Prior to all spine surgeries, a technician will introduce themselves to my patients and say “Hi, I’m here to monitor your nerves.” Recently, a patient asked me why? In short, the neuromonitoring process gives me live-time feedback on how the nerves & spinal cord are doing.
The process of monitoring your nerves involves placing needles throughout your body (including the skull) and monitoring the motor pathways (transcranial motor evoke potentials MEPs), the sensory pathways (somatosensory evoked potentials SSEPs) as well as stimulated and spontaneous EMG’s. This is a complicated process requiring a technician to place the needles, stimulate the EMG’s and MEPs; this information is evaluated by an offsite neurologist. Thankfully the needles are placed and removed with the patient asleep.
Why is this needed? One of the risks of spine surgery whether it is performed for deformity, tumor, infection, fracture or arthritis is nerve and spinal cord injury. As surgeons work around the nerves (sometimes moving them out of the way) or the spinal cord, there is a definite risk of injury. Occasionally, positioning of the patient can place certain nerves at risk (ulnar nerve at elbow or the brachial plexus in the shoulder area with anterior neck surgery). Having a technician talking to your nerves during surgery gives me information as to “how close I am to the nerves” or “did I distract too much across the spine” or “is the correction of the spinal deformity too much?” This information is invaluable in helping me as a surgeon make intraoperative decisions.
Neuromonitoring is a team effort requiring the technician, offsite Neurologist, Surgeon and Anesthesiologist. Certain anesthetics, particularly inhalants or muscle relaxers can interfere with the signals and make obtaining good information difficult. Having the anesthesiologist aware of the effects of certain drugs and communicating with the technician is extremely important.
Ultimately, the goal of any spine surgeon is to perform a surgery and minimize the risk of injury to the nerves and spinal cord. If the technology is available to help achieve that; why not use it.
Dr. Paul Saiz