Prognostic factors of visual field improvement after trans-sphenoidal approach for pituitary macroadenomas: review of the literature and analysis by quantitative method.

The objective of the study was to evaluate the preoperative visual field defect, the postoperative outcome and the possible prognostic factors in patients with pituitary macroadenoma, using a quantitative method (the mean deviation = MD), and to review the literature. A total of 73 patients, operated trough trans-sphenoidal approach, were selected, and data in single eyes were analysed by calculating the frequency and the degree of postoperative improvement (relative improvement). The visual field defect improved in 95.7% of eyes: The recovery was complete in 48.9% and partial in 46.8%. Multivariate logistic regression showed that factors, independently predictive for complete recovery, were as follows: low preoperative MD absolute value (p = 0.008), low cranio-caudal diameter of tumour (p = 0.02) and young age (p = 0.0001). The mean relative improvement in visual field defect (dMD%) was correlated with the preoperative visual acuity (p = 0.0001) and inversely related with the preoperative MD (p = 0.007) and the age (p = 0.017). The relative improvement was higher in tumours with a smaller cranio-caudal diameter (p = 0.0185). In conclusion, using a quantitative method, we can measure the degree of the postoperative visual field defect improvement. Predictive factors for a complete recovery were good preoperative visual function, young age and low cranio-caudal tumour.