gms | German Medical Science

Objective: Intraoperative magnetic resonance imaging (ioMRI) offers an update of neuronavigation and intraoperative resection control during surgery. The high field technique additionally provides information about vascular structures at risk and precise information about extrasellar residual tumor readily available during the procedure. The imaging however, extends time of surgery. We therefore conducted a retrospective study to compare postoperative outcome and residual tumor in conventional transsphenoidal surgery (TS) with and without ioMRI.

Method: A total of 143 patients were assessed. A cohort of 67 patients who had surgery before introduction of ioMRI was compared with a cohort of 76 patients who had surgery since ioMRI became routine in TS. Residual tumor, complications, hormonal dependency, biochemical remission rates and improvement of vision were assessed at 6 months follow-up. A volumetric evaluation of residual tumor was performed in case of parasellar tumor extension.

Results: Majority of patients suffered from non functioning pituitary adenomas in both groups. The ioMRI group enclosed a higher proportion of parasellar and recurrent tumors. At six months follow-up assessment, vision improved in 32% of ioMRI-patients versus 23% in the conventional group. One postoperative intrasellar bleeding was found in conventional group. Minor complications were found in 10 % of ioMRI group and in 4.5% of conventional group. No differences between groups were found for hormonal dependency and biochemical remission rates. Time of surgery was significantly lower in the conventional treatment group. Overall, 37% in ioMRI group and 41% in conventional surgery group harbored a residual tumor after surgery. An intended total resection was achieved significantly more often in ioMRI group (91%) than in conventional group (73%). Cases with a planned subtotal resection showed higher mean volumes of residual tumor in conventional group. There was a significant lower incidence of intrasellar tumor remnants in ioMRI group than in conventional group.

Conclusions: Rate of hypopituitarism was not influenced by ioMRI. Surgical time and was significantly higher with adjunct of ioMRI. Rate of minor complications was higher in ioMRI group, even though no significance was found. Residual tumor volume in cases of planed subtotal resection was lower with ioMRI. Rate of intrasellar tumor remnants was significantly higher without use of ioMRI. Rate of a total adenomectomy was significantly higher with ioMRI.