The microsurgical technique of transsphenoidal
hypophysectomy performed with the dogs and cats positioned in sternal recumbency enables the treatment of
Cushing's disease, independent of skull type, in a safe and effective manner. In dogs, the short-term survival rate after
hypophysectomy is comparable to that
after treatment with
o,p'-DDD, whereas the recurrence rate in this period is lower. When the surgeon has gone through a learning curve, the results of the 1- to 3-year follow-up interval may be better than those after adrenocorticolysis with
o,p'-DDD. CT enables assessment of localization and size of the pituitary before surgery. In general, dogs with
Cushing's disease and normal-sized pituitaries or moderately enlarged pituitaries (up to 12 mm in diameter) are suitable candidates for transsphenoidal surgery. In dogs with larger
pituitary tumors and
tumor extension rostrally or caudally over the dorsum sellae, transsphenoidal debulking surgery may be only a
palliative treatment. The main complications are postoperative
hypernatremia,
keratoconjunctivitis sicca,
diabetes insipidus, and
secondary hypothyroidism. In cats, special attention should be paid to closure of the soft palate. The neurosurgeon must be familiar with these complications so as to recognize them as early as possible and to treat them immediately and effectively. It is concluded that microsurgical transsphenoidal
hypophysectomy in dogs and cats with
Cushing's disease is an effective method of treatment.