Heavily T2 weighted MR assessment of fornical injury after anterior interhemispheric approach for large suprasellar tumors

Fornical injury in transforaminal approach is well known. Its injury in the anterior interhemispheric approach (AIA) has been rarely highlighted. We r eport 2 cases with a large suprasellar tumor who underwent AIA. Postoperati ve heavily T2 weighted reversed (T2R) MR images demonstrated its unilateral injury. The clinical significance of symptom-free fornical injury after AI A is discussed. Cases 1 and 2 were a 15 year-old girl with a meningioma and a 49-year-old w oman with a craniopharyngioma, respectively. They underwent AIA. Postoperat ive T2R images revealed unilateral fornical crus atrophy. They did not pres ent associated memory deficits. Case I had the injury of both fornical colu mn and anterior commissure. They were speculatively torn by intra-operative lateral retraction of the frontal lobes. Case 2 had unilateral atrophy of the mammillary body and postcommissural fornix, which were probably caused by ischemic damage related to surgical manipulation, since case 2 had an as sociated anterior thalamic infarct. During the operation for large suprasellar tumors, excessive laterally dire cted brain retraction should be avoided, since such manipulation may easily tear the overstretched anterior commissure and fornical column. Once we no tice or suspect fornical injury on MR studies in cases of re-operation, we have to choose a surgical approach and operative manipulation to preserve a n intact fornix. The MR evaluation of fornix should be included in the perioperative radiolo gical assessment, since patients with unilateral fornical injury were free of memory disturbance, and T2R imaging is a useful MR sequence for depictin g the anatomy related to the fornix.