Background: For the anterior inferior cerebellar artery (AICA), and posterior inferior cerebellar artery (PICA), there are proven bypasses for the distal segment of each artery. However, the proximal bypass of AICA requires a distinctive approach. It is quite challenging because 1) it is not simple to reach the proximal segment, 2) the availability and the accessibility of the proper vessels from the donor, and 3) the plan that will be executed either in the form of trapping in case of a fusiform aneurysm or redirection of the flow by bypass. Currently, no reported approach allows for the proximal anastomosis of the proximal AICA.
Objective: To investigate, for the first time, the occipital artery (OA)-AICA bypass through the presigmoid transtentorial retrolabyrinthine approach in cadaveric models with a focus on exposure evaluation and surgical feasibility.
Methods: Five adults injected cadaveric heads and were operated on both sides, performing a total of 10 surgical dissections—the measurement of the recipient artery's depth and the donor's length. Surgical feasibility was assessed. The surgical approach was performed in a stepwise manner. Pre- and post-procedural cranial CT images were used to obtain measurements.
Results: OA that was obtained in the bypass is through following the landmark of the mastoid notch, and we move proximal and distal to it. The OA graft is usually measured from 8 cm to 12 cm. Extra centimeters may be attained, particularly when the trapping method is needed to be performed. Then a presigmoid transtentorial (supra-infra-tentorial) retrolabyrinthine approach was performed. The proximal premeatal AICA was dissected and prepared for the bypass. Comparisons with other available approaches were provided as well.
Conclusion: OA-proximal AICA bypass is applicable through a presigmoid retro-labyrinthine transtentorial approach in terms of exposure and surgical feasibility.