Abstract SNACC-5

Return to Poster Listing

Anesthesia for Stereotactic Electroencephalograph monitoring A Case Series

Chakrabarti R, Avitsian R, Tewari A, Pal R
Cleveland Clinic Foundation, Cleveland, OH, USA

Stereoelectroencephalography(SEEG) is an invasive diagnostic procedure for localizing drug resistant focal epilepsies. Despite an abundant literature on surgical details of SEEG, there seems to be a shortage of discussion on its anesthetic considerations. We describe our experience regarding different anesthetic techniques for this procedure in a tertiary neurosurgical center.

Introduction : Anesthesia for intra-operative EEG monitoring is unique. With current evolution of SEEG to define epileptogenic zone (EZ) [1] new challenges arise. In this descriptive study we aim to portray our experience on a relatively large number of SEEG implantation cases, describing the principles and variety of anesthetic techniques.

Surgical technique: In modern technique Dyna CT, MRI and angiography images are fused with dedicated fusion software .Stereotactic neuronavigation software is used to plan an avascular and precise trajectory for depth electrode implantation [2]. More recently a robotic arm is used for implantation. Calculated trajectories guide the robotic arm to precisely locate the point of drilling for implantation of probes [3].

Methodology: After institutional review board approval was obtained and health insurance portability and accountability act standard was strictly followed, a retrospective anesthetic chart review of all intra-operative SEEG placement and EEG monitoring over last two years was conducted. Inclusion criteria were all 18 and above patients who underwent SEEG implantation and intra-operative EEG monitoring between January 2011 to December 2013. Charts were reviewed for different anesthetic maintenance techniques and use of midazolam (dose and timing).

Results: The result of the chart review including the patient characteristic and medications used are mentioned in table 1 and 2.
139 included. 15 patients were <18 yrs .124 patients were 18-66 yrs. 54 (43.55%) were male and 70 (56.45%) female.
Table 1:
Midazolam timing Number Percentage (%)
2 mg at induction 61 49.19
1 mg at induction 22 17.74
Total( 2 mg+1mg)at induction 83 66.94
3 mg at emergence 9 7.26
Midazolam Not used 32 25.81

Table 2:
IV drug for maintenance Sevoflurane MAC for maintenance Number Percentage (%)
Remifentanil Infusion 0.5 MAC 99 79.84
Ketamine Infusion 0.5 MAC 9 7.26
Intemittent Rocuronium 1 MAC 16 12.9

Conclusion: A fine balance is required to provide anesthesia while monitoring intra –operative EEG and this was achieved by combination of intravenous and volatile technique. Synergistic effect of IV and Inhalational medication helps to keep the concentration of both low without affecting EEG monitoring while providing adequate anesthesia. Further structured study for EEG quality is required to prove any role of seizure foci enhancers such as Ketamine.

Back to Top