Visualization and Identification of the Pituitary Gland Tissue in Endonasal Pituitary Surgery: Is There a Difference...

Neurosurgical techniques for the treatment of sellar pathologies have been evolving continuously over recent decades. In addition to the innovation of approaches and surgical techniques, this progress yielded to the application of modern operative technologies. The introduction of high-definition (HD) cameras for endoscopic systems has shown good results in endonasal pituitary surgery. The aim of this study was to assess endoscopic HD image quality in comparison with microscopic visualization.

All pituitary surgeries were performed via an endonasal approach in the endoscopic technique. For each comparison, pituitary gland tissue was predefined intraoperatively. A resident was randomly required to identify this tissue either using HD endoscopic or microscopic visualization through the endonasal approach. Subjective image quality was requested with a questionnaire. Furthermore, the illuminance level of the endoscope and microscope was measured in the sellar region in an experimental setup.

Thirty-five procedures were performed and included in this comparison. Of the 35 procedures, 74% of gland tissue cases were identified correctly under endoscopic visualization, whereas it was identified correctly under microscopic visualization in 8% (P < 0.05). There was no significant correlation of experience and intraoperative results in cases of the microscopic (r = -0.15) or endoscopic visualization (r = 0.22). The identification of tissue in the depth of the surgical field via endoscopic HD visualization was thought to be superior to the microscope in 86.8%. Both modalities were assessed equal in 10.4%. Microscopic visualization was rated superior in 2.8% of all cases. There was a significant superiority of endoscopic visualization (P < 0.05). The mean lux level for endoscopic visualization of the sellar region was 221,000. The mean lux level decreased significantly by 66% to 241,000 lx with 350-mm distance and by 60% to 141,000 lx with 450-mm distance because of the positioning of the microscope in front of the head form to visualize the surgical field at the sellar region.

HD endoscopic visualization accounted for significantly more reliable identifications of pituitary gland tissue in comparison with the microscope in the presented setting. The subjective impression of image quality is better with HD endoscopes. The goal of further studies should be to identify if these findings would also result in improved surgical outcome in short-term and long-term follow-up.