Article
Optimal time window for cortical mapping in awake craniotomy – data update
Optimales Zeitfenster für kortikales Mapping bei Wachkraniotomie – Datenaktualisierung
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Published: | May 8, 2019 |
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Objective: Presently, there is no way to quantify the patient’s alertness during awake craniotomy. The aim of this work is to extrapolate the patient’s current wakefulness from the intraoperative reaction speed and determine the best time window for cortical mapping after the patient extubation.
Methods: In our current data update, response times were studied in additional 15 patients comprising a total of 35 patients with primary or metastatic brain tumors. All patients underwent surgery following a “sleep-awake-awake” protocol. The registration was done with a Reaction Time Sampler programmed by our team. Reaction times were determined at least once every 10 minutes. Reaction time determination was performed in parallel with our standard methods for evaluation of language and cognitive functions. Statistical analysis was performed using SPSS v24.0 (IBM, New York, U.S.). The data is presented as mean ± standard deviation.
Results: The preoperative response times of our patient cohort (510±124ms) were significantly shorter than those measured during surgery (776±377; p<0,001) (Figure 1 [Fig. 1]). A one-factorial ANOVA (within) showed a significant increase in response times during surgery (p<0.001). Post hoc comparisons on a Bonferroni-corrected α-error level of 0.05 showed significant differences between the average preoperative and all intraoperative response times. Furthermore, there was a significant difference between the average response times in the first 20 minutes and all other time windows (Figure 2 [Fig. 2]).
Conclusion: Patients react significantly slower during surgery than the day before surgery. Furthermore, the response times were significantly longer during the first 20 intraoperative minutes than during the remainder of the operation. Hence, according to our data the optimal time window for cortical mapping starts 20 minutes after extubation of the patient.