An endoscopic anatomy study of the cerebellopontine angle through retrolabyrinthine approach

Objective To study anatomic land marksers and orientation methodology in the cerebellopontine angle through retrolabyrinthine approach under an endoscope. Methods In 10 cadaveric specimens (20 sides),endoscopic surgery via retrolabyrinthine approach was simulated. The anatomic features of the cerebellopontine angle were examined and measured. Results Measuring from the posterior margin of posterior semicircular canal on plane of lateral semicircular canal,the distance was 15.89 ± 1.61 mm to the posterior margin of internal acoustic meatus,27.43 ± 3.25 mm to the inferior margin of trigeminal nerve and 19.39 ± 2.57 mm to the upper margin of glossopharyngeal nerve. The angle between the line connecting the posterior margin of posterior semicircular canal with the posterior margin of internal acoustic meatus and the line connecting the posterior margin of posterior semicircular canal with the upper margin of glossopharyngeal nerve,was 16.78 ± 2.06°. The angle between the line connecting the posterior margin of posterior semicircular canal with the posterior margin of internal acoustic meatus and the line connecting the inferior margin of trigeminal nerve was 16.25 ± 2.88°. Conclusion Endoscopic surgery in the cerebellopontine angle via a retrolabyrinthine approach has advantages of minimal invasiveness,satisfactory exposure and multi -angle visualization and provides an efficient utility in microsurgery.