Paraparesis, paraplegia, and quadriplegia are potential complications of spinal cord surgeries or procedures that put the spinal cord at risk. Intraoperative monitoring can alert surgeons and anesthesiologists when patients are at risk for these complications, allowing for prompt treatment to reduce patient harm when warnings are raised. Surgery can then be modified through various interventions, such as reducing the degree of distraction, adjusting retractors, removing or adjusting grafts or hardware, reimplanting or unclamping arteries, and placing vascular bypass grafts.
Time to Take a Closer Look at Spinal Surgery
In the February 21, 2012 issue of Neurology, my colleagues and I at the American Academy of Neurology and American Clinical Neurophysiology Society published an evidence-based guideline update on intraoperative spinal monitoring with somatosensory and motor evoked potentials. The guideline update was needed because the field of intraoperative spinal monitoring has been growing substantially, causing carriers to ask questions about its utility and ability to predict adverse surgical outcomes. Community hospitals are also beginning to look into intraoperative spinal monitoring as a service that they can provide. With changes in coding from the American Medical Association also occurring, it was a good time to answer these questions based on the current literature in evidence-based medicine.
Intraoperative spinal monitoring involves monitoring sensory pathways by applying electrical pulses to the ankles or wrists. These pulses are carried up to the brain and recorded at the scalp. To reach the scalp, the pulses must travel up an intact spinal cord. The motor pathway is the exact opposite; electrical pulses are applied to the brain via the scalp. These pulses are recorded at the peripheral muscles, assuring that the signals are traveling down through the spinal cord.
A Simple Recommendation: Intraoperative Spinal Monitoring
Our guideline update writing group examined 12 Class 1 and Class 2 studies, culled down from 40 that met inclusion criteria. We concluded that intraoperative monitoring is effective to predict increased risks of the adverse outcomes of paraparesis, paraplegia, and quadriplegia in spinal surgery. Surgeons and other operating team members should strongly consider using spinal cord monitoring to help avoid injury. This consideration should take into account that research suggests intraoperative spinal monitoring with somatosensory and transcranial electrical motor evoked potentials costs about $65,000 for each paraplegia avoided. The costs for a lifetime of medical care, lost opportunity, social services, and other factors associated with paraplegia far exceed this price tag. Intraoperative monitoring is hugely cost effective because the best way to treat paralysis is to prevent it from ever happening.
Overcoming Barriers of Intraoperative Spinal Monitoring
Intraoperative spinal monitoring with somatosensory and motor evoked potentials requires technicians, special equipment, and physicians who are trained in supervising these procedures. Therefore, many community hospitals—where the procedure may only be beneficial once per month—have not provided it. Now, outsource services can send technicians and equipment to smaller, community hospitals. They also use telemedicine technology that enables physician experts to provide spinal cord monitoring remotely. With the advancing technology, more patients can now receive this kind of monitoring regardless of the institutions that are closest to them. By increasing our awareness of the benefits of this monitoring, the hope is that more surgeons will adopt the technology and become knowledgeable users in the near future.
Nuwer M, Emerson R, Galloway G, et al. Evidence-based guideline update: intraoperative spinal monitoring with somatosensory and transcranial electrical motor evoked potentials. .Neurology. 2012;78:585-589.
Fehlings M, Brodke D, Norvell D, Dettori J. The evidence for intraoperative neurophysiological monitoring in spine surgery: does it make a difference? Spine. 2010;35:S37-S46.
Sala F, Palandri G, Basso E, et al. Motor evoked potential monitoring improves outcome after surgery for intramedullary spinal cord tumors: a historical control study. Neurosurgery. 2006;58:1129–1143.
Sutter M, Eggspuehler A, Grob D, et al. The validity of multimodal intraoperative monitoring (MIOM) in surgery of 109 spine and spinal cord tumors. Eur Spine J. 2007;16:S197–S208.
Costa P, Bruno A, Bonzanino M, et al. Somatosensory- and motor-evoked potential monitoring during spine and spinal cord surgery. Spinal Cord. 2007;45:86–91.
Weinzierl M, Reinacher P, Gilsbach J, Rohde V. Combined motor and somatosensory evoked potentials for intraoperative monitoring: intra- and postoperative data in a series of 69 operations. Neurosurg Rev. 2007;30:109–116.