Before intraoperative neurophysiological monitoring became widely used, the wake-up test was the only test for spinal cord integrity during spinal surgery, and in particular surgery to correct spinal deformity. It remains a useful test for resolving uncertainty in intraoperative monitoring, or if intraoperative monitoring fails or becomes unavailable.
The patient is awakened during surgery, after the main part of the surgery has been completed (e.g. after placement of the rods in spinal deformity correction surgery). The patient remains on the table and intubated with the surgical site still open, whilst anaesthetic is discontinued or significantly lightened. Neuromuscular blockade needs to be avoided when performing the wake-up test, as this would impair the patient’s ability to move their limbs.
Once the patient is sufficiently awake, they are asked to move their feet. If they are able to do so, this demonstrates intact spinal cord motor function. When the test is complete, anaesthesia is reinstituted, the surgical procedure is completed, and the back is closed.
The usefulness of the wake-up test is now a matter of controversy. Some consider it to be entirely obsolete, but others take the view that it can have its place in certain circumstances, where intraoperative monitoring fails or is unavailable.