術後性上顎嚢胞術式の考察（第2報）

Surgical Approaches for Postoperative Cysts of Maxilla (2)

はじめに

　術後性上顎嚢胞の手術法では上顎洞根本手術が一般に行われてきたが，画像診断の進歩により術後性上顎嚢胞がより精密に把握できるようになって，経鼻的手術も行われるようになった。本疾患の術式には定説はないが，本疾患がすでに術後性であることや好発年齢を考えると，再発を防ぐことは第一の課題である。今回は術後性上顎嚢胞のX線CT画像を検討し，嚢胞の性状による鼻内開窓術（下鼻道側壁）の適応について検討する。

74 cases (79 sides) of surgically confirmed post-operative cysts of the maxilla were reviewed and preoperative CT findings were analyzed. Of 79 sides, 74 cases underwent Caldwell-Luc operations and the remaining 5, endonasal window opera-tions at the inferior meatus.

Indications for the window operation are as follows:

1) monocystic or single cyst, 2) the cyst is in a close contact with the lateral wall of the inferior meatus, 3) seemingly incomplete septum in the cyst should be excluded.

Of 79 sides, 16 sides fulfilled the above conditions.

Surgical indices, such as distance from the nares to the lateral wall of the inferior meatal wall, angle between the sagittal midline plane and the line defined by the above distance, are measured by axial CT images by non-operated cases (50 cases), postoperative but non-cystic cases (40 cases) and postoperative cysts (49 cases) with retracted lateral walls of the inferior nasal meatus and 25 cases with bulges at the lateral walls by the cysts. Although cystic cases with bulge offer seemingly easy access by endonasal approach, the surgical indices are similar to the non-operated cases. In other words, the endonasal window operation is equally difficult both in non-postoperative and postoperative cases.