For most pituitary tumors, surgery remains the first-line treatment of symptomatic pituitary adenomas. Surgery is also chosen secondarily when medical treatment or radiotherapy fails; particularly for prolactin and growth hormone secreting adenomas. Surgery provides prompt relief from excess hormone secretion and mass effect. Surgery is also indicated in pituitary apoplexy with compressive symptoms regardless of the tumor type.

The transsphenoidal approach can be used for 95% of pituitary tumors. Exceptions are those tumors with significant temporal or anterior cranial fossa extension. In such circumstances, transcranial approaches are often necessary. Occasionally, combined transsphenoidal and transcranial approaches are used. Nevertheless, some surgeons extend the basic transsphenoidal exposure in order to remove some of these tumors and avoid a craniotomy (Fig. 3) (24,25,28,47).

The transsphenoidal approach is a versatile method for treating pituitary tumors (Table 4). Endoscopic approaches may be used in isolation or as an adjunct to the other transsphenoidal approaches (Fig. 1) (20-23). Computer-guided neuronavigational techniques are occasionally used in lieu of traditional fluoroscopic guidance (Fig. 2) (9,19). The role of neuronavigation is most pertinent in recurrent adenomas in which the midline anatomy has been distorted by previous transsphenoidal surgery. There are three basic variations of the transsphenoidal approach.

Visual deficits in patients with non-functioning pituitary adenomas are improved in approximately 87%. Some visual deterioration may occur in 4%. Most patients with intact pituitary function preoperatively retain their normal function. Those with preoperative pituitary deficiency regain function in 27% of the cases. The remaining patients are managed with oral hormone replacement therapy. Tumor recurrence is also higher. Ten-year recurrence rates are approximately 16%, although only 6% require additional treatment (Table 5). On long-term follow-up, 83% of patients are alive and well without evidence of disease.

Using strict criteria for remission, transsphenoidal surgery obtains remission in 88% of patients with acromegaly with microadenomas and 65% of those harboring macroadenomas (Table 5). Acromegalic symptoms are improved in 95% and recurrence is less than 2 percent at ten years. Ninety seven percent of patients have preserved normal pituitary function. Seventy-two percent of patients with greater than ten year follow-up, including those with adjunctive therapy, are alive and well without evidence of active disease.

Patients with prolactinomas who present for surgery are most often those who have failed medical management. Prolactin levels are normalized in 87% of microadenomas and 56% of macroadenomas (Table 5). The recurrence rate among those patients who are normalized after a transsphenoidal operation is 13% at ten years. Preserved pituitary function occurs in all but 3%.

Surgical management of Cushing's disease achieves a 91% remission rate for microadenomas, but falls to 65% for those with macroadenomas (Table 5). While twelve percent of adults experience recurrence after ten years, a much higher percentage of children may develop recurrent Cushing's disease. Postoperative stereotactic radiosurgery has achieved remission in approximately 68% of patients whose disease either did not remit following surgery or recurred.

The overall mortality rate for transsphenoidal surgery is less than 0.5% (Table 6). Major morbidity (cerebrospinal fluid leak, meningitis, stroke, intracranial hemorrhage, and visual loss) occurs in between 1 and 2% of cases. Less serious complications (sinus disease, nasal septal perforations, and wound issues) occur in approximately 6.5%. Larger invasive tumors and giant adenomas are associated with a higher morbidity.