Optical neuronavigation facilitates transcranial surgical access to the equine pituitary gland

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.

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.

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.

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

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