Article
Intraoperative direct electrical motor cortex stimulation (DECS) during central tumor surgery: Dispensable in the era of functional imaging and neuronavigation?
Intraoperative direkte elektrische Motorkortexstimulation zur Identifiktion des Gyrus präcentralis bei der Chirurgie zentraler Tumore: überflüssig in den Zeiten von funktioneller Bildgebung und Neuronavigation?
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Published: | April 23, 2004 |
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Outline
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Objective
Today, functional MR imaging (fMRI) is the routine tool for preoperative identification of the motor cortex in patients with tumors of the rolandic area. With the help of neuronavigation, the functional data could be transferred into the operative field. In doing so, a high success rate for intraoperative localisation of the motor cortex has been reported, and direct electrical motor cortex stimulation (DECS), which is the gold standard for intraoperative motor cortex identification, has been considered to be dispensable. It was the aim of the study to investigate in a large prospective series, whether functional navigation indeed has the potential to replace DECS.
Methods
In 60 patients with a tumor in or directly adjacent to the rolandic area, fMRI (activation of hand and foot, BOLD technique) was done. On the base of the fMRI, the motor cortex localisation was defined and neuronavigationally transferred into the operative field. During surgery, the actual position of the motor cortex was defined by DECS and evoked potential registration in the contralateral upper and lower extremity (8 muscles). This actual position was compared with the motor cortex data of functional neuronavigation.
Results
The localisation of the motor cortex, as indicated by fMRI and neuronavigation, corresponded to the true DECS-defined motor cortex site in 50 of the 60 patients (83 %).
Conclusions
Our results clearly indicate, that the suggestion to use soley functional neuronavigation to identify the motor cortex during central tumor surgery is not justified. The 17 % failure rate of correct motor cortex identification would expose the patient to an unacceptable risk of a postoperative motor deficit.