Pulsed Radiofrequency Ablation for Residual and Phantom Limb Pain: A Case Series

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.

Pulsed Radiofrequency for Auriculotemporal Neuralgia: A Case Report

Auriculotemporal neuralgia is a rare facial pain disorder with no therapeutic evidence for refractory cases. We described a male patient with right auriculotemporal neuralgia, refractory to anesthetic nerve blocks and botulinum toxin type A injections, who was successfully treated with pulsed radiofrequency without adverse events. Pulsed radiofrequency may be an effective and safe treatment for refractory auriculotemporal neuralgia.

Targeted muscle reinnervation in managing post-amputation related pain: A systematic review and meta-analysis

INTRODUCTION

Limb amputation can cause residual limb pain (RLP) and/or phantom limb pain (PLP). Although targeted muscle reinnervation (TMR) was initially introduced to facilitate the control of prosthetic limbs, it has been noted that these patients experience less pain and improved prosthetic functional outcomes. As a result, the use of TMR in managing neuroma-related RLP is increasing. The aim of this review is to assess the quality and strength of the evidence supporting the effectiveness of TMR in managing amputation-related pain.

METHODS

Five different databases, including MEDLINE (PubMed), Scopus, Web of Science, Cochrane Library, and Embase, were searched from inception to March 2022. The protocol for this systematic review has been registered in the PROSPERO database (CRD42020218242). To be included, studies needed to compare pre- and postoperative pain outcomes or different techniques for adult patients who underwent TMR following amputation. Eligible studies also needed to use patient-reported outcome measures (PROMS) and be clinical trials or observational studies published in English. Excluded studies were case reports, case series, reviews, proof of concept studies, and conference proceedings. A meta-analysis was performed on studies that had similar intervention and control groups to examine treatment effects using a random-effects model. Studies were weighted using the inverse variance method, and a statistically significant p-value was considered to be less than or equal to 0.05.

RESULTS

This review included five studies for qualitative analysis and four studies for quantitative analysis. Reviewed studies enrolled a total of 127 patients. The TMR group was compared with standard treatment at 12 months follow-up. The TMR group showed significantly better PLP as assessed by the numerical rating score RLP, and PLP assessed using Patient-Reported Outcomes Measurement Information System (PROMIS) also showed significantly lower pain intensity in the TMR group.

CONCLUSION

There is limited evidence of good quality favoring TMR in reducing postamputation PLP and RLP pain compared with standard care. Randomized clinical trials are encouraged to compare the efficacy of different surgical techniques.

Case report: A combination of mirror therapy and magnetic stimulation to the sacral plexus relieved phantom limb pain in a patient

Phantom limb pain (PLP) is a common sequela of amputation, experienced by 50-80% of amputees. Oral analgesics as the first-line therapy have limited effects. Since PLP usually affects activities of daily living and the psychological conditions of patients, effective treatments are imperatively needed. In this case study, a 49-year-old man was admitted to our hospital because of uncontrollable paroxysmal pain in his missing and residual leg. Due to severe injuries in a truck accident, the right lower limb of the patient was surgically amputated ~5 years ago. Around 1 month after amputation, he felt pain in his lost leg and PLP was diagnosed. Then, he started taking oral analgesics, but the pain still occurred. After admission on July 9, 2022, the patient received treatments of mirror therapy and magnetic stimulation to the sacral plexus. 1-month treatments reduced the frequency and intensity of pain in the phantom limb and the stump, without any adverse events. Analysis of high-resolution three-dimensional T1-weighted brain volume images at the end of 2-month treatments showed alterations in the thickness of cortex regions related to pain processing, compared to that before treatment. This case study gives us hints that one or both interventions of mirror therapy and sacral plexus magnetic stimulation effectively relieved PLP and stump limb pain. These non-invasive, low-cost and easily conducted treatments could be good options for PLP. But randomized controlled trials with a large number of cases are required to confirm their efficacy and safety.

Evolving techniques for reducing phantom limb pain

At least two million people in the United States of America live with lost limbs, and the number is expected to double by 2050, although the incidence of amputations is significantly greater in other parts of the world. Within days to weeks of the amputation, up to 90% of these individuals develop neuropathic pain, presenting as phantom limb pain (PLP). The pain level increases significantly within one year and remains chronic and severe for about 10%. Amputation-induced changes are considered to underlie the causation of PLP. Techniques applied to the central nervous system (CNS) and peripheral nervous system (PNS) are designed to reverse amputation-induced changes, thereby reducing/eliminating PLP. The primary treatment for PLP is the administration of pharmacological agents, some of which are considered but provide no more than short-term pain relief. Alternative techniques are also discussed, which provide only short-term pain relief. Changes induced by various cells and the factors they release are required to change neurons and their environment to reduce/eliminate PLP. It is concluded that novel techniques that utilize autologous platelet-rich plasma (PRP) may provide long-term PLP reduction/elimination.

Percutaneous treatments for residual and/or phantom limb pain in adults with lower-extremity amputations: A narrative review

Residual limb pain (RLP) and phantom limb pain (PLP) profoundly affect the lives of many individuals who have undergone lower- or upper-extremity amputation. Despite the considerable impact of RLP/PLP on quality of life in persons with amputation, there have been few attempts to evaluate the efficacy of percutaneous interventions in the treatment of RLP and/or PLP. This narrative review evaluates the effectiveness of percutaneous treatments for RLP and/or PLP in patients after lower-extremity amputation. Peripheral nerve stimulation, alcohol neurolysis, conventional thermal radiofrequency ablation, perineural corticosteroid injection, botulinum toxin injection, and etanercept injection were associated with varying success rates. Wide confidence intervals and small treatment cohorts impede assessments of overall success. High-quality studies of nonsurgical, percutaneous treatments for RLP and/or PLP are lacking. Well-designed randomized controlled trials and large cohort studies with comparison groups using validated outcomes are needed to determine the effectiveness of nonsurgical interventions for the treatment of RLP and PLP.

A small painful neuroma of the transverse cervical nerve treated with pulsed radiofrequency: A case report

BACKGROUND

Neck pain is a common complaint seen amongst patients from all ages. When common causes of neck pain have been ruled out, it is important to investigate further. A careful physical exam can help identify the painful structures. An ultrasound of the area can also be helpful to identify possible structures involved. Neuromas can be treated with oral medications as well as more invasive techniques, such as pulsed radiofrequency (PRF).

CASE DESCRIPTION

In this case report, we discuss a 67-year-old female who presented with left anterior neck pain after developing a cervical mass who was later diagnosed as non-Hodgkin lymphoma. A small neuroma of the left transverse cervical nerve was found on ultrasound and ultimately was treated with PRF with a complete resolution of her symptoms at two months follow-up.

CONCLUSION

PRF seems to be a useful tool for controlling neuropathic pain caused by a neuroma.

An Algorithm Approach to Phantom Limb Pain

Phantom limb pain (PLP) is a common condition that occurs following both upper and lower limb amputation. First recognized and described in 1551 by Ambroise Pare, research into its underlying pathology and effective treatments remains a very active and growing field. To date, however, there is little consensus regarding the optimal management of phantom limb pain. With few large well-designed clinical trials of which to make treatment recommendations, as well as significant heterogeneity in clinical response to available treatments, the management of PLP remains challenging. Below we summarize the current state of knowledge in the field, as well as propose an algorithm for the approach to the treatment of PLP.

The mechanism of action of pulsed radiofrequency in reducing pain: a narrative review

Pain from nervous or musculoskeletal disorders is one of the most common complaints in clinical practice. Corticosteroids have a high pain-reducing effect, and their injection is generally used to control various types of pain. However, they have various adverse effects including flushing, hyperglycemia, allergic reactions, menstrual changes, immunosuppression, and adrenal suppression. Pulsed radiofrequency (PRF) is known to have a pain-reducing effect similar to that of corticosteroid injection, with nearly no major side effects. Therefore, it has been widely used to treat various types of pain, such as neuropathic, joint, discogenic, and muscle pain. In the current review, we outlined the pain-reducing mechanisms of PRF by reviewing previous studies. When PRF was first introduced, it was supposed to reduce pain by long-term depression of pain signaling from the peripheral nerve to the central nervous system. In addition, deactivation of microglia at the level of the spinal dorsal horn, reduction of proinflammatory cytokines, increased endogenous opioid precursor messenger ribonucleic acid, enhancement of noradrenergic and serotonergic descending pain inhibitory pathways, suppression of excitation of C-afferent fibers, and microscopic damage of nociceptive C- and A-delta fibers have been found to contribute to pain reduction after PRF application. However, the pain-reducing mechanism of PRF has not been clearly and definitely elucidated. Further studies are warranted to clarify the pain-reducing mechanism of PRF.

Spontaneous pain as a challenge of research and management in chronic pain

Spontaneous pain occurring without apparent external stimuli, is a significant complaint of individuals with chronic pain whose mechanisms, somewhat surprisingly, remain poorly understood. Over the past decades, neuroimaging studies start to reveal brain activities accompanying spontaneous pain. Meanwhile, a variety of animal models and behavioral tests have been established, including non-reflexive tests and free-choice tests, which have been shown to be effective in assessing spontaneous pain. For the spontaneous pain mechanisms, multiple lines of research mainly focus on three aspects: (1) sensitization of peripheral nociceptor receptors and ion channels, (2) spontaneous neuronal firing and abnormal activity patterns at the dorsal root ganglion and spinal cord level, (3) functional and structural alterations in the brain, particularly the limbic system and the medial pain pathway. Despite accumulating evidence revealing distinct neuronal mechanisms from evoked pain, we are still far from full understanding of spontaneous pain, leaving a big gap between bench and bedside for chronic pain treatment. A better understanding of the neural processes in chronic pain, with specific linkage as to which anatomical structures and molecules related to spontaneous pain perception and comorbidities, will greatly improve our ability to develop novel therapeutics.

Pain Treatment in the Companion Canine Model to Validate Rodent Results and Incentivize the Transition to Human Clinical Trials

One of the biggest challenges for analgesic drug development is how to decide if a potential analgesic candidate will work in humans. What preclinical data are the most convincing, incentivizing and most predictive of success? Such a predicament is not unique to analgesics, and the pain field has certain advantages over drug development efforts in areas like neuropsychiatry where the etiological origins are either unknown or difficult to ascertain. For pain, the origin of the problem frequently is known, and the causative peripheral tissue insult might be observable. The main conundrum centers around evaluation of translational cell- and rodent-based results. While cell and rodent models are undeniably important first steps for screening, probing mechanism of action, and understanding factors of adsorption, distribution metabolism and excretion, two questions arise from such studies. First, are they reliable indicators of analgesic performance of a candidate drug in human acute and chronic pain? Second, what additional model systems might be capable of increasing translational confidence? We address this second question by assessing, primarily, the companion canine model, which can provide particularly strong predictive information for candidate analgesic agents in humans. This statement is mainly derived from our studies with resiniferatoxin (RTX) a potent TRPV1 agonist but also from protein therapeutics using a conjugate of Substance P and saporin. Our experience, to date, is that rodent models might be very well suited for acute pain translation, but companion canine models, and other large animal studies, can augment initial discovery research using rodent models for neuropathic or chronic pain. The larger animal models also provide strong translational predictive capacity for analgesic performance in humans, better predict dosing parameters for human trials and provide insight into behavior changes (bladder, bowel, mood, etc.) that are not readily assessed in laboratory animals. They are, however, not without problems that can be encountered with any experimental drug treatment or clinical trial. It also is important to recognize that pain treatment is a major veterinary concern and is an intrinsically worthwhile endeavor for animals as well as humans.

A scoping review of current non-pharmacological treatment modalities for phantom limb pain in limb amputees

PURPOSE

Phantom limb pain (PLP) is a chronic neuropathic pain condition of a missing limb following amputation. Pain management is multi-modal, including various non-pharmacological therapies. The purpose of this scoping review was to investigate the evidence surrounding current non-pharmacological treatment modalities for PLP and provide insight into their clinical feasibility.

METHOD

A systematic search was conducted using four databases (Medline, Embase, PsychInfo, and CINAHL) following the PRISMA-ScR method. Results from papers meeting the inclusion criteria were charted to summarize findings, demographics, and use of neuroimaging.

RESULTS

A total of 3387 papers were identified, and full texts of 142 eligible papers were assessed. Eleven treatment modalities for PLP were identified with varying levels of evidence. Overall, there were 25 RCTs, 58 case reports, and 59 a combination of pilot, quasi-experimental, observational, and other study designs.

CONCLUSIONS

Currently, the evidence surrounding most treatment modalities is limited and only a fraction of studies are supported by strong evidence. The findings of this review demonstrated a clear need to conduct more rigorous research with diverse study designs to better understand which modalities provide the most benefit and to incorporate neuroimaging to better determine the neural correlates of PLP and mechanisms of various treatments.Implications for RehabilitationPhantom limb pain (PLP) is a prevalent and debilitating condition following amputation and health care professionals should incorporate an evidence-based pain management protocol into their rehabilitation program.There exist a number of different non-pharmacological therapies to address PLP, however the scientific rigor and levels of evidence vary across modalities.Prescription of interventions for PLP should consider individual patient differences, accessibility to the patient, and quite possibly, a multi-modal approach, particularly for those who also experience residual limb pain.Imagery-based therapies provide the highest level of current evidence based on robust and large randomized control trials, are readily accessible, and are thus most recommended for relief of PLP.

Residual limb pain: An evidence-based review

Acquired limb loss, whether from accident or amputation, occurs with an incidence of greater than 175,000 per year in the United States. Current prevalence is estimated at greater than 1.5 million and is expected to double within 30 years. While many patients with amputations may have no significant pain or sensory issues after healing from the initial loss, one-quarter to one-half of patients may have ongoing difficulties with residual limb pain, phantom limb pain, or phantom limb sensation. This review explores the potential etiologies of those symptoms, as well as a variety of treatment options that a practitioner may consider when approaching this condition.

Use of Pulsed Radiofrequency for the Treatment of Discogenic Back Pain: A Narrative Review

BACKGROUND

Low-back pain (LBP) is one of the most frequently reported symptoms of patients who visit pain clinics, and a significant proportion of them have discogenic pain. Pulsed radiofrequency (PRF) stimulation is an effective treatment for various types of pain.

PURPOSE

We reviewed articles which investigated the effectiveness of intradiscal PRF for controlling discogenic LBP.

METHODS AND MATERIALS

We searched PubMed for papers published prior to August 7, 2020, in which intradiscal PRF was used for treating discogenic LBP. The key search phrase was (intradiscal PRF) for identifying potentially relevant articles. We included articles in which intradiscal PRF was used for controlling LBP. Review articles were excluded.

RESULTS

Nine publications were included in this review. Except for one study, all other studies showed positive therapeutic outcomes after treating discogenic LBP using intradiscal PRF. However, the quality of these studies was not high.

CONCLUSIONS

This review showed that intradiscal PRF appears to be a helpful treatment method for patients with discogenic LBP. Our review provides insights into the degree of evidence of the therapeutic effects of intradiscal PRF for alleviating discogenic LBP. For confirmation of the effectiveness of intradiscal PRF on discogenic LBP, more high-quality studies are necessary.

Ultrasonography-Guided Radiofrequency Ablation for Painful Stump Neuromas to Relieve Postamputation Pain: A Pilot Study

Objective

Postamputation pain (PAP) is a serious problem, and thus far, there is no perfect treatment strategy. Clinically, minimally invasive treatments for peripheral neuromas are simple and feasible. This study aimed to investigate the immediate and long-term effects of ultrasonography-guided radiofrequency ablation (RFA) on PAP.

Methods

Eighteen PAP subjects with painful peripheral neuromas were treated with ultrasonography-guided RFA.

Results

A total of 18 PAP subjects were included in the final analyses. Fourteen of the 17 subjects with residual limb pain (RLP) (82.4%) had successful outcomes. A successful outcome was noted in 9 of the 13 subjects with phantom limb pain (PLP) (69.2%). There were no significant associations between symptom relief and sex, age, or the duration of symptoms. There were no severe complications.

Conclusions

Ultrasonography-guided RFA for painful stump neuromas can effectively relieve stump pain and PLP in amputees with PAP (follow-up time was 12 months). Ultrasonography-guided RFA is easy and safe and does not involve radiation exposure, making it very suitable for clinical applications.

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.

The Outcome of Pulsed Radiofrequency Treatment According to Electodiagnosis in Patients with Intractable Lumbosacral Radicular Pain

BACKGROUND

Radicular pain is related to lesions that either directly compromise the dorsal root ganglion (DRG) or indirectly compromise the spinal nerve and its roots by causing ischemia or inflammation of the axons.

OBJECTIVE

Our study aimed to assess the outcomes of pulsed readiofrequency treatment (PRF) according to electrodiagnosis results in patients with chronic intractable lumbosacral radicular pain.

METHODS

A total of 82 failed back surgery syndrome (FBSS) patients were included in this study. All of them underwent electromyography/nerve conduction studies before pulsed radiofrequency (PRF) treatment at the DRG, and they were classified according to the electrodiagnostic results as: group 1, no definite finding (normal); group 2, radiculopathy; and group 3, neuropathy. Pain intensity was assessed according to a numeric rating scale score and the Oswestry Disability Index (ODI) before treatment and at one, three, six, and 12 months after treatment, and successful treatment was defined as a pain score reduction of ≥50% at 12 months, as compared with the pretreatment score.

RESULTS

Pretreatment electrodiagnosis identified 28 patients with no definite findings, 31 patients with radiculopathy, and 23 patients with neuropathy. The patients with neuropathy had less pain relief after treatment than those with no definite findings and those with radiculopathy. The prevalence of pain reduction of at least 50% was lower in the neuropathy group than in the other groups. There was no statistically significant difference in ODI between group.

CONCLUSION

Outcomes after PRF at the DRG did not show strong differences according to electrodiagnostic findings in FBSS patients with chronic intractable lumbosacral radicular pain.

The Effectiveness of Pulsed Radiofrequency on Joint Pain: A Narrative Review

BACKGROUND

Pulsed radiofrequency (PRF) stimulation has been safely and effectively applied for controlling various types of pain.

PURPOSE

We reviewed the literature on the efficacy of PRF for controlling pain in joint disorders.

METHODS

We searched PubMed for papers published prior to September 7, 2019, that used PRF to treat pain due to joint disorders. The key search phrases for identifying potentially relevant articles were (PRF AND joint) OR (PRF AND arthritis) OR (PRF AND arthropathy). The following inclusion criteria were applied for the selection of articles: (1) patients' pain was caused by joint disorders; (2) PRF stimulation was applied to manage joint-origin pain; and (3) after PRF stimulation, follow-up evaluation was performed to assess the reduction in pain intensity. Moreover, joints with more than 3 reported PRF studies were included in our review.

RESULTS

The primary literature search yielded 141 relevant papers. After reading their titles and abstracts and assessing their eligibility based on the full-text articles, we finally included 34 publications in this review. Based on the positive therapeutic outcomes of previous studies, PRF stimulation seems to be an effective treatment for cervical and lumbar facet, sacroiliac, knee, and glenohumeral joint pain. PRF appears to be beneficial. For confirmation of the effectiveness of PRF on joint pain, more high-quality studies are needed.

CONCLUSIONS

Our review provides insights on the degree of evidence according to pain in each joint, which will help clinicians make informed decisions for using PRF stimulation in various joint pain conditions.

Effectiveness of pulsed radiofrequency treatment on cervical radicular pain: A meta-analysis

BACKGROUND

Cervical radicular pain is a challenging medical problem in terms of therapeutic management. Recently, pulsed radiofrequency (PRF) stimulation on the dorsal root ganglion (DRG) has been used to control several types of chronic pain. However, its effect on cervical radicular pain is still not well studied. To conduct a meta-analysis of available clinical studies on PRF treatment in patients with cervical radicular pain induced by cervical spine disease that was not responsive to other conservative treatments.

METHODS

A comprehensive database search was conducted on PubMed, Embase, Cochrane Library, and SCOPUS. We included studies published up to August 31, 2017, that fulfilled our inclusion and exclusion criteria. The pain degrees measured using visual analog scale (VAS) at pretreatment and after PRF on the DRG were collected for the meta-analysis. The Cochrane Collaboration's Handbook and Newcastle-Ottawa scale were used for the methodological quality assessments of included studies. The meta-analysis was performed using the Comprehensive Meta-analysis Version 2.

RESULTS

A total of 67 patients from one RCT study, 2 prospective observational studies, and one retrospective study were included in this meta-analysis. The pooled data of the 4 included studies showed that overall VAS after the PRF treatment was significantly reduced (P ≤ .001). In the subgroup analysis according to follow-up evaluation time points, the pain was significantly reduced at 2 weeks, 1 month, 3 months, and 6 months after the procedure (2 weeks: P = .02; 1, 3, and 6 months: P < .001).

CONCLUSION

According to the results of the meta-analysis, the use of PRF on the DRG is effective for alleviating cervical radicular pain, which was unresponsive to oral medications, physical therapy, or epidural steroid injection.

Effect of intradiscal pulsed radiofrequency on refractory chronic discogenic neck pain: A case report

RATIONALE

Despite medication, exercise, and medical intervention, many patients complain of persistent discogenic neck pain. To manage discogenic neck pain, we performed intradiscal pulsed radiofrequency (PRF) stimulation in a patient with chronic discogenic neck pain refractory to oral medication and epidural steroid injection.

PATIENT CONCERNS

A 26-year-old man presented with a numeric rating scale (NRS) score of 7 for chronic neck pain. His pain was worse when the neck was held in one position for a prolonged period. There was no pain in the upper extremities.

DIAGNOSES

Discography was positive at C4-5. Based on the pain characteristics, and the result of discography, we diagnosed him as having discogenic neck pain originating from C4-5.

INTERVENTIONS

Intradiscal PRF on the C4-5 intervertebral disc was performed under C-arm fluoroscopy. The PRF treatment was administered at 2 Hz and a 20-ms pulsed width for 20 minutes at 60 V with the constraint that the electrode tip temperature should not exceed 42°C.

OUTCOMES

At the 2-week, and 1-month follow-up visits, the patient's pain was completely relieved. At 2, and 3 months after intradiscal PRF, the pain was scored as NRS 2. No adverse effects of intradiscal PRF stimulation were observed.

LESSONS

Application of intradiscal PRF appears to be an effective and safe technique for treating chronic discogenic neck pain.

Effect of Pulsed Radiofrequency Treatment on the Thoracic Medial Branch for Managing Chronic Thoracic Facet Joint Pain Refractory to Medial Branch Block with Local Anesthetics

OBJECTIVE

To evaluate the effect of pulsed radiofrequency (PRF) stimulation of the thoracic medial branch of the dorsal ramus in patients with chronic thoracic facet joint (TFJ) pain who were refractory to medial branch block (MBB).

METHODS

This was a prospective, observational study. The author retrospectively reviewed data from 72 patients who had received therapeutic MBB with 0.5 mL of 2% lidocaine mixed with 0.5 mL of 0.25% bupivacaine to treat TFJ-origin upper or midback pain. Of these patients, 20 were included to evaluate the effects of PRF on the thoracic medical branch to manage TFJ pain refractory to therapeutic MBB. PRF stimulation was administered at 5 Hz and a 5-millisecond pulsed width for 360 seconds at 45 V. The pain-reducing effect of the PRF procedure was evaluated via the numeric rating scale (NRS) at 1, 2, and 3 months after treatment. Successful pain relief was defined as ≥50% reduction in the NRS score compared with the score before treatment.

RESULTS

The NRS scores changed significantly over time (pretreatment, 6.0 ± 1.0; 1 month, 3.3 ± 2.2; 2 months, 3.9 ± 2.1; and 3 months, 4.0 ± 2.2). At 1, 2, and 3 months after the PRF procedure, the NRS scores were significantly reduced compared with the scores before the treatment. Eleven (55%) of 20 patients reported successful pain relief at 3 months after PRF.

CONCLUSIONS

The author suggests that PRF on the thoracic medial branch is an effective and safe interventional technique for the control of chronic TFJ pain.

Prevention of Painful Neuroma and Phantom Limb Pain After Transfemoral Amputations Through Concomitant Nerve Coaptation and Collagen Nerve Wrapping

BACKGROUND

Postamputation pain is a debilitating condition that affects almost 60% of transfemoral amputees. Recent appreciation for the contribution of peripheral nerve derangement to the development of postamputation pain has resulted in focus on the role of nerve reconstruction in preventing pain after amputation.

OBJECTIVE

To propose a method involving tibial and common peroneal nerve coaptation at the time of amputation, as a means to prevent residual limb pain and phantom sequelae resulting from neuroma formation.

METHODS

Between May 2014 and May 2015, 17 patients underwent transfemoral amputation and nerve management through either (1) common peroneal nerve-to- tibial nerve coaptation and collagen nerve wrapping or (2) traction neurectomy alone. Visual analog scores (VAS) for pain, analgesic requirements, neuroma formation, phantom pain/sensations, and ambulatory status were compared between cohorts.

RESULTS

Six patients underwent nerve coaptation/collagen nerve wrapping, whereas 11 underwent traction neurectomy. At 2 months, VAS scores were similar between cohorts (3 vs 3.82; P = .88); however, neuroma (0% vs 36.3%; P = .24) and phantom pain (0% and 54.5%; P = .03) were significantly lower after coaptation. After 6 months, VAS scores (0.75 vs 5.6; P = .02) as well as neuroma (0% vs 54.5%; P = .03) and phantom pain (0% vs 63.6%; P = .01) remained lower among patients who underwent coaptation. At follow-up, 67% of coaptation patients were ambulating with a prosthesis vs 9% of neurectomy patients (P = .01).

CONCLUSION

Preemptive coaptation and collagen nerve wrapping is associated with lower VAS pain scores, phantom symptoms, and neuroma formation, with higher ambulation rates after 6 months when compared with traction neurectomy alone.

ABBREVIATIONS

CPN, common peroneal nervePAP, Postamputation painPLP, phantom limb painPS, phantom sensationsRLP, residual limb painTN, tibial nerve.

Management of refractory sciatic neuropathic pain using ultrasound-guided pulsed radiofrequency

BACKGROUND AND OBJECTIVE

Nowadays, pulsed radiofrequency (PRF) is being used to control several types of musculoskeletal pain. Herein, we report a successful application of ultrasound (US)-guided PRF for a patient with refractory sciatic neuropathic pain.

CASE REPORT

We applied US-guided PRF to a 50-year-old man, suffering from refractory neuropathic pain on the left foot following sciatic neuropathy for a period of approximately 6 months. We performed PRF on the level of piriformis muscle because the lesion of the sciatic nerve was presented digitally from the level of piriformis muscle on the magnetic resonance images. Under US guidance, the catheter needle was placed close to the left sciatic nerve, and dysesthesia and tingling sensation were reported to be less than 0.2 V. The PRF treatment was administered at 5 Hz and 5 ms pulsed width for 360 seconds at 45 V. After PRF on the left sciatic nerve, pain intensity - based on a numeric rating scale - decreased from 8 to 2. The reduction of pain was sustained for at least 6 months after the PRF procedure.

CONCLUSION

We concluded that the PRF treatment is a very useful treatment technique for patients with refractory sciatic neuropathy.

Comparison between bipolar pulsed radiofrequency and monopolar pulsed radiofrequency in chronic lumbosacral radicular pain: A randomized controlled trial

BACKGROUND

Chronic lumbosacral radicular pain is a challenging medical problem with respect to therapeutic management. Many patients with lumbosacral radicular pain complain of persistent leg pain after transforaminal epidural steroid injection. Nowadays, pulsed radiofrequency (PRF) stimulation on the dorsal root ganglion (DRG) is widely used for controlling lumbosacral radicular pain.

METHODS

We evaluated the effect of bipolar PRF on the DRG for the management of lumbosacral radicular pain. In addition, we compared the effect of bipolar PRF to monopolar PRF. Fifty patients with chronic lumbosacral radicular pain were included in the study and randomly assigned to 1 of 2 groups, the bipolar or monopolar PRF group (n = 25 per group). Pain intensity was evaluated using a numeric rating scale (NRS) at pretreatment, and 1, 2, and 3 months after treatment.

RESULTS

When compared to the pretreatment NRS scores, patients in both groups showed a significant decrease in NRS scores at 1, 2, and 3 months after treatment. Reductions in the NRS scores over time were significantly larger in the bipolar PRF group. Three months after treatment, 19 patients (76.0%) in the bipolar PRF group and 12 patients (48.0%) in the monopolar PRF group reported successful pain relief (pain relief of ≥50%).

CONCLUSION

The use of bipolar PRF on the DRG can be an effective and safe interventional technique for chronic refractory lumbosacral radiculopathy, particularly in patients whose pain are refractory to epidural steroid injection or monopolar PRF stimulation.

Ultrasound-guided alcohol neurolysis and radiofrequency ablation of painful stump neuroma: effective treatments for post-amputation pain

BACKGROUND

Post-amputation pain (PAP) is highly prevalent after limb amputation, and stump neuromas play a key role in the generation of the pain. Presently, PAP refractory to medical management is frequently treated with minimally invasive procedures guided by ultrasound, such as alcohol neurolysis and radiofrequency ablation (RFA).

OBJECTIVE

To record the immediate and long-term efficacy of alcohol neurolysis and RFA. We first used alcohol neurolysis and then, when necessary, we performed RFA on PAP patients.

STUDY DESIGN

Prospective case series.

SETTING

Pain management center.

METHODS

Thirteen subjects were treated with ultrasound-guided procedures.

RESULTS

All patients were treated with neurolysis using alcohol solutions guided by ultrasound. Seven (54%) of 13 subjects achieved pain relief after 1-3 alcohol injection treatments. The remaining 6 subjects obtained pain relief after receiving 2 administrations of ultrasound-guided RFA. After a 6-month follow-up evaluation period, pain quantities were also assessed. Both stump pain (including intermittent sharp pain and continuous burning pain) and phantom pain were relieved. The frequency of intermittent sharp pain was decreased, and no complications were noted during the observation.

CONCLUSION

The use of ultrasound guidance for alcohol injection and RFA of painful stump neuromas is a simple, radiation-free, safe, and effective procedure that provides sustained pain relief in PAP patients. In this case series, RFA was found to be an effective alternative to alcohol injection.

Recent Developments in Neuropathic Pain Mechanisms: Implications for Treatment

Neuropathic pain is defined as "pain arising as a direct consequence of a lesion or disease affecting the somatosensory system".Characteristic symptoms include an increased evoked pain response to noxious (hyperalgesia) and innocuous (allodynia) stimuli, spontaneous pain, shooting electric shock like pain. Sensory deficits can also exist.Available treatments are not adequate in many patients due to many factors including the complexity of the pain state, disease progression, intolerable side effects and low analgesic efficacy.A number of peripheral, spinal and supraspinal mechanisms of hyperexcitability underlie neuropathic pain, these include changes in the activity and expression of voltage gated sodium, calcium and potassium channels, as well as TRPV1 channels and alterations in the activity of neuroimmue pathways.NeP patients often experience depression, anxiety, sleep disturbances etc. alongside their pain. These co-morbidites significantly reduce quality of life and as such are key treatment considerations..Improved understanding of NeP mechanisms is encouraging targeting of treatment to the mechanisms that produce painful symptoms as opposed to the etiology of disease.

TNFα secretion of monocytes exposed to pulsed radiofrequency treatment: a possible working mechanism of PRF chronic pain management

Pulsed radiofrequency treatment (PRF) is a promising new technique increasingly used in treatment of chronic pain. The molecular working mechanism of PRF is not exactly known and is currently being investigated. This study investigates a possible role of PRF-induced modulation of TNFα secretion by differentiated monocytes in chronic pain management. The results show no significant PRF-induced change in TNFα secretion of lipopolysaccharides (LPS)-stimulated monocytes. However, PRF does significantly increase TNFα secretion of differentiated monocytes that have not been stimulated with LPS. This may indicate a possible role of PRF treatment in increasing TNFα production of nonstimulated monocytes. More research is needed to determine whether this is truly a part of the working mechanism of PRF in chronic pain management and which other factors are involved.

Postamputation pain: epidemiology, mechanisms, and treatment

Postamputation pain (PAP) is highly prevalent after limb amputation but remains an extremely challenging pain condition to treat. A large part of its intractability stems from the myriad pathophysiological mechanisms. A state-of-art understanding of the pathophysiologic basis underlying postamputation phenomena can be broadly categorized in terms of supraspinal, spinal, and peripheral mechanisms. Supraspinal mechanisms involve somatosensory cortical reorganization of the area representing the deafferentated limb and are predominant in phantom limb pain and phantom sensations. Spinal reorganization in the dorsal horn occurs after deafferentataion from a peripheral nerve injury. Peripherally, axonal nerve damage initiates inflammation, regenerative sprouting, and increased "ectopic" afferent input which is thought by many to be the predominant mechanism involved in residual limb pain or neuroma pain, but may also contribute to phantom phenomena. To optimize treatment outcomes, therapy should be individually tailored and mechanism based. Treatment modalities include injection therapy, pharmacotherapy, complementary and alternative therapy, surgical therapy, and interventions aimed at prevention. Unfortunately, there is a lack of high quality clinical trials to support most of these treatments. Most of the randomized controlled trials in PAP have evaluated medications, with a trend for short-term Efficacy noted for ketamine and opioids. Evidence for peripheral injection therapy with botulinum toxin and pulsed radiofrequency for residual limb pain is limited to very small trials and case series. Mirror therapy is a safe and cost-effective alternative treatment modality for PAP. Neuromodulation using implanted motor cortex stimulation has shown a trend toward effectiveness for refractory phantom limb pain, though the evidence is largely anecdotal. Studies that aim to prevent PA P using epidural and perineural catheters have yielded inconsistent results, though there may be some benefit for epidural prevention when the infusions are started more than 24 hours preoperatively and compared with nonoptimized alternatives. Further investigation into the mechanisms responsible for and the factors associated with the development of PAP is needed to provide an evidence-based foundation to guide current and future treatment approaches.

Painful neuromas

OBJECTIVES

To perform a topical review of the published literature on painful neuromas.

METHODS

A MEDLINE search was performed using the MESH terms "neuroma", "pain", "diagnosis", and "treatment" for all dates.

RESULTS

Acoustic neuromas and intraabdominal neuromas were excluded from a total of 7616 articles. The reference lists from these articles were further reviewed to obtain other relevant articles.

DISCUSSION

Neuromas develop as part of a normal reparative process following peripheral nerve injury. Painful neuromas can induce intense pain resulting in immense suffering and disability. MRI aids the diagnosis, but, ultrasound imaging allows cost effective accurate diagnosis and localization of neuromas by demonstrating their direct contiguity with the nerve of origin. Management options for painful neuromas include pharmacotherapy, prosthetic adjustments, steroid injection, chemical neurolysis, cryoablation, and radiofrequency ablation. Ultrasound imaging guidance has improved the success in localizing and targeting the neuromas. This review discusses the patho-physiology and accumulated evidence for various therapies and the current percutaneous interventional management options for painful neuromas.

A prospective randomized double-blinded pilot study to examine the effect of botulinum toxin type A injection versus Lidocaine/Depomedrol injection on residual and phantom limb pain: initial report

OBJECTIVE

Botulinum toxin type A (Botox) injection has been used to manage pain. However, it remains to be proved whether Botox injection is effective to relieve residual limb pain (RLP) and phantom limb pain (PLP).

DESIGN

Randomized, double-blinded pilot study.

SETTING

Medical College and an outpatient clinic in Department of Physical Medicine and Rehabilitation.

PARTICIPANTS

Amputees (n=14) with intractable RLP and/or PLP who failed in the conventional treatments.

INTERVENTIONS

Study amputees were randomized to receive 1 Botox injection versus the combination of Lidocaine and Depomedrol injection. Each patient was evaluated at baseline and every month after the injection for 6 months.

MAIN OUTCOME MEASURE

The changes of RLP and PLP as recorded by VAS, and the changes of the pressure pain tolerance as determined by a pressure algometer.

RESULTS

All patients completed the protocol treatment without acute side effects, and monthly assessments of RLP, PLP, and pain tolerance after the treatment. The time trend in the outcomes was modeled as an immediate change owing to the treatment followed by a linear tread afterward. Repeated measures were incorporated using mixed effects modeling. We found that both Botox and Lidocaine/Depomedrol injections resulted in immediate improvements of RLP (Botox: P=0.002; Lidocaine/Depomedrol: P=0.06) and pain tolerance (Botox: P=0.01; Lidocaine/Depomedrol: P=0.07). The treatment effect lasted for 6 months in both groups. The patients who received Botox injection had higher starting pain than those who received Lidocaine/Depomedrol injection (P=0.07). However, there were no statistical differences in RLP and pain tolerance between these 2 groups. In addition, no improvement of PLP was observed after Botox or Lidocaine/Depomedrol injection.

CONCLUSIONS

Both Botox and Lidocaine/Depomedrol injections resulted in immediate improvement of RLP (not PLP) and pain tolerance, which lasted for 6 months in amputees who failed in conventional treatments.