Departament of Neurosurgery, Instituto de Neurologia de Curitiba, Rua Jeremias Maciel Perretto 300, Curitiba, Paraná, Brazil.
Acta Neurochir (Wien). 2010 May;152(5):905-10. doi: 10.1007/s00701-009-0553-5. Epub 2009 Nov 10.
The suboccipital lateral or retrosigmoid approach is the main neurosurgical approach to the cerebellopontine angle (CPA). It is mainly used in the treatment of CPA tumors and vascular decompression of cranial nerves. A prospective study using navigation registered with anatomical landmarks in order to identify the transverse and sigmoid sinuses junction (TSSJ) was carried out in a series of 30 retrosigmoid craniotomies. The goal of this study was to determine the accuracy of this navigation technique and to establish the relationship between the location of the asterion and the TSSJ.
From March through November 2008, 30 patients underwent a retrosigmoid craniotomy for removal of CPA tumors or for surgical treatment of neurovascular syndromes. Magnetic resonance imaging (MRI) T1 sequences with gadolinium (FSPGR with FatSst, 1.5 T GE Signa) and frameless navigation (Vector vision, Brainlab) were used for surgical planning. Registration was performed using six anatomical landmarks. The position of the TSSJ indicated by navigation was the landmark to guide the craniotomy. The location of the asterion was compared with the position of the TSSJ. After craniotomy, the real TSSJ position was compared with the virtual position, as demonstrated by navigation.
There were 19 cases of vestibular schwannomas, 5 petroclival meningiomas, 3 trigeminal neuralgias, 1 angioblastoma, 1 epidermoid cyst and 1 hemifacial spasm. In all cases, navigation enabled the location of the TSSJ and the emissary vein, with an accuracy flaw below 2 mm. The asterion was located directly over the TSSJ in only seven cases. One patient had a laceration of the sigmoid sinus during the craniotomy.
Navigation using anatomical landmarks for registration is a reliable method in the localization of the TSSJ for retrosigmoid craniotomies and thereby avoiding unnecessary sinus exposure. In addition, the method proved to be fast and accurate. The asterion was found to be a less accurate landmark for the localization of the TSSJ using navigation.
枕下外侧或乙状窦后入路是小脑脑桥角（CPA）的主要神经外科入路。它主要用于治疗 CPA 肿瘤和颅神经的血管减压。本研究前瞻性地使用解剖标志注册导航，以确定横窦和乙状窦交界处（TSSJ），对 30 例乙状窦后颅切开术进行了一系列研究。本研究的目的是确定该导航技术的准确性，并确定星点的位置与 TSSJ 之间的关系。
2008 年 3 月至 11 月，30 例患者行乙状窦后颅切开术切除 CPA 肿瘤或手术治疗神经血管综合征。手术计划采用磁共振成像（MRI）T1 序列钆增强（FSPGR 加 FatSst，1.5 T GE Signa）和无框架导航（Vector vision，Brainlab）。注册使用六个解剖标志。导航指示的 TSSJ 位置是指导颅切开术的标志。比较星点的位置与 TSSJ 的位置。开颅后，通过导航比较真实 TSSJ 位置与虚拟位置。
19 例听神经瘤，5 例岩斜脑膜瘤，3 例三叉神经痛，1 例血管母细胞瘤，1 例表皮样囊肿，1 例面肌痉挛。在所有病例中，导航都能准确定位 TSSJ 和导静脉，误差小于 2 毫米。只有 7 例星点位于 TSSJ 正上方。1 例患者在开颅过程中出现乙状窦撕裂。
使用解剖标志注册导航是乙状窦后颅切开术中定位 TSSJ 的一种可靠方法，可以避免不必要的窦暴露。此外，该方法快速准确。研究表明，导航时星点对于 TSSJ 的定位不太准确。
