***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: OBJECT Posterolateral spinal fusion ( PSF ) has long been the st and ard of care for degenerative spondylolisthesis , but less invasive , motion-preserving alternatives have been proposed to reduce the complications associated with fusion while still providing neural decompression and stabilization . The object of the current study is to evaluate the safety and efficacy of coflex Interlaminar Stabilization compared with PSF to treat low- grade spondylolisthesis with spinal stenosis . METHODS This is a prospect i ve , r and omized , multicenter FDA investigational device exemption ( IDE ) trial comparing coflex Interlaminar Stabilization with laminectomy and PSF .  A total of 322 patients from 21 sites in the US were enrolled between 2006 and 2008 for the IDE trial . The current study evaluated only the subset of patients from this overall cohort with Grade 1 spondylolisthesis ( 99 in the coflex group and 51 in the fusion group ) . Subjects were r and omized 2:1 to receive decompression and coflex interlaminar stabilization or decompression and posterolateral spinal fusion with spinal instrumentation . Data collected included perioperative outcomes , Oswestry Disability Index ( ODI ) , back and worse leg visual analog scale ( VAS ) scores , 12-Item Short Form Health Survey , Zurich Claudication Question naire ( ZCQ ) , and radiographic outcomes at a minimum of 2 years . The FDA criteria for overall device success required the following to be met : 15-point reduction in ODI , no reoperations , no major device-related complications , and no postoperative epidural injections . RESULTS At a minimum of 2 years , patient follow-up was 94.9 % and 94.1 % in the coflex and fusion control groups , respectively . There were no group differences at baseline for any demographic , clinical , or radiographic parameter . The average age was 63 years in the coflex cohort and 65 years in the fusion cohort . Coflex subjects experienced significantly shorter operative times ( p < 0.0001 ) , less estimated blood loss ( p < 0.0001 ) , and shorter length of stay ( p < 0.0001 ) than fusion controls . Both groups experienced significant improvements from baseline at 2 years in ODI , VAS back , VAS leg , and ZCQ , with no significant group differences , with the exception of significantly greater ZCQ satisfaction with coflex at 2 years . FDA overall success was achieved in 62.8 % of coflex subjects ( 59 of 94 ) and 62.5 % of fusion controls ( 30 of 48 ) ( p = 1.000 ) . The reoperation rate was higher in the coflex cohort ( 14 [ 14.1 % ] of 99 ) compared with fusion ( 3 [ 5.9 % ] of 51 , p = 0.18 ) , although this difference was not statistically significant . Fusion was associated with significantly greater angulation and translation at the superior and inferior adjacent levels compared with baseline , while coflex showed no significant radiographic changes at the operative or index levels . CONCLUSIONS Low- grade spondylolisthesis was effectively stabilized by coflex and led to similar clinical outcomes , with improved perioperative outcomes , compared with PSF at 2 years . Reoperation rates , however , were higher in the coflex cohort . Patients in the fusion cohort experienced significantly increased superior and inferior level angulation and translation , while those in the coflex cohort experienced no significant adjacent or index level radiographic changes from baseline . Coflex Interlaminar Stabilization is a less invasive , safe , and equally efficacious clinical solution to PSF to treat low- grade spondylolisthesis , and it appears to reduce stresses at the adjacent levels . Clinical trial registration no. : NCT00534235 ( Clinical Trials.gov ) Objective To assess whether interspinous process device implantation is more effective in the short term than conventional surgical decompression for patients with intermittent neurogenic claudication due to lumbar spinal stenosis . Design R and omized controlled trial . Setting Five neurosurgical centers ( including one academic and four secondary level care centers ) in the Netherl and s. Participants 203 participants were referred to the Leiden-The Hague Spine Prognostic Study Group between October 2008 and September 2011 ; 159 participants with intermittent neurogenic claudication due to lumbar spinal stenosis at one or two levels with an indication for surgery were r and omized . Interventions 80 participants received an interspinous process device and 79 participants underwent spinal bony decompression . Main outcome measures The primary outcome at short term ( eight weeks ) and long term ( one year ) follow-up was the Zurich Claudication Question naire score . Repeated measurements were made to compare outcomes over time . Results At eight weeks , the success rate according to the Zurich Claudication Question naire for the interspinous process device group ( 63 % , 95 % confidence interval 51 % to 73 % ) was not superior to that for st and ard bony decompression ( 72 % , 60 % to 81 % ) . No differences in disability ( Zurich Claudication Question naire ; P=0.44 ) or other outcomes were observed between groups during the first year . The repeat surgery rate in the interspinous implant group was substantially higher ( n=21 ; 29 % ) than that in the conventional group ( n=6 ; 8 % ) in the early post-surgical period ( P<0.001 ) . Conclusions This double blinded study could not confirm the hypothesized short term advantage of interspinous process device over conventional “ simple ” decompression and even showed a fairly high reoperation rate after interspinous process device implantation . Trial registration Dutch Trial Register NTR1307 BACKGROUND CONTEXT Few studies have analyzed the results of an interspinous distraction device in patients with lumbar spinal stenosis . It is still unknown whether the outcomes of an interspinous implant are related to the severity of stenosis . PURPOSE To determine the success rate of the Aperius implant and open decompression with the aim of defining better the indications for the two modalities of treatment . STUDY DESIGN Comparison of two cohorts of patients with moderate or severe stenosis treated with the Aperius or by open decompression .  PATIENT SAMPLE The sample comprises 36 patients who had the Aperius implant and 35 who underwent open decompression , both groups followed prospect ively . In the two cohorts , central or lateral stenosis was present in similar proportions , and in both , the patients had pure intermittent claudication or symptoms at rest and on walking . In both groups , preoperative diagnosis was made by magnetic resonance imaging ( MRI ) . OUTCOME MEASURES Patients of both groups were evaluated with the Zurich Claudication Question naire ( ZCQ ) and Oswestry Disability Index . The results were rated as good or poor based on the ZCQ . METHODS The patients of both cohorts were evaluated at 1 month and 3 , 6 , and 12 months after operation , the final follow-up being carried out at least 2 years after surgery . Severity of stenosis was determined based on preoperative MRI scans . In 17 patients of the Aperius group , MRI studies were repeated at the 6-month or final follow-up and compared with the preoperative studies . RESULTS Of the patients in the Aperius group , six had removal of the implant and open surgical decompression at 2 to 17 months after operation ; these patients were considered to have a poor result . At the final follow-up , the result was rated as good in 47 % of all patients who had had the Aperius implant . The percentage of good outcomes was 60 % in moderate stenosis and 31 % in severe stenosis . When considering all not reoperated patients , 57 % had good outcomes ; however , if only the scores in the patient satisfaction domain of the ZCQ were considered , 67 % of these patients were somewhat satisfied with the result of Aperius . No significant relationship was found between patients with pure intermittent claudication and those with leg symptoms also at rest . In 71 % of cases in which preoperative and postoperative MRIs were compared , no significant change in size of the spinal canal was found after operation , whereas in the remaining patients a slight increase in size of the canal was detected . In the open decompression cohort , the results were good in 80 % of cases and poor in 20 % . The outcomes were satisfactory in 69 % of moderate stenosis , with no significant difference with the similar subgroup of the Aperius series . In severe stenosis , the 89 % rate of good results was significantly higher than in the severe Aperius subgroup ( p<.0001 ) . CONCLUSIONS The Aperius interspinous implant is poorly indicated for severe lumbar stenosis , which is significantly improved only in a small minority of cases , whereas decompression procedures ensure high chances of good results . The implant may be indicated for selected patients with moderate stenosis . The outcomes of the Aperius are not influenced by the type of clinical presentation of lumbar stenosis 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 Patients suffering from neurogenic intermittent claudication secondary to lumbar spinal stenosis have historically been limited to a choice between a decompressive laminectomy with or without fusion or a regimen of non-operative therapies . The X STOP Interspinous Process Distraction System ( St. Francis Medical Technologies , Concord , Calif. ) , a new interspinous implant for patients whose symptoms are exacerbated in extension and relieved in flexion , has been available in Europe since June 2002 . This study reports the results from a prospect i ve , r and omized trial of the X STOP conducted at nine centers in the U.S. Two hundred patients were enrolled in the study and 191 were treated ; 100 received the X STOP and 91 received non-operative therapy ( NON OP ) as a control . The Zurich Claudication Question naire ( ZCQ ) was the primary outcomes measurement . Vali date d for lumbar spinal stenosis patients , the ZCQ measures physical function , symptom severity , and patient satisfaction . Patients completed the ZCQ upon enrollment and at follow-up periods of 6 weeks , 6 months , and 1 year . Using the ZCQ criteria , at 6 weeks the success rate was 52 % for X STOP patients and 10 % for NON OP patients . At 6 months , the success rates were 52 and 9 % , respectively , and at 1 year , 59 and 12 % . The results of this prospect i ve study indicate that the X STOP offers a significant improvement over non-operative therapies at 1 year with a success rate comparable to published reports for decompressive laminectomy , but with considerably lower morbidity 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 sten 
    Output:
    
IPD implantation is more effective than the other methods , but not superior to laminectomy in treating NIC