Objective To investigate the applied value of diffusion tensor tractography(DTT) and visual evoked potential(VEP) for monitoring lumpectomy of lesion adjacent to the optic radiation.Methods Six patients with intracranial lesions adjacent to the optic radiation performed MRI DTT before operation in order to know relationship between the optic radiation and lesion.Neuronavigation was performed and VEP was recorded continuously during the operation.Results Pathological results of specimens showed that 2 cases were astrocytoma(WHOⅡ),1 case was oligodendroglioma(WHOⅡ),1 case was oligodendro-astrocytoma(WHOⅡ),1 case was anaplastic astrocytoma(WHOⅢ～Ⅳ),1 case was cavernous angioma.No patients were found visual deficit and VEP of 6 cases were normal postoperatively.Conclusions Combination neuronavigation with optic radiation DTT preoperatively and neuronavigation with real-time VEP intraoperatively are reliable to monitor the visual function and is helpful to perform neurosurgical planning near the visual pathway to avoid vision postoperative dysfunction.

Objective To investigate the surgical techniques of the modified presigmoid trans-partial bony labyrinth approach and the advantages in exposure of the petroclival region and in treat the lesion of this area.Methods By simulate the modified presigmoid trans-partial bony labyrinth approach in 15 adult cadaveric heads with the aid of an operating microscope and record important structures in the petroclival region.Results The petroclival region,the posterior cavernous sinus,Meckel cave,the vertebral-basilar artery,the anterior inferior cerebellar artery,the superior cerebellar artery,ipsilateral Ⅲ-Ⅹ cranial nerve nere fully exposured and contralateral Ⅵ cranial nerve were fully exposured.The range of presigmoid exposure was (19.41 ± 1.58)mm,the exposurein of inferior temporal was (14.18 ± 1.88) nun,the maximum exposure angle of slope center depression was (60.54 ± 6.93) °,the depth of operation was (55.87 ± 4.34) mm.Conclusion The advantages of the modified presigmoid trans-partial bony labyrinth approach can earn enough exposures of deep part of petroclival region and posterior part of cavernous sinus,improved petroclival exposure,multiple axes of visualization,preservation of hearing and facial nerve function,and early devascularization of the tumor.