Kobayashi T, Toshima M, Yaginuma Y, Ishidoya M, Suetake M, Takasaka T
Department of Otolaryngology, Tohoku University School of Medicine, Sendai, Japan.
Am J Otol. 1994 Sep;15(5):658-62.
It is hypothesized that blockade of the tympanic isthmus causes isolation of the attic and the adjacent middle ear spaces and that subsequent building up of the negative pressure in these spaces results in retraction of the pars flaccida, leading to formation of attic retraction pockets and cholesteatomas. To examine this theory, computerized tomographic (CT) findings of these conditions were evaluated in a series of 53 ears with retractions of the pars flaccida (attic retractions of Tos type II or deeper), including both retraction pockets and cholesteatomas. In 26 of 28 ears with attic retraction pockets, at least a portion of attic was aerated, and in 22 of these 26 ears, the mastoid antrum was also aerated. In contrast, in the 25 cases with attic cholesteatomas, these numbers decreased to 10 and 5, respectively, and the lack of aeration of the attic was demonstrated in 15 of 25 (60%) of the cases. In three cases of cholesteatoma, follow-up CT revealed either growth of a cholesteatoma from a retraction pocket or development of a small cholesteatoma into a large one. In these ears it was seen that the well-pneumatized attic and mastoid antrum seen in the initial CT was depleted by the growth of cholesteatoma that took place over a period of 4 months to 2 years. These results, showing good patency of the aditus and a pneumatized antrum in early stages of most cases of retraction pockets and cholesteatomas, are not in agreement with the hypothesis that the blockade of the tympanic isthmus is responsible for the pathogenesis of retraction pockets and cholesteatomas originating in the pars flaccida.
据推测,鼓室峡部阻塞会导致上鼓室及相邻中耳腔隔离,随后这些腔隙内负压增加会导致松弛部回缩,进而形成上鼓室回缩袋和胆脂瘤。为验证该理论,对53例松弛部回缩(Tos II型或更深的上鼓室回缩)患者的耳部进行了计算机断层扫描(CT)检查,包括回缩袋和胆脂瘤。在28例有上鼓室回缩袋的耳朵中,26例至少部分上鼓室有气房,其中22例乳突窦也有气房。相比之下,在25例上鼓室胆脂瘤患者中,这两个数字分别降至10例和5例,25例中有15例(60%)显示上鼓室无气房。在3例胆脂瘤患者中,随访CT显示胆脂瘤从回缩袋生长或小胆脂瘤发展为大胆脂瘤。在这些耳朵中可以看到,最初CT显示的气房良好的上鼓室和乳突窦在4个月至2年的时间里因胆脂瘤生长而消失。这些结果表明,大多数回缩袋和胆脂瘤早期病例的鼓窦入口通畅且乳突窦有气房,这与鼓室峡部阻塞是起源于松弛部的回缩袋和胆脂瘤发病机制的假说不一致。