The different concepts of surgical managements between anterior and lateral skull base reconstructions based on surgical purposes

Abstract

Objective: Anterior and middle cranial fossa defects require different strategies, depending on their anatomical location. The aim of this study was to elucidate the surgical managements for the defects based on surgical purposes and to clarify the conceptional differences relating to anterior and lateral skull base reconstructions.

Methods: This study included patients who had undergone reconstructive surgery for anterior or middle cranial fossa defects in our institution between July 2008 and June 2019. It consisted of 66 patients who had been subject to anterior skull base reconstructions, and 84 patients who had experienced lateral skull base reconstructions. The medical records were examined retrospectively, and the surgical purposes and procedures performed were reviewed. The surgical purposes were divided into four groups: Separation, Restoration, Augmentation, and Coverage.

Results: Regarding anterior skull base reconstructions, the Separation group included 65 patients, who represented 98% of this category. There were 26 cases in the Separation-only group, 20 of which were reconstructed with locoregional flaps, and 6 of which with free tissue transfers. A Combination group, which consisted of Separation and Other purposes, consisted of 40 cases. Within this group, 5 cases were reconstructed with locoregional flaps, and 35 with free tissue transfers. Regarding lateral skull base reconstructions, the Separation group included 34 patients, who represented 40% of this category. The rate of the Other purposes represented the majority. In the Separation-only group of 24 patients, 16 cases were reconstructed with locoregional flaps and 8 cases with free tissue transfers. In the Combination group of 10 patients, 2 cases were reconstructed with locoregional flaps and 8 cases with free tissue transfers. In groups other than the Separation group, 27 cases were reconstructed with locoregional flaps and 23 cases with free tissue transfers.

Conclusion: In most anterior cranial fossa defect cases, the surgical purpose is separation. In middle cranial fossa defect cases, there are many cases in which the surgical purpose is not separation. In the Separation groups, relating to both anterior and lateral skull base reconstructions, the use of locoregional flaps was an effective measure. Free tissue transfers were required in many cases of the Combination group. Outside of the Separation group associated with lateral skull base reconstructions, the use of locoregional flaps and free tissue transfers were almost equal in proportion, and the selection of reconstructive procedures tended to change from locoregional flaps to large free flaps with increase in the numbers of surgical purposes.

Keywords: Anatomical location; Anterior skull base reconstruction; Lateral skull base reconstruction; Reconstruction concept; Surgical management; Surgical purpose.