Shibao Shunsuke, Toda Masahiro, Orii Maaya, Fujiwara Hirokazu, Yoshida Kazunari
Department of Neurosurgery, Keio University School of Medicine; and.
Department of Diagnostic Radiology, Keio University Graduate School of Medicine, Tokyo, Japan.
J Neurosurg. 2016 Feb;124(2):432-9. doi: 10.3171/2015.1.JNS141854. Epub 2015 Aug 28.
The drainage of the superficial middle cerebral vein (SMCV) has previously been classified into 4 subtypes. Extradural procedures and dural incisions during the anterior transpetrosal approach (ATPA) may interrupt the route of drainage from the SMCV. In this study, the authors examined the relationship between anatomical variations in the SMCV and the corresponding surgical modifications to the ATPA that are necessary for venous preservation.
This study included 48 patients treated via the ATPA in whom the SMCV was examined using 3D CT venography. The drainage patterns of the SMCV were classified into 3 types: cavernous or absent (Type 1), sphenobasal (Type 2), and sphenopetrosal (Type 3). Type 2 was subdivided into medial (Type 2a) and lateral (Type 2b), and Type 3 was subdivided into vein (Type 3a), vein and sinus (Type 3b), and sinus (Type 3c). The authors performed 3 ATPA modifications to preserve the SMCV: epidural anterior petrosectomy with subdural visualization of the sphenobasal vein (SBV), modification of the dural incision, and subdural anterior petrosectomy. Standard ATPA can be performed with Type 1, Type 2a, and Type 3a drainage. With Type 2b drainage, an epidural anterior petrosectomy with subdural SBV visualization is appropriate. The dural incision should be modified in Type 3b. With Type 3c, a subdural anterior petrosectomy is required.
The frequency of each type was 68.7% (33/48) in Type 1, 8.3% (4/48) in Type 2a, 4.2% (2/48) in Type 2b, 14.6% (7/48) in Type 3a, 2.1% (1/48) in Type 3b, and 2.1% (1/48) in Type 3c. No venous complications were found.
The authors propose an SMCV modified classification based on ATPA modifications required for venous preservation.
大脑中浅静脉（SMCV）的引流先前已被分为4种亚型。经岩骨前入路（ATPA）期间的硬膜外手术和硬脑膜切开可能会中断SMCV的引流途径。在本研究中，作者研究了SMCV的解剖变异与为保留静脉而对ATPA进行的相应手术改良之间的关系。
本研究纳入了48例接受ATPA治疗的患者，术中使用三维CT静脉造影检查SMCV。SMCV的引流模式分为3种类型：海绵窦型或无引流型（1型）、蝶骨基底型（2型）和蝶骨岩骨型（3型）。2型又细分为内侧型（2a型）和外侧型（2b型），3型又细分为静脉型（3a型）、静脉窦型（3b型）和窦型（3c型）。作者进行了3种ATPA改良以保留SMCV：硬膜外岩骨前切除术并在硬膜下显露蝶骨基底静脉（SBV）、硬脑膜切口改良以及硬膜下岩骨前切除术。1型、2a型和3a型引流可采用标准ATPA。2b型引流时，硬膜外岩骨前切除术并在硬膜下显露SBV是合适的。3b型需改良硬脑膜切口。3c型则需要进行硬膜下岩骨前切除术。
各类型的发生率分别为：1型68.7%（33/48）、2a型8.3%（4/48）、2b型4.2%（2/48）、3a型14.6%（7/48）、3b型2.1%（1/48）、3c型2.1%（1/48）。未发现静脉并发症。
作者基于保留静脉所需的ATPA改良提出了一种SMCV改良分类法。
