Sphenoid Ridge Keyhole Approach Using the Lone Star Retractor System in Clipping of Unruptured Middle Cerebral Artery Aneurysms: Technical Note

Abstract

We report a technique for the sphenoid ridge keyhole approach using the Lone Star (LS) retractor system as an extracranial tissue retractor in microsurgical clipping of unruptured middle cerebral artery aneurysms. The LS retractor system is used as the extracranial tissue retractor. A skin incision (50-60 mm) without shaving is made. The temporal fascia is cut, and skin and fascia flap are reflected anteriorly. On the temporal muscle, keyhole craniotomy is registered using the navigation system such that the lateral edge of the sphenoid ridge is the center of the craniotomy. After the temporal muscle is split in the direction of the muscle fiber, keyhole craniotomy of approximately 30 mm in diameter is created. After dural incision, the Sylvian fissure is dissected by a standard microsurgical technique using brain retractors, and the target aneurysm is clipped. By precise registration of the sphenoid ridge keyhole craniotomy, the Sylvian fissure emerged in the center of the keyhole. Using the LS retractor system, a flat and shallow operative field was obtained. There were no complications using this method. We optimized the craniotomy, manipulating the target aneurysm in the center of the keyhole. It did not interfere with conventional microsurgical techniques.