Optical neuronavigation facilitates transcranial surgical access to the equine pituitary gland.

Abstract

Objective: To evaluate the feasibility of an optical neuronavigation-guided transcranial approach to the equine pituitary gland, compare pituitary tissue acquisition using MRI versus CT guidance, and assess an automated tissue resection device versus a standard biopsy needle.

Methods: 13 equine cadaver heads from horses euthanized for reasons unrelated to the study were used. A fiducial array was secured to the frontal bone before imaging; 7 heads underwent CT, and 6 heads underwent MRI. Images were imported into a neuronavigation system for 3-D reconstruction, surgical planning, and registration. Eighteen pituitary biopsy samples were obtained: 7 using a neuronavigation-guided automated morcellation and aspiration device and 11 using a standard biopsy needle. All samples were processed with hematoxylin and eosin staining, and histologic evaluation was performed by a veterinary pathologist blinded to biopsy technique and imaging modality.

Results: Pituitary tissue was confirmed histologically in 7 of 13 heads overall (53.8%): 6 of 6 MRI-guided heads (100%) and 1 of 7 CT-guided heads (14.3%). Both biopsy techniques were applied to each of the 6 MRI-guided heads (paired design); the automated morcellation device yielded pituitary tissue in 4 of 6 heads (66.7%), compared with 2 of 6 heads (33.3%) using the standard biopsy needle.

Conclusions: Optical neuronavigation enabled feasible transcranial access to the equine pituitary gland in cadaveric specimens, with tissue acquisition improved using MRI guidance and automated morcellation.

Clinical relevance: These findings support further investigation of neuronavigation-guided hypophysectomy as a potential treatment for pituitary pars intermedia dysfunction in horses.