Intracranial-Intracranial Bypass Using a "Y"-Shaped Artery Graft for Growing Unruptured Gemella Morbillorum Infectious Aneurysm on Artery Supplying Sensory Cortex: A Case Report.

ABSTRACT Background Vascular reconstruction is required to treat infectious intracranial aneurysms (IIAs) on arteries supplying the eloquent area. However, extracranial-intracranial bypass is sometimes impossible because IIAs are frequently located distally on arteries and the length of a donor artery is limited. The authors report a rare case of an unruptured Gemella Morbillorum IIA, which was successfully treated by intracranial-intracranial (IC-IC) bypass using a “Y”-shaped superficial temporal artery (STA) interposition graft. Case Description A 52-year-old man presented as heart failure and an unruptured IIA in the right anterior parietal artery due to acute Gemella Morbillorum endocarditis. The patient was treated with urgent replacement of cardiac valves and antibiotic therapy. However, the IIA increased in size during the following one month, and therefore was treated surgically to prevent the rupture. The end-to-side IC-IC bypass using a “Y”-shaped STA graft followed by aneurysmal trapping was performed to overcome the limited length of STA as a donor artery to prevent cerebral ischemia in the artery territory as well as to avoid direct injury to the sensory cortex adhering tightly to the IIA. Postoperative courses were uneventful, and he recovered from the infectious diseases. Conclusions This case suggests that end-to-side IC-IC bypass using a “Y”-shaped STA graft can be a good option for surgical treatment of IIAs, which are located in eloquent areas.