dorsal Root Ganglion Neuron Induced by N-Methyl D-Aspartate

Background

The molecular mechanism of pulsed radiofrequency (PRF) in chronic pain management is not fully understood. Chronic pain involves the activation of specific N-Methyl D-Aspartate receptors (NMDAR) to induce central sensitization. This study aims to determine the effect of PRF on central sensitization biomarker phosphorylated extracellular signal-regulated kinase (pERK), Ca²⁺ influx, cytosolic ATP level, and mitochondrial membrane potential (Δψm) of the sensitized dorsal root ganglion (DRG) neuron following NMDAR activation.

Methods

This study is a true experimental in-vitro study on a sensitized DRG neuron induced with 80 µM NMDA. There are six treatment groups including control, NMDA 80 µM, Ketamine 100 µM, PRF 2Hz, NMDA 80 µM + PRF 2 Hz, and NMDA 80 µM + PRF 2 Hz + ketamine 100 µM. We use PRF 2 Hz 20 ms for 360 seconds. Statistical analysis was performed using the One-Way ANOVA and the Pearson correlation test with α=5%.

Results

In the sensitized DRG neuron, there is a significant elevation of pERK. There is a strong correlation between Ca²⁺, cytosolic ATP level, and Δψm with pERK intensity (p<0.05). PRF treatment decreases pERK intensity from 108.48 ± 16.95 AU to 38.57 ± 5.20 AU (p<0.05). PRF exposure to sensitized neurons also exhibits a Ca²⁺ influx, but still lower than in the unexposed neuron. PRF exposure in sensitized neurons has a higher cytosolic ATP level (0.0458 ± 0.0010 mM) than in the unexposed sensitized neuron (0.0198 ± 0.0004 mM) (p<0.05). PRF also decreases Δψm in the sensitized neuron from 109.24 ± 6.43 AU to 33.21 ± 1.769 AU (p<0.05).

Conclusion

PRF mechanisms related to DRG neuron sensitization are by decreasing pERK, altering Ca²⁺ influx, increasing cytosolic ATP level, and decreasing Δψm which is associated with neuron sensitization following NMDAR activation.

Increasing relief with repeated botulinum neurotoxin A injections in a rare case of hemi facial spasm with contralateral trigeminal autonomic orofacial pain and occipital neuralgia: A case report

Ipsilateral hemi facial spasm, trigeminal autonomic orofacial pain and occipital neuralgia may occur due to close proximity of V and VII nerves in pons and inter-neuronal interconnections of trigeminocervical complex. In this report, we describe management of a patient with long standing untreated left hemi facial spasm of ten years with contralateral trigeminal autonomic orofacial pain and occipital neuralgia present for last five years. Repeated intramuscular injections of Botulinum neurotoxin A were given for hemi facial spasm which completely resolved the twitches for 5-8 months with decreased baseline twitches noted before next cycle of injections. Addition of Botulinum neurotoxin A in nerve block injections for occipital neuralgia resulted in prolonged relief of five months and decreased baseline pain scores. Addition of Botulinum neurotoxin A to nerve block injections for trigeminal autonomic orofacial pain decreased autonomic features and baseline pain scores.

[Thermal radiofrequency as an alternative in the treatment of persistent localized neuropathic pain due to entrapment of a collateral nerve of the hand]

Localized neuropathic pain (LNP) is a relatively common cause of musculoskeletal pain, which can be present in up to 60% of neuropathic pain conditions. Its appearance can be associated with numerous pathologies (herpes, diabetes, etc.). A less common cause would be the direct compression of a peripheral nerve branch. Its diagnosis is usually clinical since complementary tests such as neurophysiological tests do not provide definitive data. As therapeutic measures we have oral analgesics, anticonvulsants, analgesic skin patches and interventional actions, including radiofrequency (RF). Thermal RF consists in the transmission of an electric impulse through a needle reaching a controlled increase in temperature with which a nerve ablative injury is achieved. We present a clinical case where thermal RF of the collateral nerve of the hand is proposed as a therapeutic alternative, whose entrapment is the cause of pain, obtaining a satisfactory clinical improvement.

Neurosurgical Ablation for Pain: A Technology Review

Neurosurgical ablative procedures for pain have dramatically transformed over the years. Compared to their precursors, present day techniques are less invasive and more precise as a result of advances in both device engineering and imaging technology. From a clinical perspective, understanding the strengths and drawbacks of modern techniques is necessary to optimize patient outcomes. In this review, we provide an overview of the major contemporary neuroablative modalities/technologies used for treating pain. We will compare and contrast these modalities from one another with respect to their intraoperative monitoring needs, invasiveness, range of access, and lesion generation. Finally, we will provide a brief commentary on the future of neuroablation given the advent of neuromodulation options for pain control.

The diagnostic and therapeutic challenges of medial plantar neuropathy in jogger's foot: a case report

Jogger's foot is characterised by a neuropathic pain along the medial arch of the foot caused by compression of the medial plantar nerve. It is more common in runners, especially when there is an anatomical predisposition or some extrinsic factor that may exert compression on the nerve. This article presents the case of a 59-year-old man, who had pain and paraesthesia along the medial plantar arch of the left foot, lasting for several months. Despite having undergone some conservative treatments (plantar orthosis and physiotherapy) and minimal invasive procedures (cortico-anaesthetic injection and shockwave therapy) the symptoms persisted and amyotrophy of the abductor hallucis muscle became clinically evident. At this point, a magnetic resonance image was taken, showing compression of the medial plantar nerve at the intersection of the flexor hallucis longus and the flexor digitorum longus tendons. Ultrasound-guided treatment with pulsed radiofrequency of the medial plantar nerve was then proposed to try and modulate his chronic neuropathic pain. After the procedure, the patient reported immediate relief of the symptoms, which were maintained over 6 months of follow up after the procedure. This case report illustrates a rare and frequently misdiagnosed cause of midfoot pain and its management using electromagnetic modulation of peripheral nerves by pulsed radiofrequency. This seems to be an effective technique, with long-lasting results.

The Mechanism of Action between Pulsed Radiofrequency and Orthobiologics: Is There a Synergistic Effect?

Radiofrequency energy is a common treatment modality for chronic pain. While there are different forms of radiofrequency-based therapeutics, the common concept is the generation of an electromagnetic field in the applied area, that can result in neuromodulation (pulsed radiofrequency—PRF) or ablation. Our specific focus relates to PRF due to the possibility of modulation that is in accordance with the mechanisms of action of orthobiologics. The proposed mechanism of action of PRF pertaining to pain relief relies on a decrease in pro-inflammatory cytokines, an increase in cytosolic calcium concentration, a general effect on the immune system, and a reduction in the formation of free radical molecules. The primary known properties of orthobiologics constitute the release of growth factors, a stimulus for endogenous repair, analgesia, and improvement of the function of the injured area. In this review, we described the mechanism of action of both treatments and pertinent scientific references to the use of the combination of PRF and orthobiologics. Our hypothesis is a synergic effect with the combination of both techniques which could benefit patients and improve the life quality.

Effect of CT-Guided Gasserian Ganglion Block with Local Anesthetics and Steroids on Acute/Subacute Zoster-Related Trigeminal Neuralgia: A Multicenter Retrospective Study

Purpose

To further evaluate the effects of gasserian ganglion block treatment with local anesthetics and steroids on patients with acute/subacute zoster-related trigeminal neuralgia.

Patients and Methods

This is a multicenteric retrospective study which included patients between the ages of 26–92 years, who suffered from acute/subacute zoster-related trigeminal neuralgia and had undergone CT-guided gasserian ganglion block. The medical records of these patients between January 13, 2016 and August 25, 2021 were retrieved, and the patients were followed up for 6 months. Follow-up outcomes were Numerical Rating Scale (NRS) scores, medications and dosage. The effective rate was defined as the number of cases with NRS score reduction of >50%/total number of cases×100% at 12 weeks postoperatively.

Results

The postoperative NRS scores were significantly decreased in all patients (P < 0.05), and NRS scores in acute zoster group were lower than those in subacute zoster group at different time points (P < 0.05). The percentage of patients who had a reduction of medication use value of >50% was 56.4% and the effective rate was 66.7% in all patients, at 3 months after the block treatment. There was no significant difference in the reduction of medication use value of >50% and the effective rates between the two groups. There were no intracranial hemorrhage, infection or other serious adverse effects in either groups.

Conclusion

CT-guided gasserian ganglion block with local anesthetics and steroids can be an effective and safe technique to relieve the pain of acute/subacute zoster-related trigeminal neuralgia.

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

INTRODUCTION

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

METHODS AND ANALYSIS

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

ETHICS AND DISSEMINATION

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

PROSPERO REGISTRATION NUMBER

CRD42022297804.

[Clinical practice guideline for the treatment of spasticity: Consensus and algorithms]

Spasticity is a complex phenomenon of extremely variable clinical expression, a dynamic and evolutionary process that can condition the activity and treatment of the patient. The current recommendation for early treatment aims to avoid progression and complications, and involves an individualized approach based on a wide range of pharmacological and non-pharmacological measures. This guide results from a forum of expert specialists who faced some frequent uncertainties in the assessment process and therapeutic approach of the spastic patient such as the suitability of initiating treatment, considerations for initiating, continuing and ceasing treatment with botulinum toxin, adjuvant treatments, pain or follow-up. The result is one algorithm of decision for the therapeutic approach of spasticity. Both scientific progress and the exchange of clinical experience on which this guide is based, can support decision-making on some areas of gloom that we find in daily practice.

Efficacy of Internal Heat Acupuncture Combined with High-Voltage Long-Duration Pulsed Radiofrequency on Subacute Postherpetic Neuralgia: A Retrospective Study

Objectives

This study aims at investigating the internal heat acupuncture (IHA) combined with the high-voltage long-duration pulsed radiofrequency (PRF) therapeutic effect on subacute postherpetic neuralgia (PHN).

Methods

This retrospective study comprised 81 cases with PHN. They were divided into three groups: IHA combined with the high-voltage long-duration PRF group (IHA-PRF), intradermal injection combined with the high-voltage long-duration PRF group (II-PRF), and the high-voltage long-duration PRF group. The pain numerical rating score (NRS), IL-6, Gal-3, and blood glucose levels were recorded before and after treatment.

Results

Compared with before treatment, NRS scores of the three groups were all decreased at each time point. NRS scores of the IHA-PRF group patients decreased significantly in comparison to the PRF group at 1, 4, 8, and 12 weeks following treatment, while group II-PRF only decreased significantly at one week following treatment. Compared with groups II-PRF and PRF, respectively, IL-6 and Gal-3 levels in plasma of patients in group IHA-PRF were significantly decreased at 4 and 12 weeks after treatment. The effective rate of group IHA-PRF was 88.9%, which was considerably more than the other groups, II-PRF (63.0%) and PRF (63.0%). Compared with group II-PRF, patients' blood glucose levels in IHA-PRF and PRF groups significantly decreased three days and one week after treatment.

Conclusion

Internal heat acupuncture combined with high-voltage long-duration pulsed radiofrequency has a satisfactory therapeutic effect on subacute PHN and has no obvious adverse reactions, which is especially suitable for patients with poor blood glucose control.

Short-Term Spinal Cord Stimulation or Pulsed Radiofrequency for Elderly Patients with Postherpetic Neuralgia: A Prospective Randomized Controlled Trial

Background. Postherpetic neuralgia (PHN) is the most common and severe complication after varicella-zoster infection, especially in elderly patients. PHN is always refractory to treatment. Both pulsed radiofrequency (PRF) and short-term spinal cord stimulation (stSCS) have been used as effective analgesia methods in clinic. However, which technique could provide better pain relief remains unknown. Objectives. This study is aimed at evaluating the efficacy and safety of PRF and stSCS in elderly patients with PHN. Study Design. A prospective, randomized-controlled study. Setting. Department of Pain Management, the Second Affiliated Hospital of Guangzhou Medical University. Methods. A total of 70 elderly patients with PHN were equally randomized to the PRF group or stSCS group. Patients in the PRF group received PRF treatment, while patients in the stSCS group received stSCS treatment. The primary outcome was the effective rate. The secondary outcomes included the Visual Analogue Scale (VAS), the 36-Item Short Form Health Survey Questionnaire (SF-36), and the pregabalin dosage. All outcomes were evaluated at baseline and at different postoperative time points. Results. At 12 months after surgery, the effective rate reached 79.3% in stSCS group, while 42.1% in PRF group. The effective rate was significantly higher in the stSCS group than in the PRF group at 3, 6, and 12 months after surgery. VAS scores decreased significantly at each postoperative time point in both groups ( $P<0.001$ ). The VAS scores were significantly lower in the stSCS group than in the PRF group at 3, 6, and 12 months after surgery. SF-36 scores (bodily pain and the physical role) were significantly improved at each postoperative time point in both groups ( $P<0.001$ ). The SF-36 scores were significantly higher in the stSCS group than in the PRF group at some postoperative time points. The pregabalin dosage was significantly lower in the stSCS group than in the PRF group at 3, 6, and 12 months after surgery. Limitations. A single-center study with a relatively small sample size. Conclusions. Both PRF and stSCS are effective and safe neuromodulation techniques for elderly patients with PHN. However, stSCS could provide better and longer-lasting analgesic effect compared to PRF.

Clinical Efficacy of Pulsed Radiofrequency Combined with Intravenous Lidocaine Infusion in the Treatment of Subacute Herpes Zoster Neuralgia

Objective

Under the guidance of a digital subtraction angiography (DSA) machine, via fluoroscopic imaging techniques, patients diagnosed with herpes zoster neuralgia at the subacute stage, where self-reported pain lasts between 30 and 90 days, were treated with nerve pulsed radiofrequency surgery combined with intravenous lidocaine infusion or saline infusion as control. This study explores the clinical efficacy, safety, and clinical value of the combined treatment compared with nerve pulsed radiofrequency surgery alone.

Methods

In this study, 72 patients diagnosed with herpes zoster neuralgia at the subacute stage were randomly divided into two groups with matched gender, age, and clinical symptoms. Both groups received pulsed radiofrequency surgery for the affected nerve segments under DSA fluoroscopy. Five days after the operation, 0.9% saline was administered daily for five consecutive days (50 ml per day, intravenous infusion) to group A (n = 36), and lidocaine was administered daily for five consecutive days (3 mg per kg per day, intravenous infusion) to group B (n = 36). Patients with poor pain control during the treatment were given 10 mg morphine tablets for pain relief to reach visual analog scale (VAS) ≤4 points. Data of the following categories were collected: VAS score, self-rating anxiety scale (SAS) score, depression self-rating scale (SDS) score, Pittsburgh sleep quality score (PSQI), 45 body area rating scale score, skin temperature measurement using infrared thermography, analgesic drug use before and after treatment at six different time points: before surgery (T₀), one day after surgery (T₁), three days after surgery (T₂), five days after surgery (T₃), one month after surgery (T₄), and two months after surgery (T₅). Blood was collected from all patients in the morning before surgery and right after the last intravenous infusion of lidocaine at T₃. Serum inflammatory indexes including white blood cell count, lymphocyte count, neutrophils count, erythrocyte sedimentation rate count, C-reactive protein (CRP) level, calcitonin gene-related peptide (CGRP) level, and interleukin-6(IL-6) level were determined. Lastly, the incidence of complications and adverse reactions throughout the study was recorded.

Results

In total, 64 out of 72 patients completed the whole study. Two patients met the exclusion criteria in group A, one patient refused to participate, and one was lost to follow-up. Two patients met the exclusion criteria in group B, and two were lost to follow-up. Three patients in group B experienced vomiting during lidocaine treatment. The adverse symptom was relieved after symptomatic treatment. No patients in the two groups had severe complications such as hematoma at the puncture site, pneumothorax, and nerve injury. Compared with before treatment, the mean of VAS score, SAS score, SDS score, PSQI score, and skin temperature of both groups at each time point after interventional surgery were all significantly reduced. Furthermore, at each time point after surgery, the above indicators of group B patients were significantly lower than those of group A patients. After treatment, the consumption of analgesics in both groups was significantly lower than before treatment. Compared with group A, the consumption of analgesics was also significantly lower in group B. In addition, serum inflammatory indexes at the T₃ time point of the two groups of patients were lower than T₀. Among them, the erythrocyte sedimentation rate, CRP level, CGRP level, and interleukin-6 level of group B were significantly lower than those of group A. The incidence of postherpetic neuralgia (PHN) in group B patients (6.25%) was also lower than that in group A patients (25%).

Conclusion

DSA-guided nerve pulse radiofrequency surgery combined with intravenous lidocaine infusion can effectively relieve pain in patients diagnosed with herpes zoster nerves at the subacute stage, reduce the number of analgesic drugs used in patients, reduce postherpetic neuralgia incidence rate, and improve sleep and quality of life.

Application of Morphological Characteristics of Radiofrequency Lesions to Individual Parameters of Thermal Rhizolysis for Trigeminal Neuralgia

Thermic rhizolysis is a reliable therapy for pharmaco-resistant trigeminal neuralgia. Temperature, duration of electrocautery and needle location can influence the efficacy and complications of the therapy. We performed experimental thermocautery on egg white with increasing parameters of time (30-120s) and temperature (60-95°C); we analyzed the shape, size and volume of the thermic lesions produced. We developed a surgical procedure to assess peroperatively the probable thermocoagulation field and its geometric relations with the trigeminal roots and other anatomical structures of Meckel's cave, and we individually adapted the parameters of rhizolysis to optimize the results. This procedure was applied on 22 patients with trigeminal neuralgia. The volume of the lesions produced by rhizolysis on egg white had a spheroidal shape and increased linearly with the level of temperature and the time of electrocautery from 1.595mm³ (SD0.38) to 54.454mm3(SD10.41); higher temperatures induced larger thermocoagulation fields than longer time periods. The calculated volumes measured at all levels of temperature and time were applied in vivo on the patient stereotactic planning during the thermocoagulation procedure in order to select the optimal parameters for rhizolysis. The median values used were 75°C(range70-85°C) and 60s(range45-60s). At 6-month follow-up, pain outcome was Barrow-Neurological-Institute class-I for 72.7%, IIIa for 22.7% and IIIb for 4.6%; the only complication due to rhizolysis was mild facial numbness in 13 subjects (59%) at 6-month follow-up. We conclude that geometric analysis of the position of the electrode before trigeminal thermocoagulation with morphometric-related individual adaptation of treatment parameters could avoid serious injuries and optimize pain control.

Investigation of Effectiveness of Pulsed Radiofrequency With Multifunctional Epidural Electrode for Low Back Pain

Aim: Low back pain affects many people at some point in their life. Whenever pharmacologic and other conservative treatments of chronic pain fail, ablative and interventional methods are attempted on the assumption that interrupting nerve conduction prevents central pain cognition. Pulsed radiofrequency using multifunctional epidural electrodes can be used for multiple etiologies of chronic low back and leg pain with a low complication rate and minimal side effects. Methods: The records of the 188 patients who underwent pulsed radiofrequency with multifunctional epidural electrode between October 2014 and March 2017 in Algology clinic were examined retrospectively. Visual analogue scale (VAS) for pain, response to straight leg raising test (SLR), lumbar range of motion, analgesic use, patient satisfaction score, need for open operation or other interventional procedure were collected.

Results: VAS and SLR tests were found to be significantly improved compared with the preoperative values. The VAS scores at the 10th day and first, third and sixth months were significantly decreased compared to baseline scores (p<0.001). Also, SLR tests were significantly improved compared to baseline scores at the same intervals (p<0.001).

Conclusion: Pulsed radiofrequency with multifunctional epidural electrode is a safe and effective method for low back pain which is caused by several pathologies.

Pulsed Radiofrequency of the Occipital Nerves: Results of a Standardized Protocol on Chronic Headache Management

BACKGROUND

Pulsed radiofrequency (PRF) of the occipital nerves has neuromodulative properties and is used for chronic pain management. However, its role in various types of chronic headaches has not been adequately investigated so far.

OBJECTIVES

Τhis was an observational, open-label, prospective study aiming to assess the efficacy of PRF of occipital nerves on various types of chronic headache management.

METHODS

Patients with chronic headaches followed up at the pain management unit were scheduled for PRF of both occipital nerves after a positive diagnostic nerve block. PRF was applied following a standardized protocol at 42°C, and the number of headaches per month was assessed as a primary outcome at baseline (before treatment), as well as after 1, 3, and 6 months. Pain intensity during headache crises was recorded using the Numeric Rating Scale (NRS, 0 - 10).

RESULTS

Fifty-seven patients suffering from chronic migraines, cluster headaches, tension-type headaches, and occipital neuralgia were studied. PRF significantly improved the number of headache episodes per month, as well as the pain intensity of the crises. The median number of headache episodes per month was significantly reduced in patients with migraine, from 14.5 to 4 after 1 month, and to 6.5 after 6 months. The same was seen for patients with clusters, who were also improved. A statistically significant reduction in NRS values over time was seen for all types of headaches.

CONCLUSIONS

PRF of the occipital nerves can lead to a reduction of the number of headache episodes per month, improving the intensity of pain during each episode.

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Clinical Outcome of Pulsed-Radiofrequency Combined With Transforaminal Epidural Steroid Injection for Lumbosacral Radicular Pain Caused by Distinct Etiology

BACKGROUND

Lumbosacral radicular pain (LSRP) can be caused by disc herniation, spinal stenosis, and failed back surgery syndrome. The clinical effect of pulsed-radiofrequency (PRF) combined with transforaminal epidural steroid injection (TESI) for radiating pain in different population remains unclear.

METHODS

We retrospectively reviewed the medical recordings of patients with LSRP caused by different etiologies, who underwent PRF and TESI treatment. The primary clinical outcome was assessed by a 10-point Visual Analog Scale (VAS) pre- and post-treatment.

RESULTS

A total of 34 LSRP patients were identified and classified into 3 subgroups (disc herniation, spinal stenosis, and failed back surgery syndrome). The overall immediate pain reduction was 4.4 ± 1.1 after procedure. After a median follow-up of 9.5 months, the VAS decreased from 6.5 ± 1.0 to 2.4 ± 1.9 at the last follow-up.

CONCLUSION

PRF combined with TESI is an effective approach to treat persistent LSRP in distinct population.

Injectable Affinity and Remote Magnetothermal Effects of Bi-Based Alloy for Long-Term Bone Defect Repair and Analgesia

As alternatives, metallic/nonmetallic bone graft materials play significant roles in bone defect surgery to treat external trauma or bone disease. However, to date, there are rather limited long-term implantable materials owning to in situ molding incapability of metallics and poor mechanical property of nonmetallics. Here, Bi-based low melting point alloy, with unique properties of injectability, solid-liquid phase transition, mechanical capability, and biocompatibility, present obvious long-lasting bone affinity as the excellent artificial bone-substitute. It is particularly necessary to point out that the targeted injected Bi alloy remains in its original position for up to 210 days without moving, as well as, displays good osseointegration ability to resolve repeated revision trauma caused by losing bone repair material. Additionally, with outstanding electrical and thermal conductivity, an unconventional way using Bi alloy to realize very beneficial hyperthermia analgesia via non-invasive wireless energy delivery is first proposed, which avoids adverse effects on bone remodeling inflicted by traditional drugs. The significantly decreased expression of pain sensitizing factor, such as, interleukin-6, neuropeptide substance, and transient receptor potential vanilloid 1 reveals the potential mechanism of hyperthermia analgesia. The present findings suggest the combination therapy of Bi alloy in bone repair and analgesia, which owns far-reaching clinical application value.

Efficacy and safety of pulsed radiofrequency modulation of thoracic dorsal root ganglion or intercostal nerve on postherpetic neuralgia in aged patients: a retrospective study

BACKGROUND

Postherpetic neuralgia (PHN) is common in elderly patients and can be alleviated by pulsed radiofrequency (PRF). However, PRF treatments display different efficacy on different nerves. The purpose of this study was to evaluate the efficacy and safety of ultrasound-guided PRF modulation on thoracic dorsal root ganglion (DRG) or intercostal nerve (ICN) for PHN in aged patients and to provide a theoretical basis for clinical treatment.

METHODS

We classified aged patients into two groups, DRG group and ICN group, based on the needle tip position. Visual analogue scale (VAS) and concise health status questionnaire (Short-form 36 health/survey questionnaire, SF-36) were used to evaluate the pain intensity and the life quality of the patients before and 2, 4 and 12 weeks after the PRF treatments. We also recorded the adverse reactions during the treatments.

RESULTS

After the PRF treatment, the scores of VAS and SF-36 (assessing general health perception, social function, emotional role, mental health, and pain) improved significantly in both groups (P < 0.05). The mean VAS score in the DRG group was significantly lower than that in the ICN group 2 weeks after treatment, and remained for 12 weeks. The SF-36 scores in the DRG group were significantly higher than those in the ICN group (P < 0.05). We found a similar incidence of adverse reactions between the two groups (P > 0.05).

CONCLUSIONS

PRF therapy is safe and effective for elderly patients with postherpetic neuralgia. However, PRF treatment in dorsal root ganglion is superior to that in intercostal nerve with improving VAS and SF-36 scores to a greater extent in older patients.

TRIAL REGISTRATION

ChiCTR2100044176 .

Quality of life in chronic pain treated through pulsed radiofrequency therapy: A retrospective study

Anxiety and depression are often symptoms present in people who suffer from chronic pain, compromising the quality of life of these individuals. The objective of this study was to assess whether a pulsed radiofrequency (PRF) treatment, in addition to psychological support intervention, can decrease chronic pain, thereby improving quality of life and restoring psychological well-being.Fifty outpatients with a diagnosis of chronic pain, without any benefit from traditional drug therapies, were selected to perform a PRF treatment in combination with a psychological intervention. They were evaluated before and after the intervention through the Hamilton Anxiety Rating Scale and the Beck Depression Inventory-II for anxiety and depression symptomatology, respectively, the Short Form Health Survey 36 (SF-36) was used to assess the subject's quality of life, and the Numerical Rating Scale was used for pain assessment.The Wilcoxon signed-rank test showed a significant difference in Beck Depression Inventory-II (P < .001), Hamilton Anxiety Rating Scale (P < .01), and Numerical Rating Scale (P = .004). In the SF-36 scores, we observed a significant difference between T0 and T1 in both mental (P < .001) and physical (P < .001) dimensions.This study shows that a chronic pain reduction leads to a decrease of anxiety-depressive symptoms and an improvement in quality of life. PRF seems to be an appropriate method to reduce the chronic pain that influences psychological well-being and quality of life.

Clinical Characteristics and Therapeutic Results in a Series of 68 Patients with Occipital Neuralgia

OBJECTIVE

Cranial pain is a condition that has a negative impact on human lives, and occipital neuralgia is among its causes. This study aims to evaluate the clinical characteristics and therapeutic results of a series of patients with occipital neuralgia.

DESIGN

Prospective registry (observational study).

SETTINGS

Headache outpatient clinic in a tertiary hospital.

SUBJECTS

Sixty-eight cases.

METHODS

Demographic and nosological characteristics have been analyzed, as well as treatment response of occipital neuralgia. All patients were recruited between January 2008 and January 2018, and the diagnosis of occipital neuralgia was made according to the International Headache Society (International Classification of Headache Disorders) criteria being utilized at the time of diagnosis.

RESULTS

Sixty-eight patients were diagnosed with occipital neuralgia, which corresponded to 1.2% of the total number of patients (5,515) who visited our Headache Unit during the aforementioned period. Fifty-four (79.4%) of them were female. Baseline pain was present in 62 (91.1%) patients, and exacerbations in 42 (61.8%). Latency from onset (range) was 27.7 ± 56.1 (1-360) months.

CONCLUSIONS

Occipital neuralgia is an uncommon disorder in the sample explored. The prolonged latency between the onset of symptoms and diagnosis suggests that there should be an increased awareness of this disorder.

Efficacy and Safety of Pulsed Radiofrequency as a Method of Dorsal Root Ganglia Stimulation in Patients with Neuropathic Pain: A Systematic Review

OBJECTIVE

Pulsed radiofrequency (PRF) is a nonablative pain treatment that uses radiofrequency current in short high-voltage bursts, resulting in interruption of nociceptive afferent pathways. We conducted a systematic review with the aim to create a synthesis of evidence about the efficacy and safety of PRF applied to the dorsal root ganglion (DRG) for the treatment of neuropathic pain.

METHODS

We searched MEDLINE, CINAHL, Embase, and PsycINFO through January 8, 2019, as well as ClinicalTrials.gov and the clinical trial register of the World Health Organization. All study designs were eligible. We assessed risk of bias using the Cochrane tool for randomized controlled trials and the Risk Of Bias In Non-Randomized Studies of Interventions (ROBINS-I). We assessed level of evidence using the Oxford tool and quality of evidence with GRADE.

RESULTS

We included 28 studies with participants suffering from lumbosacral, cervical, or thoracic radicular pain, post-herpetic neuralgia, neuropathicbone pain in cancer patients, or carpal tunnel syndrome. Only five studies were randomized controlled trials (RCTs), while others were of nonrandomized designs, predominantly before and after comparisons. A total of 991 participants were included, with a median number (range) of 31 (1-101) participants. Only 204 participants were included in the RCTs, with a median number (range) of 38 (23-62) participants. The overall quality of evidence was low, as the majority of the included studies were rated as evidence level 4 or 5. The quality of evidence was very low.

CONCLUSIONS

Evidence about the efficacy and safety of PRF of the DRG for the treatment of neuropathic pain is based mainly on results from very small studies with low evidence quality. Current research results about the benefits of PRF of the DRG for the treatment of neuropathic pain should be considered preliminary and confirmed in high-quality RCTs with sufficient numbers of participants.

A Randomized Controlled Trial to Compare Analgesia and Functional Improvement After Continuous Neuroablative and Pulsed Neuromodulative Radiofrequency Treatment of the Genicular Nerves in Patients with Knee Osteoarthritis up to One Year After the Intervention

OBJECTIVES

To compare the analgesic and functional outcomes of continuous neuroablative radiofrequency (CNARF) and pulsed neuromodulative radiofrequency (PNMRF) treatment of genicular nerves up to 1 year after the intervention and to identify predictors associated with a successful outcome (defined as an at least 50% reduction in the pre-interventional visual analog scale [VAS] rating) after genicular radiofrequency treatment.

DESIGN

A prospective randomized controlled trial.

SETTING

The Pain Department of the Jerez de la Frontera University Hospital, Cadíz, Spain, from January 2018 until May 2019.

SUBJECTS

Patients with grade 3-4 gonarthritis suffering from knee pain, with a VAS score ≥5 for >6 months.

METHODS

Eligible participants were randomly assigned to receive either CNARF or PNMRF of the superior medial, superior lateral, and inferior medial genicular nerves. The VAS and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores were assessed before and at 1, 6, and 12 months after treatment. Medication use was quantified before and at 6 months after the intervention. Potential characteristics associated with the efficacy of radiofrequency intervention were explored by using multivariable statistical models.

RESULTS

A total of 188 participants were included. The magnitude and duration of beneficial effect and reduction in analgesic use were significantly greater in the CNARF group. Success at 6 months after radiofrequency treatment decreased with grade 4 gonarthritis; higher pre-interventional VAS score; and concomitant depression, anxiety disorder, and diabetes mellitus.

CONCLUSIONS

Therapeutic efficacy and reduction in analgesic consumption were superior after CNARF. Treatment success at 6 months after radiofrequency intervention decreased with more severe gonarthritis; higher pre-interventional pain intensity; and concomitant depression, anxiety disorder, and diabetes mellitus.

Pulsed Radiofrequency Ablation: An Alternative Treatment Modality for Radiation-Induced Brachial Plexopathy

Radiation therapy is used as a form of treatment for various neoplastic diseases. There are many potential adverse effects of this therapy, including radiation-induced neurotoxicity. Radiation-induced brachial plexopathy (RIBP) may occur due to the fibrosis of neural and perineural soft tissues, leading to ischemic damage of the axons and Schwann cells. The dose of radiation exceeds 55 Gy in many patients who develop symptoms [1]. Current incidence in the United States is 1-2%, and RIBP is most commonly seen in patients who have undergone treatment for breast cancer, lung cancer, or lymphoma [1-3]. Common symptoms include numbness, paresthesia, dysesthesia, and occasional numbness of the arm. Pain is present in the shoulder and proximal arm and is typically mild to moderate in severity. Diagnosis is often made based on clinical presentation and evaluation of imaging to rule out concurrent malignant etiologies of the brachial plexus. Current recommended treatment includes physical therapy and medical management with anticonvulsants, tricyclic antidepressants, and selective serotonin-norepinephrine reuptake inhibitors.

Application of Nalbuphine in Trigeminal Ganglion Pulse Radiofrequency Surgery in Patients with Postherpetic Neuralgia

This study aimed to explore the application value of nalbuphine in pulsed radiofrequency operation of trigeminal ganglion in patients with postherpetic neuralgia (PHN). Thirty patients with PHN were randomly divided into the nalbuphine (Nalbu) group and ketorolac tromethamine (KT) group and received CT-guided pulsed radiofrequency surgery on trigeminal ganglion. The numeric rating scale (NRS) scores of patients were recorded at preoperative, intraoperative, and postoperative time points, before going to bed, and the next morning after the operation. In addition, the number of breakthrough pain before operation and within 24 hours after operation, the incidence of nausea and vomiting within 24 hours after surgery, and the patient's sleep quality before and on the day after surgery were evaluated. The outcome data demonstrated that patients treated with nalbuphine had lower NRS scores after the pulse radiofrequency operation during and after the pulse radiofrequency operation compared to those with KT. In addition, nalbuphine effectively decreased the number of breakthrough pain, reduced the occurrence of nausea and vomiting after surgery, and improved the sleep quality. In conclusion, intramuscular injection of nalbuphine 30 min before trigeminal ganglion pulse radiofrequency surgery can be conducive to pain relief and improve the postoperative comfort of patients, providing an effective alternative for the alleviation of PHN in clinic.

A systematic review and meta-analysis of radiofrequency procedures on innervation to the shoulder joint for relieving chronic pain

BACKGROUND AND OBJECTIVE

Studies have reported relief of chronic shoulder pain with non-ablative pulsed neuromodulatory (pRF) or ablative radiofrequency (aRF) procedures on innervation of the shoulder joint but interpretation of these reports is hampered by inconsistent indications, anatomic targets and follow-up. This systematic review was conducted to synthesize the existing literature on procedures employing pRF or aRF for treating chronic shoulder pain.

DATABASES AND DATA TREATMENT

MEDLINE and other medical literature databases were reviewed up to 31 December 2019 for publications on pRF or aRF procedures on shoulder joint innervation to relieve chronic pain. Data on analgesic and functional outcomes measured at any time point following the interventions were extracted. Existing knowledge on innervation of the shoulder joint with relevance to RF procedures was also synthesized.

RESULTS

In all, 42 publications, 7 randomized controlled trials (RCTs) and 35 observational studies, case series or reports were identified. Thirty-six of these publications were on pRF procedure and 29 of these reported procedures exclusively targeting the suprascapular nerve. A meta-analysis of the seven RCTs evaluating pRF indicated no analgesic benefit or functional improvement with this treatment over conventional medical management. Case series and reports on aRF indicate a potential for analgesic benefit but the quality of this evidence was low.

CONCLUSIONS

RF treatments targeting the sensory innervation of the shoulder joint affected by degenerative conditions have the potential to reduce pain but the current evidence does not suggest analgesic or functional benefit (GRADE certainty of evidence-low). Studies of high methodological quality are required to further investigate the role of these interventions.

SIGNIFICANCE

This is a comprehensive review of literature on pulsed (non-ablative) and ablative radiofrequency (RF) procedures for chronic shoulder pain. The systematic review and meta-analysis of 7 trials found that pulsed RF for chronic shoulder pain provided similar analgesia and functional improvement as conservative medical management at three months after the procedures. The case series and reports on ablative RF for shoulder pain indicate possible analgesic benefit but their quality was low. This review highlights the need for studies of a high quality on ablative RF treatments for chronic shoulder pain.

Comparison of Pulsed Radiofrequency, Oxygen-Ozone Therapy and Epidural Steroid Injections for the Treatment of Chronic Unilateral Radicular Syndrome

Background and objectives: For the treatment of chronic unilateral radicular syndrome, there are various methods including three minimally invasive computed tomography (CT)-guided methods, namely, pulsed radiofrequency (PRF), transforaminal oxygen ozone therapy (TFOOT), and transforaminal epidural steroid injection (TFESI). Despite this, it is still unclear which of these methods is the best in terms of pain reduction and disability improvement. Therefore, the purpose of this study was to evaluate the short and long-term effectiveness of these methods by measuring pain relief using the visual analogue scale (VAS) and improvement in disability (per the Oswestry disability index (ODI)) in patients with chronic unilateral radicular syndrome at L5 or S1 that do not respond to conservative treatment. Materials and Methods: After screening 692 patients, we enrolled 178 subjects, each of whom underwent one of the above CT-guided procedures. The PRF settings were as follows: pulse width = 20 ms, f = 2 Hz, U = 45 V, Z ˂ 500 Ω, and interval = 2 × 120 s. For TFOOT, an injection of 4–5 mL of an O₂-O₃ mixture (24 μg/mL) was administered. For the TFESI, 1 mL of a corticosteroid (betamethasone dipropionate), 3 mL of an anaesthetic (bupivacaine hydrochloride), and a 0.5 mL mixture of a non-ionic contrast agent (Iomeron 300) were administered. Pain intensity was assessed with a questionnaire. Results: The data from 178 patients (PRF, n = 57; TFOOT, n = 69; TFESI, n = 52) who submitted correctly completed questionnaires in the third month of the follow-up period were used for statistical analysis. The median pre-treatment visual analogue scale (VAS) score in all groups was six points. Immediately after treatment, the largest decrease in the median VAS score was observed in the TFESI group, with a score of 3.5 points (a decrease of 41.7%). In the PRF and TFOOT groups, the median VAS score decreased to 4 and 5 points (decreases of 33% and 16.7%, respectively). The difference in the early (immediately after) post-treatment VAS score between the TFESI and TFOOT groups was statistically significant (p = 0.0152). At the third and sixth months after treatment, the median VAS score was five points in all groups, without a statistically significant difference (p > 0.05). Additionally, there were no significant differences in the Oswestry disability index (ODI) values among the groups at any of the follow-up visits. Finally, there were no significant effects of age or body mass index (BMI) on both treatment outcomes (maximum absolute value of Spearman’s rank correlation coefficient = 0.193). Conclusions: Although the three methods are equally efficient in reducing pain over the entire follow-up, we observed that TFESI (a corticosteroid with a local anaesthetic) proved to be the most effective method for early post-treatment pain relief.

[Interdisciplinary position paper: the value of radiofrequency denervation in the treatment of chronic pain]

Radiofrequency denervation has been established for many years as an important minimally invasive procedure for the treatment of chronic pain conditions. Positive experiences of many users for various indications are contrasted by a nonuniform evidence. With meticulous patient selection and correct assessment of the indications a longer term reduction of pain, a reduced need for analgesics and an improvement in the quality of life can be achieved. The aim of this interdisciplinary position paper is to present the value of radiofrequency denervation in the treatment of chronic pain. The summarized recommendations of the expert group are based on the available evidence and on the clinical experiences of Austrian centers that frequently implement the procedure. The position paper contains recommendations on patient selection and proven indications. We discribe safety aspects, complications, side effects and contraindications.

CT-Guided Pulsed Radiofrequency at Different Voltages in the Treatment of Postherpetic Neuralgia

Background

Postherpetic neuralgia (PHN) is a form of long-lasting neuropathic pain that can severely affect patients’ quality of life. Pulsed radiofrequency (PRF) has been proven to be effective in treating PHN, but the optimal radiofrequency parameters are still not well defined. This retrospective study aimed to compare the efficacy and safety of CT-guided PRF at three different voltages for the treatment of PHN patients.

Methods

This study included 109 patients with PHN involving the thoracic dermatome who were treated in the Department of Pain Management of Shengjing Hospital, China Medical University, from January 2017 to May 2019. They were divided into three groups based on the PRF voltage used: group A (45 V), group B (55 V), and group C (65 V). The PRF therapy (voltage 45, 55, and 65 V) was performed in all patients by targeting the thoracic dorsal root ganglion. After surgery, patients were followed at 3 days, 1 month, 3 months, 6 months, and 12 months. Observation at each follow-up included basic patient characteristics, visual analog scale (VAS), 36-Item Short Form Health Survey (SF-36) scores, patient satisfaction, complications, and side effects.

Results

Visual analog scale scores decreased and SF-36 scores increased for all patients in the three groups at each post-operative time point (1, 3, 6, and 12 months; all P < 0.01). Pain relief, improvement in quality of life, and overall satisfaction were more significant for patients in group C than for those in groups A and B at the 3-, 6-, and 12-month follow-ups (all P < 0.05). Patients in group B had lower VAS scores and higher overall satisfaction levels than those in group A (both P < 0.01). A small number of patients from each group (n ≤ 3) experienced mild intraoperative and post-operative complications, which bore no relationship with group assignment (all P > 0.05). At post-operative day 3, patients in group C had skin numbness affecting a larger area than patients in the other two groups (both P < 0.05), but the differences were no longer statistically significant at day 30 after the operation. All patients experienced a drop in numbness area of more than 30% after surgery.

Conclusion

Compared with PFR at 45 and 55 V, PFR at 65 V had superior efficacy in treating PNH, with a favorable safety profile.

A Review of the Recent Findings in Minimally Invasive Treatment Options for the Management of Occipital Neuralgia

Occipital neuralgia (ON) is unilateral or bilateral neuralgia in the dermatomal nerve distribution of the greater, lesser or third occipital nerves and is a very common presentation of neuropathic pain. ON, although common and well defined, is still a poorly understood pain syndrome. It often requires invasive treatment for long term and significant pain alleviation; however, the evidence supporting different options is still limited. Several minimally invasive techniques have proven to be efficacious and safe, and the selection depends mostly on response to nerve blocks, patient choice and provider preference. This is a comprehensive review of the latest and seminal literature available about occipital neuralgia and currently available minimally invasive treatment options. It covers the anatomical and physiologic biology at the base of neuralgia, the presentation and diagnostic process. It then reviews the available literature to provide description and comparison of the available methods for alleviation.

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.

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.

Neuroinflammation, Pain and Depression: An Overview of the Main Findings

Chronic pain is a serious public health problem with a strong affective-motivational component that makes it difficult to treat. Most patients with chronic pain suffer from severe depression; hence, both conditions coexist and exacerbate one another. Brain inflammatory mediators are critical for maintaining depression-pain syndrome and could be substrates for it. The goal of our paper was to review clinical and preclinical findings to identify the neuroinflammatory profile associated with the cooccurrence of pain and depression. In addition, we aimed to explore the regulatory effect of neuronal reorganization on the inflammatory response in pain and depression. We conducted a quantitative review supplemented by manual screening. Our results revealed inflammatory signatures in different preclinical models and clinical articles regarding depression-pain syndrome. We also identified that improvements in depressive symptoms and amelioration of pain can be modulated through direct targeting of inflammatory mediators, such as cytokines and molecular inhibitors of the inflammatory cascade. Additionally, therapeutic targets that improve and regulate the synaptic environment and its neurotransmitters may act as anti-inflammatory compounds, reducing local damage-associated molecular patterns and inhibiting the activation of immune and glial cells. Taken together, our data will help to better elucidate the neuroinflammatory profile in pain and depression and may help to identify pharmacological targets for effective management of depression-pain syndrome.

Pulsed radiofrequency for chronic pain: In vitro evidence of an electroporation mediated calcium uptake

Pulsed radiofrequency (PRF) treatments for chronic pain consist in the delivery of a train of sinusoidal electric bursts to the targeted nerve. Despite numerous clinical evidence of its efficiency, the mechanism of action of PRF remains unclear. Since most of the reported biological effects of PRF can be initiated by a calcium influx into the neurons, we hypothesized that PRF may induce a mild electroporation effect causing a calcium uptake. To test this hypothesis, HEK-293 cells were exposed to PRF bursts and cytosolic calcium and Yo-Pro-1 uptake were monitored. After a single burst, calcium peaks were observed for electric fields above 480 V/cm while the uptake of Yo-pro-1 was insignificant. After a train of 120 bursts, the electric fields required to induce a calcium and Yo-pro-1 uptake decreased to 330 V/cm and 880 V/cm respectively. Calcium peaks were not detected when cells were treated in calcium free media. The temperature increase during the treatments was lower than 5 °C in all cases. Finally, the cell response for different burst frequencies and extracellular media conductivities correlated with the induced transmembrane voltage calculated with a numerical model. Our results support the hypothesis of an electroporation mediated calcium influx.

Suprascapular Nerve Pulsed Radiofrequency for Chronic Shoulder Pain in a Pediatric Patient

Pulsed radiofrequency of the suprascapular nerve has shown efficacy in adults with chronic shoulder pain, but its use in pediatrics is relatively new. We present a case of a successful use of pulsed radiofrequency to treat refractory chronic shoulder pain in an adolescent patient. Case Report. We present a 53 kg, 14-year-old female, with a medical history of septic arthritis of the left shoulder within the first month of life leading to persisting pain during childhood. She presented with a complaint of progressive pain starting at age 12, refractory to analgesics including opioids and intra-articular injection of local anesthetic and steroids. After pulsed radiofrequency of the suprascapular nerve, significant pain relief and improvement of the range of motion was obtained. These results were maintained at the 1-, 3-, and 6-month follow-up visits with the pain being reported as mild and manageable with nonsteroidal anti-inflammatory drugs. Conclusion. There is limited data today of the use of pulsed radiofrequency for pediatric chronic pain. We successfully used this intervention in a 14-year-old patient with chronic shoulder pain extrapolating from adult experience and as a last resort after all other treatments had failed.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Evolution of Neuromodulation in the Treatment of Chronic Pain: Forward-Looking Perspectives

Background

The field of neuromodulation is continually evolving, with the past decade showing significant advancement in the therapeutic efficacy of neuromodulation procedures. The continued evolution of neuromodulation technology brings with it the promise of addressing the needs of both patients and physicians, as current technology improves and clinical applications expand.

Design

This review highlights the current state of the art of neuromodulation for treating chronic pain, describes key areas of development including stimulation patterns and neural targets, expanding indications and applications, feedback-controlled systems, noninvasive approaches, and biomarkers for neuromodulation and technology miniaturization.

Results and Conclusions

The field of neuromodulation is undergoing a renaissance of technology development with potential for profoundly improving the care of chronic pain patients. New and emerging targets like the dorsal root ganglion, as well as high-frequency and patterned stimulation methodologies such as burst stimulation, are paving the way for better clinical outcomes. As we look forward to the future, neural sensing, novel target-specific stimulation patterns, and approaches combining neuromodulation therapies are likely to significantly impact how neuromodulation is used. Moreover, select biomarkers may influence and guide the use of neuromodulation and help objectively demonstrate efficacy and outcomes.