***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: BACKGROUND Despite more than three decades of research on iatrogenesis , surgical adverse events have not been subjected to detailed study to identify their characteristics . This information could be invaluable , however , for guiding quality assurance and research efforts aim ed at reducing the occurrence of surgical adverse events . Thus we conducted a retrospective chart review of 15,000 r and omly selected admissions to Colorado and Utah hospitals during 1992 to identify and analyze these events . METHODS We selected a representative sample of hospitals from Utah and Colorado and then r and omly sample d 15,000 nonpsychiatric discharges from 1992 . With use of a 2-stage record- review process modeled on previous adverse event studies , we estimated the incidence , morbidity , and preventability of surgical adverse events that caused death , disability at the time of discharge , or prolonged hospital stay . We characterized their distribution by type of injury and by physician specialty and determined incidence rates by procedure . RESULTS Adverse events were no more likely in surgical care than in nonsurgical care . Nonetheless , 66 % of all adverse events were surgical , and the annual incidence among hospitalized patients who underwent an operation or child delivery was 3.0 % ( confidence interval 2.7 % to 3.4 % ) . Among surgical adverse events 54 % ( confidence interval 48.9 % to 58.9 % ) were preventable . We identified 12 common operations with significantly elevated adverse event incidence rates that ranged from 4.4 % for hysterectomy ( confidence interval 2.9 % to 6.8 % ) to 18.9 % for abdominal aortic aneurysm repair ( confidence interval 8.3 % to 37.5 % ) . Eight operations also carried a significantly higher risk of a preventable adverse event : lower extremity bypass graft ( 11.0 % ) , abdominal aortic aneurysm repair ( 8.1 % ) , colon resection ( 5.9 % ) , coronary artery bypass graft/cardiac valve surgery ( 4.7 % ) , transurethral  resection of the prostate or of a bladder tumor ( 3.9 % ) , cholecystectomy ( 3.0 % ) , hysterectomy ( 2.8 % ) , and appendectomy ( 1.5 % ) . Among all surgical adverse events , 5.6 % ( confidence interval 3.7 % to 8.3 % ) result ed in death , accounting for 12.2 % ( confidence interval 6.9 % to 21.4 % ) of all hospital deaths in Utah and Colorado . Technique-related complications , wound infections , and postoperative bleeding produced nearly half of all surgical adverse events . CONCLUSION These findings provide direction for research to identify the causes of surgical adverse events and for targeted quality improvement efforts OBJECTIVE Our objective was to define the relationship between surgical technical performance score , intraoperative adverse events , and major postoperative adverse events in complex pediatric cardiac repairs . METHOD Infants younger than 6 months were prospect ively followed up until discharge from the hospital . Technical performance scores were grade d as optimal , adequate , or inadequate based on discharge echocardiograms and need for reintervention after initial surgery . Case complexity was determined by Risk Adjustment in Congenital Heart Surgery ( RACHS-1 ) category , and preoperative illness severity was assessed by Pediatric Risk of Mortality ( PRISM ) III score . Intraoperative adverse events were prospect ively monitored . Outcomes were analyzed using nonparametric methods and a logistic regression model . RESULTS A total of 166 patients ( RACHS 4 - 6 [ 49 % ] ) , neonates [ 50 % ] ) were observed . Sixty-one ( 37 % ) had at least 1 intraoperative adverse event , and 47 ( 28.3 % ) had at least 1 major postoperative adverse event . There was no correlation between intraoperative adverse events and RACHS , preoperative PRISM III , technical performance score , or postoperative adverse events on multivariate analysis . For the entire cohort , better  technical performance score  result ed in lower postoperative adverse events , lower postoperative PRISM , and lower length of stay and ventilation time ( P < .001 ) . Patients requiring intraoperative revisions fared as well as patients without , provided the technical score was at least adequate . CONCLUSIONS In neonatal and infant open heart repairs ,  technical performance score  is one of the main predictors of postoperative morbidity . Outcomes are not affected by intraoperative adverse events , including surgical revisions , provided technical performance score is at least adequate Objective To determine the association between surgeons ’ experience and postoperative complications in  thyroid surgery .  Design Prospect i ve cross sectional multicentre study . Setting High volume referral centres in five academic hospitals in France . Participants All patients who underwent a thyroidectomy undertaken by every surgeon in these hospitals from 1 April 2008 to 31 December 2009 . Main outcome measures Presence of two permanent major complications ( recurrent laryngeal nerve palsy or hypoparathyroidism ) , six months after thyroid surgery . We used mixed effects logistic regression to determine the association between length of experience and postoperative complications . Results 28 surgeons completed 3574 thyroid procedures during a one year period .  Overall rates of recurrent laryngeal nerve palsy and hypoparathyroidism were 2.08 % ( 95 % confidence interval 1.53 % to 2.67 % ) and 2.69 % ( 2.10 % to 3.31 % ) , respectively . In a multivariate analysis , 20 years or more of practice was associated with increased probability of both recurrent laryngeal nerve palsy ( odds ratio 3.06 ( 1.07 to 8.80 ) , P=0.04 ) and hypoparathyroidism ( 7.56 ( 1.79 to 31.99 ) , P=0.01 ) . Surgeons ’ performance had a concave association with their length of experience ( P=0.036 ) and age ( P=0.035 ) ; surgeons aged 35 to 50 years had better outcomes than their younger and older colleagues . Conclusions Optimum individual performance in thyroid surgery can not be passively achieved or maintained by accumulating experience . Factors contributing to poor performance in very experienced surgeons should be explored further Background  Preoperative radiotherapy reduces recurrence rates after surgery for rectal cancer but other variables may also affect outcome . The Stockholm Rectal Cancer Study Group has conducted two prospect i ve r and omized trials on preoperative radiotherapy in rectal cancer Objective : This study determined the incidence , type , nature , preventability and impact of adverse events ( AEs ) among hospitalised patients and potentially preventable deaths in Dutch hospitals . Methods : Using a three-stage retrospective record review process , trained nurses and doctors review ed 7926 admissions : 3983 admissions of deceased hospital patients and 3943 admissions of discharged patients in 2004 , in a r and om sample of 21 hospitals in the Netherl and s ( 4 university , 6 tertiary teaching and 11 general hospitals ) . A large sample of deceased patients was included to determine the occurrence of potentially preventable deaths in hospitals more precisely . Results : One or more AEs were found in 5.7 % ( 95 % CI 5.1 % to 6.4 % ) of all admissions and a preventable AE in 2.3 % ( 95 % CI 1.9 % to 2.7 % ) . Of all AEs , 12.8 % result ed in permanent disability or contributed to death . The proportion of AEs and their impact increased with age . More than 50 % of the AEs were related to surgical procedures . Among deceased hospital patients , 10.7 % ( 95 % CI 9.8 % to 11.7 % ) had experienced an AE . Preventable AEs that contributed to death occurred in 4.1 % ( 95 % CI 3.5 % to 4.8 % ) of all hospital deaths . Extrapolating to a national level , between 1482 and 2032 potentially preventable deaths occurred in Dutch hospitals in 2004 . Conclusions : The incidence of AEs , preventable AEs and potentially preventable deaths in the Netherl and s is substantial and needs to be reduced . Patient safety efforts should focus on surgical procedures and older patients Background The aim of this multicenter retrospective study was to establish background data for future r and omized clinical trial comparing open and laparoscopy-assisted gastrectomies ( LAGs ) . We sought to evaluate the technical feasibility of LAG by determining the morbidity and mortality and identifying corresponding predictive factors . Patients and Methods A retrospective multicenter study was carried out in Korea on 1,485 patients in who , LAG had been attempted for gastric cancer under the care of ten surgeons , at ten institutions , during the period spanning May 1998 to December 2005 .  Patient characteristics , operative outcomes , and postoperative morbidities and mortalities were analyzed . Results Overall morbidity and mortality rates were 14.0 % and 0.6 % , respectively . Complications included : wound problem ( 4.2 % , n = 62 ) , intraluminal bleeding ( 1.3 % , n = 20 ) , intra-abdominal abscess or fluid collection ( 1.3 % , n = 19 ) , anastomotic leakage ( 1.3 % , n = 18 ) , and intra-abdominal bleeding ( 1.3 % , n = 18 ) . By using multivariate analysis we found that the two most important risk factors associated with postoperative complications were presence of comorbidity in the patient and lack of experience on the part of the surgeon . Conclusion LAG is a technically feasible , safe , and effective method for treating patients with gastric cancer . Extra caution in patients with comorbidities , and dedication to improving surgical proficiency in LAG , may decrease the risk of complications . Through this study , we have established the inclusion criteria for LAG . For our multicenter , prospect i ve , r and omized trials ( NCT00452751 ) , potential patients should have an American Society of Anesthesiology ( ASA ) score of less than 3 , and surgeons performing the procedures should have experience with more than 50 cases of LAG Background Few studies to date have directly compared outcomes of  retropubic ( RRP ) and laparoscopic ( LRP ) radical prostatectomy .  We investigated a single institution experience with RRP and LRP with respect to functional and pathological outcomes . Methods 168 patients who underwent RRP were compared to 171 patients who underwent LRP at our institution . Pathological and functional outcomes including postoperative urinary incontinence and erectile dysfunction ( ED ) of the two cohorts were examined . Results Patients had bilateral , unilateral and no nerve sparing technique performed in 83.3 % , 1.8 % and 14.9 % of cases for RRP and 23.4 % , 22.8 % and 53.8 % of cases for LRP , respectively ( p < 0.001 ) . Overall positive surgical margin rates were 22.2 % among patients who underwent RRP compared to 26.5 % of patients who underwent LRP ( p = 0.435 ) . Based upon pads/day , urinary continence postoperatively was achieved in 83.2 % and 82.8 % for RRP and LRP , respectively ( p = 0.872 ) . Analysis on postoperative ED was limited due to lack of information on the preoperative erectile status . However , postoperatively there were no differences with respect to ED between the two cohorts ( p = 0.151 ) . Based on ICIQ-scores , surgeons with more experience had lower rates of postoperative incontinence irrespective of surgical technique ( p = 0.001 and p < 0.001 for continuous and stratified data , respectively ) . Conclusions RRP and LRP represent effective surgical approaches for the treatment of clinical ly localized prostate cancer . Pathological outcomes are excellent for both surgical techniques . Functional outcomes including postoperative urinary incontinence and ED are comparable between the cohorts . Surgeon experience is more relevant than surgical technique applied Two hundred and fifty patients undergoing elective surgical treatment involving anastomoses of the left side of the colon or colon and rectum have been studied in a r and omized trial in which the EEA ( U. S. Surgical Corp. ) circular stapler has been compared with single layer sutured anastomoses .  Only patients in whom either technique was feasible were included in the analysis . The operative techniques were largely st and ardized . Patients were studied by means of a limited barium enema on the ninth or tenth postoperative day . The data have been analyzed for leakage rate ( clinical and roentgenologic ) , other complications and degree of experience of the surgeon .  Eleven patients were excluded from the analysis because the selected technique could not be carried out ; of these , eight were in the stapled group in which it was possible to perform a sutured anastomosis . There were no instances in which it was possible to staple but not possible to suture . The remaining three exclusions were patients in whom either a coloanal anastomosis or a Hartmann procedure was performed . There was no over-all difference in the leakage rate -- roentgenologic , clinical or total -- between the two groups . However , when analyzed by the surgeon , the clinical leakage rate for surgeons in training was greater for sutured anastomoses than 
    Output:
    
Conclusions : The results of this systematic review demonstrated that superior technical performance positively affects patient outcomes .