Motor and sensory function must be assessed during surgery of scoliosis so as to avoid possible damage to the spinal cord. The intraoperative awakening by a specific benzodiazepine antagonist, flumazenil, was studied prospectively in 20 patients (mean age 17 years) undergoing surgery for severe scoliosis. Premedication consisted in 0.02 mg.kg-1 atropine and 0.15 mg.kg-1 midazolam. Anaesthesia was induced with a mean dose of 0.42 +/- 0.1 mg.kg-1 midazolam, 1.6 +/- 0.6 micrograms.kg-1 fentanyl and 0.1 mg.kg-1 pancuronium. Maintenance was obtained with a continuous infusion of 0.22 +/- 0.1 mg.kg-1.h-1 midazolam, 66% nitrous oxide in oxygen, and fentanyl (1.6 +/- 0.5 micrograms.kg-1.h-1). Nitrous oxide and midazolam were respectively stopped 10 and 1 min before giving the antagonist (5 micrograms.kg-1 flumazenil) if required (17 out of the 20 patients). Eye opening occurred a mean 42 +/- 32 s after giving the antagonist. At this time, there was a significant increase in mean arterial blood pressure (+ 11 mmHg) and heart rate (+ 7 b.min-1). Thiopentone, 66% nitrous oxide in oxygen and 0.5% halothane were given to re-induce and maintain anaesthesia for completion of the procedure. The day following surgery, 19 patients were unable to remember the period of intraoperative awakening. One patient, although remembering the episode, did not experience any pain or any other disagreement in relation to it. Two patients were given a second dose of flumazenil at extubation so as to improve the quality of their recovery.(ABSTRACT TRUNCATED AT 250 WORDS)