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INTRODUCTION: Radiofrequency (RF) treatment of the genicular nerves is a promising treatment for chronic osteoarthritic and persistent postsurgical knee pain (PPSP), refractory to conventional medical management. METHODS: The RECORGEN study is a retrospective single-center cohort study of patients treated with ultrasound-guided conventional RF of the genicular nerves for chronic knee pain in Hospital Oost-Limburg, Genk from September 2017 to June 2020. Subgroup analysis based on etiology of pain (PPSP and degenerative knee pain) was performed in addition to the total study population analysis. Outcome parameters were global perceived effect (GPE), Numeric Rating Scale for pain, consumption of strong opioids, and safety of the treatment at 6 weeks and cross-sectionally at a variable time point. Treatment success was defined as GPE≥50%. RESULTS: Sixty-eight cases were screened of which 59 (46 diagnosed with PPSP and 13 with degenerative knee pain) were included in the study. Treatment success at 6 weeks was achieved in 19 of 59 interventions (32.2%) and was similar in both groups. Seventeen responders were evaluated at follow-up. 45.1% (8/17) continued to have a positive effect at the second time point. The mean duration of effect of the RF treatment was 8.3 months. Safety analysis at 6 weeks and at the second time point showed a good safety profile of the treatment. CONCLUSION: Conventional RF of the genicular nerves was clinically successful in more than 30% of the study population refractory to conventional medical management. Overall, the treatment was well tolerated. The mean duration of effect was 8.3 months. ispartof: PAIN PRACTICE vol:22 issue:3 pages:340-348 ispartof: location:United States status: published

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The recently published "Clinical Relevance of Epidural Steroid Injections on Lumbosacral Radicular Syndrome-Related Complaints: Systematic Review and Meta-Analysis"1 questions whether the current practice of epidural steroid injections (ESIs) for patients suffering from lumbosacral radicular syndrome should continue. Considering the high number of epidural steroid injections that are performed yearly, the methodology may require further assessment. The authors make some statement about the evolution, the cause and the treatment algorithm of lumbosacral radicular pain, that are not completely correct. The papers included in this review are not all of high scientific quality. Papers dealing with patients who suffer lumbosacral radicular pain of 6 weeks to 21 months, which is for beyond the recommended period for the indication of sub-Acute lumbosacral radicular pain. More than one-Third of the studies included in this systematic review reported no medical imaging prior to performing the epidural injection. This heavily compromises the results of the study and the validity of the recommendation. The use of minimal important change (MIC) as an outcome parameter is inappropriate because this outcome measurement was developed to identify clinically meaningful changes within groups or individuals, not to determine significant changes between groups The authors performed 40 meta-Analyses, but most of them were based on 1-3 RCTs. Whereas meta-Analyses containing few studies can yield useful information when the studies evaluate similar patient populations, the procedures are standardized, and the outcome measures are similar, performing meta-Analyses in the presence of significant study heterogeneity, as is present in ESI clinical trials, is a roadmap for showing a biased lack of efficacy.

Introduction Cervical epidural corticosteroid injections are frequently used for the treatment of subacute cervicobrachial pain. This therapy is considered safe, with the vast majority of the complications being minor and transient. Case Report We present a case of a woman in her fifties who suffered from cervicobrachialgia and received 2 cervical epidural corticosteroid infiltrations. On day 3 after the second infiltration, a new headache appeared and on day 16 a bilateral subdural hematoma was visualized on CT scan. Complete resorption of the hematoma was seen on day 25 without surgical intervention. Discussion Up until now, only 1 case report of an intracranial subdural hematoma after a cervical epidural steroid injection has been published. But several cases of an intracranial subdural hematoma after spinal, epidural, or combined spinal and epidural anesthesia have been reported. Physicians should be aware of this potentially dramatic complication since post‐dural puncture headache after any type of procedure can evolve into a subdural hematoma. Clinical differentiation between the two can be difficult; post‐dural puncture headache is characterized by relief of symptoms in the supine position and photophobia/phonophobia. A subdural hematoma should be considered if the headache changes in character, does not respond to treatment, or there are neurological signs such as nausea/vomiting and blurred vision. Immediate medical imaging should then be performed.

STUDY DESIGN: This is a retrospective, observational study.INTRODUCTION: Spinal cord stimulation (SCS) has found its application in chronic pain treatment, with failed back surgery syndrome (FBSS) as one of the most important indications. However, to date, little is known about the long-term effectiveness of the treatment. The aim of this study is to analyze retrospectively the long-term outcomes of SCS treatment in a single multidisciplinary pain center on predominant radicular pain, using devices of a single manufacturer.MATERIALS AND METHODS: Patient data on overall patient satisfaction, pain intensity, and adverse events were retrospectively collected in our clinical practice between January 1998 and January 2018, for 191 patients who received a permanent SCS implant. Secondary health measures included the influence of opioid and nicotine use on pain reduction after therapy.RESULTS: The trial-to-implant ratio was 93.6%. At a mean follow-up of 10.6 years, 78.5% of the patients were satisfied with the treatment outcome, with a significant pain reduction of an average three points on a Numeric Rating Scale. Opioid and nicotine usage did not have a significant link with the pain reduction one year after the treatment. Furthermore, devices had an average battery lifespan of 8.4 years. A total of 248 revisions were recorded. A total of 24 patients (11.7%) acquired an infection; 7 of 204 patients had an infection during the trial period, 2 of 191 patients had an infection in the first postoperative year, and 15 of 191 patients had an infection after the first year. The average time to infection, if not in the first year, was 10.1 years.CONCLUSIONS: A successful long-term outcome regarding pain relief in patients with predominant radicular pain due to FBSS is established with SCS therapy.

BackgroundRadiofrequency (RF) treatment of the genicular nerves has the potential to reduce chronic knee pain due to osteoarthritis or persistent postsurgical pain, however, a direct comparison between the two main modalities used, conventional and cooled, is lacking.MethodsThis double blind, non-inferiority, pilot, randomized controlled trial compared the effects of cooled and conventional RF in chronic knee pain patients suffering from osteoarthritis or persistent postsurgical pain after total knee arthroplasty. Patients were randomized following a 1:1 rate. The primary outcome was the proportion of patients with ≥50% pain reduction at 3 months postintervention. Other outcomes were knee pain, functionality, quality of life, emotional health, and adverse events up to 6 months postintervention. Conventional RF treatment was tested for non-inferiority to cooled in reducing knee pain at 3 months follow-up.ResultsForty-nine of 70 patients were included, of which 47 completed a 3-month follow-up. The primary outcome was achieved in 4 of 23 patients treated with conventional RF (17%) vs in 8 of 24 with cooled (33%) (p=0,21). Results from the non-inferiority comparison were inconclusive in relation to the non-inferiority margin. There was no statistically significant difference between secondary outcomes. There were no serious adverse events.ConclusionsBoth conventional and cooled RF treatment reduced pain in the osteoarthritis and persistent postsurgical pain population. This pilot study did not demonstrate statistically significant differences in the proportion of patients experiencing ≥50% pain reduction between techniques. The non-inferiority analysis was inconclusive. These results warrant further research.Trial registration numberNCT03865849.

BackgroundThe innervation of the sacroiliac joint (SIJ) is complex, with a dual innervation originating from the lumbosacral plexus anteriorly as well as the sacral lateral branches posteriorly. Nociceptors are found in intra-articular structures as well as periarticular structures. In patients with SIJ pain, a fluoroscopy-guided SIJ injection is usually performed posteriorly into the bottom one-third of the joint with local anesthetic and corticosteroids, but this does not always reach all intra-articular structures. The correlation between a cranial contrast spread and clinical success is undetermined in patients with SIJ pain.MethodsIn a tertiary referral pain center, electronic medical records of patients who underwent an SIJ injection were retrospectively analyzed. Only patients with at least three positive provocation maneuvers for SIJ pain were selected. Contrast images of the SIJ were classified as with or without cranial spread on fluoroscopy as a marker of intra-articular injection. Clinical success was defined as ≥50% improvement in the patient’s global perceived effect after 3–4 weeks. The primary outcome was defined as the correlation between cranial contrast spread and clinical success after an SIJ injection.Results128 patients in total were included. In 68 patients (53.1%) fluoroscopy showed cranial contrast spread. Clinical success was higher in patients with cranial spread of contrast (55 of 68, 81%) versus those without (35 of 60, 58%) (p=0.0067). In a multivariable analysis with age, gender, presence of rheumatoid arthritis, side, and number of positive provocation maneuvers, the cranial spread of contrast remained the only independent factor of clinical success (p=0.006; OR 3.2, 95% CI 1.4 to 7.7).ConclusionIn patients with SIJ pain, identified by positive pain provocation maneuvers, cranial contrast spread as a marker of intra-articular injection, with subsequent injection of 3 mL of local anesthetic and methylprednisolone 40 mg, was significantly correlated with clinical success up to 4 weeks. Therefore, attempts should be made to reach this final needle position before injecting local anesthetic and corticosteroids. This result needs to be confirmed in a high-quality prospective trial.

Contains fulltext : 203254.pdf (Publisher’s version ) (Open Access) BACKGROUND: Epidural corticosteroid injections are used frequently worldwide in the treatment of radicular pain. Concerns have arisen involving rare major neurologic injuries after this treatment. Recommendations to prevent these complications have been published, but local implementation is not always feasible due to local circumstances, necessitating local recommendations based on literature review. METHODS: A work group of 4 stakeholder pain societies in Belgium, The Netherlands, and Luxembourg (Benelux) has reviewed the literature involving neurological complications after epidural corticosteroid injections and possible safety measures to prevent these major neurologic injuries. RESULTS: Twenty-six considerations and recommendations were selected by the work group. These involve the use of imaging, injection equipment particulate and nonparticulate corticosteroids, epidural approach, and maximal volume to be injected. CONCLUSION: Raising awareness about possible neurological complications and adoption of safety measures recommended by the work group aim at reducing the risks for these devastating events.

Contains fulltext : 196107.pdf (Publisher’s version ) (Closed access)

Contains fulltext : 209348.pdf (Publisher’s version ) (Open Access) INTRODUCTION: Between 2009 and 2011 a series of 26 articles on evidence-based medicine for interventional pain medicine according to clinical diagnoses were published. The high number of publications since the last literature search justified an update. METHODS: For the update an independent 3rd party, specialized in systematic reviews was asked in 2015 to perform the literature search and summarize relevant evidence using Cochrane and GRADE methodology to compile guidelines on interventional pain management. The guideline committee reviewed the information and made a last update on March 1st 2018. The information from new studies published after the research performed by the 3th party and additional observational studies was used to incorporate other factors such as side effects and complications, invasiveness, costs and ethical factors, which influence the ultimate recommendations. RESULTS: For the different indications a total of 113 interventions were evaluated. Twenty-seven (24%) interventions were new compared to the previous guidelines and the recommendation changed for only 3 (2.6%) of the interventions. DISCUSSION: This article summarizes the evolution of the quality of evidence and the strength of recommendations for the interventional pain treatment options for 28 clinical pain diagnoses.

We thank Koetsier for his comments. Indeed, the dose of dexamethasone may be a point of discussion. The authors ask to review the recommended dose of 10 mg based on the study of El Abd et al.1 where 15 mg is used for cervical transforaminal epidural injections and 20 mg for lumbar epidurals. This study has, however, as objective to study the immediate and acute adverse effects after transforaminal epidural steroid injections. In the paper no information is given on pain reduction and/or disability. This article is protected by copyright. All rights reserved.

Purpose: Management of patients with persisting pain after spine surgery (PPSS) shows significant variability, and there is limited evidence from clinical studies to support treatment choice in daily practice. This study aimed to develop patient-specific recommendations on the management of PPSS. Methods: Using the RAND/UCLA appropriateness method (RUAM), an international panel of 6 neurosurgeons, 6 pain specialists, and 6 orthopaedic surgeons assessed the appropriateness of 4 treatment options (conservative, minimally invasive, neurostimulation, and re-operation) for 210 clinical scenarios. These scenarios were unique combinations of patient characteristics considered relevant to treatment choice. Appropriateness had to be expressed on a 9-point scale (1 = extremely inappropriate, 9 = extremely appropriate). A treatment was considered appropriate if the median score was ≥ 7 in the absence of disagreement (≥ 1/3 of ratings in each of the opposite sections 1–3 and 7–9). Results: Appropriateness outcomes showedclear and specific patterns. In 48% of the scenarios, exclusively one of the 4 treatments was appropriate. Conservative treatment was usually considered appropriate for patients without clear anatomic abnormalities and for those with new pain differing from the original symptoms. Neurostimulation was considered appropriate in the case of (predominant) neuropathic leg pain in the absence of conditions that may require surgical intervention. Re-operation could be considered for patients with recurrent disc, spinal/foraminal stenosis, or spinal instability. Conclusions: Using the RUAM, an international multidisciplinary panel established criteria for appropriate treatment choice in patients with PPSS. These may be helpful to educate physicians and to improve consistency and quality of care. Graphical abstract: These slides can be retrieved under Electronic Supplementary Material. [Figure not available: see fulltext.].

Background. In a previous prospective study on pulsed radiofrequency (PRF) treatment adjacent to the lumbar dorsal root ganglion (DRG) for patients with chronic lumbosacral radicular pain, we reported success in 55.4% of the patients at 6 months. Identification of predictors for success after PRF may improve outcome. We assessed the predictors of PRF in patients with chronic intractable lumbosacral radicular pain. Methods. Patients with monosegmental chronic lumbosacral radicular pain of L5 or S1 first received a selective nerve root block at the corresponding level. Independent of the result of this block a PRF treatment at the same level was performed. At 6 weeks, 3 months, and 6 months after the procedure the outcome was evaluated. Results. A positive diagnostic nerve root block and age a parts per thousand yen 55 were predictive factors for successful outcome at 6 months, while disability was a negative predictor. The use of failed back surgery syndrome, gender, duration of pain, Numerical Rating Scale, level and side of treatment, DN4, and RAND-36 as predictors for success was not supported. Conclusions. Successful outcome after PRF adjacent to the DRG, in patients with intractable chronic lumbosacral radicular pain, is more likely in patients a parts per thousand yen 55 years, with limited disability and after a positive diagnostic nerve root block. A combination of all these factors creates a fair predictive value (AUC: 0.73).

Department of Anesthesiology, Critical Care and Mul-tidisciplinary Pain Center, ZOL, Genk, BelgiumReprint requests to: Koen Van Boxem, MD, PhD, FIPP,Department of Anesthesiology Critical Care and Multi-disciplinary Pain Center, Sint Jozefkliniek, Bornem enWillebroek, Kasteelstraat 23, 2880 Bornem, Belgium.Tel: 132 3 890 16 94; Fax: 132 3 890 59 23; E-mail:dr.Van.Boxem@sjk.be.Conflict of interest: None of the authors have a conflictof interest.Funding sources: The work has been performed incollaboration between all the authors, without anyfinancial support.AbstractBackground and Objectives. There is little evidenceconcerning the medical management of lumbosacralradicular pain. The prognosis for patients sufferingpain for more than 3 months is poor. Pulsed radiofre-quency (PRF) treatment of the dorsal root ganglion(DRG) has been suggested as a minimally invasivetreatment. We studied the effect on pain and qualityof life of PRF treatment of the DRG in patients withchronic, severe lumbosacral radicular pain.Methods. Patients with lumbosacral radicular painwere screened to select a homogeneous popula-tion. PRF treatment of the DRG was performed at L5or S1. Evaluation was carried out at 6 weeks,3 months, and 6 months. Pain reduction and “fullyrecovered” or “much improvement,” in terms of theglobal perceived effect, were the primary outcomes.Quality of life (RAND-36), disability (Oswestry Dis-ability Index), and the neuropathic pain scales leedsassessment of neuropathic symptoms and signs(LANSS) and DN4 were registered at each timepoint. Medication use was scored with the Medica-tion Quantification Scale.Results. Out of 461 screened patients, 65 wereincluded. According to the intention to treat analy-sis, clinical success was achieved in 56.9%, 52.3%,and 55.4% of the patients at respectively 6 weeks,3 months, and 6 months. DN4, Oswestry DisabilityIndex and physical component for the RAND-36qualityof life improved significantly while the mentalcomponent remained unchanged. The number ofpatients on opioids was reduced.Conclusions. PRF treatment of the DRG may beconsidered for patients with chronic, severe lumbo-sacral radicular pain refractory to conventionalmedical management.Key Words. Radiofrequency; Lumbosacral radicu-lar pain; Pulsed radiofrequency; Dorsal root gan-glion; Conventional Medical ManagementIntroductionLumbosacral radicular (LRS) pain is an important healthcare problem. In the general, population older than 30years of age, up to 5% suffer low back pain radiating1

The increasing number of publications on pulsed radiofrequency (PRF) treatment of chronic pain reflects the interest for this technique. We summarize the literature for PRF in five indications: radicular pain, trigeminal neuralgia (TN), occipital neuralgia, shoulder and knee pain.The efficacy and safety of PRF adjacent to the dorsal root ganglion was documented on cervical and on lumbar level.PRF has been used for the treatment of TN. The observed duration of effect is shorter than that of conventional radiofrequency, but no neurological complications are reported with PRF.PRF of the nervi occipitales is superior to steroid injections in occipital neuralgia.Several studies showed that PRF of the nervus suprascapularis may relief shoulder pain and can improve mobility of the shoulder joint.For the treatment of knee pain, different nerves have been targeted for PRF treatment.PRF treatment has progressively gained a place in the management of chronic pain syndromes. The concept is appealing because long-lasting effects are reported without complications. Future research is needed with high quality randomized controlled trials and identification of the optimal parameters of PRF in clinical practice.

Radicular pain is an important health care problem, with only limited evidence-based treatments available. Treatment selection should ideally target documented pathophysiological pathways. In herniated discs, a sequence in the inflammatory cascade can be observed that initiates and maintains increased nociceptive signal input. Inflammatory mediators including tumor necrosis factor α are released from the nucleus pulposus and the degenerating peripheral nerve, which, in turn, induces production of neurotrophins like nerve growth factor and brain-derived neurotrophic factor. Neurotrophins interfere not only with the generation of ectopic firing of nociceptive neurons in the dorsal root ganglion but also with the excitability and sensitization of neuronal transmission in the dorsal spinal horn. Radicular pain is further characterized by the electrophysiological spreading of the afferent nociceptive input over different spinal nerve roots. Both the complex pathophysiological pathways involved and the spreading of the nociceptive signal make radicular pain difficult to treat. Pulsed radiofrequency (PRF) is considered an option in treatment of radicular pain. To understand and increase the efficiency of PRF interventional treatments in radicular pain, both in vitro and in vivo studies aiming at elucidating part of the mechanism of action of PRF are described. Potential factors that may improve the efficacy of PRF treatment in radicular pain are discussed.

SUMMARY Low back pain is one of the most prominent healthcare problems but there is no gold standard for its diagnosis. Aspecific low back pain can be subdivided into radicular and mechanical pain. The diagnosis mainly relies on a combination of elements, such as medical history, physical examination, medical imaging and other possible additional tests. Once a working diagnosis has been established, confirmation of the causative structure and level is sought by means of diagnostic blocks. The use of the different diagnostic tests and blocks should be guided by the balance between the potential benefit (mainly in terms of improved treatment outcome, the possible burden for the patient and the chances of withholding potential effective treatment to patients) with false-negative test results.

Lumbosacral radicular pain is characterized by a radiating pain in one or more lumbar or sacral dermatomes; it may or may not be accompanied by other radicular irritation symptoms and/or symptoms of decreased function. The annual prevalence in the general population, described as low back pain with leg pain traveling below the knee, varied from 9.9% to 25%, which means that it is presumably the most commonly occurring form of neuropathic pain. The patient's history may give a suggestion of lumbosacral radicular pain. The best known clinical investigation is the straight-leg raising test. Final diagnosis is made based on a combination of clinical examination and potentially additional tests. Medical imaging studies are indicated to exclude possible serious pathologies and to confirm the affected level in patients suffering lumbosacral radicular pain for longer than 3 months. Magnetic resonance imaging is preferred. Selective diagnostic blocks help confirming the affected level. There is controversy concerning the effectiveness of conservative management (physical therapy, exercise) and pharmacological treatment. When conservative treatment fails, in subacute lumbosacral radicular pain under the level L3 as the result of a contained herniation, transforaminal corticosteroid administration is recommended (2 B+). In chronic lumbosacral radicular pain, (pulsed) radiofrequency treatment adjacent to the spinal ganglion (DRG) can be considered (2 C+). For refractory lumbosacral radicular pain, adhesiolysis and epiduroscopy can be considered (2 B+/-), preferentially study-related. In patients with a therapy-resistant radicular pain in the context of a Failed Back Surgery Syndrome, spinal cord stimulation is recommended (2 A+). This treatment should be performed in specialized centers.

Dear Editor, Drs. Freo and Calldero rightfully issued a remark on our odds analysis of the factors predictive for the positive outcome of a pulsed radio frequency (PRF) treatment adjacent to the lumbar dorsal root ganglion. We have to admit that the negative value of the odds ratio is a typographic error. We checked the output of the analysis and the odds ratios should be +0.97 and +0.96. The statistical threshold of 0.1 is quite common; values of 0.15 and 0.2 are also used, …

Background and ObjectivesThe usefulness of adding bupivacaine to an opioid administered by the epidural route is controversial. This study examines both the quality of pain relief and side effects, in particular urinary retention, during patient-controlled epidural analgesia (PCEA) with sufentanil alone or in combination with two different concentrations of bupivacaine.MethodsIn a double-blind randomized study, 60 healthy young adults undergoing open knee or ankle surgery with combined spinal-epidural anesthesia received postoperative analgesia via PCEA with sufentanil alone or with 0.06% or 0.12% bupivacaine. In addition to pain scores at rest and during mobilization, bladder function was evaluated. Strict criteria were respected in scoring the occurrence of problems suggestive of urinary retention. The 24-hour analgesic consumption and the incidence of other side effects were also recorded.ResultsPatients receiving bupivacaine had better pain relief than those receiving only the opioid, but this difference was more pronounced when measuring dynamic pain scores. The consumption of sufentanil was significantly higher in the group receiving the opioid alone than in the group receiving 0.06% bupivacaine. The bupivacaine dose requirements were twice as high with the 0.12% concentration. Bladder problems occurred significantly more frequently in patients treated with the highest bupivacaine concentration. Motor impairment was not a major problem.ConclusionsA 0.06% bupivacaine-sufentanil combination offered the best results in terms of analgesic quality and lower side effects, mainly micturition problems, which may be explained by the higher consumption of local anesthetic at the higher bupivacaine concentration. Analgesic quality could not be improved by increasing the bupivacaine concentration.

Radicular pain is an important health care problem, with only limited evidence-based treatments available. Treatment selection should ideally target documented pathophysiological pathways. In herniated discs, a sequence in the inflammatory cascade can be observed that initiates and maintains increased nociceptive signal input. Inflammatory mediators including tumor necrosis factor α are released from the nucleus pulposus and the degenerating peripheral nerve, which, in turn, induces production of neurotrophins like nerve growth factor and brain-derived neurotrophic factor. Neurotrophins interfere not only with the generation of ectopic firing of nociceptive neurons in the dorsal root ganglion but also with the excitability and sensitization of neuronal transmission in the dorsal spinal horn. Radicular pain is further characterized by the electrophysiological spreading of the afferent nociceptive input over different spinal nerve roots. Both the complex pathophysiological pathways involved and the spreading of the nociceptive signal make radicular pain difficult to treat. Pulsed radiofrequency (PRF) is considered an option in treatment of radicular pain. To understand and increase the efficiency of PRF interventional treatments in radicular pain, both in vitro and in vivo studies aiming at elucidating part of the mechanism of action of PRF are described. Potential factors that may improve the efficacy of PRF treatment in radicular pain are discussed.

Pascal Vanelderen, MD, FIPP*; Koen Van Boxem, MD, FIPP; Jan Van Zundert, MD, PhD, FIPP* *Department of Anesthesiology, Intensive Care Medicine and Multidisciplinary Pain Clinic, Ziekenhuis Oost-Limburg, Genk, Belgium; Department of Anesthesiology, Pain and Palliative Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Department of Anesthesiology and Pain Management, Sint-Jozefkliniek Bornem-Willebroek, Belgium; Maastricht University Medical Centre, Maastricht, The Netherlands

“Injection therapy and denervation procedures for chronic low back pain: a systematic review” [1] evaluates the effect of two broadly defined treatment options for chronic low back pain. This forms indeed a burden to patients, society and physicians. Lack of knowledge of the causes of chronic pain and poor understanding of patient heterogeneity in pathophysiologic mechanisms and treatment response are a major explanation for unsuccessful trials [2]. Clinical research reaches the conclusion that a “mechanism-based” treatment approach in which therapeutic interventions target the specific mechanisms of a patient’s pain is recommended [2]. Low back pain is divided into specific form due to fracture tumor, infection, etc and the aspecific form. We generally differentiate between degenerative diseases of the facet joints or of the intervertebral disc and radicular pain. The described inclusion and exclusion criteria for the studies to be withheld in this systematic review [1]; however, suggest that the research group lacks the input of a clinical experts who can provide information regarding the clinical diagnoses and the potential underlying mechanisms. In contrast, instead of following recent recommendations, pain syndromes with different underlying mechanisms are clearly mixed in the expectation to draw clinically relevant information on a therapeutic intervention. Moreover, also treatments with no indication in a clinical setting are analyzed, which troubles even more the evidence. Under the heading injection therapy, injections of medication and proteolytic agents are considered and it is for the clinician strange to have epidural and facet joint injections discussed in the same line as local injections in spinal muscles. Moreover, the epidural injections are recommended for the management of subacute low back pain radiating into the leg. This means pain of a duration between 6 weeks and 3 months. Obviously because of the predefined criteria for inclusion of studies on patients with pain of duration of more than 3 months, the authors eliminate the most important trials on this treatment option. Of the three studies that are maintained for further analysis only the trial on targetted steroid placement deals with patients suffering radicular pain. Evidence-based practice guidelines [3] clearly indicate that the only indication for epidural corticosteroid administration is the management of subacute radicular pain. Epidural administration of local anesthetic may be used in surgery and postoperative pain control, but is not recommended for the management of chronic pain, mainly because of the short duration of action of the local anesthetic and the lack of mechanism/cause oriented mode of action. The authors suggest a lack of clinical understanding and differentiation between degenerative disease of the facet joints and lumbosacral radicular pain because under the heading “zygapophysial joints (facet joints)” they also list the RCT comparing radiofrequency treatment adjacent to the dorsal root ganglion with sham intervention. This study was performed in patients suffering chronic lumbosacral radicular pain. In a recent letter to the editor [4], a plea was made to include clinicians in the definition of the research question before starting a systematic review to obtain more clinically relevant information.

Lumbosacral radicular pain is characterized by a radiating pain in one or more lumbar or sacral dermatomes; it may or may not be accompanied by other radicular irritation symptoms and/or symptoms of decreased function. The annual prevalence in the general population, described as low back pain with leg pain traveling below the knee, varied from 9.9% to 25%, which means that it is presumably the most commonly occurring form of neuropathic pain. The patient's history may give a suggestion of lumbosacral radicular pain. The best known clinical investigation is the straight-leg raising test. Final diagnosis is made based on a combination of clinical examination and potentially additional tests. Medical imaging studies are indicated to exclude possible serious pathologies and to confirm the affected level in patients suffering lumbosacral radicular pain for longer than 3 months. Magnetic resonance imaging is preferred. Selective diagnostic blocks help confirming the affected level. There is controversy concerning the effectiveness of conservative management (physical therapy, exercise) and pharmacological treatment. When conservative treatment fails, in subacute lumbosacral radicular pain under the level L3 as the result of a contained herniation, transforaminal corticosteroid administration is recommended (2 B+). In chronic lumbosacral radicular pain, (pulsed) radiofrequency treatment adjacent to the spinal ganglion (DRG) can be considered (2 C+). For refractory lumbosacral radicular pain, adhesiolysis and epiduroscopy can be considered (2 B+/-), preferentially study-related. In patients with a therapy-resistant radicular pain in the context of a Failed Back Surgery Syndrome, spinal cord stimulation is recommended (2 A+). This treatment should be performed in specialized centers.

There are currently 6 reviews on (pulsed) radiofrequency (RF) for the management of spinal pain. Two reviews on interventional pain management techniques in general also discuss RF. The outcomes of those reviews depend on the type of studies included and the opinion of the reviewers, which may result in different evidence levels. Radiofrequency denervation at the cervical and lumbar level has produced the most solid evidence. The differences in treatment outcome registered in the 5 randomized controlled trials (RCTs) regarding lumbar facet denervation can be attributed to differences in patient selection and/or inappropriate technique. There is not sufficient evidence supporting the use of RF facet denervation for the management of cervicogenic headache. The studies examining the management of cervical radicular pain suggest a comparable efficacy for RF and pulsed RF (PRF). The PRF treatment is supposed to be safer and therefore should be preferred. The superiority of RF treatment adjacent to the lumbar dorsal root ganglion for the management of lumbar radicular pain has not been demonstrated in an RCT. Information regarding RF treatment of sacroiliac joint pain is accumulating. No randomized sham-controlled trials on the value of RF treatment of the Gasserian ganglion for the management of idiopathic trigeminal neuralgia have been published. One RCT indicates superiority of RF over PRF for the management of idiopathic trigeminal neuralgia. Future research to confirm or deny the efficacy of (P)RF should be conducted in carefully selected patient populations. The tests used for patient inclusion in such a trial could potentially help the clinician in selecting patients for this type of treatment. The value of PRF treatment of the peripheral nerves also needs to be confirmed in well-designed trials.

Dear Editor, We thank Dr. Bhatia for asking for some clarification on our study design and interpretation of a 6-month cohort study on PRF related to chronic intractable radicular pain [1]. 1. The maintenance and flexibility of conventional medical management are dictated by ethical and practical considerations. Patients presenting in a pain clinic have already received several types of conventional medical management that may consist of tramadol, amitryptilin, gabapentin, or pregabalin. Stopping this treatment to allow only, for example, tramadol as an escape medication is not justifiable from an ethical point of view when performing a study with a follow-up period of 6 months or longer. There is currently no evidence on the efficacy of any medication in the treatment of lumbasacral radicular pain [2], which made it even …