Transorbital approach to the porcine pituitary

A transorbital approach to the pituitary gland is described in domestic swine weighing between 40 and 70 kg. A transpalpebral eye exenteration is performed and the optic canal is enlarged caudally, using a bone drill. An operating microscope is used to improve visualization of the surgical site as the pituitary stalk and anterior pituitary are exposed to the level of the optic chiasm. This approach exposes the pituitary sufficiently to perform either a hypophyseal stalk transection or a hypophysectomy or to implant cannulas for hypothalamic-hypophyseal portal blood sampling. This technique has been performed in more than 50 pigs without major complications. Postoperative recovery has been rapid and uneventful. The transorbital approach is a significant refinement of the frontal craniotomy and cerebral elevation technique previously described in the pig, and results in shortened surgery time, minimal brain manipulation, and greatly decreased morbidity.