Tayebi Meybodi Ali, Gandhi Sirin, Mascitelli Justin, Bozkurt Baran, Bot Gyang, Preul Mark C, Lawton Michael T
J Neurosurg. 2018 Jun 29;130(5):1426-1434. doi: 10.3171/2018.1.JNS173139. Print 2019 May 1.
Access to the ventrolateral pontomesencephalic area may be required for resecting cavernous malformations, performing revascularization of the upper posterior circulation, and treating vascular lesions such as aneurysms. However, such access is challenging because of nearby eloquent structures. Commonly used corridors to this surgical area include the optico-carotid, supracarotid, and carotid-oculomotor triangles. However, the window lateral to the oculomotor nerve can also be used and has not been studied. The authors describe the anatomical window formed between the oculomotor nerve and the medial tentorial edge (the oculomotor-tentorial triangle [OTT]) to the ventrolateral pontomesencephalic area, and assess techniques to expand it.
Four cadaveric heads (8 sides) underwent orbitozygomatic craniotomy. The OTT was exposed via a pretemporal approach. The contents of the OTT were determined and their anatomical features were recorded. Also, dimensions of the brainstem surface exposed lateral and inferior to the oculomotor nerve were measured. Measurements were repeated after completing a transcavernous approach (TcA), and after resection of temporal lobe uncus (UnR).
The s1 segment and proximal s2 segment of the superior cerebellar artery (SCA) and P2A segment of the posterior cerebral artery (PCA) were the main contents of the OTT, with average exposed lengths of 6.4 ± 1.3 mm and 5.5 ± 1.6 mm for the SCA and PCA, respectively. The exposed length of the SCA increased to 9.6 ± 2.7 mm after TcA (p = 0.002), and reached 11.6 ± 2.4 mm following UnR (p = 0.004). The exposed PCA length increased to 6.2 ± 1.6 mm after TcA (p = 0.04), and reached 10.4 ± 1.8 mm following UnR (p < 0.001). The brainstem surface was exposed 7.1 ± 0.5 mm inferior and 5.6 ± 0.9 mm lateral to the oculomotor nerve initially. The exposure inferior to the oculomotor nerve increased to 9.3 ± 1.7 mm after TcA (p = 0.003), and to 9.9 ± 2.5 mm after UnR (p = 0.21). The exposure lateral to the oculomotor nerve increased to 8.0 ± 1.7 mm after TcA (p = 0.001), and to 10.4 ± 2.4 mm after UnR (p = 0.002).
The OTT is an anatomical window that provides generous access to the upper ventrolateral pontomesencephalic area, s1- and s2-SCA, and P2A-PCA. This window may be efficiently used to address various pathologies in the region and is considerably expandable by TcA and/or UnR.
切除海绵状血管畸形、对上后循环进行血管重建以及治疗动脉瘤等血管病变时，可能需要进入脑桥中脑腹外侧区域。然而，由于附近存在功能明确的结构，这种进入具有挑战性。通往该手术区域常用的通道包括视神经 - 颈动脉三角、颈动脉上三角和颈动脉 - 动眼神经三角。然而，动眼神经外侧的窗口也可使用，且尚未得到研究。作者描述了动眼神经与小脑幕内侧缘之间形成的通向脑桥中脑腹外侧区域的解剖窗口（动眼神经 - 小脑幕三角[OTT]），并评估扩大该窗口的技术。
对4个尸头（8侧）进行眶颧开颅术。通过颞前入路暴露OTT。确定OTT的内容物并记录其解剖特征。此外，测量动眼神经外侧和下方暴露的脑干表面尺寸。在完成经海绵窦入路（TcA）后以及切除颞叶钩回（UnR）后重复测量。
小脑上动脉（SCA）的s1段和近端s2段以及大脑后动脉（PCA）的P2A段是OTT的主要内容物，SCA和PCA的平均暴露长度分别为6.4±1.3mm和5.5±1.6mm。TcA后SCA的暴露长度增加到9.6±2.7mm（p = 0.002），UnR后达到11.6±2.4mm（p = 0.004）。TcA后PCA的暴露长度增加到6.2±1.6mm（p = 0.04），UnR后达到10.4±1.8mm（p < 0.001）。最初，在动眼神经下方7.1±0.5mm和外侧5.6±0.9mm处暴露脑干表面。动眼神经下方的暴露在TcA后增加到9.3±1.7mm（p = 0.003），UnR后增加到9.9±2.5mm（p = 0.21）。动眼神经外侧的暴露在TcA后增加到8.0±1.7mm（p = 0.001），UnR后增加到10.4±2.4mm（p = 0.002）。
OTT是一个解剖窗口，可提供通向脑桥中脑腹外侧上部区域、SCA的s1和s2段以及PCA的P2A段的宽敞通道。该窗口可有效用于处理该区域的各种病变，并且通过TcA和/或UnR可显著扩大。
