A comparison of the effects of desflurane and total intravenous anaesthesia on the motor evoked responses in scoliosis surgery

Background: In the present study, we compared the effects of total intravenous anaesthesia (TIVA) and desflurane anaesthesia on tcMEPs in scoliosis surgery.Methods: The study included 45 patients between the ages of 18 to 50 years, and classified as ASAI-II; which were planned to undergo posterior fusion/instrumentation operations for elective scoliosis. Anaesthesia was maintained using 50-150 mcg/kg/min propofol in Group T(TIVA), and desflurane (0.5 MAC) in Group D, and with infusions of 0.05-0.3 mcg/kg/min remifentanil at 50 % O2 + air in both groups, by applying drugs at doses so that bispectral index (BIS) would be maintained between 40 and 60 throughout the course of anaesthesia. The tcMEP responses were measured four times during the operation, and BIS, train-of-four (TOF), mean arterial pressure (MAP), heart rate(HR), and end tidal CO2(ETCO2) values were recorded simultaneously. In both group the anaesthesia was ended at the final surgical suture. The recovery parameters were recorded.Results: The groups were found not to differ regarding the demographic characteristics, duration of the anaesthesia and the surgery, remifentanil dosage, tcMEP, the simultaneously recorded TOF, MAP, HR and ETCO2 values, and the amount of perioperative bleeding. The cooperation time and the orientation time were shorter in group D. The tcMEP responses were recorded in the appropriate times and amplitudes in both groups. Conclusions: TIVA is primarily used in routine applications in spinal surgery; however our study results revealed that 0.5 MAC desflurane may also be safely used in association with remifentanil, with the resultant correct tcMEP responses.