Parieto-Occipital Interhemispheric Transfalcine, Trans-Bitentorial Approach for Radical Resection of Falcotentorial Meningiomas

Abstract

Objective Falcotentorial meningioma occurs close to the falcotentorial edges and the confluence of the vein of Galen. The posterosuperior approach conventionally used to reach this site does not allow direct visualization of the tumor matrix, making detachment difficult. Meningiomas at this location are therefore among those that are not well amenable to radical resection. We devised an alternative anterolateral approach that, when used in addition to the posterosuperior approach, provides an operating field which allows to overview large, bilaterally extending tumors. We report this parieto-occipital interhemispheric transfalcine, trans-bitentorial approach, together with associated procedural modifications. Methods We used the approach in four patients with falcotentorial meningioma between February 2008 and July 2017. We began by extending a parieto-occipital craniotomy slightly beyond the midline, to pass across the most caudal bridging vein on the rostral side. We then created a fan-shaped fenestration as large as possible in the falx, between the superior sagittal sinus and the inferior sagittal and straight sinuses (window 1). We further performed wedge-shaped resections of both tentorial edges to the left and right of window 1 (windows 2 and 3). Tumor debulking was then carried out via these three windows (the triple-window method). Finally, we detached the tumor in the area of the falcotentorial edges and the confluence of the vein of Galen. To obtain a superorostral operating field as wide as possible from laterally, thereby exposing the potential blind spots, the operating surgeon used both hands while retracting the precuneus, and the assistant surgeon used both hands to turn over the falcotentorial edges (twosome four-hand retractorless microsurgery). Results The wide operating field provided by this parieto-occipital interhemispheric transfalcine, trans-bitentorial approach and twosome four-hand retractorless microsurgery provides a direct view of delicate structures at the falcotentorial edges and the confluence of the vein of Galen, a site that is most likely to be a blind spot in conventional approaches. Retraction of the precuneus on the nondominant side enabled radical resection with no neurologic deficit in any of the patients. Conclusions The parieto-occipital interhemispheric transfalcine, trans-bitentorial approach with the triple-window method opens an anterolateral operating field in addition to a posterosuperior operating field in large tumors located in the falcotentorial and pineal region, extending anteroposteriorly and bilaterally. The twosome four-hand retractorless technique via this approach enables visualization of the tumor matrix at sites, which are barely visible with the conventional approach. Thus, the tumor can be removed more radically and safely.

Combined supracerebellar infratentorial and right occipital interhemispheric approach to falcotentorial junction meningioma: A case report

“…However, this approach is related to precuneus retraction and visual impairments. [15] e occipital transtentorial/transfalcine corridor is recommended by Nowak et al for its minimal risk of air embolism, good internal cerebral vein, and midbrain anatomy visibility. [14] e supratentorial and infratentorial regions are both exposed by the occipital transtentorial/transfalcine approach and its modifications.…”

Combined Microscopic and Endoscopic Surgery for Pineal Region Meningiomas Using the Occipital-Parietal Transtentorial Approach

“…This approach allows poor visualization of the ventral aspect of the vein of Galen, contralateral basal vein, and contralateral quadrigeminal region (Figure 2A). A transfalcine approach has been reported to improve exposure of the contralateral operative field through additional incisions above the sagittal sinus in the falx, but it is associated with significant risks (20). Meningiomas in the pineal region often compress the vital deep venous systems and develop collateral venous channels in the falx and tentorium.…”

Falcotentorial Meningiomas: Optimal Surgical Planning and Intraoperative Challenges - Case Report and a Review

“…Homonymous hemianopia is the most frequent postoperative deficit. 16 In addition, transient deficits related to the deviation from the conjugated gaze (Parinaud syndrome) and diplopia, being justified by manipulation during the resection of the structure of the dorsal midbrain, such as the collicular plate. This deficit is mostly reversible a few days after the surgery, especially if the arachnoid plan is respected.…”

“…Permanent cortical amaurosis has been described as a possible surgical complication related to prolonged occipital lobe retraction time. 16 Hemiparesis, hemidysesthesia, tetraparesis, neglectsyndrome, and postoperative intraventricular hemorrhage were described in the literature. 16,43 Our patient developed superior temporal homonymous quadrantanopia in the immediate postoperative period, permanently, without other neurological symptoms.…”