Ultrasound-assisted microsurgery for pituitary macroadenomas
Ulrich Knappe1, Juergen Rolfes1, Christian Jaspers2, Reinhard Santen3 & Joachim Feldkamp4
Subject: Use of intraoperative ultrasound (iUS) during transshenoidal surgery addresses (a) resection control of macroadenomas and (b) identification of microadenomas, thus avoiding extensive pituitary exploration.
Method: (a) For resection control of 33 pituitary macroadenomas and 2 meningeomas a 13 MHz US probe with a perpendicular 10 mm linear field was introduced into the sella after intrasellar resection to investigate the suprasellar and parasellar compartments. (b) In 20 patients with Cushing`s disease (CD) a 13 MHz probe with straight ahead 5 mm linear field was used for identification of microadenomas before opening of the pituitary capsule.
Results: (a) In macroadenomas, total resection was accomplished in 22 out of 33 cases (67%), in 10 Knosp 0IV adenomas a tailored partial resection was performed. Remission of hypersecretory syndrome was obtained in 9/14 cases (64%). Two infiltrative meningeomas were partially resected. In 18 out of 35 cases further resection after iUS was undertaken (51%). Compared to postoperative MRI, concerning suprasellar tumor remnants iUS was positive in 2/34 cases, false negative in 2, and not applicable in 4 (due to air, one of those false negative). Concerning parasellar tumor remnants iUS was positive in 11/35 cases (2 meningeomas, 9 Knosp 0IV adenomas), false positive in 1/34 (Knosp 0III adenoma), and false negative in one case (Knosp 0II, acromegaly). (b) In CD, 15 out of 19 microadenomas were identified by iUS (79%), including 3/4 cases with negative preoperative MRI. Remission rate of hypercortisolism was 20/20 (100%), other pituitary function were unaltered compared to preoperative state in 19/20 cases (95%). No complications related to iUS occurred.
Conclusion: iUS with high-frequency probes during transsphenoidal surgery improves (a) the extent of resection in infiltrative macroadenomas, (b) the finding rate of microadenomas in CD, and the endocrinological outcome.