***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 
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    ***EXAMPLES*** 
    Input: Study Design . Prospect i ve , multicenter , r and omized , controlled , investigational device exemption noninferiority trial . Objective . To determine 2-year outcomes in patients with intermittent neurogenic claudication secondary to moderate lumbar spinal stenosis ( LSS ) who were treated with the Superion interspinous process spacer .  Summary of Background Data . Interspinous spacers are a less-invasive treatment alternative compared with surgical decompression for patients with LSS unresponsive to conservative care . High- quality comparative data with these devices are lacking . Methods . Patients presenting with intermittent neurogenic claudication secondary to moderate LSS who failed at least 6 months of nonsurgical management were r and omly allocated to treatment with the Superion spacer or a control spacer ( X-Stop ) and followed for 2 years . Results . A total of 391 r and omized patients were implanted with  Superion ( n = 190 ) or control ( n = 201 ) spacers  at 29 sites in the United States between August 2008 and December 2011 . Implants were successfully implanted in 99.5 % of patients with Superion and 99.0 % of control patients . The primary composite endpoint of this study was met , which demonstrated that the Superion spacer was noninferior to the X-Stop spacer . Leg pain , the predominant patient complaint , decreased in severity by 70 % during 2 years in each group . Most ( 77 % ) patients achieved leg pain clinical success ( improvement ≥20 mm ) at 2 years . Back pain clinical success ( improvement ≥20 mm ) was 68 % , with no differences between groups . Oswestry Disability Index clinical success ( ≥15 % point improvement ) was achieved in 65 % of patients . The rates of complications and reoperations were similar between groups . Conclusion . The Superion interspinous process spacer relieves symptoms of intermittent neurogenic claudication secondary to moderate LSS in the majority of patients through 2 years . Level of Evidence : Purpose Interspinous process devices ( IPDs ) are implanted to treat patients with intermittent neurogenic claudication ( INC ) based on lumbar spinal stenosis . It is hypothesized that patients with lumbar spinal stenosis treated with IPD have a faster short-term recovery , an equal outcome after 2 years and less back pain compared with bony decompression . Methods A r and omized design with variable block sizes was used , with allocations stratified according to center . Allocations were stored in prepared opaque , coded and sealed envelopes , and patients and research nurses were blind throughout the follow-up . Five neurosurgical centers ( including one academic and four secondary level care centers ) included participants . 211 participants were referred to the Leiden – The Hague Spine Prognostic Study Group . 159 participants with INC based on lumbar spinal stenosis at one or two levels with an indication for surgery were r and omized into two groups . Patients and research nurses were blinded for the allocated treatment throughout the study period . 80 participants received an IPD  and 79 participants underwent spinal bony decompression . The primary outcome at long-term ( 2-year ) follow-up was the score for the Zurich Claudication Question naire . Repeated measurement analyses were applied to compare outcomes over time . Results At two years , the success rate according to the Zurich Claudication Question naire for the IPD group [ 69 % ( 95 % CI 57–78 % ) ] did not show a significant difference compared with st and ard bony decompression [ 60 % ( 95 % CI 48–71 % ) p value 0.2 ] . Reoperations , because of absence of recovery , were indicated and performed in 23 cases ( 33 % ) of the IPD group versus 6 ( 8 % ) patients of the bony decompression group ( p < 0.01 ) . Furthermore , long-term VAS back pain was significantly higher [ 36 mm on a 100 mm scale ( 95 % CI 24–48 ) ] in the IPD group compared to the bony decompression group [ 28 mm ( 95 % CI 23–34 ) p value 0.04 ] . Conclusions This double-blinded study could not confirm the advantage of IPD without bony decompression over conventional ‘ simple ’ decompression , two years after surgery . Moreover , in the IPD treatment arm , the reoperation rate was higher and back pain was even slightly more intense compared to the decompression treatment arm The authors hypothesized that the placement of the interspinous implant would show a similar clinical outcome to the posterior lumbar interbody fusion ( PLIF ) in patients having spinal stenosis with mild segmental instability and that this method would be superior to PLIF without significantly affecting degeneration at the adjacent segments . Forty two adult patients having degenerative spinal stenosis with mild segmental instabilit who underwent implantation of Coflex ™ ( Spine motion , Germany ) or PLIF at L4 - 5 between January 2000 and December 2003 were consecutively selected and studied for one-year clinical outcome . At 12 months after surgery , both groups showed a significant improvement in the visual analogue scale score and Oswestry disability index score for both lower extremity pain and low back pain . However , the range of motion at the upper adjacent segments ( L3 - 4 ) increased significantly after surgery in the PLIF group , which was not manifested in the Coflex ™ group during the follow-up . The authors assumed that interspinous implantation can be an alternative treatment for the spinal stenosis with segmental instability in selected conditions posing less stress on the superior adjacent level than PLIF OBJECT This study was conducted to compare the quality of life ( QOL ) in patients with neurogenic intermittent claudication ( NIC ) secondary to lumbar spinal stenosis ( LSS ) . Using the 36-Item Short Form ( SF-36 ) question naire , the authors compared the results obtained in patients treated with the X STOP Interspinous Process Decompression ( IPD ) System with those obtained in patients who underwent nonoperative therapies . METHODS Patients with LSS were enrolled in a prospect i ve 2-year multicenter study and r and omized either to the X STOP or nonoperative group . The SF-36 survey was used to assess the QOL before treatment and at 6 weeks , 6 months , 1 year , and 2 years posttreatment . An analysis of variance was used to compare individual pre- and posttreatment mean SF-36 domain scores between the two groups and within each treatment group . At all posttreatment time points , the authors observed the following : ( 1 ) mean domain scores in X STOP-treated patients were significantly greater than those in patients treated nonoperatively , with the exception of the mean General Health ( GH ) , Role Emotional , and Mental Component Summary scores at 2 years ; and ( 2 ) mean posttreatment domain scores documented in X STOP-treated patients were significantly greater than mean pretreatment scores , with the exception of mean GH scores at 6 , 12 , and 24 months . CONCLUSIONS The results of this study demonstrate that the X STOP device is significantly more effective than nonoperative therapy in improving the QOL in patients with LSS . The results are comparable with those reported in other studies involving traditional decompressive techniques for LSS and suggest that the X STOP implant can provide an effective treatment compared with nonoperative and conventional surgical therapies Introduction If nonoperative treatment for lumbar stenosis fails , surgery may be considered . This traditionally includes decompression often combined with fusion . Desire for less extensive surgery led to developing new techniques and implants , including an interlaminar device design ed with the goal of providing segmental stability without fusion , following decompression . The purpose of this study was to investigate 5-year outcomes associated with an interlaminar device . Methods This prospect i ve , r and omized , controlled trial was conducted at 21 centers . Patients with moderate to severe lumbar stenosis at one or two contiguous levels and up to Grade I spondylolisthesis were r and omized ( 2:1 ratio ) to decompression and interlaminar stabilization ( D+ILS ; n=215 ) using the coflex ® Interlaminar Stabilization ® device ( Paradigm Spine , LLC ) or decompression and fusion with pedicle screws ( D+PS ; n=107 ) . Clinical evaluations were made preoperatively and at 6 weeks and 3 , 6 , 12 , 18 , 24 , 36 , 48 , and 60 months postoperatively . Overall Food and Drug Administration success criteria required that a patient meet 4 criteria : 1 ) > 15 point improvement in Oswestry Disability Index ( ODI ) score ; 2 ) no reoperation , revision , removal , or supplemental fixation ; 3 ) no major device-related complication ; and 4 ) no epidural steroid injection after surgery . Results At 5 years , 50.3 % of D+ILS vs. 44 % of D+PS patients ( p>0.35 ) met the composite success criteria . Reoperation/revision rates were similar in the two groups ( 16.3 % vs. 17.8 % ; p > 0.90 ) . Both groups had statistically significant improvement through 60 months in ODI scores with 80.6 % of D+ILS patients and 73.2 % of D+PS patients demonstrating > 15 point improvement ( p>0.30 ) . VAS , SF-12 , and ZCQ scores followed a similar pattern of maintained significant improvement throughout follow-up . On the SF-12 and ZCQ , D+ILS group scores were statistically significantly better during early follow-up compared to D+PS . In the D+ILS group , foraminal height , disc space height , and range of motion at the index level were maintained through 5 years . Conclusion Both treatment groups achieved and maintained statistically significant improvements on multiple outcome assessment s throughout 5-year follow-up . On some clinical measures , there were statistically significant differences during early follow-up favoring D+ILS . At no point were there significant differences favoring D+PS . Results of this 5-year follow-up study demonstrate that decompression and interlaminar stabilization with coflex is a viable alternative to traditional decompression and fusion in the treatment of patients with moderate to severe stenosis at one or two lumbar levels . Level of Evidence and Ethical Statements This is a Level I study . Institutional approval was received at each of the sites participating in the trial . Each patient gave informed consent to participate in the trial Study Design The measurement properties and validity of a newly developed patient question naire for the assessment of patients with lumbar spinal stenosis was tested in an ongoing prospect i ve multicenter observational study of patients undergoing decompressive surgery in three teaching hospitals . Objective The goal of the study was to develop a short , self‐administered question naire on symptom severity , physical functional status , and patient satisfaction . Summary of Background Data The measure is intended to complement existing generic measures of spinal‐related disability and health status . The question naire includes three scales with seven questions on symptom severity , five on physical function , and six on satisfaction . Methods The internal consistency of the scales was assessed with Cronbach 's coefficient alpha on crosssectional data from 193 patients before surgery . The test‐retest reliability was assessed on data from a r and om sample of 23 patients using Spearman 's rank correlation coefficient . The responsiveness was assessed on 130 patients with 6‐month follow‐up data using the st and ardized response mean . Results The test‐retest reliability of the scales ranged from 0.82 to 0.96 , the internal consistency from 0.64 to 0.92 , and the responsiveness from 0.96 to 1.07 . The direction , statistical significance , and strength of hypothesized relationships with external criteria were as expected . Conclusions This short self‐administered spinal stenosis measure is reproducible , internally consistent , valid , and highly responsive . It can be used to complement generic instruments in outcome assessment of patients with lumbar spinal stenosis Study Design . Prospect i ve r and omized controlled study . Objective . To compare the outcome of indirect decompression by means of the X-Stop ( Medtronics Inc. , Minneapolis , MN ) implant with conventional decompression in patients with neurogenic intermittent claudication due to lumbar spinal stenosis . Summary of Background Data . Decompression is currently the “ gold st and ard ” for lumbar spinal stenosis but is afflicted with complications and a certain number of dissatisfied patients . Interspinous implants have been on the market for more than 10 years , but no prospect i ve study comparing its outcome with decompression has been performed . Methods . After power calculation , 100 patients were included : 50 in the X-Stop group and 50 in the decompression group . Patients with symptomatic 1- or 2-level lumbar spinal stenosis and neurogenic claudication relieved on flexion were included .  X-Stop operations were performed under local anesthesia . The mean patient age was 69 ( 49–89 ) years , and the male/female distribution was 56/44 . Minimal dural sac area was in all cases except two 80 mm2 or less . The noninferiority hypothesis included 6 , 12 , and 24 months of follow-up , and included . intention-to-treat as well as as-treated analyses . The primary outcome meansure was the Zürich Claudication Question naire , and the secondary outcome measures was the visual analogue scale pain , Short-Form 36 ( SF-36 ) , complications , and reoperations . Results . The primary and secondary outcome measures of patients in both groups improved significantly . The results were similar at 6 , 12 , and 24 months and at no time point could any statistical difference between the 2 types of surgery be identified . Three patients ( 6 % ) in the decompression group underwent further surgery , compared with 13 patients ( 26 % ) in the X-Stop group ( P = 0.04 ) . Results were identical in intention-to-treat and as-treated analyses . Conclusion . For spinal sten 
    Output:
    
IPD implant presented a significantly higher risk of reoperation .
We found low- quality evidence that IPDs result ed in similar outcomes when compared to st and ard decompression surgery .
Patients su bmi tted to IPD implants had significantly higher rates of reoperation , with lower cost-effectiveness .