Visual electrophysiology in children with tumours affecting the visual pathway. Case reports.

In 9 children (8-14 years of age) with orbital, suprasellar or postchiasmal tumours, visual loss was studied by visual electrophysiology in relation to ophthalmologic and neuroimaging findings. Pattern electroretinography (PERG) and pattern visual evoked potentials (PVEP) to full and half-field pattern-reversal stimulation were recorded and PERG and PVEP changes were related to the tumour location. PERG wave P50 attenuation was found associated with the central retinal dysfunction in the child with orbital rhabdomyosarcoma; PVEP wave P100 delay was associated with the optic nerve dysfunction in a child with retrobulbar chondrosarcoma and in a child with optic nerve glioma; PVEP wave P100 asymmetry was associated with the crossed fibers dysfunction in a child with hypothalamic germinoma, and PVEP wave P100 uncrossed asymmetry was associated with postchiasmal dysfunction in children with postchiasmal tumours (one with pilocytic astrocytoma and two with angioma). On the other hand, normal PERG suggested that there was no central retinal dysfunction in a child with pleomorphic adenoma of the lacrimal gland, and normal PVEP to full and half-field stimulation excluded visual pathway dysfunction at the chiasm in a child with suprasellar arachnoidal cyst. Follow-up was useful in indicating whether visual dysfunction was progressive or not. We conclude that PERG and PVEP findings contributed to understanding whether the dysfunction originated was at the retina, in the optic nerve, chiasm or postchiasmal pathway.

Anterior communicating artery aneurysm associated with tuberculum sellae meningioma--case report.

A 50-year-old male presented with a very unusual case of a calcified anterior communicating artery (AComA) aneurysm associated with a tuberculum sellae meningioma. Until 10 years previously, the patient had been a professional soccer player for 15 years. He noticed a slight decrease in visual acuity in the right eye 7 years before. The patient was in the care of an oculist throughout this period. Two months before admission, a significant and rapid decrease of vision in the right eye occurred. Computed tomography and magnetic resonance imaging showed a round-shaped, partially calcified tumorous lesion. Four-vessel angiography revealed a large AComA aneurysm. During surgery, a tuberculum sellae. meningioma was found in combination with an AComA aneurysm with a completely calcified wall. The meningioma was resected totally. The AComA aneurysm with a calcified wall could not be clipped or resected and was left alone. His visual deficit improved postoperatively.

Addition of IFN-alpha to treatment of malignant brain tumors.

Despite many attempts to improve the survival after surgery of patients with malignant astrocytoma the prognosis is poor. We have used natural IFN-alpha in 16 patients with malignant astrocytoma treated between 1987 and 1990; 6 for recurrent tumors. Radiation therapy was given in 2 Gy fractions daily to a total dose of 50 Gy in the tumor area, 5 fractions per week and IFN twice per week, cisplatinum 60 mg/m2 i.v. every second week and vincristine 2 mg every week in 12-h i.v. infusions. Eight patients were reoperated when clinical deterioration suggested recurrent tumor; histological examination showed no residual tumor in 7 of them. Of these 8 patients 3 are alive and well, 2 of them after more than 5 years. The study suggests that malignant astrocytoma can be successfully eradicated with surgery, irradiation, IFN-alpha and chemotherapy. The treatment had, however, unacceptably high neurotoxicity. Earlier removal of the tumor necrosis, before clinical deterioration, could possibly diminish the high complication rate and consequently improve survival.

Visual evoked potential abnormalities in chiasmal lesions.

Pattern reversal visual evoked potentials (VEPs) were recorded from 38 patients with lesions affecting the chiasmal area. Lesions were confirmed by computer tomography and all patients had ophthalmologic examination. VEPs to full-field stimulation (0-16 degrees r) were compared with those obtained with half-field stimulation. Changes in VEPs were seen as a nonrecordable or attenuated P 100 (abnormal amplitude ratio) or as a prolonged P 100. Analysis of the records showed that temporal half-field stimulation (crossed fibers) yielded a higher rate of abnormal responses (80%) than full-field stimulation (66%). The most frequent abnormality in the former stimulation was a nonrecordable P 100 (42%) and in the latter an abnormal amplitude ratio of P 100 (41%). When the uncrossed fibers were stimulated with the nasal half-field, abnormalities were detected in 32% of responses. Lesions in the region of the sella turcica were also associated with a high incidence of delayed responses (39% of patients when crossed fibers were stimulated). However, the magnitude of the delays was smaller (1-32 ms) compared with delays in patients with demyelinating disease. Findings of this study show that half-field stimulation assists in the interpretation of responses to full-field stimulation. In addition, half-field stimulation can reveal abnormalities that are not detected with full-field stimulation.

Intratumor application of human leukocyte interferon-alpha in patients with malignant brain tumors.

Seventeen patients with malignant brain tumors have been treated by local application of human leukocyte interferon-alpha (HLI-alpha) in addition to radiation; eight of these patients also received chemotherapy. Twelve patients were treated for primary tumor and five for recurrence. After partial removal (or biopsy), an Ommaya reservoir was placed with its catheter in the tumor cavity, and 3 Gy was given to the whole brain in 2 weeks with a local boost of 1.5 Gy in 1 week. During radiation therapy HLI-alpha (2 x 10(6) U) was given through the Ommaya reservoir two or three times per week. Vincristine (2 mg) was given during radiation therapy weekly and in combination with cisplatin (60-80 mg) every other week. Four patients are alive and well 11, 14, 15, and 30 months after treatment and 5 have died without tumor. The fact that the patients did not survive despite the effective local tumor control suggests that, at least in some of them, degenerative changes in the brain tissue as a result of the combined treatment might have been the cause of death.

A transcavernous-transsellar approach to the basilar tip aneurysms.

A series of 11 patients with a basilar tip aneurysm were treated operatively. The aneurysm had ruptured in all cases and caused at least one haemorrhage prior to surgery. Four patients harboured large aneurysms, while in the rest of them the aneurysms were small in size. In all the 11 patients a modified pterional transcavernous-transsellar approach was used which considerably facilitated clipping and secured complete exclusion of all aneurysms, including the large ones. Eight patients made a complete recovery and resumed their original occupation. One is hemiparetic but capable of self care, one is hemiplegic, and one died after surgery. The purpose of this report is to present our modified surgical approach to basilar tip aneurysms, which provides good exposure of the entire region of the bifurcation of the basilar artery and adjacent blood vessels as far as the anterior inferior cerebellar arteries, and requires but minimal retraction of the brain.