[Radioanatomic study on the role of Hadad-Bassagasteguy flap in skull base reconstruction in endoscopic endonasal approach].

Objective: To evaluate the value of Hadad-Bassagasteguy flap (HBF) in endoscopic endonasal approaches (EEA) skull base reconstruction by radioanatomic measurements on CT of the skull base of Chinese adults. The following data in terms of anterior skull base defect and reconstruction, sphenoid platform area and middle skull base defect and reconstruction including sphenoid platform and sella area, clivus area defect and reconstruction, and HBF were collected and assessed. Methods: CT image data of 42 Chinese adults were selected to obtain radioanatomic measurement data related to HBF, anterior skull base defect and reconstruction, middle skull base defect and reconstruction, and defect and reconstruction of clivus area. SPSS 26.0 software was used to analyze the data. Results: The radioanatomic measurement data about HBF and skull base of 42 Chinese adults were obtained. The width of the leading edge of HBF [(37.49±2.86) mm] was 6 mm more than the anterior skull base width at the level of the anterior ethmoidal artery [(30.87±8.61) mm], and the width of the trailing edge of HBF [(42.61±3.95) mm] was also 6 mm more than the anterior skull base width at the level of the sphenoethmoidal junction [(26.79±2.79) mm]. The total length of HBF including the pedicle [(79.68±4.96) mm] was 6 mm more than the length of the anterior skull base reconstruction [(54.06±8.67) mm], and the length of HBF without pedicle [(46.27±3.14)] mm was 6 mm more than the length of anterior skull base defect [(30.87±8.61) mm]. The trailing edge width was 6 mm more than the planum sphenoidal width at the level of the optic strut [(30.87±8.61) mm]. The total length of HBF including the pedicle was 6 mm more than the length of the planum sphenoidal, and the sella reconstruction [(64.44±10.25) mm], also was 6 mm more than the length of the planum sphenoidal reconstruction [(73.61±8.28) mm]. The length of HBF without pedicle was 6 mm more than the length of the planum sphenoidal, and the sella defect [(27.88±3.74) mm], also was 6 mm more than the length of the planum sphenoidal defect [(15.50±3.38) mm]. The width of the leading edge of HBF and the width of the trailing edge were both 6 mm more than the width of clivus reconstruction at the level of the foramen lacerum [(21.68±2.30) mm]. The total length of HBF including pedicles was 6 mm more than the clivus reconstruction length [(67.09±5.44) mm], while the length of HBF without pedicles was also 6 mm more than the clivus defect length [(37.19±3.80) mm]. Conclusions: In this study, the radiosanatomic measurements ensured that HBF could provide sufficient tissue flap for the reconstruction of the anterior skull base and sphenoid plateau and extend the reconstruction area to sella and clivus. Preoperative radiosanatomic measurement can be used to predict the size of HBF required for skull base reconstruction, which provides important guidance for flap harvest.