Microsurgery Anatomy Study Of Subtemperal Anterior Transpetrosal Approach

Objective: To determine the microanatomical features in the base of the middle fossa through subtemperal anterior transpetrosal approach with microscrope, and discuss the feasibility of refinement the approach.Methods: Eight adult cadaveric heads fixed with formalin were used , red pigment were injected red into the internal carotid artery and the vertebral artery. Fixed these specimen on the operating table with Mayfield headrest. A question mark skin incision is made from below the zygoma to the midline, with the temporal is muscle reflected anteriorly and the scalp to expose the frontotemporal region and zygomatic arch. And then, resected zygomatic arch elevated dura from the floor of the middle fossa, divided the middle meningeal artery, removed the bone lateral to the foramen spinosunu drilled the petrous bone, we can measure the parameters between the marks. After this , we dissected the tentorium of cerebellum , the superior petrosal sinus;reflected the tentorium anteriorly on the surface of trochlear nerves;opened the posterior portion of the cavernous sinus;drilled the bone of petrous tip under trigeminal ganglion. We evaluate the exposure area of the region of petroclival and retrochiasma under microscope.Result: (1)Resection zygomatic arch .remove the bone lateral to the foramen spinosum can shorten the length of manipulation 1. 32cm widen operative view 12. (2)The size of the lateral bone of temper removed can be 2. 8cmJ, the depth be 2.26cm, which is helpful to the exposure of the region of retrochiasma. (3)The size of the windows in superior and medial surface of petrous bone averaged 2.5cm2 1.7 cm2, respectively.Conclusion: (1)The technique of subtemporal anterior transpetrosal approach is better and more complicated than the one of classic subtemporal approach. It' s helpful to lessen the retraction of temporal lobe and gainbetter view field operative field, through drilling petrous bone resecting the tentorium of cerebellar. It' s adapt for the priceple of the mini-invading neurosurgery. (2)After above, we removed the temporal bone of lateral trigone .which is useful to impove the operative field and the view to retrochiasma area.