Abstract: Objective To study the diagnosis and microneurosurgical treatment of gaint dumbbell trigeminal neurinoma.Methods 35 cases of dumbbell trigeminal neurinoma which had been diagnosed by MRI were operated through microsurgery. 28 cases were through the subtemporal transtentorial approach. 5 cases were through the frontotemporal with zygomatic osteotomy approach, 2 cases received operation through retrosigmoid approach.Results Total resection was achieved in 33 cases(94.3%), subtotal resection in 2 cases. No operative death. Their pathohistological diagnosis were neurinoma. The symptoms before operation such as headache was improved. The abducence nerve palsy was occurred in 8 cases postoperativly, 4 cases was recovered at least. There was no perminant disfunction of the oculomotor nerve. The patients with hydrocephalus were improved after operation. The follow-up period was between 3～60 months, and the follow up rate was 51.4%. The cases of total resection were no recurrences. The case of subtotal resection was stable after γ-knife treatment.Conclusion The gaint dumbbell trigeminal meurinoma shows its characters of MRI. The approprite individual approach and a good exposure during operation are very important.

Key words: trigeminal neurinoma, microneurosurgery, approach