title: Results of transsphenoidal hypophysectomy in 52 dogs with pituitary-dependent hyperadrenocorticism.
abstract: OBJECTIVE
  To evaluate microsurgical transsphenoidal hypophysectomy in dogs with pituitary-dependent hyperadrenocorticism (PDH).
  
  
  METHODS
  Prospective study to evaluate the results (survival and disease-free interval, remission, recurrence) and complications of microsurgical transsphenoidal hypophysectomy by clinical follow-up, computed tomography (CT), and urinary corticoid-to-creatinine (C/C) ratios in dogs with PDH. The effect of surgical experience was investigated by comparing results of hypophysectomy cases 1 through 26 and 27 through 52.
  
  
  METHODS
  52 dogs with PDH.
  
  
  RESULTS
  Preoperative CT enabled accurate assessment of pituitary size (24 nonenlarged and 28 enlarged) and localization relative to intraoperative anatomic landmarks. Treatment failures included procedure-related mortalities (five dogs) and incomplete hypophysectomies (four dogs). The 1-year estimated survival rate was 84% (95% confidence interval [CI], 71% to 92%). The 2-year estimated survival rate was 80% (95% CI, 65% to 90%). In 43 dogs, the hyperadrenocorticism went into remission. Hyperadrenocorticism recurred in five dogs. The 1-year estimated relapse-free fraction was 92% (95% CI, 76% to 97%). The main complications were transient, mild, postoperative hypernatremia; transient reduction or cessation of tear production (25 eyes in 18 dogs); permanent (five dogs) or prolonged (nine dogs) diabetes insipidus; and secondary hypothyroidism. Normal tear production had resumed in all but one case after a median period of 10 weeks. In the second case series (27 through 52), the hospitalization period was shorter, the number of dry eyes fewer, the survival fraction greater, and the postoperative mortality lower than in the first series. In 15 dogs in which remission was obtained, postoperative CT images suggested the presence of small pituitary remnants; in 1 of these, hyperadrenocorticism recurred. In 46 dogs, the histological diagnosis was pituitary adenoma.
  
  
  CONCLUSIONS
  Microsurgical transsphenoidal hypophysectomy in dogs with PDH is an effective method of treatment in specialized veterinary institutions having access to advanced pituitary imaging techniques. Postoperative CT findings do not correlate well with remission or subsequent recurrence of hyperadrenocorticism.
  
  
  CONCLUSIONS
  The neurosurgeon performing hypophysectomies must master a learning curve and must be familiar with the most frequent complications of the operation to recognize them as early as possible and to treat them immediately and effectively. Urinary C/C ratios are sensitive indicators for the assessment of remission and recurrence of hyperadrenocorticism.
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
authors.forename: B P
authors.initials: BP
authors.lastname: Meij
authors.forename: G
authors.initials: G
authors.lastname: Voorhout
authors.forename: T S
authors.initials: TS
authors.lastname: van den Ingh
authors.forename: H A
authors.initials: HA
authors.lastname: Hazewinkel
authors.forename: E
authors.initials: E
authors.lastname: Teske
authors.forename: A
authors.initials: A
authors.lastname: Rijnberk
mesh_terms: D000308:Adrenocortical Hyperfunction / Q000209:etiology / Q000601:surgery / Q000662:veterinary*; D000818:Animals; D018572:Disease-Free Survival; D004283:Dog Diseases / Q000209:etiology / Q000601:surgery*; D004285:Dogs; D005260:Female; D005500:Follow-Up Studies; D006965:Hyperplasia / Q000662:veterinary; D007016:Hypophysectomy / Q000379:methods / Q000662:veterinary*; D008297:Male; D008866:Microsurgery / Q000662:veterinary; D010900:Pituitary Diseases / Q000150:complications* / Q000000981:diagnostic imaging; D010902:Pituitary Gland / Q000000981:diagnostic imaging / Q000473:pathology; D011183:Postoperative Complications / Q000097:blood / Q000401:mortality / Q000662:veterinary; D011188:Potassium / Q000097:blood; D011446:Prospective Studies; D012008:Recurrence; D012074:Remission Induction; D012964:Sodium / Q000097:blood; D013100:Sphenoid Bone / Q000000981:diagnostic imaging / Q000601:surgery; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000662:veterinary
chemical_list: D012964:Sodium; D011188:Potassium