迷路后进路内镜手术中内耳道的定位

目的：为迷路后进路处理桥脑小脑角区及内耳门区病变手术中内耳道的定位提供参考依据。方法：4％多聚甲醛固定的成人头颅标本（正常完整颅底）15例（30侧,性别不限）,模拟迷路后进路操作,沿外半规管平面导入0°2．7mm耳内镜,观察内耳道与外半规管的关系。结果：内耳道口中心与外半规管平面一致,面听神经束的走行（内耳道走行）与外半规管平面的关系：①面听神经起始部位于外半规管平面之下者2侧（6．7％）;②面听神经起始部位于外半规管平面者15侧（50．0％）;③面听神经起始部位于外半规管平面之上者13侧（43．3％）。结论：在迷路后进路桥脑小脑角区及内耳道手术中,以外半规管定位内耳道具有直接、准确、对周围组织损伤小的优点,更符合微创外科手术的要求。     

高分辨率CT颅中窝径路定位内耳道的解剖研究

目的 研究术前高分辨率CT (high resolution computerized tomography,HRCT)个体化测量,利用颧弓根、棘孔与锤骨头三者的距离关系经颅中窝径路定位内耳道及面神经的可行性.方法18例福尔马林固定的成人颞骨标本,分为A组10耳,B组8耳,常规行HRCT扫描后进行测量.A组行颅中窝径路手术,比较各解剖实测值与CT测量值之间的关系,建立CT数据模型.B组行颅中窝径路手术时在CT测量值辅助下以颧弓根、棘孔及锤骨头为标志物寻找内耳道.采用配对t检验分析两种方法在各解剖结构测量结果间的差异,以P＜0.05为差异有统计学意义.结果 A组中锤骨头与周围重要解剖结构距离的CT测量值与解剖实测值间结果差异无统计学意义(P值均＞0.05).在HRCT辅助下行颅中窝手术时,B组利用颧弓根到锤骨头及棘孔到锤骨头的CT测量距离指导手术,在1.5～3.7 mm范围内均可正确定位锤骨头;8耳中除1耳其内耳道-锤骨头连线与颧弓根-锤骨头参考线夹角为15°,余7耳颧弓根、锤骨头、内耳道均位于一条直线上.结论 颞骨HRCT可以较为真实地反映锤骨头与颧弓根、棘孔、内耳道等解剖结构之间的距离关系.在行颅中窝手术时,可以借助HRCT通过颧弓根及棘孔来定位锤骨头,进而在其他解剖标志点不清时利用锤骨头安全地定位内耳道.     

人内耳迷路的内分泌细胞

苏联研究者发现内耳具有一种与激素代谢有关的 anyg 细胞,于血管纹、球囊、椭圆囊及半规管等处可见到,认为与三种活性物质—5-羟色胺、褪黑素和去甲肾上腺素的分泌有关。(编者)     

迷路下入路开放内耳道手术相关解剖结构的CT测量

目的　为临床上开展迷路下入路开放内耳道手术提供影像学参考信息。方法　选择40例（80侧）正常成人颞骨CT影像资料,对迷路下入路开放内耳道手术的相关解剖标志进行影像学测量。结果　后半规管下端到颈静脉球顶端之间的最短距离平均值为左侧（4.69±2.91）mm,右侧（3.10±3.01）mm,后半规管下部骨质厚度平均值左 侧（0.92±0.37）mm,右侧（0.69±0.37）mm,迷路下区面神经垂直段骨管和乙状窦骨板之间的最短距离平均值左侧（8.66±2.71）mm,右侧（7.74±1.99）mm,颈静脉球顶端到内耳道下界距离平均值左侧（6.32±2.88）mm,右侧（5.39±2.61）mm,颈静脉球顶端到单孔距离平均值左侧（6.82±3.02）mm,右侧（5.84±2.82）mm,前庭导水管开口到内耳门后缘的距离平均值为左侧（14.38±2.56）mm,右侧（14.12±2.76）mm,前庭导水管开口到内耳道中点的距离平均值为左侧（12.02±2.46）mm,右侧（11.91±2.53）mm。前3组测量值左右侧差异有统计学意义,后4组测量值左右侧差异无统计学意义。结论　术前行影像学测量能够为开展 迷路下入路开放内耳道手术提供有价值的信息。     

豚鼠内耳微循环障碍对血迷路屏障通透性的影响

OBJECTIVE: To study the changes of blood-labyrinth barrier permeability during cochlea microcirculatory disorders in guinea pigs. METHODS: Using modified method of Evan's blue fluorescence, the changes of permeability of blood-labyrinth barrier were observed in the animal model of cochlea microcirculatory disorders which was induced by photochemical reaction. RESULTS: Amount of Evan's blue passing through the blood-labyrinth barrier was (1.709 +/- 0.769) microgram per guinea pig after 2 hours and (2.849 +/- 0.653) microgram per guinea pig after 4 hours when the cochlea was in microcirculatory disorder. CONCLUSION: The results indicated that the permeability of blood-labyrinth barrier increased when cochlea microcirculatory disorders occurred and the increase of blood-labyrinth barrier permeability may be one of the important mechanisms which causes the cochlear ischemic lesions.     

颅中窝径路内耳道定位的放射解剖学研究

颅中窝径路内耳道 ( IAC)手术的关键是准确定位 IAC。然而 IAC隐蔽而狭小 ,道内及毗邻结构复杂而繁多 ,因此往往很难定位。本文的目的在于借助 CT这种特殊的检查手段 ,寻找一种准确、可靠、安全、简便易用、副损伤小的颅中窝径路的 IAC定位方法 ,从而为临床耳神经外科提供理论依据。1　材料和方法2 0例成人干燥颅骨标本 ,其中男 1 6例 ,女 4例 ,颅骨标本均完整无损。参照 CT龙门架上的立体定位系统将标本放入颅骨固定器中 ,固定于仰卧位 ,用 SCT-4 80 0 T/E型 CT机 ,按眶耳线扫描 ,扫描参数为矩阵 2 50×2 50 ,龙门架保持 0°角 (…     

内耳的显微解剖及临床应用

目的了解内耳及相邻结构的显微解剖,为术中切除岩骨骨质提供解剖学参数.方法在显微镜下对15例成人尸头标本的内耳及相邻结构进行解剖学测量.结果乙状窦沟、内听道孔、颈静脉孔、耳蜗、岩嵴和后半规管最后点等可作为手术标志.后半规管最后点和内听道孔后缘到乙状窦沟距离为9.8mm及22.0mm,岩骨后面到面神经管垂直部距离9.1mm,岩嵴到颈静脉球窝顶距离15.1mm,岩嵴最后点到耳蜗距离为28.6mm.结论熟练掌握内耳及相邻结构的解剖,严格限制骨质切除范围,就能既得到满意的手术暴露,又不引起更多并发症.     

豚鼠内耳微血管解剖结构的特点

为研究内耳微血管解剖结构的特点，应用微血管铸型技术，在扫描电镜下观察了１０只豚鼠基底膜、椭圆囊、球囊和三个壶腹的微血管三维空间构架。研究发现，无论在耳蜗或前庭，细动脉在到达供应部位以前均作螺旋状盘旋数周，延长了血管的长度，可维持内耳稳定的血液供应，并使内耳感受器不致受到血管搏动和血流噪声的影响。内耳微血管解剖的另一特点是，壶腹嵴半月面区的血管网较血管纹区稀疏，提示血管纹区的代谢比暗细胞区者旺盛；而基底膜中的微血管网较前庭区感觉上皮下方的血管网明显稀少，提示耳蜗毛细胞的能量需求较少，对缺氧的耐受力较强。     

改良迷路下入路开放内耳道解剖研究

目的　为改良迷路下入路开放内耳道手术提供解剖学参考。方法　在10例尸头标本（左右耳各10侧）上模拟改良迷路下入路开放内耳道手术,进行相关解剖测量和观察。结果　本实验有16侧（左右耳各8侧）经改良迷路下入路能开放内耳道后壁,平均暴露长度为内耳道后壁总长度（72.44±14.19）%,后半规管下端到颈静脉球顶端的距离平均值（4.60±3.47）mm,迷路下区面神经垂直段和乙状窦距离平均值（8.40±2.74）mm,颈静脉球顶端到内耳道距离平均值（5.88±2.88）mm,内淋巴囊上端到内耳道距离平均值（13.24±3.41）mm。结论　改良迷路下入路内耳道手术创伤小,但难度较大,选择合适病例,做好相关术前准备,是能安全有效完成该类手术的。     

内镜下迷路后入路小脑脑桥角及内耳门区手术的实验解剖

目的 测量比较内耳门后唇至乙状窦前、后缘的距离;迷路后间隙与乙状窦距外耳道后壁距离的相关性,为经迷路后入路内镜下小脑脑桥角区及内耳道微创手术提供解剖学依据.方法 10％甲醛固定的成人头颅标本（正常完整颅底）15例（30侧）,性别不限,乳突轮廓化,迷路骨骼化,乙状窦全程解剖.①测量内耳门后唇至乙状窦前、后缘的距离;②测量...     

Patulous internal auditory canal

OBJECTIVE: To investigate a rare anomaly of the internal auditory canal known as a patulous canal and its relationship to hearing impairment. METHODS: High-resolution computed tomographic scans of the temporal bones of patients who presented between August 2001 and August 2002 were reviewed. The patients' medical charts were evaluated for age, sex, and hearing impairment, and the computed tomographic scans were examined for the presence of a patulous canal. RESULTS: The study group included 645 patients who underwent high-resolution computed tomography of the temporal bones for various reasons, including sensorineural hearing loss (50% of patients). A patulous canal without any associated anomaly of the labyrinth was the only finding in 2 patients. Both patients had chronic middle ear disease along with conductive hearing loss. CONCLUSION: Patulous canal is a rare anatomical variant of the internal auditory canal (0.3%), and its association with inflammatory ear disease accompanied by conductive hearing impairment appears to have been incidental in both cases in the present study.     

Surgical exposure of the fundus of the internal auditory canal: Anatomic limits of the middle fossa versus the retrosigmoid transcanal approach

Objective: To define the anatomic limitations and advantages of the middle cranial fossa and the retrosigmoid transcanal approaches in the exposure of the fundus of the internal auditory canal (IAC). Study Design: A series of 15 cadaver temporal bone specimens were dissected and the measurements of the lateral recess of the IAC were made with a millimeter rule and rounded to the nearest quarter millimeter. Methods: Retrospective case review, surgical observation, review, and measurements recorded from magnetic resonance scans. Surgical observations and measurements recorded from cadaver specimens. Results: These results were compared with historical studies of the retrosigmoid transcanal approach. The results utilizing a combination of these approaches to remove acoustic neuromas at a tertiary referral center during the preceding 11 years are also presented. Previous studies have shown that for the retrosigmoid transcanal approach, it is impossible to expose 3 to 4 mm of the lateral recess of the IAC without violating the vestibule and/or the endolymphatic duct. This has led some authors to advocate the middle cranial fossa approach to the IAC when hearing preservation is a consideration. The current study shows that the falciform crest obscures the inferior half of the fundus. This creates a pocket that cannot be visualized, which on average is 1.82 × 2.33 mm. Conclusion: The fundus of the IAC cannot be completely exposed without violating the labyrinth through either the posterior fossa or middle fossa approach. The clinical implications of these studies are unknown at this time. Low recurrence rates are achieved with both approaches. The anatomic limitations of both approaches must still be considered when planning or performing these approaches, to minimize the risk of recurrence.     

Meningioma of the internal auditory canal

The great majority of tumors that arise in the internal auditory canal are schwannomas of the eighth cranial nerve (acoustic neuromas). Meningiomas constitute the second largest group of posterior fossa tumors. Meningiomas arise from arachnoid villae, the apparatus responsible for cerebrospinal fluid absorption, in proximity to a major vein or dural sinus in most cases. Arachnoid villae are also present along neural foramena at the base of the skull. They have been observed histologically in the internal auditory canal (IAC), and are the probable site of origin of meningiomas in this location. Larger cerebellopontine angle meningiomas occasionally possess a significant intracanalicular component; however, these lesions usually originate from the meningeal lining of the posterior petrous face adjacent to the sigmoid, superior petrosal, or inferior petrosal sinuses and prolapse into the IAC. Two meningiomas have recently been observed that extensively involved the IAC, one of which arose from the lining of the IAC. The clinical manifestations of these meningiomas mimicked those of acoustic neuromas. Preoperative radiographic studies, including magnetic resonance imaging, were unable to differentiate these from acoustic neuromas. Meningiomas have a higher rate of recurrence than acoustic neuromas and should be excised with surrounding dura and several millimeters of subjacent bone. Meningiomas that extensively involve the IAC have a tendency to invade the inner ear and the deeper portions of the temporal bone. In meningiomas that involve the lateral portion of the IAC, consideration should be given to exenteration of the cochlea and semicircular canals.