A Comparison of Visual Outcomes after Gross Total or Subtotal Resection for Giant Pituitary Macroadenomas

Pituitary adenomas represent 10 to 15% of intracranial tumors. The clinical presentation of such tumors may include headaches, visual aberrations, and endocrine disturbances.¹ Contemporary management of functional adenomas, excluding prolactinomas, is well established with gross total resection being the primary goal to attain chemical remission.^2–4 Despite this, treatment of giant macroadenomas which represent only 5 to 14% of surgically treated adenomas remains somewhat controversial.

The treatment paradigm for nonfunctioning adenomas is predicated on surgical decompression of the optic apparatus. The majority of large and giant macroadenomas causing visual symptoms are nonfunctioning.⁵ The best preoperative predictive factor for visual loss has been shown to be tumor size^5,6 and factors related to visual recovery include the degree of optic atrophy, the severity of visual field (VF) defect, and the tumor size.⁶

Since the introduction of endoscopic endonasal transsphenoidal surgery (EETS) postoperative visual outcomes have improved. Despite this there is a discrepancy within the published literature of visual outcomes due to variations in treatment strategy and timing of surgery. A recent meta-analysis showed that while visual field deficits improved after EETS, complete recovery occurred in under half with a small proportion deteriorating.⁷ Despite these outcomes, current dogma encourages aggressive resections at the cost of increased morbidity.

Between 2011 and 2016, more than 200 EETS procedures for pituitary adenomas were performed with up to 5-year follow-up.

A retrospective pre- and postsurgical volumetric analysis was performed for the giant macroadenomas to elucidate completeness of resection. Visual function for these patients was assessed using visual acuity, Humphrey visual fields and OCT. Correlations were then drawn as to the benefit of gross total resection over subtotal resection in terms of improved visual function.

Preliminary analyses suggest subtotal resection of giant macroadenomas may be adequate to decompress the optic apparatus and allow stabilization or improvement in visual function in these large complex tumors.