In spine surgery, some of the most important decisions are made when something appears to be going wrong. A neuromonitoring signal suddenly disappears. An alarm sounds. A tracing drops.
The surgeon has to decide whether a nerve is actually in danger or whether the monitoring system itself is sending a false warning. For decades, spine surgeons have learned to operate around that uncertainty.
Comron Saifi, MD, C. James and Carole Walter Looke Chair in Orthopedic Spine Surgery at Houston Methodist and medical director of Houston Methodist Spine Center at Baytown, believes they shouldn’t have to.
“We’ve accepted false positives as part of spine surgery for a long time,” Dr. Saifi told Becker’s. “The problem is that every false positive forces you to make decisions based on information that may not actually be true.”
Those decisions matter. A concerning signal can prompt additional decompression, longer operative times or further surgical exploration. The warning is intended to protect the patient. But if the warning is wrong, the response can introduce risks of its own.
That question, whether surgeons can trust what they are seeing, spurred Dr. Saifi and his multidisciplinary team at Houston Methodist to develop a new neuromonitoring approach that is rapidly gaining attention across spine surgery.
Nearly two years after publishing the first comparative study, transabdominal motor evoked potentials, or TaMEPs, are increasingly being adopted by neuromonitoring providers and spine programs throughout the country. Dr. Saifi believes the technique is on track to become a new standard for lumbar spine monitoring.
The reason is straightforward. The technology appears to dramatically reduce false alarms.
The problem hiding inside the monitoring system
Modern lumbar spine surgery relies heavily on transcranial motor evoked potentials. The concept is elegant. Signals begin in the brain and travel through the central nervous system to the nerve roots surgeons are attempting to protect.
The challenge is that the same pathway creates opportunities for interference. Anesthesia changes. Blood pressure fluctuations. Inhaled gases. Temperature shifts. Each can alter the signal. As a result, surgeons frequently find themselves trying to determine whether a signal change represents a neurologic injury or simply noise within the system.
“You have to make a decision,” Dr. Saifi said. “Do I do more surgery? Do I do another decompression? Is there really a problem, or is the monitoring system misleading me?”
The question becomes especially important in lumbar surgery, where reliable monitoring can directly influence intraoperative decision-making.
A different approach
Rather than sending signals through the brain and spinal cord, Dr. Saifi’s team asked a simpler question: What if the central nervous system could be bypassed altogether?
Transabdominal MEPs stimulate the lumbosacral nerve roots directly near the conus at approximately L1 using a small number of additional leads placed on the abdomen and back. The result is a signal that is significantly less vulnerable to the variables that routinely affect traditional monitoring.
“They just work,” Dr. Saifi said. “They bypass the entire central nervous system, so even when the anesthesia changes, the signal holds.”
The technology may also help surgeons localize neurologic issues more precisely. According to Dr. Saifi, a preserved transabdominal signal combined with a lost transcranial signal suggests the problem is occurring above the conus rather than at the lumbar nerve root itself, providing additional information during surgery.
The improvement became most obvious in one of the most difficult areas of spine surgery: monitoring the quadriceps during lateral lumbar procedures.
“The quadriceps are the hardest muscle to monitor with TcMEPs, and that’s exactly where TaMEPs are strongest,” he said. In the operating room, the difference can be immediately visible.
“You fire at the skull and nothing comes; you fire at the conus and you see a beautiful signal, so you know the quads are fine,” Dr. Saifi said. For surgeons accustomed to troubleshooting unreliable signals, the contrast is difficult to ignore.
The number that got people’s attention
The team’s published study included 220 patients and directly compared transabdominal and transcranial monitoring. The magnitude of the improvement surprised even the investigators.
“In our study, TaMEPs improved both sensitivity and specificity from 0.89 to 0.98 versus TcMEPs,” Dr. Saifi said. “Put differently, TaMEPs cut missed injuries and false alarms from roughly 11% to 2%, about an 80% reduction in both.”
For spine surgeons, that statistic carries implications far beyond monitoring. False positives do not simply create anxiety in the operating room. They can change what surgeons do next.
A surgeon who believes a nerve is compromised may perform additional decompression, extend the procedure or alter the surgical plan altogether. The problem is not the response. The problem is responding to a problem that does not actually exist.
“Someone may be doing significantly more work in surgery because they believe a nerve isn’t functioning properly,” Dr. Saifi said. “Then they can end up creating problems while trying to solve one that never existed.”
Why the timing matters
The technology arrives at a moment when lumbar spine surgery is rapidly moving into ASCs. As CMS continues removing procedures from the inpatient-only list, surgeons are performing increasingly complex cases in outpatient settings.
That trend raises the importance of confidence and predictability. When patients are expected to go home the same day, surgeons have less tolerance for uncertainty.
“More accurate monitoring is what lets surgeons and patients feel comfortable moving minimally invasive fusions to the surgery center,” Dr. Saifi said. The implications extend beyond safety. Reliable monitoring may become one of the foundational technologies supporting the continued migration of spine procedures into ASCs.
A rare innovation in healthcare
Many healthcare innovations require significant capital investment, extensive training or years of workflow redesign. Transabdominal MEPs do not. The technology integrates into existing monitoring systems using a small number of inexpensive leads.
“It really doesn’t cost anything additional,” Dr. Saifi said. That creates an unusual equation.
Neurologic complications remain among the most devastating and expensive events in spine surgery. Preventing even a small number of injuries can avoid substantial downstream costs associated with reoperations, readmissions and long-term disability.
“The economics of a neurologic injury are enormous,” Dr. Saifi said. “Prevention is really what we’re aiming for.”
What comes next
Dr. Saifi believes the next challenge for neuromonitoring is standardization, particularly around anesthesia management and reducing variability across operating rooms.
Transcranial monitoring remains essential for cervical and thoracic procedures, where transabdominal techniques do not apply. But its reliability can still be affected by anesthesia depth, monitoring setup and team experience. The goal, he said, is not simply reacting more effectively when signals disappear. It is preventing false alarms from happening in the first place.
For years, spine surgeons have spent valuable time trying to distinguish true neurologic danger from false signals generated by the monitoring system itself. Dr. Saifi’s team is working toward a future where fewer of those decisions are made in uncertainty.
“How do we create a standardized system so that you don’t have a false positive?” he said. For Dr. Saifi, the future of neuromonitoring may be less about generating more data and more about giving surgeons confidence that the data they already have can be trusted.
Because when the difference between a true warning and a false alarm can change the course of an operation, accuracy is not just a technical achievement; it is a patient safety win.
At the Becker’s 32nd Annual Meeting: The Business and Operations of ASCs, taking place October 29-31 in Chicago, ASC leaders, surgeons and healthcare executives will explore strategies to drive growth, enhance operational performance, navigate reimbursement challenges and prepare for the future of ambulatory surgery. Apply for complimentary registration now.
