Abbas Maha, Wang Jing, Leboucq Nicolas, Mondain Michel, Blanc Fabian
Department of Otolaryngology and Head and Neck Surgery, Gui de Chauliac Hospital, CHRU Montpellier - Centre Hospitalier Régional Universitaire, Université de Montpellier, Montpellier, France.
Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM U1298, Montpellier, France.
J Assoc Res Otolaryngol. 2024 Dec;25(6):611-617. doi: 10.1007/s10162-024-00963-0. Epub 2024 Sep 18.
The cochlear aqueduct (CA) is a bony canal located at the base of the scala tympani of the cochlea. It connects the inner ear perilymph fluid to the cerebrospinal fluid of the posterior cerebral fossa. Its function is not well understood, as it seems to be patent in only a fraction of adult patients. Indirect observations argue in favor of the CA being more patent in children. To study the CA morphology in children, we performed a retrospective single-center study of 85 high-resolution temporal bone computed tomography (hrCT) scans of children with a mean age of 3.23 ± 3.07 years (13 days of life up to 18 years), and compared them with a group of 22 adult hrCT (mean age of 24.01 ± 3.58 years). The CA morphology measurements included its total length, its funnel (wider intracranial portion) length and width and its type (indicating its radiological patency), according to a previously published classification. The dimensions of the CA were significantly smaller in children compared with adults for the axial length (10.37 ± 2.58 versus 14.63 ± 2.40 mm, respectively, p < 0,001) and the funnel length (3.94 ± 1.59 versus 6.01 ± 1.77 mm, respectively, p < 0,001). The funnel width tended to be smaller but the difference was not significant: 3.49 ± 1,33 versus 3.89 ± 1.07 mm, p = 0,22. The repartition of types of CA was also statistically different. The CA appeared to be more identifiable in the children population. Type 1 (CA visible along its entire course) accounted for 42% (36/85) of children and only 5% (1/22) of adults, type 2 (visible in the medial two thirds) for 30% (25/85) versus 31% (7/22), type 3 (not visible completely along the medial two thirds) for 27% (23/85) versus 50% (11/22). Finally, type 4 (undetectable) was found in only 1% (1/85) of children and 14% (3/22) of adults (p < 0,001). Our study showed significant postnatal growth of the length of the CA, which was more rapid before the age of 2, and slowed after 6 years of age. Its width increased less, with children older than 2 years presenting a similar width to adults. The CA was more identifiable in hrCT in children, arguing for a more permeable tract. The number of completely ossified CA was significantly lower in the children population. These findings highlight the differences between the CA morphology in adults and children and raise the question of differences in function. Moreover, these differences may impact the pharmacodynamics of drugs or vectors delivered into the pediatric inner ear. Further studies are required, both on the anatomy of temporal bones and on the function of the CA in children.
蜗水管（CA）是位于耳蜗鼓阶底部的一个骨性管道。它将内耳外淋巴液与后颅窝的脑脊液相连。其功能尚未完全明确，因为在仅一小部分成年患者中它似乎是通畅的。间接观察结果表明儿童的蜗水管更通畅。为了研究儿童蜗水管的形态，我们对85例平均年龄为3.23±3.07岁（出生13天至18岁）儿童的颞骨高分辨率计算机断层扫描（hrCT）进行了一项回顾性单中心研究，并将其与一组22例成人hrCT（平均年龄24.01±3.58岁）进行比较。根据先前发表的分类，蜗水管形态测量包括其总长度、漏斗（颅内较宽部分）长度和宽度以及其类型（表明其放射学通畅情况）。与成人相比，儿童蜗水管的尺寸在轴长（分别为10.37±2.58与14.63±2.40毫米，p<0.001）和漏斗长度（分别为3.94±1.59与6.01±1.77毫米，p<0.001）方面显著更小。漏斗宽度趋于更小，但差异不显著：3.49±1.33与3.89±1.07毫米，p = 0.22。蜗水管类型的分布也存在统计学差异。在儿童群体中蜗水管似乎更易于识别。1型（在其整个行程中可见）在儿童中占42%（36/85），在成人中仅占5%（1/22），2型（在内侧三分之二可见）在儿童中占30%（25/85），在成人中占31%（7/22），3型（在内侧三分之二未完全可见）在儿童中占27%（23/85），在成人中占50%（11/22）。最后，4型（不可检测）在儿童中仅占1%（1/85），在成人中占14%（3/22）（p<0.001）。我们的研究表明，蜗水管长度在出生后有显著增长，在2岁之前增长更快，6岁之后减缓。其宽度增加较少，2岁以上儿童的宽度与成人相似。在儿童的hrCT中蜗水管更易于识别，这表明其通道更具渗透性。在儿童群体中完全骨化的蜗水管数量显著更低。这些发现突出了成人和儿童蜗水管形态的差异，并提出了功能差异的问题。此外，这些差异可能会影响输送到小儿内耳的药物或载体的药效学。需要对颞骨解剖结构以及儿童蜗水管的功能进行进一步研究。
