Assessment of spinal anaesthetic block

Abstract

Decide on the highest level of innervation that will need to be blocked for the proposed surgery remembering that the underlying organs and peritoneum may come from higher spinal segments

Check for lower limb weakness as an early indicator that the injection was correct. Inability to straight leg raise suggests the block will cover at least all the lumbar segments.

Cold can be used but will usually demonstrate blocked segments higher than those with surgical anaesthesia. Pinprick will generally be closer to the level of surgical anaesthesia.

To be completely happy that surgery can be performed painlessly it is wise to ensure that the level of testing to cold or pinprick is at least 2-3 segments higher than that needed. This will provide a margin for error and also ensure that the operative site does not regain sensation too quickly