Factors Affecting Visual Outcomes after Transsphenoidal Pituitary Adenectomy

Abstract Background: Pituitary tumoursare considered to be about 10-15% of all brain tumours, of which 9% are the adenomas, which are classified by size and ability to secrete hormones or not. Most commonly non-functional pituitary adenomas and less commonly functional pituitary adenomas present with visual disturbances due to optic chiasm compression over time. The most commonly expressed visual field pattern is the bitemporal hemianopia. Optic nerve damage resulting from compression by the adenoma caused by direct interruption of axonal conduction, impairment of axonal flow, demyelination and ischaemia. These arereversible at first but over time, they may be permanent. This thesis aims for studying the different factors affecting the visual outcomes after endonasal transsphenoidal pituitary adenectomy and thereby deducing an array of prognostic factors to make a basic forecast of the postoperative visual outcomes. Aim of Study: To determine the factors that could affect the prognosis of transsphenoidal pituitary adenectomy and its effect on the outcome of vision. Patients and Methods: This is a prospective observational study of 15 cases of pituitary adenomas (secretory and non-secretory) treated via an endonasal transsphenoidal pituitary adenectomy at Kasr Al-Ainy University Hospitals and Nasser Institute Hospital. Preoperatively, all cased studied patients underwent evaluation by best-corrected visual acuity (BCVA), visual field by confrontation test, dilated fundus examination, slit-lamp bio microscopy and automated perimetry. Visual Impairment scoring (VIS), developed by the German Ophthal-mological Society, was thereby assessed for all patients. All patients underwent endoscopic transsphenoidal pituitary adenectomy. Postoperative perimetry and postoperative visual acuity were done one month postoperatively to discern the outcome of this study. Visual impairment scoring was done again on all patients. Results: This study comprised 15 cases, 8 males and 7 females, ages ranged from 22 to 61 years (mean age 41 years).
Of the 15 cases, 13 cases were non-functioning tumours, 1 acromegalic patient and 1 Cushing's disease who were all operated upon by endoscopic endonasal transsphenoidal approach. Poorer postoperative visual outcomes were seen in patients with duration of symptoms >8ms, tumour vertical size >3cm, tumour volume >6.8cm3, sagittal optic chiasm displacement >22.5mm and coronal optic chiasm displacement >22mm. Conclusion: In conclusion, different factors as duration of symptoms, tumoursize, tumour volume and optic chiasm dis-placement inversely affect the visual outcome postoperatively as they increase in magnitude. The most significant of all was the optic chiasm displacement with a direct involvement in the affection of visual health, which makes it the most powerful prognostic factor with a higher degree of significance over the tumour dimensions (tumour vertical size and tumour volume).