Prognostic value of hypersensitivity reactions on epidural steroid injection outcomes: a phenotypic signature? A prospective cohort study.

BACKGROUND: Studies have found that diffuse pain, indicative of central sensitization, portends poor interventional outcomes. Multiple chemical sensitivities are associated with signs of central sensitization. We sought to prospectively determine whether hypersensitivity reactions (HR) were associated with epidural steroid injection (ESI) outcomes. METHODS: HR were classified as immune-related or non-immune-related and categorized by number (0=low, 1 or 2=intermediate, ≥3=high). The primary outcome measure was mean reduction in average leg pain score 1 month post-procedure. A positive outcome was defined as a two-point or greater decrease in average leg pain accompanied by satisfaction 1 month post-procedure. RESULTS: The mean number of immune-mediated and non-immune-mediated HR were 0.6±1.2 and 0.8±1.4, respectively. Individuals in the high (n=24) total HR group had a mean reduction in average leg pain of 0.1±2.7, compared with those in the low (n=61; 1.8±2.1, p=0.025) and intermediate groups (n=52; 1.6±3.1, p=0.060). For back pain and categorical successful outcome, those with fewer HR experienced greater benefit. There were no differences in outcomes when patients were stratified by immune-related HR. Among participants in the low, intermediate and high non-immune-mediated HR groups, the mean reductions in average leg pain scores were 1.7±2.5, 1.6±3.0, and -0.2±2.3, respectively (p = 0.002). 51%, 35%, and 12% of people with low, intermediate and high numbers of non-immune-mediated HR experienced a positive categorical outcome, respectively (p=0.007). CONCLUSIONS: Non-immune-related HR were inversely correlated with some ESI outcome measures.

Fluoroscopically Guided vs Landmark-Guided Sacroiliac Joint Injections: A Randomized Controlled Study.

OBJECTIVES: To determine the prevalence of intra- and extra-articular sacroiliac joint (SIJ) pain, which injection is more beneficial, and whether fluoroscopy improves outcomes. PATIENTS AND METHODS: This patient- and evaluator-blinded comparative effectiveness study randomized 125 participants with SIJ pain from April 30, 2014, through December 12, 2017, to receive fluoroscopically guided injections into the joint capsule (group 1) or "blind" injections to the point of maximum tenderness using sham radiographs (group 2). The primary outcome was average pain on a 0 to 10 scale 1 month after injection. A positive outcome was defined as at least a 2-point decrease in average pain score coupled with positive (>3) satisfaction on a Likert scale from 1 to 5. RESULTS: For the primary outcome, no significant differences were observed between groups (mean ± SD change from baseline, -2.3±2.4 points in group 1 vs -1.7±2.3 points in group 2; 95% CI, -0.33 to 1.36 points for adjusted difference; P=.23), nor was there a difference in the proportions of positive blocks (61% vs 62%) or 1-month categorical outcome (48% vs 40% in groups 1 and 2, respectively; P=.33). At 3 months, the mean ± SD reductions in average pain (-1.8±2.1 vs -0.9 ± 2.0 points; 95% CI, 0.11 to 1.58 points for adjusted difference; P=.02) and worst pain (-2.2±2.5 vs -1.4±2.0 points; 95% CI, 0.01 to 1.66 points for adjusted difference; P=.049) were greater in group 1 than 2, with other outcome differences falling shy of statistical significance. CONCLUSION: Although fluoroscopically guided injections provide greater intermediate-term benefit in some patients, these differences are modest and accompanied by large cost differences. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02096653.

Compounded Topical Pain Creams to Treat Localized Chronic Pain: A Randomized Controlled Trial.

Background: The use of compounded topical pain creams has increased dramatically, yet their effectiveness has not been well evaluated. Objective: To determine the efficacy of compounded creams for chronic pain. Design: Randomized controlled trials of 3 interventions. (ClinicalTrials.gov: NCT02497066). Setting: Military treatment facility. Participants: 399 patients with localized pain classified by each patient's treating physician as neuropathic (n = 133), nociceptive (n = 133), or mixed (n = 133). Intervention: Pain creams compounded for neuropathic pain (ketamine, gabapentin, clonidine, and lidocaine), nociceptive pain (ketoprofen, baclofen, cyclobenzaprine, and lidocaine), or mixed pain (ketamine, gabapentin, diclofenac, baclofen, cyclobenzaprine, and lidocaine), or placebo. Measurements: The primary outcome measure was average pain score 1 month after treatment. A positive categorical response was a reduction in pain score of 2 or more points coupled with a score above 3 on a 5-point satisfaction scale. Secondary outcomes included Short Form-36 Health Survey scores, satisfaction, and categorical response. Participants with a positive outcome were followed through 3 months. Results: For the primary outcome, no differences were found in the mean reduction in average pain scores between the treatment and control groups for patients with neuropathic pain (-0.1 points [95% CI, -0.8 to 0.5 points]), nociceptive pain (-0.3 points [CI, -0.9 to 0.2 points]), or mixed pain (-0.3 points [CI, -0.9 to 0.2 points]), or for all patients (-0.3 points [CI, -0.6 to 0.1 points]). At 1 month, 72 participants (36%) in the treatment groups and 54 (28%) in the control group had a positive outcome (risk difference, 8% [CI, -1% to 17%]). Limitations: Generalizability is limited by heterogeneity among pain conditions and formulations of the study interventions. Randomized follow-up was only 1 month. Conclusion: Compounded pain creams were not better than placebo creams, and their higher costs compared with approved compounds should curtail routine use. Primary Funding Source: Centers for Rehabilitation Sciences Research, Defense Health Agency, U.S. Department of Defense.

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.

Acute and Chronic Pain on the Battlefield: Lessons Learned from Point of Injury to the United States.

Historically, war tends to accelerate innovation within military medicine. In this article, the authors argue this truism has recurred in the case of acute and chronic pain management for combatants in the global war on terrorism (GWOT). Advances in regional anesthesia techniques and multimodal acute pain care are highlighted in light of the typical weapons, injuries, and comorbid conditions of the modern combat era. Reported success of providing chronic pain care in the war theater during GWOT is discussed in the context of operational requirements for current and future wars. A description is provided of the Pain Management Task Force (PMTF) and Pain Campaign Plan which was initiated during GWOT. The PMTF effort enhanced pain education and clinical pain care through leadership and organizational changes, which created broader access to pain treatments for patients and more standardized treatment capabilities across the enterprise.

Epidural steroid injections compared with gabapentin for lumbosacral radicular pain: multicenter randomized double blind comparative efficacy study.

OBJECTIVE: To evaluate whether an epidural steroid injection or gabapentin is a better treatment for lumbosacral radiculopathy. DESIGN: A multicenter randomized study conducted between 2011 and 2014. Computer generated randomization was stratified by site. Patients and evaluating physicians were blinded to treatment outcomes. SETTINGS: Eight military, Veterans Administration, and civilian hospitals. PARTICIPANTS: 145 people with lumbosacral radicular pain secondary to herniated disc or spinal stenosis for less than four years in duration and in whom leg pain is as severe or more severe than back pain. INTERVENTIONS: Participants received either epidural steroid injection plus placebo pills or sham injection plus gabapentin. MAIN OUTCOME MEASURES: Average leg pain one and three months after the injection on a 0-10 numerical rating scale. A positive outcome was defined as a ≥ 2 point decrease in leg pain coupled with a positive global perceived effect. All patients had one month follow-up visits; patients whose condition improved remained blinded for their three month visit. RESULTS: There were no significant differences for the primary outcome measure at one month (mean pain score 3.3 (SD 2.6) and mean change from baseline -2.2 (SD 2.4) in epidural steroid injection group versus 3.7 (SD 2.6) and -1.7 (SD 2.6) in gabapentin group; adjusted difference 0.4, 95% confidence interval -0.3 to 1.2; P=0.25) and three months (mean pain score 3.4 (SD 2.7) and mean change from baseline -2.0 (SD 2.6) versus 3.7 (SD 2.8) and -1.6 (SD 2.7), respectively; adjusted difference 0.3, -0.5 to 1.2; P=0.43). Among secondary outcomes, one month after treatment those who received epidural steroid injection had greater reductions in worst leg pain (-3.0, SD 2.8) than those treated with gabapentin (-2.0, SD 2.9; P=0.04) and were more likely to experience a positive successful outcome (66% v 46%; number needed to treat=5.0, 95% confidence interval 2.8 to 27.0; P=0.02). At three months, there were no significant differences between treatments. CONCLUSIONS: Although epidural steroid injection might provide greater benefit than gabapentin for some outcome measures, the differences are modest and are transient for most people.Trial registration ClinicalTrials.gov Identifier: NCT01495923.

Epidural steroid injections, conservative treatment, or combination treatment for cervical radicular pain: a multicenter, randomized, comparative-effectiveness study.

BACKGROUND: Cervical radicular pain is a major cause of disability. No studies have been published comparing different types of nonsurgical therapy. METHODS: A comparative-effectiveness study was performed in 169 patients with cervical radicular pain less than 4 yr in duration. Participants received nortriptyline and/or gabapentin plus physical therapies, up to three cervical epidural steroid injections (ESI) or combination treatment over 6 months. The primary outcome measure was average arm pain on a 0 to 10 scale at 1 month. RESULTS: One-month arm pain scores were 3.5 (95% CI, 2.8 to 4.2) in the combination group, 4.2 (CI, 2.8 to 4.2) in ESI patients, and 4.3 (CI, 2.8 to 4.2) in individuals treated conservatively (P = 0.26). Combination group patients experienced a mean reduction of -3.1 (95% CI, -3.8 to -2.3) in average arm pain at 1 month versus -1.8 (CI, -2.5 to -1.2) in the conservative group and -2.0 (CI, -2.7 to -1.3) in ESI patients (P = 0.035). For neck pain, a mean reduction of -2.2 (95% CI, -3.0 to -1.5) was noted in combination patients versus -1.2 (CI, -1.9 to -0.5) in conservative group patients and -1.1 (CI, -1.8 to -0.4) in those who received ESI; P = 0.064). Three-month posttreatment, 56.9% of patients treated with combination therapy experienced a positive outcome versus 26.8% in the conservative group and 36.7% in ESI patients (P = 0.006). CONCLUSIONS: For the primary outcome measure, no significant differences were found between treatments, although combination therapy provided better improvement than stand-alone treatment on some measures. Whereas these results suggest an interdisciplinary approach to neck pain may improve outcomes, confirmatory studies are needed.

The effect of sedation on the accuracy and treatment outcomes for diagnostic injections: a randomized, controlled, crossover study.

BACKGROUND AND OBJECTIVE: Diagnostic injections are used to diagnose myriad pain conditions, but are characterized by a high false-positive rate. One potential cause of inaccurate diagnostic blocks is the use of sedation. We sought to determine the effect of sedation on the validity of diagnostic injections. DESIGN: Randomized, crossover study in which 73 patients were allocated to receive a diagnostic sacroiliac joint or sympathetic nerve block performed either with or without sedation using midazolam and fentanyl. Those who obtained equivocal relief, good relief lasting less than 3 months, or who were otherwise deemed good candidates for a repeat injection, received a subsequent crossover injection within 3 months (N = 46). SETTING AND PATIENTS: A tertiary care teaching hospital and a military treatment facility. RESULTS: In the primary crossover analysis, blocks performed with sedation resulted in a larger mean reduction in pain diary score than those done without sedation (1.2 [2.6]; P = 0.006), less procedure-related pain (difference in means 2.3 [2.5]; P < 0.0001), and a higher proportion of patients who obtained > 50% pain relief on their pain diaries (70% vs. 54%; P = 0.039). The increased pain reduction was not accompanied by increased satisfaction (sedation mean 3.9 [1.1] vs. 3.7 [1.3]; P = 0.26). Similar findings were observed for the parallel group (N = 73) and omnibus (all sedation vs. no sedation blocks, N = 110) analyses. No differences in outcomes were noted between the use and non-use of sedation at 1-month. CONCLUSIONS: The use of sedation during diagnostic injections may increase the rate of false-positive blocks and lead to misdiagnoses and unnecessary procedures, but has no effect on satisfaction or outcomes at 1-month.

Does pain score in response to a standardized subcutaneous local anesthetic injection predict epidural steroid injection outcomes in patients with lumbosacral radiculopathy? A prospective correlational study.

OBJECTIVE: Epidural steroid injections (ESI) are the most commonly performed pain procedures. Despite numerous studies, controversy continues to surround their effectiveness. The purpose of this study is to determine whether a standard, clinical local anesthetic injection can predict outcomes for ESI. STUDY DESIGN: In this multicenter study, 103 patients received two ESI 2 weeks apart. Prior to their first injection, subjects rated the pain intensity of a standardized subcutaneous (SQ) injection of lidocaine prior to the full dose. Numerical rating scale pain scores were correlated with leg and back pain relief, and functional improvement, through 3-month follow-up. OUTCOME MEASURES: A composite successful outcome was predetermined to be a ≥2-point decrease in leg pain score, coupled with a positive global perceived effect. RESULTS: A small but significant relationship was found between SQ pain score and reduction in leg (r = -0.21, 95% CI -0.38 to -0.04; P = 0.03) and back pain (r = -0.22, 95% CI -0.36 to -0.07; P = 0.03). Subjects with a positive outcome at 1 month had a mean SQ pain score of 2.5 (SD 1.9) vs 4.1 (SD 2.7) in those with a negative outcome (P = 0.04). Subjects with SQ pain scores <4/10 had lower leg and back pain scores than those with pain scores ≥4 at 1-month (mean 3.2, SD 2.6 vs 5.1, SD 2.7 for leg, P < 0.01; mean 3.7, SD 2.6 vs 5.0, SD 3.0 for back, P = 0.02) and 3-month (mean 3.8, SD 2.7 vs 5.2, SD 3.1 for leg, P = 0.01; mean 4.0, SD 2.6 vs 4.9, SD 3.1 for back; P = 0.14) follow-up. CONCLUSIONS: The results of this study found a weak positive correlation between SQ pain scores and treatment results. Further research should consider whether pain perception in conjunction with other variables might prove to be a reliable predictor for ESI and other procedural outcomes.

Establishing an optimal "cutoff" threshold for diagnostic lumbar facet blocks: a prospective correlational study.

OBJECTIVES: Diagnostic medial branch blocks (MBB) are considered the reference standard for diagnosing facetogenic pain and selecting patients for radiofrequency (RF) denervation. Great controversy exists regarding the ideal cutoff for designating a block as positive. The purpose of this study is to determine the optimal pain relief threshold for selecting patients for RF denervation after diagnostic MBB. METHODS: In this multicenter, prospective correlational study, 61 consecutive patients undergoing lumbar facet RF denervation after experiencing significant pain relief after MBB were enrolled. A positive outcome was defined as a ≥50% reduction in back pain at rest or with activity coupled with a positive satisfaction score lasting longer than 3 months. The relationship between pain relief after the blocks and denervation outcomes was evaluated by pairwise correlation matrix, receiver's operating characteristic curve, and stratifying outcomes based on 10- and 17-percentage point intervals for MBB. RESULTS: There were no significant differences in RF outcomes based on any MBB pain relief cutoff over 50%. A trend was noted whereby those patients who obtained <50% pain relief reported poorer outcomes. No optimal threshold for designating a diagnostic block as positive, above 50% pain relief, could be calculated. CONCLUSION: Employing more stringent selection criteria for lumbar facet RF is likely to result in withholding a beneficial procedure from a substantial number of patients, without improving success rates.

Epidural steroids, etanercept, or saline in subacute sciatica: a multicenter, randomized trial.

BACKGROUND: Perineural inhibitors of tumor necrosis factor have recently generated intense interest as an alternative to epidural steroid injections for lumbosacral radiculopathy. OBJECTIVE: To evaluate whether epidural steroids, etanercept, or saline better improves pain and function in adults with lumbosacral radiculopathy. DESIGN: A multicenter, 3-group, randomized, placebo-controlled trial conducted from 2008 to 2011. Randomization was computer-generated and stratified by site. Pharmacists prepared the syringes. Patients, treating physicians, and nurses assessing outcomes were blinded to treatment assignment. (ClinicalTrials.gov registration number: NCT00733096) SETTING: Military and civilian treatment centers. PATIENTS: 84 adults with lumbosacral radiculopathy of less than 6 months' duration. INTERVENTION: 2 epidural injections of steroids, etanercept, or saline, mixed with bupivacaine and separated by 2 weeks. MEASUREMENTS: The primary outcome measure was leg pain 1 month after the second injection. All patients had 1-month follow-up visits; patients whose condition improved remained blinded for the 6-month study period. RESULTS: The group that received epidural steroids had greater reductions in the primary outcome measure than those who received saline (mean difference, -1.26 [95% CI, -2.79 to 0.27]; P = 0.11) or etanercept (mean difference, -1.01 [CI, -2.60 to 0.58]; P = 0.21). For back pain, smaller differences favoring steroids compared with saline (mean difference, -0.52 [CI, -1.85 to 0.81]; P = 0.44) and etanercept (mean difference, -0.92 [CI,-2.28 to 0.44]; P = 0.18) were observed. The largest differences were noted for functional capacity, in which etanercept fared worse than the other treatments: steroids vs. etanercept (mean difference, -16.16 [CI, -26.05 to -6.27]; P = 0.002), steroids vs. saline (mean difference, -5.87 [CI, -15.59 to 3.85]; P = 0.23), and etanercept vs. saline (mean difference, 10.29 [CI, 0.55 to 20.04]; P = 0.04). More patients treated with epidural steroids (75%) reported 50% or greater leg pain relief and a positive global perceived effect at 1 month than those who received saline (50%) or etanercept (42%) (P = 0.09). LIMITATION: Short-term follow-up, small sample size, and a possibly subtherapeutic dose of etanercept. CONCLUSION: Epidural steroid injections may provide modest short-term pain relief for some adults with lumbosacral radiculopathy, but larger studies with longer follow-up are needed to confirm their benefits. PRIMARY FUNDING SOURCE: The John P. Murtha Neuroscience and Pain Institute, International Spinal Intervention Society, and Center for Rehabilitation Sciences Research.

Spine-area pain in military personnel: a review of epidemiology, etiology, diagnosis, and treatment.

BACKGROUND CONTEXT: Nonbattle illnesses and injuries are the major causes of unit attrition in modern warfare. Spine-area pain is a common disabling injury in service members associated with a very low return-to-duty (RTD) rate. PURPOSE: To provide an overview of the current understanding of epidemiology, possible causes, and relative prognosis of spine-area pain syndromes in military personnel, including a discussion of various treatment options available in theaters of operation. STUDY DESIGN: Literature review. METHODS: Search focusing on epidemiology, etiology and associative factors, and treatment of spinal pain using electronic databases, textbooks, bibliographic references, and personal accounts. RESULTS: Spine-area pain is the most common injury or complaint "in garrison" and appears to increase during training and combat deployments. Approximately three-quarters involve low back pain, followed by cervical and midback pain syndromes. Some predictive factors associated with spine-area pain are similar to those observed in civilian cohorts, such as psychosocial distress, heavy physical activity, and more sedentary lifestyle. Risk factors specific to military personnel include concomitant psychological trauma, g-force exposure in pilots and airmen, extreme shock and vibration exposure, heavy combat load requirements, and falls incurred during airborne, air assault, and urban dismounted ground operations. Effective forward-deployed treatment has been difficult to implement, but newer strategies may improve RTD rates. CONCLUSIONS: Spine-area pain syndromes comprise a major source of unit attrition and are often the result of duty-related burdens incurred during combat operations. Current strategies in theaters of operation that may improve the low RTD rates include individual and unit level psychological support, early resumption of at least some forward-area duties, multimodal treatments, and ergonomic modifications.

Effect of MRI on treatment results or decision making in patients with lumbosacral radiculopathy referred for epidural steroid injections: a multicenter, randomized controlled trial.

BACKGROUND: Studies have shown that radiologic imaging does not improve outcomes in most patients with back pain, though guidelines endorse it before epidural steroid injections (ESIs). The objective of this study was to determine whether magnetic resonance imaging (MRI) improves outcomes or affects decision making in patients with lumbosacral radiculopathy referred for ESI. METHODS: In this multicenter randomized study, the treating physician in group 1 patients was blinded to the MRI results, while the physician for group 2 patients decided on treatment after reviewing the MRI findings. In group 1 subjects, an independent physician proposed a treatment plan after reviewing the MRI, which was compared with the treatment the patient received. RESULTS: Slightly lower leg pain scores were noted in the group 2 at 1 month compared with MRI-blinded patients in group 1 (mean scores, 3.6 vs 4.4) (P = .12). No differences were observed in pain scores or function at 3 months. Overall, the proportion of patients who experienced a positive outcome was similar at all time points (35.4% at 3 months in group 1 vs 40.7% in group 2). Among subjects in group 1 who received a different injection than that proposed by the independent physician, scores for both leg pain (4.8 vs 2.4) (P = .01) and function (38.7 vs 28.2) (P = .04) were inferior to patients whose injection correlated with imaging. Collectively, 6.8% of patients did not (group 2) or would not have (group 1) received an ESI after the MRI was reviewed. CONCLUSION: Magnetic resonance imaging does not improve outcomes in patients who are clinical candidates for ESI and has only a minor effect on decision making. Trial Registration clinicaltrials.gov Identifier: NCT00826124.

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

BACKGROUND: Radiofrequency facet denervation is one of the most frequently performed procedures for chronic low back pain. Although sensory stimulation is generally used as a surrogate measure to denote sufficient proximity of the electrode to the nerve, no study has examined whether stimulation threshold influences outcome. METHODS: We prospectively recorded data in 61 consecutive patients undergoing lumbar facet radiofrequency denervation who experienced significant pain relief after medial branch blocks. For each nerve lesioned, multiple attempts were made to maximize sensory stimulation threshold (SST). Mean SST was calculated on the basis of the lowest stimulation perceived at 0.1-V increments for each medial branch. A positive outcome was defined as a ≥50% reduction in back pain coupled with a positive satisfaction score lasting ≥3 months. The relationship between mean SST and denervation outcomes was evaluated via a receiver's operating characteristic (ROC) curve, and stratifying outcomes on the basis of various cutoff values. RESULTS: No correlation was noted between mean SST and pain relief at rest (Pearson's r=-0.01, 95% confidence interval [CI]: -0.24 to 0.23, P=0.97), with activity (r=-0.17, 95% CI: -0.40 to 0.07, P=0.20), or a successful outcome. No optimal SST could be identified. CONCLUSIONS: There is no significant relationship between mean SST during lumbar facet radiofrequency denervation and treatment outcome, which may be due to differences in general sensory perception. Because stimulation threshold was optimized for each patient, these data cannot be interpreted to suggest that sensory testing should not be performed, or that high sensory stimulation thresholds obtained on the first attempt should be deemed acceptable.

Multicenter, randomized, comparative cost-effectiveness study comparing 0, 1, and 2 diagnostic medial branch (facet joint nerve) block treatment paradigms before lumbar facet radiofrequency denervation.

BACKGROUND: Among patients presenting with axial low back pain, facet arthropathy accounts for approximately 10-15% of cases. Facet interventions are the second most frequently performed procedures in pain clinics across the United States. Currently, there are no uniformly accepted criteria regarding how best to select patients for radiofrequency denervation. METHODS: A randomized, multicenter study was performed in 151 subjects with suspected lumbar facetogenic pain comparing three treatment paradigms. Group 0 received radiofrequency denervation based solely on clinical findings; group 1 underwent denervation contingent on a positive response to a single diagnostic block; and group 2 proceeded to denervation only if they obtained a positive response to comparative blocks done with lidocaine and bupivacaine. A positive outcome was predesignated as > or =50% pain relief coupled with a positive global perceived effect persisting for 3 months. RESULTS: In group 0, 17 patients (33%) obtained a successful outcome at 3 months versus eight patients (16%) in group 1 and 11 (22%) patients in group 2. Denervation success rates in groups 0, 1, and 2 were 33, 39, and 64%, respectively. Pain scores and functional capacity were significantly lower at 3 months but not at 1 month in group 2 subjects who proceeded to denervation compared with patients in groups 0 and 1. The costs per successful treatment in groups 0, 1, and 2 were $6,286, $17,142, and $15,241, respectively. CONCLUSIONS: Using current reimbursement scales, these findings suggest that proceeding to radiofrequency denervation without a diagnostic block is the most cost-effective treatment paradigm.