背景:鼓室后的解剖结构是高度可变的,手术进入是具有挑战性的。在内侧鼓室后,发现了一系列下降的凹陷:鼓室后窦,鼓室窦(ST),和鼓室下窦(STS)。大多数先前的ST解剖学研究将其评估为可变宽度和深度的单个凹陷,没有凹陷,只是在轴向截面。
方法:在100例病例中,在所有解剖平面上对ST进行双侧评估。定义并计数了两种矢状解剖类型的ST:0型(囊状ST),ST后下隐窝(PIR)缺失,和类型1,ST与PIR(碗形ST)。
结果:在200面,发现了144个0型ST(72%)和56个1型ST(PIRs)(28%)。在右侧/左侧,在74%/70%中发现了0型ST,在PIR中发现了1型ST,26%/30%。性别与两侧ST类型之间没有显着相关性。在一般地段,双侧对称的0型占68%,24%的双边对称类型1,双边不对称组合0+1仅为8%。
结论:ST的PIR不是鼓室后的罕见解剖变异。它隐藏在ST深处,难以通过中耳进入。它还可以保留残留的胆脂瘤。如果没有其他解剖学限制,面后入路可以进入ST的PIR。
BACKGROUND: The anatomy of the retrotympanum is highly variable, and surgical access is challenging. In the medial retrotympanum, a descending series of recesses are found: the posterior tympanic sinus, the sinus tympani (ST), and the subtympanic sinus (STS). Most of the previous anatomical studies of the ST evaluated it as a single depression of variable width and depth, without recesses, just on axial sections.
METHODS: The ST was evaluated bilaterally in all the anatomical planes on a lot of 100 cases. Two sagittal anatomical types of the ST were defined and counted: type 0 (saccular ST), with absent postero-inferior recess (PIR) of the ST, and type 1, ST with PIR (bowl-shaped ST).
RESULTS: In 200 sides, 144 type 0 ST (72%) and 56 types 1 (PIRs) of the ST were found (28%). On the right/left sides the type 0 ST was found in 74%/70% and the type 1, with PIR, in 26%/30%. There were no significant correlations between sex and the ST types on both sides. In the general lot, bilaterally symmetrical types 0 were found in 68%, bilaterally symmetrical types 1 in 24%, and the bilaterally asymmetrical combination 0+1 in just 8%.
CONCLUSIONS: The PIR of the ST is not a scarce anatomical variation in the retrotympanum. It is hidden deep to the ST and difficult to access through the middle ear. It also could retain residual cholesteatoma. A retrofacial approach could access the PIR of the ST if no other anatomical limitations occur.