Pulsed radiofrequency: rebel without cause

Lumbar sympathetic pulsed radiofrequency combined with continuous epidural infusion for treatment of painful diabetic neuropathy: A report of two cases and a literature review

Diabetic neuropathy (DN), one of the most common late complications of diabetes mellitus, significantly affects distinct regions of the nervous system. Pain management is challenging in DN as no effective therapies exist that reverse the pathological course of DN. Several drugs are recommended as the first-line treatment for painful DN, but these are associated with various side-effects in the long term. This report presents two cases with painful DN who underwent lumbar sympathetic pulsed radiofrequency combined with continuous epidural infusion. The two cases were followed for 30 days. Lumbar sympathetic pulsed radiofrequency combined with continuous epidural infusion offered effective pain relief and improved the health-related quality of life in two patients with DN over this time period.

The short term impact of radiofrequency ablative techniques and peripheral nerve block on thermoregulation in mouse models

This study investigated the impact of multiple nerve block methods (local anesthesia, conventional radiofrequency thermocoagulation [CRF], and pulsed radiofrequency [PRF]) on thermoregulation. Focusing on hypothalamic function, the effects of local anesthesia, CRF, and PRF on central and peripheral temperatures were analyzed and compared. Our findings revealed that all three nerve block groups cause a decrease in central temperature, with the CRF group exhibiting the most pronounced effect. Furthermore, immunostaining analysis showed decreased neural activity in the preoptic area, suggesting that nerve blocks may influence central thermoregulatory mechanisms. This study provides valuable insights into the effects of peripheral nerve blocks on thermoregulation and may contribute to the development of therapeutic strategies to managing perioperative hypothermia and enhancing pain management, especially in patients undergoing surgeries with high risks of thermoregulatory complications, such as on-pump surgery and laparoscopic surgery.

Mesenchymal stem cells and thermal annular procedures for discogenic pain: a systematic review with pooled analysis

Aim: Compare the effectiveness of mesenchymal stem cell injection therapies (MSC) and thermal annular procedures for the treatment of discogenic lower back pain. Materials & methods: A systematic review was performed following PRISMA 2020 guidelines. Pooled analysis was performed using patients' pain scores at baseline and at 12 months post-intervention. Results: Effect sizes based on change in pain score from baseline to 12 month follow-up revealed clinically significant improvement in pain score across all interventions. Conclusion: Minimally invasive interventions provide meaningful relief in discogenic back pain, with results suggesting promise for MSC injection therapies as a treatment model.

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.

Ultrasound-guided pulsed radiofrequency of the saphenous nerve for knee osteoarthritis pain: a pilot randomized trial

Aim: Knee osteoarthritis is a degenerative disease complicated by pain and functional limitation. Newer pain-relieving interventions include pulsed radiofrequency (PRF), but studies on its efficacy have limitations including lack of control group and retrospective design that prevent sound conclusions. Materials & methods: We conducted a blind prospective randomized sham-controlled crossover pilot trial according to the CONSORT guidelines, to evaluate the efficacy of ultrasound-guided saphenous nerve PRF in gonarthritis pain. Results: Sixteen patients completed the study. Pain and function significantly improved after real PRF (numerical rating scale mean difference = 3.31), which was superior to sham PRF over time for pain (3 months) and function (6 months). Conclusion: PRF of the saphenous nerve is an alternative to relieve pain in gonarthritis. Our results provide data to support a sample size calculation for future trials. Clinical trial registration: NCT04454710.

Transforaminal Epidural Injection of Local Anesthetic and Dorsal Root Ganglion Pulsed Radiofrequency Treatment in Lumbar Radicular Pain: A Randomized, Triple-Blind, Active-Control Trial

BACKGROUND

Lumbar radicular pain (LRP) results from inflammation and irritation of lumbar spinal nerves and the dorsal root ganglion (DRG).

METHODS

Our study is a prospective, triple-blind, randomized, activecontrol trial (CTRI/2016/02/006666) comparing transforaminal epidural local anesthetic (LA) injection and pulsed radiofrequency treatment of DRG in patients with chronic LRP. Patients with LRP after failed conservative management for >3 months received selective diagnostic nerve root block with 1 mL 2% lidocaine. Fifty patients showing positive responses were divided into groups of 25 each. The LA group received transforaminal epidural injection of 1 mL 0.5% bupivacaine. The lumbar pulsed radiofrequency (LPRF) group received transforaminal epidural injection of 1 mL 0.5% bupivacaine with 3 cycles of pulsed radiofrequency of the DRG for 180 seconds RESULTS: Both groups were compared by observing pain intensity on a 0- to 100-point VAS and improvement in functional status by the Oswestry Disability Index (ODI version 2.0) at 2 weeks and 1, 2, 3, and 6 months. All baseline variables were comparable between the 2 groups. Statistically significant reduction in both outcomes was seen in the LPRF group compared to the LA group from 2 weeks to 6 months. One hundred percent of patients in the LPRF group had a ≥20- point decrease in VAS and significant percentage reduction in ODI at all time intervals up to 6 months, whereas it was seen in 80% and 28% of patients in the LA group at 3 and 6 months, respectively. No complications were seen in any patients CONCLUSION: Pulsed radiofrequency of the DRG applied for longer duration results in long-term pain relief and improvement in the functional quality of life in patients with chronic LRP.

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

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

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

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

Systematic Review of Radiofrequency Ablation for Management of Knee Pain

PURPOSE OF REVIEW

Chronic pain of the lower extremity remains challenging to manage. Radiofrequency ablation procedure applies heat to nerve fibers with the goal of mitigating chronic pain conditions of the knee. However, the clinical efficacy has not yet been adequately established. The goal of this review paper is to report the use of radiofrequency ablations in the treatment of osteoarthritis of the knee.

RECENT FINDINGS

PubMed and the Cochrane Controlled Trials Register were searched (final search 28 February 2018) using the MeSH terms "radiofrequency ablation," "neurolysis," "radiofrequency therapy," "pain syndrome," "analgesia," and "pain" in the English literature. Bibliographies of the published papers were screened for relevance to lower extremity radiofrequency ablation therapies. The quality of selected publications was assessed using the Cochrane risk of bias instrument. Of the 923 papers screened, 317 were further investigated for relevance. Our final search methodology yielded 19 studies that investigated the use of radiofrequency ablation at the knee. Of these 19 studies, there were four randomized control trials, two non-randomized control trials, three prospective studies, two retrospective studies, one case-control study, one technical report, and seven case reports. In summary, the data available suggests radiofrequency ablation as a promising and efficacious with all 19 studies revealing significant short- and long-term pain reductions in patients with knee pain.

A Systematic Review of Radiofrequency Treatment of the Ankle for the Management of Chronic Foot and Ankle Pain

BACKGROUND

Chronic pain of the lower extremity remains challenging to manage. Radiofrequency treatment applies heat to nerve fibers with the goal of mitigating chronic pain conditions. The clinical efficacy has not yet been adequately established for pathologies of the ankle and foot. In this review paper, we report the use and efficacy of radiofrequency treatment applied to foot and ankle pain.

RECENT FINDINGS

PubMed and the Cochrane Controlled Trials Register were searched (final search 30 March 2018) using the MeSH terms "radiofrequency ablation," "neurolysis," "radiofrequency therapy," "pain syndrome," "analgesia," "plantar heel pain," "plantar fascitis," and "chronic pain" in the English literature. Of the 23 papers screened, 18 were further investigated for relevance. Our final search methodology yielded 15 studies that investigated the use of radiofrequency treatment at the ankle. Of these 15 studies, there were three randomized control trials, four prospective studies, three retrospective studies, and five case reports. The quality of selected publications was assessed using the Cochrane risk of bias instrument. The evidence from our studies suggests that radiofrequency treatment can be used safely for the management foot and ankle pain. The technique (continuous vs pulsatile), temperature, location of treatment, and duration of administration need more thorough evaluation. Randomized control trials are needed to establish the efficacy and safety profile of radiofrequency ablation and its long-term benefits in patients with chronic pain of the foot and ankle.

CONCLUSION

The evidence from our studies suggests that radiofrequency treatment can be used safely for the management foot and ankle pain. The technique (continuous vs pulsatile), temperature, location of treatment, and duration of administration need more thorough evaluation. Randomized control trials are needed to establish the efficacy and safety profile of radiofrequency ablation and its long-term benefits in patients with chronic pain of the foot and ankle.

Lumbar Sympathetic Pulsed Radiofrequency Treatment for Primary Erythromelalgia: A Case Report

Erythromelalgia is often refractory and resistant to many forms of treatment. Numerous therapeutic options have been tried, but effective treatment remains elusive. The sympathetic nervous system has been involved in various painful conditions of neuropathic, vascular, and visceral origin. Sympathetic block is helpful in making a diagnosis and managing pain. We report a case of excellent pain relief after lumbar sympathetic pulsed radiofrequency treatment in a patient with primary erythromelalgia of the lower extremities. This case suggests the viability of pulsed radiofrequency treatment in patients with erythromelalgia.

Ultra-extended euthermic pulsed radiofrequency for the treatment of ophthalmic neuralgia: A case report with elaboration of a new technique

BACKGROUND

Pulsed radiofrequency although present for many years has been used little compared to ablative procedures for pain relief. Its use in trigeminal neuralgia is sparse and unreported in the ophthalmic division, where the possibility of sensory loss can lead to high morbidity. We wished to explore the potential of this reportedly safe modality for a prolonged duration in a highly sensitive anatomic neural location, however, in a very secure, structured, and staged manner.

CASE DESCRIPTION

A patient suffering from ophthalmic division (V1) medically uncontrolled neuralgia with a preoperative visual analog scale (VAS) score of 9/10 was subjected to a percutaneous pain relief procedure. The patient was treated with prolonged duration pulsed radiofrequency (PRF) for 40 min, with corneal sensation monitoring under conscious sedation keeping a low voltage (7 V) and tip temperature at 37°C. The patient obtained immediate relief, which was verified on the operation table itself. Postoperative VAS score of 0/10 was recorded. More than 6 months after the procedure, the patient is completely free from neuralgic pain and continues to have a VAS score of 0/10.

CONCLUSION

As opposed to conventional PRF where mostly a tip temperature of 42°C and high voltage have been used for 2 to a maximum of 8 min, PRF with a tip temperature of 37°C and a safe voltage of 7 V over an ultra-extended duration of 40 min can give a more distinct and effective but equally safe result. Although our case verified the safety and efficacy of prolonged duration PRF in sensitive anatomic locations, more studies are warranted for establishing this as a standard line of treatment. The specific use of PRF in ophthalmic division neuralgia in the manner described in our case report has hitherto not been reported in medical literature and will open a new vista in the minimally invasive treatment of this disease.

One-year follow-up results of intradiscal diode laser, radiofrequency, and pulsed radiofrequency therapies: a retrospective study

This study aims to investigate the efficacy of three different percutaneous intradiscal therapies in patients with chronic low back pain (CLBP) due to lumbar disc herniation (LDH). Medical files of a total of 120 patients who received percutaneous intradiscal therapy were retrospectively analyzed. All patients were divided into three groups: group L: diode laser (n = 40), group R: radiofrequency (RF) (n = 40), and group P: pulsed radiofrequency (PRF) (n = 40). The visual analogue scale (VAS) and Oswestry Disability Index (ODI) scores were calculated at 1, 3, 6, and 12 months for all patients. One-year follow-up results were as follows: group L: pre-treatment (PreT) VAS 5.6 ± -1, ODI 37.6 ± -4.7, post-treatment 12th month (PT12) VAS 2.8 ± -1.4, ODI 14.1 ± -7.1; group P: PreT VAS 6.0 ± 1, ODI 37.5 ± 5.9, PT12 VAS 3.1 ± 1.3, ODI 20.3 ± 17.0; and group R: PreT VAS 5.6 ± 1.0, ODI 37.9 ± 4.7, PT12 VAS 3.3 ± 1.4, ODI 27.2 ± 14.1. In each of the three groups, there was a statistically significant reduction in the VAS and ODI scores at 1, 3, 6, and 12 months, compared to the baseline values (p < 0.05). The highest reduction in the VAS and ODI scores was observed in group L, whereas the lowest reduction was in group R. We consider that in groups with patient selection criteria at our study; diode laser, RF, and PRF, which are administered using the percutaneous intradiscal route for CLBP patients diagnosed with LDH, may be used as an alternative treatment option.

Pulsed radiofrequency in clinical practice - A retrospective analysis of 238 patients with chronic non-cancer pain treated at an academic tertiary pain centre

BACKGROUND AND AIMS

Pulsed radiofrequency is a non-neurodestructive invasive pain treatment which, in contrast to conventional continuous radiofrequency treatment, does not entail nerve tissue destruction. The aim of this study was to retrospectively analyse the short-term benefits of a broad use of pulsed radiofrequency in clinical practice.

METHODS

The medical records of all patients treated with pulsed radiofrequency, or who received a diagnostic test block with a local anaesthetic in view of such a treatment, were retrospectively analysed. The patients had been referred to a tertiary pain centre in Sweden. The treatment effect one month after pulsed radiofrequency was retrospectively graded as follows, based on the wordings of the medical records: major improvement; minor improvement; no change; or worsened.

RESULTS

A total of 238 patients received 587 interventions from 2009 to 2014. Chronic low back pain (CLBP) was by far the most common treatment indication (57% of patients), followed by CLBP with sciatica (9%). The age at first pulsed radiofrequency was 55 (15-94) years (mean, range), and 65% were female. Thirty-six patients (15%) underwent only a diagnostic test block using a local anaesthetic, i.e., the test block did not lead to treatment with pulsed radiofrequency. A total of 445 pulsed radiofrequency interventions were performed on 202 patients. Dichotomizing data into responders (i.e., minor or major improvement) and non-responders (i.e., worsened or no change), we found that, out of 63 responders to a median branch diagnostic test block (either at the cervical or lumbar level), 33 were responders to the first following median branch pulsed radiofrequency. Hence the positive predictive value of a median branch test block was 52%. In 127 patients, the lumbar level was targeted for median branch pulsed radiofrequency because of clinically suspected lumbar facetogenic pain. Looking at the first treatment, 30% experienced major improvement after 1 month, 16% minor improvement, 36% no change, 5% a worsened situation, and the effect was not assessable in 13% of patients. Lone dorsal root ganglion L2-treatment for suspected discogenic lumbar pain was done on 39 patients and, after one month, the effect was not assessable in 17% of patients, 14% had major improvement, 14% minor improvement, and 55% had no change. In 40 patients, a dorsal root ganglion or a peripheral nerve was targeted because of a non-axial chronic pain condition. There was a plethora of indications, but the most common was by far related to some form of neuropathic pain (52% of interventions, mainly because of neuralgia), followed by chronic nociceptive shoulder pain (8% of interventions).

CONCLUSIONS

This study shows that, after one month, the effect size of a broad and indiscriminate clinical use of pulsed radiofrequency is rather small.

IMPLICATIONS

The clinical effectiveness of pulsed radiofrequency has to be investigated further in carefully selected and more homogenous patient groups, in order to define effective treatment niches for this nondestructive invasive treatment method.

Continuous Thoracic Sympathetic Ganglion Block in Complex Regional Pain Syndrome Patients with Spinal Cord Stimulation Implantation

The sympathetic block is widely used for treating neuropathic pain such as complex regional pain syndrome (CRPS). However, single sympathetic block often provides only short-term effect. Moreover, frequent procedures for sympathetic block may increase the risk of complications. The use of epidural route may be limited by concern of infection in case of previous implantation of the spinal cord stimulation (SCS). In contrast, a continuous sympathetic block can be administered without such concerns. The continuous thoracic sympathetic block (TSGB) has been used to treat the ischemic disease and other neuropathic conditions such as postherpetic neuralgia. We administered continuous thoracic sympathetic block using catheter in CRPS patients who underwent SCS implantations and achieved desirable outcomes. We believe a continuous sympathetic block is a considerable option before performing neurolysis or radiofrequency rhizotomy and even after SCS implantation.

Effect of pulsed radiofrequency in treatment of facet-joint origin back pain in patients with degenerative spondylolisthesis

BACKGROUND

Degenerative spondylolisthesis is a well-recognized source of low back pain mainly induced by facet joint pain. Pulsed radiofrequency (PRF) allows heat dissipation, thus producing a temporary injury that affects only type C fibers responsible for pain conduction.

OBJECTIVES

We attempted to test whether PRF is a better choice for facet pain due to spondylolisthesis compared to routine steroid injection.

METHODS

Patients were randomly assigned to one of two groups: group one received pulsed RF, and group 2 received injection by steroids (triamcinolone) and bupivacaine.

OUTCOMES ASSESSMENT

Multiple outcome measures were utilized which included the numeric rating scale (NRS), the Oswestry Disability Index (ODI), satisfaction status, and analgesic intake with assessment at 3, 6, and 12 months post-treatment. Significant pain relief was defined as 50% or more, whereas significant improvement in disability score was defined as reduction of 40% or more.

RESULTS

Eighty patients were enrolled in the study and were divided into the two groups of study. PRF significantly reduced NRS at 6-month follow-up compared to steroid + bupivacaine. 75.6 ± 14.3% at pre-treatment and 19.3 ± 9.5% at 6 months (p = 0.001) in PRF group. The mean ODI is depicted in two groups of study (Fig. 1). Interestingly, ODI% was significantly lower in PRF group at 12 weeks and 6 months compare to steroid + bupivacaine group (p = 0.022 and 0.03, respectively), but it was not significantly different at 6 weeks (p = 0.31). Proportion of patients who did not require analgesics were significantly higher in PRF group compared to other group (p = 0.001) in Log-rank (Mantel-Cox) test.

CONCLUSION

Our results demonstrated that the application of PRF might be more effective than steroid and bupivacaine injection in decreasing back pain due to degenerative facet pain and improvement in function of patients.

Pulsed radiofrequency treatment of the lumbar dorsal root ganglion in patients with chronic lumbar radicular pain: a randomized, placebo-controlled pilot study

Background

No proof of efficacy, in the form of a randomized controlled trial (RCT), exists to support pulsed radiofrequency (PRF) treatment of the dorsal root ganglion (DRG) for chronic lumbar radicular (CLR) pain. We determined the feasibility of a larger trial (primary objective), and also explored the efficacy of PRF in decreasing pain on a visual analog scale (VAS) and improving the Oswestry Disability Index.

Methods

This was a single-center, placebo-controlled, triple-blinded RCT. Patients were randomized to a placebo group (needle placement) or a treatment group (PRF at 42°C for 120 seconds to the DRG). Patients were followed up for 3 months post procedure. Outcomes with regard to pain, Oswestry Disability Index score, and side effects were analyzed on an intention-to-treat basis.

Results

Over 15 months, 350 potential patients were identified and 56 were assessed for eligibility. Fifteen of them did not meet the selection criteria. Of the 41 eligible patients, 32 (78%) were recruited. One patient opted out before intervention. Three patients were lost to follow-up at 3 months. Mean VAS differences were not significantly different at 4 weeks (−0.36, 95% confidence interval [CI], −2.29, 1.57) or at 3 months (−0.76, 95% CI, −3.14, 1.61). The difference in mean Oswestry Disability Index score was also not significantly different at 4 weeks (−2%, 95% CI, −14%, 10%) or 3 months (−7%, 95% CI, −21%, 6%). There were no major side effects. Six of 16 patients in the PRF group and three of 15 in the placebo group showed a >50% decrease in VAS score.

Conclusion

The recruitment rate was partially successful. At 3 months, the relative success of PRF-DRG was small. A large-scale trial to establish efficacy is not practically feasible considering the small effect size, which would necessitate recruitment of a challengingly large number of participants over a number of years. Until clear parameters for application of PRF are established, clinicians will need to use their individual judgment regarding its clinical applicability, given the present evidence.

Ultrasound-assisted mental nerve block and pulsed radiofrequency treatment for intractable postherpetic neuralgia: three case studies

Postherpetic neuralgia (PHN) is one of the most difficult pain syndromes to treat. Invasive treatments may be considered when patients fail to obtain adequate pain relief from noninvasive treatment approaches. Here, we present three cases of PHN in the mandibular branch treated with ultrasound-assisted mental nerve block and pulsed radiofrequency treatment. None of the patients had adequate pain relief from the medical therapy, so we performed the mental nerve block on the affected side under ultrasound assistance. Two patients showed satisfactory pain relief continuously over 12 months without any further interventions, whereas one patient only had short-term pain relief. For the patient had short-term pain relief we performed pulsed radiofrequency treatment (PRFT) on the left mental nerve under ultrasound assistance. After PRFT, the patient had adequate pain relief for 6 months and there was no need for further management.

Ultrasound-guided Pulsed Radiofrequency of the Third Occipital Nerve

A C2-3 zygapophygeal joint is a major source of cervicogenic headache. Radiofrequency (RF) neurotomy is preformed widely for zygapophygeal joint pain. Conventional RF denervation technique is generally performed under fluoroscopic control. Recently, ultrasound-guided radiofrequency on zygapophygeal joint has emerged as an alternative method. We report our experiences of two successful ultrasound-guided pulsed radiofrequencies on 39-year-old and 42-year-old males, who complained occipital headache and posterior neck pain.

Pulsed radiofrequency treatment for idiopathic trigeminal neuralgia: a retrospective analysis of the causes for ineffective pain relief

We retrospectively analyzed the reasons for ineffective pain relief in patients with idiopathic trigeminal neuralgia (TN) who had undergone pulsed radiofrequency (PRF) treatment guided by computed tomography scan. We found that intraoperative PRF output voltage and electrical field intensity was significantly higher (p < 0.05) in the group who had received effective treatment than in the ineffective group. These findings suggest that optimizing PRF parameters and increasing the intraoperative output voltage (electric field intensity) may therefore, provide better pain relief in patients with TN.

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

Treatment of meralgia paresthetica with ultrasound-guided pulsed radiofrequency ablation of the lateral femoral cutaneous nerve

A 23-year-old female with an 18-month history of left anterolateral thigh paresthesias and burning pain consistent with meralgia paresthetica was referred to our clinic after failing trials of physical therapy, nonsteroidal anti-inflammatories, gabapentin, and amitriptyline. We performed 3 lateral femoral cutaneous nerve blocks with corticosteroid over a 4-month period; however, each block provided only temporary relief. As this pain was limiting the patient's ability to perform her functions as an active duty service member, we elected to perform a pulsed radiofrequency treatment of the lateral femoral cutaneous nerve with ultrasound guidance and nerve stimulation. After locating the lateral femoral cutaneous nerve with ultrasound and reproducing the patient's dysthesia with stimulation, pulsed radiofrequency treatment was performed at 42°C for 120 seconds. The needle was then rotated 180° and an additional cycle of pulsed radiofrequency treatment was performed followed by injection of 0.25% ropivacaine with 4 mg of dexamethasone. At 1.5 and 3 month follow-up visits, the patient reported excellent pain relief with activity and improved ability to perform her duties as an active duty service member. ▪

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.