Outcomes of Diffusion Tensor Imaging Tractography in Resection for Vestibular Schwannoma for Facial Nerve Preservation

Introduction: Vestibular Schwannomas (VS) treatment includes surgical resection, but impairment of facial nerve function is a common postoperative complication that limits quality of life. Appropriate pre-operative planning with a visualization of the facial nerve is a vital tool for the proper management of this disease. Diffusion tensor imaging (DTI) tractography creates unprecedented in vivo imaging of the anatomical location of white matter tracts. It can be used preoperatively to visualize the displaced facial nerve to increase safety and improve facial nerve outcomes in VS resection. In this study, we analyze the experience of patients who underwent DTI tractography imaging prior to VS resection at a single institution.

Methods: The medical records of all consecutive patients who underwent preoperative DTI tractography and subsequent surgical resection for VS from March 2012 to April 2015 by the same surgical team were reviewed retrospectively. Reliability was determined by comparing the intraoperative facial nerve location, as determined by the surgeons, with the location mapped by DTI tractography. House Brackmann (HB) score was used to assess postoperative facial nerve function.

Results: A total of 11 patients were included with a mean age of 44 years (range: 19–64 years) and mean follow-up length of 358.27 days (range: 93–1036 days). The average maximum tumor diameter was 2.82 cm (range: 1.7–4.2 cm). Imaging was obtained in all patients and DTI tractography was accurate in 90.9% (10/11) of patients. Postoperatively, 72.73% (8/11) had a HB score of I or II, 18.18% (2/11) had a HB score of III, and 9.09% (1/11) had a HB score of IV.

Conclusions: The outcomes indicate that DTI tractography is an accurate and reliable imaging modality for preoperative facial nerve visualization for VS resection. Its utilization may help reduce postoperative facial nerve damage and improve outcome, safety, and quality of life. Although DTI tractography shows potential in its application, the available literature is scarce and more studies are needed to fully elucidate its role in the VS treatment regimen.