Anatomy And Clinical Research Of Modified Lateral Petrous Bone Approach

Objective: Through the anatomy of the cadaveric heads and simulating approaches for the petroclival area in the heads, looking for more reasonable approaches in that area.Methods: we dissected the adult cadaveric heads fixed by 10% formalin with the microscope, in order to make it clear the important symbol of osseous structure and position; we expound the relationship between position, distribution of all the vessels of and the cranial nerves and brainstem, measurement the distance. Simulating the improvement transpetrosal lateral approach.Results:1, Superior wall of the external auditory canal could be regarded as a signalized point for grinding off the petrosum, which could be used as judging other signalized point.2, Judging the position of the vessels when making use of the juncture of the cisterna.3, The other implication of the front sigmoid sinus, which is not the distance between the sigmoid sinus and the external auditory canal, is not only the distance between the sigmoid sinusand the canalis semicircularis posterior, but also includes the distance between the sigmoid sinus and the ampulla of the canalis semicircularis posterior, the distance between the the canalis semicircularis posterior and the spikes, the length of the sigmoid sinus, the angle between the transverse sinus and the sigmoid sinus.4, Using the discipline of perforating branches' distribution in the cisterna, we could do better in protecting the blood vessels. 5, We could make the petroclival operation more reasonable with the help of the application of three-dimensional spiral CT beforehand. At the same time we can also use the CTA of the head to show the relationship between the vascular and the tumor during the operation for instruction.6, We put forward a improvement transpetrosal lateral approach, which there are some problems to be paid attention to.Conclusion:1, Superior wall of the external auditory canal could be regarded as a signalized point, which is also obviously regarded as the anatomic symbol after craniotomy, definitely is the intersection of the extension line of the zygomatic arch and the superior wall of the external auditory canal.2, Spinke and crista of the petrosal, front sigmoid sinus and condylus occipitalis could be grinded off in the epidural operation. The boundary for grinding off the spinke and crista of the petrosal includes Dorello tube, the petrosum segment of the internal carotid artery, the surface of the canalis semicircularis anterior, and the inferior petrosal sinus.The boundary for grinding off front sigmoid sinus includes the irregular area between the sigmoid sinus, the bulbus venae jugularis, the inferior petrosal sinus, the semicircular canal and the inner ear.The boundary for grinding off condylus occipitalis includes the third juncture of the sigmoid sinus, hypoglossal canal, the condylar of the atlas, the impression of the vertebral artery.3, After grinding off the spinke and crista of the petrosal, front sigmoid sinus, incising the tentorium cerebelli parallel to the crista of the petrosal, lifting the temporal lobe slightly, all these could extend the petroclival's angle. Raising about 22 degrees in the temporal lobe we can clearly show petroclival central part between the saddle and the jugular foramen. Grinding off the front condylus occipitalis, incising the dura matter under the sigmoid sinus, and then inverting the sigmoid sinus to the upper front part, all these could make the petroclival part fully exposed.4, Double bone flap could be fixed by titanium nail for cranium fixed.