Pterional keyhole approach to middle cerebral artery aneurysms through an outer canthal skin incision.

OBJECT: The supraorbital keyhole approach via an eyebrow skin incision provides a method for the minimally invasive clipping of aneurysms located in the circle of Willis, but has disadvantages for aneurysms located in the lateral Sylvian fissure. The pterional keyhole minicraniotomy via an outer canthal skin incision is proposed for the clipping of unruptured aneurysms of the middle cerebral artery (MCA). METHODS: The procedure consists of a 35-mm outer canthal skin incision, partial temporal muscle dissection restricted in the pterion, a 20-25-mm keyhole minicraniotomy, and a 15-20-mm dural incision to expose the lateral Sylvian fissure. Twenty keyhole clipping procedures were performed in 20 patients with unruptured MCA aneurysms. RESULTS: Only one patient showed a temporary mild hemiparesis (reversible ischemic neurological deficit) due to lacunar infarction. No shaving of scalp hair, drain placement, or anticonvulsant drug administration were required. Most patients were discharged on the 2nd or 3rd postoperative day. One patient showed a weakness of the frontalis muscle, but this complication was eliminated by the definition of a safety zone to avoid damage to the frontal branch of the facial nerve. CONCLUSIONS: The pterional keyhole approach via outer an canthal skin incision is another treatment option for relatively small, unruptured MCA aneurysms.