Microsurgical Anatomy Of The Cerebellopontine Angle Area And Clinical Applications

Objective: To describes the micro-dissection of the petrosal vein in cerebellopontine angle (CPA) and to analyses the the feasibility of cutting off the petrosal vein in the micro-vascular depressions (MVD). Method: The main arteries and veins of 19 cases of the Chinese adult cadaver's heads were perfused with lactoprene, then the diameters of the petrosal vein and the distances between the vein and the nerves in the CPA were measured. In addition, the draining veins of the cerebellas and brain stems were observed when injecting the sodium chloride into the petrosal veins which proximal parts were ligated in 13 cases. Result: In CPA the diameter of the trifacial nerve is 4.5±1.028mm, the facial nerve is 3.7±0.475mm, the petrosal vein with single stem is 2.613±0.527mm, the one with two stem is 1.875±0.777mm,the one with three stem is 1.727±0.514mm. The longth of the petrosal vein with singal stem is 2.392±0.943mm, the one with two stem is 3.726±1.731mm, the one with three stem is 4.053±0.325mm,the minimal distance between the petrosal vein and the trifacial nerve is 2.498±3.524mm, between the petrosal vein and the facial nerve is 2.736±2.662mm. In this study, 19 of 21 (90.5%) petrosal veins has ramus anastomoticus. Conclusion: The relationship of the petrosal vein, trifacial nerve and facial nerve is close, and the compress of petrosal vein to the nerve maybe is the etiopathogenisis of the trigeminal neuralgia and hemi facial spasm. There are ramus anastomoticus between the petrosal vein and the other draining veins in the CPA. In most cases, it is safe to cut off the vein in the MVD when it interferes the operating.