Posts Tagged ‘motor evoked potentials’
Background: Primary brain tumors in motor eloquent area are associated with high-risk surgical procedures because of potentially permanent and often disabling motor deficit. Intraoperative primary motor cortex mapping and corticospinal tract (CST) monitoring are well-developed and reliable techniques. Imaging of the CST by diffusion tensor tractography (DTT) is also feasible.
Objective: To evaluate the practical value of 3.0T intraoperative MRI (iMRI) with intraoperative DTT (iDTT) in surgery close to the CST, and to compare high-field iDTT with intraoperative neurophysiological CST mapping during glioma and metastasis resection in a routine setting.
Methods: 25 patients (13 males, 12 females, median 47 years) were enrolled prospectively from June 2010 to June 2012. Inclusion criteria: solitary supratentorial intracerebral lesion compressing or infiltrating the CST according to preoperative MRI. Subcortical CST mapping was performed by monopolar (cathodal) stimulation (500Hz, 400us, 5 pulses). CST DTT was made both at preoperative and intraoperative 3.0T MRI. Subcortical motor evoked potential (scMEP) threshold current and probe-CST distance were recorded at 155 points before, and at 103 points after iMRI. Current-distance correlations were performed both for pre-iMRI and for post-iMRI data.
Background: Resection of gliomas in or adjacent to the motor system is widely performed using intraoperative neuromonitoring (IOM). Despite the fact that data on the safety of IOM are available, the significance and predictive value of the procedure is still under discussion. Moreover, cases of false negative monitoring affect the surgeon’s confidence in IOM.
Objective: To examine cases of false negative IOM to reveal structural explanations.
Methods: Between 2007 and 2010 we resected 115 consecutive supratentorial gliomas in or close to eloquent motor areas using direct cortical stimulation for monitoring of motor evoked potentials (MEPs). The monitoring data were reviewed and related to new postoperative motor deficit and postoperative imaging. Clinical outcomes were assessed during follow-up.