2025 Proffered Presentations
S353: THE C2-P2 BYPASS: TECHNICAL ASSESSMENT OF PETROUS CAROTID ARTERY TO POSTERIOR CEREBRAL ARTERY INTERPOSITIONAL BYPASS THROUGH THE COMBINED TRANSCOCHLEAR-SUBTEMPORAL APPROACH AS A PART OF MICROSURGICAL TREATMENT FOR DOLICHOECTATIC VERTEBROBASILAR ARTERY ANE
Ali Tayebi Meybodi, MD; Andrea L Castillo, MD; Gerardo Gomez-Castro; Michael T Lawton, Md; Mark C Preul, MD; Barrow Neurological Institute
Background and Objectives: Managing dolichoectatic vertebrobasilar artery aneurysms (DVBA) requires a multifaceted approach. Revascularization of the posterior circulation with a high-flow bypass is part of the flow reversal paradigm. Performing a robust high-flow bypass and addressing the aneurysm through the same approach smoothen the operative intervention. We assessed the anatomic feasibility of accessing the basilar trunk/aneurysm and simultaneously revascularizing the posterior circulation using a petrous internal carotid artery (pICA)–posterior cerebral artery (PCA) interpositional bypass via a complete petrosectomy.
Methods: Six embalmed cadaveric heads (12 sides) underwent a combined extended transcochlear-subtemporal approach to expose the pICA and P2 PCA. A pICA (S-E) graft (E-S) PCA bypass was attempted. The lengths of the vessels relevant to the bypass and the graft length were measured.
Results: The bypass was completed in all specimens. The mean exposed lengths of the pICA and PCA were 21.3 mm and 20.0 mm, respectively. The mean length of the perforator-free zone on PCA was 11.2 mm. The mean length of the interposition graft was 36.6 mm.
Conclusion: The transcochlear approach can be used to expose the pICA as a donor for a high-flow bypass to the PCA as part of the treatment paradigm for DVBAs. Careful patient selection and extensive knowledge of skull base anatomy are mandatory for this strategy.
Figure 1.
Outlines of skin incision and skull base approaches. The dashed line shows the skin incision for the combined transcochlear-subtemporal approach. The anterior limit for skin incision and craniotomy is approximately at the sphenosquamosal suture. The anterior limit for the skin incision and craniotomy is approximately at the coronal level of EAC. The green region shows the area of the mastoidectomy. The yellow region shows the subtemporal approach area. Abbreviations: EAC, external auditory canal; SNL, superior nuchal line.
Figure 2.
Stepwise illustration of a cadaveric prosection of the combined transcochlear-subtemporal approach.
Figure 3.
Artist’s illustration of the surgical exposure of the DVBA and ICA-PCA interpositional bypass through the combined transcochlear-subtemporal approach.