042. Intraoperative MRI to assess gross total resection of pediatric vascular malformations: a multicenter experience.

Authors: Ryan James Jafrani, MD

The goal of surgery in arteriovenous malformation (AVM) and cavernous malformation (CM; AVM+CM=VM) is gross total resection (GTR) to minimize hemorrhage risk. Neuronavigation, intraoperative angiography, and ultrasound are useful adjuncts, but have their limitations. Intraoperative MRI (iMRI) provides the excellent spatial and anatomic detail neuronavigation does, while being able to adjust for anatomic changes in real-time similar to ultrasound. Additionally, it is noninvasive and useful in CM, unlike angiography.Methods: The IMRIS Multicenter iMRI Neurosurgery Database (I-MIND) was used to retrospectively identify children who underwent iMRI during VM resection. Demographics, iMRI scans, OR data, complications, and follow-up were recorded.
63 children underwent iMRI during resection of AVM (n=25, 39.7%) or CM (n=38, 60.3%) at 5 institutions by 8 surgeons from 2007-2021. Median age was 12 years (range 1-18 years). Initial iMRI scan indicated GTR in 49 (77.8%) and residual in 14 (22.2%). 11 (17.5%, 4 AVMs, 8 CMs) underwent additional resection leading to GTR, while 3 (2 AVMs, 1 CM) were left with known residual because of risk of removal (2) or risk of continued surgery (1). In total, 60/63 patients (95.2%; 97.4% CMs, 92.0% AVMs) had GTR with the aid of iMRI. There were no iMRI related complications. There was one wound infection and 2 postoperative hemorrhages, one of which was a patient with known residual AVM left due to intraoperative coagulopathy. Average operative time was 4.7±1.8 hours and total OR time was 6.8±2.0 hours.
iMRI is not only safe but efficacious in ensuring a GTR in VM, with 97.4% of CMs and 92.0% of AVMs achieving GTR at time of surgery. An additional 11 patients (17.5%) were felt to have had a GTR that potentially would not have if iMRI had not been available. Long-term outcome data in this cohort is still needed to delineate its true clinical impact.