Petrous carotid artery's in situ bypass: anatomic study.

The purpose of our study was to reveal the possibility of cervical-to-petrous carotid artery in situ bypass with maximum preservation of cranial nerves. Four human cadavers prepared in formalin were investigated. Eight surgical approaches were used (bilateral exposure on each cadaver). The skin incision started from the level of the temporomandibular joint. The VII, IX, X, and XII cranial nerves, starting from the stylomastoid angle, were maximally preserved. Resection of the styloid process, subluxation of the mandibular joint, and milling of tympanic bone revealed the petrous carotid artery. Exposure of the carotid bifurcation was performed with a mini-skin incision. After dividing the petrous internal carotid artery (ICA) and the cervical ICA, the cervical ICA was dilated using a Fogarty catheter to simulate aneurysmal dilatation. The patient's saphenous vein after stripping was utilized for the bypass. The vein was passed into the lumen of the dilated cervical ICA, and a cervical-to-petrous carotid bypass was performed. In each case, the described technique made it possible to expose the intrapetrous carotid artery adequately. In two cases it was impossible to make a luxation, and therefore the mandibular branch was resected. The vertical segment's mean length was 12 mm (range 10-15 mm). In all cases, the VII, IX, X, and XII cranial nerves were preserved maximally. The main points of the approach are luxation of the mandibular articulation and milling of the tympanic bone. Our study in cadavers suggests the possibility of petrous carotid artery bypass without exposing the cervical ICA.