Postoperative ischemic changes after glioma resection identified by diffusion-weighted magnetic resonance imaging and their association with intraoperative motor evoked potentials

Abstract

Object The aim of surgical glioma treatment is the complete resection of tumor tissue while preserving neurological function. Surgery-related neurological deficits arise from direct damage to the cortical or subcortical structures or from ischemia. The authors aimed to assess the incidence of resection-related ischemia of newly diagnosed or recurrent supratentorial gliomas and the sensitivity of intraoperative neuromonitoring (IOM) of motor evoked potentials (MEPs) for detecting such ischemic events and their influence on neurological motor function. Methods Between January 2009 and December 2010, 70 patients with tumors in motor-eloquent brain areas underwent intraoperative MEP monitoring during glioma resection and were examined by early postoperative MRI including diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping. Postoperative areas of restricted diffusion were assessed by investigators blinded to the course of intraoperative MEPs and the neurological course. Results Among the 70 enrolled patients, a MEP amplitude decline below 50% of the baseline level was observed in 21 patients (30%). Sixteen of these patients (76%) had ischemic lesions identified on postoperative MRI scans. Forty-nine patients (70%) showed no decline in MEP amplitude, and only 16 (33%) of these patients harbored ischemic lesions. Moreover, 9 (69%) of 13 patients with a permanent loss of MEP amplitude showed postoperative ischemic lesions. Factors that promoted the occurrence of postoperative infarction were previous radiotherapy and location of the tumor close to the central arteries. Conclusions Alterations in the MEP amplitude during tumor resection and postoperative ischemic lesions are associated with postoperative impairment of motor function. Rather than cortical or subcortical structural damage of eloquent brain tissue alone, peri- or postoperative ischemic lesions play a crucial role in the development of surgery-related motor deficits.

Repeat-surgery at Glioblastoma recurrence, when and why to operate?

“…However, this is only in the early postoperative period [19]. This early postoperative neurological deterioration may be explained by findings from other studies where it was shown that rather than cortical or subcortical structural damage of eloquent brain tissue alone, peri-or postoperative ischemic lesions play a crucial role in the development of surgery-related motor deficits [20]. This suggests that the complication rate at recurrent surgery is irrespective of complications at primary surgery and each surgery has an individual complication risk.…”

Resection of supratentorial gliomas: the need to merge microsurgical technical cornerstones with modern functional mapping concepts. An overview

“…In fact, if large caliber arteries are safely handled, both with or without microsurgical technique, venous trunks and terminal arteries are more prone to rupture or thrombose. Recently, a study reported that postoperative diffusion-weighted MRI indicated that ischemic lesions could account for 30 % of postoperative deficits after surgery for primary gliomas and up to 80 % of deficits in recurrent gliomas [48]. For tumors in the parasagittal area (infiltrating SMA or prerolandic and postrolandic area), the dura must be opened with great care because large bridging veins very often enter the sagittal sinus few millimeters away from the midline, and hence, there is always a risk of cutting them inadvertently.…”

Microsurgical anatomy of the central lobe

“…Gempt et al 20 reported that neurological impairment following glioma resection was more frequently due to ischemic lesions than to cortical or subcortical structural damage. When performing surgeries involving the medial surface of the frontal lobe, care must be taken to avoid coagulating posteriorly directed branches of the pericallosal and callosomarginal arteries.…”