Microanatomy Of The Petrosal Vein And Its Clinical Application In Microvascular Decompression For The Treatment Of Trigeminal Neuralgia

Objectives Through observation and study of 10 cadaveric head specimens of anatomy with mieroseope, to analyze the anatomic data about Petrosal vein and surrounding structure. Discussing the meaning in microvascular decompression in trigeminal neuralgia the clinical surgery. Providing the anatomical basis and the reference about processing the regional related lesions and about how to process petrosal vein.Methods 1) Base on 10 cases of formalin-fixed adult cadaveric head specimens after perfusion of the arteries and veins with colored latex, wedissectted and observed the interrelation in cerebellopontine angle area of petrosal vein, distance and modality petrosal vein and trigeminal nerve. 2) Collected 30 cases of microvascular decompression in the treatment of primary trigeminal neuralgia in patients with clinical observation and operation of video data, which during the period of December 2012 to December 2013 in Department of Neurosurgery of North China University of Science and Technology. Combined with the research of anatomy of Petrosal vein results and observe the application of Petrosal vein during the operation, the clinical significance in the operati-on was discussed. 3) All measured data were statistically processed and presented in the mean(range and measured value) style and were selectived correlation numerus process t test.Results 1) The Petrosal vein relatively fixed position in the posterior fossa, and is anatomical variation in the individual. The SPV trunk may comprise of a single large vein or of a common stem formed by union of several smaller veins. In its typical form, the SPV has a V or inverted Y configuration and was floating free in the posterior fossa, and to be fixed around the arachnoid. The measured length is(8.77 ± 3.40) mm, and the outer diameter is(3.49 ± 0.66) mm. 2) 10 cases of a total of 20 cadaver specimen sides. 13 sides(65%) have 1 branche, 6 sides(30%) have 2 branches, 1 sides(5%) have 3 branches. Among the total 3 trunk have 1 branch, 12 trunks have 2 branches, 10 trunks have 3 branches, 3 trunks have 4 branches. In all CPAs, the vein of the cerebellopontine fissure alone or in union with several other tributaries joined to form a superior petrosal vein. In those CPAs where there was only 1 superior petrosal vein, it was a continuation of the vein of the cerebellopontine fissure. In those CPAs where there were 2 or 3 superior petrosal veins, 1 was always formed by the vein of the cerebellopontine fissure and the others were formed by either the transverse pontine vein, the pontotrigeminal vein, or the vein of the middle cerebellar peduncle. 3) The petrosal vein are subdivided into the medial, intermediate, and lateral draining point groups on the basis of their draining points into the superior petrosal sinus. The intermediate draining point group drains into the sinus immediately above the internal acoustic meatus, the medial group drains into the sinus medial to themeatus, and the lateral group drains into the sinus lateral to the meatus. In all 10 cases of a total of 20 cadaver specimen sides. 6 sides are lateral type, 12 sides are intermediate type, 2 sides are medial type. 4) The distance between the branches joint of petrosal vein and the root of trigeminal nerve is(3.75±1.45)mm. 4 sides of petrosal vein or its branches contact trigeminal nerve, 3 sides are the transverse pontine vein. 1 side is small branch of the petrosal vein. 2 branche joints of petrosal veins are interior situated on the root of trigeminal nerve, 22 branches are outside above, 4branches are above. 5) Retrospective analysis of 30 cases of microvascular decompression in the treatment of primary trigeminal neuralgia clinical and operation of video data. 44 petrosal veins were found, 18 cases(60%) have 1 branch, 10 cases(33.3%) have 2 branches, 2 cases(6.7%) have 3 branches. 4 cases had venous conflict by petrosal vein or its branches, alone in 3 cases, or in association with an artery in 1 case. The conflict was situated at REZ in 1 cases, midcisternal portion in 3 cases, and porus was no found. The major part was the pontine affluent of the petrosal vein, and the cerebellopontine fissure veins often probing the trigeminal nerve disorder.Conclusions 1) Petrosal vein relatively fixed position in the posterior fossa, but large differences of individual anatomy. 2) Venous compressions were not only at REZ but also at the mid-cisternal portion, and also and even more so at the porus. These findings justify complete exploration of the entire root from REZ to the porus. 3) Familiar petrosal vein microsurgical anatomy and structural relationships with the surrounding tissue, microvascular decompression surgery for treatment of primary petrosal vein protection, reduce venous complications, prevent omissions liability vessels, raise surgical safety and postoperative pain relief has a positive meaning.