摘要
目的 探讨不同功率Nd∶YAG激光照射鼓膜对内耳功能和结构的影响。方法 45只豚鼠分 3组 ,每组 15只。分别以光纤末端功率为 8、6、4W的Nd∶YAG激光针对鼓膜作接触式照射 ,照射时间均为2s。激光照射前、照射后即刻及 2周 ,分别测试听性脑干反应 (ABR)阈值 ,并应用光镜和扫描电镜技术观察耳蜗形态学变化。结果 激光照射后即刻 3组ABR阈值均升高 (P <0 0 1) ,8W组较 4W组升高明显 (P <0 0 5 ) ;照射后 2周 8、6W组ABR阈值虽然较照射后即刻有所降低 ,但仍高于照射前 (P <0 0 5 ) ,而 4W组则恢复至照射前水平。照射后即刻 ,8、6W组耳蜗外毛细胞出现肿胀 ,硝酸银浓染 ,血管纹血管扩张 ,4W组无明显改变 ;照射后 2周 ,8W组外毛细胞平均损失达 45 % ,6W组平均损失2 0 % ,内毛细胞也均有少量缺失 ,4W组内、外毛细胞形态基本正常。结论 应用Nd∶YAG激光治疗中耳疾病时 ,光纤末端输出功率应控制在 4W ,照射时间以 2s为宜 ,否则可能会导致不可逆的听力下降。
Objective To explore the effect of Nd∶YAG laser irradiation to tympanic membrane on the structure and function of inner ear. Methods Guinea pigs were equally divided into 3 groups. Their tympanic membrane were irradiate for 2 seconds by Nd∶YAG laser with output power of 4 W, 6 W or 8 W, respectively for each group. The ABR thresholds was measured before, immediately after and two weeks after irradiation. Cochlear sections were prepared. Light and scanning electron microscopies were performed to observe the morphological alteration. Results The experiment elucidated that impairment of inner ear was correlated with laser output power and the thresholds of ABR were elevated after irradiation. Although the ABR threshold 2 weeks after irradiation in 8 W and 6 W group respectively was lower than that immediately after irradiation, but was still higher than that before irradiation(P<0 05). No significance was noted in group 4 W. Immediately after irradiation, swelling and deeply staining of outer hair cells and dilation of stria vascularis were present in cochlea in group 8 W and group 6W, without obvious injurg in group 4 W. Two weeks later, the outer hair cells loss rates were 45% and 20% in group 8 W and group 6 W, respectively. There were also some loss of inner hair cells. The hair cells of group 4 W were intact. Conclusions In the Nd∶YAG laser treatment of middle ear disease, the appropriate output power is 4 W and appropriate irradiation duration 2 seconds to protect inner hair cells from injury .
出处
《中国激光医学杂志》
CAS
CSCD
2000年第2期89-92,共4页
Chinese Journal of Laser Medicine & Surgery
关键词
激光照射
鼓膜
耳蜗
听性脑干反应
Lasers
Tympanic membrane
Cochleas
Auditory brainstem response
