Acoustical modulation of electrically evoked otoacoustic emission in intact gerbil cochlea

In order to study the interaction between mechanical-electrical and electrical-mechanical transductions of outer hair cells (OHCs) in vivo, we observed the acoustically induced changes in the electrically evoked otoacoustic emission (EEOAE). One pole of a bipolar electrode was placed in the round window niche and the other pole on the surface of the first cochlear turn in the gerbil. A microphone and a speaker were used to monitor the EEOAE and to deliver an acoustical tone, respectively. It was found that a high sound level acoustical tone enhanced the EEOAE fine structure at frequencies below the acoustical frequency, and suppressed the overall level of the EEOAE at frequencies above the acoustical frequency. In addition, the EEOAE at frequencies approximately one half octave lower than the acoustical frequencies were relatively more enhanced or showed relatively less suppression than at other frequencies. The amplitudes of these changes had a positive relationship with acoustical tone levels. Furosemide eliminated the acoustically caused EEOAE change indicating that the acoustically caused change in the EEOAE is a phenomenon of the normal cochlea. One possible mechanism for the results is that the electrically and acoustically evoked basilar membrane (BM) vibrations interact at the EEOAE generation site and change the local mechanical and electrical properties. The second possible mechanism is that the acoustical stimulus creates an impedance discontinuity at its characteristic frequency location leading to a change in the reflected electrically evoked traveling wave, which may enhance or suppress the EEOAE by the vector summation of two waves.     

Hair cell loss and regeneration after severe acoustic overstimulation in the adult pigeon

The extent of hair cell regeneration following acoustic overstimulation severe enough to destroy tall hair cells, was determined in adult pigeons. BrdU (5-bromo-2′-deoxyuridine) was used as a proliferation marker. Recovery of hearing thresholds in each individual animal was measured over a period of up to 16 weeks after trauma. In ears with loss of both short and tall hair cells, little or no functional recovery occurred. In ears with less damage, where significant functional recovery did occur, there were always a few rows of surviving hair cells left at the neural edge of the basilar papilla. In the region of hair cell loss, numerous BrdU labeled cells were found. However, only a small minority of these cells were regenerated hair cells, the majority being monolayer cells. Irrespective of the extent of the region of hair cell loss, regenerated hair cells were observed predominantly in a narrow strip at the transition from the abneural area of total hair cell loss and the neural area of hair cell survival. With increasing damage this strip moved progressively towards the neural edge of the papilla. No regeneration of hair cells was observed in the abneural region of total hair cell loss, even up to 16 weeks after trauma. The results indicate that there is a gradient in the destructive effect of loud sound across the width of the basilar papilla, from most detrimental at the abneural edge to least detrimental at the neural edge. Both tall and short hair cells can regenerate after sound trauma. Whether they do regenerate or not depends on the degree of damage to the area of the papilla where they normally reside. Regeneration of new hair cells occurs only in a narrow longitudinal band, which moves from abneural into the neural direction with increasing damage. In the area neural to this band, hair cells survive the overstimulation. In the area abneural to this band, sound damage is so severe, that no regeneration of hair cells occurs. As a consequence morphological and functional deficits persist.     

A longitudinal,functional study of peripheral nerve recovery in the mouse

Objectives: To verify the validity of the recently described sciatic functional index for mice to monitor neuronal functional recovery over time using a blinded, randomized, and controlled evaluation. Study Design: Surgery was performed on the left sciatic nerves of 62 C57/BL mice after randomly assigning them to one of four surgical groups: sham surgery, sciatic nerve crush, nerve transection without repair, and nerve transection followed by epineurial suture repair. Sciatic functional indices were measured before surgery and then after surgery at 10-day intervals for 90 days, using a previously described formula. Results: Sham surgery did not affect nerve function when compared with preoperative values (P > .24). Crush surgery produced a reversible nerve injury that fully recovered after 20 days. Nerve transection without repair resulted in complete functional disability without recovery of function during the 90-day follow-up interval. When transected nerves were repaired, complete functional disability was noted at day 10, with subsequent functional recovery to 26% of function at day 30. This level of recovery persisted until the 60th postoperative day when muscle contractures resulted in progressive worsening of the index. There were statistically significant differences between the sciatic functional indices of each of the groups (P < .05). Conclusions: The previously described sciatic functional index for mice is an accurate indicator of the level of sciatic neuronal function during recovery. This index represents a method of evaluating neuronal function that may provide a better reflection of the recovery parameters that are important in clinical situations. The sciatic functional index will allow for study of sciatic nerve functional recovery in genetically engineered transgenic mice.     

Facial nerve outcome in lateral skull base surgery for benign lesions

Objective: To statistically identify factors most important in affecting CN7 outcome in lateral skull base surgery for benign lesions. Study Design: A retrospective review of 217 nonmalignancy lateral skull base procedures from 1970 to 1995 at the Otology Group in Nashville. Methods: Charts were reviewed for epidemiology, histopathology, staging, type of CN7 mobilization (none, short, long, severance with reanastomosis, and resection), preoperative and postoperative CN7 function, surgery performed, and survival. Results: Average House-Brackman (HB) scores for mobilizations were as follows: short, 1.65: long, 2.74: and grafting, 4.33. Factors found to affect outcome in a statistically significant fashion were preoperative HB score, staging, type of CN7 manipulation, and surgical approach. Meningiomas were found to have a worse outcome than glomus tumors. Conclusions: Complete resection of tumors should be performed with minimal manipulation of the facial nerve based on regional anatomy and tumor anatomy. Laryngoscope, 108:1480–1484, 1998     

Computer-aided 3-D reconstruction and measurement of the optic canal and intracanalicular structures

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经皮穴位电刺激配合全麻行异氟醚控制性降压的可行性研究

目的:研究经皮穴位电刺激配合全麻行异氟醚控制性降压的临床使用可行性。方法:选择脑瘤择期手术患者4 2例,随机分为对照组和实验组,对照组采用常规全麻,实验组经皮穴位电刺激加常规全麻,各2 1例。术中用HANS电针仪电刺激双侧颧、鱼腰、风池及合谷等穴位,同时加大异氟醚浓度,使平均动脉压(MAP)较麻醉前下降30 %～4 0 %,维持30～4 5min ,观察以下项目:①两组于剪脑膜后降压前、降压30min及血压回升稳定后30min各阶段的血流动力学指标及组织氧代谢、相应血气和动脉乳酸浓度等指标。②两组降压前、中、后呼气末异氟醚浓度的变化。③麻醉苏醒恢复状况。结果:①两组动脉及肺混合静脉血气值各项指标均无明显变化,且均在正常值范围中;两组间同一时相比较,差异无显著性。②与降压前比较,降压期间肺动脉混合静脉血氧饱和度和组织氧供下降,氧摄取率增加,差异均有显著性(P <0 .0 5 ) ;DO2 、VO2 、ERO2 、SvO2 、CO、CI和ABL等指标降压中与降压前增减的百分数,实验组明显低于对照组(P <0 .0 5 )。③Sv、SI和LVSWI等参数绝对值,对照组、实验组之间同一时相比较无明显差异,而降压30min与降压前增减的百分数,实验组明显低于对照组,有显著性差异(P <0 .0 5 )。④与对照组比较,实验组在降压前、中、后呼气末吸入的异氟?     

视神经鞘脑膜瘤的显微外科治疗(附13例报道)

目的探讨视神经鞘脑膜瘤的显微神经外科手术方法。方法收治13例视神经鞘脑膜瘤，根据肿瘤位置采用3种不同经颅入路：单侧额部入路、经额经眶上缘入路及经额颧经眶上缘入路，利用显微外科技术安全显露眶上裂外侧部、眶上裂中央部切除肿瘤。结果肿瘤全切11例，部分切除2例。术后13例患者的眼球突出均恢复正常，11例其它症状和体征也恢复或改善。术后动眼神经麻痹1例，患侧眼失明2例。结论熟悉显微神经外科解剖学，利用显微外科技术选择合适的经颅入路，可以提高视神经鞘脑膜瘤的全切除率，并使颅眶区的正常结构得到最大程度的保护。     

甲状腺切除术中喉返神经损伤的预防

目的探讨甲状腺手术中喉返神经损伤的预防措施。方法回顾性分析手术治疗282例甲状腺切除术的临床资料。结果暂时性喉返神经损伤6例。结论熟悉喉返神经的正常解剖和变异，仔细操作，灵活掌握显露喉返神经的方法和指征，是预防喉返神经损伤的关键。     

皮神经营养血管岛状皮瓣修复肢体创面及Ⅰ期皮瓣感觉重建的研究

目的应用逆行皮神经营养血管筋膜蒂岛状皮瓣修复四肢肌腱、骨外露创面及皮瓣感觉重建。方法自1995年10月以来,应用该类型皮瓣修复手部创面20例,Ⅰ期邻近皮神经吻合皮瓣感觉重建10例,皮瓣面积最大17cm×12cm,最小8cm×7cm,蒂长2~5cm,宽4~5cm。修复膝、小腿及足部创面32例,皮瓣面积最大26·5cm×9cm,最小10cm×6cm,蒂长7~12cm,宽3~6cm。Ⅰ期邻近皮神经吻合皮瓣感觉重建12例。结果术后皮瓣完全成活48例,边缘部分坏死2例,完全坏死2例。经过3个月至2年的随访表明皮瓣感觉重建病例组感觉恢复S29例,S313例,较未吻合皮神经组的皮肤感觉有明显的差别。结论逆行皮神经营养血管筋膜蒂岛状皮血供可靠,不损伤肢体主要动脉。皮瓣所携带的皮神经与临近神经吻合可同时重建手掌及足底等重要部位的感觉功能,可作为四肢创伤皮肤缺损骨外露修复的首选皮瓣。     

三种方法治疗肩周炎90例疗效比较

目的 比较肩周炎患者采用三种不同治疗方法的疗效。方法 选择90例肩周炎患者，随机分为三组，每组30例，各组条件基本一致，采用三种不同方法，进行疗效比较。A组口服消炎镇痛药芬必得每次0．6g，每日2次，通经活血药盘龙七每次0．6g，每日3次，10d为1个疗程；汽化药热疗，每日1次，10d为1个疗程。功能锻炼，每日数次。B组肩胛上神经阻滞（1％利多卡因10ml＋醋酸强的松龙25mg＋维生素B1 100mg＋维生素B12 500μg），口服盘龙七＋汽化药热疗＋功能锻炼。C组肌间沟臂丛神经阻滞（1％利多卡因10m1），待阻滞完善后行手法松解肩关节的粘连，松解粘连后采用痛点阻滞（2％利多卡因2ml＋醋酸强的松龙25mg＋维生素B1 100mg＋维生素B12 500μg），口服盘龙七＋功能锻炼。结果 三组治愈率：A组13％，B组66％，C组93％。C组明显优于A、B组（P〈0．05）。结论 综合疗法是治疗肩周炎较理想的治疗方法。