Prospective assessment of concomitant lumbar and chronic subdural hematoma: is migration from the intracranial space involved in their manifestation?

Object. Spinal subdural hematomas (SDHs) are rare and some are concomitant with intracranial SDH. Their pathogenesis and etiology remain to be elucidated although their migration from the intracranial space has been suggested. The authors postulated that if migration plays a major role, patients with intracranial SDH may harbor asymptomatic lumbar SDH. The authors performed a prospective study on the incidence of spinal SDH in patients with intracranial SDH to determine whether migration is a key factor in their concomitance. Methods. The authors evaluated lumbar MR images obtained in 168 patients (125 males, 43 females, mean age 75.6 years) with intracranial chronic SDH to identify cases of concomitant lumbar SDH. In all cases, the lumbar MRI studies were performed within the 1st week after surgical irrigation of the intracranial SDH. Results. Of the 168 patients, 2 (1.2%) harbored a concomitant lumbar SDH; both had a history of trauma to both the head and the hip and/or lumbar area. One was an 83-year-old man with prostate cancer and myelodysplastic syndrome who suffered trauma to his head and lumbar area in a fall from his bed. The other was a 70-year-old man who had hit his head and lumbar area in a fall. Neither patient manifested neurological deficits and their hematomas disappeared under observation. None of the patients with concomitant lumbar SDH had sustained head trauma only, indicating that trauma to the hip or lumbar region is significantly related to the concomitance of SDH (p < 0.05). Conclusions. As the incidence of concomitant lumbar and intracranial chronic SDH is rare and both patients in this study had sustained a direct impact to the head and hips, the authors suggest that the major mechanism underlying their concomitant SDH was double trauma. Another possible explanation is hemorrhagic diathesis and low CSF syndrome.