Retrospective Study On Risk Factors Of Vascularized Free Flaps And Establishment Of An Analysis System

Purpose:Microsurgical repair and reconstructoon is a powerful method to treat complex craniomaxillofacial defects.In recent ten years,vascularized free skin flaps have become more and more popular in repairing oral and maxillofacial defects.The application of various musculocutaneous flaps and osteomyocutaneous flaps and the development of microsurgical technology make the oral and maxillofacial reconstruction surgery more functional and personalized.However,necrosis after skin flap surgery often leads to reoperation,prolonged hospitalization period and higher hospitalization costs.In the early stage of microsurgery,the failure rate of skin flaps was as high as 20%,even higher in underdeveloped countries and regions.With the development of technology and equipment,the failure rate of skin flaps has gradually declined.The success rate of skin flaps reported by the most powerful maxillofacial surgery medical centers in developed European and American countries are between 98%and 90%.Microsurgery requires more technology and patients' own conditions than ordinary surgery,because it has higher risk of failure and more subsequent medical disputes,including huge trauma in donor area,secondary repair in recipient area and long-term wound treatment after operation.In conclusion,the cost of failure of vascularized free flaps is high for both doctors and patients.Therefore,it is very important to study and understand which factors will lead to the increase of the failure rate of skin flaps,and which surgical operations and coping measures can reduce the occurrence of failure of skin flaps.From the perspective of treatment time,such factors can be divided into preoperative factors,intraoperative factors and postoperative factors.From the point of view of both doctors and patients,it can be divided into objective factors of patients'own constitution and subjective factors of doctors' medical treatment.The preoperative risk factors are mainly the patient's own general condition,that is to say,these factors are established facts,such as obesity,smoking,diabetes,hypertension and so on,which are objective factors that doctors cannot change.In addition,the choice of the type of skin flap made by the doctor is also determined before the operation.It may change with the understanding of different doctors.Therefore,the choice of the type of skin flap is the subjective factor of the doctor.Intraoperative factors are mainly the factors that influence the survival rate of skin flaps during the operation,such as the choice of blood vessels in the affected area,the choice of anastomotic tools,the length of operation time,etc.These are also subjective factors.Postoperative risk factors are rarely reported,because the risk management industry for microsurgery patients has long reached a consensus.Postoperative head placement,the use of vasoactive drugs and drainage in the surgical area are conducive to the survival of the skin flaps.Why should this study first classify and classify these risk factors?Because many previous studies have misunderstandings,there are possible interference and confusion between subjective factors during the operation.Univariate regression analysis is inaccurate,which may lead to deviations in data statistics.Firstly,we analyze and classify various risk factors,which is helpful for our data statistical analysis.We should not only evaluate the preoperative systemic factors,but also understand the control of intraoperative risk factors and the choice of beneficial factors.All these need further study.To achieve this goal,we reviewed the clinical data of 297 free flaps from March 2013 to February 2019.Based on the data analysis of 297 patients' risk factors and surgical results,some high-risk factors for the failure of skin flaps and the factors promoting the success of skin flaps were screened out.In this way,we can optimize the surgical choice of patients,effectively intervene in risk factors,and reduce the risk of skin flap failure.Methods:1.Preoperative systemic factors including age,obesity(BMI index),diabetes mellitus,hypertension,smoking and type selection of skin flaps in 297 patients were analyzed retrospectively.The clinical data were recorded in detail,and the correlation between these preoperative factors and the survival rate of skin flaps was calculated by SPSS chi-square test and multivariate logistic regression analysis.2.A retrospective control study was conducted to investigate the effect of preoperative neoadjuvant chemotherapy on vascularized skin flaps.Of 297 patients,26 received neoadjuvant chemotherapy from July 2017 to February 2019.Thirty-four patients without neoadjuvant chemotherapy in the same period were taken as the control group.The influence of preoperative chemotherapy on the survival of skin flaps was calculated by SPSS software quadruple table chi-square test.3.We retrospectively study the risk assessment of subjective clinical factors of surgeons,including the use of venous micro-staplers,the selection of recipient vessels,and the use of anastomotic vasodilators during operation.Chi-square test and multivariate logistic regression were used to analyze the correlation between subjective factors and survival rate of 297 free flaps.Because the choice of the type of skin flap is closely related to the intraoperative factors and belongs to subjective factors,there are confounding factors among them,so the type of skin flap is also included in the multivariate regression curve analysis.Results:1.The preoperative clinical data of 297 patients undergoing free flap repair were analyzed retrospectively,including 221 males and 76 females.The oldest was 79 years old and the youngest was 12 years old,with an average age of 53.56 years.Distribution of disease sites in patients:Cheek 72 cases(23.99%),gingiva 45 cases(15.20%),jaw 57 cases(19.26%),tongue 77 cases(26.01%),floor of mouth 21 cases(7.09%),palate 13 cases(4.39%),pharynx 2 cases(0.68%),lip 5 cases(1.69%),facial skin 3 cases(1.01%)and parotid gland 2 cases(0.68%).All patients were not treated with radiotherapy before operation.Preoperative statistical analysis of risk factors yielded the following results.The results of single factor chi-square test:the types of skin flaps were p=0.476;diabetes p<0.01;elderly patients p=0.729;BMI index p=0.523;smoking history p=0.588;hypertension history p=0.854.The following data were obtained by multivariate logistic regression analysis:The types of skin flaps were p=0.254;diabetes p<0.01;elderly patient p=0.362;BMI index p=0.768;smoking history p=0.834;hypertension history p=0.732.2.A comparative study of patients undergoing vascularized skin flap surgery after neoadjuvant chemotherapy.One case of skin flap necrosis occurred in 26 patients after chemotherapy,the survival rate was 96.15%.Four cases of skin flap necrosis occurred in 34 patients without chemotherapy,the survival rate was 88.24%.The results showed that the survival rate of skin flaps after neoadjuvant chemotherapy was higher than that of patients without chemotherapy.Chi-square test was performed with SPSS software(p=0.271).3.Operational records of 297 patients undergoing free flap repair were analyzed retrospectively.Among them,83 cases were anastomosed with Couple microvascular stapler,5 cases failed,the failure rate was 6.02%.The other 214 cases were sutured by hand under microscope,29 cases failed,the failure rate was 13.55%.Among the 68 patients with unconventional vascular anastomosis,17 failed,with a failure rate of 25.0%.Of the 229 patients selected for routine vascular anastomosis,17 had skin flap necrosis,with a failure rate of 7.42%.147 cases were treated with vasoactive drugs and 9 cases were necrosis of skin flaps.The failure rate was 6.12%.150 patients did not use vasoactive drugs,25 patients had skin flap necrosis,and the failure rate was 16.67%.Chi-square test showed that the choice of unconventional vascular anastomosis was a risk factor for skin flap necrosis(p<0.01).The use of vasoactive drugs can significantly reduce the failure rate of skin flaps(p=0.004).Finally,multivariate risk regression analysis confirmed that the choice of anastomotic vessels and the use of vasoactive drugs had a direct impact on the prognosis of free skin flaps.Conclusions:1.Diabetes mellitus is the only preoperative risk factor for vascularized free skin flaps.Through literature review,it is found that preoperative radiotherapy will greatly increase the difficulty of surgery.Most scholars believe that preoperative radiotherapy will increase the risk of skin flaps necrosis.Therefore,we believe that radiotherapy is also one of the preoperative risk factors.2.In this study,we systematically reviewed the differences of intraoperative procedures and found that microanastomosis with unconventional blood vessels would bring additional risks to the skin flaps,while intraoperative use of papaverine to dilate and anastomose the blood vessels could reduce the occurrence of necrosis of the skin flaps.The use of microvascular staplers does not bring a higher success rate of skin flaps than manual anastomosis,but it can reduce the operating time of surgeons.After consulting a large number of literatures,we found that fluid infusion>7L during operation was also an intraoperative risk factor for poor prognosis of skin flaps.3.According to the data analysis and literature review,different risk factors were comprehensively assessed,and a preliminary skin flap risk assessment system was established.