Anterior Radiculomedullary Artery Research Articles

Occlusion of vertebral artery and anterior spinal artery in cervical facet dislocation: a prospective study using computed tomography angiography.

A prospective study. To investigate the incidence of vertebral artery (VA) occlusion and whether anterior spinal artery (ASA) is occluded in cervical facet dislocation. University hospital, China. During a 2-year period, 21 conventional patients with cervical facet dislocation were prospectively enrolled. All patients received computed tomography angiography (CTA) to assess the patency of the VA, anterior radiculomedullary arteries (ARAs), and ASA at the time of injury. Clinical data were documented, including demographics, symptomatic vertebrobasilar ischemia, American Spinal Injury Association Impairment Scale (ASIA) grades, and ASA and VA radiological characteristics. VA unilateral occlusion occurred in 5 of 21 patients (24%), including 2 with unilateral facet dislocation and 3 with bilateral facet dislocation. No ASA occlusion was found in all 21 patients, including 5 with VA unilateral occlusion. No patients had symptomatic vertebrobasilar ischemia. VA occlusion occurs in approximately one-fourth of cervical facet dislocations, with infrequent symptomatic vertebrobasilar ischemia. ASA is not occluded following cervical facet dislocation, even with unilateral VA occlusion.

Endovascular occlusion of segmental arteries feeding the anterior spinal artery to stage endovascular thoracoabdominal aortic repair

ObjectiveMinimally invasive segmental artery coil embolization was introduced to prevent spinal cord ischemia after endovascular repair of thoracoabdominal aortic aneurysms. There is no consensus on whether the endovascular occlusion of segmental arteries feeding directly the anterior radiculomedullary artery and anterior spinal artery can be safely performed without causing spinal cord ischemia. Our aim was to investigate the feasibility and clinical impact of endovascular occlusion of segmental arteries supplying the anterior spinal artery during minimally invasive segmental artery coil embolization in patients with thoracoabdominal aortic aneurysms. MethodsBetween January 2018 and July 2020, 54 patients (36 male; mean age, 71.1 ± 9.3 years) underwent direct embolization of segmental arteries feeding the anterior radiculomedullary artery before endovascular repair of thoracoabdominal aortic aneurysms. End points included technical success of minimally invasive segmental artery coil embolization of segmental arteries, anterior radiculomedullary artery, neurological complications, and in-hospital mortality after minimally invasive segmental artery coil embolization and endovascular repair of thoracoabdominal aortic aneurysms. ResultsThe thoracoabdominal aortic aneurysm classification was type I (n = 8), type II (n = 24), type III (n = 11), and type IV (n = 11). During minimally invasive segmental artery coil embolization, 388 segmental arteries were occluded, each patient having 7.2 ± 3.1 coiled segmental arteries occluding 64.5% (25-100%) of open segmental arteries within the treated aortic segment. Altogether, 66 anterior radiculomedullary arteries were seen originating between Th8 and L3 levels from 85 (21.9%) segmental arteries. In 10 patients (18.5%), 2 large anterior radiculomedullary arteries were identified, and 1 patient (1.9%) showed 3 anterior radiculomedullary arteries on the spinal arteriography. No spinal cord ischemia or procedure-related complications occurred after minimally invasive segmental artery coil embolization. After 47.9 ± 39.4 days, all patients received endovascular repair of their thoracoabdominal aortic aneurysms. There was no in-hospital mortality. One male patient developed incomplete temporary spinal cord ischemia after endovascular repair. ConclusionsMinimally invasive segmental artery coil embolization of segmental arteries feeding the anterior spinal artery in patients with thoracoabdominal aortic aneurysms to prevent spinal cord ischemia after endovascular repair is feasible and clinically safe.

Utility of intra-procedural cone-beam computed tomography imaging for the determination of the artery of Adamkiewicz suspected by angiography during transarterial embolization for hemoptysis.

To evaluate the role of cone-beam computed tomography (CT) performed for the determination of the artery of Adamkiewicz (AKA) suspected by angiography during trans-catheter bronchial artery embolization for hemoptysis. In this retrospective study, 17 patients with hemoptysis who underwent cone-beam CT for evaluation of the AKA prior to arterial embolization from December 2014 to March 2022 were included. During the angiographic session, two interventional radiologists selected the possible AKAs that were defined as obscured hairpin-curved vessels arising from the dorsal branch of the intercostal arteries and running towards the midline in the arterially enhanced phase. Contrast-enhanced cone-beam CT was performed as an adjunct to angiography to determine whether the indefinite AKA was a real AKA based on whether it was found to connect to the anterior spinal artery. Selective cone-beam CT was performed at 17 possible AKAs detected by selective arteriogram of the intercostal artery (ICA). Cone-beam CT allowed for the determination of AKAs in 16 cases (94.1%). As a result of cone-beam CT findings, 9 of 16 study arteries (56.3%) were judged as definite AKAs, and the remaining 7 (43.7%) were judged as definitely not AKAs but as the musculocutaneous branching from the dorsal branch of the ICA. In 1 of 17 cases (5.9%), cone-beam CT could not determine the AKA because of poor image quality caused by inadequate breath holding. An additional anterior radiculomedullary artery arising from the dorsal branch of the lower ICA because of the inflow of the contrast medium through the anastomosis was detected in one case by conebeam CT but not by angiography. Intraprocedural enhanced cone-beam CT performed as an adjunctive technique to angiography is sufficient for confident determination of the AKA, which is essential for the operators to perform accurate and safe arterial embolization for hemoptysis.

Feasibility of Direct Intercostal and Lumbar Artery Revascularization to Prevent Spinal Cord Ischemia Associated with Endovascular Thoracoabdominal Aortic Repair

Despite advances in complex endovascular aortic repair techniques, spinal cord ischemia (SCI) is still a devastating complication following endovascular thoracoabdominal aortic repairs. Current preventive strategies such as staged repair, temporary sac perfusion, hemodynamic management, and spinal drainage, focus on augmentation of spinal perfusion through collateral networks. Novel strategies to preserve key intercostal/lumbar arteries have been described including endovascular incorporation of fenestrations/branches and extra-anatomic bypass. We report our early results of patients who underwent direct intercostal/lumbar artery revascularization using endovascular or extra-anatomic approaches for fenestrated-branched endovascular aortic repairs (FBEVAR). A retrospective review of consecutive patients who underwent FBEVAR with intercostal/lumbar artery revascularization from 2018 to 2022 was performed. Patient characteristics, intraoperative details, and outcomes including SCI and branch occlusions were evaluated. Among 318 patients who underwent FBEVAR during the study period, 12 patients were included in the study. Aortic pathologies consisted of degenerative aneurysms (33%), postdissection aneurysms (33%), extensive penetrating aortic ulcers with intramural hematoma (25%), and visceral patch pseudoaneurysm (8%). Full thoracoabdominal coverage was required in eight patients and supraceliac coverage >10 cm was required in four. Nine patients received endovascular incorporation (Fig 1), including directional branches (5/9), unstented fenestrations (2/9), and stented fenestration (1/9). Three patients received extra-anatomic subcutaneous femoral-to-radicular artery bypass using a composite graft of polytetrafluoroethylene and saphenous vein (Fig 2). Our institutional SCI prevention protocol, consisting of prophylactic cerebral spinal fluid drain for high-risk patients, hemodynamic augmentation, and oxygen supplementation, was followed. Prophylactic cerebral spinal fluid drain was placed in nine patients. One patient had unsuccessful drain placement attempts. Two patients who had selective angiography identifying the great anterior radiculomedullary artery, did not undergo drain placement. Total number of target vessels for FBEVAR was 4.2 with a fluoroscopy time 66 ± 31 minutes, and contrast usage of 109 ± 51 mL. There were no in-hospital mortalities. One patient died of intracranial hemorrhage after sustaining a fall from a ladder 32 days after discharge. Tarlov grade II SCI were seen in two patients (one endovascular, one extra-anatomic bypass), which resolved before discharge. At median follow-up of 13 months (range, 13 days to 37 months), three patients had thrombosed intercostal/lumbar branches (one extra-anatomic bypass, two endovascular branches) with no new SCI symptoms. In patients at high risk for SCI undergoing FBEVAR, direct revascularization of an intercostal or lumbar artery is feasible using endovascular or extra-anatomic bypass approach. Further studies are planned to identify key contributing intercostal and lumbar arteries and optimization of revascularization strategies.Fig 2Extra-anatomic, profunda femoris to L1 radicular artery bypass using a composite polytetrafluoroethylene-saphenous vein conduit.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Feasibility of Noninvasive Diagnosis of Spinal Vascular Diseases Using Time-Resolved Angiography With Stochastic Trajectories.

Background and Purpose: To determine the feasibility of time-resolved angiography with stochastic trajectories (TWIST) in the diagnosis of spinal dural arteriovenous fistula (SDAVF) and perimedullary arteriovenous fistula (PAVF).Methods: A total of 11 negative patients with TWIST examination were retrospective analyzed and then 18 patients with suspected spinal vascular diseases underwent TWIST. For negative patients, Adamkiewicz artery (AKA), great anterior radiculomedullary vein (GARV) and anterior spinal artery (ASA) were retrospective analyzed. In patients, the results of TWIST were compared with those of DSA.Results: The displaying rates of the ASA, AKA and GARV in 11 negative patients were 100, 90.9, and 90.9%, respectively. The AKA and GARV were separated on TWIST. Of 18 patients, 11 and three were diagnosed with SDAVF and PAVF, respectively. The spinal cord vascular malformation diagnosed on TWIST was consistent with DSA with an excellent intermodality agreement (Kappa = 0.92, p < 0.001). The feeding artery and side of all 11 SDAVF patients were displayed on TWIST and the results were consistent with DSA. For PAVF patients, the feeding artery in two patients and the sides as displayed on TWIST were consistent with DSA.Conclusions: TWIST enables the differentiation of the spinal artery and vein and the differential diagnosis of SDAVF and PAVF.

Chapter 3 - Neurovascular anatomy: Spine

The arterial supply of the spinal cord is provided by the spinal branch of the cervical, thoracic, and lumbar intersegmental arteries. While supply is initially provided at each embryonic segment, only a few prominent anterior radiculomedullary arteries remain at the adult stage, including the arteries of the cervical and lumbosacral enlargements as well as a constant upper thoracic contributor. The spinal cord is surrounded by the vasocorona, an arterial network that includes several longitudinal anastomotic chains, notably the anterior and posterior spinal arteries, which respectively supply the central and peripheral components of the intrinsic vascularization. The intrinsic venous circulation is also divided into central and peripheral components. The perimedullary venous system includes several longitudinal anastomotic chains interconnected by the coronary plexus. The radiculomedullary veins loosely follow the spinal nerve roots on their way to the epidural plexus. Their point of passage through the thecal sac forms an important valve-like structure, the antireflux mechanism.

The intraspinal arterial collateral network: a new anatomical basis for understanding and preventing paraplegia during aortic repair.

The anatomical distribution pattern of epidural intraspinal arteries is not entirely understood but is likely to substantially impact maintaining perfusion during segmental artery sacrifice when treating acute and chronic thoraco-abdominal aortic diseases. We investigated the anatomical distribution pattern of intraspinal arteries. Twenty fresh, non-embalmed cadaveric human bodies were studied. Anatomical dissection and investigation of the epidural arterial network were performed according to a standardized protocol. We used a generalized mixed linear model to test whether the presence probability for certain vessels differed between vertebrae/segments. There was craniocaudal continuity of all ipsilateral longitudinal connections from T1 to L5 by the anterior radicular artery. The mean [±standard deviation (SD)] number of transverse anastomoses was 9.7 ± 2.1. The presence probability of transverse anastomoses along the spine was different between vertebrae (P < 0.0001). There were 2 distribution peaks along the spine: 1 peak around T4-T6 and 1 around T11. The mean (±SD) number of thoracic and lumbar anterior radiculomedullary arteries (ARMAs) was 3.0 ± 1.1. The probability of the presence of ARMAs along the spine was different for each vertebral segment (P < 0.0001). Between ARMAs there were gaps of up to a maximum of 9 vertebrae. All Adamkiewicz arteries were located caudally to T7. The median segment of the Adamkiewicz presence was T10/11. The epidural collateral network shows craniocaudal continuity. The number of transverse anastomoses is high. The number of ARMAs is low, and there is considerable variation in their distribution and offspring, which is highly likely to impact perfusion during segmental artery sacrifice when treating thoraco-abdominal aortic disease.

Analysis of spinal cord blood supply combining vascular corrosion casting and fluorescence microsphere technique: A feasibility study in an aortic surgical large animal model.

Spinal cord ischemia after cardiovascular interventions continues to be a devastating problem in modern surgery. The role of intraspinal vascular networks and anterior radiculomedullary arteries (ARMA) in preventing spinal cord ischemia is poorly understood. Landrace pigs (n = 30, 35.1 ± 3.9 kg) underwent a lateral thoracotomy. Fluorescent microspheres were injected into the left atrium and a reference sample was aspirated from the descending aorta. Repeated measurements of spinal cord and renal cortical blood flow from the left and right kidneys with three different microsphere colors in five pigs were taken to validate reproducibility. Spinal cord blood flow to the upper thoracic (T1-T4), mid-thoracic (T5-T8), lower thoracic (T9-T13), and lumbar (L1-L3) levels were determined. After euthanasia, we carried out selective vascular corrosion cast and counted the left and right ARMAs from levels T1-T13. Blood flow analysis of the left and right kidneys revealed a strong correlation (r = .94, p < .001). We detected more left than right ARMAs, with the highest prevalence at T4 (p < .05). The mean number of ARMAs was 8 ± 2. Their number in the upper thoracic region ranged from 2 to 7 (mean of 5 ± 1), while in the lower thoracic region they ranged from 0 to 5 (mean of 3 ± 1 [p < .001]). This study shows that combining fluorescence microsphere technique and vascular corrosion cast is well suited for assessing the blood flow and visualizing the arteries at the same time.

Detection of the artery of Adamkiewicz using multidetector row computed tomography in patients with spinal arteriovenous shunt disease.

PurposeTo plan a treatment strategy for a spinal arteriovenous shunt (SAVS), identifying the artery of Adamkiewicz (AKA) and its origin is indispensable. However, detecting the AKA is very difficult in patients with an SAVS when using computed tomography angiography (CTA) by the usual method to find the hairpin curved artery because dilated drainage veins nearly always coexist with the hairpin curved AKA. We designed a method to identify the AKA by focusing on the diameter and pathway of the anterior radiculomedullary arteries (RMAs).Material and methodsSeven consecutive patients with an SAVS were surveyed. They underwent contrast-enhanced CTA and conventional angiography from January 2009 to December 2012. Two readers evaluated the CTA images and assumed that the AKA was the artery that ran through the anterior portion of the neural foramen and continued to pass on the ventral side of the spinal cord.ResultsAmong the seven patients, nine AKAs were detected with conventional angiography. When using our method, seven AKAs and six AKAs were identified on CTA by Reader 1 and Reader 2, respectively. The average sensitivity was 72.3%, and the specificity, accuracy, positive predictive value, and negative predictive value were sufficiently high (i.e. > 85%) for both readers. The kappa value for detecting the AKA was 0.98.ConclusionsDetecting the origin of the AKA with CTA is challenging in patients with an SAVS. However, focusing on the diameter and pathway of the RMAs may allow successful identification.

ANTERIOR SPINAL CORD INFARCTION COMPLICATING BRONCHIAL ARTERY EMBOLIZATION IN A PATIENT WITH MASSIVE HEMOPTYSIS

SESSION TITLE: Wednesday Fellows Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM INTRODUCTION: Bronchial artery embolization (BAE) is a relatively safe and effective treatment for massive hemoptysis. The bronchial and spinal arterial supplies are intricately related and various anatomical variations exist. CASE PRESENTATION: A 57-year-old female presented with progressively worsening hemoptysis after a recent lung biopsy. One week prior to admission, the patient underwent biopsies of a left upper lobe mass as well as suspicious lesions in right middle lobe and right lower lobe. Upon arrival, the patient was intubated for acute hypoxic respiratory failure and underwent emergent 300-500 μm particle embolization of two left lobe branches and one right lobe branch arteries and the bleeding ceased. The patient was deeply sedated and paralyzed for 24 hours after the procedure in an attempt to preserve hemostasis. On day 3, the patient was successfully extubated. Neurological examination after extubation revealed complete paraplegia and impaired pinprick and light touch sensation distal to the T4-T5 level. Magnetic resonance imaging scan of the spinal cord was performed with and without Dotarem® contrast. Abnormal T2/STIR hyperintensity of the ventral cord was noted from levels T1-2 to the mid body of T6 suggestive of acute infarction. Supportive management was instituted including blood pressure augmentation and rehabilitation. DISCUSSION: The bronchial arteries typically originate from the descending thoracic aorta at the level of T5-T6 vertebrae. The ventral and dorsal portions of the spinal cord are supplied by arteries draining into the anterior and posterior spinal arteries respectively. At the thoracic level, anterior radiculomedullary (feeder) arteries anastomose with the anterior spinal artery. These arteries usually originate from the posterior intercostal artery or the intercostobronchial trunk. Rarely, the feeder arteries may arise from the bronchial artery itself. In these patients, particle embolization of bronchial artery may lead to inadvertent embolization of the feeder artery leading to anterior spinal cord infarction. In these patients, embolization can still be performed by advancing the catheter in the bronchial artery distal to the origin of the feeder artery [1]. However, the connection between bronchial and feeder arteries may not be angiographically visible initially but may become apparent as the bronchial artery is embolized. Intermittent angiograms during embolization may help identify these connections [2]. CONCLUSIONS: Anterior spinal cord infarction is a rare complication of BAE. Careful analysis of the vascular anatomy and intermittent angiography during embolization may help prevent this serious complication. Reference #1: Tanaka N, Yamakado K, Murashima S et al. Superselective bronchial artery embolization for hemoptysis with a coaxial microcatheter system. J Vasc Interv Radiol. 1997 Jan-Feb;8(1 Pt 1):65-70. Reference #2: Brown AC, Ray CE. Anterior Spinal Cord Infarction following Bronchial Artery Embolization. Semin Intervent Radiol. 2012 Sep;29(3):241-4. DISCLOSURES: No relevant relationships by Shailesh Balasubramanian, source=Web Response No relevant relationships by Sudhir Krishnan, source=Web Response No relevant relationships by Guramrinder Thind, source=Web Response

New insights into spinal cord ischaemia after thoracic aortic procedures: the importance of the number of anterior radiculomedullary arteries for surgical outcome.

Anterior radiculomedullary arteries (ARMAs) link dorsal segmental arteries and the intraspinal compartment of the spinal collateral network. The number of thoracic ARMA is highly variable from one person to another. The impact of the number of ARMAs on spinal cord perfusion during thoracic aortic procedures is unknown. We investigated the influence of the number of thoracic ARMAs on spinal cord perfusion in an aortic surgical large animal model. Twenty-six pigs were included (20 treatment animals, 6 sham animals, weight 34 ± 3 kg). The animals underwent ligation of the left subclavian artery and the thoracic segmental arteries via a left lateral thoracotomy with normothermia. After sacrifice, complete body perfusion with coloured cast resin was performed and the number of thoracic ARMAs was documented at autopsy. End points were spinal cord perfusion pressure, cerebrospinal fluid pressure, spinal cord blood flow (microspheres) and neurological outcome. Observation time was 3 h post-ligation. The numbers of thoracic ARMAs ranged between 3 (n = 1) and 13 (n = 1). The mean number was 8. Animals were grouped according to number of thoracic ARMA: 6-7 (5 animals), 8-10 (8 animals) and 11-13 (5 animals). A large number of thoracic ARMAs was linked to (i) a lower drop in spinal cord blood flow from baseline to post-clamp, (ii) the presence and increased magnitude of hyperaemia evident 3 h post-clamp (P < 0.001) and (iii) the presence of early hyperaemia starting immediately post-clamp in animals with 11 or more ARMA (P < 0.001). We showed that a large number of thoracic ARMA protects against spinal cord injury during descending aortic surgical procedures.1.

Spinal Ischemia in Thoracic Aortic Procedures: Impact of Radiculomedullary Artery Distribution

The aim of this study was to assess the influence of thoracic anterior radiculomedullary artery (tARMA) distribution on spinal cord perfusion in a thoracic aortic surgical model. Twenty-six pigs (34 ± 3 kg; study group, n= 20; sham group, n= 6) underwent ligation of the left subclavian artery and thoracic segmental arteries. End points were spinal cord perfusion pressure (SCPP), regional spinal cord blood flow (SCBF), and neurologic outcome with an observation time of 3 hours. tARMA distribution patterns tested for an effect on end points included (1) maximum distance between any 2 tARMAs within the treated aortic segment (0 or 1 segment = small-distance group; >1 segment= large-distance group) and (2) distance between the end of the treated aortic segment and the first distal tARMA (at the level of the distal simulated stent-graftend= group 0; gap of 1 or more segments= group ≥1). The number of tARMA ranged from 3 to 13 (mean, 8). In the large-distance group, SCBF dropped from 0.48 ± 0.16 mL/g/min to 0.3 ± 0.08 mL/g/min (p < 0.001). We observed no detectable SCBF drop in the small-distance group: 0.2 ± 0.05 mL/g/min at baseline to 0.23 ± 0.05 mL/g/min immediately after clamping (p= 0.147). SCBF increased from 0.201 ± 0.055 mL/g/min at baseline to 0.443 ± 0.051 mL/g/min at 3 hours postoperatively (p < 0.001) only in the small-distance group. We demonstrate experimental data showing that distribution patterns of tARMAs correlate with the degree of SCBF drop and insufficient reactive parenchymal hyperemia in aortic procedures. Individual ARMA distribution patterns along the treated aortic segment could help us predict the individual risk of spinal ischemia.

Spinal ischaemia after thoracic endovascular aortic repair with left subclavian artery sacrifice: is there a critical stent graft length?

Thoracic endovascular aortic repair (TEVAR) is used for treatment of thoracic aortic pathologies, but the covered stent graft can induce spinal ischaemia depending on the length used. The left subclavian artery contributes to spinal cord collateralization and is frequently occluded by the stent graft. Our objective was to investigate the impact of covered stent graft length on the risk of spinal ischaemia in the setting of left subclavian artery sacrifice. Twenty-six pigs (German country race, mean body weight 36 ± 4 kg) underwent simulated descending aortic TEVAR via left lateral thoracotomy, with left subclavian artery and thoracic segmental artery occlusion in normothermia. Animals were assigned to treatment groups according to simulated stent graft length: TEVAR to T8 (n = 4), TEVAR to T9 (n = 4), TEVAR to T10 (n = 4), TEVAR to T11 (n = 7) and TEVAR to T12 (n = 1) and a sham group (n = 6). End points included spinal cord perfusion pressure, cerebrospinal fluid pressure and spinal cord blood flow using fluorescent microspheres. There were no group differences in spinal cord perfusion pressure drop or in spinal cord perfusion pressure regeneration potential at 3 h after the procedure: from a baseline average of 75 mmHg (95% confidence interval 71-83 mmHg) to 73 mmHg (67-75 mmHg) at 3 h in Group T10 versus from a baseline average of 67 mmHg (95% CI 50-81 mmHg) to 65 mmHg (95% confidence interval 48-81 mmHg) in Group T8. There were no differences in the spinal cord blood flow courses over time in the different groups nor was there any difference in cerebrospinal fluid pressure levels and cerebrospinal fluid pressure dynamics between groups. However, we did observe local blood flow distribution to the spinal cord that was inhomogeneous depending on the distance between the simulated stent graft end and the first thoracic anterior radiculomedullary artery. The risk of spinal ischaemia after serial segmental artery occlusion does not depend on the distal extent of the aortic repair alone. Future attempts to allow patient risk stratification for spinal ischaemia need to focus on anterior radiculomedullary artery anatomy together with the extent of planned aortic repair.

Detection of the Adamkiewiczartery in computed tomography of the thorax and abdomen

The great anterior radiculomedullary artery, also known as the artery of Adamkiewicz (AKA), is a small-caliber vessel which arises from the intercostal or lumbar arteries branching out from the aorta. The aim of this study was to evaluate detection of the AKA, as well as its level and side of origin, with multi-slice contrast enhanced computed tomography (MSCT) of the abdomen and thorax performed during everyday clinical practice, and to compare the results with the literature. The study retrospectively evaluated 200 consecutive MSCT images of the thoracic and thoracoabdominal aorta performed at Wroclaw Medical University's Department of General and Interventional Radiology and Neuroradiology as part of normal clinical work-ups. The CT examinations were performed with a 64-slice CT scanner. Arterial-phase images were analyzed for detection of the AKA and for anatomical variants of the AKA. Recognition of the AKA was achieved in 43 of 200 patients (21.5%). Out of these 43 cases, the AKA originated on the left side in 36 instances (83.7%) - a significantly higher number than on the right side (only in 6 cases, 14%); in one case (2.3%) it arose from both sides (p < 0.05, T-test). Most of the AKAs (24 cases, 55.8%) originated on the left side at level T11 or T12. In 13 patients (30.2%) the AKA arose from T11 or from T12 intercostal arteries. The origin of the AKA varied greatly and ranged from T5 (2.3%) to L2 (2.3%). The AKA is characterized by left-side lateralization and is associated with a wide range of origin, from T5 to L2. Detection of the AKA is, relatively speaking, rarely possible in routine clinical CT in the arterial phase - only in 1/5 of the patients. Therefore it is necessary to perform dedicated, individual arterial phase bolus tracking enhancement CT scans from the T5 to L3 level.

Intraforaminal Location of Thoracolumbar Radicular Arteries Providing an Anterior Radiculomedullary Artery Using Flat Panel Catheter Angiotomography.

Flat panel catheter angiotomography performed during the selective injection of intersegmental arteries offers a multiplanar assessment of the intraforaminal course of the radicular arteries providing an anterior radiculomedullary artery. Injury of anterior radiculomedullary arteries during transforaminal epidural steroid injections can result in spinal cord damage. Evaluations of the intraforaminal location of these arteries have so far been limited to anteroposterior views or the examination of cadaveric material. This study documents the in vivo intraforaminal location of thoracolumbar arteries providing an anterior radiculomedullary artery with flat panel catheter angiotomography. Ninety-four flat panel catheter angiotomography acquisitions obtained during the selective injection of intersegmental arteries providing an anterior radiculomedullary artery were reviewed. Measurements obtained from sagittal reconstructions were converted into a scatterplot visualization. Patients' age, sex, and side and level of the injection were recorded. The location of radicular arteries could be ascertained in 78 of 94 flat panel catheter angiotomography acquisitions (33 women and 45 men, 22-82 years of age). Fifty-three acquisitions (67.9%) were on the left side, and 25 (32.1%), on the right, between T2 and L3. The arteries were found in the anterosuperior quadrant of the neural foramen in 75 cases (96.2%), in the posterosuperior quadrant in 2 cases (2.6%), and in the anteroinferior quadrant in 1 case (1.3%). None were located in the posteroinferior quadrant. No differences in location were observed with age, sex, side of injection, or vertebral level. Avoiding needle placement in the superior half of the neural foramen, specifically the anterosuperior quadrant, can reduce the risk of spinal cord injury during transforaminal epidural steroid injection.

New Insights into Spinal Cord Ischemia after Thoracic Aortic Procedures: The Importance of Anterior Radiculo-Medullary Artery Anatomy for Surgical Outcome

New Insights into Spinal Cord Ischemia after Thoracic Aortic Procedures: The Importance of Anterior Radiculo-Medullary Artery Anatomy for Surgical Outcome

Intraoperative monitoring for spinal radiculomedullary artery aneurysm occlusion treatment: What, when, and how long?

Background:Spinal radiculomedullary artery aneurysms are extremely rare. Treatment should be tailored to clinical presentation, distal aneurysm flow, and lesion anatomical features. When a surgical occlusion is planned, it is necessary to evaluate whether intraoperative monitoring (IOM) should be considered as an indispensable tool to prevent potential spinal cord ischemia.Methods:We present a patient with symptoms and signs of spinal subarachnoid hemorrhage resulting from the rupture of a T4 anterior radiculomedullary aneurysm who underwent open surgical treatment under motor evoked potential (MEP) monitoring.Results:Due to the aneurysmal fusiform shape and preserved distal flow, the afferent left anterior radiculomedullary artery was temporarily clipped; 2 minutes after the clamping, the threshold stimulation level rose higher than 100 V, and at minute 3, MEPs amplitude became attenuated over 50%. This was considered as a warning criteria to leave the vessel occlusion. The radiculomedullary aneurysm walls were reinforced and wrapped with muscle and fibrin glue to prevent re-bleeding. The patient awoke from general anesthesia without focal neurologic deficit and made an uneventful recovery with complete resolution of her symptoms and signs.Conclusion:This paper attempts to build awareness of the possibility to cause or worsen a neurological deficit if a radiculomedullary aneurysm with preserved distal flow is clipped or embolized without an optimal IOM control. We report in detail MEP monitoring during the occlusion of a unilateral T4 segmental artery that supplies an anterior radiculomedullary artery aneurysm.

Porcine aortic surgical model to study isolated intraspinal collateralization

The function of the intraspinal collateral system, which includes repetitive epidural arcades and anterior radiculomedullary arteries, is not well understood in the setting of segmental artery ligation during aortic surgery. The animal model presented here can be used to characterize the function of the intraspinal collateral backup system in detail. BACKGROUND The incidence of spinal cord ischemia during extensive aortic surgery is still reported to be as high as 15% to 20%. Preoperative risk prediction according to individual collateral anatomy is not currently possible. The porcine model has been established as a valuable opportunity to study spinal collateral physiology in an aortic surgical setting. 1 The intraspinal compartment of the spinal collateral network includes a serial pattern of circular arcades and anterior radiculomedullary arteries (ARMAs) 1 and has not yet been functionally characterized. We postulate an important contribution of this system to immediate recovery of a sufficient spinal cord perfusion pressure directly after serial occlusion of segmental vessels. We sought to createalargeanimalmodelwithspinalcollateralflowbeing exclusively delivered through the intraspinal system. In a proof-of-concept study, a shutdown of thoracic and lumbar paraspinous inflow was achieved through percutaneous ethanol ablation of dorsal segmental arteries. The goal was to create a model suitable for investigation of the intraspinal collateral system in isolation, to understand more clearly its role in maintaining adequate spinal cord perfusion during aortic surgery.

Is the "snake-eye" MRI sign correlated to anterior spinal artery occlusion on CT angiography in cervical spondylotic myelopathy and amyotrophy?

The goal of this study was to identify anterior spinal artery (ASA) occlusion by CT angiography in cervical spondylotic myelopathy (CSM) and amyotrophy (CSA) with T2-weighted hyperintensity of MR image of documented small intramedullary high signal intensity known as "snake-eye appearance" (SEA). One hundred and six patients with CSM were admitted to the investigator group between June 2010 and June 2013. Intramedullary high signal intensity was found in 42 cases and was divided into two types, SEA and non-SEA. SEA was observed in 10 patients, including seven CSM patients and three CSA patients. All SEA patients were performed CT angiography of ASA after admission. The ASA was visualized in all 10 patients. ASA incomplete occlusion was found in one CSA patient and one CSM patient. No ASA occlusion was found in other CSA and CSM patients with SEA. ASA occlusion is not commonly seen in CSM and CSA patients with SEA. Pathological changes about SEA in CSM and CSA have no close correlation with ASA occlusion, but may be with anterior radiculomedullary arteries.

Focal Compression of the Upper Left Thoracic Intersegmental Arteries as a Potential Cause of Spinal Cord Ischemia

This study was prompted by recurrent angiographic observations of focal stenoses involving the proximal segment of the left upper thoracic intersegmental arteries, a few centimeters distal to their origin. The purpose was to investigate the nature and prevalence of this anomaly. The existence of non-ostial thoracic intersegmental artery stenoses was evaluated in 50 angiograms; the contribution of stenosed branches to the anterior spinal artery was recorded. Angiograms performed in 3 patients with right-sided aortas were also reviewed. The topographic relationships of the upper thoracic intersegmental artery with surrounding structures were investigated in 3 cadavers. Thirty-seven non-ostial stenoses were found in 26 patients (52%), predominantly on the left side (92%), between T3 and T8, most frequently at T4 and T5 (54%). Severe lesions were observed in 10% of cases. Patients with stenoses had fewer detectable anterior radiculomedullary arteries between T3 and T5 (35% versus 54%). Upper intersegmental artery stenoses, documented on the left side of all 3 specimens, appeared to be caused by the recurrent path of these intersegmental arteries related to the leftward position of the thoracic aorta, and by their course around reinforced paramedian longitudinal strands of the endothoracic fascia. Upper thoracic intersegmental artery stenoses are frequent. They result from the leftward deviation of the descending aorta and the existence of a fixed point along the course of the intersegmental arteries related to the endothoracic fascia. Because contributors to the spinal vascularization often originate at similar levels, these stenoses may play a role in the susceptibility of the upper and midthoracic spinal cord to ischemia.