spinal subarachnoid hemorrhage ( sah ) is a rare event and accounts for less than 1% of all cases reported in the literatures1 ) . the most common etiology of spinal sah is bleeding from a spinal cord arteriovenous malformation ( avm ) and arteriovenous fistula ( avf ) , which can lead to formation of an aneurysm in a feeding artery . also , spinal sah is usually associated with hemorrhage from intraspinal neoplasms ( e.g. , neurinoma , ependymoma , and hemangioblastoma ) , polyarteritis nodosa , syphilis , aortic coarctation , infection , connective tissue disease , and trauma3 ) . solitary aneurysms of spinal arteries lacking associated above mentioned entities are extremely rare8 ) . we present a case of a ruptured dissecting aneurysm of the radiculomedullary branch of the adamkiewicz artery associated with sah . a 45-year - old female patient was referred to our emergency department with a sudden burst headache and severe back pain , followed by nausea . on admission , she was alert , oriented , and cooperative . on neurological examination , she had moderate neck stiffness with mild lower limb motor weakness of iv / v . no abnormal findings were observed on brain computed tomography . however , brain magnetic resonance imaging ( mri ) revealed thin sah in right parietal lobe cortex . whole spine mri showed spinal sah from t5 to sacrum with a small intradural extramedullary signal void lesion at the t12 level ( fig . 1 ) . spinal angiography revealed a small pearl and string - like aneurysm of a radiculomedullary branch of the left segmental artery ( adamkiewicz artery ) originating on the left side at the l1 level ( fig . the findings and treatment options were discussed with the patient 's family , and we refrained from performing operative clipping or endovascular coiling of the aneurysm because of the high risk of occlusion of the anterior spinal artery during the procedure . over time , the patient improved gradually and was discharged without new neurological deficits . however , one month after onset , she complained aggravation of back pain and radiating pain of both legs , and follow - up lumbar mri showed decreased hematoma and developed arachnoiditis of cauda equina ( fig . 3 ) . two months after the initial onset , her symptoms improved completely , and follow - up lumbar mri showed resolution of sah with septated intradural fluid collection and remaining signal void lesion at the t12 level . the patient 's subsequent clinical follow - up of five months was uneventful ( fig . solitary aneurysms of spinal arteries are rare , and especially , solitary aneurysms of adamkiewicz artery are extremely rare . only 7 cases of ruptured solitary aneurysm of adamkiewicz artery , including the present case , have been reported ( table 1)1,2,5,8,10 ) . several pathogenesis of solitary spinal artery aneurysms , including inflammatory processes , arterial dissections , and intimal defects , have been proposed as potential etiologies for these rare isolated lesions4 - 6,9 ) . although , the exact etiology of this aneurysm remains speculative , in the present case , according to morphology of fusiform aneurysm , we hypothesized that dissection , as primary event , resulted in the formation of a pseudoaneurysm with subsequent hemorrhage . spinal aneurysms differ from intracranial aneurysms in several ways . in most cases , intracranial aneurysms that rupture are saccular or berry aneurysms occurring at bifurcation points along the intracranial arterial tree . otherwise , most spinal artery aneurysms are small with diameter of <3 mm , and although both saccular and fusiform aneurysms have been identified , the latter are more frequent . in addition , solitary spinal aneurysms tend to occur along the intradural portion of the radicular artery as it courses to their spinal cord rather than branch point . the majority of spinal aneurysms involve either the artery of admakiewicz or the thoracolumbar radicular branches . the anterior spinal artery is often involved , but aneurysms can involve the posterior spinal artery or lateral spinal artery3 ) . the caliber of the spinal arteries is much smaller than that of intracranial arteries , and they tend to be less affected by atherosclerosis8 ) . partial thrombosis or acute dissection of spinal aneurysms is a common surgical finding and probably accounts for their symptoms . the specific symptoms of a ruptured spinal aneurysm seem to correlate well with the level and severity of hemorrhage ; however , the abrupt onset of pain appears universal3 ) . lesions involving the upper cervical spine usually become symptomatic with intracranial sah or quadriparesis4,9 ) . lesions in the thoracolumbar spine can cause headache , nuchal pain , abdominal pain , lower back pain , sensory disturbance , or acute paraparesis6 ) . also , an unruptured aneurysm in the cervical or thoracic spine manifested with compressive myelopathy3 ) . our case is unusual because of the aneurysm location at t12 and the presentation with sah of parietal lobe causing headache and nausea . although spinal aneurysms are a rare cause of intracranial sah , the diagnosis should be considered when no other source of hemorrhage can be identified or when the sah is limited to the spine . furthermore , when patient complains increasing intracranial pressure sign , meningeal irritation sign , and severe trunk pain simultaneously , spinal vascular disease should be considered . for focal lesions , aneurysms should be included in the differential diagnosis , and angiography should be performed . the differential diagnosis should be directed toward the exclusion of different types of spinal vascular disease ( e.g. , avm or avf ) , vasculitis , and noninflammatory vasculopathies before the performing of surgical or endovascular treatment . spinal aneurysms associated with hemodynamic flow states , such as avm or avf , have been successfully treated using endovascular and surgical techniques . these types of aneurysms are more amenable to treatment because they are typically associated with robust collateral flow to the anterior spinal artery7 ) . however , no standard therapy has been established because of the infrequence of sah from a ruptured isolated spinal artery aneurysm . therefore , the controversy on clipping and trapping or coil embolization or conservative treatment is not resolved . surgical treatment of spinal artery aneurysms may be required , depending on whether or not blood flow is present distal to the lesion , and offers the potential advantage of preservation of the nearby perforators , as well as the possibility of vascular bypass . the mass effect of aneurysms or surrounding blood clots may be the indication of surgical treatment . the anterior spinal artery and the artery of adamkiewicz must be preserved , and the aneurysm can be resected . however , in general , because these aneurysms are fusiform and lack a surgical neck , direct clipping is usually not possible . if there is no evidence of flow distal to the aneurysm , the parent vessel can be sacrificed and the aneurysm can be resected without risk . if there is evidence of distal blood flow at surgery and the aneurysm can not be directly clipped , the lesion can be wrapped and clip reinforced to minimize the risks of recurrence10 ) . when the bulk of the aneurysm makes wrapping impossible , direct microvascular reconstruction can be attempted . the position of the aneurysm with respect to the spinal cord - anterior , lateral , or posterior - is a key determinant of the surgical approach . if the aneurysm is located anterolateral or posterior to the spinal cord , a traditional posterior laminotomy can be used . sectioning the dentate ligament improves exposure from a posterior approach and also can be used to retract the spinal cord . if the aneurysm is located in the midline , anterior to the spinal cord in the lower thoracic region , anterior approach can be used . during the operation , somatosensory and motor evoked potentials must be recorded . endovascular treatment may be an appropriate choice , especially if surgery is difficult considering the location of the lesion or the condition of the patient . the use of the small - size catheter may prevent undirected local occlusion and spasm of spinal artery . endovascular procedures can be used to occlude only aneurysm or occlude the parent vessel when there is little or no flow distal to the lesion7 ) . alternative to surgical or endovascular treatment , limited to isolated spinal dissecting aneurysm with the small size of artery and the presence of distal flow , spontaneous healing of the dissection and obliteration of the aneurysm may be the possible approach . in 2005 , berlis et al.1 ) proposed a wait - and - see strategy for these aneurysms . our patient had classical fusiform aneurysm with no surgical neck and with blood flow distal to the lesion . surgical clipping of aneurysm or trapping of parent artery carries high risk of injury of adamkiewicz artery during the procedure . also , endovascular treatment was not amenable due to the inaccessibility of the anterior spinal artery and risk of occlusion of adamkiewicz artery during intervention . as a result , in our case , conservative therapy may be preferred because of the small size of the artery and the presence of distal flow . if surgical intervention is delayed for any reason or if emergency surgery is not needed , repeat angiography should be considered before initiation of any delayed intervention , because spontaneous regression is likely . we have described a patient who suffered severe headache and back pain following spinal sah due to rupture of dissecting aneurysm of radiculomedullary branch of the adamkiewicz artery . in any patient with acute severe back pain with sah , spinal vascular disease should be considered . also , subsequent spontaneous resolution of spinal sah indicates that the wait - and - see strategy may provide adequate treatment option .
spinal subarachnoid hemorrhage ( sah ) due to solitary spinal aneurysm is extremely rare . 
 a 45-year - old female patient visited the emergency department with severe headache and back pain . 
 imaging studies showed cerebral sah in parietal lobe and spinal sah in thoracolumbar level . 
 spinal angiography revealed a small pearl and string - like aneurysm of the adamkiewicz artery at the t12 level . 
 one month after onset , her back pain aggravated , and follow - up imaging study showed arachnoiditis . 
 two months after onset , her symptoms improved , and follow - up imaging study showed resolution of sah . the present case of spinal sah due to rupture of dissecting aneurysm of the adamkiewicz artery underwent subsequent spontaneous resolution , indicating that the wait - and - see strategy may provide adequate treatment option .