Prevalence of occult cochlear basal turn patency

Abstract

Background

Perilymph gusher (PLG) is a rare complication of otologic surgery attributed to a communication between the cochlea and the internal auditory canal (IAC). Subtle patency between the cochlear basal turn and IAC has recently been identified on computed tomography (CT) as a risk factor, specifically when the defect is > 0.75 mm.

Objectives

Investigate the prevalence of radiographic cochlear basal turn patency.

Materials and Methods

Patients with CT of the temporal bones and inner ears interpreted as “normal” were included. An otologist and a radiologist independently reviewed CTs to measure radiographic dehiscence in an oblique plane along the interface of the cochlea and IAC. Known PLGs were excluded.

Results

Two hundred and ten ears were included (88 conductive or mixed hearing loss, 62 sensorineural hearing loss, 41 audiometrically normal ears). 71 ears (33.8%) were radiographically patent. Mean defect width was 0.41 mm (0.15-0.7 mm). Defect width was not associated with type of hearing loss, age, or gender. No defects were wider than 0.75 mm.

Conclusions

Radiographic patency of the cochlear basal turn may be present in patients with hearing loss and normal hearing, but patency > 0.75 mm (i.e. risk for PLG) is rare.

Chinese abstract

背景：外周淋巴液喷流（PLG）是耳科手术的一种罕见并发症, 起因于耳蜗和内耳道（IAC）之间的连通。人工耳蜗基底转弯和IAC之间的细微连通最近已通过计算机断层扫描（CT）将其确定为危险因素, 尤其是当缺口> 0.75 mm时。

目的：调查X线耳蜗基底部连通的患病率。

材料和方法：该研究包括颞骨和内耳CT解释为“正常”的患者。耳科医生和放射科医生独立检查了CT, 以测量沿耳蜗和IAC界面在倾斜平面上的放射开裂。已知的PLG被排除在外。

结果：包括210只耳朵（88例传导性或混合性听力损失, 62例感性神经性听力损失, 41例听力正常）。71耳（33.8％）射线图显示连通。平均缺口宽度为0.41毫米（0.15-0.7毫米）。缺口宽度与听力损失类型、年龄或性别无关。缺口宽度不超过0.75毫米。

结论：听力障碍患者和听力正常患者可能存在耳蜗基底转角的射线连通, 但连通度大于0.75毫米（即PLG风险）的情况很少。

Keywords:

• Perilymph Gusher
• inner ear deformity
• temporal bone imaging
• cochlear implant
• stapedotomy

Disclosure statement

The authors report no conflict of interest.