Ultrastructural findings of idiopathic trigeminal neuralgia

Abstract Objective: To further investigate the ultrastructural features of trigeminal nerve root in patients with trigeminal neuralgia without vascular compression. Methods: Trigeminal nerve root biopsy specimens were excised from 12 patients scheduled to undergo posterior fossa craniotomy and root exploration. In 12 of 106 patients no vascular compression was detected. Partial trigeminal posterior rhizotomy was performed. A biopsy sample was taken from the cut portion of the root, followed by electron microscopic examination. Results: The primary finding was the pronounced involvement of the myelin sheath and Schwann cells. In 10 out of 12 specimens, there were some claviform steroid crystals in the Schwann cell cytoplasm. Myelin filled came to fill the liposomes. In all specimens, dysmyelination and demyelination were the main changes of the myelin sheath. Conclusion: Claviform steroid crystals in Schwann cell cytoplasm and lipid deposition in the inner myelin sheath of trigeminal root were found.