***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    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 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 The efficacy of fusion surgery in addition to decompression surgery in patients who have lumbar spinal stenosis , with or without degenerative spondylolisthesis , has not been substantiated in controlled trials . METHODS We r and omly assigned 247 patients between 50 and 80 years of age who had lumbar spinal stenosis at one or two adjacent vertebral levels to undergo either decompression surgery plus fusion surgery ( fusion group ) or decompression surgery alone ( decompression-alone group ) . R and omization was stratified according to the presence of preoperative degenerative spondylolisthesis ( in 135 patients ) or its absence . Outcomes were assessed with the use of patient-reported outcome measures , a 6-minute walk test , and a health economic evaluation . The primary outcome was the score on the Oswestry Disability Index ( ODI ; which ranges from 0 to 100 , with higher scores indicating more severe disability ) 2 years after surgery . The primary analysis , which was a per- protocol analysis , did not include the 14 patients who did not receive the assigned treatment and the 5 who were lost to follow-up . RESULTS There was no significant difference between the groups in the mean score on the ODI at 2 years ( 27 in the fusion group and 24 in the decompression-alone group , P=0.24 ) or in the results of the 6-minute walk test ( 397 m in the fusion group and 405 m in the decompression-alone group , P=0.72 ) . Results were similar between patients with and those without spondylolisthesis . Among the patients who had 5 years of follow-up and were eligible for inclusion in the 5-year analysis , there were no significant differences between the groups in clinical outcomes at 5 years . The mean length of hospitalization was 7.4 days in the fusion group and 4.1 days in the decompression-alone group ( P<0.001 ) . Operating time was longer , the amount of bleeding was greater , and surgical costs were higher in the fusion group than in the decompression-alone group . During a mean follow-up of 6.5 years , additional lumbar spine surgery was performed in 22 % of the patients in the fusion group and in 21 % of those in the decompression-alone group . CONCLUSIONS Among patients with lumbar spinal stenosis , with or without degenerative spondylolisthesis , decompression surgery plus fusion surgery did not result in better clinical outcomes at 2 years and 5 years than did decompression surgery alone . ( Funded by an Uppsala institutional Avtal om Läkarutbildning och Forskning [ Agreement concerning Cooperation on Medical Education and Research ] and others ; Swedish Spinal Stenosis Study Clinical Trials.gov number , NCT01994512 . ) We prospect ively evaluated the results of decompression of the spine , with and without arthrodesis , for the treatment of lumbar spinal stenosis without instability in forty-five patients ( twenty-one men and twenty-four women ) who had been managed between November 1989 and November 1990 . The average age at the time of the operation was sixty-seven years ( range , forty-eight to eighty-seven years ) . The patients were r and omly assigned to one of three treatment groups ( fifteen patients in each group ) according to when they were admitted to the hospital . Group I was treated with decompression with laminotomy and medial facetectomy ; Group II , with decompression and arthrodesis of the most stenotic segment ; and Group III , with decompression and arthrodesis of all of the decompressed vertebral segments . All of the operations were performed by the same surgeon . The average duration of follow-up was twenty-eight months ( range , twenty-four to thirty-two months ) . All three groups had a significant improvement in the distance that the patients were able to walk at the time of the latest follow-up examination compared with before the operation ( p < 0.001 for Group I , p < 0.002 for Group II , and p < 0.005 for Group III ) . With the numbers available , there were no significant differences in the results among the three groups with regard to the relief of pain ( p = 0.25 for Group I compared with Group II , p = 0.36 for Group II compared with Group III , and p = 0.92 for Group I compared with Group III ) . ( ABSTRACT TRUNCATED AT 250 WORDS 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 ] . ) Design . A prospect i ve , multicenter observational study . Objectives . 1 ) Identify correlates of the decision to perform arthrodesis in patients undergoing laminectomy for lumbar spinal stenosis . 2 ) Compare symptoms , walking capacity , and satisfaction 6 and 24 months after laminectomy alone and laminectomy with noninstrumented and with instrumented arthrodesis . Background Data . Few prospect i ve studies have compared outcomes of laminectomy alone or laminectomy with noninstrumented or with instrumented arthrodesis in patients with degenerative lumbar spinal stenosis . There is uncertainty regarding the optimal use of arthrodesis and instrumentation . Methods . Two hundred seventy‐two patients under‐going surgery for degenerative lumbar stenosis by eight surgeons at four centers were included in the study cohort . Of these , 37 had noninstrumented and 41 had instrumented arthrodesis .  Logistic regression identified factors associated with arthrodesis . The principal outcomes ‐health status , walking capacity , back and leg pain , and satisfaction with surgery‐were assessed 6 and 24 months postoperatively with univariate and multivariate techniques . Outcomes also were assessed in a restricted cohort of patients with at least 5 mm spondylolisthesis and /or 15 ° scoliosis .  Hospital costs were obtained from a computerized hospital cost accounting system . Results . The major predictor of the decision to perform arthrodesis was the individual surgeon ( P = 0.0001 ) . Noninstrumented arthrodesis was associated with superior relief of low back pain at 6 months ( P = 0.004 ) and 24 months ( P = 0.01 ) . This difference persisted in multivariate analyses , with borderline statistical significance . There were no significant differences in the other outcomes across treatment groups . Mean hospital costs  of laminectomy alone and noninstrumented and instrumented arthrodesis were $ 12,615 , $ 18,495 , and $ 25,914 , respectively ( P = 0.0001 ) . Conclusion . Findings were limited by the small number of participating surgeons , modest sample size that produced P values of borderline significance , and nonr and omized design . With these caveats in mind , the authors conclude : ( 1 ) The individual surgeon was a more important correlate of the decision to perform arthrodesis than clinical variables such as spondylolisthesis . ( 2 ) Noninstrumented arthrodesis result ed in superior relief of back pain after 6 and 24 months . ( 3 ) Instrumented arthrodesis was the most costly option . These results highlight the need for r and omized controlled trials and cost effectiveness analyses of lumbar arthrodesis and instrumentation in patients with degenerative lumbar spinal stenosis Background For young patients , the surgical method for lumbar disc herniation remains controversial . The aim of this study was to prospect ively determine the short‐term clinical outcome after surgery for young patients with lum 
    Output:
    
Mortality was not significantly associated with any treatment modality .
: Positive clinical change was greatest in patients undergoing fusion for spondylolisthesis while complications and the risk of reoperation limited the benefit of fusion for spinal stenosis .