Martin Bettag, Trier, Germany
This is a single-institution retrospective study on the results of transsphenoidal surgery in GH-producing pituitary adenomas causing acromegaly. Patients were either operated on with the aid of a microscope (n = 23) or an endoscope (n = 42), and the results were compared. Basically, the results showed no significant difference in the rate of gross total tumor resection and also in the rate of biochemical remission. In the subgroup of parasellar extension into the cavernous sinus, there was a tendency of higher gross total resection rate in the endoscopic group. In view of complications, in the microscopic group, there was a significant higher rate of temporary as well as permanent diabetes insipidus.
The main disadvantage of this study is the fact that it is non-randomized and only two surgeons were involved, each one of them performed only one technique. The rate of temporary (34.7 %) and permanent (17.3 %) diabetes insipidus in the microscopic group is much higher than otherwise reported in the literature. So, this may be rather a surgeon-related than a technique-related complication. Also, the number of patients is fairly low. Gross total tumor resection is an important goal, but much more important is the rate of biochemical remission. In the endoscopic group, the overall remission rate was 45.2 %. More than a half of the patients in the endoscopic group could not be cured surgically. We have to accept that regardless of the mode of resection, biological factors do influence the rate of surgical cure rate in acromegaly. Patients with high preoperative GH levels and radiological signs of tumor invasion are less likely to achieve remission by surgery alone and most of them need an adjuvant multimodality treatment with medication and/or various forms of radiation therapy (1).
1. Robert M. Starke, Daniel M. S. Raper, Spencer C. Payne, Mary L. Vance, Edward H. Oldfield, John A. JaneJr. (2013) Endoscopic vs Microsurgical Transsphenoidal Surgery for Acromegaly: Outcomes in a Concurrent Series of Patients Using Modern Criteria For Remission. The Journal of Clinical Endocrinology & Metabolism 98:8, 3190–3198
Makoto Nakamura, Hannover, Germany
The authors present a retrospective study of 65 acromegalic patients who underwent transsphenoidal surgery using endoscopic or microscopic techniques. Patients were operated between 2000 and 2013 and were assigned to two senior pituitary surgeons. One surgeon routinely used the microscopic approach and the other surgeon the endoscopic approach. Two different operative techniques were provided according to the existing referral patterns. The endoscopic approach was performed in 42 patients, while the microscopic approach was performed in 23 patients. Despite of the retrospective nature of their study with its well-known limitations concerning interpretation of the results, interesting data are provided. The authors showed that there was no significant difference in the rates of biochemical remission between the endoscopic and microscopic techniques. However, gross total resection was more often achieved in tumors with cavernous sinus involvement using the endoscopic technique. Suprasellar or infrasellar extension of the tumor did not have any influence on GTR rates in both groups. When radical tumor removal (including the intracavernous portion of the tumor) is intended, better lateral visualization could be obtained with the endoscope. It needs to be pointed out that the rate of cavernous sinus invasion in this series was quite high with 49 %. Interestingly, concerning postoperative complications, DI was significantly higher in the microscopic group. It may be due to better visualization through the endoscope but on the other hand, new postoperative pituitary deficit of the anterior lobe was potentially higher in the endoscopic group (although not statistically significant), which is rather in contrast to the before mentioned. This retrospective study showed that the main goal of hormonal remission can be achieved with comparable success, either using the microscopic or endoscopic method, provided that surgery is performed by experienced pituitary surgeons. It will be of continuing interest, whether further implementation of HD and 3D techniques will have an impact on surgical outcome of these patients.