[Continuous spinal anesthesia]

Continuous spinal anaesthesia (CSA) is a further means of central nerve block for anaesthesia besides single-shot spinal (SSS), combined spinal/epidural, and epidural anaesthesia. Major advantages compared to SSS are the possibility of subsequent injection of local anaesthetic via the indwelling catheter, which enables analgesia to be maintained over a longer period. Moreover, the haemodynamic effects are diminished by this mode of application. The most important advantages of CSA compared to continuous epidural anaesthesia are the more rapid onset of action, better quality of analgesia, and better muscle relaxation. Since small doses of local anaesthetic are used in CSA, there is less danger of systemic toxic reactions. The microcatheters used up to now for CSA are introduced via relatively large needles that cause perforation trauma to the dura, resulting in loss of cerebrospinal fluid (CSF) and thus a higher incidence of post-dural punctive headache. Hence, further technical developments must have the objectives of reducing needle diameter and increasing catheter diameter. Perforation trauma to the dura is reduced by using small needles. Use of a larger catheter enables better mixing of the local anaesthetic with the CSF, and it is easier to aspirate CSF in order to establish the correct position of the catheter.