A comprehensive review of pulsed radiofrequency in the treatment of pain associated with different spinal conditions

Image-Guided Minimally Invasive Treatment Options for Degenerative Lumbar Spine Disease: A Practical Overview of Current Possibilities

Lumbar back pain is one of the main causes of disability around the world. Most patients will complain of back pain at least once in their lifetime. The degenerative spine is considered the main cause and is extremely common in the elderly population. Consequently, treatment-related costs are a major burden to the healthcare system in developed and undeveloped countries. After the failure of conservative treatments or to avoid daily chronic drug intake, invasive treatments should be suggested. In a world where many patients reject surgery and prefer minimally invasive procedures, interventional radiology is pivotal in pain management and could represent a bridge between medical therapy and surgical treatment. We herein report the different image-guided procedures that can be used to manage degenerative spine-related low back pain. Particularly, we will focus on indications, different techniques, and treatment outcomes reported in the literature. This literature review focuses on the different minimally invasive percutaneous treatments currently available, underlining the central role of radiologists having the capability to use high-end imaging technology for diagnosis and subsequent treatment, allowing a global approach, reducing unnecessary surgeries and prolonged pain-reliever drug intake with their consequent related complications, improving patients' quality of life, and reducing the economic burden.

Anatomo-physiological basis and applied techniques of electrical neuromodulation in chronic pain

Chronic pain, a complex and debilitating condition, poses a significant challenge to both patients and healthcare providers worldwide. Conventional pharmacological interventions often prove inadequate in delivering satisfactory relief while carrying the risks of addiction and adverse reactions. In recent years, electric neuromodulation emerged as a promising alternative in chronic pain management. This method entails the precise administration of electrical stimulation to specific nerves or regions within the central nervous system to regulate pain signals. Through mechanisms that include the alteration of neural activity and the release of endogenous pain-relieving substances, electric neuromodulation can effectively alleviate pain and improve patients' quality of life. Several modalities of electric neuromodulation, with a different grade of invasiveness, provide tailored strategies to tackle various forms and origins of chronic pain. Through an exploration of the anatomical and physiological pathways of chronic pain, encompassing neurotransmitter involvement, this narrative review offers insights into electrical therapies' mechanisms of action, clinical utility, and future perspectives in chronic pain management.

Radiofrequency for chronic lumbosacral and cervical pain: Results of a consensus study using the RAND/UCLA appropriateness method

BACKGROUND

Despite the routine use of radiofrequency (RF) for the treatment of chronic pain in the lumbosacral and cervical region, there remains uncertainty on the most appropriate patient selection criteria. This study aimed to develop appropriateness criteria for RF in relation to relevant patient characteristics, considering RF ablation (RFA) for the treatment of chronic axial pain and pulsed RF (PRF) for the treatment of chronic radicular pain.

METHODS

The RAND/UCLA Appropriateness Method (RUAM) was used to explore the opinions of a multidisciplinary European panel on the appropriateness of RFA and PRF for a variety of clinical scenarios. Depending on the type of pain (axial or radicular), the expert panel rated the appropriateness of RFA and PRF for a total of 219 clinical scenarios.

RESULTS

For axial pain in the lumbosacral or cervical region, appropriateness of RFA was determined by the dominant pain trigger and location of tenderness on palpation with higher appropriateness scores if these variables were suggestive of the diagnosis of facet or sacroiliac joint pain. Although the opinions on the appropriateness of PRF for lumbosacral and cervical radicular pain were fairly dispersed, there was agreement that PRF is an appropriate option for well-selected patients with radicular pain due to herniated disc or foraminal stenosis, particularly in the absence of motor deficits. The panel outcomes were embedded in an educational e-health tool that also covers the psychosocial aspects of chronic pain, providing integrated recommendations on the appropriate use of (P)RF interventions for the treatment of chronic axial and radicular pain in the lumbosacral and cervical region.

CONCLUSIONS

A multidisciplinary European expert panel established patient-specific recommendations that may support the (pre)selection of patients with chronic axial and radicular pain in the lumbosacral and cervical region for either RFA or PRF (accessible via https://rftool.org). Future studies should validate these recommendations by determining their predictive value for the outcomes of (P)RF interventions.

Pulsed Radiofrequency Ablation for Refractory Cancer-Related Leg Pain: A Case Report

Metastatic cancers often lead to distant metastasis, accompanied by debilitating symptoms such as chronic pain, which can be refractory to conventional analgesic modalities. Pulsed radiofrequency ablation (Pulsed RFA) has emerged as a promising intervention for neuropathic pain syndromes, offering long-lasting relief with minimal tissue damage. We present a case of a 36-year-old male with metastatic gastric adenocarcinoma and refractory leg pain due to femoral nerve involvement. Despite aggressive multimodal analgesia, the patient experienced persistent pain, necessitating alternative interventions. Pulsed RFA targeting the right L2-L4 dorsal root ganglia (DRG) provided significant and sustained pain relief, allowing improved functional status and reduced opioid requirements. This case underscores the potential of pulsed RFA as an effective intervention for refractory cancer-related pain, enhancing patients' comfort and quality of life. Further research is warranted to establish its long-term efficacy and safety.

Treatment of Greater Trochanteric Pain Syndrome With Ultrasound-Guided Bipolar Pulsed Radiofrequency of the Trochanteric Branches of the Femoral Nerve: A Case Series of Nine Patients

BACKGROUND

Greater trochanteric pain syndrome (GTPS) is a prevalent cause of lateral hip pain that often leads to significant functional limitations. Conservative treatment options include physical therapy, pharmacological treatment, and more invasive techniques such as corticosteroid injections. However, despite the high success rates reported with corticosteroid injections, a significant number of patients have their symptoms persist or recur.

OBJECTIVES

In this case series, we present the outcomes of nine patients with GTPS who underwent ultrasound-guided bipolar pulsed radiofrequency targeting the trochanteric branches of the femoral nerve. We aim to discuss the effectiveness and safety of this approach.

MATERIAL AND METHODS

Eligible patients referred to our centre underwent ultrasound-guided bipolar pulsed radiofrequency aimed at the trochanteric branches of the femoral nerve. The procedure consisted of one cycle at 42°C for six minutes, followed by the injection of ropivacaine (0.2%, 3 mL) and dexamethasone (12 mg). The Brief Pain Inventory - Short Form (BPI-sf) and Lequesne Algofunctional Index (LAI) were used before the procedure and at the third and sixth months post-procedure. We monitored immediate and late complications, as well as adverse effects.

RESULTS AND DISCUSSION

Our results indicate a favourable outcome for most patients, with an average pain reduction of 76.51% according to their report of the BPI-sf. Additionally, eight out of nine patients experienced at least 50% relief. These findings align with a previous case series, which reported a similar average pain reduction. Before the procedure, most patients were classified as "extremely severe" in the LAI, with an average score of 18.17. Although there was only a slight reduction of 16.84% at the six-month follow-up, this suggests a potential improvement in their functional status. We did not observe any immediate complications or adverse effects after the procedure, nor were any reported at the subsequent follow-ups, which is consistent with existing literature.

CONCLUSIONS

Our study suggests that ultrasound-guided bipolar pulsed radiofrequency treatment is a promising minimally invasive technique for GPTS, especially for patients who do not respond to conservative treatments. Although our case series provides some evidence of effectiveness and safety, further controlled studies on a larger scale are necessary, particularly to compare this intervention with the use of corticosteroid injections alone.

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.

Pulsed Radiofrequency 2 Hz Preserves the Dorsal Root Ganglion Neuron Physiological Ca2+ Influx, Cytosolic ATP Level, Δψm, and pERK Compared to 4 Hz: An Insight on the Safety of Pulsed Radiofrequency in Pain Management

Background

Pulsed radiofrequency (PRF) is beneficial for radicular pain and is commonly administered at pulse frequencies of 2 or 4 Hz. However, its effects on healthy neurons have not yet been widely studied. This study aims to determine the effect of PRF at 2 Hz and 4 Hz on the physiology of healthy dorsal root ganglion (DRG) neurons.

Methods

An in vitro experimental study was conducted using DRG neuron cultures divided into three groups. Control cells received no treatment, one cell group received 20 ms 2 Hz PRF for 360 s, and one cell group received a 4 Hz PRF 10 ms pulse for 360 s with similar energy. Ca2+ influx, mitochondrial membrane potential (Δψm), cytosolic Adenosine triphosphate (ATP), and phosphorylated extracellular signal-regulated kinase (pERK) levels were measured. The data were analyzed using the One-Way ANOVA variance with α=5%.

Results

DRG neurons exposed to PRF 2 Hz did not experience a significant change in Ca2+ influx, whereas PRF 4 Hz caused a significant decrease in Ca2+ influx compared to the basal level. PRF at 2 Hz did not cause a change in Δψm, whereas PRF at 4 Hz caused a significant decrease in Δψm (p<0.05). Both 2 and 4 Hz PRF resulted in a significant elevation in cytosolic ATP concentration, but the 2 Hz PRF had a higher cytosolic ATP than the 4 Hz group (p<0.05). Both 2 and 4 Hz did not show a significant difference in pERK intensity with respect to the control (p>0.05), indicating that there was no significant neuron activation.

Conclusion

Both frequencies did not significantly activate DRG neurons, but with similar energy delivery, PRF 2 Hz preserved the physiological properties of healthy neurons better than PRF 4 Hz did. A 2 Hz PRF is the preferred frequency in clinical applications for neuron-targeted therapy.

Elucidating the Mechanisms of Pulsed Radiofrequency for Pain Treatment

Pulsed radiofrequency is a well-documented treatment option for multiple painful conditions where pulses of energy are delivered close to neural elements. Since its earliest adoption, this technique has gained increasing acceptance as a minimally invasive procedure, and new applications are evolving. Studies have shown microscopic and biochemical changes that reflect beneficial effects; however, the exact mechanism of action is not yet completely understood. To redress this paucity, 11,476 articles of scientific relevance published between 1980 and November 2022 were mined through a search of the PubMed database, arriving at 49 studies both in animals and humans. In general, the experimental studies examined have shown that pulsed radiofrequency induces multiple changes with antinociceptive and neuromodulatory effects. These modifications include changes in neural and glial cells, synaptic transmission, and perineural space. Studies also reveal that pulsed radiofrequency regulates inflammatory responses, cellular signaling proteins, and the expression of genes related to pain transmission, acting in biological processes in structures such as myelin, mitochondria, axons, glial cells, connective tissue, regulation of proteins, ion channels, and neurotransmitters.

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.

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.

Pulsed Radiofrequency Ablation for Orchialgia-A Literature Review

Pulsed radiofrequency, short bursts of radiofrequency energy, has been used by pain practitioners as a non- or minimally neurodestructive technique, an alternative to radiofrequency heat lesions. The clinical advantages and mechanisms of this treatment remain unclear. To review the current clinical implication of the pulsed radiofrequency technique for male patients with chronic scrotal pain. We systematically searched the English literature available at the EMBASE, MEDLINE/PubMed, Google Scholar, and Cochrane Library from inception to 22 November 2022. Only reports on a pulsed radiofrequency application on male patients with chronic scrotal pain were included. The final analysis yielded six reports on the clinical use of pulsed radiofrequency applications in male patients with chronic scrotal pain: six full publications, three case reports, one case series, one prospective uncontrolled pilot study, and one prospective randomized, controlled clinical trial. The accumulation of these data shows that using pulsed radiofrequency generates an increasing interest in pain physicians, radiologists, and urologists for managing chronic scrotal pain. No side effects related to the pulsed radiofrequency technique were reported to date. Further research on the clinical and biological effects is justified. Large sample sizes and randomized clinical trials are warranted.

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.

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.

The Clinical Application of Pulsed Radiofrequency Induces Inflammatory Pain via MAPKs Activation: A Novel Hint for Pulsed Radiofrequency Treatment

Pulsed radiofrequency (PRF) works by delivering short bursts of radiofrequency to a target nerve, thereby affecting nerve signal transduction to reduce pain. Although preliminary clinical investigations have shown that PRF treatment can be used safely as an alternative interventional treatment in patients with refractory pain conditions, unexpected damage to a normal nerve/ganglion is still one of the possible complications of using the PRF strategy. Noxious pain may also be triggered if PRF treatment accidentally damages an intact nerve. However, few studies in the literature have described the intracellular modifications that occur in neuronal cells after PRF stimulation. Therefore, in this study, we evaluated the effects of PRF on unimpaired nerve function and investigated the potential mechanisms of PRF-induced pain. Wistar rats were stimulated with 30-60 V of PRF for 6 min, and mechanical allodynia, cold hypersensitivity, cytokine and matrix metalloproteinase (MMP) production, and mitogen-activated protein kinase activity (p38 MAPK, ERK1/2, JNK/SAPK) were analyzed. The results indicated that PRF stimulation induced a significant algesic effect and nociceptive response. In addition, the protein array and Western blotting analyses showed that the clinical application of 60 V of PRF can induce the activation of MAPKs and the production of inflammatory cytokines and MMPs in the lumbar dorsal horn, which is necessary for nerve inflammation, and it can be suppressed by MAPK antagonist treatment. These results indicate that PRF stimulation may induce inflammation of the intact nerve, which in turn causes inflammatory pain. This conclusion can also serve as a reminder for PRF treatment of refractory pain.

A Multicenter Retrospective Analysis of the Long-Term Efficacy and Safety of a Novel Posterior Sacroiliac Fusion Device

Background

Sacroiliac joint (SIJ) pathology is a cause of low back pain that may be difficult to diagnose and challenging to treat. Open and minimally invasive (MI) lateral approach fusions have been used to treat sacroiliitis over the past two decades. A novel MI posterior approach SIJ fusion technique utilizes a posteriorly placed transfixing device with single point S1/S2 level or mid-segment SIJ fixation (LinQ procedure). Current efficacy and safety data for this novel procedure are lacking.

Objective

To review multicenter retrospective 12 months or greater outcomes data in patients receiving the LinQ procedure, with sub-analysis of patients with prior lumbar fusions.

Methods

Patients with sacroiliitis refractory to conservative care with short-term benefit from diagnostic local anesthetic SIJ injections receiving MI posterior approach SIJ fusion with allograft were included from different centers including both academic and private practice. Numeric rating scale (NRS) scores at baseline (pre-procedural) and most recent follow-up were reviewed across three institutions.

Results

Of 110 patients who received MI SIJ fusion, 50 patients had sufficient data for evaluation of outcomes at least 12 months post-implant. The average time out from implant at follow-up was 612.2 days for all unique patients. The average NRS was 6.98 pre-fusion and 3.06 at last follow-up. Twenty-four patients had prior lumbar surgery of which 17 had prior lumbar fusions. Average NRS for this subset was 6.85 at baseline and 2.86 at last follow-up with an average follow-up of 613.2 days out from implant. No major adverse events or complications were associated with any of the 50 implants.

Conclusion

Real-world evidence suggests that MI posterior SIJ fusion with the LinQ procedure is a viable approach for medically refractory sacroiliitis management with long-term efficacy and safety. Further prospective studies are needed to fully evaluate this technique.

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.

The Effect of Pulsed Radiofrequency on Radicular Pain in Lumbal Herniated Nucleus Pulposus: A Systematic Review and Meta-analysis

Context

Radiofrequency therapy is a medical procedure mainly used to reduce pain with a low complication rate (less than 1%), ease of application, and low cost. This review's objective was to (1) evaluate the pulsed radiofrequency (PRF) effectiveness in treating radicular pain and (2) assess the PRF procedure's safety in managing radicular pain in lumbar herniated nucleus pulposus (HNP).

Methods

A systematic review and meta-analysis. A tertiary care center and an academic medical center. Six full articles with the following features were selected for this review: (1) Articles published in English; (2) studies on the PRF effect on radicular pain in lumbar HNP; and (3) randomized control trials.

Results

The studies showed that the PRF group had a reduction in pain scores at each evaluation. In four of the studies, the PRF group showed a more significant reduction in pain scores than the control, and in two of the studies, the reduction in pain scores was not significant in the PRF group compared to the control. An adverse effect was reported in one patient experiencing increased radicular pain after PRF. Lack of data required for statistical analysis, and lack use of a uniform duration for the PRF procedure by all the studies.

Conclusions

PRF can be used as a promising clinical recommendation for pain management with minimally invasive radicular pain techniques due to lumbar HNP.

Chinese Association for the Study of Pain: Experts consensus on ultrasound-guided injections for the treatment of spinal pain in China (2020 edition)

Spinal pain (SP) is a common condition that has a major negative impact on a patient’s quality of life. Recent developments in ultrasound-guided injections for the treatment of SP are increasingly being used in clinical practice. This clinical expert consensus describes the purpose, significance, implementation methods, indications, contraindications, and techniques of ultrasound-guided injections. This consensus offers a practical reference point for physicians to implement successfully ultrasound-guided injections in the treatment of chronic SP.

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.

A Literature Review of Dorsal Root Entry Zone Complex (DREZC) Lesions: Integration of Translational Data for an Evolution to More Accurate Nomenclature

The purpose of this translational review was to provide evidence to support the natural evolution of the nomenclature of neuromodulatory and neuroablative radiofrequency lesions for pain management from lesions of individualized components of the linear dorsal afferent pathway to “Dorsal Root Entry Zone Complex (DREZC) lesions.” Literature review was performed to collate anatomic and procedural data and correlate these data to clinical outcomes. There is ample evidence that the individual components of the DREZC (the dorsal rami and its branches, the dorsal root ganglia, the dorsal rootlets, and the dorsal root entry zone) vary dramatically between vertebral levels and individual patients. Procedurally, fluoroscopy, the most commonly utilized technology is a 2-dimensional x-ray-based technology without the ability to accurately locate any one component of the DREZC dorsal afferent pathway, which results in clinical inaccuracies when naming each lesion. Despite the inherent anatomic variability and these procedural limitations, the expected poor clinical outcomes that might follow such nomenclature inaccuracies have not been shown to be prominent, likely because these are all lesions of the same anatomically linear sensory pathway, the DREZC, whereby a lesion in any one part of the pathway would be expected to interrupt sensory transmission of pain to all subsequent more proximal segments. Given that the common clinically available tools (fluoroscopy) are inaccurate to localize each component of the DREZC, it would be inappropriate to continue to erroneously refer to these lesions as lesions of individual components, when the more accurate “DREZC lesions” designation can be utilized. Hence, to avoid inaccuracies in nomenclature and until more accurate imaging technology is commonly utilized, the evidence herein supports the proposed change to this more sensitive and inclusive nomenclature, “DREZC lesions.”

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Pulsed radiofrequency as alternative method for phantom pain treatment. Case report

Pulse radiofrequency is a safe method of fighting phantom pain. It creates the possibility of treating cases that have exhausted other therapeutic options.

STUDY PROTOCOL - pulsed radiofrequency in addition to transforaminal epidural steroid injection in patients with acute and subacute sciatica due to lumbosacral disc herniation: rationale and design of a phase III, multicenter, randomized, controlled trial

Lumbosacral disc herniation (LDH) represents the most common cause of sciatica. Currently, there is limited evidence about minimally invasive interventional therapies for the treatment of this condition. This paper presents the protocol for a multicenter, prospective, randomized, controlled, phase III trial evaluating if PRF in addition to TFESI leads to better outcomes in patients with sciatica due to LDH, compared to TFESI alone, during the first year after treatment (Pulsed Radiofrequency in Addition to TFESI for Sciatica [PRATS]). Eligible patients are between 18 and 75 years of age, suffer from sciatica of less than 12-week duration with pain intensity >4 on the Visual Analogue Scale (VAS) and have unilateral LDH compatible with symptoms at MRI. The Medical Ethics Committee of participating hospitals approved the study protocol. Patients will be randomized to receive either combined treatment (PRF and TFESI) or TFESI alone. The primary outcome will be the assessment of pain intensity with VAS at different timepoints from week-1 to 52 after treatment; secondary outcomes will include Roland Disability Questionnaire for sciatica and Oswestry Disability Index, evaluated at 4, 12 and 52 weeks. The follow-up will last 52 weeks for each patient. Statistical analysis will be performed on a per-protocol basis.

Randomized controlled trials between dorsal root ganglion thermal radiofrequency, pulsed radiofrequency and steroids for the management of intractable metastatic back pain in thoracic vertebral body

BACKGROUND

Bone metastasis is a complication of various cancers causing severe pain. The current modalities for the treatment of metastatic axial pain include pharmacological, surgical and vertebral augmentation techniques, each of which has its own challenges.

OBJECTIVES

To evaluate the effectiveness of pulsed radiofrequency (PRF), thermal radiofrequency (RF) and steroids on dorsal root ganglion (DRG) in patients with thoracic axial pain due to vertebral metastasis.

METHODS

In this randomized controlled prospective study, 140 patients were assessed for eligibility, of which only 69 fulfilled the criteria. Patients were randomly divided into three equal groups, PRF, RF and steroid.

RESULTS

During the assessment of pain using Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), Opioid consumption using oral Morphine Equivalence (OME) and Analgesic Quantification Algorithm (AQA) - at baseline, 1 week, 1 month and 3 months - 81 patients were assessed for final eligibility, of which 12 were excluded before intervention due to drop-out. The remaining 69 were randomized (mean age: 53.87 ± 10.55, 55.78 ± 7.34 and 59.39 ± 13.72) for PRF, RF and steroid, respectively with no statistical difference. VAS% and ODI% decreased significantly at 3 months in RF group (p <0.001, 0.014, respectively), as did the AQA (p <0.027). Steroid group was the worst.

DISCUSSION

RF on DRG is the main stay for controlling intractable metastatic pain. PRF is a good alternative.

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.

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.

Translocation of AMPA Receptors in the Dorsal Horn of the Spinal Cord Corresponding to Long-term Depression Following Pulsed Radiofrequency Stimulation at the Dorsal Root Ganglion

Objective

Pulsed radiofrequency stimulation at the dorsal root ganglion is used for treatment of radicular pain; however, its mechanism for neuropathic pain treatment has not been fully elucidated. Here, we investigated whether pulsed radiofrequency stimulation affects the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, which play a critical role in synaptic plasticity.

Methods

Neuropathic pain was studied using a radicular neuropathic pain model (43 female Sprague-Dawley rats; 200–250 g). In total, 28 rats were assigned to the following groups for fraction analysis: a control group, a control + pulsed radiofrequency stimulation group, a disc pain group, and a disc pain + pulsed radiofrequency stimulation group. For nonfraction analysis of Glutamate A1 (GluA1) and GluA2 subunits, a total of 15 female Sprague-Dawley rats were assigned to a control group, a disc pain group, and a disc pain + pulsed radiofrequency stimulation group. Pulsed radiofrequency stimulation and subsequent analysis were conducted three days after surgery.

Results

AMPA receptor subunits, GluA1 and GluA2, in the radicular neuropathic pain model were upregulated compared with those in the control group three days after surgery. Pulsed radiofrequency stimulation induced the translocation of GluA1 and GluA2 subunits from the synaptosome to cytosol without a change in the total amount of AMPA receptors in the dorsal horn.

Conclusions

Our results demonstrated that pulsed radiofrequency stimulation affected the synaptic plasticity corresponding to long-term depression. Thus, we show that long-term depression from pulsed radiofrequency stimulation is associated with analgesic effects in the radicular neuropathic pain model following peripheral inflammation.

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.

Optimizing the Management and Outcomes of Failed Back Surgery Syndrome: A Proposal of a Standardized Multidisciplinary Team Care Pathway

Failed back surgery syndrome (FBSS) is a major, worldwide health problem that generates considerable expense for healthcare systems. A number of controversial issues concerning the management of FBSS are regularly debated, but no clear consensus has been reached. This pitfall is the result of lack of a standardized care pathway due to insufficient characterization of underlying pathophysiological mechanisms, which are essential to identify in order to offer appropriate treatment, and the paucity of evidence of treatment outcomes. In an attempt to address the challenges and barriers in the clinical management of FBSS, an international panel of physicians with a special interest in FBSS established the Chronic Back and Leg Pain (CBLP) Network with the primary intention to provide recommendations through consensus on how to optimize outcomes. In the first of a series of two papers, a definition of FBSS was delineated with specification of criteria for patient assessment and identification of appropriate evaluation tools in order to choose the right treatment options. In this second paper, we present a proposal of a standardized care pathway aiming to guide clinicians in their decision-making on how to optimize their management of FBSS patients. The utilization of a multidisciplinary approach is emphasized to ensure that care is provided in a uniform manner to reduce variation in practice and improve patient outcomes.

Strategies for interventional therapies in cancer-related pain-a crossroad in cancer pain management

PURPOSE

Interventional therapies are important to consider when facing cancer pain refractory to conventional therapies. The objective of the current review is to introduce these effective strategies into dynamic interdisciplinary pain management, leading to an exhaustive approach to supportive oncology.

METHODS

Critical reflection based on literature analysis and clinical practice.

RESULTS

Interventional therapies act on the nervous system via neuromodulation or surgical approaches, or on primitive or metastatic lesions via interventional radiotherapy, percutaneous ablation, or surgery. Interventional therapies such as neuromodulations are constantly evolving with new technical works still in development. Nowadays, their usage is better defined, depending on clinical situations, and their impact on quality of life is proven. Nevertheless their availability and acceptability still need to be improved. To start with, a patient's interdisciplinary evaluation should cover a wide range of items such as patient's performance and psychological status, ethical considerations, and physiochemical and pharmacological properties of the cerebrospinal fluid for intrathecal neuromodulation. This will help to define the most appropriate strategy. In addition to determining the pros and cons of highly specialized interventional therapies, their relevance should be debated within interdisciplinary teams in order to select the best strategy for the right patient, at the right time.

CONCLUSIONS

Ultimately, the use of the interventional therapies can be limited by the requirement of specific trained healthcare teams and technical support, or the lack of health policies. However, these interventional strategies need to be proposed as soon as possible to each patient requiring them, as they can greatly improve quality of life.

Predictors of the analgesic efficacy of pulsed radiofrequency treatment in patients with chronic lumbosacral radicular pain: a retrospective observational study

Background

Pulsed radiofrequency (RF) targeting the adjacent dorsal root ganglion (DRG) is one treatment option for lumbosacral radicular pain. However, the analgesic efficacy of this procedure is not always guaranteed. The aim of this retrospective study was to identify the predictors of the analgesic efficacy of pulsed DRG RF treatment in patients with chronic lumbosacral radicular pain.

Methods

Patients who underwent pulsed DRG RF treatment from 2006 to 2017 at our clinic were enrolled. Positive response was defined as a ≥50% reduction in pain score from baseline at day 30. Patient demographics, pain-related factors, and clinical factors were evaluated using logistic regression analysis to identify the predictors of a positive response to the treatment.

Results

A total of 60 patients satisfied the study protocol requirements. Twenty-eight patients (46.7%) had a positive outcome. Multivariate logistic regression analysis revealed that the absence of comorbid musculoskeletal pain (OR=0.518, 95% CI=0.029-0.858, P=0.033) and positive response to previous epidural steroid injection (OR=3.269, 95% CI=1.046-10.215, P=0.042) were independent predictors of the analgesic efficacy of pulsed DRG RF treatment.

Conclusion

Comorbid musculoskeletal pain and previous epidural injection response appear to affect the outcome of pulsed DRG RF treatment in patients with chronic lumbosacral radicular pain.