***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: Study Design . Single blind r and omized study . Objectives . To compare the effectiveness of  lumbar instrumented fusion with cognitive intervention and exercises in patients with chronic low back pain and disc degeneration . Summary of Background Data . To the authors ’ best knowledge , only one r and omized study has evaluated the effectiveness of lumbar fusion . The Swedish Lumbar Spine Study reported that lumbar fusion was better than continuing physiotherapy and care by the family physician . Patients and Methods . Sixty-four patients aged 25–60 years with low back pain lasting longer than 1 year and evidence of disc degeneration at L4–L5 and /or L5–S1 at radiographic examination were r and omized to either lumbar fusion with posterior transpedicular screws and postoperative physiotherapy , or cognitive intervention and exercises . The cognitive intervention consisted of a lecture to give the patient an underst and ing that ordinary physical activity would not harm the disc and a recommendation to use the back and bend it . This was reinforced by three daily physical exercise sessions for 3 weeks . The main outcome measure was the Oswestry Disability Index . Results . At the 1-year follow-up visit , 97 % of the patients , including 6 patients who had either not attended treatment or changed groups , were examined . The Oswestry Disability Index was significantly reduced from 41 to 26 after surgery , compared with 42 to 30 after cognitive intervention and exercises . The mean difference between groups was 2.3 ( −6.7 to 11.4 ) ( P = 0.33 ) . Improvements inback pain , use of analgesics , emotional distress , life satisfaction , and return to work were not different . Fear-avoidance beliefs and fingertip-floor distance were reduced more after nonoperative treatment , and lower limb pain was reduced more after surgery . The success rateaccording to an independent observer was 70 % after surgery and 76 % after cognitive intervention and exercises .  The early complication rate in the surgical group was 18 % . Conclusion . The main outcome measure showed equal improvement in patients with chronic low back pain and disc degeneration r and omized to cognitive intervention and exercises , or lumbar fusion Study Design . A prospect i ve , r and omized , multicenter , Food and Drug Administration-regulated Investigational Device Exemption clinical trial . Objective . To evaluate the safety and effectiveness of the ProDisc ® -L ( Synthes Spine , West Chester , PA ) lumbar total disc replacement compared to circumferential spinal fusion for the treatment of discogenic pain at 1 vertebral level between L3 and S1 . Summary of Background Data . As part of the Investigational Device Exemption clinical trial , favorable single center results of lumbar total disc replacement with the ProDisc ® -L have been reported previously . Methods . Two hundred eighty-six ( 286 ) patients were treated on protocol . Patients were evaluated before and after surgery , at 6 weeks , 3 , 6 , 12 , 18 , and 24 months . Evaluation at each visit included patient self- assessment s , physical and neurologic examinations , and radiographic evaluation . Results . Safety of ProDisc ® -L implantation was demonstrated with 0 % major complications . At 24 months , 91.8 % of investigational and 84.5 % of control patients reported improvement in the Oswestry Low Back Pain Disability Question naire ( Oswestry Disability Index [ ODI ] ) from preoperative levels , and 77.2 % of investigational and 64.8 % of control patients met the ≥15 % Oswestry Disability Index improvement criteria . Overall neurologic success in the investigational group was superior to the control group ( 91.2 % investigational and 81.4 % control ; P = 0.0341 ) . At 6 weeks and 3 months follow-up time points , the ProDisc ® -L patients recorded SF-36 Health Survey scores significantly higher than the control group ( P = 0.018 , P = 0.0036 , respectively ) . The visual analog scale pain assessment showed statistically significant improvement from preoperative levels regardless of treatment ( P < 0.0001 ) . Visual analog scale patient satisfaction at 24 months showed a statistically significant difference favoring investigational patients over the control group ( P = 0.015 ) . Radiographic range of motion was maintained within a normal functional range in 93.7 % of investigational patients and averaged 7.7 ° . Conclusions . ProDisc ® -L has been found to be safe and efficacious . In properly chosen patients , ProDisc ® -L has been shown to be superior to circumferential fusion by multiple clinical criteria Mixed treatment comparison ( MTC ) meta- analysis is a generalization of st and ard pairwise meta- analysis for A vs B trials , to data structures that include , for example , A vs B , B vs C , and A vs C trials . There are two roles for MTC : one is to strengthen inference concerning the relative efficacy of two treatments , by including both ' direct ' and ' indirect ' comparisons . The other is to facilitate simultaneous inference regarding all treatments , in order for example to select the best treatment . In this paper , we present a range of Bayesian hierarchical models using the Markov chain Monte Carlo software WinBUGS . These are multivariate r and om effects models that allow for variation in true treatment effects across trials . We consider models where the between-trials variance is homogeneous across treatment comparisons as well as heterogeneous variance models . We also compare models with fixed ( unconstrained ) baseline study effects with models with r and om baselines drawn from a common distribution . These models are applied to an illustrative data set and posterior parameter distributions are compared . We discuss model critique and model selection , illustrating the role of Bayesian deviance analysis , and node-based model criticism . The assumptions underlying the MTC models and their parameterization are also discussed Abstract Objectives To assess the clinical effectiveness of surgical stabilisation ( spinal fusion ) compared with intensive rehabilitation for patients with chronic low back pain . Design Multicentre r and omised controlled trial . Setting 15 secondary care orthopaedic and rehabilitation centres across the United Kingdom . Participants 349 participants aged 18 - 55 with chronic low back pain of at least one year 's duration who were considered c and i date s for spinal fusion . Intervention Lumbar spine fusion or an intensive rehabilitation programme based on principles of cognitive behaviour therapy . Main outcome measure The primary outcomes were the Oswestry disability index and the shuttle walking test measured at baseline and two years after r and omisation . The SF-36 instrument was used as a secondary outcome measure . Results 176 participants were assigned to surgery and 173 to rehabilitation . 284 ( 81 % ) provided follow-up data at 24 months . The mean Oswestry disability index changed favourably from 46.5 ( SD 14.6 ) to 34.0 ( SD 21.1 ) in the surgery group and from 44.8 ( SD14.8 ) to 36.1 ( SD 20.6 ) in the rehabilitation group . The estimated mean difference between the groups was –4.1 ( 95 % confidence interval –8.1 to –0.1 , P = 0.045 ) in favour of surgery . No significant differences between the treatment groups were observed in the shuttle walking test or any of the other outcome measures . Conclusions Both groups reported reductions in disability during two years of follow-up , possibly unrelated to the interventions . The statistical difference between treatment groups in one of the two primary outcome measures was marginal and only just reached the predefined minimal clinical difference , and the potential risk and additional cost of surgery also need to be considered . No clear evidence emerged that primary spinal fusion surgery was any more beneficial than intensive rehabilitation Study Design . R and omized , controlled , multicenter , investigational device exemption trial . Objective . To investigate the safety and effectiveness of the first two-piece , metal-on-metal lumbar disc prosthesis for treating patients with single-level degenerative disc disease . Summary of Background Data . For patients with degenerative disc disease unresponsive to conservative measures , lumbar disc arthroplasty provides an alternative to fusion design ed to relieve persistent discogenic pain and maintain motion . Methods . After 2:1 r and omization , 577 patients were treated in either the investigational group ( 405 ) , receiving lumbar disc arthroplasty , or the control group ( 172 ) , receiving anterior lumbar interbody fusion .  Patients were evaluated preoperatively , at surgery/discharge , and at 1.5 , 3 , 6 , 12 , and 24 months after surgery . The primary study endpoint was overall success , a composite measure of safety and effectiveness as recommended by the Food and Drug Administration and defined in the protocol . Results . Both treatment groups demonstrated significant improvements compared with preoperative status . The investigational group had statistically superior outcomes ( P < 0.05 ) at all postoperative evaluations in Oswestry Disability Index , back pain , and Short Form-36 Physical Component Summary scores as well as patient satisfaction . Investigational patients had longer surgical times ( P < 0.001 ) and greater blood loss ( P < 0.001 ) than did control patients ; however , hospitalization stays were similar for both groups . Investigational patients had fewer implant or implant/surgical procedure-related adverse events ( P < 0.001 ) . Return-to-work intervals were reduced for investigational patients . Disc height and segmental angular motion were maintained throughout the study in the investigational group . In the investigational group , overall success superiority was found when compared to the control group as defined by the Food and Drug Administration Investigational Device Exemption protocol . Conclusion . The investigational group consistently demonstrated statistical superiority versus fusion on key clinical outcomes including improved physical function , reduced pain , and earlier return to work Purpose To compare the 9-year outcome in patients with chronic low back pain treated by  instrumented lumbar fusion  versus cognitive intervention and exercises . Methods The main outcome measure was the Oswestry Disability Index ( ODI ) . Secondary outcome measures included pain , fear-avoidance beliefs , trunk muscle strength , medication , and return to work . Results One-third of the patients r and omized to cognitive intervention and exercises  had crossed over and been operated and one-third of the patients allocated to lumbar fusion had been re-operated . The intention-to-treat analysis detected no differences between the two groups . The mean adjusted treatment effect for ODI was 1.9 ( 95 % CI −7.8 to 11.6 ) . Analysed according to the treatment received , more operated patients used pain medication and were out of work . Conclusions The outcome at 9 years was not different between instrumented lumbar fusion and cognitive intervention and exercises The study design includes a prospect i ve , r and omised controlled study comparing total disc replacement ( TDR ) with posterior fusion . The main objective of this study is to compare TDR with lumbar spinal fusion , in terms of clinical outcome , in patients referred to a spine clinic for surgical evaluation .  Fusion is effective for treating chronic low back pain ( LBP ) , but has drawbacks , such as stiffness and possibly adjacent level degradation . Motion-preserving options have emerged , of which TDR is frequently used because of these drawbacks . How the results of TDR compare to fusion , however , is uncertain . One hundred and fifty-two patients with a mean age of 40 years ( 21–55 ) were included : 90 were women , and 80 underwent TDR . The patients had not responded to a conservative treatment programme and suffered from predominantly LBP , with varying degrees of leg pain . Diagnosis was based on clinical examination , radiographs , MRI , and in unclear cases , diagnostic injections . Outcome measures were global assessment ( GA ) , VAS for back and leg pain , Oswestry Disability Index , SF36 and EQ5D at 1 and 2 years . Follow-up rate was 100 % , at both 1 and 2 years . All outcome variables improved in both groups between preoperative and follow-up assessment . The primary outcome measure , GA , revealed that 30 % in the TDR group and 15 % in the fusion group were totally pain-free at 2 years ( P = 0.031 ) . TDR patients had reached maximum recovery in virtually all variables at 1 year , with significant differences compared to the fusion group . The fusion patients continued to improve and at 2 years had results similar to TDR patients apart from numbers of pain-free . Complications and reoperations were similar in both groups , but pedicle screw removal as additive surgery , was frequent in the fusion group . One year after surgery , TDR was superior to spinal fusion in clinical outcome , but this difference had diminished by 2 years , apart from ( VAS for back pain and ) numbers of pain-free . The long-term benefits have yet to be examined BACKGROUND Disc replacement arthroplasty previously has been shown to be an effective alternative to spine fusion for the treatment of single-level lumbar degenerative disc disease . The purpose of the present study was to determine the twenty-four-month results of a clinical trial of the ProDisc-L total disc replacement as compared with spinal fusion for the treatment of degenerative disc disease at two contiguous vertebral levels from L3 to S1 . METHODS A total of 237 patients were treated in a r and omized controlled trial design ed as a non-inferiority study for regulatory application purpose s. Blocked r and omization was performed with use of a 2:1 ratio of total disc arthroplasty to circumferential arthrodesis . Evaluations , including patient self- assessment s , physical and neurological examinations , and radiographic examinations , were performed preoperatively , six weeks postoperatively , and three , six , twelve , eighteen , and twenty-four months postoperatively . RESULTS At twenty-four months , 58.8 % ( eighty-seven ) of 148 patients in the total disc replacement group were classified as a statistical success , compared with 47.8 % ( thirty-two ) of sixty-seven patients in the arthrodesis group ; non-inferiority was demonstrated . The mean Oswestry Disability Index in both groups significantly improved from baseline ( p < 0.00 
    Output:
    
Conclusions : All 4 treatments provided some benefit to patients with chronic LBP .
According to the MTC analysis , TDR may be the most effective treatment and PT the least effective treatment for chronic LBP .
This review is based on a limited number of RCT studies and does not support any 1 treatment modality for all patients