Various patterns of the middle cerebral vein and preservation of venous drainage during the anterior transpetrosal approach

Abstract

T he superficial middle cerebral vein (SMCV) usually runs inferiorly and anteriorly along the sylvian fissure and leads into the sphenoparietal sinus or directly into the cavernous sinus (CS). 3,5,13,25,27 Hacker classified the SMCV drainage pattern into 4 types: 1) sphenoparietal sinus, 2) sphenobasal vein (SBV), 3) sphenopetrosal vein, and 4) cortical veins with the absence of a definite SMCV. 9The anterior transpetrosal approach (ATPA) is best suited for upper petroclival lesions located anterior and superior to the internal auditory canal and superior to the inferior petrosal sinus.15,16 Epidural procedures and dural incision of the middle temporal fossa in ATPA may interrupt drainage routes from the SMCV.It has been demonstrated that surgical interruption of the SMCV leads to temporal lobe damage. obJective 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. methods 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. results 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. coNclusioNs The authors propose an SMCV modified classification based on ATPA modifications required for venous preservation.

The Analysis of the Petrosal Vein to Prevent Venous Complications During the Anterior Transpetrosal Approach in the Resection of Petroclival Meningioma

“…The CT-DSV scans were evaluated by the same neurosurgeon twice. This CT-DSV technique was almost the same that described in previous reports from our facilities 7,15 .…”

“…The surgical technique in our facility has been described in the several reports 4,6,7,13,14 . During the ATPA, the SPS was usually cut at the anterior and posterior sides.…”

“…The importance of knowledge of the venous anatomy for the safe performance of the ATPA has also been emphasized in some reports from the other facilities 2,[8][9][10] . However, these past venous studies, which employed the petrosal approach, focused on the SMCV, the vein of Labbe, SPS, and the bridging veins of the temporal lobe, [7][8][9]11,12 and less focused on the petrosal veins 2,10 .…”

“…Over the past two decades, we have experienced some cases involving venous complications in PCM patients who underwent resection via the ATPA. Our facility has made it a mission to avoid venous complications during ATPA and recently reported a study concerning the preservation of the superficial middle cerebral vein M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT (SMCV) in patients with PCM 7 . The importance of knowledge of the venous anatomy for the safe performance of the ATPA has also been emphasized in some reports from the other facilities 2,[8][9][10] .…”

Editorial: Temporal lobe venous preservation

“…8 The authors evaluated the anatomical variations of the superficial middle cerebral vein (SMCV) and proposed several surgical modifications to preserve this venous drainage during ATPA. All patients underwent preoperative evaluation of the SMCV using 3D CT venography (CTV).…”