Rate and Time Course of Improvement in Endocrine Function After More Than 1000 Pituitary Operations P ituitary lesions occur quite commonly in the general population, with a prevalence ranging from 2.7% up to as high as 26.7% based on autopsy and magnetic resonance (MR) imaging studies. 1-3 Patients with lesions large enough to cause symptoms present with a variety of concerns, one of which is hypopituitarism, but endocrine deficits may also be found on the initial workup of patients presenting with other indica- tors such as headache or visual deficits. The incidence of hypopituitarism in any 1 axis from sellar lesions has been reported to be 58%, 4 and has been reported to be somewhat higher at 69% to 85% with adenomas, in particular. 5,6 The limited number of studies that have looked at individual axes have suggested that the incidence of deficits vary by axis. 7,8 This hypopituitarism is believed to result from compression and destruction of the pituitary gland by the expanding lesion, while focal necrosis resulting from inhibition of the portal vessels and pituitary stalk may also play a role. 9 The true incidence of endocrine recovery fol- lowing the resection of pituitary lesions is unclear, because many patients receive hormonal replacement therapy indefinitely, limiting the ability to correctly assess this variable. Studies of improved pituitary function after transsphenoidal surgery for nonfunctional adeno- mas have reported considerably variable rates, ranging from 20% of patients 6,10 up to 50% of patients, 11,12 but those studies have failed to look at the improvement rates for individual endocrine axes. Other studies have suggested that improve- ment varies by pathology, being more common after surgery for acromegaly than surgery for nonfunctional adenomas 13 and being uncommon after surgery for Rathke cleft cysts. 14 Studies that have looked at endocrine recovery by specific axis have suggested that recovery varies by axis from 13% to 57% but have been done in smaller cohorts of 35 to 126 patients. 5,7-9 Furthermore, studies focusing on endocrine function recovery after surgery for different tumor types have also involved cohorts of limited size. 15 To address the improvement in endocrine deficits by individual axes after transsphenoidal surgery for the types of pathologies encountered in typical practice in a large cohort, we analyzed preoperative and postoperative endocrine function before and after more than 1000 consecutive pituitary surgeries conducted since we established a center of pituitary expertise 5 years ago. METHODS Study Design, Setting, and Participants We conducted a retrospective review of our 1015 consecutive endonasal pituitary operations on the first 916 patients treated in the 5 years since the California Center for Pituitary Disorders, a dedicated multidis- ciplinary center of pituitary expertise, was established. The 1015 operations consisted of 875 first surgeries performed at our center, 99 reoperations performed at our center on patients whose first surgery was also at our center, and 41 reoperations performed at our center on patients whose first surgery was performed elsewhere. Only endonasal procedures were included, and craniotomies were excluded. Our institutional Committee on Human Research reviewed and approved this study. Preoperative Variables Recorded The parameters collected after review of the medical record included age, sex, lesion size, number of prior pituitary surgeries, lesion type (endocrine- inactive adenoma, endocrine-active adenoma, Rathke cleft cyst, apoplexy, craniopharyngioma, or other), endonasal surgical approach (966 micro- scopic operations vs 49 endoscopic), lesion location (sellar, suprasellar, or sellar with suprasellar exten- sion), and the presence of preoperative hypopituita- rism. Preoperative hypopituitarism was defined based on normal reference ranges from the Univer- sity of California at San Francisco Department of Laboratory Medicine by axis as (1) low free T4 (,10 pmol/L) with normal or low thyroid-stimulating hormone (TSH) (,4.12 mIU/L); (2) amenorrhea with low follicle-stimulating hormone (FSH) (,20 IU/L); (3) testosterone less than 141 ng/dL; (4) cortisol less than 4 mg/dL; and (5) insulin-like growth factor 1 (IGF-1) below 87 mg/L for male and 64 mg/L for female patients. Arman Jahangiri, BS*‡ Jeffrey Wagner, BS*‡ Sung Won Han‡ Mai T. Tran, BS‡ Liane M. Miller, BS‡ MaxwelL W. Tom, BS‡ Lauren R. Ostling, MD§ Sandeep Kunwar, MD‡ Lewis Blevins, MD‡ Manish K. Aghi, MD, PhD‡ ‡Department of Neurosurgery and The California Center for Pituitary Disorders, University of California at San Francisco, San Francisco, California; §Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio *These authors have contributed equally to this work. Correspondence: Manish K. Aghi, MD, PhD, Associate Professor of Neurological Surgery Co-Director, The California Center for Pituitary Disorders (CCPD) and Center for Minimally Invasive Skull Base Surgery (MISB), University of California at San Francisco (UCSF), 505 Parnassus Ave, Room M779, San Francisco, CA 94143-0112. E-mail: AghiM@neurosurg.ucsf.edu Copyright © 2014 by the Congress of Neurological Surgeons. INTEGRA FOUNDATION AWARD INTEGRA FOUNDATION AWARD CLINICAL NEUROSURGERY VOLUME 61 | NUMBER 1 | AUGUST 2014 | 163 Copyright © Congress of Neurological Surgeons. Unauthorized reproduction of this article is prohibited