Intra-operative monitoring of lower extremity motor-evoked potentials by direct cortical stimulation

Object The authors in this study evaluated muscle motor evoked potentials (MMEPs) elicited by transcranial electrical stimulation (TES) and direct cortical stimulation as a means of monitoring during cerebral aneurysm surgery. The analysis focused on the value and frequencies of any intraoperative changes and their correlation to the postoperative motor status. Methods One hundred nineteen patients undergoing surgery for 148 cerebral aneurysms were included in the study. Muscle motor evoked potentials were elicited by a train of five constant-current anodal stimuli with an individual pulse duration of 0.5 msec and a stimulation rate of 2 Hz. Stimulation intensity was up to 240 mA for TES and up to 33 mA for direct cortical stimulation. The MMEPs were continuously recorded from the abductor pollicis brevis and tibialis anterior muscles bilaterally and from the biceps brachii and extensor digitorum communis muscles contralateral to the surgical side. The motor status was evaluated immediately after surgery and 7 days later. In 97% of the patients MMEPs were recordable for continuous neurophysiological monitoring of the vascular territory of interest throughout the surgery. In 14 patients significant intraoperative MMEP changes occurred, resulting in a transient motor deficit in one patient and a permanent motor deficit in six. The permanent loss of MMEPs in three patients was followed by a permanent severe motor deficit in one patient and severe clinical deterioration in the other two. Conclusions Data in this study demonstrated that MMEPs are a useful means of intraoperative neurophysiological monitoring of motor pathway integrity and predicting postoperative motor status. The intraoperative loss of MMEPs reliably predicts both severe and permanent postoperative motor deficits.

Download Full-text

LP34: Intraoperative direct cortical stimulation motor evoked potentials: preliminary stimulus parameter recommendations based on rheobase and chronaxie

Clinical Neurophysiology ◽

10.1016/s1388-2457(14)50603-7 ◽

2014 ◽

Vol 125 ◽

pp. S184-S185

Author(s):

D. MacDonald ◽

T. Abalkhail ◽

I. Al Thubaiti ◽

F. Al Otaibi ◽

B. Stigsby ◽

...

Keyword(s):

Evoked Potentials ◽

Motor Evoked Potentials ◽

Cortical Stimulation ◽

Stimulus Parameter ◽

Direct Cortical Stimulation

Download Full-text

Predicting Hand Motor Recovery in Severe Stroke: The Role of Motor Evoked Potentials in Relation to Early Clinical Assessment

Neurorehabilitation and Neural Repair ◽

10.1177/1545968308317578 ◽

2008 ◽

Vol 23 (1) ◽

pp. 45-51 ◽

Cited By ~ 59

Author(s):

Annette A. van Kuijk ◽

Jaco W. Pasman ◽

Henk T. Hendricks ◽

Machiel J. Zwarts ◽

Alexander C. H. Geurts

Keyword(s):

Lower Extremity ◽

Evoked Potentials ◽

Upper Extremity ◽

Clinical Assessment ◽

Predictive Value ◽

Motor Evoked Potentials ◽

Motor Recovery ◽

Stroke Patients ◽

Abductor Digiti Minimi

Objective. The primary aim of this study was to compare the predictive value of motor evoked potentials (MEPs) and early clinical assessment with regard to long-term hand motor recovery in patients with profound hemiplegia after stroke. Methods. The sample was an inception cohort of 39 stroke patients with an acute, ischemic, supratentorial stroke and an initial upper-extremity paralysis admitted to an academic hospital. Hand motor function recovery was defined at 26 weeks poststroke as a Fugl–Meyer Motor Assessment (FMA) hand score >3 points. The following prognostic factors were compared at week 1 and week 3 poststroke: motor functions as assessed by the FMA upper-extremity and lower-extremity subscores, and the presence of an MEP in the abductor digiti minimi and biceps brachii muscle. Results. Both the presence of an abductor digiti minimi–MEP and any motor recovery in the FMA upper-extremity subscore showed a positive predictive value of 1.00 at weeks 1 and 3. The FMA lower-extremity subscore showed the best negative predictive value (0.90; 95% CI 0.78-1.00 at week 1 and 0.95; 95% CI 0.87-1.00 at week 3). Conclusions. In stroke patients with an initial paralysis of the upper extremity the presence or absence of an MEP has similar predictive value compared with early clinical assessment with regard to long-term hand motor recovery.

Download Full-text