***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: BACKGROUND Management of degenerative spondylolisthesis with spinal stenosis is controversial . Surgery is widely used , but its effectiveness in comparison with that of nonsurgical treatment has not been demonstrated in controlled trials . METHODS Surgical c and i date s from 13 centers in 11 U.S. states who had at least 12 weeks of symptoms and image-confirmed degenerative spondylolisthesis were offered enrollment in a  r and omized cohort or an  observational cohort . Treatment was st and ard decompressive laminectomy ( with or without fusion ) or usual nonsurgical care . The primary outcome measures were the Medical Outcomes Study 36-Item Short-Form General Health Survey ( SF-36 ) bodily pain and physical function scores ( 100-point scales , with higher scores indicating less severe symptoms ) and the modified Oswestry Disability Index ( 100-point scale , with lower scores indicating less severe symptoms ) at 6 weeks , 3 months , 6 months , 1 year , and 2 years . RESULTS We enrolled 304 patients in the r and omized cohort and 303 in the observational cohort . The baseline characteristics of the two cohorts were similar . The one-year crossover rates were high in the r and omized cohort ( approximately 40 % in each direction ) but moderate in the observational cohort ( 17 % crossover to surgery and 3 % crossover to nonsurgical care ) . The intention-to-treat analysis for the r and omized cohort showed no statistically significant effects for the primary outcomes . The as-treated analysis for both cohorts combined showed a significant advantage for surgery at 3 months that increased at 1 year and diminished only slightly at 2 years . The treatment effects at 2 years were 18.1 for bodily pain ( 95 % confidence interval [ CI ] , 14.5 to 21.7 ) , 18.3 for physical function ( 95 % CI , 14.6 to 21.9 ) , and -16.7 for the Oswestry Disability Index ( 95 % CI , -19.5 to -13.9 ) . There was little evidence of harm from either treatment . CONCLUSIONS In nonr and omized as-treated comparisons with careful control for potentially confounding baseline factors , patients with degenerative spondylolisthesis and spinal stenosis treated surgically showed substantially greater improvement in pain and function during a period of 2 years than patients treated nonsurgically . ( Clinical Trials.gov number , NCT00000409 [ Clinical Trials.gov ] . ) BACKGROUND Lumbar-disk surgery often is performed in patients who have sciatica that does not resolve within 6 weeks , but the optimal timing of surgery is not known . METHODS We r and omly assigned 283 patients who had had severe sciatica for 6 to 12 weeks to early surgery  or to prolonged conservative treatment with surgery if needed . The primary outcomes were the score on the Rol and Disability Question naire , the score on the visual-analogue scale for leg pain , and the patient 's report of perceived recovery during the first year after r and omization . Repeated- measures analysis according to the intention-to-treat principle was used to estimate the outcome curves for both groups . RESULTS Of 141 patients assigned to undergo early surgery  , 125 ( 89 % ) underwent  microdiskectomy  after a mean of 2.2 weeks . Of 142 patients design ated for conservative treatment , 55 ( 39 % ) were treated surgically after a mean of 18.7 weeks . There was no significant overall difference in disability scores during the first year ( P=0.13 ) . Relief of leg pain was faster for patients assigned to early surgery ( P<0.001 ) . Patients assigned to early surgery also reported a faster rate of perceived recovery ( hazard ratio , 1.97 ; 95 % confidence interval , 1.72 to 2.22 ; P<0.001 ) . In both groups , however , the probability of perceived recovery after 1 year of follow-up was 95 % . CONCLUSIONS The 1-year outcomes were similar for patients assigned to early surgery and those assigned to conservative treatment with eventual surgery if needed , but the rates of pain relief and of perceived recovery were faster for those assigned to early surgery . ( Current Controlled Trials number , IS RCT N26872154 [ controlled-trials.com ] . ) Summary of Background Data . The Spine Patient Outcomes Research Trial ( SPORT ) was design ed to assess the relative efficacy and cost-effectiveness of  surgical and nonsurgical approaches to the treatment of common conditions associated with low back and leg pain . Objectives . To describe the rationale and design of the SPORT project and to discuss its strengths and limitations . Study Design . Descriptive . Methods . First , the authors explain the rationale for embarking on SPORT , i.e. , deficiencies in the existing scientific knowledge base for treatment of these conditions . Second , the authors describe the design of SPORT , including topics such as specific aims , participating sites , study population , recruitment and enrollment , study interventions , follow-up , outcomes , statistical analysis , and study governance and organization . Finally , issues that complicate the performance of r and omized trials in surgery as they relate to the design and conduct of SPORT are discussed . Results . The SPORT project is being conducted at 11 clinical centers around the United States . It involves the simultaneous conduct of three multicenter , r and omized , controlled clinical trials . The study includes patients with the three most common diagnoses for which spine surgery is performed : intervertebral disc herniation , spinal stenosis , and degenerative spondylolisthesis , and it compares the most commonly used st and ard surgical and nonsurgical treatments for patients with these diagnoses . By the end of enrollment the authors anticipate a total of 500 patients with intervertebral disc herniation , 370 patients with spinal stenosis , and 300 patients with degenerative spondylolisthesis in the r and omized trials . Patients who meet the eligibility criteria but decline to be r and omized are invited to participate in an observational cohort study . Patients are being followed for a minimum of 24 months with visits scheduled at 6 weeks and at 3 , 6 , 12 , and 24 months . Conclusions . The results of this study will provide high- quality scientific evidence to aid clinical decision-making and improve treatment outcomes for these common , costly , and , in some instances , debilitating conditions Study Design . R and omized trial and concurrent observational cohort study . Objective . To compare 4 year outcomes of surgery to nonoperative care for spinal stenosis . Summary of Background Data . Surgery for spinal stenosis has been shown to be more effective compared to nonoperative treatment over 2 years , but longer-term data have not been analyzed . Methods . Surgical c and i date s from 13 centers in 11 US states with at least 12 weeks of symptoms and confirmatory imaging were enrolled in a r and omized cohort ( RC ) or observational cohort ( OC ) . Treatment was st and ard decompressive laminectomy or st and ard nonoperative care . Primary outcomes were SF-36 bodily pain ( BP ) and physical function scales and the modified Oswestry Disability index assessed at 6 weeks , 3 months , 6 months , and yearly up to 4 years . Results . A total of 289 patients enrolled in the RC and 365 patients enrolled in the OC . An as-treated analysis combining the RC and OC and adjusting for potential confounders found that the clinical ly significant advantages for surgery previously reported were maintained through 4 years , with treatment effects ( defined as mean change in surgery group minus mean change in nonoperative group ) for bodily pain 12.6 ( 95 % confidence interval [ CI ] , 8.5–16.7 ) ; physical function 8.6 ( 95 % CI , 4.6–12.6 ) ; and Oswestry Disability index −9.4 ( 95 % CI , −12.6 to −6.2 ) . Early advantages for surgical treatment for secondary measures such as bothersomeness , satisfaction with symptoms , and self-rated progress were also maintained . Conclusion . Patients with symptomatic spinal stenosis treated surgically compared to those treated nonoperatively maintain substantially greater improvement in pain and function through 4 years Objectives To evaluate the effects of early lumbar disc surgery compared with prolonged conservative care for patients with sciatica over two years of follow-up . Design R and omised controlled trial . Setting Nine Dutch hospitals . Participants 283 patients with 6 - 12 weeks of sciatica . Interventions Early surgery or an intended six months of continued conservative treatment , with delayed surgery if needed . Main outcome measures Scores from Rol and disability question naire for sciatica , visual analogue scale for leg pain , and Likert self rating scale of global perceived recovery . Results Of the 141 patients assigned to undergo early surgery  , 125 ( 89 % ) underwent  microdiscectomy . Of the 142 patients assigned to conservative treatment , 62 ( 44 % ) eventually required surgery , seven doing so in the second year of follow-up . There was no significant overall difference between treatment arms in disability scores during the first two years ( P=0.25 ) . Improvement in leg pain was faster for patients r and omised to early surgery , with a significant difference between “ areas under the curves ” over two years ( P=0.05 ) . This short term benefit of early surgery was no longer significant by six months and continued to narrow between six months and 24 months . Patient satisfaction decreased slightly between one and two years for both groups . At two years 20 % of all patients reported an unsatisfactory outcome . Conclusions Early surgery achieved more rapid relief of sciatica than conservative care , but outcomes were similar by one year and these did not change during the second year . Trial Registry IS RCT No 26872154 Objective This study describes the 5 years ’ results of the Sciatica trial focused on pain , disability , (un)satisfactory recovery and predictors for unsatisfactory recovery . Design A r and omised controlled trial . Setting Nine Dutch hospitals . Participants Five years ’ follow-up data from 231 of 283 patients ( 82 % ) were collected . Intervention Early surgery or an intended 6 months of conservative treatment . Main outcome measures Scores from Rol and disability question naire , visual analogue scale ( VAS ) for leg and back pain and a Likert self-rating scale of global perceived recovery were analysed . Results There were no significant differences between groups on the 5 years ’ primary outcome scores . Despite at least 6 months of conservative treatment 46 % of the conservatively allocated patients were treated surgically because of severe leg pain and disability . Forty-nine ( 21 % ) patients had an unsatisfactory recovery at 5 years and the recovery pattern showed that there was a variable group of 66 patients ( 31 % ) with at least one unsatisfactory outcome at 1 , 2 or 5 years of follow-up . Multivariate logistic regression showed that age ( > 40 ; OR 2.42 ( 95 % CI 1.16 to 5.02 ) ) , severity of leg pain ( VAS > 70 ; OR 3.32 ( 95 % CI 1.69 to 6.54 ) ) and the Mc Gill affective score ( score > 3 ; OR 6.23 ( 95 % CI 2.23 to 17.38 ) ) were the only significant predictors for an unsatisfactory outcome at 5 years . Conclusions In the long term , 8 % of the patients with sciatica never showed any recovery and in at least 23 % , sciatica appears to result in ongoing complaints , which fluctuate over time , irrespective of treatment . Prolonged conservative care might give patients a fair chance for pain and disability to resolve without surgery , but with the risk to receive delayed surgery after prolonged suffering of sciatica . Age above 40 years , severe leg pain at baseline and a higher affective Mc Gill pain score were predictors for unsatisfactory recovery . Trial Registry IS RCT No 26872154 BACKGROUND The management of degenerative spondylolisthesis associated with spinal stenosis remains controversial . Surgery is widely used and has recently been shown to be more effective than nonoperative treatment when the results were followed over two years . Questions remain regarding the long-term effects of surgical treatment compared with those of nonoperative treatment . METHODS Surgical c and i date s from thirteen centers with symptoms of at least twelve weeks ' duration as well as confirmatory imaging showing degenerative spondylolisthesis with spinal stenosis were offered enrollment in a r and omized cohort or observational cohort . Treatment consisted of st and ard decompressive laminectomy ( with or without fusion ) or usual nonoperative care . Primary outcome measures were the Short Form-36 ( SF-36 ) bodily pain and physical function scores and the modified Oswestry Disability Index at six weeks , three months , six months , and yearly up to four years . RESULTS In the r and omized cohort ( 304 patients enrolled ) , 66 % of those r and omized to receive surgery received it by four years whereas 54 % of those r and omized to receive nonoperative care received surgery by four years . In the observational cohort ( 303 patients enrolled ) , 97 % of those who chose surgery received it whereas 33 % of those who chose nonoperative care eventually received surgery . The intent-to-treat analysis of the r and omized cohort , which was limited by nonadherence to the assigned treatment , showed no significant differences in treatment outcomes between the operative and nonoperative groups at three or four years . An as-treated analysis combining the r and omized and observational cohorts that adjusted for potential confounders demonstrated that the clinical ly relevant advantages of surgery that had been previously reported through two years were maintained at four years , with treatment effects of 15.3 ( 95 % confidence 
    Output:
    
Long-term and greater than 2-year post-r and omisation results favoured surgery for spondylolisthesis and stenosis , although the size of the effects reduced with time .
For disc herniation , no significant effect was shown for leg and back pain comparing surgery to physical activity .
For spondylolisthesis and spinal stenosis , surgery is superior to physical activity up to greater than 2 years follow-up .