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What is a 'wake up' test and when is it performed?

Dr. Baron S. Lonner

New York, NY

The wake up test was the original form of spinal cord monitoring. This was done in all corrective spinal operations after the instrumentation and correction was performed. Essentially, after the correction, the anesthesia is lightened enough so that the patient will respond to a command to move their hands and feet. Once this is seen, the patient is immediately put back into a deeper sleep. Patients do not remember the wake up test upon awakening fully from anesthesia. Today this is done much less commonly, but is used when spinal cord monitoring reveals an abnormality or when spinal cord monitoring is unreliable for technical reasons or patient factors.

Dr. David W. Polly, Jr.

Minneapolis, MN

A "wake-up" test is where they lighten up on the sleepy medicine, but keep the pain medicine going. You feel like you are in a dream like state and the doctor asks you to move your feet up and down (like pressing on the gas in a car). Once you move your feet, you go back to sleep. This test is done usually after the rods are put in and the spine is straightened.

Dr. Christopher L. Hamill

Buffalo General HospitalBuffalo General Hospital

The wake-up test is preformed when there is a change in spinal monitoring. You will be awakened and asked to wiggle your toes.

Dr. Patrick Bosch

Albuquerque, NM

A “wake-up” test is an added precautionary step to confirm that no injury to the spinal cord has occurred during surgery. The patient’s anesthesia is temporarily lightened so they can respond to commands, such as to move their feet, and then deepened again after a positive response. The patient experiences no pain. Today, with modern spinal cord monitoring, the wake-up test is not used as much.

Dr. John T. Smith

University of Utah Department of Orthopaedic Surgery

Spinal cord evoked potentials are used throughout the course of the correction of the spine. A single technician, experienced in the process, monitors the patient continuously. In the event that the spinal cord evokes potential changes, we would then do a wake up test. A wake up test is what occurs when a patient's anesthetic is lightened to a degree that the patient can follow simple commands. The patient does not actually "wake up", and has no recollection of these events. This type of test is important because the ability to wiggle one's toes indicates that the spinal cord axis is intact and has not been injured.

Dr. James Mooney, III

Detroit, MI

"Wake up" test is performed towards the end of the procedure after all the correction and hardware are in. The patient is slowly awakened and asked to move his or her feet to command. Patients do not remember this and do not appear to be uncomfortable during this procedure. It allows the surgeon to have an absolute determination of neurologic function after correction.

Dr. W. Christopher Urban

Glen Burnie, MD

A “wake up” test is occasionally performed during scoliosis surgery. It is a way of monitoring neurologic function as the deformity is corrected. It involves lightening the anesthesia enough so that the patient can follow simple commands, such as moving their feet, to demonstrate that the spinal cord is functioning properly. Although it is called a “wake up test,” the patient is still under anesthesia and does not feel any pain or remember the test after the surgery is completed. A “wake up” test is performed in circumstances where there is suspicion of a change in neurologic function based on the electrophysiological monitoring that is performed during scoliosis surgery.

Dr. Robert W. Molinari

Rochester, NY

A “wake up” test is performed when spinal cord monitoring becomes abnormal. It is another way of checking spinal cord function during surgery.

Dr. Dennis G. Crandall

Mesa, AZ

After the instrumentation is placed and the curve is corrected, the anesthetic is lightened enough so that the patient can hear and respond, but cannot remember or feel pain. In that dream like state, we ask the patient to move his or her feet to ensure the spinal cord is still functioning. Once the patient moves, we put them back to deep sleep and finish the surgery.

Dr. Thomas G. Lowe

Woodridge Orthopaedics & Spine Center, P.C.

The wake up test in our hospital is used only if the electronic monitoring is abnormal for some reason. Otherwise, we don't use wake up tests anymore. The test when it is done consists of lightening up the anesthetic so you can respond to questions answered which would include "squeeze my hands", "bend your ankles and your knees up and down", and this can be done without the patient experiencing any discomfort or remembering that it was done. It only takes approximately 30 seconds to perform.

Dr. John P. Lubicky

Chicago, IL
Shriner's Hospital for Children

A wake-up test is just what it says. You are awakened while the surgical wound is still open and before the operation is completed. This is typically done after the rods are inserted and the correction is obtained. During the few minutes while you are awake and alert enough to follow commands, you will not feel pain nor remember this because of the medications that you have on board. But you will be awake enough to follow commands given by the anesthesiologist to move your feet, so that the surgeon knows that everything is functioning, at least at that particular moment. Once this test has been performed, you will be re-anesthetized and not awakened again until the end of the procedure.

Dr. Charles E. Johnston, II

Texas Scottish Rite Hospital Orthopedic Group

In the event that there is a question raised about your spinal cord function during the operation, the anesthesiologist will turn off the anesthesia gases and allow you to wake up enough to follow commands. Then you will be asked to move your arms and legs on command to test if neurologic function is intact. As soon as it is determined, you will be put right back to sleep and the operation continued. You will not remember the wake up test.

Dr. Scott J. Luhmann

St. Louis, MO

Essential to a successful spine surgery is the absence of any adverse neurological outcome during or after surgery. Spinal cord monitoring is extremely accurate in identifying neurological deficits during surgery, but there are some individuals in whom spinal cord monitoring is suboptimal or unobtainable. In these cases, a “wake up” test is used—the patient’s anesthesia is temporarily lightened during surgery so that, while following verbal commands, the arms and legs can be actively moved by the patient. After neurological function has been assessed, the patient’s anesthesia is deepened back to the routine level of anesthesia. Because of the type of anesthetic agents used, patients typically have no recall of the “wake up” test after surgery.

Dr. Robert S. Pashman

Los Angeles, CA

Spinal surgery has the potential to irritate the spinal cord. A wake-up test is a technique used to detect any malfunction in the spinal cord during surgery. It involves waking patients up during surgery and asking the patients to move their feet as a test for spinal cord function. Sedation is provided to the patients during the wake-up test, so they have no recollection of being awoken during surgery. I use motor evoked potentials during my cases. Motor and sensory evoked potentials are very sensitive in detecting slight changes in spinal cord function during surgery. In most cases, if the patient is able to undergo both motor and sensory evoked potentials effectively, I am not inclined to use a wake-up test during surgery.

Dr. Stephen Ondra

Chicago, IL

A wake up test is done once a spine has been corrected to a more normal shape, the patient is awakened from anesthesia, though still heavily sedated, and is asked to move their legs to be sure the spinal cord has had no injury in the manipulation. The patient is then typically put back to sleep to allow the operation to be completed. This test used to be done frequently, but is now rarely performed. It is only performed if there is concern that there may be some problem with the spinal cord or in very unusual situations of congenital abnormality, which require a significant manipulation of the spinal cord. For most scoliosis surgery, this test is no longer needed.

Dr. Frank J. Schwab

New York, NY

A "wake up" test involves reducing the degree of anesthesia during surgery allowing a patient to respond to simple commands of arm and leg movement. The patient does not fully awaken and has no recollection of the test after surgery. This type of test is important because the ability to move hands and feet indicates that the spinal cord remains intact through the surgery. In most cases, spinal cord function is monitored through evoked potentials (SSEP, MEP) during correction of the spine. In the event that these potentials change, a wake up test can offer valuable additional information.

Dr. Jean-Pierre C. Farcy

New York, NY
M.M.C. Spine Center

The "wake up test" was first used in France before monitoring became available. The "wake up" test is performed after the instrumentation has been implanted and the correction has been obtained before finishing the operation to check on movement.

Dr. Michael F. O'Brien

Denver Orthopaedics

The wake-up test is the "gold standard" for monitoring during deformity during correction. To a large degree the wake-up test has been replaced by the electrophysiologic monitoring which we typically use. If, however, the electrophysiologic monitoring seems to be inaccurate or it is unclear whether or not the signals being obtained are accurate, the wake-up test will be performed towards the end of the surgical procedure after the instrumentation is in place. The wake-up procedure involves gradually decreasing the anesthetic level until the patient becomes conscious enough to respond to the commands "squeeze my hands" and "wiggle your toes". Patients are often concerned that this will cause a significant amount of pain since the surgical procedure, though suspended, is still in progress. Typically, because of the types of anesthetic agents being used and the still considerable amount of anesthetic agent within the patients' system, patients are unaware of any pain. Often, patients do not even remember having gone through the test.

The commentary above recounts the experiences of these physicians. Medtronic invited them to share their stories candidly. Keep in mind that results vary; not every patient's response is the same. Talk with your doctor to learn more about any products that are mentioned above.

It is important that you discuss the potential risks, complications and benefits of spinal surgery with your doctor prior to receiving treatment, and that you rely on your doctor's judgment. Only your doctor can determine whether you are a suitable candidate for this treatment.

  • Published: June 20, 2002
  • Updated: April 19, 2010