Pain Relief With Intraarticular or Medial Branch Nerve Blocks in Patients With Positive Lumbar Facet Joint SPECT Imaging: A 12-Week Outcome Study:

Comparing the clinical outcomes of lumbar transforaminal vs interlaminar epidural steroid injections in a registry cohort

Background

Transforaminal and interlaminar approaches are both common means of performing epidural steroid injection. Comparative effectiveness data on outcomes of these approaches is available but has yielded mixed results.

Objective

Compare the effect of transforaminal vs interlaminar delivery of epidural steroids on patient-reported pain severity.

Design

Retrospective Cohort Study.

Methods

A retrospective review of prospectively collected interventional spine procedure registry data between December 2011 and July 2017 from a single academic medical center. Those who received epidural steroid injections and had prospectively collected index pain data (11-point Numeric Rating Scale [NRS]) recorded in the patient's chart prior to the procedure and at a 3 month follow up appointment were included. The outcome of interest was ≥50% reduction in pain as measured using a NRS for back and/or leg pain. To evaluate true predictive odds of success, multivariable logistic regression modeling was used to determine the odds of achieving improved pain.

Results

Of the 73 patients included in the study, 61 (84%) reported radicular pain, 49 (67%) reported back pain, and eleven (15%) had symptoms consistent with claudication, pain characteristics were not mutually exclusive. Fifty-one (70%) underwent transforaminal epidural steroid injection, while 22 (30%) underwent interlaminar injection. When claudication and radicular pain groups were combined into a single "leg pain" category (n = 66), 26/46 (57% 95% CI 41-71%) patients undergoing transforaminal and 6/20 (30% 95% CI 12-54%) patients undergoing interlaminar injections achieved ≥50% leg pain reduction on NRS (p = 0.048). Transforaminal epidural steroid injections were associated with higher odds of ≥50% reduction in leg pain in both the unadjusted model (OR 3.2, p = 00.034) and after adjustment for presence of radicular pain on presentation and the type of steroid used (OR 3.6, p = 0.042).

Conclusion

In this clinical practice registry, patients treated with transforaminal epidural steroid injection were more likely to achieve ≥50% reduction in radicular or neurogenic/claudicatory leg pain compared to those treated with interlaminar epidural steroid injection.

Correlating SPECT-CT activity in lumbar facet joints with response to lumbar medial branch and L5 dorsal ramus blocks

Introduction

Lumbar facet arthritis is a significant source of back pain and impaired function that is amenable to treatment with medial branch radiofrequency neurotomy (RFN). Identifying appropriate patients for this treatment requires integration of information from the history, physical exam, and diagnostic imaging, but the current diagnostic standard for facet-mediated pain is positive comparative medial branch blocks (MBBs). Lumbar SPECT-CT has recently been evaluated as a potential predictor of positive MBBs with mixed results. The purpose of this retrospective analysis was to determine if the level of concordance between SPECT-CT uptake and facet joints targeted with MBB was associated with a positive block.

Methods

A retrospective review was performed to identify all patients undergoing lumbar MBB within 12 months after having a lumbar SPECT-CT. Each procedure was classified into one of four categories based on the level of concordance between facet joints demonstrating increased 99mTc uptake on SPECT-CT and those being blocked: 1) Complete Concordance (all joints demonstrating increased uptake were blocked and no additional joints blocked); 2) Partial Concordance (all joints demonstrating increased uptake were blocked, with at least one joint not demonstrating increased uptake blocked); 3) Partial Discordance (at least one but not all joints demonstrating increased uptake were blocked); 4) Complete Discordance (all blocks performed at joints not demonstrating increased uptake). Statistical analysis was performed to determine if the level of concordance between increased uptake on SPECT-CT and joints undergoing MBB was associated with a positive block using cutoffs of 50 % and 80 % pain relief.

Results

A total of 180 procedures were analyzed (23 % Complete Concordance, 22 % Partial Concordance, 31 % Partial Discordance, 24 % Complete Discordance) and all groups demonstrated improvement in pain Numeric Rating Scale (NRS) scores. There was no significant association between level of concordance and having a positive block using thresholds of 50 % pain relief, χ 2(3, N = 180) = 4.880, p = .181; or 80 % pain relief, χ 2(3, N = 180) = 1.272, p = .736.

Conclusion

SPECT-CT findings do not accurately predict positive lumbar MBB but may provide valuable information that can be considered with other factors when deciding which joints to treat.

[Lumbar Facet Joint Injection: A Review of Efficacy and Safety]

Facet joint arthrosis is a progressive degenerative disease that is frequently associated with other spinal degenerative disorders such as degenerative disc disease or spinal stenosis. Lumbar facet joint arthrosis can induce pain in the proximal lower extremities. However, symptoms and imaging findings of "facet joint syndrome" are not specific as they mimic the pain from herniated discs or nerve root compression. Currently, evidence for therapeutic intra-articular lumbar facet joint injections is still considered low, with a weak recommendation strength. Nevertheless, some studies have reported therapeutic effectiveness of facet joint injections. Moreover, the use of therapeutic facet joint injections in clinical practice has increased. This review article includes opinions based on the authors' experience with facet joint injections. This review primarily aimed to investigate the efficacy of lumbar facet joint injections and consider their associated safety aspects.

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.

A pragmatic randomized prospective trial of cooled radiofrequency ablation of the medial branch nerves versus facet joint injection of corticosteroid for the treatment of lumbar facet syndrome: 12 month outcomes

BACKGROUND

Lumbar medial branch radiofrequency ablation (LRFA) and intraarticular facet steroid injections (FJI) are commonly performed for recalcitrant facet joint-mediated pain. However, no study has compared clinical outcomes of the two treatments in patients selected using dual medial branch blocks (MBBs) with an 80% relief threshold.

OBJECTIVE

Compare the effectiveness of cooled LRFA (C-LRFA) to FIJ as assessed by pain and functional improvements.

DESIGN

Prospective randomized comparative trial.

METHODS

Patients with dual MBB-confirmed facet joint-mediated pain were randomized to receive C-LRFA or FIJ. Outcomes were assessed at 1, 3, 6, and 12 months. The primary outcome was ≥50% improvement in numerical pain rating scale (NPRS) score at 3 months. Secondary outcomes included ≥30% Oswestry Disability Index (ODI) improvement and Patient Global Impression of Chance (PGIC) ≥6 points, among others. Data were analyzed using contingency tables and mixed-effects logistic regression models.

RESULTS

Of 1128 patients screened, 32 met eligibility criteria, were randomized, and received their allocated study treatment. In total, 20 (62.5%) and 12 (37.5%) participants received C-LRFA and FIJ, respectively. In the C-LRFA group, 70% (95% CI 48-85), 55% (95% CI 34-74), and 45% (95% CI 26-66) of participants met the NPRS responder definition, compared to 25% (95%CI 9-53), 25% (95% CI 9-53), and 17% (95% CI 5-45) in the FJI group at 3, 6, and 12 months, respectively (P = .014 at 3 months). The PGIC responder proportion was higher in the C-LRFA compared to FJI group at 3 and 6 months (P < .05).

CONCLUSIONS

C-LRFA demonstrated superior success rates compared to FJI across pain and functional outcome domains.

TRIAL REGISTRATION DETAILS

ClinicalTrials.gov (NCT03614793); August 3, 2018.

Comparative Evaluation of Intraarticular Facet Joint Injection Versus Medial Branch Block in Patients With Low Back Pain: A Randomised Controlled Study

INTRODUCTION

Lumbar facet joint pain may refer to the back, buttocks, and proximal parts of the lower extremities. Intraarticular facet joint injections, facet joint nerve blocks, or facet joint neurolytic procedures are popular for the management of facet joint pain.

MATERIAL AND METHODS

In this prospective, randomised study, 60 patients with a medical evaluation and pain pattern consistent with lumbar facet joint pain were randomly allocated to two groups. Group Ⅰ (n=30) patients were administered fluoroscope-guided lumbar facet joint injection, and group Ⅱ (n=30) patients were administered fluoroscope-guided lumbar facet joint nerve block. The primary objective is to compare the efficacy of both in managing facet joint pain in terms of pain and disability improvement. Secondary objectives were to compare the requirement for repeat injections and parameters related to the block, such as ease of administering the block, and to note the side effects pertaining to either of the blocks.

RESULTS

There was a statistically significant improvement in pain score after injection in both groups (p>0.05). The mean pain score in both groups remained less than two at all time intervals throughout the study period (p>0.05) Excellent patient satisfaction was reported by the majority of the patients at different time intervals in both groups.

CONCLUSION

Both lumbar facet joint injection and lumbar facet joint nerve block are safe and effective techniques for managing lower back pain patients. Both techniques provide adequate pain relief and disability improvement.

Image-Guided Spine Interventions for Pain: Ongoing Controversies

An expanding array of image-guided spine interventions have the potential to provide immediate and effective pain relief. Innovations in spine intervention have proceeded rapidly, with clinical adoption of new techniques at times occurring before the development of bodies of evidence to establish efficacy. Although new spine interventions have been evaluated by clinical trials, acceptance of results has been hindered by controversies regarding trial methodology. This article explores controversial aspects of four categories of image-guided interventions for painful conditions: spine interventions for postdural puncture headache resulting from prior lumbar procedures, epidural steroid injections for cervical and lumbar radiculopathy, interventions for facet and sacroiliac joint pain, and vertebral augmentations for compression fractures. For each intervention, we summarize the available literature, with an emphasis on persistent controversies, and discuss how current areas of disagreement and challenge may shape future research and innovation. Despite the ongoing areas of debate regarding various aspects of these procedures, effective treatments continue to emerge and show promise for aiding relief of a range of debilitating conditions.

SPECT-CT as a Predictor of Pain Generators in Patients Undergoing Intra-Articular Injections for Chronic Neck and Back Pain

BACKGROUND

The ability to accurately predict pain generators for chronic neck and back pain remains elusive.

OBJECTIVE

We evaluated whether injections targeted at foci with uptake on single-photon emission computerized tomography-computed tomography (SPECT-CT) were associated with improved outcomes in patients with chronic neck and back pain.

METHODS

A retrospective review was completed on patients undergoing SPECT-CT for chronic neck and back pain between 2016 and 2020 at a tertiary academic center. Patients' records were reviewed for demographic, clinical, imaging, and outcomes data. Only those patients who had facet injections after SPECT-CT were included in this evaluation. Patients undergoing injections targeted at foci of abnormal radiotracer uptake were compared with patients without uptake concerning immediate positive response, visual analog scale, and the need for additional injection or surgery at the target level.

RESULTS

A total of 2849 patients were evaluated with a SPECT-CT for chronic neck and back pain. Of those, 340 (11.9%) patients received facet joint injections after SPECT-CT. A propensity score regression analysis adjusted for age, gender, body mass index, hypertension, multiple target injections, and injection location showed uptake targeted injections not being associated with an improved immediate positive response (odds ratio: 0.64; 95% confidence interval: 0.34-1.21; P = 0.172). In patients with a failed facet injection preceding SPECT-CT, adding SPECT-CT to guide facet injections was associated with a decrease in visual analog scale pain scores 2 weeks after injection (P = 0.018), particularly when changes were made to the facets being targeted (P = 0.010).

CONCLUSION

This study suggests that there is benefit with SPECT-CT specially to guide facet injections after failed prior facet injections.

Predictors of response to medial branch block, radiofrequency ablation or facet joint injections: a retrospective study

Aim: Low back pain is a leading cause of patient disability in the USA. Our goal was to determine association between patient characteristics and their response to lumbar medial branch block, radiofrequency ablation of medial nerves or lumbar facet joint injections. Materials & methods: Medical records for the first 100 patients who underwent lumbar medial branch block, radiofrequency ablation of lumbar medial nerves or lumbar facet joint injections between 1 September 2019 and 31 March 2020 were reviewed and demographic data were recorded. Results: At the 3-month post-procedure visit, positive responders were significantly more likely to be non obese patients (BMI <30) and those with pain <5-years. Conclusion: Obesity and chronicity of pain certainly are found to be predictors of response to the above mentioned procedures.

Therapeutic Facet Joint Interventions in the Lumbar Spine: An Economic Value Perspective

OBJECTIVE

In this narrative review, the current literature on therapeutic interventions for low back pain of facet joint etiology is assessed from an economic value perspective.

SUMMARY OF BACKGROUND DATA

The efficacy and economics of facet joint interventions in the treatment of lumbar back pain is a controversial topic. Trends show that facet joint interventions are becoming increasingly used, perhaps as physicians become more averse to treating chronic low back pain with opioids. With the emphasis on value-based spine care and changing reimbursement models, the perspective of rigorously evaluating the outcomes these interventions provide and the costs they incur is particularly relevant.

DISCUSSION

Although the evidence is noted to be limited, most systematic reviews fail to demonstrate the therapeutic utility of intra-articular facet joint injections in low back pain because of high study heterogeneity. A few good quality studies and systematic reviews describe moderate evidence for the utilization of therapeutic medial branch blocks and radiofrequency neurotomies in alleviating facet joint pain.

CONCLUSION

Consequently, there is a need for high-quality cost-effectiveness studies for facet joint interventions so that evidence-based and economically viable solutions can be used to optimize patient care at a societally affordable price.

Guideline summary review: an evidence-based clinical guideline for the diagnosis and treatment of low back pain

BACKGROUND CONTEXT

The North American Spine Society's (NASS) Evidence Based Clinical Guideline for the Diagnosis and Treatment of Low Back Pain features evidence-based recommendations for diagnosing and treating adult patients with nonspecific low back pain. The guideline is intended to reflect contemporary treatment concepts for nonspecific low back pain as reflected in the highest quality clinical literature available on this subject as of February 2016.

PURPOSE

The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with nonspecific low back pain. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition.

STUDY DESIGN

This is a guideline summary review.

METHODS

This guideline is the product of the Low Back Pain Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guideline was submitted to an internal and external peer review process and ultimately approved by the NASS Board of Directors.

RESULTS

Eighty-two clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature.

CONCLUSIONS

The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with nonspecific low back pain. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx.

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.

Intra-articular Steroids vs Saline for Lumbar Z-Joint Pain: A Prospective, Randomized, Double-Blind Placebo-Controlled Trial

OBJECTIVE

To determine if intra-articular (IA) injection of corticosteroids is effective in reducing the need for radiofrequency ablation (RFA) in those with dual comparative medial branch block (MBB)-confirmed lumbar z-joint pain.

DESIGN

This was a randomized, double blind, placebo-controlled study.

SETTING

Two academic medical centers.

SUBJECTS

Fifty-six consecutive subjects who had ≥80% pain relief during an initial screening MBB were recruited.

METHODS

Patients received a second confirmatory MBB and concurrent IA injection of either corticosteroid or saline per randomization. Twenty-nine of 56 received intra-articular corticosteroid (triamcinolone 20 mg), of whom 24 also had a positive confirmatory MBB per Spine Interventional Society guidelines, with ≥80% pain relief from both MBBs. Twenty-seven of 56 received IA saline into the z-joint during the confirmatory MBB, of whom 22 also had a positive confirmatory MBB. The primary outcome measure was the categorical need for RFA due to insufficient pain relief with intra-articular injection, and the secondary outcome was time to RFA.

RESULTS

There was no statistically significant difference in the need for an RFA between the groups (16/24 steroid, 67%, 95% confidence interval [CI] = 47-82%) vs 15/22 saline (68%, 95% CI = 47-84%, P = 1.00). The average time to RFA was also not different, at 6.00 weeks for steroids vs 6.55 weeks for saline (P = 0.82).

CONCLUSIONS

Intra-articular corticosteroids were not effective in reducing the need for or the time to a radiofrequency ablation of the medial branches in those with dual MBB-confirmed lumbar z-joint pain.

Diagnostic Value of Single-Photon Emission Computed Tomography/Computed Tomography Scans with Tc-99m HDP in Cervicogenic Headache

A cervicogenic headache (CEH) is difficult to diagnose due to its varied pathology. We evaluated the usefulness of single-photon emission computed tomography/computed tomography (SPECT/CT) in diagnosing CEH and its interventional treatment. Retrospectively, 23 patients diagnosed with CEH between March 2016 to August 2018 were allocated to SPECT/CT (n = 11) and control (n = 12) groups. The SPECT/CT group was further stratified into SPECT/CT(+) and SPECT/CT(-) groups according to the presence of positive findings. Patients in the SPECT/CT group underwent an intra-articular injection at a radiologically verified lesion site, whereas those in the control group underwent third occipital nerve block. Clinical outcomes were evaluated with the visual analog scale (VAS), neck disability index (NDI), and global perceived effect (GPE) scale at baseline, and at one, three, and six months postoperatively. The SPECT/CT group showed less VAS, NDI, and GPE scores at six months postoperatively (2.91 ± 2.30 vs. 4.42 ± 1.62, p = 0.08; 38.00 ± 16.54 vs. 48.7 ± 12.40, p = 0.093; 2.00 ± 1.41 vs. 3.17 ± 1.11, p = 0.039). Successful responders at six months postoperatively were higher in the SPECT/CT(+) group than in the control group (75% vs. 0%). SPECT/CT can identify arthritic changes and accurately define therapeutic targets.

Corticosteroid Injections Into Lumbar Facet Joints: A Prospective, Randomized, Double-Blind Placebo-Controlled Trial

BACKGROUND

Corticosteroid injections into the intra-articular zygapophysial (z-joints) are frequently used to treat this cause of low back pain. No studies have been done on the efficacy of intra-articular corticosteroids in those with z-joint pain confirmed by dual comparative medial branch blocks.

OBJECTIVE

The aim of the study was to determine whether an injection of a corticosteroid into lumbar z-joints is effective in reducing pain and the need for radiofrequency neurotomy.

METHODS

This is a double-blind, prospective, randomized, placebo-controlled trial. The study was conducted in Academic Medical Center. Twenty-eight subjects with z-joint pain confirmed by medial branch blocks were included in the study. Subjects with confirmed z-joint pain via dual comparative medial branch block were randomized to receive either intra-articular corticosteroid (triamcinolone 20 mg) or saline via fluoroscopic guided injection.

RESULTS

No statistically significant difference in the need for radiofrequency neurotomy (radiofrequency neurotomy) between the groups, with 75% (95% confidence interval = 50.5%-99.5%) of the saline group vs. 91% (95% confidence interval = 62.3%-100%) of the corticosteroid group receiving radiofrequency neurotomy. There is no difference in mean time to radiofrequency neurotomy between saline (6.1 wks) and corticosteroid (6.5 wks) groups. There is a need for radiofrequency neurotomy.

CONCLUSIONS

Corticosteroid injections into the lumbar z-joints were not effective in reducing the need for radiofrequency neurotomy of the medial branches in those with z-joint pain confirmed by dual comparative medial branch blocks.

Predictors of Response to a Medial Branch Block: MRI Analysis of the Lumbar Spine

The aim of this study was to determine the association between radiologic spinal pathology and the response to medial branches block (MBB). This retrospective observational study compared 165 patients. A successful response was defined as ≥30% or a 2-point reduction in the numeric rating scale (NRS) compared with the baseline at the 1-month follow-up. The facet angle, facet angle difference, facet joint degeneration, disc height and spondylolisthesis grade were analyzed from an MRI at the L3 to S1 levels. Univariate and multivariate logistic regression analyses were used to evaluate independent factors associated with a successful response of MBB. In the univariate analysis, the disc height at L5-S1 and facet angle difference at L3-4 were lower in the positive responders (p = 0.022 and p = 0.087, respectively). In the multivariate analysis, the facet angle difference at L3-4 and disc height at L5-S1 were independent factors associated with a successful response (odds ratio = 0.948; p = 0.038 and odds ratio = 0.864; p = 0.038, respectively). In patients with a degenerative disc at L5-S1, MBB can lead to a good response for at least one month. In patients with facet tropism at L3-4 level, the response to MBB after one month is likely to be poor.

Effectiveness of Lumbar Facet Joint Blocks and Predictive Value before Radiofrequency Denervation: The Facet Treatment Study (FACTS), a Randomized, Controlled Clinical Trial

WHAT WE ALREADY KNOW ABOUT THIS TOPIC

WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: With facet interventions under scrutiny, the authors' objectives were to determine the effectiveness of different lumbar facet blocks and their ability to predict radiofrequency ablation outcomes.

METHODS

A total of 229 participants were randomized in a 2:2:1 ratio to receive intraarticular facet injections with bupivacaine and steroid, medial branch blocks, or saline. Those with a positive 1-month outcome (a 2-point or more reduction in average pain score) and score higher than 3 (positive satisfaction) on a 5-point satisfaction scale were followed up to 6 months. Participants in the intraarticular and medial branch block groups with a positive diagnostic block (50% or more relief) who experienced a negative outcome proceeded to the second phase and underwent radiofrequency ablation, while all saline group individuals underwent ablation. Coprimary outcome measures were average reduction in numerical rating scale pain score 1 month after the facet or saline blocks, and average numerical rating scale pain score 3 months after ablation.

RESULTS

Mean reduction in average numerical rating scale pain score at 1 month was 0.7 ± 1.6 in the intraarticular group, 0.7 ± 1.8 in the medial branch block group, and 0.7 ± 1.5 in the placebo group; P = 0.993. The proportions of positive blocks were higher in the intraarticular (54%) and medial branch (55%) groups than in the placebo group (30%; P = 0.01). Radiofrequency ablation was performed on 135 patients (45, 48, and 42 patients from the intraarticular, medial branch, and saline groups, respectively). The average numerical rating scale pain score at 3 months was 3.0 ± 2.0 in the intraarticular, 3.2 ± 2.5 in the medial branch, and 3.5 ± 1.9 in the control group (P = 0.493). At 3 months, the proportions of positive responders in the intraarticular, medial branch block, and placebo groups were 51%, 56%, and 24% for the intraarticular, medial branch, and placebo groups, respectively (P = 0.005).

CONCLUSIONS

This study establishes that facet blocks are not therapeutic. The higher responder rates in the treatment groups suggest a hypothesis that facet blocks might provide prognostic value before radiofrequency ablation.

Toward a Mechanism-Based Approach to Pain Diagnosis

The past few decades have witnessed a huge leap forward in our understanding of the mechanistic underpinnings of pain, in normal states where it helps protect from injury, and also in pathological states where pain evolves from a symptom reflecting tissue injury to become the disease itself. However, despite these scientific advances, chronic pain remains extremely challenging to manage clinically. Although the number of potential treatment targets has grown substantially and a strong case has been made for a mechanism-based and individualized approach to pain therapy, arguably clinicians are not much more advanced now than 20 years ago, in their capacity to either diagnose or effectively treat their patients. The gulf between pain research and pain management is as wide as ever. We are still currently unable to apply an evidence-based approach to chronic pain management that reflects mechanistic understanding, and instead, clinical practice remains an empirical and often unsatisfactory journey for patients, whose individual response to treatment cannot be predicted. In this article we take a common and difficult to treat pain condition, chronic low back pain, and use its presentation in clinical practice as a framework to highlight what is known about pathophysiological pain mechanisms and how we could potentially detect these to drive rational treatment choice. We discuss how present methods of assessment and management still fall well short, however, of any mechanism-based or precision medicine approach. Nevertheless, substantial improvements in chronic pain management could be possible if a more strategic and coordinated approach were to evolve, one designed to identify the specific mechanisms driving the presenting pain phenotype. We present an analysis of such an approach, highlighting the major problems in identifying mechanisms in patients, and develop a framework for a pain diagnostic ladder that may prove useful in the future, consisting of successive identification of 3 steps: pain state, pain mechanism, and molecular target. Such an approach could serve as the foundation for a new era of individualized/precision pain medicine. The Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION)-American Pain Society (APS) Pain Taxonomy (AAPT) includes pain mechanisms as 1 of the 5 dimensions that need to be considered when making a diagnostic classification. The diagnostic ladder proposed in this article is consistent with and an extension of the AAPT.

PERSPECTIVE

We discuss how identifying the specific mechanisms that operate in the nervous system to produce chronic pain in individual patients could provide the basis for a targeted and rational precision medicine approach to controlling pain, using chronic low back pain as our example.

Medial Branch Blocks or Intra-Articular Injections as a Prognostic Tool Before Lumbar Facet Radiofrequency Denervation: A Multicenter, Case-Control Study

BACKGROUND

Medial branch blocks (MBBs) and intra-articular (IA) facet joint injections are both used to diagnose facet joint pain and are presumed to be equivalent. No study has sought to determine which has a better prognostic value before radiofrequency (RF) denervation.

METHODS

A case-control study was performed at 4 institutions in which RF denervation outcomes in patients who obtained 50% or more pain relief from either MBB (n = 212) or IA injections (n = 212) were compared. "Control" patients (MBB) were matched to "cases" by treating physician, last name, and date of treatments. During data mining, 87 patients were identified who underwent RF ablation after receiving both IA injections and MBB and were used for secondary analyses.

RESULTS

A total of 70.3% of MBB patients experienced 50% or more pain relief at the 3-month follow-up versus 60.8% in those who underwent IA injections (P = 0.041). In multivariable analysis, undergoing MBB was associated with RF treatment success (odds ratio [OR], 1.57; 95% confidence interval [95% CI], 1.0-2.39; P = 0.036), whereas opioid use (OR, 0.52; 95% CI, 0.34-0.79; P = 0.002) and previous back surgery (OR, 0.60; 95% CI, 0.38-0.95; P = 0.028) were associated with treatment failure. No significant differences were noted between MBB alone and combination treatment or single versus multiple blocks. In the secondary multivariable analysis including the combination IA + MBB group, MBB alone was again independently associated with an RF ablation treatment success (OR, 1.73; 95% CI, 1.12-2.67; P = 0.014).

CONCLUSIONS

When used as a prognostic tool before lumbar facet radiofrequency, MBB may be associated with a higher success rate than IA injections. Our results should be confirmed by large, prospective, randomized studies.

The effect of journal impact factor, reporting conflicts, and reporting funding sources, on standardized effect sizes in back pain trials: a systematic review and meta-regression

BACKGROUND

Low back pain is a common and costly health complaint for which there are several moderately effective treatments. In some fields there is evidence that funder and financial conflicts are associated with trial outcomes. It is not clear whether effect sizes in back pain trials relate to journal impact factor, reporting conflicts of interest, or reporting funding.

METHODS

We performed a systematic review of English-language papers reporting randomised controlled trials of treatments for non-specific low back pain, published between 2006-2012. We modelled the relationship using 5-year journal impact factor, and categories of reported of conflicts of interest, and categories of reported funding (reported none and reported some, compared to not reporting these) using meta-regression, adjusting for sample size, and publication year. We also considered whether impact factor could be predicted by the direction of outcome, or trial sample size.

RESULTS

We could abstract data to calculate effect size in 99 of 146 trials that met our inclusion criteria. Effect size is not associated with impact factor, reporting of funding source, or reporting of conflicts of interest. However, explicitly reporting 'no trial funding' is strongly associated with larger absolute values of effect size (adjusted β=1.02 (95 % CI 0.44 to 1.59), P=0.001). Impact factor increases by 0.008 (0.004 to 0.012) per unit increase in trial sample size (P<0.001), but does not differ by reported direction of the LBP trial outcome (P=0.270).

CONCLUSIONS

The absence of associations between effect size and impact factor, reporting sources of funding, and conflicts of interest reflects positively on research and publisher conduct in the field. Strong evidence of a large association between absolute magnitude of effect size and explicit reporting of 'no funding' suggests authors of unfunded trials are likely to report larger effect sizes, notwithstanding direction. This could relate in part to quality, resources, and/or how pragmatic a trial is.

Correlation of (99m) Tc-DPD SPECT/CT Scan Findings and Diagnostic Blockades of Lumbar Medial Branches in Patients with Unspecific Low Back Pain in a Randomized-Controlled Trial

OBJECTIVE

Zygapophyseal joints are the origin of pain in up to 30% of those with unspecific chronic low back pain. Until recently, no reliable clinical tests have been found to identify the patients who would benefit from denervation of the zygapophyseal joints by medial branch blockades.

DESIGN

We performed a prospective randomized placebo-controlled trial to evaluate the value of high-resolution single-photon emission computed tomography (SPECT)/computed tomography (CT) of the lumbar spine prior to any diagnostic infiltration of the medial branches.

METHODS

Patients with suspected zygapophyseal joint-related pain were included in the study. After obtaining a SPECT/CT scan of the lumbar spine a set of infiltrations of the medial branches was done with local anesthetics and placebo on different days. Patients and anesthetists were blinded to the results of SPECT/CT and to the infiltrated agents.

RESULTS

In a total of 29 study patients, 7 had positive and 22 negative infiltration tests, and 9 had positive and 20 negative SPECT/CT findings. Sensitivity of SPECT/CT for a positive response after diagnostic infiltration was 0.57 (95% confidence interval [CI] 0.18-0.90); specificity was 0.77 (CI 95% 0.55-0.92); odds ratio was 4.53 (CI 95% 0.75-27.40); and diagnostic accuracy was 0.72.

CONCLUSION

Compared with diagnostic infiltrations SPECT/CT scans showed only a moderate sensitivity and specificity and, therefore, may not be recommended as a first line diagnostic tool prior to diagnostic infiltrations.

Single photon emission computerized tomography (SPECT) scan-positive facet joints and other spinal structures in a hospital-wide population with spinal pain

BACKGROUND CONTEXT

The current criterion standard for zygapophyseal (facet) joint pain diagnosis is placebo-controlled triple comparative local anesthetic facet joint or medial branch blocks. Single photon emission computerized tomography (SPECT) scanning is a less invasive modality that has been widely used in patients with spinal pain for the diagnosis of facet joint arthritis. Previous studies have shown that SPECT results correlate well with response to facet joints steroid injections.

PURPOSE

To evaluate the prevalence of SPECT scan-positive facet joints and other spinal areas in different age groups in a hospital-wide population with spinal pain.

STUDY DESIGN

Retrospective study.

METHODS

This study included 534 patients who underwent a SPECT scan for spinal pain over 7.5 years in our hospital. All referrals from all doctors for any cervical or lumbar spinal pain were included, and the results were reviewed.

RESULTS

A total of 486 patients (91.1%) had at least one positive abnormality on SPECT scan; 81.3% had increased uptake in different structures and regions of the spine. This included 42.8% increased uptake in the facet joint 29.8% in the vertebral bodies/end plates, and 5.9% in sacroiliac joints. The prevalence of increased uptake in the lumbosacral and cervical spine was 44% and 37%, respectively. When patients were divided into five age groups (below 40, 40-49, 50-59, 60-69, and 70 years and older), there was a significantly higher increased prevalence in advancing age groups.

CONCLUSIONS

In a hospital-wide population with spinal pain, there is a 42.88% prevalence of increased uptake in the facet joint on SPECT. The incidence increases significantly with advancing age. SPECT can play a role in investigating patients with spinal pain.