A 3-Dimensional Printed Patient-Specific Surgical Guide to Facilitate Transsphenoidal Hypophysectomy in Dogs

Larger surgical caseload is associated with better patient outcome for many complex procedures. We examined the volume-outcome relationship for transsphenoidal pituitary tumor surgery using the Nationwide Inpatient Sample, 1996-2000. Multivariate regression adjusted for patient demographics, acuity measures, medical comorbidities, and endocrine status. A total of 5497 operations were performed at 538 hospitals by 825 surgeons. Outcome measured at hospital discharge was: death (0.6%), discharge to long-term care (0.9%), to short-term rehabilitation (2.1%), or directly home (96.2%). Outcomes were better after surgery at higher-volume hospitals (OR 0.74 for 5-fold-larger caseload, P = 0.007) or by higher-volume surgeons (OR 0.62, P = 0.02). A total of 5.4% of patients were not discharged directly home from lowest-volume-quartile hospitals, compared with 2.6% at highest-volume-quartile hospitals. In-hospital mortality was lower with higher-volume hospitals (P = 0.03) and surgeons (P = 0.09). Mortality rates were 0.9% at lowest-caseload-quartile hospitals and 0.4% at highest-volume-quartile hospitals. Postoperative complications (26.5% of admissions) were less frequent with higher-volume hospitals (P = 0.03) or surgeons (P = 0.005). Length of stay was shorter with high-volume hospitals (P = 0.02) and surgeons (P < 0.001). Hospital charges were lower for high-volume hospitals, but not significantly. This analysis suggests that higher-volume hospitals and surgeons provide superior short-term outcomes after transsphenoidal pituitary tumor surgery with shorter lengths of stay and a trend toward lower charges.

Under the assumption that the impaired inhibitory effect of glucocorticoids on cell division is an important determinant in the progression of corticotrophic adenomas, it is postulated that the magnitude of proliferation and the resistance to glucocorticoids are correlated. To test this hypothesis, 67 dogs with pituitary-dependent hyperadrenocorticism were studied to determine whether a correlation could be demonstrated between the effect of dexamethasone administration on the activity of the pituitary-adrenocortical axis and the size of the pituitary gland as estimated by computed tomography. The volumes of the pituitary glands as calculated from summations of subsequent images of pituitary areas, ranged from 11.8 to 3238.6 mm3. Among the three dimensions, the height of the pituitary was the most sensitive indicator of enlargement. Calculation of the pituitary height/brain area ratio (P/B ratio) allowed correction for the size of the dog. The P/B ratio had the highest discriminatory power in distinguishing enlarged (n = 41) from non-enlarged (n = 26) pituitaries. The effects of dexamethasone (0.1 mg/kg) on the plasma concentrations of cortisol and ACTH and on the urinary corticoid/creatinine (C/C) ratios were expressed as percentage changes from the initial values. For ACTH, cortisol and C/C ratios these figures for resistance to dexamethasone were significantly correlated with the dimensions of the pituitary, particularly the height, volume and P/B ratio. It is concluded that the magnitude of the expansion of pituitary corticotrophic adenomas is dependent upon the loss of restraint by glucocorticoids, i.e. the degree of insensitivity to glucocorticoid feedback.

Background Transsphenoidal hypophysectomy is one of the treatment strategies in the comprehensive management of dogs with pituitary‐dependent hypercortisolism (PDH). Objectives To describe the influence of pituitary size at time of pituitary gland surgery on long‐term outcome. Animals Three‐hundred–and‐six dogs with PDH. Methods Survival and disease‐free fractions were analyzed and related to pituitary size; dogs with and without recurrence were compared. Results Four weeks after surgery, 91% of dogs were alive and remission was confirmed in 92% of these dogs. The median survival time was 781 days, median disease‐free interval was 951 days. Over time, 27% of dogs developed recurrence of hypercortisolism after a median period of 555 days. Dogs with recurrence had significantly higher pituitary height/brain area (P/B) ratio and pre‐operative basal urinary corticoid‐to‐creatinine ratio (UCCR) than dogs without recurrence. Survival time and disease‐free interval of dogs with enlarged pituitary glands was significantly shorter than that of dogs with a non‐enlarged pituitary gland. Pituitary size at the time of surgery significantly increased over the 20‐year period. Although larger tumors have a less favorable prognosis, outcome in larger tumors improved over time. Conclusions and Clinical Importance Transsphenoidal hypophysectomy is an effective treatment for PDH in dogs, with an acceptable long‐term outcome. Survival time and disease‐free fractions are correlated negatively with pituitary gland size, making the P/B ratio an important pre‐operative prognosticator. However, with increasing experience, and for large tumors, pituitary gland surgery remains an option to control the pituitary mass and hypercortisolism.