Optic chiasm astrocytomas of childhood. 2. Surgical management

We presented our experience from 1975 to 1994 with emphasis on the long term follow-up of children with optic chiasm astrocytomas in part I. In part II we describe the surgical management of 20 patients with the diagnosis of an astrocytoma of the optic chiasm confirmed by biopsy. These patients underwent surgery by the senior author between 1988 and 1994. The patients and the tumors in this series are comparable in age, sex, and presentation and imaging characteristics to other series. Surgery was undertaken with the intent to reduce tumor volume and mass effect and in certain cases to confirm the diagnosis. The patients' mean age at the time of surgery was 81 (range 18-216) months. The surgical approaches used were pterional in 11 patients, transorbital/subfrontal in 8, and subfrontal in 1 patient. Greater than 50% of the tumor was resected in 8 patients, less than 50% was resected in 9, and biopsy only was achieved in 3 patients. Larger tumors were more likely to have magnetic resonance imaging documented debulking of tumor. Permanent morbidity included mild visual loss, diabetes insipidus, mild hemiparesis, and panhypopituitarism in 1 patient each. There was no surgical mortality. The likelihood of resecting greater than 50% of the tumor was higher in those with a diameter greater than 25 mm. The indications for craniotomy are (1) to debulk symptomatic tumors greater than 50 mm in diameter which are exophytic or cystic; (2) to relieve obstruction at the foramen of Monro, and (3) for diagnostic biopsy.