Objective: To study the microanatomy by endoscope-assisted via retrolabyrinthine approach.
Method: Nineteen cadaveric heads fixed with formalin were dissected in our study. The data that endoscope could be extent and the distance between the important point were measured. By simulated the retrolabyrinthine approach, endoscope was placed to observe the nerves and vessels, the distance between nerves and the central point of the anterior edge of sigmoid sinus were measured.
Result: The distance from the inferior margin of petrous ridge to the upper bound of endolymphatic sac was (9.93+/-1.52)mm; and from superior margin of petrous ridge to the inferior margin common bony crus was (4.64+/-0.91)mm;and from the intersection of posterior semicircular canal to the anterior wall of sigmoid was (7.85+/-1.47)mm on the left, and (5.69+/-1.68)mm on the right. The distance from inferior margin common bony crus to the anterior wall of sigmoid was (13.9+/-1.71)mm on the left, and (11.31+/-2.03)mm on the right. The trochlear nerve and abducent nerve could be observed under endoscope. The relationship between the trigeminal nerve, acoustic nerve and the vessels could be identified clearly. The distance from the central point of the anterior edge of sigmoid to the roots of the trigeminal nerve, facial nerve, vestibulocochlear nerve and glossopharyngeal nerve were (29.88+/-2.77) mm, (32.04+/-2.04) mm, (29.17+/-1.65) mm, (35.49+/-1.53) mm respectively.
Conclusion: The visual field of the cerebellopontine angle appear wider by the endoscope assisted retrolabyrinthine approach. Nerves, vessel, internal acoustic pore, jugular foramen region can be clearly seen. Some minimal invasive surgery can be done by this approach.