Intrathecal anaesthesia for day-care surgery. A retrospective study of 160 cases using 25- and 26-gauge spinal needles. The records of 160 day-care surgical patients who received intrathecal anaesthesia were reviewed. No major complications were recorded. The incidence of postspinal headache after puncture with a 25-gauge spinal needle was nearly four times more frequent compared to a 26-gauge needle. The occurrence of postspinal headache in patients over the age of 45 years was significantly less frequent (p less than 0.05) than in younger patients. Intrathecal anaesthesia was acceptable to 91% of outpatients in this group. 