Establishment Of A Model For Predicting The Postoperative Morbidity In The Patients With The Pelvic And Acetabulum Fractures

Clinical medicine is developing a quantitative explain-type from empirical describe-type.The objective evaluating risk of operation is a new topic for clinical research.The assessment of operative risk mainly depended on the patient's clinical symptom,signs,physiological parameter's,operative severity,and so on.Acute Physiology And Chronic Health Evaluation(APACHE1) was developed in 1981 by Kuaus et al,who spended 3 years for bolting 34 APS index from mass data,in addition to CPS before disease.APACHEII,Ⅲwere developed in 1985,1989, respectively.It was mainly applied estimation of prognosis and evaluating quality of remedy,including severe cases of surgical postoperation.A standardized method of assessment of operative prognosis,The Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity(POSSUM) was produced in 1991 by Copeland et al,which had been used in general surgery,thoracic surgery,vascular surgery etc.Copeland et al applied the modified POSSUM scoring system for risk of orthopedics in 2002.They were derived from England originally and 200,000 patients. It needs to be tested whether they refer to operative patients of China.Since we have not Chinese operative patients database and predictive model.Location of pelvis and acetabulum are deep,anatomies are complex.Pelvic and acetabular fractures are mostly caused by high-energy injuries,which are crash,great shifting and difficult reducing.There are thick soft tissues in the fracture site,more hemorrhages,great trauma in operating,thus dispute in choosing treatment. Previously,the expectant treatment of traction had not achieved anatomical reestablishment and good joint function for advanced stage.Since 10 years,the fractures have been gradually developed operative treatment following improvement of understanding.Firstly,the life-threatening associated injuries are treated,vital signs are equability,physiologic derangements are corrected,and then the fractures are reduced and fixed.Consequently,mortality is low,but morbidity is high.It is more important to evaluate operative risk of the pelvic and acetabular fractures and predict morbidity.Objective:1.To research characteristic of operative complication of the pelvic and acetabular fractures.2.Establishment of a model for predicting the postoperative morbidity in patients with pelvic and acetabular fractures base on POSSUM system.3.To test predictive capability for model of the sample,assess risk of operation and evaluate operative quality,were to easure operative safety and offer satisfactory therapeutic decision-making.Patients and Methods:1.The clinical of 94 patients with pelvic and acetabular fractures were retrospectively reviewed for analysis of the postoperative complications and in-hospital from January 1997 to May 2007 in NanFang Hospital.2.The preoperative physiological scores(PS) and operative severity scores(OS) of the patients were selected as the variables,PS was a 12-factor,four-grade,as same as POSSUM system.OS was modified by orthopedics and specialty of pelvic and acetabular fractures.Replaced the peritoneum infection with operative approach. Replaced the several operations at one time with operative duration.Replaced the cancer with ISS.The size and type of operation were made into grades according orthopedics specialty.Each of the factors was scored exponentially as 1,2,4 or 8.3.To constitute the standard for entering cases(referring correlated standards).4.To collect data(all data come from the operative doctor record).5.To deal with data(all data must be coded again according to standard).6.PS and OS as covariates,complication as dependent,and their regression coefficients were calculated by logistic regession analysis to establish the model for predicting the postoperative morbidities.The predictive value of the model was evaluated according to the ROC curve(receiver operator charcteristic curve).7.Morbidities were calculated by POSSUM equation.(make use of medicial software,JING Xue-chen《YI DIAN TONG》in 97 hospital of PLA).The predictive value was tested by the ROC curve.Estimated index:sensitivity,specificity, concordance rate,positive predictive value(PV+),negative predictive value(PV_), misclassification rate,omission classification rate,area under ROC curve.Result:1.94 patients with pelvic and acetabular fractures had been operated in this study,including male 73 case,female 21case,mean age 35.6 years,postoperative complications 38 cases,non- complications 56 cases.The 94 patients suffered associated injuries that involved all over the body.Accoding to AIS 2005,48 cases had associated trauma in 1 region,15 cases had 2 regions associated trauma,6had 3, 2 had 4;also there is 1 patient who suffered associated trauma in 5 regions.2.The complications group(38cases) compared with the non- complications group(56cases),PS and age were tested by t-test,OS and ISS were tested by Wilcoxon rank sum test,the mean age was no significiant difference(34.50±12.05VS36.32±11.05)(P＞0.05),the mean PS,OS and ISS were significiant difference (17.26±2.84VS16.04±2.77,19.50±5.14VS13.00±3.81,15.60±7.45VS13.78±7.85)(P＜0.05), the former was higher than the latter.3.The model for predicting the postoperative morbidity in the patients with fractures of the pelvis and acetabulum was established by the sample in this study:ln P/(1-P) =-8.430+ 0.182×PS+0.316×OS.Its area of ROC curve 0.888,cut point P=37%,sensitivity 84.21%,specificity 82.14%,coincident degree82.98%,its misclassification15.79%and omission classification rate 17.86%.Conclusion:1.PS and OS have significant effect for postoperative morbidity.The higher the scores,the higher is morbidity.2.The model of the sample is better than POSSUM equation for predicting postoperative morbidity with patients of pelvic and acetabulum fractures.Sen,Spe, concordance rate,area under ROC curve increase,misclassification rate,omission classification rate reduce.It is possible to fit Chinese all the more.3.This model may be used to determine the treatment project.Before operation, the scores is higher than cut-off point,we could improve the patients' physiological health firstyly,and then scored again several later.During the operation,we can perform micro-injury procedures to shorten the operative time and decrease the blood loss.It is helpful for ensuring operative safety and clinical therapeutic decision-making.