Title {1}	Postoperative drainage for 6, 12, or 24 h after burr-hole evacuation of chronic subdural hematoma in symptomatic patients (DRAIN-TIME 2): study protocol for a nationwide randomized controlled trial
Trial registration {2a and 2b}	ISRCTN15186366. 10.1186/ISRCTN15186366. Registered in December 2020
Protocol version {3}	7th of September 2021, version 2
Funding {4}	This study is funded by the four neurosurgical departments in Denmark. No external funding is involved.
Author details {5a}	1Odense University Hospital Dept. of Neurosurgery J.B. Winsløwsvej 4, DK-5000 Odense Denmark E-mail: mads.groenhoej@rsyd.dk 2Rigshospitalet Dept. of Neurosurgery Blegdamsvej 9, DK-2100 Copenhagen Denmark E-mail: tjens07@gmail.com 3Aarhus University HospitalDept. of Neurosurgery Palle Juul-Jensens Boulevard 99, DK-8200 Aarhus Denmark E-mail: ansind@rm.dk 4Aalborg University Hospital Dept. of Neurosurgery Hobrovej 18-22, DK-9000 Aalborg Denmark E-mail: r.miscov@rn.dk 5Aalborg University Hospital Dept. of Neurosurgery Hobrovej 18-22, DK-9000 Aalborg Denmark E-mail: tohu@rn.dk 6Department of Mathematics and Computer Science University of Southern Denmark Campusvej 55, DK-5000 Odense Denmark E-mail: bdebrabant@sdu.dk 7Epidemiology, Biostatistics and Biodemography Department of Public Health University of Southern Denmark J.B. Winsløwsvej 9b, DK-5000 Odense Denmark E-mail: bdebrabant@sdu.dk 8Aalborg University Hospital Dept. of Neurosurgery Hobrovej 18-22, DK-9000 Aalborg Denmark E-mail: c.bjarkam@rn.dk 9Aarhus University HospitalDept. of Neurosurgery Palle Juul-Jensens Boulevard 99, DK-8200 Aarhus Denmark E-mail: bo.bergholt@rm.dk 10Rigshospitalet Dept. of Neurosurgery Blegdamsvej 9, DK-2100 Copenhagen Denmark E-mail: kaare.fugleholm.buch@regionh.dk 11Odense University Hospital Dept. of Neurosurgery J.B. Winsløwsvej 4, DK-5000 Odense Denmark E-mail: frantz.r.poulsen@rsyd.dk 12Department of Clinical Research and BRIDGE—Brain Research Inter-Disciplinary Guided Excellence, University of Southern Denmark, DK-5000 Odense, Denmark
Name and contact information for the trial sponsor {5b}	Not applicable, no trial sponsor
Role of sponsor {5c}	Not applicable, no study sponsor or funders