Early detection of cerebral ischemic events on intraoperative magnetic resonance imaging during surgical procedures for deep brain stimulation.

BACKGROUND

Although intracerebral hemorrhage is the most feared complication of deep brain stimulation (DBS) surgery, cerebral ischemic events in association with DBS surgery have only rarely been described. We therefore evaluated the role of intraoperative MRI (iMRI) for early identification of cerebral ischemic events during DBS procedures and determined how ischemic infarctions affect patients over acute and long-term periods.

METHODS

Between January 2010 and December 2017, 1160 DBS electrodes were implanted in 595 patients at Chinese People's Liberation Army General Hospital, with the help of iMRI. The iMRI was performed in all patients after implantation, to define the accuracy of lead placement and detect complications. A CT scan was performed on postoperative days 1 to 7.

RESULTS

The iMRI showed that cerebral ischemic changes happened in nine (1.51% of patients, 0.78% of leads) patients. Only two (0.34%) of nine patients had an ischemic infarction in the basal ganglia, while seven (1.18%) had cortical ischemia. Six (67%) of the nine patients had long-term complications, two with mild hemiparesis, two with seizures, one with language dysfunction, and one with memory loss. Of those with a cortical ischemic infarction, only three (42.86%) of seven patients had no long-term complications. Long-term follow-up imaging showed that not all the patients recovered normal morphological structure in the area of ischemic foci. The factors of sex, age, target, and anesthesia were not related to ischemic events. In six (66.7%) cases, the entry point on the cortex or the path was not ideal.

CONCLUSIONS

Intraoperative ischemic events are not uncommon in DBS surgery. Ischemia can cause serious permanent complications, and regions subject to severe ischemia cannot be restored; it is therefore necessary to pay careful attention to any signs of ischemia. iMRI objectively provides the basis for early diagnosis of intraoperative ischemic infarction, providing guidance for follow-up treatment. The deviation in the entry point on the cortex or in the path resulted in vascular injury; it may be the key cause of ischemic events during DBS procedures.