Smouha E E, Inouye M, Sobol L L, Slepecky N B
Division of Otolaryngology-Head and Neck Surgery, State University of New York at Stony Brook, 11794-8191, USA.
Am J Otol. 1999 Sep;20(5):632-8.
Histologic changes occurring after varying degrees of surgical trauma to the inner ear in guinea pigs can reveal the mechanism of hearing preservation/loss.
Surgical approaches to the inner ear that allow for hearing preservation have gained increasing acceptance in neurotologic surgery. The mechanisms responsible for hearing preservation and hearing loss after partial labyrinthectomy are as yet poorly understood.
Ten animals underwent semicircular canal occlusion, suctioning of perilymph, ampullectomy, or wide vestibulotomy. Tone-burst auditory brain stem response (ABR) thresholds were performed at weekly intervals after surgery. After 4 weeks, temporal bone specimens were processed to obtain 10-jim sections from plastic-embedded ears. The histologic findings were correlated with the initial and final ABR thresholds.
After surgical occlusion of one or more semicircular canals, ABR thresholds were preserved, as the authors reported previously. Suctioning of inner ear fluid led to transient loss of thresholds with recovery. Ampullectomy produced dichotomous results, with some subjects preserving auditory function and others losing auditory function. Wide vestibulotomy resulted in permanent loss of auditory function in most cases. Histologically, there was intraluminal fibrosis and inflammation near the site of surgical entry. Most specimens showed normal cochlear architecture and hair cell counts, irrespective of the degree of hearing loss. Vestibular hair cells were also well preserved, even when they were close to the site of surgical injury.
These findings suggest that electromechanical changes, rather than cell death, are responsible for changes in auditory and vestibular function after partial labyrinthectomy.
豚鼠内耳受到不同程度手术创伤后发生的组织学变化可揭示听力保留/丧失的机制。
在内耳手术中能够保留听力的手术方法在神经耳科学手术中越来越被接受。部分迷路切除术后听力保留和听力丧失的机制目前仍知之甚少。
对10只动物进行半规管闭塞、外淋巴抽吸、壶腹切除术或广泛前庭切开术。术后每周进行短纯音听性脑干反应（ABR）阈值检测。4周后，对颞骨标本进行处理，从塑料包埋的耳朵中获取10微米厚的切片。将组织学结果与初始和最终ABR阈值进行关联分析。
正如作者之前所报道的，手术闭塞一个或多个半规管后，ABR阈值得以保留。内耳液体抽吸导致阈值短暂丧失但随后恢复。壶腹切除术产生了二分结果，一些受试者保留了听觉功能，而另一些则丧失了听觉功能。在大多数情况下，广泛前庭切开术导致听觉功能永久性丧失。组织学上，手术入口部位附近存在管腔内纤维化和炎症。大多数标本显示耳蜗结构和毛细胞数量正常，与听力损失程度无关。即使前庭毛细胞靠近手术损伤部位，也保存良好。
这些发现表明，部分迷路切除术后听觉和前庭功能的变化是由机电变化而非细胞死亡引起的。
