Predictability of internal carotid artery (ICA) dissectability in cases showing ICA involvement in parasellar meningioma.

The present study identified predictors for surgical internal carotid artery (ICA) dissection in cases showing ICA involvement in parasellar meningiomas. Twelve cases encountered over the past 4 years were reviewed. Based on MRI findings, patients were divided into two groups; six patients demonstrated complete ICA involvement (encasement) and the other six showed partial ICA involvement (engulfment). The ICA was dissected in all cases in the engulfment group and in four of six cases in the encasement group. The ICA can be dissected even if it is involved at the centre of the tumour if the tumour is soft and can be aspirated. Preservation of the perforating arteries is more important and more difficult. Angiographic finding showing encasement of a long segment of the ICA is unfavourable because of the high possibility that the perforating arteries are involved. Local stenosis of ICA is another unfavourable finding for surgical dissection because tumour invasion of the arterial wall would be suspected. Thus, ICA encasement by the tumour is the less favourable finding for surgery but it is not a decisive predictor. More important findings for ICA dissection in cases showing ICA encasement are involvement of a long segment of the ICA and local ICA stenosis on angiogram.