gms | German Medical Science

Objective: Feasibility and evaluation of multimodal neuronavigation combined with intraoperative 1,5 Tesla magnetic resonance imaging (MRI) in transspenoidal surgery of complex pituitary adenomas.

Methods: Prospective study of 19 patients with extensive or recurrent pituitary adenomas underwent navigated transsphenoidal adenomectomy followed by intraoperative MRI. When resectable tumor was indentified, resection was continued and imaging repeated until no more resectable tumor could be identified. Navigation for initial tumor resection was updated with intraoperative imaging for targeted resection of remnant tumor. Automatic segmentation of the peritumoral cerebral arteries from magnetic resonace angiography (MRA) was used in the navigation in cases of extrasellar tumor extension.

Results: Complete resection was intended in 13 patients, mass reduction in 6. The first intraoperative MRI confirmed this goal in 9 cases (8 complete resections, 1 mass reduction). Continued resection led to 3 complete and 2 subtotal resections in patients with intended complete resection increasing the proportion of complete tumor resection form 62% to 85%. In the remaining 5 patients, further significant tumor reduction followed imaging. In two patients suspicious findings on intraoperative MRI could not be verified operatively. Except for one cerebrospinal fluid fistula which needed operative repair, no significant adverse events were recorded.

Conclusions: In the selected group of patients with complex pituitary adenomas, the extent of tumor resection was considerably increased. MRI proved a valuable diagnostic tool in identifying tumor remnants intraoperatively. Identification of vascular structures with the navigation based on MRA proved helpful and reliable in the distorted anatomy of patients with large tumors.