Pulsed radiofrequency neurotomy: advances in pain medicine

Minimally invasive interventional procedures for osteoarthritis and inflammatory arthritis: A systematic review and meta-analysis

OBJECTIVE

to summarize the evidence on the efficacy of minimally invasive interventional procedures such as radiofrequency ablation (RFA) and transcatheter arterial embolization (TAE) in patients with osteoarthritis or inflammatory arthritis.

METHODS

a literature search was conducted in PubMed and Web of Science databases. Both randomized controlled trials (RCTs) and non-randomized studies of interventions (NRSI) were included. The results were organized according to the treated anatomical site: knee, hip, foot and ankle, shoulder, hand and wrist, sacroiliac joints. Data about treatment efficacy were extracted. The main outcome was change in pain intensity using the 0-10 visual analog scale (VAS) from baseline to 1 month. Additional timepoints at 3, 6 and 12 months were assessed. Change in functional status was evaluated. Pooled estimates were calculated as the mean difference (MD) and 95 % confidence interval relative to baseline. The meta-analyses of RCTs and NRSI were conducted separately.

RESULTS

of the 4599 retrieved articles, 164 were included in the review and, considering all the established timepoints, 111 (38 RCTs and 73 NRSI) were selected for the meta-analysis. Only one article described patients with inflammatory arthritis. In the meta-analysis of RCTs, one month after the procedure, MD in VAS was -3.98 (-4.41 to -3.55; k = 21) for knee RFA, and -3.18 (-3.96 to -2.39; k = 8) for sacroiliac joints RFA. In the meta-analysis of NRSI, MD in VAS was -4.12 (-4.63 to -3.61; k = 23) for knee RFA, -3.84 (-4.77 to -2.92; k = 7) for knee TAE, -4.34 (-4.96 to -3.71; k = 2) for hip RFA, -3.83 (-4.52 to -3.15; k = 3) for shoulder RFA and -4.93 (-5.58 to -4.28; k = 14) for sacroiliac joints RFA. Significant decrease in pain intensity was found also at 3, 6 and 12 months. Additionally, functional status improved at all the assessed timepoints.

CONCLUSION

minimally invasive interventional procedures can improve pain and functional status of patients affected by OA or chronic sacroiliac pain of degenerative origin. Further research is warranted in the field of inflammatory rheumatic diseases.

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.

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.

Pulsed Radiofrequency for Post-Covid Occipital Neuralgia: An Effective Therapeutic Proposal - Case Report

With the SARS-CoV-2 pandemic and the increased number of cases reported in the literature of post-Covid syndromes, and clinical conditions of rheumatic and cardiovascular diseases, neurological disorders have also been reported, with the description of cases of reduced memory and cerebrovascular complications post-Covid-19 virus infection. Thus, in addition to these conditions, neuropathic pain secondary to cases of novel coronavirus infection have been seen in the literature and have raised questions about the pathophysiology arising from this situation, prognostic factors, and best indications for treatment. Among the neuropathic pain reported, occipital neuralgia is one of the complications faced, characterized by a burning and paroxysmal pain of variable duration. One of the possible treatments for this condition is the use of pulsed radiofrequency on the affected nerves in cases refractory to optimized clinical treatment, being an effective measure for reducing symptoms and improving quality of life.

Latest Evidence-Based Application for Radiofrequency Neurotomy (LEARN): Best Practice Guidelines from the American Society of Pain and Neuroscience (ASPN)

Radiofrequency neurotomy (RFN), also known as radiofrequency ablation (RFA), is a common interventional procedure used to treat pain from an innervated structure. RFN has historically been used to treat chronic facet-joint mediated pain. The use of RFN has more recently expanded beyond facet-joint mediated pain to peripherally innervated targets. In addition, there has also been the emergence of different radiofrequency modalities, including pulsed and cooled RFN. The use of RFN has been particularly important where conservative and/or surgical measures have failed to provide pain relief. With the emergence of this therapeutic option and its novel applications, the American Society of Pain and Neuroscience (ASPN) identified the need for formal evidence-based guidance. The authors formed a multidisciplinary work group tasked to examine the latest evidence-based medicine for the various applications of RFN, including cervical, thoracic, lumbar spine; posterior sacroiliac joint pain; hip and knee joints; and occipital neuralgia. Best practice guidelines, evidence and consensus grading were provided for each anatomical target.

Pain-Administrable Neuron Electrode with Wireless Energy Transmission: Architecture Design and Prototyping

Back pain resulted from spine disorders reaches 60-80% prevalence in humans, which seriously influences life quality and retards economic production. Conventional electrical pain relief therapy uses radiofrequency to generate a high temperature of 70-85 °C on the electrode tip to destroy the neural transmission and stop the pain. However, due to the larger area of stimulation, eliciting significant side effects, such as paralysis, contraction, and a slightly uncomfortable feeling, our study aimed to design a tiny and stretchable neural stimulatory electrode that could be precisely anchored adjacent to the dorsal root ganglion which needs therapy and properly interfere with the sensory neural transmission. We also designed a subcutaneously implantable wireless power transmission (WPT) device to drive the neural stimulatory electrode. Through the study, we elaborated the design concept and clinical problems, and achieved: (1) the architecture design and simulation of the transdermal wireless power transferred device, (2) a wrap-able pulsed radiofrequency (PRF) stimulatory electrode, (3) an insulation packaging design of the titanium protection box. The feasibility study and hands-on prototype were also carried out.

Clinical observation of CT-guided intra-articular conventional radiofrequency and pulsed radiofrequency in the treatment of chronic sacroiliac joint pain

Background

Sacroiliac joint pain (SIJP) is an important cause of low back pain and seriously affects the patients’ quality of life. Therefore, it is urgent to find effective treatment methods.

Objective

To observe the efficacy of intra-articular (IA) conventional radiofrequency (CRF) and pulsed radiofrequency (PRF) treatment of Sacroiliac joint syndrome (SIJS) under computed tomography (CT) guidance.

Study design

Retrospective comparative study.

Setting

Shengjing Hospital of China Medical University.

Patients and methods

Sixty-four patients with SIJS were enrolled in the Pain management. Patients were randomized into two groups: CRF (CRF group, n=32) and PRF (PRF group, n=32). At each observation time, the general condition, visual analog scale (VAS), the total efficiency rate, Oswestry disability index (ODI), and 36-item short-form health survey were followed up.

Results

Compared to the pretreatment value, the VAS and the ODI decreased in both groups after treatment (P<0.05). In the CRF group, the VAS and the ODI decreased significantly at 1 week after treatment (P<0.05); at 6 and 12 months after treatment, the VAS and the ODI were lower than that in the PRF group (P<0.05). The total efficiency rate in the CRF group and PRF group was 56.3% and 31.3%, respectively (P<0.05). After the relief of pain, both groups received different degrees of improvement in the quality of life. Compared to the pretreatment value, physical component summary (PCS) and the mental component summary (MCS) in both groups were increased after treatment (P<0.05); in the CRF group, PCS and MCS increased significantly at 1 week after treatment (P<0.05); and at 6 and 12 months after treatment, PCS and MCS were higher than those in the PRF group (P<0.05).

Conclusion

CT-guided IA PRF and CRF in the treatment of sacroiliac pain are safe and effective. CRF is superior to PRF in the early and late stage. It is recommended for the treatment of SIJP.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pulsed radiofrequency or anterior neurectomy for anterior cutaneous nerve entrapment syndrome (ACNES) (the PULSE trial): study protocol of a randomized controlled trial

Background

Some patients with chronic abdominal pain suffer from an anterior cutaneous nerve entrapment syndrome (ACNES). This somewhat illusive syndrome is thought to be caused by the entrapment of end branches of the intercostal nerves residing in the abdominal wall. If ACNES is suspected, a local injection of an anesthetic agent may offer relief. If pain is recurrent following multiple-injection therapy, an anterior neurectomy entailing removal of the entrapped nerve endings may be considered. After 1 year, a 70% success rate has been reported. Research on minimally invasive alternative treatments is scarce. Pulsed radiofrequency (PRF) treatment is a relatively new treatment for chronic pain syndromes. An electromagnetic field is applied around the nerve in the hope of leading to pain relief. This randomized controlled trial compares the effect of PRF treatment and neurectomy in patients with ACNES.

Methods

Adult ACNES patients having short-lived success following injections are randomized to PRF or neurectomy. At the 8-week follow-up visit, unsuccessful PRF patients are allowed to cross over to a neurectomy. Primary outcome is pain relief after either therapy. Secondary outcomes include patient satisfaction, quality of life, use of analgesics and unanticipated adverse events. The study is terminated 6 months after receiving the final procedure.

Discussion

Since academic literature on minimally invasive techniques is lacking, well-designed trials are needed to optimize results of treatment for ACNES. This is the first large, randomized controlled, proof-of-concept trial comparing two therapy techniques in ACNES patients. The first patient was included in October 2015. The expected trial deadline is December 2017. If effective, PRF may be incorporated into the ACNES treatment algorithm, thus minimizing the number of patients requiring surgery.

Trial registration

Nederlands Trial Register (Dutch Trial Register), NTR5131 (http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5131). Registered on 15 April 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2110-5) contains supplementary material, which is available to authorized users.

Modulation of serum BDNF levels in postherpetic neuralgia following pulsed radiofrequency of intercostal nerve and pregabalin

Aim: To study the modulation of serum BDNF levels following integrated multimodal intervention in postherpetic neuralgia (PHN). Materials & methods: A randomized, double-blind controlled study was undertaken among patients of thoracic PHN where 30 patients received pregabalin with pulsed radiofrequency and 30 controls received pregabalin with sham treatment. Results: Pain intensity (visual analog scale) was reduced earlier in intervention group (15.3 ± 5.7 at the fourth week) compared with control group (16.3 ± 6.6 at the eighth week). Serum BDNF level increased with time in both the groups with overall increase more pronounced in intervention group. Conclusion: Integrated multimodal therapy using minimally invasive pulsed radiofrequency and pregabalin in PHN was effective in early pain reduction with elevated serum BDNF levels.

Comparative efficacy of stellate ganglion block with bupivacaine vs pulsed radiofrequency in a patient with refractory ventricular arrhythmias

There is increasing interest in interventional therapies targeting the cardiac sympathetic nervous system to suppress ventricular arrhythmias. In this case report, we describe an 80-year-old patient with ischemic cardiomyopathy and multiple implantable cardioverter-defibrillator shocks due to refractory ventricular tachycardia and ventricular fibrillation who was unable to continue biweekly stellate ganglion block procedures using bupivacaine 0.25% for suppression of his arrhythmias. He had previously failed antiarrhythmic drug therapy with amiodarone, catheter ablation, and attempted surgical autonomic denervation. He underwent pulsed radiofrequency treatment (3 lesions, 2 minutes each, temperature 42°C, 2-Hz frequency, 20-millisecond pulse width) of the left stellate ganglion resulting in persistent arrhythmia suppression for more than 12 months duration. This represents the first report of a pulsed radiofrequency stellate ganglion lesion providing long-term suppression of ventricular arrhythmias. Further study of this technique in patients with refractory ventricular tachycardia or ventricular fibrillation is warranted.

Radiofrequency ablation near the bone-muscle interface alters soft tissue lesion dimensions

BACKGROUND AND OBJECTIVES

Radiofrequency (RF) lesions are safe and effective in the treatment of spine pain; however, models developed to study factors affecting lesion dimensions have been performed in homogeneous media that may not accurately simulate human anatomy and electrophysiology. We present a novel ex vivo porcine model for performing RF lesion studies and report the influence of bone on projection of RF ablation lesions into soft tissue.

METHODS

Radiofrequency lesions were performed in porcine rib specimens using monopolar 18-gauge, 10-mm straight active tip cannula, with a lesion temperature of 80°C for 150 seconds. Ten lesions were performed in pure porcine muscle tissue and abutting porcine rib bone with surrounding muscle. Lesions were exposed with dissection and measured with digital calipers.

RESULTS

Maximal effective lesion radius approximately doubled against the bone compared with the pure muscle group (mean, 5.65 mm [95% CI, 5.43-5.87 mm] vs 2.68 mm [95% CI, 2.55-2.81 mm], P < .0001), although this was seen only in a vertical direction and not horizontally. In addition, the prelesion and postlesion impedance of the bone-muscle interface was consistently higher than the muscle-only interface (mean, 165.6 Ohm [95% CI, 146.6-184.6 Ohm] vs 137.8 Ohm [95% CI, 135.5-140.1 Ohm], P = 0.004; 144.3 Ohm [95% CI, 134.3-154.3 Ohm] vs 124.3 Ohm [95% CI, 119.3-129.3 Ohm], P = 0.001). Other dimensions and estimated volume were not significantly different.

CONCLUSIONS

Bone adjacent to RF lesions alters the surrounding electrophysiological environment causing RF lesions to project further perpendicularly from the needle axis, vertically to bone, than previously expected. This phenomenon should be considered in the future modeling and clinical practice of RF.

Combination of diagnostic medial calcaneal nerve block followed by pulsed radiofrequency for plantar fascitis pain: A new modality

Plantar fasciitis (PF) is the most common cause of chronic heel pain which may be bilateral in 20 to 30% of patients. It is a very painful and disabling condition which can affect the quality of life. The management includes both pharmacological and operative procedures with no single proven effective treatment modality. In the present case series, we managed three patients with PF (one with bilateral PF). Following a diagnostic medial calcaneal nerve (MCN) block at its origin, we observed reduction in verbal numerical rating scale (VNRS) in all the three patients. Two patients has relapse of PF pain which was managed with MCN block followed with pulsed radio frequency (PRF). All the patients were pain-free at the time of reporting. This case series highlights the possible role of combination of diagnostic MCN block near its origin followed with PRF as a new modality in management of patients with PF.

[Joint and sensory branch block of the obturator and femoral nerves in a case of femoral head osteonecrosis and arthritis]

The sensory innervation of the hip joint is complex. The joint and sensory branch block of the obturator and femoral nerves is effective for treating the pain caused due to different hip diseases. This could be an option to be considered in certain circumstances such as, being a surgical-anaesthetic high risk, or if there is significant overweight, It could also be useful on other occasions if the traumatoligist considers that it is better to delay hip replacement for a limited period.

Assessing the effectiveness of 'pulse radiofrequency treatment of dorsal root ganglion' in patients with chronic lumbar radicular pain: study protocol for a randomized control trial

Background

Chronic lumbar radicular pain can be described as neuropathic pain along the distribution of a particular nerve root. The dorsal root ganglion has been implicated in its pathogenesis by giving rise to abnormal impulse generation as a result of irritation, direct compression and sensitization. Chronic lumbar radicular pain is commonly treated with medications, physiotherapy and epidural steroid injections. Epidural steroid injections are associated with several common and rarer side effects such as spinal cord infarction and death. It is essential and advantageous to look for alternate interventions which could be effective with fewer side effects.

Pulse radio frequency is a relatively new technique and is less destructive then conventional radiofrequency. Safety and effectiveness of pulse radio frequency in neuropathic pain has been demonstrated in animal and humans studies. Although its effects on dorsal root ganglion have been studied in animals there is only one randomized control trial in literature demonstrating its effectiveness in cervical radicular pain and none in lumbar radicular pain. Our primary objective is to study the feasibility of a larger trial in terms of recruitment and methodology. Secondary objectives are to compare the treatment effects and side effects.

Methods/designs

This is a single-center, parallel, placebo-controlled, triple-blinded (patients, care-givers, and outcome assessors), randomized control trial. Participants will have a history of chronic lumbar radicular pain for at least 4 months in duration. Once randomized, all patients will have an intervention involving fluoroscopy guided needle placement to appropriate dorsal root ganglion. After test stimulation in both groups; the study group will have a pulse radio frequency treatment at 42°C for 120 s to the dorsal root ganglion, with the control group having only low intensity test stimulation for the same duration. Primary outcome is to recruit at least four patients every month with 80% of eligible patients being recruited. Secondary outcomes would be to assess success of intervention through change in the visual analogue scale measured at 4 weeks post intervention and side effects. Allocation to each group will be a 1:1 ratio with allocation block sizes of 2, 4, and 6.

Trial registration

ClinicalTrials.gov NCT01117870

Pulsed radiofrequency treatment in interventional pain management: mechanisms and potential indications-a review

Background

The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF) treatment in chronic pain management in randomized clinical trials (RCTs) and well-designed observational studies. The physics, mechanisms of action, and biological effects are discussed to provide the scientific basis for this promising modality.

Methods

We systematically searched for clinical studies on PRF. We searched the MEDLINE (PubMed) and EMBASE database, using the free text terms: pulsed radiofrequency, radio frequency, radiation, isothermal radiofrequency, and combination of these. We classified the information in two tables, one focusing only on RCTs, and another, containing prospective studies. Date of last electronic search was 30 May 2010. The methodological quality of the presented reports was scored using the original criteria proposed by Jadad et al.

Findings

We found six RCTs that evaluated the efficacy of PRF, one against corticosteroid injection, one against sham intervention, and the rest against conventional RF thermocoagulation. Two trials were conducted in patients with lower back pain due to lumbar zygapophyseal joint pain, one in cervical radicular pain, one in lumbosacral radicular pain, one in trigeminal neuralgia, and another in chronic shoulder pain.

Conclusion

From the available evidence, the use of PRF to the dorsal root ganglion in cervical radicular pain is compelling. With regards to its lumbosacral counterpart, the use of PRF cannot be similarly advocated in view of the methodological quality of the included study. PRF application to the supracapular nerve was found to be as efficacious as intra-articular corticosteroid in patients with chronic shoulder pain. The use of PRF in lumbar facet arthropathy and trigeminal neuralgia was found to be less effective than conventional RF thermocoagulation techniques.

The role of radiofrequency ablation for sacroiliac joint pain: a meta-analysis

Radiofrequency ablation (RFA) has become an option for those with chronic or refractory sacroiliac (SI) joint pain. The purpose of this critical review is to assess the existing literature and conduct a meta-analysis to assess the effectiveness of RFA of the SI joint for pain relief at 3 and 6 months' after an RFA procedure. An electronic search of PubMed, OVID, Medline, and CINAHL were conducted with keywords; sacroiliac joint, sacroiliac pain, sacroiliac syndrome, sacroiliac radiofrequency ablation, sacroiliac neurolysis, sacroiliac injection, and low back pain. Articles that addressed RFA of the SI joint were reviewed. Ten articles ranging from inception to January 1, 2010, were found. The main outcome measure was a reduction of pain by ≥50% post-RFA procedure. At 3 months, 7 groups met the criteria and at 6 months, 6 groups met the criteria. A meta-analysis with a forest plot was done at the 3- and 6-month patient follow-up intervals. The associated standard error was calculated for each study group. An overall weighted average with respective standard error was also obtained. A calculation of 95% confidence intervals (95% CI) was then derived. A test for heterogeneity, publication bias, and file drawer effect was also done at the 3- and 6-month intervals. At 3 months, a range of 0.538-0.693 was found to have a 95% CI, with a pooled mean of 0.616. At 6 months, a 95% CI of 0.423-0.576 was found, with a pooled mean of 0.499. The meta-analysis demonstrated that RFA is an effective treatment for SI joint pain at 3 months and 6 months. This study is limited by the available literature and lack of randomized controlled trials. Further standardization of RFA lesion techniques needs to be established, coupled with prospective randomized controlled trials.

Pulsed radiofrequency for chronic pain

Pulsed radiofrequency (PRF), a technology related to continuous radiofrequency, is unique in that it provides pain relief without causing significant damage to nervous tissue. The mechanism by which PRF controls pain is unclear, but it may involve a temperature-independent pathway mediated by a rapidly changing electrical field. Although much anecdotal evidence exists in favor of PRF, there are few quality studies substantiating its utility.

Pulsed radiofrequency: a critical review of its efficacy

Pulsed radiofrequency is a growingly popular pain treatment modality. However, its clinical efficacy remains controversial. In this review, the available literature on pulsed radiofrequency is critically analysed to determine its clinical efficacy. Our search of the literature for pulsed radiofrequency yielded 341 citations; after reviewing the abstracts we found 51 relevant articles. There were 4 review articles: 44 articles pertained to the application of pulsed radiofrequency by an electrode placed in the vicinity of a neural structure. Of these only two were randomised controlled trials. Of the remaining 42 articles, one was a non-randomised controlled trial, three were prospective uncontrolled trials: there were six retrospective studies, 11 case reports, eight laboratory studies, two position papers, five editorials and seven items of correspondence, while one publication reported two studies. Three articles pertained to transcutaneous application of pulsed radiofrequency. Of the two randomised controlled trials, one reported efficacy of the pulsed radiofrequency while the other reported it to be ineffective. The majority of the uncontrolled and observational studies reported clinical efficacy of pulsed radiofrequency, however many of these studies had limitations. Further randomised controlled clinical trials are recommended in order for the practising pain physician to clearly understand the role of pulsed radiofrequency in the treatment of various chronic pain syndromes.

Sacroiliac joint pain: anatomy, biomechanics, diagnosis, and treatment

The sacroiliac joint is an underappreciated cause of low back and buttock pain. It is thought to cause at least 15% of low back pain. It is more common in the presence of trauma, pregnancy, or in certain athletes. The pelvic anatomy is complex, with the joint space being variable and irregular. The joint transmits vertical forces from the spine to the lower extremities and has a role in lumbopelvic dynamic motion. History and physical examination findings can be helpful in screening for sacroiliac joint pain, but individual provocative maneuvers have unproven validity. Fluoroscopically guided injections into the joint have been found to be helpful for diagnostic and therapeutic purposes. Conservative treatment, which also can include joint mobilization, antiinflammatory medicines, and sacroiliac joint belts, generally is effective. Surgical arthrodesis should be considered a procedure of last resort.

Pulsed radiofrequency: current clinical and biological literature available

OBJECTIVE

Pulsed radiofrequency, where short bursts of radiofrequency energy are applied to nervous tissue, has been used by pain practitioners as a non- or minimally neurodestructive technique, alternative to radiofrequency heat lesions. Clinical advantages and mechanisms of this treatment remain unclear. The objective of this study was to review current clinical and laboratory data.

DESIGN

We systematically searched the MEDLINE database (PubMed) and tables of contents of electronically available pain journals. Reference lists of relevant reports and international scientific pain congress abstract books were also hand searched. Only those reports on pulsed radiofrequency were withheld.

RESULTS

The final analysis yielded 58 reports on the clinical use of pulsed radiofrequency in different applications: 33 full publications and 25 abstracts. We also retrieved six basic science reports, five full publications, and one abstract.

CONCLUSIONS

The accumulation of these data shows that the use of pulsed radiofrequency generates an increasing interest of pain physicians for the management of a variety of pain syndromes. Although the mechanism of action has not been completely elucidated, laboratory reports suggest a genuine neurobiological phenomenon altering the pain signaling, which some have described as neuromodulatory. No side effects related to the pulsed radiofrequency technique were reported to date. Further research in the clinical and biological effects is justified.

Interventional pain management: when/what therapies are best for low back pain

PURPOSE OF REVIEW

The aim of this article is to inform an interested audience on novel minimally invasive and percutaneous interventional options for reduction of lower back pain.

RECENT FINDINGS

Numerous percutaneous and minimally invasive techniques for treatment of lower back pain were introduced recently. To accumulate sufficient clinical evidence in order to either dismiss or accept the new treatment modalities requires years of delay. Presented here are novel percutaneous procedures to treat discogenic pain, radiculopathies, lumbar facet syndrome, painful compressive vertebral fractures, myofascial pain and postlaminectomy syndrome. Data on efficacy of those procedures available from limited case series reports, retrospective studies and a few prospective trials are reviewed.

SUMMARY

There is a wide variety of techniques introduced recently in pain management of the lower back. Some of those procedures may serve as a definite treatment; others may significantly enhance or facilitate conservative management. Careful selection of the patients may significantly improve the success rates of these procedures.

Interventional spine procedures

Minimally invasive techniques for the treatment of some spinal diseases are percutaneous treatments, proposed before classic surgery. By using imaging guidance, one can significantly increase accuracy and decrease complication rates. This review report physiopathology and discusses indications, methods, complications and results of performing these techniques on the spine, including different level (cervical, thoracic, lumbar and sacroiliac) and different kind of treatments (nerve block, disc treatment and bone treatment). Finally the present article also reviews current literature on the controversial issues involved.

Interventional modalities in the treatment of complex regional pain syndrome

Complex regional pain syndrome (CRPS) applies to a variety of conditions in which symptoms such as allodynia and hyperalgesia predominate along with hyperpathia and vasomotor/sudomotor disturbances. The incidence of CRPS in the chronic pain population varies and is difficult to determine, though it appears to affect women more than men. Treatment is multidisciplinary, and recovery of function and the reduction of pain are the main goals of treatment;this article addresses some of the interventional modalities that are used.