Does sensory stimulation threshold affect lumbar facet radiofrequency denervation outcomes? A prospective clinical correlational study

Radiofrequency Denervation of the Spine and the Sacroiliac Joint: A Systematic Review based on the Grades of Recommendations, Assesment, Development, and Evaluation Approach Resulting in a German National Guideline

STUDY DESIGN

Systematic review of the literature and subsequent meta-analysis for the development of a new guideline.

OBJECTIVES

This manuscript summarizes the recommendations from a new clinical guideline published by the German Spine Society. It covers the current evidence on recommendations regarding the indication, test blocks and use of radiofrequency denervation. The guidelines aim is to improve patient care and efficiency of the procedure.

METHODS

A multidisciplinary working group formulated recommendations based on the Grades of Recommendations, Assessment, Development, and Evaluation (GRADE) approach and the Appraisal of Guidelines for Research and Evaluation II (AGREE II) instrument.

RESULTS

20 clinical questions were defined for guideline development, with 87.5% consensus achieved by committee members for one recommendation and 100% consensus for all other topics. Specific questions that were addressed included clinical history, examination and imaging, conservative treatment before injections, diagnostic blocks, the injected medications, the cut-off value in pain-reduction for a diagnostic block as well as the number of blocks, image guidance, the cannula trajectories, the lesion size, stimulation, repeat radiofrequency denervation, sedation, cessation or continuation of anticoagulants, the influence of metal hardware, and ways to mitigate complications.

CONCLUSION

Radiofrequency (RF) denervation of the spine and the SI joint may provide benefit to well-selected individuals. The recommendations of this guideline are based on very low to moderate quality of evidence as well as professional consensus. The guideline working groups recommend that research efforts in relation to all aspects of management of facet joint pain and SI joint pain should be intensified.

3. Pain originating from the lumbar facet joints

INTRODUCTION

Pain originating from the lumbar facets can be defined as pain that arises from the innervated structures comprising the joint: the subchondral bone, synovium, synovial folds, and joint capsule. Reported prevalence rates range from 4.8% to over 50% among patients with mechanical low back pain, with diagnosis heavily dependent on the criteria employed. In well-designed studies, the prevalence is generally between 10% and 20%, increasing with age.

METHODS

The literature on the diagnosis and treatment of lumbar facet joint pain was retrieved and summarized.

RESULTS

There are no pathognomic signs or symptoms of pain originating from the lumbar facet joints. The most common reported symptom is uni- or bilateral (in more advanced cases) axial low back pain, which often radiates into the upper legs in a non-dermatomal distribution. Most patients report an aching type of pain exacerbated by activity, sometimes with morning stiffness. The diagnostic value of abnormal radiologic findings is poor owing to the low specificity. SPECT can accurately identify joint inflammation and has a predictive value for diagnostic lumbar facet injections. After "red flags" are ruled out, conservatives should be considered. In those unresponsive to conservative therapy with symptoms and physical examination suggesting lumbar facet joint pain, a diagnostic/prognostic medial branch block can be performed which remains the most reliable way to select patients for radiofrequency ablation.

CONCLUSIONS

Well-selected individuals with chronic low back originating from the facet joints may benefit from lumbar medial branch radiofrequency ablation.

Consensus practice guidelines on interventions for cervical spine (facet) joint pain from a multispecialty international working group

BACKGROUND

The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial.

METHODS

In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4-5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement.

RESULTS

Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation.

CONCLUSIONS

Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Consensus practice guidelines on interventions for cervical spine (facet) joint pain from a multispecialty international working group

Background

The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial.

Methods

In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4–5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement.

Results

Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation.

Conclusions

Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

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

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

Sensory Stimulation Threshold: A Viable Tool to Improve the Outcome of Lumbar Facet Radiofrequency Denervation?

Background

Sensory stimulation threshold (SST) has been used as a surrogate marker to target a nerve branch for radiofrequency (RF) denervation; however, the validity of SST as a prognostic marker is still under debate.

Objective

To assess whether lower SST values correlate with better outcomes of radiofrequency denervation for facetogenic low back pain.

Design

Prospective cohort study.

Patients

Sixty-seven patients who underwent radiofrequency denervation for low back pain.

Methods

Correlations, between the average percentage of pain relief from diagnostic medial branch block (MBB) and RF denervation procedure outcome, and between SST and RF denervation procedure outcome, were analyzed using Spearman correlation coefficient (r_s). Wilcoxon rank sum test was performed to assess whether magnitude and duration of pain relief following RF denervation differed by the levels of SST (<0.5 and ≥0.5) or pain relief (<80% and ≥80%) from diagnostic MBB.

Results

There was a positive correlation between pain relief after diagnostic MBB and pain relief 2 weeks after denervation (r_s 0.31, 95% CI 0.08 to 0.51, p < 0.01), but not between pain relief after MBB and pain relief 6 months after denervation, nor pain relief duration after denervation. There was a negative correlation between SST and pain relief 6 months after denervation (r_s −0.41, 95% CI −0.59 to −0.18, p < 0.001). There was also a negative correlation between SST and pain relief duration after denervation (r_s −0.33, 95% CI −0.53 to −0.09, p < 0.01).

Conclusion

SST is a viable measurement with which to guide needle placement during RF denervation for lumbar facet pain, and enhances pain relief outcomes.

Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group

BACKGROUND

The past two decades have witnessed a surge in the use of lumbar facet blocks and radiofrequency ablation (RFA) to treat low back pain (LBP), yet nearly all aspects of the procedures remain controversial.

METHODS

After approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, letters were sent to a dozen pain societies, as well as representatives from the US Departments of Veterans Affairs and Defense. A steering committee was convened to select preliminary questions, which were revised by the full committee. Questions were assigned to 4-5 person modules, who worked with the Subcommittee Lead and Committee Chair on preliminary versions, which were sent to the full committee. We used a modified Delphi method, whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chair, who incorporated the comments and sent out revised versions until consensus was reached.

RESULTS

17 questions were selected for guideline development, with 100% consensus achieved by committee members on all topics. All societies except for one approved every recommendation, with one society dissenting on two questions (number of blocks and cut-off for a positive block before RFA), but approving the document. Specific questions that were addressed included the value of history and physical examination in selecting patients for blocks, the value of imaging in patient selection, whether conservative treatment should be used before injections, whether imaging is necessary for block performance, the diagnostic and prognostic value of medial branch blocks (MBB) and intra-articular (IA) injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for a prognostic block, how many blocks should be performed before RFA, how electrodes should be oriented, the evidence for larger lesions, whether stimulation should be used before RFA, ways to mitigate complications, if different standards should be applied to clinical practice and clinical trials and the evidence for repeating RFA (see table 12 for summary).

CONCLUSIONS

Lumbar medial branch RFA may provide benefit to well-selected individuals, with MBB being more predictive than IA injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of more false-negatives. Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Randomized prospective trial of cooled versus traditional radiofrequency ablation of the medial branch nerves for the treatment of lumbar facet joint pain

BACKGROUND AND OBJECTIVES

No previous study has assessed the outcomes of cooled radiofrequency ablation (C-RFA) of the medial branch nerves (MBN) for the treatment of lumbar facet joint pain nor compared its effectiveness with traditional RFA (T-RFA). This study evaluated 6-month outcomes for pain, function, psychometrics, and medication usage in patients who underwent MBN C-RFA versus T-RFA for lumbar Z-joint pain.

METHODS

In this blinded, prospective trial, patients with positive diagnostic MBN blocks (>75% relief) were randomized to MBN C-RFA or T-RFA. The primary outcome was the proportion of 'responders' (≥50% Numeric Rating Scale (NRS) reduction) at 6 months. Secondary outcomes included NRS, Oswestry Disability Index (ODI), and Patient Global Impression of Change.

RESULTS

Forty-three participants were randomized to MBN C-RFA (n=21) or T-RFA (n=22). There were no significant differences in demographic variables (p>0.05). A ≥50% NRS reduction was observed in 52% (95% CI 31% to 74%) and 44% (95% CI 22% to 69%) of participants in the C-RFA and T-RFA groups, respectively (p=0.75). A ≥15-point or ≥30% reduction in ODI score was observed in 62% (95% CI 38% to 82%) and 44% (95% CI 22% to 69%) of participants in the C-RFA and T-RFA groups, respectively (p=0.21).

CONCLUSIONS

When using a single diagnostic block paradigm with a threshold of >75% pain reduction, both treatment with both C-RFA and T-RFA resulted in a success rate of approximately 50% when defined by both improvement in pain and physical function at 6-month follow-up. While the success rate was higher in the C-RFA group, this difference was not statistically significant.

TRIAL REGISTRATION NUMBER

NCT02478437.

Relationship between paravertebral muscle twitching and long-term effects of radiofrequency medial branch neurotomy

Background

To achieve a prolonged therapeutic effect in patients with lumbar facet joint syndrome, radiofrequency medial branch neurotomy (RF-MB) is commonly performed. The purpose of this study was to evaluate the prognostic value of paravertebral muscle twitching when performing RF-MB in patients with lumbar facet joint syndrome.

Methods

We collected and analyzed data from 68 patients with confirmed facet joint syndrome. Sensory stimulation was performed at 50 Hz with a 0.5 V cut-off value. Patients were divided into 3 groups according to the twitching of the paravertebral muscle during 2 Hz motor stimulation: ‘Complete’, when twitching was observed at all needles; ‘Partial’, when twitching was present at 1 or 2 needles; and ‘None’, when no twitching was observed. The relationship between the long-term effects of RF-MB and paravertebral muscle twitching was analyzed.

Results

The mean effect duration of RF-MB was 4.6, 5.8, and 7.0 months in the None, Partial, and Complete groups, respectively (P = 0.47). Although the mean effect duration of RF-MB did not increase significantly in proportion to the paravertebral muscle twitching, the Complete group had prolonged effect duration (> 6 months) than the None group in subgroup analysis. (P = 0.03).

Conclusions

Paravertebral muscle twitching while performing lumbar RF-MB may be a reliable predictor of long-term efficacy when sensory provocation under 0.5 V is achieved. However, further investigation may be necessary for clarifying its clinical significance.

Optimal Temperature for Radiofrequency Ablation of Lumbar Medial Branches for Treatment of Facet-Mediated Back Pain

BACKGROUND

Radiofrequency ablation (RFA) of the medial branch nerves that innervate the facet joints is a well-established treatment modality; however, studies to determine the optimal radiofrequency ablation temperature are lacking. A wide range (70 to 90°C) has been used. This study aimed to compare outcomes with two set temperatures for the lumbar facet medial branch ablation, 90 and 80°C.

METHODS

This retrospective study compared the degree of patient self-reported functional improvement relief, postoperative opioid dose changes, as well as duration among lumbar facet medial branch (RFA) patients who had the procedures performed at 80 or 90°C.

RESULTS

Patients who underwent the procedure at 90°C had 3.1 (95% CI 1.7, 6.5) times the odds (P = 0.0004) of reporting functional improvement of at least 50% when compared to those who underwent neurotomy at 80°C. For self-reported functional improvement greater or equal to 75%, the results were sustained with an odds ratio of 2.8 (95% CI 1.2, 5.7) favoring those with 90°C temperature neurotomy (P = 0.002).

CONCLUSION

There seems to be significant functional improvement associated with temp of 90°C compared to 80°C, with no added risk of complications. Randomized controlled studies are warranted.

Radiofrequency for the Treatment of Lumbar Radicular Pain: Impact on Surgical Indications

Study Design. Quasiexperimental study. Objective. To investigate whether radiofrequency treatment can preclude the need for spinal surgery in both the short term and long term. Background. Radiofrequency is commonly used to treat lumbosacral radicular pain. Only few studies have evaluated its effects on surgical indications. Methods. We conducted a quasiexperimental study of 43 patients who had been scheduled for spinal surgery. Radiofrequency was indicated for 25 patients. The primary endpoint was the decision of the patient to reject spinal surgery 1 month and 1 year after treatment (pulsed radiofrequency of dorsal root ganglion, 76%; conventional radiofrequency of the medial branch, 12%; combined technique, 12%). The primary endpoint was the decision of the patient to reject spinal surgery 1 month and 1 year after treatment. In addition, we also evaluated adverse effects, ODI, NRS. Results. We observed after treatment with radiofrequency 80% of patients rejected spinal surgery in the short term and 76% in the long term. We conclude that radiofrequency is a useful treatment strategy that can achieve very similar outcomes to spinal surgery. Patients also reported a very high level of satisfaction (84% satisfied/very satisfied). We also found that optimization of the electrical parameters of the radiofrequency improved the outcome of this technique.

Interventional therapies for chronic low back pain

OBJECTIVE

Low back pain (LBP) is a highly prevalent condition and one of the leading causes of lost productivity and health-care costs. The objective of this review is to discuss the role of interventional pain procedures and evidence of their effectiveness in treatment of chronic LBP.

METHODS

This is a narrative review examining published studies on interventional procedures for LBP. The rationales, indications, technique, evidence, and complications for the interventional procedures are discussed.

RESULTS

Interventional pain procedures are used extensively in diagnosis and treatment of chronic pain. LBP is multifactorial, and while significant progress has been made in understanding its pathophysiology, this has not resulted in a proportional improvement of functional outcomes. For certain procedures, such as spinal cord stimulation, medical branch blocks and radiofrequency ablations, and epidural steroid injections for radiculopathy, safety, efficacy, and cost-effectiveness in treating LBP have been well studied. For others, such as interventions for discogenic pain, treatment successes have been modest at best.

CONCLUSIONS

Implementation of interventional pain procedures in the treatment framework of LBP has resulted in improvement of pain intensity in at least the short and medium terms, but equivocal results have been observed in functional improvement.

Relationship between Sensory Stimulation and Side Effects in Percutaneous Radiofrequency Treatment of the Trigeminal Ganglion

INTRODUCTION

The objective of this study was to determine the efficacy of percutaneous radiofrequency (RF) treatment of the trigeminal ganglion for treating patients with trigeminal neuralgia, to determine which patients have a long-term benefit, and to evaluate the effect of RF parameters.

METHODS

A retrospective study in 28 consecutive patients in combination with a follow-up questionnaire (n = 26, 93% response).

RESULTS

An initial treatment effect of 89% was observed, 60% sustained at 12-month follow-up. Major side effects were hypesthesia (56%), dry eye (20%), and masseter muscle weakness (12%). A lower sensory stimulation threshold during treatment was associated with better patient satisfaction (P = 0.016), improved pain relief (P = 0.039), and trended toward more hypesthesia (P = 0.077).

DISCUSSION

This low-volume study reported treatment effects in an older population that were similar to previous studies. Only a higher incidence of hypesthesia was detected by long-term follow-up. This study supported the high efficiency of RF treatment, but there was a high level of side effects. Most notable, low sensory stimulation was associated with increased hypesthesia, whereas higher stimulation levels yielded less effectiveness. Further investigation of an optimal sensory stimulation range for percutaneous RF treatment of the trigeminal ganglion was found to be warranted.