Delayed visual deterioration after surgery for pituitary adenoma.

Despite its description in the literature there remains uncertainty about the incidence, the pathophysiological basis and the best management of a delayed visual deterioration in the presence of an empty sella after surgery for pituitary adenomas. Out of a series of 501 patients with pituitary adenomas operated on at our institution between 1984 and 1996, four patients (0.8%) developed a worsening of their visual function 3 to 37 months after surgery in the absence of tumour recurrence. None of the patients had received radiotherapy. Magnetic resonance imaging (MRI) ruled out compression by tumour and showed herniation of suprasellar structures into an empty sella. In three cases re-operation by a subfrontal approach with freeing of the optic structures from tethering scar tissue led to an improvement of visual deficits. In one case a spontaneous recovery was initiated by a minor head injury. Although apparently a rare event, our cases provide evidence for the occurrence of a potentially reversible delayed deterioration of visual function after surgery for pituitary adenomas. Based on our operative findings and our outcome we recommend re-operation by a transcranial approach in patients in whom repeated ophthalmological testing does not show spontaneous improvement within a short period of time.