Functional Navigation in Surgery of Cerebral Tumors and Vascular Malformations (FUN)

Functional Navigation in Surgery of Cerebral Tumors and Vascular Malformations: a Prospective, Single Arm Clinical Trial

The purpose of the study is to assess accuracy, advantages of functional neuronavigation and calculate safe distance from motor areas to brain tumors and vascular malformations in image-guided surgery.

Functional images (functional magnetic resonance imaging (fMRI), transcranial magnetic stimulation (TMS), tractography) loaded in neuronavigation are called functional navigation. It is usually combined with anatomical data and allows to display eloquent brain areas. Currently there are plenty of studies concerning possibilities of it's use. In our research we plan to confirm this data and to supplement them with calculating a safe distance from motor areas to various mass lesions in preoperative scans where neurological deficits is not likely to appear after surgery. In case of success this data can be a foundation for further researches specifying indications for use of intraoperative neuromonitoring and possibility of it's replacement with functional navigation in some cases. The purpose of the study is to assess accuracy, advantages of functional neuronavigation and calculate safe distance from motor areas to brain tumors and vascular malformations in image-guided surgery. For each patient a surgeon intraoperatively will assess locations of motor cortex and corticospinal tract found with direct cortical and subcortical stimulation and capture them. After surgery he will compare this data with functional preoperative scans and virtual motor centers constructed based on tractography. Influence of various factors on precision of functional navigation will be studied and safe distance between motor brain areas and mass lesion borders will be calculated.

Surgeon removes brain tumor or vascular malformation and assesses location of motor areas with functional navigation and intraoperative neuromonitoring

Maximal distance from the most remote margin of cortical hand/leg motor area or corticospinal tract in the area of corona radiata in functional navigation to the nearest margin of this area/tract in direct cortical/subcortical stimulation

Accuracy of location of cortical hand/leg motor area, built according to tractography (in millimeters)

Maximal distance from the most remote margin of cortical hand/leg motor area, built according to tractography and loaded into navigation, to the nearest margin of this area in direct cortical stimulation

Constancy of location of cortical hand/leg motor area in fMRI/TMS in relation to precentral gyrus (in millimeters)

Maximal distance from the most remote margin of cortical hand/leg motor area in fMRI/TMS to the nearest margin of precentral gyrus

Which factors lead to disappearing, thinning and dislocation of cortical hand/leg motor areas and corticospinal tract in fMRI/TMS/tractography

Minimal distance from the nearest margin of cortical hand/leg motor area or corticospinal tract to the nearest border of resection of tumor/vascular malformation

This outcome is only measured in patients with no deterioration of motor function after surgery. Safe resection distance = accuracy of functional navigation + distance to stop resection border

Extent of resection = (preoperative tumor volume - postoperative tumor volume) / preoperative tumor volume x 100

Inclusion Criteria: all intracranial tumors arteriovenous malformations cavernous malformations supratentorial localization newly diagnosed age 18-79 years unaltered consciousness error of patient registration in neuronavigation no more than 2 mm possibility to perform "positive mapping" strategy Exclusion Criteria: contraindications to magnetic resonance imaging or transcranial magnetic stimulation inability to build tractography in neuronavigation predicting of intraoperative brain shift 6 mm and more without possibility to correct it real intraoperative brain shift 6 mm and more without possibility to correct it previously performed brain radiotherapy pregnancy breast feeding