Published Online: October 25, 2012. doi:10.1001/jama.2012.12807
Author Contributions: Dr Jakola had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Jakola, Solheim.
Acquisition of data: Jakola, Myrmel, Torp, Lindal.
Analysis and interpretation of data: Jakola, Myrmel, Kloster, Torp, Lindal, Unsgård, Solheim.
Drafting of the manuscript: Jakola.
Critical revision of the manuscript for important intellectual content: Jakola, Myrmel, Kloster, Torp, Lindal, Unsgård, Solheim.
Statistical analysis: Jakola, Solheim.
Obtained funding: Unsgård.
Administrative, technical, or material support: Myrmel, Kloster, Torp, Lindal, Unsgård.
Study supervision: Myrmel, Kloster, Torp, Lindal, Unsgård, Solheim.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Unsgård reports having approximately 0.3% of the stocks in Sonowand, the company making the 3D-ultrasound–based intraoperative imaging system (SonoWand) used in the resections at hospital B. The other authors report no disclosures.
Additional Contributions: We would like to thank Anne-Lise Furnes, administration secretary, Department of Ophthalmology and Neurosurgery, University Hospital of Northern Norway, and Lisa M. Sagberg, research nurse, Department of Neurosurgery, St.Olav's University Hospital for facilitating data collection; statistician Øyvind Salvesen, ScD, associate professor, Norwegian University of Science and Technology, for advice on statistical analyses; and Ole K. Losvik, MD, Department of Neurosurgery, St.Olav's University Hospital, for help with figures. All acknowledged individuals offered assistance without any form of compensation.