胆脂瘤型中耳炎患者鼓室成形术前后骨导听力变化的观察

目的　探讨单侧胆脂瘤型中耳炎患者接受鼓室成形术后骨导听力的改变。方法　对 1995～ 1999年间住院的 188例接受鼓室成形术的单侧胆脂瘤型中耳炎患者手术前后的骨导听阈进行分析 ,以 0 .5、1.0、2 .0、4 .0、6 .0kHz至少 2个频率骨导听阈改变超过 15dBHL以上为阳性 ,否则为阴性。记录阴、阳性例数 ,并比较术前阴、阳性组之间在术中所见的听骨链固定或坏死、前庭窗或蜗窗功能不良的发生率的差异。结果　与健侧对比 ,4 4例(2 3.4 % )术前为阳性 (阳性组 ) ,14 4例 (76 .6 % )为阴性 (阴性组 ) ,阳性组中 5 6 .8% (2 5 / 4 4 )术后骨导听力改善 ,术中发现听骨链或两窗功能不良的有 75 % (33/ 4 4 ) ,较阴性组的 10 .4 % (15例 )高 (P <0 .0 1)。结论　在部分接受鼓室成形术的单侧胆脂瘤型中耳炎患者中 ,术前骨导听力可因听骨链和两窗功能不良而下降 ,但部分病例术后骨导听力可以有所改善。

Bone Conduction Variation Before and After Tympanoplasty in Cholesteatoma

Objective To study the changes of bone conduction threshold after tympanoplasty in patients with unilateral cholesteatoma.Methods The records of 188 cases were reviewed. Preoperatively, 15 dB or more depression of Bone conduction threshold at least in 2 frequencies from 500 to 6,000 Hz was considered to be significant,comparing to the normal ear. Similarly in postoperative period, 15 dB or more improvement of bone conductive threshold at least in 2 frequencies from 500 to 6,000 Hz was regarded as significant.The following findings were recorded and compared between depressed and undepressed cases:the difference of occurrence of ossicular necrosis or fixation, or dysfunction of oval and/or round window.Results Fourty-four (23.4%) of 188 cases were found to have depressed bone conductive threshold. Among them,25 of 44(56.8%) cases had improvement of bone conductive threshold after tympanoplasty. The occurrence of ossicular necrosis or fixation, or dysfunction of the oval and/or round window found surgically in the depressed group was 75%(33 of 44 cases), significantly higher than that of 10.4%(15 of 144 cases) in the undepressed group(P<0.01).Conclusion In some patients with choleasteatoma, depressed bone conductive threshold is associated with the ossicular necrosis or fixation and dysfunction of the oval and/or round windows. Some of the depressed bone conduction threshold will be improved after tympanoplasty.