Visualization of the normal pituitary gland during the endoscopic endonasal removal of pituitary adenoma by narrow band imaging.

Abstract

Narrow band imaging (NBI) is an endoscopic technology that enhances the visualization of the superficial and submucosal vasculature. The aim of the present study was to evaluate the feasibility of NBI in visualizing the normal pituitary gland during the endoscopic endonasal removal of pituitary adenoma. A total of 25 patients with pituitary adenoma underwent endoscopic endonasal transsphenoidal surgery using a rigid endoscope with conventional imaging. The NBI of the surgical field was conducted under air and/or continuous irrigation of artificial cerebrospinal fluid using a flexible videoscope before and/or after the gross removal of the tumor. The capillaries of the normal pituitary gland had a characteristic appearance that could be confirmed in 16 cases. In contrast, the adenomas exhibited no characteristic vascular enhancement under NBI. The reasons why NBI failed to visualize the pituitary gland included the presence of a blood clot or a certain amount of tumor obscuring the normal pituitary gland and difficulty in steering the videoscope within the sella to approach the assumed site of the residual pituitary gland. NBI observation during the endoscopic endonasal removal of pituitary adenoma may be useful for visualizing the normal pituitary gland after the gross removal of the tumor. The absence of a typical vascular pattern suggests the presence of a residual tumor, which may justify further exploration in cases where gross total removal is considered necessary.