The difference in density between the cerebrospinal fluid (CSF) and local anaesthetic solutions should be considered as a means of restricting drug distribution in the subarachnoid space. Conventional spinal anaesthesia may not be suitable for routine use in outpatients and anaesthetists should familiarise themselves with techniques that are associated with a rapid recovery profile. Using a small dose of either hypobaric or hyperbaric local anaesthetic injected at low speed through a directed needle in patients lying in the lateral position for 15 to 30 minutes can result in preferential development of spinal anaesthesia on the operated side. Unilateral spinal anaesthesia may be indicated for short procedures involving only one of the lower limbs. Potential haemodynamic benefits have increased interest in methods achieving unilateral spinal anaesthesia, because hypotension is a common complication of spinal anaesthesia with larger doses of local anaesthetic 1. When haemodynamic change was compared between bilateral and unilateral spinal block from the same dose of hyperbaric bupivacaine (8 mg), the frequencies of hypotension were 22.4% and 5%, respectively 2. The advantages of unilateral or selective versus conventional subarachnoid anaesthesia are better haemodynamic stability 1,2,5,6 , faster motor and sensory recovery 2-4 and decreased urinary retention 3,4,6,7. Unilateral spinal anaesthesia is associated with a lower rate of cardiovascular complications due to less sympathetic block than bilateral spinal anaesthesia 5. The patients' satisfaction with the unilateral technique appears high 3,4,8,9. The rationale behind our approach was to produce spinal anaesthesia restricted to the operative side alone and to obtain surgical anaesthesia just sufficient for the duration of surgery. The primary

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Practical experience in the use of intravenous regional anaesthesia in hand surgery on 632 patients is reported. The safety of the anaesthesia, the efficacy of the procedure and the patient-comfort are well attested in this study. We recommend that its role should be established particularly in busy orthopaedic surgery departments where both elective and emergency work-loads on hand surgery are heavy.