Coma due to malplaced external ventricular drain.

Ventriculostomy or external ventricular drain (EVD) placement by free-hand technique has a high malplacement rate. It is a blind procedure that often requires multiple attempts and revisions. To date, no neurological complication due to EVD malplacement has been reported in the literature. In this report, we present the first case of coma induced by a malplaced EVD and the patient regained consciousness after the drain was adjusted. Our discussion focused on various techniques that can improve the accuracy of EVD insertion. EVD insertion under image guidance provides better accuracy with limited disadvantages. We hypothesized that the patient's coma was due to the mass effect and irritation of the malplaced EVD exerted onto the ventral periaqueductal grey matter and the ascending neurons from upper brainstem.