When Should Preoperative Neuromonitoring for Adolescent Idiopathic Scoliosis Be Used?

Adolescent idiopathic scoliosis (AIS) is a coronal curvature of the spine that affects 1 to 3% of adolescents. Of these, a very small percentage – at most 0.5% – progress to the point of needing surgical correction.

Two tools are sometimes used preoperatively to determine the presence of transpinal pathology:  somatosensory evoked potentials (SSEPs) and transcranial magnetic stimulation (TMS). However, their importance and role of preoperative measurement remained unclear. To clarify the role of these tests in the preoperative care of patients with AIS, researchers at Nationwide Children’s Hospital performed a review of medical charts from 2010 to 2012.

The study was recently published in the International Journal of Spine Surgery.

“We wanted to find out if the clinical course of patients with AIS was affected by obtaining these preoperative neuromonitoring results,” says Dr. Walter (Quincy) Samora, MD, orthopedic surgeon at Nationwide Children’s and senior author on the study. “We were noticing that we were able to effectively monitor our patients on the day of surgery without issues, and it seemed that the preoperative tests were not necessary.”

The study included 81 patients, 10 who had abnormal SSEP/TMS results. However, no changes were found in protocol during intraoperative neuromonitoring based on these preoperative findings. Furthermore, the researchers found no correlation between Cobb angle and abnormal preoperative neuromonitoring.

“Our findings don’t show a significant benefit from preoperative measurement of SSEP/TMS,” says Dr. Samora. “The exams did not impact the clinical course for any of our patients with AIS.”

SSEP results can fluctuate based on many factors, which makes preoperative and intraoperative comparisons difficult.

“Knowing that blood pressure, room temperature, and anesthetic can all influence SSEP measurements, it’s far better to take a baseline in the operating room, which will be much more useful for comparing intraoperative measurements,” says Dr. Samora.

The study is in agreement with two other studies showing that SSEP/TMS did not affect the clinical course for patients with AIS who needed surgical intervention.

“The evidence is really in favor of not obtaining preoperative SSEP or TMS measurements for these patients,” Dr. Samora says. “We can save the patients and their families this step in the process and remain confident in our clinical course.”

Reference:

Virk S, Klamar J, Beebe A, Ghosh D, Samora W. The utility of preoperative neuromonitoring for adolescent idiopathic scoliosis. International Journal of Spine Surgery. 2019 Aug 31;13(4):317-320.