***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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    Input: HYPOTHESIS Infectious complications are the main causes of postoperative morbidity in abdominal surgery . Identification of risk factors , which could be avoided in the perioperative period , may reduce the rate of postoperative infectious complications . DESIGN A data base was established from 3 prospect i ve , r and omized , multicenter studies . Multivariate analysis was performed using nonconditional logistic regression expressed as an odds ratio ( OR ) . SETTING Multicenter studies ( ie , private medical centers , institutional hospitals , and university hospitals ) . PATIENTS From June 1982 to September 1996 , a data base was established containing the information of 4718 patients who underwent noncolorectal abdominal surgery .  MAIN OUTCOME MEASURES The dependent variables studied included surgical site infection ( SSI ) ( divided into parietal and deep infectious complications with or without fistulas ) and global infectious complications ( SSI and extraparietal and abdominal infectious complications ) . RESULTS The rate of global infectious complications was 13.3 % ; SSI , 4.05 % ; parietal infectious complications , 2.2 % ; deep infectious complications with fistulas , 2.18 % ; and deep infectious complications without fistulas , 1.38 % . In multivariate analysis , the following 7 independent risk factors for global infectious complications have been identified : age ( 60 - 74 years , OR , 1.64 ; > or=75 years , OR , 1.45 ) ; being underweight ( OR , 1.51 ) ; having cirrhosis ( OR , 2.45 ) , having a vertical abdominal incision ( OR , 1.66 ) ; having a suture placed or an anastomis of the bowel ( OR , 1.48 ) in the digestive tract ; having a prolonged operative time ( 61 - 120 minutes , OR , 1.66 ; 121 minutes , OR , 2.72 ) ; and being categorized as having a class 4 surgical site ( ie , obese patients or having a risk factor of a healing defect ) ( OR , 1.66 ) .  Ceftriaxone sodium therapy  was identified as a protective factor ( OR , 0.43 ) . In multivariate analysis , the following 5 independent risk factors for SSI have been identified : the existence of a preoperative cutaneous abscess or cutaneous necrosis ( OR , 4.75 ) , having a suture placed or an anastomosis of the bowel ( OR , 1.82 ) in the digestive tract , having postoperative abdominal drainage ( OR , 2.15 ) , undergoing a surgical procedure for the treatment of cancer ( OR , 1.74 ) , and receiving curative anticoagulant therapy ( OR , 3.33 ) postoperatively . CONCLUSIONS Our data show that risk factors for SSI and for global infectious complications are disparate . Indeed , only the placement of a suture or having an anastomosis of the bowel in the digestive tract is a risk factor for both SSI and global infections . Some of these factors may be modifiable before or during the surgical procedure to reduce the infection rate or to prevent postoperative complications BACKGROUND This study was design ed to determine the effectiveness of Hemaseel APR fibrin sealant versus conventional drain placement in the prevention of seromas after breast procedures . METHODS A prospect i ve , r and omized , controlled study of subjects who were r and omized into control ( drain ) and experimental ( fibrin ) groups was conducted . RESULTS Analysis of 82 patients showed similarly matched groups . Seroma formation rate was 45.5 % in the control group and 36.8 % in the fibrin glue group ( P = 0.43 ) . The rate of wound complications was similar . Aspirate volumes were significantly greater in the fibrin glue group . Drain placement saved patients > 366 US dollars over fibrin glue . CONCLUSIONS Although use of fibrin sealant result ed in a nonsignificant decrease in seroma formation rate compared with that of drain placement , the higher cost involved , cumbersome technique , and higher aspirate volumes tend to indicate that there is no advantage to using fibrin glue over drain placement with the technique described Background : The most frequent complication after  bilateral reduction mammoplasty ( BRM ) is the formation of seromas and hematomas . If a group of patients who are at increased risk of seroma and hematoma are identified , the use of drains in this group would be beneficial . We hypothesized that superior pedicle reductions would have increased postoperative drainage . Methods : A prospect i ve observational study was conducted to identify independent risk factors for increased drainage after BRM . Blinded research nurses were employed to record the amount of drainage during the postoperative period . Univariate and multivariate regression analyses were used to identify risk factors for increased postoperative drainage . Results : The study included a total of 111 patients . Univariate analysis identified the amount of preoperative infiltration ( P < 0.001 ) , the amount of liposuction ( P < 0.001 ) , the amount of surgically resected tissue ( P = 0.001 ) , the type of reduction ( P < 0.001 ) , the patient 's chest circumference ( P = 0.035 ) , and the patient 's body mass index ( BMI ) ( P = 0.015 ) as significant predictors of postoperative drainage . Multivariate regression analysis identified the amount of tissue resected and the type of reduction as the only 2 independent predictors of postoperative drainage . The use of superior pedicle technique predicted 43 % of the variability in postoperative wound drainage . Conclusions : The use of the superior pedicle technique for BRM is associated with a significant increase in postoperative drainage . Surgeons using this technique should consider the routine use of drains to avoid possible complications of seroma , infection , and poor wound healing Background : For some patients , removal of surgical drains can be the most painful part of surgery . The authors present a prospect i ve , r and omized , patient-controlled study comparing soft fluted silicone ( Blake ) drains with conventional rigid ( Portavac ) drains . Methods : After ethical committee approval , 43 patients undergoing bilateral breast reduction surgery were recruited into the study . A Blake drain was inserted on one side and a Portavac drain was inserted on the contralateral side ; the patients therefore acted as their own controls . Pain scores were measured on a descriptive scale 10 minutes before , during , and 10 minutes after drain removal . Statistical analysis was carried out using the Wilcoxon signed ranks matched pairs test . Results : The results show that Blake drains are less painful before ( p = 0.05 ) , during ( p = 0.01 ) , and after removal ( p = 0.009 ) . Of those patients who expressed a preference , 27 preferred the Blake drain and 10 preferred the Portavac drain . Conclusion : The authors advocate the use of a silicone fluted ( Blake ) drain for any wound requiring drainage , especially if large-caliber drains are indicated One hundred and seven bilateral breast reductions were prospect ively r and omised during surgery to receive or not receive wound drains . Fifty-five patients were r and omised to have a drain and 52 to not have a drain . There was no statistical difference in the number of complications between the drained and undrained group ( P=0.092 ; student 's t-test for independent observations ) . Twenty-two of the 55 patients in the drained group had a complication , 12 of the 52 patients in the undrained group had a complication . The hospital stay was significantly shorter ( P<0.001 ) in the undrained group . The main discomfort score due to the presence of the drains was 5.62 , which can be qualified as high . This study demonstrates that breast reduction without postoperative draining does not increase the risk of complications , increases the patient 's comfort and significantly reduces hospital stay A prospect i ve , r and omized study was design ed to compare the outcome of inferior pedicle/Wise pattern reduction ( group I ) with medial pedicle/vertical pattern reduction ( group II ) in moderate resections averaging 500 g per breast . There were 105 women in group I and 103 women in group II . All surgical procedures were performed by the same plastic surgeon . Patient information recorded included age , body mass index , type of surgery , weight of specimen , need for surgical revision , and complications . Six months postoperatively the patients were asked to complete a question naire , which rated their satisfaction with the surgical outcome . The question naire used a 10-point response format ranging from very disappointed ( score of 1 ) to very pleased ( score of 10 ) . The results demonstrated that there was no significant difference between the groups in age ( 31 ± 12 versus 29 ± 13 years ) , body mass index ( 26 ± 4 versus 27 ± 5 ) , and amount of tissue excised ( 553 ± 203 g versus 548 ± 205 g ) . Group I required no surgical revisions , but in group II revisions for dog-ears were required in 11 percent . The rate of other complications was similar in both groups . Patients ’ evaluations of breast size , shape , symmetry , nipple sensation , symptom relief , ease of brassiere/clothing fitting , and overall satisfaction were not significantly different . The vertical mammaplasty was ranked significantly ( p < 0.05 ) higher by patients in regard to scars ( 6 ± 2 versus 3 ± 3 ) and overall aesthetic results ( 8 ± 1 versus 6 ± 3 ) . In the management of moderate macromastia , this study indicates that patients who have a vertical reduction are less disappointed with the scars but require a significantly higher rate of surgical revisions compared with patients who have a Wise pattern reduction In a prospect i ve r and omised study 30 mongrel rabbits received two st and ard colon-resections . Three types of drains were tested : ( latex-rubber- ) Penrose-drains , rubbertube- and silicontube-drains , which were placed in the lower abdomen . As a closed drainage-system the extraperitoneal tip of the drain was placed in a closed subcutis-pocket . One of the two colon-anastomoses also was drained . The findings were recorded on the 7th postoperative day . A single mechanic alteration was found , an ulcer caused by a silicon-drain , that pushed against the abdominal wall . The other signs of mechanic irritation were microscopically unspecified inflammatory reactions to the foreign body drain . There was no ascending infection caused by the drain . All infections came from complications of the colon resections . In contrast to common opinions the drains in the lower abdomen showed no adhesions to the abdominal wall or organs . Only the entrance of the drain into the peritoneum and the cotton-gaze of Penrose-drains showed in nearly all cases adhesions . The large amount of adhesions to the anastomosis-drains came from complications of the colon-anastomoses . As a cause of material , rubber- and latex-rubber-drains showed large fibrin-clots on their surfaces . 7 days after the operation only about 20 % of the drains had sufficient function . The rest was occluded by fibrin-clots in the lumen of the drain or the cotton-gaze . Over all there is no difference in changes and effects of the three different types of drains , but silicon as material showed advantages Methods for combining data from several studies exist and appear to be quite useful . None satisfactorily addresses the question of what studies should be combined . This issue is the most serious method ological limitation . Even studies with statistically significant interaction might still be combined if the effect were in the same direction . Thus , substantial scientific input is required as to what criteria must be met by each potential study . Much can be learned from combining or pooling data but it must be done cautiously . Pooling exercises do not replace well design ed prospect i ve clinical trials . Efforts for establishing basic design criteria to allow for multicentre and multicountry trials to be more easily combined might be useful . BACKGROUND Seromas of the axillary space following breast surgery can lead to significant morbidity and delay in the initiation of adjuvant therapy . A prospect i ve , r and omized study was undertaken to evaluate the effect of bovine spray thrombin on seroma formation following either modified radical mastectomy ( MRM ) or lumpectomy with axillary dissection ( LAD ) . In addition , risk factors for seroma formation were analyzed and identified . METHODS A total of 101 patients were r and omized to receive either bovine thrombin ( 20,000 units ) ( treatment group ) or no thrombin ( control group ) applied to their axilla following either MRM or LAD . Drains were left in place until the preceding 24-hour drainage was < 40 milliliters . The number of days the drains were in place and wound complications ( including seroma formation ) were recorded . RESULTS Forty-nine ( n = 49 ) patients were assigned to the treatment gorup and 52 ( n = 52 ) to the control group . MRM was performed on 60 patients ( 59 % ) and LAD oN 41 ( 41 % ) . Eighteen of the 49 patients ( 37 % ) in the thrombin group developed a seroma in comparison to 21 of the 52 control patients ( 40 % ) ( P = 0.71 ) . Significant risk factors for seroma formation included increased age , patient weight , initial 72-hour wound drainage , and LAD . No statistically significant differences were observed between treatment and control groups with respect to time to drain removal , or the incidence of other wound complications . CONCLUSION Although thrombin by itself appears to 
    Output:
    
The limited evidence available shows no significant benefit of using post-operative wound drains in reduction mammoplasty , though hospital stay may be shorter when drains are not used .