鼻中隔延長術とstrut再建—男性と女性の違いを含めて—

Septal Extension Graft and Strut Reconstruction in Rhinoplasty

はじめに

　外鼻形成術において鼻尖位置の決定にはさまざまな術式が考案されてきたが，なかでも鼻中隔延長術 1）～3）とcolumellar strut graft 4）は外鼻骨格を構造的に補強する術式であり中心的役割を担っている。オープンアプローチによる外鼻形成術は外鼻骨格の構造をいったん分解し，再度組み立てる手術操作である。この過程で鼻尖位置は変化しないと思われるが，実際には術後の腫脹や皮膚の緊張，表情筋の外力によって経時的な変化が起こり得る。さらにもともとの鼻中隔軟骨や鼻翼軟骨（lower lateral cartilage：以下，LLC）の構造強度に依存する術式であるため，患者個別に，あるいは男女の性差によって，軟骨強度，軟部組織の重さ・厚さが異なるなど不確定要素が多い。

　本稿では鼻中隔軟骨の強度の弱い症例，鼻中隔軟骨の上弯・前弯への対応について述べる。

　The septal extension graft (SEG) is considered highly effective in terms of nasal tip elongation and the prevention of postoperative retraction. However, even with a stable procedure, it can be challenging to maintain the nasal morphology long-term due to the vulnerability of the septal cartilage, which provides structural strength. The vulnerability of the septal cartilage is influenced not only by the thickness of the cartilage and the presence and degree of cracks but also by the presence of caudal septal deviation, which significantly affects the skeletal strength. Cartilage exhibits maximum axial compression strength when it is straight, and a prerequisite for the success of the surgery is thus the absence of curvature in the septal cartilage. The treatment of caudal septal deviation requires the adjustment of the length of caudal septum; correction alone with a batten graft does not provide long-term stability. In this paper we discuss techniques for correcting caudal septal deviation and for performing nasal tip elongation surgery via autologous cartilage transplantation to achieve nasal tip elongation by an SEG. Postoperative changes in nasal tip projection and rotation are reported to be likely in males, and the use of an SEG when nasal tip elongation is performed in males is preferable to a columellar strut as it provides a more robust support.