OBJECTIVE: This is a prospective study of the methodology and clinical applications of motor evoked potentials (MEPs) during surgery for intramedullary @entity4097 . METHODS: Transcranial electrical stimulation was used to activate corticospinal motoneurons, and the traveling waves of the spinal cord were recorded through catheter-electrodes placed epi- or subdurally. Intraoperative MEP monitoring was performed in 32 consecutive @entity1 (age range, 1-50 yr) undergoing resection of intramedullary @entity4097 . In 19 @entity1 , MEPs were present before myelotomy (monitorable group), and in 10 @entity1 , MEPs were absent before myelotomy (unmonitorable group). Placement of an epidural electrode was not possible in two @entity1 , and technical problems prevented recording in one. RESULTS: MEP amplitudes decreased intraoperatively by more than 50% of baseline in three @entity1 , all of whom had postoperative @entity451 . Two of these @entity1 recovered within 1 week after surgery, and one remained paraplegic. None of the @entity1 with preserved MEP amplitude (> 50%) sustained immediate significant @entity86 . Motor function was significantly deteriorated 1 week after surgery in one @entity1 in the monitorable group and in five @entity1 in the unmonitorable group. MEP monitorability was significantly associated with good surgical outcome for adult @entity1 (P < 0.05), although not for pediatric @entity1 (P > 0.6). Preoperative motor status and surgical outcome were not significantly associated for the adult (P = 0.13) or pediatric groups (P > 0.4). CONCLUSION: MEP monitorability was a better predictor of functional outcome than the @entity1 's preoperative motor status for the adult group. Significant predictors of MEP monitorability in the adult group were preoperative motor function (P < 0.01), history of no previous treatment (surgery or irradiation) (P < 0.01), and small @entity5 size (P < 0.05). Weak associations with monitorable MEPs existed for low-grade @entity5 (P = 0.09), the presence of baseline somatosensory evoked potentials (P = 0.10), and @entity5 pathological abnormalities ( @entity424 ) (P = 0.13). No associations were determined for sex (P > 0.4), associated syrinx (P > 0.3), or @entity5 location (P > 0.5). In the pediatric group, none of the examined factors were associated with MEP monitorability (P > 0.3). A decline of more than 50% in MEP amplitude during @entity5 removal should serve as a serious warning sign to the surgeon.

The role of motor evoked potentials during surgery for intramedullary XXXX .

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity424 :: ('MESH:D004806', 'Disease') :: ['ependymoma'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'tumors'] @entity86 :: ('MESH:D019106', 'Disease') :: ['postoperative deterioration'] @entity4097 :: ('MESH:D013120', 'Disease') :: ['spinal cord tumors'] @entity451 :: ('MESH:C536857', 'Disease') :: ['paraplegia']
@entity4097 :: (MESH:D013120,Disease) :: ['spinal cord tumors']
