most of the patients diagnosed with breast cancer will undergo surgery , with a significant risk of complications . these complications , although they are often minor , affect 30% of all patients and entail such adverse effects as impaired quality of life , delays in adjuvant therapy , higher costs , and increased duration of hospitalization . the most common adverse effects are hematoma ( 210% ) , seroma ( 1085% ) , and surgical site infection ( ssi ) ( 0.845.8% ) [ 1 , 2 ] . the measures used to prevent these nosocomial infections include prophylactic antibiotic treatment , preoperative preparation of the patient , and respect for the rules of asepsis and postoperative care protocols . most of these measures have been formally evaluated and proven to be valuable ; however , there is still a need for improved prevention of surgical complications , especially those involving infectious matters [ 35 ] . suture material is known to be a potential agent of infection [ 69 ] . to prevent microbial colonization of suture material in operative wounds , triclosan - coated polyglactin 910 suture materials with antibacterial activity ( vicryl plus and monocryl plus ethicon gmbh , nordersdedt , germany ) have been developed . triclosan ( tc ) is a broad - spectrum phenol family antiseptic , used for more than 30 years as a safe and effective antimicrobial agent , against the most common pathogen agents that cause ssi : s. aureus and s. epidermidis . the antimicrobial efficacy of this material in reducing both bacterial adherence to the suture and microbial viability have been proven in vitro [ 11 , 12 ] and in animal models [ 1315 ] . coated sutures with tc were compared clinically to nonimpregnated suture material in extragynecological surgery , and were shown to perform as well or better than traditional sutures with respect to intraoperative handling and wound healing in pediatric general surgery , pediatric neurosurgery , thoracic , and abdominal surgery [ 19 , 20 ] . however , other studies suggest that tc - coated sutures could be inefficient or might have potential adverse effects as wound dehiscence , and should be used with caution [ 21 , 22 ] . recently , two studies have tried to use tc - coated suture in breast surgery , and showed better cosmetic outcomes and efficiency in reducing ssi [ 23 , 24 ] . the aim of the current study was to assess the incidence of both suture - related complications ( src ) and surgical site infections ( ssi ) between two populations : those with and without the use of triclosan - coated vicryl plus . we analysed prospectively collected data in two identical summer periods at tenon hospital , paris , france . during the first period , from june to august 2009 , 92 patients underwent breast surgery with conventional sutures ( group 1 ) . from june to august 2010 , 98 patients underwent breast surgery with tc - coated sutures ( group 2 ) . all the women gave informed written consent to the therapeutic procedures and to the analysis of data related to their pathology . details regarding patient characteristics including body mass index ( bmi ) , national nosocomial infections surveillance ( nnis ) status , diabetes mellitus status , and tobacco consumption were collected prospectively . complementary data obtained from patient files included patient sociodemographic characteristics , tumoral characteristics , peri- and postoperative data . patients were followed up at 15 and 30 days after discharge but could have been seen in an emergency . we recorded src , which included ssi ( including fever , wound discharge , and surgical site infection ) , and   cutaneous complications ( including delay to wound healing and wound dehiscence , allergy , and necrosis ) . ssi within the 30 first days after surgery was considered to be related to surgery and was classified in terms of severity of the infection , according to the french recommendations for nosocomial infections . all patients underwent preoperative chlorexidine skin cleansing and skin preparation with double chlorexidine washing . during the first period ( group 1 ) , we used classical sutures ( vicryl and monocryl , ethicon ) , and during the second period ( group 2 ) we used sutures coated with tc ( vicryl plus and monocryl plus , ethicon ) . prophylactic antibiotic treatment was performed according to the anesthesiology unit protocol : no systematic treatment in case of conservative surgery or cefazoline 2  g iv during mastectomy or axillary lymphadenectomy . the endpoint was to compare src between two populations , with and without tc - coated sutures . we used prediction of expected src among the tc - treated population , based on the characteristics of this population . qualitative variables were compared with the chi - square test or fisher 's exact test . a t - test was used for continuous variables , if normality could be assumed . all reported tests were two - sided ( p  0.05 was considered significant ) . we performed subgroups analyses in patients with known risk factors of infection to determine if some patients may benefit from tc - coated sutures . all significant variables in the univariate analysis were subjected to logistic regression , as were factors used in the literature ( age , diabetes , and bmi ) to assess independent predictors of breast surgery complications . akaike information criteria ( aic ) was used to perform backward stepwise variable selection among group 1 . discrimination was quantified with the area under the receiver operating characteristic curve ( auc ) . the results are displayed in a calibration graph that shows the relationship between the observed outcome frequencies and the predicted probabilities for two groups of patients categorized according to a median split ( semicohorts with the lowest / highest predicted complication rate ) . therefore , a sensible measure of calibration ( the unreliability index ) is a likelihood ratio statistic testing the null hypothesis that a = 0 and b = 1 . to evaluate the efficiency of tc - coated sutures , we compared individual predicted probabilities of complications using the model versus observed complication rate in group 2 . the treatment was considered efficient if observed probabilities were lower than predicted , not efficient if they were equal , and harmful if the observed rate of complications was greater than the predicted rate . during these two periods , 190 patients underwent breast surgery . among them , wound closure was performed with traditional suture material in 92 ( group 1 ) and with tc - coated sutures in 98 ( group 2 ) . patients were similar in both groups with respect to sociodemographic and tumoral characteristics ( table 1 ) . there were no significant differences for the type of surgery , the rate of drainage placement and duration , and the antibiotic prophylactic treatment . patients in group 2 had a higher median operative duration ( 80  min versus 60  min , p < 0.001 ) . the src rates were 13% ( 12/92 ) in group 1 and 8% ( 8/98 ) in group 2 . this difference was not significantly different ( p = 0.3 ) ( table 2 ) . ssi occurred in 10 patients with classical sutures ( 11% ) and in 6 patients whose wounds were closed by tc - coated sutures ( 6% ) ( p = 0.2 ) . results are reported in figure 1 as a forest plot representing odds ratios and their confidence intervals for subgroups . however , tc - coated sutures had a significant protective effect against src only in multifocal tumors . the protective effect fell short of reaching statistical significance in case of age > 55 axillary dissection and duration of surgery > 60  min . this latter analysis suggest that a model - based approach may help selecting patient for a benefit of tc - coated sutures . in univariate analysis , significant risk factors for src in group 1 were conservative surgery , axillary lymphadenectomy , axillary drainage , breast drainage duration , postoperative anticoagulation , and multifocality . based on a multivariate analysis , we developed a model to predict individual risk of src , using variables and interaction , which increase akaike information criteria ( axillary lymphadenectomy and age in our model ) . the auc obtained with this logistic regression model in the training population was 0.88 ( 95% ci 0.770.95 ) ; after bootstrap validation , the auc was 0.86 ( p < 10 ) ( figure 2 ) . we calculated the individual probability of complication with a specific model built based on the data from group 1 . overall , the observed rates of complication were not concordant with predictions in this subgroup , as demonstrated by discrimination and calibration . discrimination assessed by auc did not reach statistical significance ( auc = 0.65 , p = 0.08 ) ( figure 2 ) . the calibration curve was unsatisfactory ( figure 3 ) : there was a significant difference between predicted probabilities and observed percentages . in figure 3 , patients were separated in two subgroups according to their predicted probability of complications ( x - axis ) : low risk for predicted risk < 10% and high risk for predicted risk 10% . perfect predictions are plotted on the ideal line : intercept at ( 0 , 0 ) , slope : 45. the predicted probability and observed proportion of complications among patients with the lowest risk of complications were 2.2% and 5.9% , respectively . the predicted probability and observed proportion of patients who experienced complications in the high - risk group were 38% and 13% , respectively ( p < 10 ) . thus , data obtained using a model developed to predict the frequency of complications among women with traditional wound closures suggest that using tc - coated suture material decreased src . we calculated sample size of a randomized trial to demonstrate the protective effect of tc - coated sutures . in the general population , the inclusion of 629 patients in each arm ( alpha = 5% , power = 80% ) would be necessary based on risks of scr of 13% and 8% in the control arm and tc - coated arm , respectively . by selecting only patients with a risk of scr more than 10% based on our model , the inclusion of only 55 patients in each arm is necessary ( alpha = 5% , power = 80% ) , based on risks of scr of 38% and 13% in the control arm and tc - coated arm , respectively . the primary objective of this prospective study was to evaluate the efficiency of an antibacterial - coated suture to decrease both ssi and other src ( such as skin necroses , delay to wound healing , or wound dehiscence ) after breast surgery . src rates were 13% and 8% , respectively , for group 1 and group 2 , which is consistent with most studies ( 0.845% ) [ 2931 ] . the observed complication rate for patients treated with tc - coated suture material seemed to be similar to that observed during the first study period ( table 2 ) and may be wrongly interpreted as unsatisfactory . however , based on patient and surgery characteristics , the complication rate was expected to be higher . this was shown through the use of a model that was based and validated on the classical population . in the present study , triclosan is a broad - spectrum antimicrobial agent present in various topical products , ( soaps , surgical scrubs , toothpaste  ) for over 30 years . it has antimicrobial activity against the most common organisms that cause ssi , including methicillin - resistant staphylococcus aureus ( mrsa ) , and methicillin - resistant staphylococcus epidermidis [ 10 , 13 ] . after resistance for pseudomonas aeruginosa was found in vitro , triclosan was suspected to induce resistance to antibiotic [ 33 , 34 ] . however , these results were not confirmed for other bacteria   or in vivo [ 36 , 37 ] . its efficiency in reducing the infection of surgical wounds has been reported in gynecological [ 23 , 24 ] and extragynecologic surgery ( neurosurgery , thoracic , and abdominal surgery ) [ 1719 ] . ford et al . showed that intraoperative handling of coated polyglactin 910 sutures was indistinguishable from that with triclosan . however , the advantages of tc - coated sutures were criticized in several randomized trials . in a few series , the use of tc - coated sutures failed to reduce the rate of wound infection after appendectomy or head and neck surgery . in a trial concerning breast reduction surgery , deliaert et al . reported a higher wound dehiscence rate with tc - coated sutures than with conventional sutures . it is important to note that the expected potential beneficial effects of tc - coated sutures extend beyond merely the prevention of infection . in 2007 , gmez - alonso et al . demonstrated the efficacy of these sutures in preventing bacterial colonization and modulating the inflammatory response , which allowed better tissue healing . the risk factors of suture - related complications found in our predictive model based on logistic regression are tumor multifocality , axillary lymphadenectomy , and age . comparing the effects of various suture materials in reducing ssi and poor wound healing in a randomized trial may require the inclusion of several hundred patients , because the prevalence of these complications is low . models may be a useful way to test a new treatment or therapeutic strategy without randomization . any difference between the predicted probability and the observed proportion reflects that the new treatment allocation or strategy modifies the outcome . of course , such a multivariate analysis can never adjust for unmeasured or unknown confounders . the superiority of a randomized study is not denied but may require inclusion of several hundred patients with selection criteria that limit its generalizability . we report in our study that selecting patients based on their baseline risk of scr may help to decrease the number of patients to include in a randomized study by a factor 10 . this is clearly a major advantage of our approach , which indeed prevents to unnecessarily include patients that will have no benefit of treatment because of their very low risk . the interest in a randomized trial is also driven by the additional cost of the new strategy . in our practice , we used six sutures : the involved cost was 2096 with tc - coated sutures , as compared to 1826 with classical sutures . olsen et al . found that the attributable cost of ssi after breast surgery was $ 4,091 . first , the number of cases was limited ( n = 190 ) so the interpretation of our results may lack statistical power . second , the robustness of our predictor model has been validated in the same population . notably , this was performed using a validated bootstrap method [ 3841 ] for a large group of patients and provides multivariate stratification for maximizing the accuracy of estimation that might be superior to simple matching , especially if it is based on more extensive information ( larger datasets ) . finally , the study was performed at a single center in france over two different time periods and using two different types of suture material . using the same periods at a year 's interval would prevent bias associated with season or residents . in conclusion , in this preliminary study , age , axillary lymphadenectomy , and multifocal tumor were the major predisposing factors leading to breast wound infection and suture - related complications . tc - coated sutures seem to reduce the rate of complications after the surgical treatment of breast pathologies , particularly in the high - risk group .
background . to reduce the incidence of microbial colonization of suture material , triclosan- ( tc-)coated suture materials have been developed . 
 the aim of this study was to assess the incidence of suture - related complications ( src ) in breast surgery with and without the use of tc - coated sutures . methods . 
 we performed a study on two consecutive periods : 92 patients underwent breast surgery with conventional sutures ( group 1 ) and 98 with tc - coated sutures ( group 2 ) . 
 we performed subgroups analyses and developed a model to predict src in group 1 and tested its clinical efficacy in group 2 using a nomogram - based approach . 
 results . 
 the src rates were 13% in group 1 and 8% in group 2 . 
 we found that some subgroups may benefit from tc - coated sutures . 
 the discrimination obtained from a logistic regression model developed in group 1 and based on multifocality , age and axillary lymphadenectomy was 0.88 ( 95% ci 0.770.95 ) ( p < 104 ) . 
 there was a significant difference in group 2 between predicted probabilities and observed percentages ( p < 105 ) . the predicted and observed proportions of complications in the high - risk group were 38% and 13% , respectively . conclusion . 
 this study used individual predictions of src and showed that using tc - coated suture may prevent src . 
 this was particularly significant in high - risk patients .