spinal subdural hematomas ( sdh ) are rare and are known to lead to cauda equina and/or spinal cord compression . in the literature , previous studies have linked spinal sdh to hemorrhagic disorders , trauma , spinal surgery , lumbar puncture or spinal anesthesia , spinal vascular malformations and spinal tumors1,3,5,16 ) .
although the incidence of spinal sdh is quite low , it can occur in the absence of any of the known risk factors .
equally as rare , spinal sdh has been reported to arise as a complication in patients with intracranial sdh2,6,8,10 - 14,16 ) .
, we report a case of intracranial sdh with subsequent spinal sdh , and propose a potential mechanism for the cause of concomitant hematomas .
a 47-year - old female patient was referred to our hospital due to sudden onset of headache ( visual analog scale ; vas 8) and backaches ( vas 6 ) following a slip and fall two weeks prior to admission , resulting in periorbital swelling , bruising and a headache .
the patient showed no sensory and motor deficits in lower limbs and there were neither bladder nor bowel dysfunction .
she was alert and well oriented , and her spine was aligned normally in the coronal plane with mild loss of lumbar lordosis .
lumbar spine movements in the sagittal plane were restricted by pain . upon straight leg - raise testing , the patient 's leg was able to be raised 60 while lying down , with no neurological deficits noted in the limbs .
her coagulation profiles including platelet count , prothrombin time , and activated partial thromboplastin time were all within the normal ranges .
cranial imaging studies revealed a small amount of acute sdh along the tentorium ( fig .
1 ) . magnetic resonance imaging of the patient 's lumbosacral spine revealed spinal sdh at the anterior portion of the caudal thecal sac at the levels of l5-s2 with marked neural compression ( fig .
the remaining intracranial structures and cervicothoracic spine were normal . based on radiologic findings , traumatic intracranial sdh at the tentorium with subsequent spinal sdh
seven - day course of conservative management was uneventful , and the patient experienced no neurological deficits , without notable event .
her complaints of headache and back pain were nearly resolved , and the patient returned to normal daily activities . at one - year follow - up ,
the patient was free of leg pain , but complained of a sustained mild headache .
sdh following cranial subdural hematoma is extremely rare , with only a few cases having been reported previously2,6,8,10 - 14,16 ) .
the pathogenesis of traumatic sdh following intracranial subdural hematoma is difficult to explain in the absence of any violation of the dural layer . unlike the intracranial subdural space ,
spinal hematomas may migrate from a cranial lesion , a view that has been supported by many authors15 ) .
lecouvet et al.11 ) explained that the propagation of blood from cranial to spinal subdural space is possible due to the presence of anatomic continuity between them .
the authors of several reports also have described the spontaneous resolution of acute intracranial subdural hematoma . when this occurs , redistribution of subdural blood is often observed with layering along dependent areas such as the tentorium . in view of the presented patient 's history of a dramatic resolution of an acute intracranial subdural hematoma with redistribution of blood ,
we hypothesize that the development of sdh might have been related to a progressive migration of subdural blood to the most dependent areas of the lumbosacral region under the influence of gravity . in other words ,
the hematoma may have attained a liquefied form and migrated through the subdural space14,16 ) .
this theory is supported by previous electron microscopic observation of an anatomical continuity between the intracranial and spinal subdural space7 ) .
the continuity between the intracranial subdural space and that of the spine has thusly been proven . in a previous study ,
haines et al.4 ) examined the dura - arachnoid junction at an electron microscopic level and demonstrated that although the external dural layer is strong , the inner dural or meningeal dural layer is structurally weak and vulnerable to injury . under normal conditions , there is no space at the dura - arachnoid junction .
shrunken brain due to trauma may open this " potential space " and allow fluid to collect in this space .
if fluid collection continues , it may be gravitationally pulled downward along the potential space of the spine9 ) .
this process may also damage the small anastomosing network of extremely delicate spinal dural vessels , so that a symptomatic hematoma may then be formed .
the spinal subdural space comprises a small anastomosing network of extremely delicate vessels , which are directed longitudinally along the lateral margins of the dura mater . however , their extremely small sizes hinder them being a source of hemorrhage .
it is generally agreed that prompt laminectomy with evacuation of the hematoma should be performed before irreversible damage to the spinal cord occurs . however , including our patient , ten of the twenty cases reported in the literature demonstrated a benign course along with spontaneous resolution of thoracic or lumbar subdural hematoma with conservative treatment .
accordingly , an operation should only be considered for cases involving progressive neurologic deficits or persistent symptoms .
although the exact pathogenetic mechanism and prevalence is not certain , we hypothesize that the occurrence of sdhs might be related to a progressive migration of subdural blood to the most dependent areas of the lumbosacral region under the influence of gravity . in other words , the hematoma may attain a liquefied form and migrate through the subdural space .
accordingly , in patients with intracranial subdural hematoma complaining of lower back pain and weakness in both legs , lumbosacral mr examination should be performed to exclude the coexistence of sdh .
 coexistence of cranial and spinal subdural hematomas is rare and only a few cases have been reported in the literature . 
 herein , we report a case of cranial and spinal subdural hematomas after previous head trauma . as the pathogenesis of simultaneous intracranial and spinal subdural hematoma yet remains unclear , we developed an alternative theory to those proposed in the literature for their coexistence , the migration of blood through the subdural space . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION