We investigated the anti-edema effect of intravenous dexamethasone in a randomized, double-blinded, placebo-controlled study in 40 ASA physical status I and II patients scheduled for trans-oral decompression and posterior fusion. Patients were divided into two groups to receive either placebo or 10 mg dexamethasone one hour prior to induction of anesthesia. After anesthesia induction, oral structures were graded as swelling grade 0 at direct laryngoscopy. Duration of trans-oral surgery, duration of posterior fusion, and total duration of surgery were recorded. After completion of surgery, direct laryngoscopy was repeated, and swelling was graded from 1 to 4. Patients who had a swelling grade of 1 or 2 were extubated while grades of 3 and 4 were transferred to a neurosurgical intensive care unit, and re-assessments were performed 12 hours apart. Patients with swelling grades of 1 and 2 were extubated on each assessment. On statistical analysis of the results, the study found that in comparison to placebo, patients in the dexamethasone group were extubated earlier (P < 0.006, Chi Square for trend). Total duration of surgery and duration of posterior fusion were significantly greater (P < 0.05) in patients who had swelling grade >2 than in patients who had swelling grade < or =2 at completion of surgery (192.50 +/- 16.26, 356.07 +/- 17.06 minutes versus. 158.27 +/- 9.07, 311.41 +/- 14.06 minutes).