The use of endoscopic transsphenoidal butterfly for pituitary tumors and other saddle area disorders has progressed considerably over the past 20 years. This technique has not only allowed for improved illumination of the surgical field, but has also provided a good view of the surgery. Non-functioning pituitary adenomas are already very large by the time clinical symptoms appear and often invade the suprasellar and cavernous sinuses, and the use of endoscopy offers the possibility of removing these tumors.
There have been many reports of early tumor recurrence and complications after endoscopic transsphenoidal resection of pituitary macroadenomas, but the long-term outcome of endoscopic treatment of pituitary macroadenomas is unclear. Dr. Robert, of the University of Virginia, analyzed the long-term outcomes of endoscopic transnasal butterfly treatment of pituitary macroadenomas in a retrospective study published in a recent issue of Neurosurgery.
The study reviewed 80 patients without functional pituitary macroadenoma treated with endoscopic transnasal butterfly at the University of Virginia between September 2004 and August 2008. All patients were followed for >5 years postoperatively, and data were collected clinically on patient general condition, tumor size, intraoperative findings, postoperative imaging findings, and postoperative endocrine changes.
Forty-two female and 38 male patients with a mean age of 56.6 years were included in the study; the mean follow-up period was 72 months; 31% had visual impairment as the first symptom, 20% had endocrine changes, 16% had headache, 18% had incidental findings, and 11% presented with pituitary stroke. The size of the tumor ranged from 1-3.5 cm. 52% of patients had visual impairment, usually bilateral temporal hemianopia, and 10% had other cranial nerve injuries. The imaging suggests that 69% of the patients had cross-visual compression; pituitary tumors were graded by Knosp, with 25% grade 1, 30% grade 2, and 24% grade 3. The mean tumor volume was 8.0±7.9 cm3, with 73% of patients having tumors less than 10 cm3. After 1 year of follow-up, MRI showed complete resection of the tumor in 71% of patients and residual tumor in 29% of patients. Similarly, tumors less than 3 cm in diameter and less than 10 cm3 in size were more likely to be completely resected than tumors larger than 3 cm in diameter and larger than 10 cm3 in size.
Of the 17 patients with tumor recurrence, 6 were first-time total resection patients and 11 were subtotal resection patients. Of the 23 patients who underwent subtotal resection, 48% had more than 90%, 17% had 80%-90%, 26% had 50%-80%, and only 9% had less than 50% of the tumors resected.
In the patients with total tumor resection, tumor recurrence was found in 7 patients at 1 year follow-up, but none of these patients had visual changes, and the average time to recurrence was 53 months after the initial surgery. Of the 23 patients who underwent subtotal resection, 5 patients underwent resection of the residual tumor after 12 months; the other 18 patients were closely followed up with neurological physical and imaging examinations. Overall, of the 23 patients who underwent subtotal resection, 12 patients showed progression on imaging and 11 showed no significant change on imaging at follow-up. The mean time to tumor progression among subtotal resection patients was 36 months.
Univariate analysis found that factors predictive of tumor recurrence included preoperative operative field absence, tumor characteristics (Knosp grading and aggressiveness). Progression-free survival was significantly longer in patients with Knosp grade 0-2 than in those with grade 3-4, with 97.8%, 88.4%, and 79.5% progression-free survival at 5, 6, and 7 years for patients with Knosp grade 0-2, compared with 63.7% and 54.5% for those with grade 3-4, respectively. 63.7, 54.5, and 54.5 percent, respectively.
Patients who underwent total resection had significantly longer progression-free survival than those who underwent subtotal resection. Using the Kaplan-Meier projection at 10 years, the progression-free survival rate for patients with total tumor resection was 80%, compared with 21% for subtotal resection. All patients showed overall improvement in vision after surgery, with 39% having improved visual fields and 4 patients recovering from other cranial nerve damage.
Two patients required postoperative repair for cerebrospinal fluid leakage; two patients developed infections in the abdominal lipid supply area, one of which was cured by anti-infection and the other required surgical debridement; one patient developed a pseudoaneurysm of the cavernous sinus segment of the carotid artery that presented as delayed epistaxis and was cured by endovascular embolization; and one patient with a macroadenoma developed a postoperative hemorrhage that required secondary hematoma removal. Another 28% of patients presented with postoperative sinusitis in the form of altered olfaction and sinusitis.
Therefore, in the long term, patients with Knosp 0-2 and tumor volumes less than 10 cm3 are more likely to undergo total tumor resection. However, postoperative statistics on the proportion of total tumor resection, new onset hypopituitarism, and episodes of complications did not differ from previous reports.