Local anesthesia and midazolam versus spinal anesthesia in ambulatory pilonidal surgery

Study sample An a priori power analysis, based on published data, revealed that at least 25 patients in each group would be required to detect a 30% reduction in institutional costs, with a power of 90% at the 0.05 level of significance. This sample size would also be sufficient to detect a 30% difference in visual analogue scale (VAS) scores for pain, with a power of 80% at the 0.05 level. A total of 60 patients were included in the study and randomised to one of the two anaesthetic techniques. Thirty received spinal anaesthesia (group 1) and 30 received local anaesthesia with midazolam sedation