How successful is transsphenoidal surgery for nonfunctioning adenomas?
• Transsphenoidal resection: The rates of successful NFA resection are a function of the tumor size and degree of invasiveness. Gross total resection rates are highest for tumors localized exclusively in the sella, but decreases to < 50% when there is cavernous sinus invasion or bony involvement.
• Pituitary hormone function: Transsphenoidal surgery, when performed in experienced neurosurgical centers, maintains normal pituitary gland function in the vast majority of NFA cases when function is normal preoperatively (> 85–90%) and usually improves or normalizes (15%–30%) any preoperative hormone deficiencies. In addition, new-onset pituitary hormone deficiencies, after an uncomplicated TSS, are uncommon at experienced neurosurgical centers (~ 5 to 7%). Patients with pituitary apoplexy, or who underwent repeat aggressive surgical resections, are unlikely to recovery anterior pituitary gland function. Recovery of pituitary hormone production is best assessed at 6 to 12 weeks after surgery. The recommended evaluation includes basal pituitary hormone testing (as stated above) and stimulation testing (e.g., cosyntropin or GH deficiency testing) only as indicated.
• Headaches: Headaches, particularly those associated with a retroorbital tumor location and large tumors (> 1 cm), are relieved in an estimated ≈ 70% of NFA patients postoperatively.
• Vision: Most patients with preoperative vision deficits improve, although many do not normalize entirely (≈ 30% of cases). The time course of visual field recovery includes an immediate improvement in the first week postoperatively (≈ 50%), followed by a slower recovery phase over the next 6 to 12 months. A worse prognosis for visual recovery is associated with a longer duration of preoperative vision loss.