Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
Otolaryngol Head Neck Surg. 2012 Aug;147(2):323-8. doi: 10.1177/0194599812442866. Epub 2012 Mar 30.
To report the prevalence of anatomic variants on computed tomography (CT) in congenital aural atresia (CAA) and external auditory canal stenosis (EACS). Anatomic variants included inferiorly displaced/obstructing tegmen mastoideum, malleus-incus complex (MIC) directly lateral to stapes, facial nerve obstruction of oval window (OW) or middle ear, and incudostapedial joint (ISJ) angle.
Cross-sectional study.
Tertiary care children's hospital.
An anatomic analysis of 130 CT scans (98 children, 32 bilateral) of CAA/EACS, performed by a blinded neuroradiologist. Both Jahrsdoerfer's and new/modified anatomic considerations were graded in 32 atresiaplasty and 66 nonsurgical patients. Surgical data were analyzed for anatomic correlations related to surgical findings.
Prevalence of anatomic variants was as follows: 13% of the ears had mild inferior displacement of tegmen, 4% had a significantly obstructing tegmen, and 24% had MIC directly lateral to stapes. The facial nerve obstructed access to OW in 41% and middle ear in 21%. Six atresiaplasty patients were reported to have a large MIC obstructing stapes access with increased intraoperative difficulty in viewing and assessing the integrity and mobility of the ISJ and stapes. Five of these 6 (83%) were noted on CT scan. The mean ISJ angle was 101° (range, 51°-155°).
A large obstructing MIC increases difficulty of atresiaplasty. Awareness of the presence of these anatomic variants is an aid in teaching temporal bone anatomy and may possibly influence the decision regarding atresiaplasty.
报告先天性耳闭锁（CAA）和外耳道狭窄（EACS）患者 CT 扫描中解剖变异的发生率。解剖变异包括：鼓室盖低位/阻塞、镫骨肌-砧骨复合体（MIC）直接位于镫骨外侧、面神经阻塞卵圆窗（OW）或中耳、砧镫关节（ISJ）角。
横断面研究。
三级儿童保健医院。
由一名神经放射科医生对 130 例 CAA/EACS 患者的 CT 扫描（98 例患者，32 例双侧）进行解剖分析。在 32 例鼓室成形术和 66 例非手术患者中，对 Jahrsdoerfer 分类和新/改良解剖分类进行分级。对手术数据进行分析，以确定与手术发现相关的解剖相关性。
解剖变异的发生率如下：13%的耳朵鼓室盖轻度低位，4%的鼓室盖明显阻塞，24%的 MIC 直接位于镫骨外侧。面神经阻塞 OW 进入 41%，阻塞中耳进入 21%。6 例鼓室成形术患者报告存在大的 MIC 阻塞镫骨，导致术中观察和评估 ISJ 和镫骨的完整性和活动性的难度增加。这 6 例中有 5 例（83%）在 CT 扫描中发现。ISJ 角的平均角度为 101°（范围，51°-155°）。
大的 MIC 阻塞增加了鼓室成形术的难度。了解这些解剖变异的存在有助于教授颞骨解剖学知识，并且可能会影响鼓室成形术的决策。
