Extended Inferior Turbinate Flap for Endoscopic Skull Base Reconstruction

Background/Objective: The endoscopic endonasal approach )EEA) has been a key advance in the treatment of skull base lesions. Postoperatively, large dural defects can pose a significant risk of cerebrospinal fluid (CSF) leak. The nasoseptal flap has served as the primary reconstructive option due to its size and versatility. When its use has been precluded by prior surgery or tumor involvement of the nasal septum, the posterior pedicle inferior turbinate flap (ITF) is a viable option for small midclival defects. Limitations of the ITF include its small surface area and limited arc of rotation. We describe a novel extended inferior turbinate flap (EITF) that expands the reconstructive applications of this flap.

Study Design: Cadaveric anatomical study.

Methods: The EITF was designed for harvest in cadaveric specimens based on the inferior turbinate (IT) artery, a terminal branch of the sphenopalatine artery (SPA). The anatomical limits of the EITF were as follows: posteriorly, the IT mucoperiosteum pedicled on the IT artery; superolaterally, the mucoperiosteum along the superior attachment of the IT to the lateral nasal wall; anteriorly, from the head of the IT to the junction of the nasal floor with the septum; inferomedially, the junction of the nasal floor and septum. Moreover, this EITF can be further expanded to include septal mucosa, if available. Measurements of the length, width, and surface area were recorded. The arc of rotation and reach for reconstruction of ventral skull base defects were assessed in the cadaver.

Results: The average width of the flap, defined as the widest measurement at the anterior margin of the flap, was 5.46 ± 0.58 cm (7.32 ± 0.59 cm with septal mucosa). The average length of the flap, defined as the longest measurement at the lateral margin of the flap, was 5.01 ± 0.58 cm (5.28 ± 0.37 cm with septal mucosa). The average surface area of the flap was 27.26 ± 3.65 cm² (40.53 ± 6.45 cm² with septal mucosa). The flap was rotated with the turbinate surface at the inferior aspect of the clival defect, and the extended mucosa of the floor was able to cover the upper portion of the clival defect. Thus, the angle of rotation was smaller when compared with the 180-degree angle necessary for the traditional ITF to reach the clivus. The EITF was sufficient to cover defects extending between the paraclival internal carotid arteries.

Conclusion: The EITF presents an additional option for reconstruction of skull base defects when the nasoseptal flap is unavailable or fails. In contrast to the traditionally described ITF, the EITF provides a greater surface area and better arc of rotation.