Post-traumatic spinal hematoma in diffuse idiopathic skeletal hyperostosis (DISH)

OBJECTIVES: To determine the incidence of spinal hematoma and its relation to neurological deficit after trauma in patients with spinal ankylosis from diffuse idiopathic skeletal hyperostosis (DISH). MATERIALS AND METHODS: A retrospective review of 2256 urgent or emergency MRI referrals over a period of 8 years and nine months revealed 70 DISH patients who underwent CT and MRI scans of the spine. Spinal hematoma was the primary outcome. Additional variables were spinal cord impingement, spinal cord injury (SCI), trauma mechanism, fracture type, spinal canal narrowing, treatment type, and Frankel grades during injury, before and after treatment. Two trauma radiologists reviewed MRI scans blinded to initial reports. RESULTS: Of 70 post-traumatic patients (54 men, median age 73, IQR 66–81) with ankylosis of the spine from DISH, 34 (49%) had spinal epidural hematoma (SEH) and 3 (4%) had spinal subdural hematoma, 47 (67%) had spinal cord impingement, and 43 (61%) had SCI. Ground-level fall (69%) was the most common trauma mechanism. A transverse, AO classification type B spine fracture (39%) through the vertebral body was the most common injury type. Spinal canal narrowing (p < .001) correlated and spinal cord impingement (p = .004) associated with Frankel grade before treatment. Of 34 patients with SEH, one, treated conservatively, developed SCI. CONCLUSIONS: SEH is a common complication after low-energy trauma in patients with spinal ankylosis from DISH. SEH causing spinal cord impingement may progress to SCI if not treated by decompression. CLINICAL RELEVANCE STATEMENT: Low-energy trauma may cause unstable spinal fractures in patients with spinal ankylosis caused by DISH. The diagnosis of spinal cord impingement or injury requires MRI, especially for the exclusion of spinal hematoma requiring surgical evacuation. KEY POINTS: • Spinal epidural hematoma is a common complication in post-traumatic patients with spinal ankylosis from DISH. • Most fractures and associated spinal hematomas in patients with spinal ankylosis from DISH result from low-energy trauma. • Spinal hematoma can cause spinal cord impingement, which may lead to SCI if not treated by decompression.