NONINVASIVE SOMATOSENSORY MONITORING OF THE INJURED INFERIOR ALVEOLARNERVE USING MAGNETIC SOURCE IMAGING

Purpose: This study evaluates magnetoencephalography (MEG) as an objec tive monitor for the evaluation of post-traumatic inferior alveolar ne rve injuries. Materials and Methods: Six patients with unilateral infe rior alveolar nerve injuries were assessed using conventional sensory examination techniques, All damaged nerves, and their contralateral co ntrols, were then reexamined using MEG technology, Regions of somatose nsory-induced magnetic activity were superimposed on three-dimensional magnetic resonance imaging (MRI) scans to give cortical magnetic sour ce images (MSI). All patients subsequently underwent surgical explorat ion of the damaged nerves. Results: All six patients had no sensitivit y to conventional testing on the damaged side. On evaluation with MEG, all six control nerves had an appropriate cortical signal in response to repetitive lip stimulation. Somatosensory stimulation of two of th e six damaged nerves resulted in cortical magnetic field changes, Surg ical exploration showed that the four nerves with negative MEG tests h ad discontinuity defects. In contrast, the two patients with positive MEG signals had intact nerves. Conclusion: This technology may differe ntiate between intact but damaged nerves and transected nerves.