3D analysis of cough-induced nystagmus in a patient with superior semicircular canal dehiscence

We report here about a case (female patient) with superior semicircular canal dehiscence (SSCD). This patient presented with pressure-induced rotatory vertigo when she coughed or strained at stool. Loud sounds or Valsalva maneuver did not evoke any sensation of vertigo and/or disequilibrium. By contrast, when she coughed, vertical-rotatory nystagmus was clearly induced. The 3D analysis of cough-induced nystagmus revealed that the rotation axes of the nystagmus were well aligned with the right superior semicircular canal. In conjunction with the temporal bone CT study, the pathological localization in the inner ear in this patient was confirmed to be in the right superior semicircular canal.     

上半规管裂综合征的诊断

目的探讨上半规管裂综合征的临床诊断学特点，提高对该病的认识。方法回顾性分析近期诊断的6例上半规管裂综合征患者，总结其临床症状、体征、听力学和影像学特点。结果6例患者中4例患耳表现为低频听力下降，声反射均能引出；1例合并有中耳炎表现为极重度感音神经性听力下降；另1例听力正常。2例次患者有明显的自声增强，不能耐受自己说话的声音。5例次患者有不同程度的眩晕，眩晕持续时间数小时不等，程度不一。2例次患者主诉不能耐受外界噪声。4例次患者利用强声能诱导眩晕。所有患者在强声刺激或增加中耳压力、捏鼻鼓气时能观察到慢相向健侧的垂直旋转性眼球运动，其中1例患者强声刺激能诱发头部运动。所有患者均行颞骨CT检查，并行上半规管重建显示上半规管表面不同程度的骨质缺损。2例患者全身麻醉下行上半规管裂填塞修补术，术后症状明显改善。结论上半规管裂隙综合征的诊断主要依据颞骨高分辨率CT提示上半规管表面覆盖的骨质缺损，同时患者具有相关的前庭耳蜗症状。     

前庭水管扩大综合征患者的人工耳蜗植入术

目的　评价前庭水管扩大综合征患者人工耳蜗植入术的安全性和可行性。方法　 1995年 5月 1日～ 2 0 0 2年 6月 1日因双耳重 极重度感音神经性聋在北京协和医院接受人工耳蜗植入术的患者 312例中诊断为双耳前庭水管扩大者 10例 (3 2 % ) ,其中语前聋 7例 ,语后聋 3例。回顾性分析这 10例患者的临床资料。结果　 10例患者人工耳蜗电极植入顺利 ,8例耳蜗底回开窗时发生轻度井喷 ,迅速用颞肌筋膜牢固封闭圆窗制止井喷。全部患者术后未出现脑脊液漏、颅内感染、面瘫、中耳炎等并发症。开机 6个月时 8例患者具有开放性言语识别力 ,已进入普通学校 (幼儿园、小学、大学 )就读。另 2例语前聋的幼儿视觉强化测听听阈达 4 0dBHL ,与其他无内耳畸形的全聋儿童术后效果差异无显著性。全聋前语言能力较好的 5例患者术后语言能力明显好于语前聋的患者 ,语言交流基本听不出聋人特有的语音特征。另 5例患者语言均有不同程度的进步。结论　尽管前庭水管扩大患者在人工耳蜗植入术中可能出现井喷 ,但术后未出现并发症且听力 言语康复效果好 ,因此重 极重度聋的前庭水管扩大综合征患者行人工耳蜗植入术是安全可行的     

上半规管裂综合征

上半规管裂(SSCD)综合征是由于颅底上半规管骨质缺损所导致,特别是在弓状隆起处。骨迷路缺损导致在硬脑膜和膜迷路之间形成直接连通,形成可移动的第三窗,导致各种听觉和前庭症状。耳鸣和自听增强是最常见的听力学表现,头晕和不平衡是最常见的前庭表现。听力检查的结果根据疾病的严重程度而有所不同,低频传导性听力下降是常见的表现,骨传导阈值可能为负值。SSCD综合征患者患耳的前庭诱发肌源性电位(VEMP)反应阈值通常降低,也可能具有比正常VEMP更大的振幅。颞骨的高分辨率计算机断层(CT)扫描在确诊SSCD中起着重要作用。通常建议使用Pöschl和Stenver重新格式化的视图。外科治疗适用于前庭症状和听力症状严重影响生活质量的患者,有两种主要的手术径路(颅中窝,乳突)和几种技术(封堵、加帽、重铺表面和组合法)。目前,没有足够的证据确切表明哪种手术方法或技术更好。通过颅中窝径路或经乳突径路的手术修复SSCD对听力和前庭症状的改善非常有效且并发症风险较低。     

Posterior semicircular canal dehiscence following endolymphatic sac surgery

Posterior semicircular canal dehiscence is a rare otologic entity that presents with third window signs and symptoms. Petrous apex cholesteatoma, fibrous dysplasia, high riding jugular bulb, and eosinophilic granuloma have been reported to be associated with posterior semicircular canal dehiscence. Here we report a case of development of posterior semicircular canal dehiscence following an endolymphatic sac surgery for the first time. Laryngoscope, 2012.     

Operative management of superior semicircular canal dehiscence

OBJECTIVE: To assess the outcomes of patients undergoing surgical management of superior semicircular canal dehiscence (SSCD). STUDY DESIGN: Retrospective review. METHODS: The medical records of all patients undergoing surgical treatment for SSCD at our institution between 2000 and 2004 were reviewed. RESULTS: Eleven patients underwent unilateral operative management via a middle fossa approach. Ten patients were treated successfully by canal plugging and one unsuccessfully by canal re-roofing. Plugging of SSCD provided resolution of sound- and pressure-induced nystagmus, autophony, and conductive hearing loss (HL). One patient experienced a mild high-frequency sensorineural HL and two patients experienced both a mild high-frequency sensorineural HL and a reduction in vestibular function. Two additional patients underwent exploration for SSCD but were found to have a thin layer of bone overlying the canal. CONCLUSIONS: Plugging of the SSCD, while efficacious in alleviating the symptoms of the disease, may cause loss of labyrinthine function beyond the superior canal.     

Hearing loss in enlarged vestibular aqueduct and incomplete partition type II

Purpose

The purpose of this work is to identify the role of incomplete partition type II on hearing loss among patients with enlarged vestibular aqueduct (EVA).

Enlarged vestibular aqueduct: looking for genotypic–phenotypic correlations

The aim of this work is to provide a guide for clinical and genetic diagnosis and classification of the enlarged vestibular aqueduct syndrome based on a review of the literature and computerized databases with the words large and enlarged vestibular aqueduct. No more than 40 articles described association between the EVA phenotype and a known genetic alteration. Pendred’s syndrome, distal renal tubular acidosis, waardenburg’s syndrome, X-linked congenital mixed deafness, branchio-oto-renal syndrome, and oto-facio-cervical syndrome can express their genotypic alteration as enlarged vestibular aqueduct syndrome. We also found articles reporting familiar cases of enlarged vestibular aqueduct with no identified mutations in studied genes.     

Hemorrhage in the endolymphatic sac: a cause of hearing fluctuation in enlarged vestibular aqueduct

Objective

Most of the patients with enlarged vestibular aqueduct (EVA) experience sudden hearing deterioration, but the exact mechanism is unclear. We analyzed magnetic resonance (MR) images and the cellular components of endolymph obtained from the endolymphatic sac in patients with EVA, in order to demonstrate the cause of sudden hearing loss.

Methods

A total of 25 patients (50 ears) with EVA, who had severe to profound hearing loss, were included in this retrospective clinical study. MR examinations were performed by a 3.0-T MR system using an 8-channel sensitivity-encoding head coil. We analyzed endolymphatic fluid harvested from the endolymphatic sac during cochlear implantations in four patients.

Results

The area of low signal intensity in the endolymphatic sac was observed on T2-weighted MR images for 15 of 50 ears. This area was observed more frequently in patients who experienced recent sudden hearing loss (10/12, 83%) than those with stable hearing (5/38, 13%)(Fisher's exact test, p < 0.001). In addition, this area showed high signal intensity on fluid attenuated inversion recovery images. Cytologic analysis of the aspirated endolymph from the endolymphatic sac in the patients with this area revealed many erythrocytes.

Conclusion

Our data suggests that hemorrhage in the endolymphatic sac could be a cause of sudden hearing deterioration in patients with EVA.     

Superior semicircular canal dehiscence in a young child: implication of developmental defect

In recent years, superior semicircular canal dehiscence (SSCD) has been recognized as a structural cause of a number of auditory and vestibular symptoms, such as vertigo and conductive hearing loss. Prior clinical studies on SSCD have commonly described this entity in adults, but rarely in the pediatric population. We present a pediatric patient with right-sided SSCD which was initially diagnosed radiographically at age seven. This rare and unique case demonstrated SSCD can be found in young children, although the majority of patients with SSCD are adults. It also provides strong evidence that canal dehiscence may be a developmental defect.     

Superior semicircular canal dehiscence: positive predictive value of high-resolution CT scanning

Patients with superior dehiscence (SCD) syndrome present with vertigo and oscillopsia evoked by loud sounds and changes in middle ear or intracranial pressure. The first objective of this retrospective cohort study is to demonstrate that thin-section computed tomography (CT) scans reformatted in the plane of the superior semicircular canal (SSC) overestimate this anomaly compared to pathologic studies. The second objective of this study is to re-evaluate the positive predictive value of temporal bone scanning. All temporal bone CT scans with 0.55-mm collimation and reconstruction in the SSC plane performed over a 1-year period were analysed at a tertiary referral centre. CT-positive cases had their clinical data reviewed and patients were re-examined, if available. A total of 581 temporal bone CT-scans were analysed. A dehiscent-appearing superior canal was seen in 4.0% of studies while published pathologic studies report that only 0.5% of temporal bones SSCs have a dehiscence (P < 0.001). Of the 21 patients with positive temporal bone CTs, only 1 presented with sufficient clinical dues to identify the syndrome. Three additional patients did not have symptoms consistent with the diagnosis, but had surgery for a dehiscence of the tegmen mastoideum. When our findings are added to published data, the positive predictive value of temporal bone CT-scanning drops from 93 to 57%. The prevalence of dehiscent-appearing superior canal on thin-section temporal bone scanning with reformation in the SSC plane is much higher than anticipated by pathologic studies. Even with 0.55 mm-collimated helical CT and reformation in the SSC plane, the risk of overdiagnosis is present.     

人工耳蜗在前庭水管扩大患者中的应用

目的　研究前庭水管扩大患者人工耳蜗植入手术的经验。方法　对 15例 (15耳 )双侧前庭水管扩大伴重度感音神经性聋的患者行多导人工耳蜗植入术 ,并对术后结果进行随访。经面隐窝径路行人工耳蜗植入术 ,在圆窗龛前下方行鼓岬钻孔 ,植入多导人工耳蜗电极。结果　①术中电极完全插入耳蜗 ,其中 6耳出现轻微井喷 ;②术后无面瘫、脑脊液耳漏等并发症 ;③所有患者人工耳蜗植入术后都有听觉 ;④术后听阈与耳蜗结构正常植入患者无明显区别 (自由声场平均听阈 30dBHL) ;⑤术后语训在北京同仁医院或中国聋儿康复中心进行 ,听力及言语能力均有不同程度提高 ,其中 2例患者已经进入正常学校就读。结论　前庭水管扩大伴重度感音神经性聋的人工耳蜗植入与耳蜗结构正常患者植入术后效果基本一致 ,人工耳蜗植入可以作为前庭水管扩大伴有重度感音神经性聋的治疗和康复手段     

95例大前庭水管综合征的临床分析

目的　调查大前庭水管综合征 (largevestibularaqueductsyndrome,LVAS)的发病、遗传和听觉损失情况 ,探讨LVAS之前庭水管外口宽度与听力损失的关系。方法　回溯性搜集 1 992～ 2 0 0 2年 ,95例 (1 90耳 )双侧LVAS的病史 ,听力和前庭功能检查 ,用每例LVAS颞骨CT片的标尺 ,测量前庭水管外口的宽度。结果　 95例 (1 90耳 )LVAS中 ,男 65例 ,女 30例 ,男女比为 2 2∶1。有家族史者 1 2例(1 2 6 % )。平均就诊年龄 7 6岁 ,年龄范围从 1 2～ 39岁。本组绝大多数误诊 ,因轻度外伤而致重度感音神经性聋 2 1例 (2 2 % ) ;上呼吸道感染致聋 1 3例 (1 3 6 % ) ,误诊为突发性聋 9例 (9 5 % ) ;拟诊氨基糖甙类中毒 5例 (5 3 % )。重度感音神经性聋 1 72耳 ,占 92 4%。 77例 (1 54耳 )前庭水管外口宽度( x±s)为 (7 5± 1 2 )mm ,听力损失与外口宽度不成比例。听力损害可能与富含蛋白的内淋巴从内淋巴囊倒流于耳蜗和前庭有关。结论　LVAS是独立的疾病 ,具有波动性及进行性感音神经性聋。诊断依靠颞骨CT扫描或磁共振成像 (magneticresonanceimaging ,MRI)。若听力波动后能改善可保守治疗 ,若明显听力下降 ,影响学习 ,可考虑采用耳蜗植入术     

Quantification of hearing loss in patients with posterior semicircular canal dehiscence

Conclusion: Patients with posterior semicircular canal dehiscence (PSCD) have low frequency conductive hearing loss similar to patients with superior semicircular canal dehiscence (SSCD) secondary to a pathologic third window. Objectives: PSCD can result in conductive hearing loss, but the magnitude of this hearing loss remains to be quantified. Patients with SSCD have been shown to have low frequency conductive hearing loss. The underlying pathophysiology of hearing loss from PSCD and SSCD is similar and related to a pathologic third window. Method: A PubMed search was completed for a meta-analysis of patients with PSCD. Articles with quality audiograms were obtained. Air conduction thresholds for ears with posterior semicircular canal dehiscence were compared to the opposite ear as well as normal control data. Results: Eight articles with 21 patients with PSCD and quality audiograms were included. Two patients had bilateral PSCD and one of those was excluded because hearing thresholds were at the limit of the audiometer. Patients with posterior semicircular canal dehiscence have statistically significant lower air conduction thresholds in frequencies at and below 2000 Hz.     

基因芯片联合DNA测序法在大前庭水管综合征患者基因诊断中的应用

目的应用基因芯片联合DNA测序法对大前庭水管综合征患者进行基因突变检测,分析中国人患者的基因型及探讨其基因诊断策略。方法采集30例大前庭水管综合征患者的外周血,提取基因组DNA。耳聋基因芯片筛查SLC26A4基因的2个突变ⅣS7-2A>G和H723R,发现纯合突变或复合杂合突变即停止筛查。如未发现突变或发现单纯杂合突变则采用DNA测序法检测SLC26A4基因其余外显子,直至发现另一个突变。如仍未发现突变则检测FOXI1基因。结果在30例大前庭水管综合征患者中,基因芯片法联合DNA测序法共检出28例有SLC26A4基因突变(93.33%)。共发现16种突变类型,其中ⅣS7-2A>G突变的发生率最高,其次为H723R。新发现4种突变类型(G368X、ⅣS8-1G>T、ⅣS13+9C>T和Q696X),未发现FOXI1基因突变。结论在中国人大前庭水管综合征患者中,SLC26A4基因的ⅣS7-2A>G突变的发生率最高,其次为H723R。针对这两个突变热点的基因芯片适用于对中国人群进行SLC26A4基因突变的筛查。发现的4例新突变类型对大前庭水管综合征的病因研究和基因诊断具有重要意义。