Department of Neurological Surgery, NewYork-Presbyterian Hospital, Weill Cornell Medical College, New York, New York.
Department of Neurosurgery, Stanford University School of Medicine, Stanford, California.
J Neurosurg. 2017 Nov;127(5):1139-1146. doi: 10.3171/2016.9.JNS161503. Epub 2017 Jan 13.
OBJECTIVE Sporadic cases of endonasal intraaxial brainstem surgery have been reported in the recent literature. The authors endeavored to assess the feasibility and limitations of endonasal endoscopic surgery for approaching lesions in the ventral portion of the brainstem. METHODS Five human cadaveric heads were used to assess the anatomy and to record various measurements. Extended transsphenoidal and transclival approaches were performed. After exposing the brainstem, white matter dissection was attempted through this endoscopic window, and additional key measurements were taken. RESULTS The rostral exposure of the brainstem was limited by the sella. The lateral limits of the exposure were the intracavernous carotid arteries at the level of the sellar floor, the intrapetrous carotid arteries at the level of the petrous apex, and the inferior petrosal sinuses toward the basion. Caudal extension necessitated partial resection of the anterior C-1 arch and the odontoid process. The midline pons and medulla were exposed in all specimens. Trigeminal nerves were barely visible without the use of angled endoscopes. Access to the peritrigeminal safe zone for gaining entry into the brainstem is medially limited by the pyramidal tract, with a mean lateral pyramidal distance (LPD) of 4.8 ± 0.8 mm. The mean interpyramidal distance was 3.6 ± 0.5 mm, and it progressively decreased toward the pontomedullary junction. The corticospinal tracts (CSTs) coursed from deep to superficial in a craniocaudal direction. The small caliber of the medulla with very superficial CSTs left no room for a safe ventral dissection. The mean pontobasilar midline index averaged at 0.44 ± 0.1. CONCLUSIONS Endoscopic endonasal approaches are best suited for pontine intraaxial tumors when they are close to the midline and strictly anterior to the CST, or for exophytic lesions. Approaching the medulla is anatomically feasible, but the superficiality of the eloquent tracts and interposed nerves limit the safe entry zones. Pituitary transposition after sellar opening is necessary to access the mesencephalon.
最近的文献中报道了一些经鼻腔颅内脑桥手术的散发病例。作者旨在评估经鼻内镜手术入路治疗脑桥腹侧病变的可行性和局限性。
使用 5 个人体头颅标本评估解剖结构并记录各种测量值。进行了扩展经蝶窦和经颅底入路。暴露脑桥后，尝试通过这个内镜窗口进行白质解剖，并进行了额外的关键测量。
脑桥的颅侧暴露受限于鞍底。暴露的外侧界限是鞍底水平的海绵窦内颈动脉、岩尖水平的颅底内颈动脉和靠近颅底的岩下窦。向尾侧延伸需要部分切除前 C1 弓和齿状突。所有标本均暴露中脑桥和延髓的中线。不使用角度内镜，三叉神经几乎不可见。进入脑桥的peri-trigeminal 安全区的通道在内侧受锥体束限制，平均侧锥体束距离（LPD）为 4.8 ± 0.8mm。平均锥体束间距离为 3.6 ± 0.5mm，在桥延交界处逐渐减小。皮质脊髓束（CSTs）从颅底向颅顶方向在深层到浅层方向走行。延髓的小口径和非常浅表的 CSTs 没有为安全的腹侧解剖留下空间。平均桥基底中线指数平均为 0.44 ± 0.1。
当肿瘤靠近中线且严格位于 CST 之前，或为外生性病变时，内镜经鼻入路最适合治疗脑桥的轴内肿瘤。到达延髓在解剖上是可行的，但神经束和神经的表浅性限制了安全进入区。鞍底打开后进行垂体移位是进入中脑的必要条件。
