[Transsphenoidal Microneurosurgery. Part 4: Neuroophthalmological cure in pituitary adenoma].

Fifty-nine pituitary adenomas treated with transsphenoidal approach were analyzed in the light of visual field defects and the postoperative cure rates. Twenty-six cases had visual field defects. The majority of the defects were temporal 1/2 or superior 1/4, although atypical deficits such as incongruous homonymous hemianopsia, nasal 1/2 defect, superior 1/2 defect, peripheral constrict were seen. The visual field defects were correlated with the size of the tumor in Hardy and Vezina classification of the suprasellar extension. The visual field defects appeared in 100% of Type C, 89% of Type B, 50% of Type A, 0% of Type O. In 24 out of 26 patients with preoperative visual field defect, the visual field improved either to normal or wider fields postoperatively. There were 9 patients with optic atrophy, which also showed the correlation with the tumor size. Only the tumor of Type B or C revealed optic atrophy but still 45.4% patients in this group had no optic atrophy. The visual field defect in 85% of the patients without optic atrophy improved to normal post-operatively, while 66% with mild and only 20% with severe optic atrophy showed complete recovery. In conclusions, authors emphasize followings. 1) Improvement rate in the visual field defect of pituitary adenomas by transsphenoidal approach was superior to the previously reported rates by transcranial operations. 2) The factors affecting the functional prognosis in the visual field defect are the natures of the tumor, surgical approach and the factors affecting the plasticity of the optic nerves. The existence and degree of optic atrophy could be one of the references for the plasticity of the optic nerves. 3) There is a close relation between the morphological potential of the tumor and optic atrophy/visual field defect. From these standpoints of view, the early diagnosis and treatment should be emphasized.