Application Of Computed Tomography Angiography Mapping After Perforator Locating By Color Doppler Ultrasound For Preoperative Predesign Of Chimeric Anterolateral Thigh Perforator Flap In Head And Neck Reconstruction

Background: The anterolateral thigh flap(ALTF)is the workhorse flap for repairing soft tissue defects of oral and maxillofacial head and neck region.The blood supply of this flap is mainly derived from the cutaneous perforator of the descending branch of the lateral femoral circumflex artery.Due to the fact that one perforator can supply a large volume of skin paddle,a single ALTF only needs to carry one perforator for blood supply.Clinically,we can design and prepare an ALTF carrying two or more perforators to form a chimeric flap or a double(multiple)paddle ALTF to reconstruct the complex soft defects of oral,maxillofacial head and neck region.Due to the variation in the cutaneous perforators of each branch of the lateral femoral circumflex artery,there may be only one perforator in the flap harvesting area;or even if two skin perforators exit,but may not derive from a common artery,therefore the chimeric perforator flap or double(multiple)paddle flap cannot be raised as expected.Under the circumstances,it is necessary to explore the contralateral thigh or to anastomose two sets of blood vessels,which will increase the patient’s secondary injury or prolong the operation time.Objective: The purpose of this study was to integrate the preoperative Color Doppler Ultrasound(CDU)and Computed Tomography Angiography(CTA)data of patients,who have oral cancer requiring surgical treatment and subsequent reconstruction with ALTF,to analyze the cutaneous perforators of lateral femoral circumflex artery,including the incidence,distribution,and artery origin of the perforators.For cases that required chimeric ALTF or double/multiple paddle ALTF flap to repair,the combined CDU and CTA data was used to clear-cut the numbers and location of cutaneous perforators preoperatively,aiming to assist in harvesting the chimeric ALTF to repair the complex soft tissue defects.Methods: From June 2018 to January 2021,patients with oral malignancies requiring extensive surgical resection and subsequent repair with ALTF were enrolled.First,CDU was performed to determine the cutaneous perforator of the lateral femoral circumflex artery,and perforators were marked with metal markers on the skin where they passed through the deep fascia.Second,through CTA scanning,the perforator markers determined by CDU were integrated into CTA data,and then the generated medical Digital Imaging and Communication in Medicine(DICOM)were imported into Mimics 21.0 software to establish a threedimensional model of skin,blood vessels and bone.The number,type and course were analyzed,in addition,by establishing coordinates,the localization of the cutaneous perforator on the skin of thigh was justified.For patients who need to raise chimeric flaps,the above method of integrating CDU and CTA was utilized to analyze the features of perforating vessels and the cutaneous perforator localization on the thigh was calibrated based on the integrated CUD and CTA data.Then the chimeric ALTF was harvested according to the preoperative predesign.Result: 1.Compared with CTA,CDU can increase the detection rate of cutaneous perforators and the selectivity of chimeric ALTF raising;2.Be superior to CDU,CTA can determine whether the perforators originate from the same source vessel;3.The integration of CDU and CTA can assist in calibrating the precise localization of cutaneous perforators on the skin of the thigh;4.In 3 patients,through the combined application of CDU and CTA,two or more skin perforators were successfully identified and harvested,and the complex soft tissue defects were successfully repaired by the chimeric ALTF.Conclusions: Application of CTA mapping after perforator locating by CDU for preoperative predesign of chimeric ALTF can achieve complementary advantages,increase the detection rate of perforator vessels,and accurately locate perforators.Assisted with Mimics software,personalized chimeric ALTF can be preoperatively designed according to the feature of the defect to assist in proper repair of the complex defects of head and neck.In addition,it provides a feasible option to reduce the time of flap raising,decrease surgical injury and simplify surgical process.