Practical Use of a Simple Technique, Insertion of Wet Cotton Pledgets into the Tumor Resection Cavity in Transsphenoidal Surgery of Pituitary Tumors, for a Better Comparison between Pre- and Intraoperative High-Field Magnetic Resonance Images

Abstract

Intraoperative high-field magnetic resonance imaging (iMRI) is a useful modality for immediate intraoperative quality control. With iMRI, a surgeon can confirm whether tumor remnants exist during surgery; which makes it possible to add further resection, obtain a higher resection rate, and improve the cure rate. It is sometimes difficult to evaluate the existence of tumor remnants when the tumor resection cavity is collapsed. In this study, we reported a simple technique for comparing pre- and intraoperative MR images. Thirty-five consecutive patients with pituitary adenoma underwent endoscopic endonasal transsphenoidal surgery using iMRI. Twenty-six patients had adenomas with suprasellar extension, and 9 had intrasellar adenomas. Nine adenomas had cavernous sinus invasion. Eight patients had endocrine-active, and 27 endocrine-inactive tumors. The simple technique included wet cotton pledgets inserted into the resection cavity to easily and precisely compare pre- and intraoperative MR images. Furthermore, we evaluated the efficacy of iMRI using our method on determining the extent of tumor resection in this study. The first iMRI scan showed that 12 of 35 patients had some tumor remnants, and 23 patients did not. Eight of these 12 patients with tumor remnants had cavernous sinus invasion. Three cases received further tumor resection after iMRI and had a gross total removal. We presented our initial results after using a simple method in high-field iMRI during endoscopic transnasal transsphenoidal pituitary surgery. This procedure allowed us to obtain valuable information to determine the extent of tumor resection and to precisely visualize the parasellar structures.