CLINICAL ARTICLE - BRAIN TUMORS Surgical complications after transsphenoidal microscopic and endoscopic surgery for pituitary adenoma: a consecutive series of 506 procedures Helene Halvorsen & Jon Ramm-Pettersen & Roger Josefsen & Pål Rønning & Sissel Reinlie & Torstein Meling & Jon Berg-Johnsen & Jens Bollerslev & Eirik Helseth Received: 24 September 2013 /Accepted: 20 November 2013 /Published online: 17 December 2013 # Springer-Verlag Wien 2013 Abstract Background This single-institution, consecutive series of transsphenoidal procedures included all patients in a defined population of 2.6 million inhabitants who underwent surgery during a specific time period. Objective We sought to determine the surgical complication rate and overall survival rate after transsphenoidal surgery for pituitary adenoma. Methods All transsphenoidal procedures for histologically verified pituitary adenomas performed between September 2002 and February 2011 at our institution were included in this study. The data were obtained from a prospectively col- lected database and from reviewing medical records. No pa- tients were lost to follow-up, and the median follow-up time was 28 months. Results A total of 506 transsphenoidal procedures were per- formed on 446 patients. There were 268 microscopic and 238 endoscopic procedures involving 352 non-functioning and 154 hormone-secreting adenomas. A total of 73 % of the procedures were primary surgeries, and 27 % were repeat surgeries for tumor recurrence. The overall complication rate was 9.1 %. The three most frequent complications were cerebrospinal fluid (CSF) leakage (4.7 %), meningitis (2 %), and visual deterioration (2 %). Multivariate analyses showed that the overall risk for complications increased with older age, surgery for recurrent tumors, and surgery performed by a low-volume surgeon. There was no significant difference in the overall complication rate between the microsurgical and endoscopic techniques. The rate of surgical mortality was 0.6 %, and the overall survival rates at 1 and 5 years were 95 % and 90 %, respectively. The only negative predictor of survival was older age. Conclusions Transsphenoidal surgery for pituitary adenomas has a low complication rate and a low rate of mortality. We did not find a significant difference in the complication rate be- tween endoscopic and microscopic techniques. Keywords Adenoma . Complications . Endoscopy . Microsurgery . Pituitary . Transsphenoidal Introduction Pituitary adenomas constitute approximately 10 % of all pri- mary intracranial tumors [39]. These tumors are classified according to hormonal activity (non-secreting, prolactinoma, or adrenocorticotropic hormone [ACTH]-, growth hormone [GH]- or thyroid stimulating hormone [TSH]-producing) [26]. Surgery is the treatment of choice for most patients, although for prolactinomas the treatment of choice is medical, often with dopamine agonists. Surgery may be an option in prolactinomas if the patient experiences unacceptable side effects from the medication, or if the patient has a strong desire for surgery. The preferred approach is either microscopic or endoscopic transsphenoidal surgery. At our institution, the endoscopic transsphenoidal technique for pituitary adenoma surgery was Helene Halvorsen and Jon Ramm-Pettersen contributed equally to the publication and should be regarded as joint-first authors. H. Halvorsen : J. Berg-Johnsen : J. Bollerslev : E. Helseth Faculty of Medicine, University of Oslo, Oslo, Norway J. Ramm-Pettersen (*) : R. Josefsen : P. Rønning : S. Reinlie : T. Meling : J. Berg-Johnsen : E. Helseth Department of Neurosurgery, Oslo University Hospital, 0027 Oslo, Norway e-mail: jonrammp@gmail.com J. Bollerslev Department of Endocrinology, Oslo University Hospital, Oslo, Norway Acta Neurochir (2014) 156:441–449 DOI 10.1007/s00701-013-1959-7