Advantages of Diffusion Tensor Tractography of Facial Nerve in Vestibular Schwannomas Surgeries: A Multicenter Study

Objective: The aim is to demonstrate the usefulness of diffusion tensor tractography by the decreased morbidity of the facial nerve and reduction of surgical time in surgery of vestibular schwannomas. Methods: Between 2011 and 2015 were studied by tractography 56 patients with vestibular schwannomas (25 patients in the Hospital Lusíadas Lisbon, Portugal and 31 patients in the Nara Medical University Hospital, Japan). The mean age of patients was 57 ± 12 (72% female). The imaging protocol included Magnetic Resonance Image sequence for the cerebellopontine angle and tractography by diffusion tensor imaging for facial nerve. Patients were operated in two surgical centers: Egas Moniz Hospital, Portugal and Nara Medical University Hospital, Japan. Facial nerve morbidity and surgical time of operated patients with use of tractography ( N = 56) were compared with a group of patients operated without the use of tractography ( N = 42). Results: The preoperative tractography identified the route of the facial nerve in the cerebellopontine angle and its anatomical relationship with the tumor in 56 patients. In 6 patients the facial nerve was not visualized during surgery. There were statistically significant differences in the use of tractography in reducing facial nerve morbidity and reduced surgical time. Conclusion: This study demonstrates that tractography of the facial nerve should be used as routine examination in cerebellopontine angle tumors, decreasing the morbidity of facial and reducing surgical time.