***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: One hundred seventy-six consecutive patients with chronic low-back pain and no history of previous lumbar surgery were studied to test the clinical criteria of Fairbank et al. and Helbig and Lee for zygapophysial joint pain . All patients underwent a history , examination , and a series of zygapophysial joint injections or blocks of the medial branches of the dorsal ramus with lignocaine . Those patients responding to the first series of blocks were given confirmatory blocks using bupivacaine . None of the clinical features tested was found to be associated with response to the confirmatory block . The Fairbank et al. and Helbig and Lee criteria were shown to be unreliable in distinguishing pain of zygapophysial joint origin from pain of other origins Background Back pain is common and some sufferers consult GPs , yet many sufferers develop persistent problems . Combining information on risk of persistence and prognostic indicator prevalence provides more information on potential intervention targets than risk estimates alone . Aims To determine the proportion of primary care back pain patients with persistent problems whose outcome is related to measurable prognostic factors . Methods Prospect i ve cohort study of back pain patients ( 30–59 years ) at five general practice s in Staffordshire , UK ( n = 389 ) . Baseline factors ( demographic ; episode duration ; symptom severity ; pain widespreadness ; anxiety ; depression ; catastrophising ; fear-avoidance ; self-rated health ) were assessed for their association with disabling and limiting pain after 12-months . The proportion of those with persistent problems whose outcome was related to each factor was calculated . Results Prevalence of prognostic factors ranged from 23 % to 87 % . Strongest predictors were unemployment ( adjusted relative risk ( RR ) 4.2 ; 95 % CI 2.0 , 8.5 ) and high pain intensity ( 4.1 ; 1.7 , 9.9 ) . The largest proportions of persistent problems were related to high pain intensity ( 68 % ; 95 % CI 27 , 87 % ) and unemployment ( 64 % ; 33 , 82 % ) . Combining these indicated that 85 % of poor back pain outcome is related to these two factors . Poor self-rated health , functional disability , upper body pain and pain bothersomeness were related with outcome for over 40 % of those with persistent problems . Conclusions Several factors increased risk of poor outcome in back pain patients , notably high pain and unemployment . These risks in combination with high prevalence of risk factors in this population distinguish factors that can help identify targets or sub-groups for intervention STUDY DESIGN A prospect i ve double-blind r and omized trial in 31 patients . OBJECTIVES To assess the clinical efficacy of percutaneous radiofrequency denervation of the lumbar zygapophysial joints in reducing pain , functional disability , and physical impairment in patients with back pain originating from the lumbar zygapophysial joints . SUMMARY OF BACKGROUND DATA Chronic low back pain is a major health problem in the industrialized world . A treatment option is percutaneous radiofrequency denervation of the lumbar zygapophysial joints . Its clinical efficacy has never been formally tested in a controlled trial . METHODS Thirty-one patients with a history of at least 1 year of chronic low back pain were selected on the basis of a positive response to a diagnostic nerve blockade and subsequently r and omly assigned to one of two treatment groups . Each patient in the radiofrequency treatment group ( 15 patients ) received an 80 C radiofrequency lesion of the dorsal ramus of the segmental nerve roots L3 , L4 , and L5 . Patients in the  control group ( n = 16 ) underwent an the same procedure but without use of a radiofrequency current . Both the treating physician and the patients were blinded to the group assignment . Before treatment , physical impairment , rating of pain , the degree of disability , and quality of life were assessed by a blinded investigator . RESULTS Eight weeks after treatment , there were 10 success patients in the radiofrequency group ( n = 15 ) and 6 in the sham group ( n = 16 ) . The unadjusted odds ratio was 3.3 ( P = 0.05 , not significant ) , and the adjusted odds ratio was 4.8 ( P < 0.05 , significant ) . The differences in effect on the visual analog scale scores , global perceived effect , and the Oswestry disability scale were statistically significant . Three , 6 , and 12 months after treatment , there were significantly more success patients in the radiofrequency group compared with the sham group . CONCLUSIONS Radiofrequency lumbar zygapophysial joint denervation results in a significant alleviation of pain and functional disability in a select group of patients with chronic low back pain , both on a short-term and a long-term basis Objectives : Radiofrequency facet joint denervation procedures have been common practice for 2 decades in treatment of chronic low back pain . We design ed this multicenter , r and omized , double-blind , sham treatment controlled trial to determine the efficacy of radiofrequency facet joint denervation , as it is routinely performed . Methods : Inclusion criteria were low back pain , duration more than 6 months , and ≥50 % Visual Analog Scale ( VAS ) reduction on diagnostic block . Exclusion criteria were prior radiofrequency treatment , radicular syndrome , coagulopathies , specific allergies , cancer , and pregnancy . A total of 81 out of 462 patients were r and omized to undergo radiofrequency facet joint denervation or sham treatment . The first evaluation was carried out 3 months after treatment . Primary outcome was determined with a combined outcome measure comprising VAS , physical activities , and analgesic intake , from a twice-weekly recorded diary . Secondary outcome measures were the separate diary parameters , global perceived effect ( complete relief , > 50 % relief , no effect , pain increase ) , and SF-36 Quality of Life Question naire . Results : There were no dropouts before the first evaluation . The combined outcome measure showed no differences between radio- frequency facet joint denervation ( n = 40 ; success 27.5 % ) and sham ( n = 41 ; success 29.3 % ) ( P = 0.86 ) . The VAS in both groups improved ( P < 0.001 ) . Global perceived effect improved after radiofrequency facet joint denervation ( P < 0.05 ) . The other secondary outcome parameters showed no significant differences . Relevant costs were evaluated . Discussion : The combined outcome measure and VAS showed no difference between radiofrequency and sham , though in both groups , significant VAS improvement occurred . The global perceived effect was in favor of radiofrequency . In selected patients , radiofrequency facet joint denervation appears to be more effective than sham treatment BACKGROUND : Lumbar facet joint degeneration is a source of chronic low back pain , with an incidence of 15 % to 45 % among patients with low back pain . Various therapeutic techniques in the treatment of facet-related pain have been described in the literature , including intraarticular lumbar facet joint steroid injections and radiofrequency denervation . In this study , we compared the effectiveness of intraarticular facet joint steroid injections and radiofrequency denervation . METHODS : Our r and omized , double-blind , controlled study included patients who received intraarticular steroid infiltrations in the lumbar facet joints ( L3/L4–L5/S1 ) and patients who underwent radiofrequency denervation of L3/L4–L5/S1 segments . The inclusion criteria were based first on magnetic resonance imaging findings showing hypertrophy of the facet joints L3/L4–L5/S1 and a positive response to an intraarticular test infiltration of the facet joints L3/L4–L5/S1 with local anesthetics . The primary end point was the Rol and -Morris Question naire . Secondary end points were the visual analog scale and the Oswestry Disability Index . All outcome assessment s were performed at baseline and at 6 months . RESULTS : Fifty-six patients were r and omized ; 24 of 29 patients in the steroid injection  group and 26 of 27 patients in the denervation  group completed the 6-month follow-up . Pain relief and functional improvement were observed in both groups . There were no significant differences between the 2 groups for the primary end point ( 95 % confidence interval [ CI ] , −3 to 4 ) and for both secondary end points ( 95 % CI for visual analog scale , −2 to 1 ; 95 % CI for Oswestry Disability Index , −18 to 0 ) . CONCLUSIONS : Intraarticular steroid infiltration or radiofrequency denervation appear to be a managing option for chronic function-limiting low back pain of facet origin with favorable short- and midterm results in terms of pain relief and function improvement , but improvements were similar in both groups 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 r and omized , 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 pre design ated as ≥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 Study Design . A prospect i ve double-blind r and omized controlled trial was performed . Objective . To assess the efficacy of percutaneous radiofrequency articular facet denervation for  low back pain .  Summary of Background Data . Uncontrolled observational studies in patients with low back pain have reported some benefits from the use of facet joint radiofrequency denervation . Because the efficacy of percutaneous radiofrequency had not been clearly shown in previous studies , a r and omized controlled trial was conducted to assess the efficacy of the technique for improving functional disabilities and reduce pain . Methods . For this study , 70 patients with low back pain lasting of more than 3 months duration and a good response after intraarticular facet injections under fluoroscopy were assigned r and omly to receive percutaneous radiofrequency articular facet denervation under fluoroscopic guidance or the same procedure without effective denervation ( sham therapy ) . The primary outcomes were functional disabilities , as assessed by the Oswestry and Rol and -Morris scales , and pain indicated on a visual analog scale . Secondary outcomes included spinal mobility and strength . Results . At 4 weeks , the Rol and -Morris score had improved by a mean of 8.4 % in the neurotomy group and 2.2 % in the placebo group , showing a treatment effect of 6.2 % ( P = 0.05 ) . At 4 weeks , no significant treatment effect was reflected in the Oswestry score ( 0.6 % change ) or the visual analog pain score ( 4.2 % change ) . At 12 weeks , neither functional disability , as assessed by the Rol and -Morris scale ( 2.6 % change ) and Oswestry scale ( 1.9 % change ) , nor the pain level , as assessed by the visual analog scale ( −7.6 % change ) , showed any treatment effect . Conclusions . Although radiofrequency facet joint denervation may provide some short-term improvement in functional disability among patients with chronic low back pain , the efficacy of this treatment has not been established Background and objectives Radiofrequency facet denervation procedures are widely used for the treatment of  chronic low-back pain .  Currently , both temperature-controlled and voltage-controlled techniques are used . In this combined in vivo and in vitro study , the electrophysiologic consequences and the effects on lesion size of these techniques were determined . Methods Thirty-three patients were r and omly assigned to receive a lumbar radiofrequency facet denervation by using either temperature-controlled ( 80 ° C , 60 seconds ) or voltage-controlled ( 20 V , 60 s ) mode . Electrophysiologic parameters in both groups during radiofrequency lesioning were registered . Observed differences between electrodes were quantified and interpreted , using lesion-size data from egg-white experiments . Results Seventeen patients in the temperature group were treated with a total of 55 radiofrequency lesions , all considered technically adequate . In the voltage-controlled group , 16 patients received 63 lesions . Of these , 44 ( 69.8 % ) procedures were found to be technically inadequate . Voltage-controlled radiofrequency lesioning result ed in uncontrollable fluctuations of temperature , with result ant uncontrollable variations in lesion size . Temperature-controlled mode created reproducible lesion sizes . Conclusions There is no consistent relation between voltage and the temperature obtained during radiofrequency lumbar facet denervation . 
    Output:
    
The evidence favored FJRD regarding pain control .
There was no sufficient evidence for cost-effectiveness and complications .
The data indicate that FJRD is more effective than placebo in pain control and functional improvement and is also possibly more effective than steroid injections in pain control .
Complications and adverse effects were not sufficiently reported to allow comparisons , and there was no evidence for cost-effectiveness .