Continuous spinal anaesthesia using the incremental technique was used in nineteen high risk patients with multiple medical problems, seventeen of whom were elderly, for lower limb orthopaedic and pelvic surgery. An intrathecal catheter (18G/28G) was inserted under local anaesthesia via the lumbar interspinous space. Spinal anaesthesia was induced with small incremental doses of 0.5% bupivacaine hydrochloride through the intrathecal catheter to achieve the level of analgesia required for surgery. The duration of surgery ranged from 45 to 300 minutes (mean + S.D 100 + 37 min). The initial volume of 0.5% bupivacaine required for surgery ranged from 0.8 ml-2.0 ml (1.2 + 0.7 ml) and the total volume ranged from 0.9 ml to 3.1 ml (mean + S.D 1.4 + 0.7 ml). Haemodynamic stability was well maintained perioperatively. Only two patients required 6 mg of ephedrine and 1 mg of aramine respectively for a greater than 25% reduction in systolic blood pressure with induction of spinal anaesthesia. Intrathecal morphine 0.1-0.3 mg was administered to 15 patients at the end of surgery for postoperative pain relief with good effect. One patient developed late respiratory depression from an inadvertent overdose of intrathecal morphine. No neurological sequelae were noted and no patient developed a postdural puncture headache. The use of the microcatheter was discontinued in the U.S.A and Australia following four case reports of cauda equina syndrome with this technique. Current opinion, however, is that the reported cauda equina syndrome was due to the neurotoxic effects of lignocaine 5% that was used and not due to the microcatheter per se. Continuous spinal anaesthesia is now used widely in Europe when cardiovascular stability is desired in poor risk patients undergoing lower limb and lower abdominal surgery.