Application Of Digital Technology In Anterolateral Thigh Flap Vascular Anatomy And Reconstructing Wounds

Background:Anterolateral thigh(ALT)flap has many advantages and has been widely used to repair all kinds of the wounds.But with its multiple variation of vascular anatomy,it makes the operation risks uncertain.Over 30 years,various technologies have been widely applied in order to accurately locate the perforators before operations,grasp vascular anatomical information and precisely design ALT flap for the purpose of reducing the risk of operation,but there still exist some disadvantages.The accuracy detected by the hand-held Doppler ultrasound device has a high false positive and false negative rate in ALT flap perforator.Color Doppler ultrasound can not reflect parent artery anatomical information of the perforators,and its accuracy has large differences due to the operators' proficiency.There are many advantages of Computed tomography angiography(CTA).First,it can locate the perforators accurately.Second,it can fully show vascular anatomical information of ALT flap.Third,the results are objective and stable.But there are also some disadvantages,such as expensive cost,big side effects,complex hardware support kit,and the image clarity,all of which remain to be improved.At the same time,the method of locating perforator is not simple and clear.The visual effect by three-dimensional reconstruction is not ideal.It can not be used to accurately design flap and simulate the harvest of flaps.All of these are hard to overcome for CTA.In recent years,digital technology of CTA combined with Mimics software has been gradually used to study the vascular anatomy and preoperative design of other skin flap.The feasibility and the advantage of the technique have been reported.But this kind of research is not mature,and there is no more reports about the technique clinically applied in the study of the vascular anatomy in ALT flap preoperative design.Objective:1.To clearly show the 3D vascular anatomy of the ALT flap through digital technology of CTA combined with Mimics15.0 software.2.To accurately locate the perforators,design individual ALT flap,simulate the harvest of flap,and guide the operation through digital technology.Methods:1.From March 2014 to January 2016,21 patients who needed reconstructing wounds by ALT flap were admitted into our department.The locations of soft tissue defect were the foot and ankle in 9 cases,the hand in 6 cases,the leg in 2 cases,the forearm in 2 cases,the knee joint in 1 case,and the head and face in 1 case.All defects were associated with exposure of bone and tendon.2.CTA was carried out before operation.The CTA data was imported into Mimics15.0 software to select appropriate perforators and donor sites,reconstruct 3D visualization model of ALT flap,and measure the related data.After that,locate the perforators by coordinates,design the individual ALT flap,and simulate the harvest of flap.3.Based on the preoperative design to harvest ALT flap,confirm the preoperative perforators.Observe the vascular anatomy of ALT flap.Measure preoperative indicators while operation and complete the repair of the wounds.4.Statistics and analysis of relevant data are carried out by using SPSS20.0 software and Sigmpaplot12.0 software.Results:1.CTA combined with Mimics15.0 software completely reconstructed the vascular anatomy of ALT flap,precisely located the perforators by coordinates,and simulated the harvest of flap.2.Before operations,CTA data was imported into Mimics15.0 software.36 perforators(outside diameter?0.8mm)which supply ALT flap intended to be harvested were found in 21 thighs.They were also fully found during operations,with a 100% accuracy.Intraoperative findings showed that the source of the perforators was the same as that was found before operations.Apart from the 36 perforators,7 ones(outside diameter<0.8mm)were also found during the harvest of flaps.The perforators were divided into three types in this study,septocutaneous perforators(14.0%),musculocutaneous perforators(39.5%)and hybrid musculoseptocutaneous perforators(46.5%).3.After statistic analysis,36 perforators' abscissas as well as ordinates that were located before operations and found while operations showed no statistically significant differences.During operations,the maximum length of vascular pedicle that can be cut was from 8.2cm to 17.1cm,with an average length of 12.7±2.7cm.The parent artery's origin,distribution and categories of perforators shown before operation were entirely consistent with those observed in operation.4.All flaps were harvested based on the preoperative design,and repaired the wounds precisely.Meanwhile,all flaps survived well and all cases were followed up after operations.Among them,the flaps on 18 cases were in good shape,but 3 needed a second-stage defatted operation due to flap bulking.Conclusions:1.The 3D model reconstructed by digital technology in ALT flap can truly and totally present vascular anatomical information before operations.2.Digital technology of CTA combined with Mimics15.0 software can accurately locate the perforators and complete the individual design of ALT flap before operations.It can also guide the operations so as to reduce the risks.