***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 CONTEXT There is mounting evidence supporting the efficacy of bone morphogenetic protein ( BMP ) for both anterior interbody and posterolateral lumbar fusion . However , the relative cost of BMP remains an important concern for physicians , hospitals , and payers . PURPOSE The purpose of this study is to report on the perioperative costs for patients treated with rhBMP-2 as compared with an iliac crest bone graft ( ICBG ) supplemented with graft extenders .  STUDY DESIGN / SETTING A prospect i ve r and omized controlled trial of rhBMP-2/ACS ( Infuse Bone Graft ; Medtronic Sofamor Danek , Memphis , TN ) versus ICBG+/-graft extender for lumbar spine fusion in patients over 60 years old . PATIENT SAMPLE One hundred two patients over 60 years old who required a posterolateral lumbar spine fusion r and omized between receiving rhBMP-2/ACS or ICBG .  OUTCOME MEASURES All health-care costs over the first 3 months after surgery . METHODS As part of a prospect i ve r and omized trial of rhBMP-2/ACS versus ICBG+/-graft extender for lumbar spine fusion , all costs over the first 3 months after surgery were directly recorded by a dedicated coder funded by Norton Healthcare , Louisville , KY . A dedicated research nurse also followed all patients throughout their hospital stay and posthospitalization recovery to identify any adverse events or additional outpatient medical care . RESULTS Fifty patients received rhBMP-2/ACS and 52 underwent ICBG harvest . The mean hospital cost for the index admission was $ 24,736 for the rhBMP-2/ACS group and $ 21,138 for the ICBG group . Mean inpatient physician costs were $ 5,082 in the rhBMP-2/ACS group and $ 5,316 in the ICBG group . Costs associated with posthospital rehabilitation averaged $ 4,906 in the rhBMP-2/ACS group versus $ 6,820 in the ICBG group . Total payer expenditure for the 3-month perioperative period averaged $ 33,860 in the rhBMP-2/ACS group and $ 37,227 in the ICBG group . CONCLUSIONS The hospital carries the cost burden associated with the utilization of rhBMP-2/ACS . In contrast , the payer in a Diagnosis-Related Group ( DRG ) model achieves a net savings , based primarily on the decreased payment for inpatient rehabilitation , but also on decreased hospital reimbursement , physician costs , and other outpatient services PURPOSE We sought to determine whether percutaneous vertebroplasty -- which involves the injection of cement to stabilize a fractured vertebral body -- may be an effective treatment for vertebral fracture . METHODS We enrolled 79 consecutive osteoporotic patients ( 24 men and 55 women ; ages 51 to 93 years ) presenting with acute vertebral fractures . Clinical characteristics and bone densitometry were measured at baseline . Pain scores ( on a 0 to 25 scale ) and levels of function ( on a 0 to 20 scale ) were recorded on presentation , at 24 hours , at 6 weeks , and 6 to 12 months after therapy . RESULTS Fifty-five patients ( 70 % ) were treated by percutaneous vertebroplasty and 24 ( 30 % ) were treated by conservative therapy alone . They were followed for a mean of 215 days ( range , 57 to 399 days ) . The baseline clinical characteristics , bone densitometry , and fracture data were similar in the two groups . Twenty-four hours after vertebroplasty , there was a 53 % reduction in pain scores ( from 19 to 9 ; P = 0.0001 ) and a 29 % improvement in physical functioning ( from 14 to 18 ; P = 0.0001 ) , whereas pain scores and physical functioning remained unchanged at 24 hours in the patients treated conservatively ( both P = 0.0001 compared with the changes after percutaneous vertebroplasty ) . Thirteen patients ( 24 % ) treated by percutaneous vertebroplasty were able to cease all analgesia after 24 hours ( P = 0.0001 compared with none of the 24 patients treated conservatively ) . Clinical outcomes at 6 weeks and 6 to 12 months were similar in both groups . CONCLUSION When compared with conservative therapy , percutaneous vertebroplasty results in prompt pain relief and rapid rehabilitation . In experienced h and s , it is a safe and effective procedure for treating acute osteoporotic vertebral compression fractures BACKGROUND The impact of fusion as a supplement to short-segment instrumentation for the treatment of thoracolumbar burst fractures is unclear . We conducted a controlled clinical trial to define the effect of fusion on lumbar spine and patient-related functional outcomes . METHODS From 2000 to 2002 , seventy-three consecutive patients with a single-level Denis type-B burst fracture involving the thoracolumbar spine and a load-sharing score of < or=6 were managed with posterior pedicle screw instrumentation .  The patients were r and omly assigned to treatment with posterolateral fusion ( fusion group , n = 37 ) or without posterolateral fusion ( nonfusion group , n = 36 ) . The patients were followed for at least five years after surgery and were assessed with regard to clinical and radiographic outcomes . Clinical outcomes were evaluated with use of the Frankel scale , the motor score of the American Spinal Injury Association , a visual analog scale , and the Short Form-36 ( SF-36 ) question naire . Radiographic outcomes were assessed on the basis of the local kyphosis angle and loss of kyphosis correction . RESULTS No significant difference in radiographic or clinical outcomes was noted between the patients managed with the two techniques . Both operative time and blood loss were significantly less in the nonfusion group compared with the fusion group ( p < 0.05 ) . Twenty-five of the thirty-seven patients in the fusion group still had some degree of donor-site pain at the time of the latest examination . CONCLUSIONS Posterolateral bone-grafting is not necessary when a Denis type-B thoracolumbar burst fracture associated with a load-sharing score of < or=6 is treated with short-segment pedicle screw fixation 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 interval , 11 to 19.7 ) for bodily pain , 18.9 ( 95 % confidence interval , 14.8 to 23 ) for physical function , and -14.3 ( 95 % confidence interval , -17.5 to -11.1 ) for the Oswestry Disability Index . Early advantages ( at two years ) of surgical treatment in terms of the secondary measures of bothersomeness of back and leg symptoms , overall satisfaction with current symptoms , and self-rated progress were also maintained at four years . CONCLUSIONS Compared with patients who are treated nonoperatively , patients in whom degenerative spondylolisthesis and associated spinal stenosis are treated surgically maintain substantially greater pain relief and improvement in function for four years OBJECTIVE To assess the safety and efficacy of percutaneous vertebroplasty for the treatment of acute osteoporotic vertebral fractures . DESIGN A prospect i ve , non-r and omised , " intention-to-treat " 2-year study . PATIENTS AND SETTING 126 consecutive patients ( 39 men and 87 women , aged 51 - 95 years ) with acute osteoporotic vertebral fractures presenting to St George Hospital from November 2000 to December 2002 . They comprised 88 patients treated by percutaneous vertebroplasty  and 38 by conservative therapy . MAIN OUTCOME MEASURES Primary outcomes --changes in patients ' pain score and level of function recorded at 24 hours , 6 weeks , 6 - 12 months and 24 months after therapy . Secondary outcomes --occurrence of new clinical or radiological vertebral fractures and survival at 2 years . RESULTS Three minor complications ( fractured pedicle and psoas muscle haemorrhage ) occurred in the vertebroplasty group during the first year of the study . Outcomes in vertebroplasty-treated patients ( 60 % reduction in visual analogue pain scores from 20 to 8 ; P < 0.001 ) , a rapid return to normal function ( 29 % improvement in physical functioning from 14 to 18 ; P < 0.001 ) and lower rates of hospitalisation ( 43 % reduction in the mean number of hospital bed-days occupied ) were better than those treated conservatively ( P < 0.001 for the comparison of all variables at 24 hours ) . Lower pain scores persisted in the vertebroplasty-treated group at 6 weeks ( P < 0.001 ) , but no differences between the two groups were evident at 12 and 24 months . In the vertebroplasty-treated group compared with the control group , the rates of new vertebral fractures ( clinical ly and by radiographic assessment ) ( hazard ratio , 1.13 ; 95 % CI , 0.52 - 2.46 ; P = 0.76 ) and death ( hazard ratio , 1.07 ; 95 % CI , 0. 
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Nonetheless the clinical question remains : is immediate routine  lumbar spine imaging more effective than usual care without imaging in patients with low back pain and no suggestion of “ red flags . ”