Awengen D F
Division of Otolaryngology, Head and Neck Surgery, Stanford University Medical Center, CA.
Am J Otolaryngol. 1993 Mar-Apr;14(2):105-10. doi: 10.1016/0196-0709(93)90048-c.
The influence of age on threshold changes of bone conduction after stapedectomy has not been thoroughly studied. Improvement of the Carhart notch by stapes surgery might be related to age as well as an increase in cochlear sensitivity to surgical trauma.
A retrospective study on the outcome of stapedectomy was undertaken. The results of surgery performed on 387 ears in 315 patients for otosclerosis between 1962 and 1989 were obtained. Stapedectomy, performed by a single surgeon, consisted of total stapedectomy, seal of the oval window with tragal perichondrium, and insertion of a free tragal cartilage graft.
Analysis of bone conduction changes with stapedectomy shows an average improvement of 5 to 6 dB at 0.5, 1, and 2 kHz with best improvement at 2 kHz. At 4 kHz a mean decrease of 4 dB is recognized. The improvement of bone conduction at 2 kHz is 12 dB in patients younger than 30 years compared with 4 dB in patients older than 60 years (P < .05). The youngest group was improved by 2 dB at 4 kHz, whereas the oldest group deteriorated by 5 dB (P < .05). Age relationship was apparent in all 4 frequencies.
With increasing age there is less improvement in bone conduction at 0.5, 1, and 2 kHz with correction of the Carhart notch and more deterioration at 4 kHz. The cochlear sensitivity to surgical trauma increases with age. In younger patients the preoperative bone conduction levels do not reflect the true cochlear reserve. Patients younger than 40 years of age might profit more from a partial or total footplate removal in stapedectomy, as this better corrects the Carhart notch. Patients older than 40 years of age might profit from a stapedotomy as this better preserves high frequencies.
年龄对镫骨切除术后骨导阈值变化的影响尚未得到充分研究。镫骨手术对卡哈特切迹的改善可能与年龄有关，也与耳蜗对手术创伤的敏感性增加有关。
对镫骨切除术的结果进行了一项回顾性研究。获取了1962年至1989年间315例患者387耳因耳硬化症接受手术的结果。由一名外科医生进行的镫骨切除术包括全镫骨切除术、用耳屏软骨膜封闭卵圆窗以及植入游离耳屏软骨移植物。
对镫骨切除术后骨导变化的分析显示，在0.5、1和2kHz时平均改善5至6dB，在2kHz时改善最佳。在4kHz时平均下降4dB。30岁以下患者在2kHz时骨导改善为12dB，而60岁以上患者为4dB（P<.05）。最年轻组在4kHz时改善2dB，而最年长组恶化5dB（P<.05）。在所有4个频率中年龄关系均明显。
随着年龄的增长，在0.5、1和2kHz时通过纠正卡哈特切迹骨导改善较少，而在4kHz时恶化更多。耳蜗对手术创伤的敏感性随年龄增加。在年轻患者中，术前骨导水平不能反映真正的耳蜗储备。40岁以下的患者可能从镫骨切除术中部分或完全去除镫骨底板中获益更多，因为这样能更好地纠正卡哈特切迹。40岁以上的患者可能从镫骨足板造孔术中获益，因为这样能更好地保留高频。
