大前庭水管综合征(LVAS)的研究进展

大前庭水管综合征(LVAS)是先天性内耳畸形的一种类型。前庭水管(VA)在胚胎发育时期受阻导致VA异常扩大,扰乱了内淋巴循环的平衡,导致耳蜗神经上皮损伤,产生神经性耳聋。LVAS的基因研究示常染色体隐性遗传最为多见,与该疾病有关的基因位于7q31,与PDS基因重选。临床上主要表现为儿童时期的听力损失,有家族发病倾向,听力学检查以感音神经性聋为主,呈进行性下降的趋势。外伤、剧烈运动可诱发眩晕及突聋。影像学检查有特征性改变。目前保守治疗主要针对突发性听力下降,手术治疗的效果十分有限。对于LVAS伴双侧重度感音神经性聋(SNHL)的患儿来说电子耳蜗植入是安全有效的。     

Therapeutic approach in managing patients with large vestibular aqueduct syndrome (LVAS)

Objective

To discuss the clinical approach in managing patients with large vestibular aqueduct syndrome.

Methods

Over the period from November 1997 to March 2005, 106 children have been fitted with cochlear implants in Antwerp University Hospital (UZA). The Hospital University of Maastricht (azM) had implanted 36 children since 1999 to March 2005. The present study focuses on nine children and one adult patient with large vestibular aqueduct syndrome (LVAS). The medical, report and radiology report were retrospectively analysed.

Results

Eight out of nine children with LVAS had been implanted and one child was on the waiting list. One adult patient was implanted with Nucleus 24 M at the age of 22 years old. Nine out of 10 patients had bilateral large vestibular aqueduct. There were no intraoperative or postoperative complications encountered.

Conclusion

Cochlear implantation is a safe operation for patients with LVAS.     

大前庭水管综合征患者误诊与漏诊原因分析

目的 了解大前庭水管综合征(large vestibular aqueduct syndrome,LVAS)患者的临床特征,分析造成误诊和漏诊的原因.方法 观察19例被误诊或漏诊的LVAS患者,详细了解诊治经历,行纯音测听、声导抗测听及脑干诱发电位等听功能检查,所有患者均行颞骨高分辨CT检查.结果 19例患者确诊年龄为...     

大前庭导水管综合征

大前庭导水管综合征(large vestibular aqueduct syndrome，LVAS)是以前庭导水管扩大伴有感音神经性耳聋为特征的一种临床独立病症．由Valvassori等于1978年首先描述并正式命名。是先天性内耳畸形的一种．Okurnara等进一步将其分为合并耳蜗畸形(如Mondini畸形)与不合并耳蜗畸形两个亚型．但前者不列入LVAS的范畴。其临床发     

The large vestibular aqueduct syndrome

The hypocycloidal polytomographic temporal bone studies performed on 2683 patients were reviewed, and the radiographic appearance of the vestibular aqueduct was evaluated. Within this group of 5366 ears, forty-seven ears (1%) in twenty-six patients demonstrated a large vestibular aqueduct (diameter greater than 1.5 mm). A review of the relevant embryology, anatomy, and physiology is reported. A discussion of hypocycloidal polytomography and computed tomography of the temporal bone as well as a discussion of the Mondini dysplasia is also presented. The twenty-six patients underwent a battery of audiometric and vestibular function tests. These data were compiled and correlations made, allowing for a more complete characterization of the large vestibular aqueduct syndrome.     

The large vestibular aqueduct syndrome

It has long been known that abnormally large vestibular aqueducts may accompany congenital malformations of the cochlea and semicircular canals. Recently, enlargement of the vestibular aqueducts as the sole radiographically detectable inner ear anomaly has been recognized as a distinct pattern of congenital inner ear malformation. Pathogenesis of the large vestibular aqueduct syndrome probably stems from an early derangement in the embryogenesis of the endolymphatic duct. This anomaly appears to be relatively common in children with sensorineural hearing loss and is probably significantly underdiagnosed. Hearing loss is typically bilateral and progressive, with stepwise rather than fluctuant hearing decrements often triggered by relatively minor head trauma. A review of 17 patients (33 ears) revealed an average hearing level at presentation of 57 dB with a speech discrimination score of 66%. Considerable variability exists in hearing level among affected ears, ranging from normal hearing (4%) to profound deafness (39%). In 12 patients (23 ears) with an average long-term follow-up of 7.3 years, the hearing loss progressed by an average of 25 dB, with a drop of 29% in speech discrimination over the period of observation. An endolymphatic to subarachnoid shunt was performed on seven ears in an effort to stabilize hearing. Four of these ears had a substantial immediate postoperative drop in hearing. For this reason, endolymphatic sac surgery is not recommended for patients with this deformity.     

Mutations of the Pendred syndrome gene (PDS) in patients with large vestibular aqueduct

A recent report demonstrated the presence of a mutation in the Pendred syndrome gene (PDS) of patients with large vestibular aqueducts but without goitre. We studied PDS mutations in members of four Japanese families, among which five affected members showed bilateral enlarged vestibular aqueducts. All affected members exhibited moderate to severe bilateral fluctuating sensorineural hearing loss and the absence of goitre. Three members also suffered from recurrent episodic vertiginous spells. Analysis of PDS mutation revealed two single base changes (mis-sense mutations) in exons 19 and 10. The first was an A-->G transition at nucleotide position 2168, resulting in a predicted His-->Arg substitution at position 723 (H723R), whereas the second was a C-->T transition at nucleotide position 1229, resulting in a predicted Thr-->Met substitution at position 410 (T410M). Both mutations are situated in the extracellular domain close to the C terminal. It thus appears that PDS mutations can lead not only to classic Pendred syndrome, but also to large vestibular aqueduct syndrome.     

大前庭水管综合征临床特征分析(附10例报告)

目的分析大前庭水管综合征(1arge vestibular aquduct syndrome,LVAS)临床特征.方法分析10例(20耳)临床资料,主要分析其诱因、临床表现、听力学检查、CT及MRI资料.结果10例均双侧发病.病前有感冒史1例、头部外伤史1例;重度感音神经性聋9例,有眩晕发作2例;突发性加重聋4例、经治疗后听力恢复到发病前状况2例;1例患者(发病时有眩晕发作,平衡功能检查在治疗后第11天进行)行平衡功能检查,结果为重心动摇图睁眼、闭眼呈中间型,双侧视动反应正常,双侧冰水试验无反应;所有患者DPOAE均未引出;所有患者HRCT显示大前庭水管3.0-6.5mm(4.3±1.1mm);行颞骨MRI检查1例,T2相前庭水管及内淋巴囊扩大.结论目前LVAS诊断依赖颞骨CT或MRI,保守治疗疗效不明确,早期诊断早期预防是关键.     

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     

双侧大前庭导水管综合征7例报告

目的：探讨双耳均为大前庭导水管综合征病例的ＣＴ和听力改变特征。方法：对７例经高分辨率ＣＴ证实为双耳大前庭导水管综合征病例的导水管管径和听阈改变进行分析。结果：ＣＴ示扩大的前庭导水管的管径两耳不对称,管径较大侧耳的听力损失重,差异有显著性意义（Ｐ〈０．０５）。结论：测量前庭导水管的管径对估计听力损失的程度和预后有重要意义。     

The large vestibular aqueduct syndrome.

The radiographic observation of 50 patients, each having an enlarged (greater than 1.5 mm. diameter) vestibular aqueduct, are analyzed. In addition to the aqueduct other associated inner ear anomalies have been identified in 60% of this population including: enlarged vestibule (14); enlarged vestibule and lateral semicircular canal (7); enlarged vestibule and hypoplastic cochlea (4); and hypoplastic cochlea (4). The large equeduct then presumably represents an arrested phase of inner ear development common to all 50 cases. Only 8 of these cases may fall into the Mondini or Mondini-Alexander classification wherein cochlear abnormalities have been identified. The size of the aqueduct ranged from 1.5 to 8 mm. in the anteroposterior diameter; the clinical incidence is 50 in 3700 consecutive cases referred for inner ear tomography. Bilateral involvement is twice as common as unilateral with a female to male predominance of 3:2. Most cases are associated with congenital hearing losses.     

大前庭水管综合征的研究进展

大前庭水管综合征（large vestibular aqueduct syndrome，LVAS），又称先天性前庭水管扩大，由Valvassori等”0于1978年首先描述并正式命名。Okumura等进一步将其分为合并耳蜗畸形（如Mondini畸形）与不合并耳蜗畸形两个亚型，但前者不列入LVAS的范畴。随着影像学和分子生物学的发展，对LVAS的研究也逐渐深入。我们就LVAS的病因与发病机制、SLC26A4基因突变与LVAS、临床表现、诊断、预防与治疗作一综述。     

Clinical analysis of 95 patients with large vestibular aqueduct syndrome]

OBJECTIVE: To investigate the occurrence, genetic inheritance, and hearing loss conditions of large vestibular aqueduct syndrome (LVAS), and to measure the width of external aperture of vestibular aqueduct (VA) of LVAS, and to analyze the relationship between the hearing loss and the width of external aperture. METHODS: A retrospective review was conducted by the history, auditory, and vestibular function examinations in 95 patients (190 ears) of LVAS. The width of VA was measured by CT scanning criterion of each LVAS patients in the past 10 years (from 1992 to 2002). RESULTS: In 95 patients, there were male 65 cases and female 30 cases. The male cases was more than the females by a ratio of 2.2:1. Twelve cases (12.6%) would have familial genetic history. The average of the consult age was 7.6 years (range from 1.2 to 39 years). The most patients were misdiagnosed, the hearing deterioration originated from mild head trauma in 21 cases (22.1%), the hearing loss after common cold in 13 cases (13.6%). Nine cases (9.5%) misdiagnosed as sudden hearing loss, 5 cases (5.3%) as ototoxic hearing loss of Aminoglycoside antibiotic. The profound hearing loss was found in 172 ears (92.4%). The average width of external aperture of LVAS was 7.5 mm +/- 1.2 mm (mean +/- s, 77 cases, 154 ears). The level of hearing loss did not proportional to the width of VA. The hearing impairment could be derived from protein-rich endolymph refluxed into the cochlear and vestibule. CONCLUSION: The LVAS is distinct clinical entity characterized by fluctuate and progressive SNHL. The diagnosis depends upon the CT scan and MR image. If the hearing fluctuated and subsequently improved, the children were kept under conservation treatment. If the significantly decreased of hearing effected school performance, the cochlear implant might be considered.     

Cochlear implantation in children with large vestibular aqueduct syndrome

OBJECTIVE: This study describes the effectiveness of a multielectrode cochlear implant prosthesis (Cochlear; Cochlear Pty., Lane Cove, Australia) for providing hearing to children with deafness caused by large vestibular aqueduct syndrome (LVAS). STUDY DESIGN: The study design was a retrospective study. SETTING: All the children attended The Children's Cochlear Implant Center (NSW), which is a specialist center that provides audiologic testing, speech therapy, habilitation, and medical assistance for children with cochlear implants. PATIENTS: Ten children were studied who had profound hearing loss and radiologic evidence of a vestibular aqueduct larger than 2 mm in width in its intraosseous portion. INTERVENTION: The children received a multielectrode (Cochlear) cochlear implant prosthesis, and the associated programming of the device and habitation were performed postoperatively. No significant problems were encountered at any of the surgeries, although there was an initial gush of perilymph when the otic capsule was opened in 7 ears. MAIN OUTCOME MEASURES: Postoperative audiologic performance at six monthly intervals and school performance were assessed. RESULTS: The postoperative auditory performance was improved in all children. At 6 months, their average BKB score had increased from 31% to 79%; average word score, from 8% to 43%; and average phoneme score, from 38% to 70%. The older children were able to continue their education in their usual setting with less reliance on hearing support staff. CONCLUSION: Children with a deteriorating hearing loss caused by LVAS can derive considerable benefit from a cochlear implant.     

Audiological findings in large vestibular aqueduct syndrome

An enlarged vestibular aqueduct is a congenital disorder causing early onset and progressive hearing loss in children. This paper presents the audiological findings at first presentation and the audiological evolution in 10 consecutive cases presenting with hearing loss and showing a large vestibular aqueduct on imaging. The reported onset of the hearing loss is within the first few years of life. Most of the cases (80%) showed bilateral involvement. The sex ratio was 1. Patients presented on average at age 5 with a median hearing loss of 62 dB at the speech frequencies. The hearing loss was essentially asymmetrical with an interaural difference, of 33 dB and it was a mixed type of hearing loss in 90% of the cases. The authors claim that the conductive component of this hearing loss is a pure cochlear conductive loss which may be pathognomonic for the disease. The presence of a conductive component in a child is easily misinterpreted as a middle ear ventilation problem or in case of good ventilation as an ossicular problem (type otosclerosis). In addition and in contrast to most literature data, the authors did not find evidence for stabilization of the hearing loss but they found a steady decrease of the hearing at an average rate of 4 dB/year.     

Chronological changes of hearing in pediatric patients with large vestibular aqueduct syndrome

OBJECTIVES: To describe the chronologic changes of hearing in patients with large vestibular aqueduct syndrome (LVAS) and identify the prognostic factors. STUDY DESIGN: A retrospective chart-review study. METHODS: Twelve consecutive patients with LVAS were recruited at Taipei Veterans General Hospital between July 1986 and July 2000. The records of serial pure-tone audiogram and high-resolution computer tomography were collected. The chronologic figures of pure-tone average (PTA) were sketched. The investigated variables included sex, laterality and type of hearing loss (HL), size of vestibular aqueduct, and the chronologic changes and configurations of hearing. Data were analyzed statistically. RESULTS: The degree of HL in early childhood was from moderate to profound. The worst hearing could be estimated by the hearing level in early childhood. Sixteen of 24 ears were stable. Bilateral, chronologically stepwise-downhill hearing occurred in only one patient (1/12) during the follow-up period. Chronologically, high-tone hearings were worse than those of low-tone, but fluctuations of high-tone hearing were smaller than those of low-tone. The sizes of vestibular aqueduct were predictive of the density of major depression and its depth. CONCLUSIONS: LVAS, a congenital disease, is characterized by fluctuating sensorineural HL. Most hearing at PTA remained stable at least in one ear chronologically. The standard deviation of hearing at 500 Hz was the only prognostic factor for the progression of PTA. An enlarged vestibular aqueduct affects fluctuations of hearing, but the pathogenesis of HL still remains unclear and deserves further investigations.