hypervascular bone metastases and vascular spinal tumors can cause high volume blood loss during open surgery.2)3)6 ) presurgical embolization of these lesions decreases intraoperative blood loss and facilitates subsequent surgical resection.7)15)19 ) agents used for embolization of tumors include polyvinyl alcohol ( pva ) , gelfoam powder , fibrin glue , gelatin microspheres , liquid adhesives , alcohol and coils.4)11 ) until recently , pva particle embolization has served as the mainstay of embolization.4)11 ) onyx ( ev3 , plymouth , mn , usa ) is a nonpolymerizing liquid agent composed of ethylene - vinyl alcohol copolymer dissolved in dimethyl sulfoxide . we report the use of onyx in the embolization of vertebral body lesions , including a renal cell carcinoma vertebral body metastatic lesion and a vertebral hemangioma . a 74-year - old male patient with ongoing persistent lower lumbar spine pain , shortness of breath , and cough was initially treated symptomatically for his pain and for presumed pneumonia . computed tomography ( ct ) demonstrated an 11 mm right middle lobe lesion and an indeterminate 13 mm right adrenal lesion , prompting further evaluation with positron emission tomography ( pet)-ct . a pet - ct demonstrated a fluorodeoxyglucose ( fdg)-avid left renal mass suggestive of malignancy with an associated l2 vertebral body and left humeral head destructive lesion . he underwent total spine magnetic resonance imaging ( mri ) and lumbar spine ct imaging , revealing a large destructive l2 vertebral body lesion with a pathologic fracture and 4-mm soft tissue extension into the ventral spinal canal , resulting in moderate left - sided spinal canal narrowing ( fig . significant l2-l3 left subarticular zone , neural foraminal narrowing , and compression on the left traversing l3 and exiting l2 nerve roots were also identified . the patient was placed under general anesthesia and standard access with a 5 french sheath in the common femoral artery was achieved . a 5 french mickelson catheter ( cook medical inc . , bloomington , in , usa ) was employed to selectively catheterize the left l2 segmental artery and an angiographic run demonstrated an obvious pathologic blush in the region of the l2 vertebral body ( fig . an echelon microcatheter ( ev3 , plymouth , mn , usa ) was advanced through the mickelson catheter ( cook medical inc . , bloomington , in , usa ) into the distal left l2 segmental artery and onyx-18 ( ev3 , plymouth , mn , usa ) was injected , creating a cast within the segmental artery . the injected onyx-18 was allowed to reflux into the vertebral body until the metastatic lesion was completely embolized ( fig . the total fluoroscopy time for the procedure was 33 minutes , and the procedural duration was 2.5 hours . post - procedure plain x - ray films confirmed onyx distribution in the left half of the vertebral body , within the tumor ( fig . the patient subsequently underwent an uneventful corpectomy and fusion with minimal blood loss ( less than 100 cc ) and recovered without complications . a 52-year - old male patient presented with six months of progressive bilateral lower extremity weakness and worsening sensory function , leading to multiple falls . there were also spasms and spasticity of the lower extremities bilaterally , and several episodes of fecal and urinary incontinence . a ct and total spine mri revealed multiple lesions with coarse trabeculae in the thoracic ( t1 , t3 and t11 ) and lumbar spine ( l1 ) , most severe within the t3 vertebral body . these lesions extended to the posterior elements and soft tissues in the surrounding paravertebral and epidural space , causing significant anterior cord compression ( fig . an open biopsy confirmed an intraosseous hemangioma , and the patient was referred for embolization prior to anticipated surgical resection . the patient was placed under general anesthesia and standard access with a 5 french sheath in the common femoral artery was achieved . the right t4 segmental artery was selectively catheterized with a cobra catheter ( terumo , somerset , nj , usa ) . angiography demonstrated a large pathologic blush in the region of the t3 vertebral body , corresponding to the known hemangioma ( fig . an echelon microcatheter was advanced into the segmental artery and the vascular supply to the hemangioma was embolized with a total of 0.24 ml of onyx-18 ( fig . the procedural total fluoroscopy time was 27 minutes , and procedural duration was 2.5 hours . post - embolization angiography via the cobra catheter confirmed no further pathologic blush ( fig . the patient recovered uneventfully from the embolization and surgical resection , the latter with 300 cc of estimated blood loss . a 74-year - old male patient with ongoing persistent lower lumbar spine pain , shortness of breath , and cough was initially treated symptomatically for his pain and for presumed pneumonia . computed tomography ( ct ) demonstrated an 11 mm right middle lobe lesion and an indeterminate 13 mm right adrenal lesion , prompting further evaluation with positron emission tomography ( pet)-ct . a pet - ct demonstrated a fluorodeoxyglucose ( fdg)-avid left renal mass suggestive of malignancy with an associated l2 vertebral body and left humeral head destructive lesion . he underwent total spine magnetic resonance imaging ( mri ) and lumbar spine ct imaging , revealing a large destructive l2 vertebral body lesion with a pathologic fracture and 4-mm soft tissue extension into the ventral spinal canal , resulting in moderate left - sided spinal canal narrowing ( fig . significant l2-l3 left subarticular zone , neural foraminal narrowing , and compression on the left traversing l3 and exiting l2 nerve roots were also identified . the patient was placed under general anesthesia and standard access with a 5 french sheath in the common femoral artery was achieved . a 5 french mickelson catheter ( cook medical inc . , bloomington , in , usa ) was employed to selectively catheterize the left l2 segmental artery and an angiographic run demonstrated an obvious pathologic blush in the region of the l2 vertebral body ( fig . an echelon microcatheter ( ev3 , plymouth , mn , usa ) was advanced through the mickelson catheter ( cook medical inc . , bloomington , in , usa ) into the distal left l2 segmental artery and onyx-18 ( ev3 , plymouth , mn , usa ) was injected , creating a cast within the segmental artery . the injected onyx-18 was allowed to reflux into the vertebral body until the metastatic lesion was completely embolized ( fig . the total fluoroscopy time for the procedure was 33 minutes , and the procedural duration was 2.5 hours . post - procedure plain x - ray films confirmed onyx distribution in the left half of the vertebral body , within the tumor ( fig . the patient subsequently underwent an uneventful corpectomy and fusion with minimal blood loss ( less than 100 cc ) and recovered without complications . a 52-year - old male patient presented with six months of progressive bilateral lower extremity weakness and worsening sensory function , leading to multiple falls . there were also spasms and spasticity of the lower extremities bilaterally , and several episodes of fecal and urinary incontinence . a ct and total spine mri revealed multiple lesions with coarse trabeculae in the thoracic ( t1 , t3 and t11 ) and lumbar spine ( l1 ) , most severe within the t3 vertebral body . these lesions extended to the posterior elements and soft tissues in the surrounding paravertebral and epidural space , causing significant anterior cord compression ( fig . an open biopsy confirmed an intraosseous hemangioma , and the patient was referred for embolization prior to anticipated surgical resection . the patient was placed under general anesthesia and standard access with a 5 french sheath in the common femoral artery was achieved . the right t4 segmental artery was selectively catheterized with a cobra catheter ( terumo , somerset , nj , usa ) . angiography demonstrated a large pathologic blush in the region of the t3 vertebral body , corresponding to the known hemangioma ( fig . an echelon microcatheter was advanced into the segmental artery and the vascular supply to the hemangioma was embolized with a total of 0.24 ml of onyx-18 ( fig . the procedural total fluoroscopy time was 27 minutes , and procedural duration was 2.5 hours . post - embolization angiography via the cobra catheter confirmed no further pathologic blush ( fig . 5c , fig . the patient recovered uneventfully from the embolization and surgical resection , the latter with 300 cc of estimated blood loss . metastatic disease occurs in approximately 30% to 50% of patients with renal cell carcinoma at the time of initial diagnosis.9)15)16)18 ) approximately 40% of patients develop bone metastases.11 ) in addition to drug - based therapies such as bisphosphonates and denosumab for the treatment of osseous metastatic lesions , radiation therapy and surgery are important in the treatment of renal cell carcinoma bone metastases.18 ) these interventions are considered appropriate when there is mechanical instability , intractable pain , radiculopathy and pathologic fractures.11)13)15)18 ) surgical decompression and stabilization are the treatments of choice for radiation resistant metastatic spinal tumors.11)13)14 ) renal cell metastases to the vertebral bodies are , however , highly vascular and can cause life threatening bleeding.11)14)15 ) vertebral hemangiomas are also highly vascular intraosseous lesions , thought to occur in approximately 10% of all patients , most commonly in the thoracic and lumbar spine.5)6)10)17 ) these lesions are typically asymptomatic though they may enlarge , causing pain and neurological deficits secondary to spinal cord compression or pathological fractures.1)8 ) multiple studies have demonstrated safe and effective results from preoperative embolization of both spinal metastases of renal origin and vertebral hemangiomas . sundarasean et al . demonstrated successful results in the treatment of 17 patients who underwent selective spinal angiography and preoperative embolization with absolute ethyl alcohol in the treatment of spinal metastases.15 ) in 1999 , berkfield et al . verified the effectiveness of particle embolization , pva , in reducing perioperative hemorrhage prior to corporectomy in hypervascular spinal tumors.2 ) smith et al . demonstrated the safety and effectiveness of transarterial embolization of symptomatic vertebral hemangiomas in eight cases using pva.12 ) in 2013 , yao et al . described four cases of transpedicular n - butyl cyanoacrylate ( nbca ) direct - puncture embolization of spinal hemangiomas as a preoperative adjunct , facilitating resection of these high vascular tumors.19 ) were the first to document the use of onyx , transarterially , in the treatment of two cases of aggressive vertebral hemangiomas.6 ) additional studies report use of onyx via an arterial route and by direct puncture in the treatment of hypervascular head , neck and spinal tumors.4 ) advantages of onyx embolization include a more controlled injection due to gradual precipitation in a centripetal fashion , allowing for slower and more accurate injections as well as penetration of very small caliber vessels.4 ) in addition , it can be easily visualized during surgery via intraoperative x - rays and directly visualized , serving as a roadmap for the surgeon . as is done during particulate embolization , careful attention must be paid to the initial diagnostic angiographic run prior to embolization to ensure opacification of a spinal pial artery such as the artery of adamkiewicz is not seen . in both of our illustrative cases , 3 , reflux of onyx into the epidural venous plexus may occur without resultant morbidity . our results further the growing body of literature confirming the safety and efficacy of onyx embolization of vertebral body lesions .
while onyx embolization of cerebrospinal arteriovenous shunts is well - established , clinical researchers continue to broaden applications to other vascular lesions of the neuraxis . 
 this report illustrates the application of onyx ( ev3 , plymouth , mn ) embolization to vertebral body lesions , specifically , a vertebral hemangioma and renal cell carcinoma vertebral body metastatic lesion .