Continuous spinal anaesthesia--evolution of a technique.

Continuous spinal anaesthesia is an established technique in which renewed interest has been generated by the availability of small bore catheters suitable for use in the subarachnoid space. Problems include technical difficulty, post dural puncture headache and maldistribution of local anaesthetic, the latter being implicated in the development of caudal equina lesions. Maldistribution of local anaesthetic may possibly be reduced by attempting to place the tip of the catheter at the apex of the lumbo-sacral curve and the use of local anaesthetic solution that is only marginally hyperbaric. This article is in the form of a short review together with an account of the authors' own studies of continuous spinal anaesthesia, conducted to assess the technique for peripheral vascular surgery.