Management of nonfunctioning pituitary adenomas with suprasellar extensions by transsphenoidal microsurgery

We evaluated the feasibility and therapeutic effectiveness of transsphenoidal microsurgical removal of nonfunctioning pituitary adenomas with suprasellar extensions. The diagnostic modes, surgical technique, and outcome were reviewed in 208 patients with pituitary adenomas extending beyond the sella turcica who were treated by transsphenoidal microsurgery. All patients except three presented with significantly diminished visual acuity and visual field defects.

Diagnosis was confirmed by skull X-ray plain films, CT, or MRI scanning. Operations were performed via a transsphenoidal approach under microscope. A subarachnoid catheter was preoperatively inserted in the lumbar cistern, through which saline was slowly injected during operation to increase the intracranial pressure so as to move the suprasellar tumor into the operative field to aid the removal.

In this series, gross total removal of an adenoma in 146 cases (70.2%) and subtotal removal in 50 cases (24.0%) was achieved; partial removal was carried out in the remaining 12 cases (5.8%) of fibrous or dumbbell-shaped adenomas. There were no deaths in this group. Follow-up review (median 3.8 years) in 187 patients revealed that 97.8% of those with preoperative diminished visual acuity had postoperative improvement; 2.2% had no change, and none deteriorated significantly. Among 181 patients with preoperative visual field defects, postoperative improvement was good in 169 (93.4%), and poor in 12 (6.6%). The major complications were diabetes insipidus and cerebrospinal fluid rhinorrhea, which occurred in 13.5% and 4.8% of patients, respectively. The tumors recurred in 12 patients (6.4%) who were considered to have a macroscopically complete removal at surgery. Continuing growth of residual tumors was found in 31 (16.6%) based on visual acuity decrease, visual field defects, and CT or MRI examination. Of the recurrent and residual tumors, 4, 9, 17, and 13 cases belonged to Grades A, B, C, and D, respectively.

Comparison with transfrontal surgery suggests that these results are as good as those of transfrontal procedures and that the incidence of serious side effects is considerably lower. We consider that the microsurgical removal of pituitary tumors by the transsphenoidal approach is safe and effective even in very large or giant adenomas, since it allows rapid and adequate decompression of the optic nerves and chiasm.