Bance Manohar, Morris David P, Vanwijhe Rene G, Kiefte Michael, Funnell W Robert J
The Ear and Auditory Research Laboratory, Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada.
Otol Neurotol. 2004 Nov;25(6):903-9. doi: 10.1097/00129492-200411000-00008.
Ossiculoplasty using prosthetic reconstruction with a malleus assembly to the stapes head will result in better transmission of vibrations from the eardrum to the stapes footplate than reconstruction with a tympanic membrane assembly to the stapes head. Both types of reconstruction will be affected by tension of the prosthesis.
Theories (and some clinical studies) that the shape of the normal tympanic membrane is important suggest that prosthetic reconstruction to the malleus performs better than reconstruction to the tympanic membrane. This has not been previously tested by directly measuring vibration responses in the human ear. Our previous work suggests that tympanic membrane assembly to the stapes head type prostheses performed best under low tension. This had not been previously tested for malleus assembly to the stapes head type prostheses.
Hydroxyapatite prostheses were used to reconstruct a missing incus defect in a fresh cadaveric human ear model. Two types of prostheses were used, one from the stapes head to the malleus (malleus assembly to the stapes head), the other from the stapes head to the tympanic membrane (tympanic membrane assembly to the stapes head). Stapes footplate center responses were measured using a laser Doppler vibrometer in response to calibrated acoustic frequency sweeps.
Tension had a very significant effect on both types of prostheses in the lower frequencies. Loose tension was best overall. The malleus assembly to the stapes head type prostheses consistently performed better than the tympanic membrane assembly to the stapes head type prostheses when stratified for tension.
Tension has a significant effect on prosthesis function. Malleus assembly to the stapes head type prostheses generally result in better transmission of vibrations to the stapes footplate than tympanic membrane assembly to the stapes head type prostheses.
与使用鼓膜组件连接镫骨头进行重建相比，采用带有锤骨组件连接镫骨头的人工修复进行听骨链成形术，能使振动从鼓膜更好地传递至镫骨足板。两种重建方式均会受到假体张力的影响。
正常鼓膜形状很重要的理论（以及一些临床研究）表明，对锤骨进行人工修复重建的效果优于对鼓膜进行重建。此前尚未通过直接测量人耳的振动反应对此进行测试。我们之前的研究表明，在低张力情况下，鼓膜组件连接镫骨头型假体的表现最佳。此前尚未对锤骨组件连接镫骨头型假体进行过此类测试。
在新鲜的尸体人耳模型中，使用羟基磷灰石假体修复缺失的砧骨缺损。使用了两种类型的假体，一种是从镫骨头连接至锤骨（锤骨组件连接镫骨头），另一种是从镫骨头连接至鼓膜（鼓膜组件连接镫骨头）。使用激光多普勒振动计测量镫骨足板中心对校准的声频扫描的反应。
在较低频率下，张力对两种类型的假体都有非常显著的影响。总体而言，松弛的张力效果最佳。在按张力分层时，锤骨组件连接镫骨头型假体的表现始终优于鼓膜组件连接镫骨头型假体。
张力对假体功能有显著影响。与鼓膜组件连接镫骨头型假体相比，锤骨组件连接镫骨头型假体通常能使振动更好地传递至镫骨足板。
