‘Inevitable’ ioMRI increases brain-tumor procedure times

Intraoperative MRI (ioMRI) soon may be must-have technology for many if not most neurosurgical suites, but those looking to take the plunge for their brain-tumor service line should expect longer procedure times and more scrupulous pre-operative room preparation.

The longer times will owe mainly to patient positioning and the extra caution to check-listing for things like magnet-safe OR supplies and equipment, according to a study published online Aug. 12 in Clinical Radiology.

Corresponding author Karina Castellon-Larios, MD, of Ohio State University and colleagues conducted a prospective study of 159 neurosurgery procedures performed at Cruces University Hospital in Bizkai, Spain.

ioMRI was used in 109 of the cases (Medtronic’s low-field Polestar M-30 system), while 50 patients who did not have the ioMRI made up the control group.

The procedures included glioma (35.77 percent), pituitary adenoma (24.77 percent) and meningioma resection (16.51 percent), along with various biopsies, metastasis resections and drainages for brain abscess.

The researchers found no statistical significant differences when they compared anesthetic time with surgical time. However, there was a notable difference in duration of patient positioning and total duration of the procedure.

The team recorded mean times as follows:

  • Anesthetic time increased from a mean of 78 minutes without ioMRI to 84 with.
  • Patient positioning increased from 30 minutes without ioMRI to 88 with.
  • Surgical time increased from 276 minutes without ioMRI to 284 with.
  • Total time increased from 387 minutes without ioMRI to 458 minutes with.

In addition, the authors note, the use of ioMRI influenced all cases as regards choice of anesthetic material and/or monitoring devices.

Pointing to this finding, they write in their discussion that personnel who will be daily working with the technology in these settings should have proper training on safety in the MRI environment.

They also recommend the use of a checklist to minimize risks without slowing down procedures any more than necessary.

The team, which was made up of seven anesthesiologists and a neurosurgeon, further stress that ORs need to be equipped with “MR-safe” or “MR-conditional” equipment.

“The anesthesia equipment has to be able to be modified to allow head access during image acquisition,” write Castellon-Larios and colleagues. “Careful positioning of the patient in the ioMRI machine is important to reduce complications due to poor monitoring capability.”

The integration of ioMRI to the neurosurgical setting “seems inevitable,” they add, “and although it provides many advantages, anesthesia delivery is challenging because of the limitations, risks and demands around the MRI machine.”

The study focused on how ioMRI impacts the day-to-day running of a neuroscurgical suite and so did not look at clinical outcomes.