Keyhole Revision after Failed Subdural Craniostomy for Chronic Subdural Hematoma

Introduction: An emerging treatment for chronic subdural hematomas is subdural craniostomy using a twist drill port system. While this system has the advantage of being placed in the intensive care setting, and not the operating room, incomplete hematoma evacuation is not uncommon. We detail a simple surgical technique that can be used for persistent or recurrent collections. Materials and Methods: For patients with persistent or recurrent chronic subdural hematomas after bedside subdural craniostomy, the patient is taken to the operating room and a "keyhole" burr hole is used that creates a new burr hole in front of the prior twist drill hole. The subdural space is opened such that there is communication between the larger burr hole and craniostomy hole. The bolt for the twist drill system is then re-inserted so that the tip rests just above the dural opening. The anterior burr hole is capped with a titanium burr hole cover with a sector removed. Results: This method was used in four patients with residual/recurrent subdural hematomas. The mean interval between craniostomy and keyhole revision was 2.8 days (range one to six days). Complications of infection or new acute subdural hematoma occurred in none of the patients. The rate of hematoma recurrence after keyhole revision was 0%. Average operative time for the keyhole procedure was 42.5 minutes (range 28 to 60 min.). Conclusions: The keyhole method for drainage of residual or recurrent chronic subdural hematomas is an option prior to craniotomy that allows for wider opening of the subdural space for hematoma irrigation and removal, while maintaining postoperative extradural