Iatrogenic pseudoaneurysm formation of the anterior cerebral artery following placement of an external ventricular drain: illustrative case.

backgroundExternal ventricular drains (EVDs) provide an invaluable diagnostic method for accessing cerebrospinal fluid and therapeutically treating elevated intracranial pressure. Although complications including hemorrhage and infection have been well documented, the formation of iatrogenic pseudoaneurysms following EVD placement has rarely been reported. The authors present a case of this exceedingly rare complication of iatrogenic pseudoaneurysm formation following EVD placement. OBSERVATIONS: In this report, the authors document the formation of a pseudoaneurysm within the A4 segment of the anterior cerebral artery in a 77-year-old female following frontal EVD placement, which was promptly recognized and successfully embolized endovascularly. They discuss the suspected pathophysiology, given the literature citing similar complications, and the differing management strategies following the discovery of iatrogenic pseudoaneurysms. LESSONS: Although rare, iatrogenic vascular injury following EVD placement or removal should not be overlooked. If hemorrhage following catheter placement or manipulation develops, suspicion for iatrogenic vascular injury should be high, and appropriate vascular imaging should be performed. As reported here, prompt treatment with endovascular embolization provides a safe and effective means to prevent future rupture and worsening hemorrhage. This case and the literature review emphasize the importance of rapid diagnosis of postprocedural pseudoaneurysm formation and treatment to prevent continued secondary brain injury. https://thejns.org/doi/10.3171/CASE24558.