Electron microscopic observation of the affected branches of trigeminal neuralgia
Zhao Yunfu ,Jiang Xiaozhong,Han Yusheng (Department of Stomatology,Changzheng Hospital,Second Military Medical University,Shanghai,200003)
Objective: To further investigate whether there are pathologic changes in the affected branches of trigeminal neuralgia, and get a deeper understanding about its pathogenetic mechanism. Methods: Specimens of the affected branches from 6 patients suffering from trigeminal neuralgia were obtained during operation, fixed in 2% glutaraldehyde and postfixed in 1% osmium tetroxide. The material was dehydrated through graded alchols, and then embedded in Spurr resin. Ultrathin sections were stained with both lead citrate and uranyl acetate. The sections were examined under an electron microscope. Results: In all specimens, many fibers appeared to be pathologic changes whereas others were normal. The main finding in the affected branches was the pronounced involvement of the myelin sheath and Schwann cell. Lipid deposit, vacuoles, and myelin sheath fragments were seen in the Schwann cell cytoplasm. The myelin sheath presented the proliferation and disorganization, looseningup of the lamellae, and focal demyelination. Conclusion: There are indeed pathologic changes in the affected branches of trigeminal neuralgia, which involves the Schwann cell and myelin sheath degeneration. Rhizotomy of the trigeminal nerve should be performed in the higher level so as to remove more degenerative nervous tissue and reduce recurrence rate.