A Factorial Analysis on Visual Outcomes of Transsphenoidal Surgery for Pituitary Macroadenoma

Objective Sellar lesions are possible reversible causes of vision loss. This study is to provide quantitative objective measurement of efficacy of surgery for non-functioning pituitary adenoma and discuss different factors that could affect visual outcome of non-functioning pituitary adenoma. Method This is a single centre, retrospective study conducted at a tertiary neurosurgery referral centre. 108 cases of sellar tumors which underwent surgery during the 3-year period from early June 2015 to late May 2018 were reviewed. Pituitary adenoma that were non-functioning and without apoplexy at initial presentation were selected for the study. We have analyzed the correlation of different factors with the visual outcome, including the extent of vertical decompression in terms of change in tumor height post operation and the extent of lateral decompression in terms of change in Knosp grading. Visual outcome was represented by the visual impairment score (VIS), an integrated measurement of visual acuity and visual field deficit. Results Preoperative absolute tumor height and supracarotid height correlated with preoperative VIS scale ( p ≤ 0.01). Absolute Knosp grading correlates significantly with VA ( p = 0.001) and VF ( p ≤ 0.001) of that particular eye. Although most patients had an objective improvement in visual acuity (VA) (88%) and visual field (VF) (99%) after operation, a larger reduction in tumor height and successful Knosp downgrading after surgery is associated with better VIS improvement. ( p = 0.025) Change in supracarotid height shows trend in correlating with change in VIS ( p = 0.084). Conclusion Height of tumor measured from genu of cavernous ICA correlates better with visual outcome than absolute tumor height. The extent of both vertical and lateral decompression of non-functioning pituitary adenoma are important determinants that lead to better visual outcome. As endoscopic approach is able to achieve a greater degree of lateral decompression, it is a preferred approach in pituitary surgery to achieve a better visual outcome.