***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 : The BioEnterics ® Intragastric Balloon ( BIB ® ) System in association with restricted diet has been used for the short-term treatment of morbid obesity . Aim of this study was to evaluate the real , short term , efficacy of the BIB for weight reduction in morbidly obese patients by using a prospect i ve , double-blind , r and omised , sham-controlled , crossover study . Methods : Patients were recruited from January 2003 to December 2003 . After selection , they were r and omly allocated into two groups : BIB followed by sham procedure after 3 months ( Group A ) , and sham procedure followed by BIB after 3 months ( Group B ) . All endoscopic procedures were performed under unconscious intravenous sedation . The BioEnterics Intragastric Balloon ( Inamed Health ; Santa Barbara , CA , USA ) was filled by using saline ( 500 ml ) and methylene blue ( 10 ml ) . Patients were discharged with omeprazole therapy and diet ( 1000 kcal ) . Patients were followed up weekly by a physician blinded to r and omisation . In both groups mortality , complications , BMI , BMI reduction and % EWL were considered . Data were expressed as mean±s.d . , except as otherwise indicated . Statistical analysis was performed by means of Student 's t-test , Fisher 's exact test or χ 2 with Yates correction ; P<0.05 was considered significant . Results : A total of 32 patients were selected and entered the study ( 8M/24F ; mean age : 36.2±5.6 years , range 25–50 years ; mean BMI 43.7±1.5 kg/m2 , range 40–45 kg/m2 ; mean % EW : 43.1±13.1 , range : 35–65 ) . All patients completed the study . Mortality was absent . Complications related to endoscopy , balloon placement and removal were absent . Mean time of BIB positioning was 15±2 min , range 10–20 min . After the first 3 months of the study , in Group A patients the mean BMI significantly ( P<0.001 ) lowered from 43.5±1.1 to 38.0±2.6 kg/m2 , while in Group B patients the decrease was not significant ( from 43.6±1.8 to 43.1±2.8 kg/m2 ) . The mean % EWL was significantly higher in Group A than in Group B ( 34.0±4.8 vs 2.1±1 % ; P<0.001 ) . After crossover , at the end of the following 3 months , the BMI lowered from 38.0±2.6 to 37.1±3.4 kg/m2 and from 43.1±2.8 to 38.8±3.1 kg/m2 in Groups A and B , respectively . Conclusions : The results of this study show that treatment of obese patients with BioEnterics Intragastric Balloon  is a safe and effective procedure . In association with appropriate diet it is significantly effective in weight reduction when compared to sham procedure plus diet . The BIB ® procedure can play a role in weight reduction in morbidly obese patients or in the preoperative treatment of bariatric patients OBJECTIVES We sought to evaluate the safety and efficacy of percutaneous transmyocardial revascularization ( PTMR ) in patients with refractory angina caused by one or more chronic total occlusions ( CTOs ) of a native coronary artery . BACKGROUND Previous unblinded , r and omized trials of PTMR in patients with end-stage coronary artery disease and refractory angina have demonstrated significant relief of angina and increased exercise duration . Whether such benefits would be realized in blinded patients with less extensive coronary artery disease is unknown . METHODS A total of 141 consecutive patients with class III or IV angina caused by one or more chronically occluded native coronary arteries in which a percutaneous coronary intervention ( PCI ) had failed were prospect ively r and omized , at 17 medical centers , in the same procedure , to PTMR plus maximal medical therapy ( MMT ) ( n = 71 ) or MMT only ( n = 70 ) . Blinding was achieved through heavy sedation , dark goggles and the concurrent performance of PCI in all patients . RESULTS Baseline characteristics were similar between the two groups . A median number of 20 laser channels were created in patients r and omized to PTMR . At six months , the anginal class improved by two or more classes in 49 % of patients assigned to PTMR and in 37 % of those assigned to MMT ( p = 0.33 ) . The median increase in exercise duration from baseline to six months was 64 s with PTMR versus 52 s with MMT ( p = 0.73 ) . There were no differences in the six-month rates of death ( 8.6 % vs. 8.8 % ) , myocardial infa rct ion ( 4.3 % vs. 2.9 % ) or any revascularization ( 4.3 % vs. 5.9 % ) in the PTMR and MMT groups , respectively ( p = NS for all ) . CONCLUSIONS In patients with class III or IV angina caused by nonrecanalizable CTOs , the performance of PTMR does not result in a greater reduction in angina , improvement in exercise duration or survival free of adverse cardiac events , as compared with MMT only Background Surgical placebos are controversial . This in-depth study explored the design , acceptability , and feasibility issues relevant to design ing a surgical placebo-controlled trial for the evaluation of the clinical and cost effectiveness of arthroscopic lavage  for the management of people with osteoarthritis of the knee in the UK . Methods Two surgeon focus groups at a UK national meeting for orthopaedic surgeons and one regional surgeon focus group ( 41 surgeons ) ; plenary discussion at a UK national meeting for orthopaedic anaesthetists ( 130 anaesthetists ) ; three focus groups with anaesthetists ( one national , two regional ; 58 anaesthetists ) ; two focus groups with members of the patient organisation Arthritis Care ( 7 participants ) ; telephone interviews with people on consultant waiting lists from two UK regional centres ( 15 participants ) ; interviews  with Chairs of UK ethics committees ( 6 individuals ) ; postal surveys of members of the British Association of Surgeons of the Knee ( 382 surgeons ) and members of the British Society of Orthopaedic Anaesthetists ( 398 anaesthetists ) ; two centre pilot ( 49 patients assessed ) . Results There was widespread acceptance that evaluation of arthroscopic lavage  had to be conducted with a placebo control if scientific rigour was not to be compromised . The choice of placebo  surgical  procedure ( three small incisions ) proved easier than the method of anaesthesia ( general anaesthesia ) . General anaesthesia , while an excellent mimic , was more intrusive and raised concerns among some stakeholders and caused extensive discussion with local decision-makers when seeking formal approval for the pilot . Patients were willing to participate in a pilot with a placebo arm ; although some patients when allocated to surgery became apprehensive about the possibility of receiving placebo , and withdrew . Placebo surgery was undertaken successfully . Conclusions Our study illustrated the opposing and often strongly held opinions about surgical placebos , the ethical issues underpinning this controversy , and the challenges that exist even when ethics committee approval has been granted . It showed that a placebo-controlled trial could be conducted in principle , albeit with difficulty . It also highlighted that not only does a placebo-controlled trial in surgery have to be ethically and scientifically acceptable but that it also must be a feasible course of action . The place of placebo-controlled surgical trials more generally is likely to be limited and require specific circumstances to be met . Suggested criteria are presented . Trial registration numberThe trial was assigned IS RCT N02328576 through http://controlled-trials.com/ in June 2006 . The first patient was r and omised to the pilot in July 2007 BACKGROUND & AIMS Ablation of gastric inlet patches ( GIP ) in the cervical esophagus by argon plasma coagulation ( APC ) can alleviate chronic globus sensations in the throat . We investigated the efficacy of this therapy in a r and omized , controlled multicenter trial . METHODS Patients with chronic globus sensations and GIP were r and omly assigned 1:1 to groups that were treated with APC or a sham procedure ( controls ) . Patients and their referring physicians were blinded to therapy . All patients completed a st and ardized question naire about symptoms before and 3 months after the procedure . Thereafter , control patients were eligible for cross-over therapy . Long-term efficacy was assessed in all patients > or=6 months after APC . RESULTS Improvement of symptoms was reported in 9 ( 82 % ) of 11 patients who received APC , compared with 0 ( 0 % ) of 10 patients in the control group ( P = .002 ) . Nine ( 90 % ) of 10 patients treated with APC had per protocol healing , compared with 0 ( 0 % ) of 9 controls ( P < .001 ) . Scores for symptom/globus assessment significantly improved in patients in the APC group , whereas patients in the control group did not perceive any symptom relief . Eight of the 10 patients who started in the control group crossed over to the APC group . Long-term efficacy ( after a median follow-up of 17 months ) was documented in 13 ( 76 % ) of 17 treated patients . CONCLUSIONS Ablation of gastric inlet patches appears to be an effective therapy for alleviation of associated globus sensations . This new treatment modality might change the paradigm for treatment of these patients Background : Alzheimer disease ( AD ) has been associated with abnormal cerebral clearance of macromolecules , such as amyloid and microtubule-associated-protein tau ( MAP-τ ) . We hypothesized that improving clearance of macromolecules from the CNS might slow the progression of dementia . Objective : This prospect i ve , r and omized , double-blinded , placebo-controlled trial evaluated the safety and effectiveness of a surgically implanted shunt in subjects with probable AD . Methods : A total of 215 subjects with probable AD by National Institute of Neurological Disorders and Stroke – Alzheimer ’s Disease and Related Disorders Association criteria received either a low-flow ventriculoperitoneal shunt or a sham ( occluded ) shunt for 9 months . Longitudinal CSF sampling was performed in both active and control subjects . Primary outcome measures were the Mattis Dementia Rating Scale and the Global Deterioration Scale . CSF Aβ(1 - 42 ) and MAP-τ also were assayed . Results : After a planned interim analysis , the study was halted for futility . Using the intent-to-treat population , no between-group differences were observed in the primary outcome measures . The surgical procedure and device were associated with 12 CNS infections , some temporally associated with CSF sampling . All were treated successfully . Conclusions : We found no benefit to low-flow CSF shunting in subjects with mild to severe Alzheimer disease .  CSF infections , while treatable , occurred more frequently than expected , in some cases likely related to CSF sampling . GLOSSARY : Aβ = amyloid beta-peptides ; AD = Alzheimer disease ; ADCS-ADL = AD Cooperative Study Activities of Daily Living ; BBB = blood – brain barrier ; CP = choroid plexus ; FDA = Food and Drug Administration ; GDS = Global Deterioration Scale ; GEE = Generalized Estimating Equations ; IA = interim analysis ; ISF = interstitial fluid ; ITT = intent-to-treat ; LRP-1 = lipoprotein receptor-related protein-1 ; MAP-τ = microtubule-associated-protein tau ; MDRS = Mattis Dementia Rating Scale ; MMSE = Mini-Mental State Examination ; NAART = North American Adult Reading Test ; NINCDS-ADRDA = National Institutes of Neurological and Communicative Diseases and Stroke – Alzheimer ’s Disease and Related Disorders Association ; NPH = normal-pressure hydrocephalus ; PHF = perihippocampal fissures ; RAGE = receptor for advanced glycation end-products ; SADAS-Cog = St and ardized AD Assessment Scale – Cognitive ; SAE = serious adverse events OBJECTIVE To examine the effect on pain and quality of life for women with all stages of endometriosis undergoing laparoscopic surgery  compared with placebo surgery . DESIGN A r and omized , blinded , crossover study . SETTING A tertiary referral unit in a district general hospital . PATIENT(S ) Thirty-nine women with histologically proven endometriosis completed the 12-month study . INTERVENTION(S ) Women were r and omized to receive initially either a diagnostic procedure ( the delayed surgical group ) or full excisional surgery ( the immediate surgery group ) . After 6 months , repeat laparoscopy was performed , with removal of any pathology present . MAIN OUTCOME MEASURE(S ) The end points were changes from baseline values of visual analogue pain scores , vali date d quality -of-life instruments ( EQ-5D and SF-12 ) , and sexual activity question naire scores . Patients and assessors of outcomes were blinded to the treatment-group assignment . RESULT ( S ) Significantly more of the 39 women operated on according to protocol reported symptomatic improvement after excisional surgery than after placebo : 16 of 20 ( 80 % ) vs. 6 of 19 ( 32 % ) ; chi(2 
    Output:
    
The main problem reported in many trials was a very slow recruitment rate , mainly due to the difficulty in finding eligible patients .
This review demonstrated that placebo-controlled surgical trials are feasible , at least for procedures with a lower level of invasiveness , but also that recruitment is difficult .
Many of the presumed challenges to undertaking such trials , for example , funding , anaesthesia or blinding of patients and assessors , were not reported as obstacles to completion in any of the review ed trials