Delayed visual deterioration after surgery for pituitary adenoma

Despite its description in the literature there remains uncertainty about t he incidence, the pathophysiological basis and the best management of a del ayed visual deterioration in the presence of an empty sella after surgery f or pituitary adenomas. Out of a series of 501 patients with pituitary adeno mas 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 sur gery in the absence of tumour recurrence. None of the patients had received radiotherapy. Magnetic resonance imaging (MRI) ruled out compression by tu mour and showed herniation of suprasellar structures into an empty sella. I n three cases re-operation by a subfrontal approach with freeing of the opt ic structures from tethering scar tissue led to an improvement of visual de ficits. In one case a spontaneous recovery was initiated by a minor head in jury. Although apparently a rare event, our cases provide evidence for the occurrence of a potentially reversible delayed deterioration of visual func tion after surgery for pituitary adenomas. Based on our operative findings and our outcome we recommend re-operation by a transcranial approach in pat ients in whom repeated ophthalmological testing does not show spontaneous i mprovement within a short period of time.