Surgical treatment of distal extracranial internal carotid artery aneurysms involving the base of the skull - a multidisciplinary approach.

Introduction is carefully monitored for neurological signs and hemispheric blood flow is measured using SPECT. The surgical procedure is performed using neuroAneurysms of the extracranial internal carotid artery protective technology including moderate hypo(ICA) are uncommon. The most frequent aetiology is thermia (33 °C), mannitol and barbiturate adatherosclerosis, most often affecting the bifurcation of ministration. The surgical strategy aims at excluding the common carotid artery, whereas spontaneous or the aneurysm from the circulation and re-establishing post-traumatic dissection mainly affect the distal pordistal flow to the brain. Exposure of the intrapetrosal tion of the ICA. These lesions usually present with part of the ICA allows access to normal artery wall symptoms of transient ischaemic attacks from emboli, distal to the aneurysm. cranial nerve dysfunction or local expansion. Rupture An incision in the neck, made along the anterior with haemorrhage is rare. margin of the sternocleidomastoid muscle is extended The main indications for operative treatment are retroauricularily, sometimes continuing into a cranicranial nerve deficits and preventive surgery for cataotomy incision. The bifurcation of the common carotid strophic embolic complications. Surgical treatment of artery is exposed and secured. the most distal aneurysms, involving the base of the Continuous monitoring of the facial nerve is used skull, is a challenge, due to the difficulty of exposure during the operation to avoid traumatization. A maof the distal ICA without interference with nearby stoidectomy is performed, including posterior tymstructures and re-establishment of arterial continuity. panotomy with skeletonising of the vertical segment This report summarises the surgical experience with of the facial canal. The tip of the mastoid is reflected these lesions where a multidisciplinary team consisting posteriorly together with the sternomastoid muscle. of neurosurgeon, otological surgeon and vascular surThe tympanic bone under the ear canal is removed by geon is involved. drilling, exposing the jugular foramen and the carotid canal. The inferior portion of the bony external ear canal is removed using reciprocating saw. The ear Operative Technique canal skin and the lower portion of the tympanic membrane are folded upward, maintaining the ossicles Preoperative investigations include CT of the neck, is situ. Facial nerve dissection is extended along the aorto-cervical arteriogram and selective ICA arperipheral part of the nerve into the parotid gland, teriogram. The tolerance for peroperative temporary and the nerve is transposed anteriorly. The carotid canal is opened widely by further drilling, exposing ICA clamping is assessed preoperatively by balloon the intrapetrosal carotid artery. A complete removal occlusion of the ICA. During this procedure the patient of the ear canal and the middle ear together with exenteration of the bony part of the Eustachian tube widens the exposure in patients with narrow ana∗ Please address all correspondence to: T. Skau, Department of Vascular Surgery, University Hospital, S-581 85 Linkoping, Sweden. tomical conditions.