Epidemiology of ischemic lesions after diffuse low-grade glioma resection: a Scandinavian multicenter study

Iatrogenic ischemic injury is believed to be one of the major causes of postoperative neurological deterioration after resection for diffuse low-grade glioma (dLGG). Epidemiological data on ischemic injury following glioma surgery are limited. The aim of this study was to explore the incidence of postoperative ischemia in a population-based cohort and investigate any correlation with postoperative neurological deterioration.

In this retrospective study, ischemic lesions following dLGG resections, performed at 9 hospitals in Sweden and Norway between 2012 and 2017, were identified on diffusion-weighted MRI and volumetrically segmented. The association between the incidence, size, or type of ischemic lesion (rim lesions, limited to the resection border, or sector lesions, extending further into the brain tissue) and postoperative neurological deficits was analyzed.

A total of 286 patients were eligible for study inclusion. A postoperative ischemic lesion was found in 245 (85.7%) cases. In 87 (30.4%) patients, lesions were classified as the rim type; 158 (55.2%) patients had the sector type. Larger ischemic lesions were observed among patients with permanent major deficits (4.2 vs 1.6 cm3, p = 0.022). Sector-shaped ischemic lesions were more often associated with transient neurological deterioration than the rim lesions. The use of advanced imaging, intraoperative monitoring, or other specific neurosurgical techniques and tools did not affect the incidence of ischemic lesions.

The authors found postoperative ischemic lesions to be common after the resection of dLGG. Large and sector-shaped, but not rim-shaped, lesions were associated with measured postoperative neurological deficits. Preventing or limiting the extent of these ischemic injuries is important for improving functional results in dLGG surgery.