Canine Hypophysectomy Using a Ventral Paramedian Approach
To evaluate the degree of pituitary exposure, completeness of hypophysectomy, and perioperative morbidity associated with an alternative paramedian surgical approach and excisional technique for the canine pituitary gland. Study Design
Experimental imaging, surgical, and endocrinologic study. Animal Population
Nine healthy, purpose-bred Beagle dogs. Methods
Surgical landmarks for the pituitary were determined by computed tomography (CT), and then using a ventral paramedian approach medial to the rami of the mandible, the pituitary was exposed and removed en bloc by manipulation and ultrasonic aspiration. Efficacy of the procedure was evaluated using endocrinologic and pathologic observation. Results
CT images allowed the precise location of surgical landmarks for hypophysectomy. Statistically significant decreases in secretion of all measured pituitary hormones except adrenocorticotropic hormone (ACTH) occurred after hypophysectomy. Despite the absence of gross evidence of residual pituitary tissue, immunohistochemical staining revealed residual pituitary cells in the sella turcica of most dogs. Conclusion
CT imaging and a paramedian approach facilitated surgical access to the pituitary gland by a transoral technique; however, use of an ultrasonic aspirator removed all visible pituitary glands but left cellular remnants capable of ACTH secretion in the sella turcica. Clinical Relevance
Although this technique did not result in complete hypophysectomy, clinical use in dogs with pituitary-dependent hyperadrenocorticism is warranted because the goal is not complete hypophysectomy but removal of a pituitary tumor.
Document Type: Research Article
Affiliations: From the Departments of Clinical Sciences and Anatomy, Physiology and Pharmacology College of Veterinary Medicine, Auburn University, AL.
Publication date: May 1, 2005