Spinal subdural hematoma and ankylosing spondylitis: case report and review of literature

Spinal subdural hematomas are rare, disabling hemorrhages. Ankylosing spondylitis (AS) is a relatively common inflammatory condition of the spine that can progress to a fragile, unstable fusion vulnerable to fracture. While spinal epidural hematomas have been described, subdural hematomas to date have not been reported in AS. In this report, we describe the unique case of a patient on warfarin with AS who developed a spinal subdural hematoma and fracture in the absence of trauma. We then discuss the pathogenesis, presentation, prognosis, and management strategies for this unique diagnosis. A 60-year-old man with recent AS diagnosis and atrial fibrillation on warfarin presented with 96 h of low back pain and 24 h of leg weakness and urinary retention. CT imaging revealed a bamboo spine and fracture of the posterior elements at L4, while MR revealed a hematoma with thecal sac compression. The warfarin was reversed and the patient taken to the operating room; on laminectomy, however, no hematoma was encountered. The patient then underwent intraoperative ultrasound, durotomy, and evacuation of a thick subdural hematoma, followed by posterior fusion. This case represents the first report of an AS patient who developed a subdural hematoma requiring evacuation. Although rare, the clinician should maintain a broad differential and be familiar with this unique pathology, particularly in high-risk patients, such as those with suspected fractures or on warfarin. In patients with back pain and myelopathic symptoms, rapid diagnosis followed by prompt evacuation allows for the best opportunity for neurologic recovery.