Acute subdural hematoma following halo pin tightening in a patient with bilateral vertebral artery dissection.

We report the first case of acute subdural hematoma (SDH) developing after tightening the halo of an osteoporotic 61-year-old woman on warfarin therapy for bilateral traumatic vertebral artery dissection. We discuss literature relevant to this case with an emphasis on identifying warning signs, including recurrent pin loosening, especially in patients with compromised bone structure and high risk of bleeding. Our 61-year-old patient presented to neurosurgery clinic for a 2-month follow-up of a type-III odontoid fracture sustained in a motor vehicle accident. The patient had repeatedly loosened halo pins, and shortly after the pins were tightened, the patient had a syncopal event and struck her head. An emergent computed tomography scan revealed acute SDH requiring emergent craniotomy and evacuation. SDH following pin penetration in a patient with bilateral vertebral artery dissection, osteoporosis, and anticoagulation has not been reported as a complication of the use of the halo vest for stabilization of the cervical spine. The risk of this serious complication can be minimized by giving special consideration to patients with comorbidities and by repositioning problematic pins. This case demonstrates the importance of special attention to bone strength, bleeding risk, and recurrent minor complaints with use of the halo vest.