TY - JOUR
T1 - Factors affecting successful localization of the central sulcus using the somatosensory evoked potential phase reversal technique
AU - Sheth, Sameer A.
AU - Eckhardt, Christine A.
AU - Walcott, Brian P.
AU - Eskandar, Emad N.
AU - Simon, Mirela V.
PY - 2013/5
Y1 - 2013/5
N2 - BACKGROUND:: Perirolandic surgery is associated with an increased risk of postoperative neurological deficit that can be reduced by accurate recognition of the location of sensorimotor cortex. The median somatosensory evoked potential (MSSEP) phase reversal technique (PRT) reliably identifies the central sulcus (CS) intraoperatively, but does require additional surgical time. Awareness of factors that lengthen the time required for MSSEP PRT has important implications for surgical planning. OBJECTIVE:: To identify factors that affect the time required for CS localization via MSSEP PRT. METHODS:: Multivariate Cox regression analysis, applied in 100 consecutive cases of perirolandic surgery at a single institution from 2005 to 2010, during which CS localization was attempted via a standardized MSSEP PRT. RESULTS:: The CS was reliably identified in 77 cases. The mean time to identification was 5 minutes (SD = 5; range, 1-20 minutes). Lesion location either very close to the CS (within the postcentral gyrus) or at an intermediate distance (with edema extending very close to the CS) independently decreased the rate at which the CS was identified by 73% (hazard ratio: 0.27, P < .001) and 55% (hazard ratio: 0.45, P = .007), respectively. Highly destructive pathology reduced this rate by 42% (hazard ratio: 0.58, P = .03), after adjusting for other important factors. Epidural recording, age, and the presence of a burst suppression pattern on the electroencephalogram had no effect. CONCLUSION:: MSSEP PRT is an effective method for CS identification and only marginally lengthens the operative time. However, difficulty in CS localization can be expected in the presence of postcentral gyrus lesions, edema distorting perirolandic anatomy, and with highly destructive pathology. ABBREVIATIONS:: CI, confidence intervalCS, central sulcusECoG, electrocorticogramHR, hazard ratioMSSEP, median somatosensory evoked potentialPRT, phase reversal technique.
AB - BACKGROUND:: Perirolandic surgery is associated with an increased risk of postoperative neurological deficit that can be reduced by accurate recognition of the location of sensorimotor cortex. The median somatosensory evoked potential (MSSEP) phase reversal technique (PRT) reliably identifies the central sulcus (CS) intraoperatively, but does require additional surgical time. Awareness of factors that lengthen the time required for MSSEP PRT has important implications for surgical planning. OBJECTIVE:: To identify factors that affect the time required for CS localization via MSSEP PRT. METHODS:: Multivariate Cox regression analysis, applied in 100 consecutive cases of perirolandic surgery at a single institution from 2005 to 2010, during which CS localization was attempted via a standardized MSSEP PRT. RESULTS:: The CS was reliably identified in 77 cases. The mean time to identification was 5 minutes (SD = 5; range, 1-20 minutes). Lesion location either very close to the CS (within the postcentral gyrus) or at an intermediate distance (with edema extending very close to the CS) independently decreased the rate at which the CS was identified by 73% (hazard ratio: 0.27, P < .001) and 55% (hazard ratio: 0.45, P = .007), respectively. Highly destructive pathology reduced this rate by 42% (hazard ratio: 0.58, P = .03), after adjusting for other important factors. Epidural recording, age, and the presence of a burst suppression pattern on the electroencephalogram had no effect. CONCLUSION:: MSSEP PRT is an effective method for CS identification and only marginally lengthens the operative time. However, difficulty in CS localization can be expected in the presence of postcentral gyrus lesions, edema distorting perirolandic anatomy, and with highly destructive pathology. ABBREVIATIONS:: CI, confidence intervalCS, central sulcusECoG, electrocorticogramHR, hazard ratioMSSEP, median somatosensory evoked potentialPRT, phase reversal technique.
KW - Brain neoplasms
KW - Cerebral cortex
KW - Electrophysiology
KW - Intraoperative
KW - Monitoring
KW - Neurosurgery
KW - Somatosensory evoked potentials
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U2 - 10.1227/NEU.0b013e3182897447
DO - 10.1227/NEU.0b013e3182897447
M3 - Article
C2 - 23381491
AN - SCOPUS:84876720955
SN - 0148-396X
VL - 72
SP - 828
EP - 834
JO - Neurosurgery
JF - Neurosurgery
IS - 5
ER -