Complete failure of spinal anaesthesia in obstetrics.

Intrathecal anaesthesia, either as a single shot-spinal or as part of a combined spinal-epidural technique, is now widely accepted as the management of choice for caesarean section. It generally produces rapid and predictable anaesthesia, yet occasionally fails for no apparent reason. Four case reports of seemingly inexplicable complete failure of intrathecal anaesthesia are presented, together with a literature review of other cases and possible causes of the failure, which include anatomical abnormality, drug failure and management failure.