先天性外耳和中耳畸形患者的听力学分析

Audiological Assessment of Patients with Congenial External and Middle Ear Malformations

目的探讨不同程度的先天性外、中耳畸形患者的听力学表现。方法对55例(双耳15例,单耳40例,共70耳)先天性外、中耳畸形患者行纯音测听、听性脑干反应(ABR)和颞骨CT检查,其中45耳行外耳或中耳成形术,10耳单纯行耳廓成形术,并结合术中所见按不同程度的畸形分组,比较其听力学改变。结果63耳纯音测听显示为传导性聋,骨导听阈正常,70耳ABR反应阈升高,耳廓和听骨链畸形严重者纯音听阈值大于70dB(其中镫骨和卵圆窗畸形严重者纯音听阈大于80dB),与畸形程度较轻者差异有统计学意义(P<0.05)。乳突气化差、外耳道骨性闭锁者纯音听阈值大于70dB(其中外耳道口处无骨性小凹者纯音听阈值大于70dB),较外耳道、乳突发育好者差异有统计学意义(P<0.05)。结论对先天性外、中耳畸形患者术前进行纯音测听、ABR检查,并结合临床和颞骨CT检查,可初步评估外耳、中耳发育程度,进而指导手术治疗。

Objective To investigate the hearing loss of the cases with congenial external and middle ear malformation. Mothods Pure tone audiometry, auditory brainstem response （ABR） and CT were conducted in 55 cases. Among them, 45 ears received operations and subsequently, their hearing was retested and compared. Results 63 ears receiving air conduction testing, had conductive hearing loss but with normal bone conduction thresholds. ABR estimated thresholds were elevated in 70 ears. Patients with severely malformed auricles and ossicular chains had more than 70 dB air conduction thresholds. Those with malformed mastoids, stapes and oval windows had air conduction threshold higher than 80 dB. Statistically different results were found between the group with severe and that with mild tnalformations （ P 〈 0.05）,and so were those between the pneumatic type of mastoid processes and the osteal atresia of external ear canals and the other cases. Conclusion Using pure tone andiometry and ABR, in addition to CT, we can clinically assess the hearing status and the development of external and middle ear, thus guiding the clinician in handling with difficult surgery.