In this in situ bypass technique, a side-to-side anastomosis of the arteries distal and adjacent to the aneurysm is achieved. The advantages of this method include avoiding the radial artery as the donor artery and subsequent cervical incision, achieving complete restoration of the skull bone flap, and obtaining a similar diameter between the donor and recipient arteries. This procedure is suitable for treating large or giant middle cerebral artery (MCA) aneurysms that are not viable for coiling or clipping.