Endonasal Transsphenoidal Resection of Nonfunctioning Pituitary Adenomas: A Retrospective Single Center Series of 411 Patients

Background/Objective: Surgical resection is widely accepted as the standard of care for treating symptomatic nonfunctional pituitary adenomas (NFPAs), typically via a transsphenoidal approach. This study evaluated long term surgical outcomes following resection of NFPAs at a major tertiary academic pituitary center.

Methods: A retrospective chart review of 411 patients who underwent transsphenoidal resection of an NFPA at two University of Southern California affiliated locations (Keck Hospital and LAC+USC Medical Center) between 1992–2015 was conducted. Inclusion criteria were patients aged ≥18 years who underwent transsphenoidal resection of an NFPA, with minimum 18 months follow-up time. Patient demographics, preoperative symptoms, neuro-imaging results, tumor immunostaining, extent of resection, post-operative complications, and tumor recurrence/progression were all recorded.

Results: Mean patient age was 57.5 years old, with 53.5% male, and a mean follow-up time of 51 months (range 19–235 months). The most common preoperative symptoms were vision loss (55.0%) and headache (37.2%), with 19% (78 patients) of the tumors found incidentally. Preoperative hypothyroidism (20.4%) was the most common form of pituitary-axis dysfunction. Pathologically, positive immunostaining for α-subunit (58.9%), luteinizing hormone (47.7%) and follicular stimulating hormone (21.2%) were most commonly observed. Gross total resection was achieved in 276 patients (67.2%), with subtotal resection in the remaining 135 (32.8%) patients, being mostly associated with cavernous sinus invasion. There were no deaths. The two most common postoperative complications were transient DI and delayed symptomatic hyponatremia (5.84% each). The postoperative CSF leak rate was 2.68%.

Conclusion: This retrospective study supports the primary role for endonasal transsphenoidal resection of NFPAs, with high rates of patient safety and degree of tumor resection. A majority of complications were transient, with no deaths occurring in this series. This study represents a large, single institution experience and serves as an update in the surgical treatment and long-term outcomes following endonasal resection of NFPAs.