后颅窝神经根疾病再手术

目的 探讨后颅窝神经根疾病术后复发再手术的临床特点和再手术的处理原则.方法 回顾分析2000至2007年临床收治的术后复发的后颅窝神经根疾病病例14例,包括三叉神经痛5例,面肌痉挛5例,舌咽神经痛4例,总结其临床和再手术术中发现特点.结果 5例三叉神经痛患者术后复发者,微血管减压术(microvascular decompression,MVD)2例,疼痛复发部位与术前相同,3例三叉神经感觉根第2、3支切断术后患者均为同侧第一支复发,其中4例接受再次感觉根部分切断手术,术后疼痛消失,随访2～11年未复发.5例而肌痉挛患者,4例再次梳理术后症状部分改善,1例没有改善.4例舌咽神经痛术后复发患者,2例发现舌咽神经再生吻合,1例发现舌咽神经近侧断端和迷走神经粘连,还有1例术中未发现舌咽神经再生及粘连情况,再次手术探查,切断再生神经及相邻2支迷走神经纤维根丝,随访2～5年无复发.术区一般病理改变包括:小脑与岩骨脑膜粘连严重;新生血管丰富,极易出血;行MVD患者的神经与周围相关血管和术中放置的涤纶布等减压材料粘连紧密,无法分离,初次手术部位局部瘢痕粘连,失去正常解剖结构,明显增加再次手术操作风险.结论 三义神经痛和面肌痉挛术后复发病因不明,舌咽神经痛复发可能的原因为神经纤维再生吻合、粘连及临近迷走神经纤维交通支引起.三叉神经痛、舌咽神经痛术后复发再次行神经纤维切断疗效确切.面肌痉挛复发再次面神经梳理手术效果较差.     

Spontaneous defects between the mastoid and posterior cranial fossa

Conclusions Spontaneous defects between the mastoid and the posterior cranial fossa are exceedingly rare. Patients with these lesions may have a lower BMI compared to those with middle cranial fossa encephaloceles, but are otherwise demographically similar. This study recommends repair via a transtemporal approach to allow for examination of the entire posterior face of the temporal bone. Objective To describe cases of spontaneous posterior cranial fossa defects. Methods This study reviewed all cases of spontaneous posterior fossa defects presenting to a tertiary referral center over the last decade and described clinical presentation, imaging, operative findings, and outcomes. We also compared these lesions to those previously reported in the literature as well as the more common spontaneous encephaloceles of the middle cranial fossa.

Results This study identified five cases with a mean age of 61.4 years, female-to-male ratio of 4:1, and a mean BMI of 31. Three cases presented with spontaneous pneumocephalus, one with CSF otorrhea, and one as an incidental imaging finding. Four defects were found medial to the sigmoid sinus and one was in the lateral retrosigmoid air cells.     

An unusual posterior cranial fossa tumour causing hearing loss

Clivus meningioma is an uncommon tumour arising from the region of the synchrondrosis between the basal portions of the sphenoid and occipital bones. We report a case of a patient with a large meningioma of the clivus whose presenting symptom was auditory change. Alteration of hearing is a rare mode of presentation for such a tumour although it may present at a later stage in about 50 per cent of cases. The discrepancy between the size of the tumour and the paucity of physical findings, the value of a multiple test auditory screening strategy, and the surgical approach in this case are discussed.     

A morphological and morphometric study of the peripheral process of the human vestibular nerve following posterior cranial fossa neurectomy

Three vestibular nerve specimens removed at transmeatal neurectomy were studied in order to understand better retrograde degeneration and regeneration after vestibular neurectomy in the posterior cranial fossa. In two cases this procedure followed retrolabyrinthine retrosigmoid posterior fossa vestibular neurectomy. The subjects, three patients with Menière's disease, were compared with one another and two autopsy controls with no known otological problem. The specimens were obtained at the distal end of the internal auditory canal and transversely sectioned. Many collapsed Schwann cell basement membranes were observed. The ratio of small-diameter nerve fibres increased significantly after neurectomy. Onion bulb formation around myelinated nerve fibres with small diameters and Schwann cell proliferation around the soma of vestibular ganglion cells reflected remyelination. We conclude that peripheral processes of vestibular nerve fibres can undergo retrograde degeneration and subsequent regeneration after transection of the central process.     

中颅窝进路面神经探查减压术

自1991年以来，我们对5例具有明显手术指征的外伤性面瘫患者行中颅窝进路面神经探查减压术，取得了较满意的临床效果，报道如下。     

骑跨中后颅窝底肿瘤的显微外科治疗

目的：对15例骑跨中后颅窝底脑肿瘤的手术入路及治疗经验进行总结。方法：骑跨中后颅窝底脑肿瘤15例，包括颅咽管瘤6例，脑膜瘤5例，神经鞘瘤3例，垂体瘤1例，均采用改良翼点入路。其中11例采用硬脑膜内入路，4例采用硬脑膜外入路切除。结果：肿瘤全切除12例，次全切3例，无手术死亡。结论：改良翼点入路是切除骑跨中后颅窝底肿瘤的理想入路之一。结合各类肿瘤的临床特点及其与邻近结构、生长方向的关系，选择合适的手术入路并与显微神经外科技术有机地结合是取得最好疗效的关键。     

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。     

The value of the examination of visuooculomotor reflexes in diagnosis of posterior cranial fossa lesions

The aim of this study was to compare the frequency of pathological types of smooth-pursuit and saccadic movements in different localizations of vestibular lesions. We tested 112 patients using videonystagmography. The smooth pursuit was appreciated qualitatively on the basis of Malecki's patterns. We analyzed the saccadic movements taking three parameters into consideration: latency, velocity, and accuracy. The patients suffered from posterior cranial fossa lesions, supratentorial damage, and peripheral vestibular disorders. We discovered that testing of smooth pursuit and saccades was very helpful in pointing to the localization of the damage in the posterior fossa. The frequency of the pathological saccadic and eye-tracking movements was similar for the different sites of deficit inside the posterior fossa, so recognizing the precise localization of lesion in this anatomical region was difficult.