Scoliosis surgery is safer than it has ever been, and many will say a big reason for this is the widespread adoption of intraoperative neuromonitoring (IONM). Paradoxically, though, there has been little actual evidence to back up this belief — that is, until now.

A new study, published in the Canadian Journal of Anesthesia, reports a significantly lower incidence of nerve injury during idiopathic scoliosis correction when performed with IONM rather than without.

Correcting idiopathic scoliosis is a complex and major surgery that involves major spinal alignment changes as well as bone removal and hardware installation. Inherently, the procedure puts the spinal cord and nerve roots at risk.

As recently as 1984, up to 17 percent of these surgical cases resulted in neurological injury. For this reason, surgeons routinely woke patients mid-surgery to monitor their spinal cord function, using what’s called the Stagnara wake-up test.

This test is still used today but is being replaced by the use of continuous monitoring with IONM. While this requires more equipment and trained professionals in the operating room, IONM delivers real-time feedback and has been considered a safer option.

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The wake-up test puts more stress on the patient during surgery and only provides a snapshot of the nervous system. It’s no wonder the use of IONM has flourished — so much so, in fact, that today there are far more jobs than techs can fill.

As the use of IONM has grown, nerve injuries during scoliosis surgery have dropped considerably. A study published in 2020 reported a nerve injury rate of just 0.35 percen, compared with 17 percent in 1984.

While this may seem like an obvious connection, little evidence has been gathered linking the use of IONM with this reduction in nerve injuries. For this reason, researchers from multiple institutions across Canada collaborated on a study examing new nerve injuries and comparing IONM and the Stagnara wake-up test.

They reviewed the cases of 547 patients, ages 10 to 18, who underwent scoliosis correction surgery. More than 60 percent of the cases were performed using IONM and the rest underwent the wake-up test.

The use of IONM was “associated with a reduced overall incidence of NNDs [new neurologic deficits] in idiopathic scoliosis correction,” they concluded.

A review of this research, published in September 2021 by the Canadian Anesthesiologists’ Society, points to a number of limitations of this study, including its small sample size. Nonetheless, “given the paucity of evidence describing the role of neurologic monitoring and neurologic outcomes in spine surgery, the authors should be commended for undertaking this study and sharing their experience.”

If you want to learn more about the role neurodiagnostic technologists play in the growing field of IONM, read our past posts: