A watertight dural closure is difficult to achieve after transoral-transclival operation for ventral intradural lesions at the craniocervical junction. These procedures have a high morbidity and mortality from cerebrospinal fluid (CSF) fistula, meningitis, and abscess. We used a canine model to test three different techniques of dural closure after transoral intradural operation: primary suture closure, laser patch weld, and fibrin glue patch closures. The primary suture closure technique was inadequate. All eight leaked CSF at the time of operation, and five had radiographic leaks and were incompetent at autopsy. All seven of the laser closures leaked CSF at operation, yet only one was incompetent at autopsy. The fibrin glue technique was superior and provided a solid seal at operation, even with repeated Valsalva maneuvers to 40 mm Hg. The immediate and persistent seal at operation is clinically significant because it may prevent CSF leak, meningitis, and abscess formation in human patients after transoral surgery. Fibrin glue is excellent for repairing complex dural defects and merits evaluation in clinical trials.