The foramen ovale: a keyhole to the brain? Computer simulations of percutaneous FO punctures

Abstract

Abstract Background The percutaneous cannulation of the foramen ovale (FO) is implemented in treating trigeminal neuralgia, diagnosing temporal lobe epilepsy and biopsy petroclival lesions. This study dealt with the question whether it is possible to reach intracerebral structures with a puncture beyond the Gasserian Ganglion (GG) without bone destruction or perforating vascularity. Methods We considered the FO a natural keyhole and performed computer-simulated punctures through the right and left FO to eight intracerebral structures. Therefore, we took the Hartel and Submandibular (SM) approach as a starting point and planned trajectories with stereotactic planning software by using brain scans of ten patients. Results The simulated punctures with the Hartel approach directly reached the hippocampus (20 out of 20 trajectories), the lateral ventricle (15/20) and the amygdala (2/20). The pons was reached (20/20); however, the pontine vascularity was within the course. The trajectories to the thalamus (13/20) ran through the hippocampus or the mesencephalon. The simulated punctures with the SM approach directly reached the amygdala (18/20), the lateral ventricle (5/20) and the putamen (20/20). The trajectories to the nucleus caudatus (20/20) pierced the hippocampus, the putamen or the maxillary artery. The courses to the thalamus (7/20) ran through the hippocampus or the mesencephalon. The sinus cavernosus could not be reached with the Hartel or SM approach. Conclusions This study indicates that a percutaneous approach to the hippocampus, the lateral ventricle, the amygdala and the putamen is possible without harming major vessels or bone destruction. For a possible implementation of these trajectories in a clinical setting, it is necessary to prove these simulated punctures in cadaveric studies.