Transsphenoidal surgery using a high definition video telescope for pituitary adenomas in dogs with pituitary dependent hypercortisolism: methods and results.

Objective: To (1) establish a technique for transsphenoidal removal of pituitary adenomas in dogs with pituitary dependent hypercortisolism (PDH) using a high definition video telescope, and (2) report initial outcomes.

Study Design: Prospective case series.

Animals: Dogs with pituitary dependent hypercortisolism (PDH; n = 26) with suprasellar masses.

Methods: Pituitary tumors were removed using a modification of a transoral transsphenoidal approach. Surgery was observed using a high definition video telescope (VITOM™) and localization of the sella was performed by drilling pilot holes in the basisphenoid bone followed by computed tomography (CT).

Results: Dogs had PDH confirmed by urinary cortisol to creatinine ratio (UCCR) and endogenous ACTH assays, and tumors confirmed by MRI. There were no postoperative cerebrospinal fluid leaks, wound dehiscence, or surgical site infections. Overall postoperative mortality was 19% with no mortality observed in the last 16 dogs, indicating an initial "learning curve" followed by good surgical results. All dogs that survived the immediate postoperative period (1 week) returned to their owners in good health, on hormonal replacement therapy. Follow-up ranged from 3 to 36 months. Sustained tumor control and hormonal remission based on normalized ACTH and UCCR measurements were observed in 20/21 (95%) dogs at 1-year follow-up.

Conclusions: Modifications of a trans-oral transsphenoidal technique for surgical removal of pituitary tumors provides a safe and effective strategy for long-term remission of PDH with acceptable morbidity and mortality.