Spinal Cord Blood Supply Research Articles

Pre-operative spinal cord perfusion quantified by DSC MRI as a predictor of post-operative prognosis in patients with cervical spondylotic myelopathy.

This study aims to investigate the potential of preoperative blood supply condition measured by dynamic susceptibility contract (DSC) MRI in prediction of postoperative outcomes for patients with cervical spondylotic myelopathy (CSM). Thirty-nine patients (Age: 61 ± 7, male: 23, female: 16) with CSM who underwent laminoplasty were enrolled. All patients received DSC MRI before the operation. Five parameters include Enhance, rEnhance, full width at half maxima (FWHM), Slope1 and Slope2 in DSC MRI, were calculated at all the compressed spinal cord segments. Clinical outcomes were evaluated by modified Japanese Orthopaedic Association (mJOA) scores. Patients were divided into two groups based on mJOA recovery rate of 5years: good recovery (> 50%) or poor recovery (≤ 50%). The difference between two groups were compared. The value of DSC MRI to CSM was evaluated by logistic and receiver operating characteristic (ROC) curve analysis. There were 26 patients in good recovery group and 13 patients in poor recovery group. The baseline characteristics, including age, gender, preoperative mJOA score, and smoking status showed no significant difference between the two groups (all p > 0.05). The FWHM was significantly higher in the poor recovery group (9.77 ± 2.78) compared to the good recovery group (6.64 ± 1.65) (p = 0.002). Logistic regression analysis indicated that an increased FWHM was a significant risk factor for poor prognosis recovery (p = 0.013, OR = 0.392, 95%CI: 0.187-0.822). The AUC of FWHM for ROC was 0.843 (95% CI: 0.710-0.975) with a p value of 0.001. In addition, an FWHM greater than 5.87, with a sensitivity of 92.3% and specificity of 69.2%, was found to be an independent risk factor for poor postoperative recovery in patients with CSM. In this study, we successfully quantified the spinal cord blood supply condition by DSC MRI technique. We found that an increase in FWHM was an independent risk factor for poor postoperative recovery in CSM patients. Specifically, patients with FWHM > 5.87 have a poor postoperative recovery.

Clinical manifestations and magnetic resonance imaging features of spinal cord infarction

Background and ObjectiveSpinal cord infarction (SCI) is a rare type of stroke, with no proposed classification or diagnostic criterium widely accepted and used in daily clinical practice currently. We try to explore the clinical manifestations and MRI features of SCI for improving the accurate diagnosis of SCI. MethodsRetrospectively analyzed the clinical data, MRI features, laboratory findings and outcomes of 40 patients who had been consecutively diagnosed with SCI in our hospital from June 2016 to January 2022. ResultsMost of the SCI (92.5%) occurred at the level of T8-L2 and C4-T4. Transverse infarction (52.5%) and ASA territory infarction (27.5%) were the most common patterns. Longitudinally extensive lesions were noticed in 67.5% of the SCI and it might be a risk factor of poor prognosis (OR=21.11, 95%CI 2.14-208.29). Restricted diffusion of the SCI lesion occurred in 8h and a few lasted up to 60 days. All SCI showed spinal cord edema, accompanied by enhancement of the ventral cauda equina (13.8%), weakened enhancement of the dorsal venous plexus (44.8%), and vertebral infarction (25%). Most patients developed a stroke-like onset (92.5%) after movement (57.5%), with definite pain in the trunk or limbs (67.5%) and dissociative sensory disturbance (60.0%). The main etiologies of them include vascular abnormalities (45%) and iatrogenic injuries (15%). ConclusionAn MRI classification of SCI based on the spinal cord blood supply was proposed. Restricted diffusion and co-existing abnormality of vertebral body and cauda equina may be the key neuroimaging feature for SCI diagnosis. Detailed history of vascular diseases or triggering factors are also helpful.

Rationale of the PAPAartis trial.

Surgical and interventional repair of thoracoabdominal aortic aneurysms improve survival significantly compared to the natural history of the disease. However, both strategies are associated with a substantial risk of spinal cord ischemia, which has been reported to occur-even in contemporary series by expert centers-in up to 12% of patients, depending on the extent of the disease. Following improved neurological outcomes after staged approaches in extensive clinical and long-term large animal studies, and the description of the "collateral network", the concept of "Minimally Invasive Staged Segmental Artery Coil Embolization" (MIS2ACE) was introduced by Etz et al. This concept of priming the collateral network in order to improve spinal cord blood supply showed promising experimental and early clinical outcomes, and consequently led to the initiation of the randomized controlled multicenter PAPAartis trial (Paraplegia Prevention in Aortic Aneurysm Repair by Thoracoabdominal Staging). This Keynote Lecture describes the background and rationale for this trial and gives an update on the current status.

Unraveling the enigma of Adamkiewicz: exploring the prevalence, anatomical variability, and clinical impact in spinal embolization procedures for bone metastases.

The artery of Adamkiewicz (AKA) is vital for spinal cord blood supply. Its role in embolization procedures for bone metastases can cause serious complications. We explored its prevalence, anatomical variation, and effect on spinal embolization using N-butyl cyanoacrylate (NBCA) in patients with bone metastases. To understand the impact and variability of AKA in spinal embolizations in cases of bone metastases to reduce complications and improve patient outcomes. We examined data from 454 patients who underwent spinal embolization with NBCA between 2009 and 2018. The presence, anastomoses, and tumor features of AKA were assessed via pre-procedure imaging and angiography. Complications were classified per the CIRSE Classification System. AKA was found in 22.8% of patients, predominantly left-sided and originating from T8 to L1. Direct and indirect anastomoses were present in 66.6% and 33.4% of patients, respectively. Extra-compartmental invasion was linked with direct anastomosis (P = 0.004). High-grade complications were rare but included one instance of bilateral lower limb paralysis. Partial embolization was necessary in 22.8% of cases due to AKA. The study underscores the need for rigorous preoperative evaluation of AKA origin and anastomoses in patients undergoing spinal embolization for bone metastases. Given the significant presence of AKA and related anastomoses, especially with renal extra-compartmental tumors, caution is advised to reduce complications and optimize patient outcomes. Further research is required for best practice guidelines involving bone metastases and AKA.

Identification of the Magna Radicular Artery Entry Foramen and Adamkiewicz System: Patient Selection for Open versus Full-Endoscopic Thoracic Spinal Decompression Surgery.

Casually cauterizing the radicular magna during routine thoracic discectomy may have dire consequences. We performed a retrospective observational cohort study on patients scheduled for decompression of symptomatic thoracic herniated discs and spinal stenosis who underwent a preoperative computed tomography angiography (CTA) to assess the surgical risks by anatomically defining the foraminal entry level of the magna radicularis artery into the thoracic spinal cord and its relationship to the surgical level. Fifteen patients aged 58.53 ± 19.57, ranging from 31 to 89 years, with an average follow-up of 30.13 ± 13.42 months, were enrolled in this observational cohort study. The mean preoperative VAS for axial back pain was VAS of 8.53 ± 2.06 and reduced to a postoperative VAS of 1.60 ± 0.92 (p < 0.0001) at the final follow-up. The Adamkiewicz was most frequently found at T10/11 (15.4%), T11/12 (23.1%), and T9/10 (30.8%). There were eight patients where the painful pathology was found far from the AKA foraminal entry-level (type 1), three patients with near location (type 2), and another four patients needing decompression at the foraminal (type 3) entry-level. In five of the fifteen patients, the magna radicularis entered the spinal canal on the ventral surface of the exiting nerve root through the neuroforamen at the surgical level requiring a change of surgical strategy to prevent injury to this important contributor to the spinal cord's blood supply. The authors recommend stratifying patients according to the proximity of the magna radicularis artery to the compressive pathology with CTA to assess the surgical risk with targeted thoracic discectomy methods.

Laryngoscopy mediated stress response induces opposite effects on cerebral and paraspinal oxygen saturation

Background: Intraoperative sympathetic stimulation induces a cascade of metabolic and hormonal changes. It increases perfusion of vital organs, but also causes vasoconstriction of blood vessels supplying less vital organs, potentially leading to organ injury. To date, it is unknown how an endogenous stress reaction affects the spinal cord blood supply. Near-infrared spectroscopy (NIRS) can be applied paravertebrally to monitor the oxygenation of the collateral network, which contributes to the spinal cord blood supply. It has already been demonstrated that regional cerebral oxygen saturation (rScO2) increases following sympathetic stimulation. Objectives: We hypothesized that laryngoscopy would cause an increase in cerebral and paraspinal regional tissue saturations (rScO2 and rSpsO2, respectively). Design: Retrospective analysis of a previous conducted randomized trial. Setting: Laryngoscopy in the operating room. Methods: Data of 28 patients, scheduled for arterial dilation of the lower limb, were retrospectively analyzed. Before induction of anesthesia, standard monitoring, BIS and 8 NIRS sensors were applied (two on the forehead, six bilaterally on the back at T3-T4, T9-T10 and L1-L2). Sympathetic stimulation was induced by laryngoscopy. Main outcome measures: Changes in rStO2 following sympathetic stimulation induced by laryngoscopy. Results: Following laryngoscopy, rScO2 significantly increased and rSpsO2 significantly decreased at T9-T10 and L1-L2. The relative changes (regional tissue oxygen saturation (rStO2) after intubation-rStO2 before intubation)/ rStO2 before intubation), at cerebral level, T9-T10 and L1-L2 were 9%, -5% and -3%, respectively (p &lt; 0.01). rSpsO2 at T3-T4 did not change significantly. Changes (Δ) in mean arterial pressure following laryngoscopy were weakly correlated with ΔrScO2 and moderately correlated with ΔrSpsO2 at T9-T10 and L1-L2. Conclusions: Intraoperative sympathetic stimulation may decrease the oxygen supply to the spinal cord. Trial registration: The trial was registered at ClinicalTrials.gov (NCT 03767296).

THE ANESTHETIC MANAGEMENT OF EXTENSIVE AORTIC THORACIC ANEURYSM REPAIR WITH CLAMSHELL INCISION

Introduction Surgical repair of extensive thoracic aorta disease represents an interesting challenge, both surgical and anesthetic. We describe the surgical repair of an acute aortic dissection beginning in the aortic arch in relation with aortic coartation and a post coartation aneurism, and the aspects related to planning, management and perioperative care. The clamshell incision is associated with respiratory complications, bleeding and post-operative severe pain. Interruption of spinal cord blood supply is one of the causes of spinal cord injury after thoracic aortic aneurism repair. Aortic arch surgery requiring circulatory arrest bears significant risk of brain injury. Methods Descending aorta cannulation and perfusion, preservation of its posterior wall, lumbar paravertebral NIRS and femoral arterial invasive pressure monitoring were used as spinal cord protective strategies. Cerebral antegrade perfusion, initially unilateral and then bilateral, with BIS and cerebral NIRS monitoring were the key components of the cerebral protection strategy. A bilateral erector spinae plane block (BESPB) was performed to allow good pain control in the postoperative period, early extubation and rehabilitation. Intravenous antifibrinolytic, goal directed transfusion therapy and maintaining a coagulation friendly environment were the mainstays of the non-surgical hemostasis strategy. Results The patient was successfully extubated in the operating room presenting no neurological deficits. The surgical drains were removed on the fifth day; on the following day it was necessary to surgically remove part of the left thoracic drain, under combined anesthesia with the ipsilateral ESPB catheter. The remaining postoperative period was uneventful and the patient was discharged home in the 10th postoperative day. Discussion No subarachnoid catheter was placed (to drain cerebrospinal fluid to protect the spinal cord from ischemia), after discussing it in advance with the surgical team, given the risks associated with it and the protective strategy to be adopted: direct perfusion of the descending aorta, preservation of its posterior wall, lumbar paravertebral NIRS ant femoral arterial invasive pressure monitoring., in the intraoperative period, on table extubation and direct neurological monitoring, together with adequate systemic arterial pressures, in the immediate postoperative period. Good pain control with BESPB and on table extubation allowed for early rehabilitation

Detrimental effects of cerebrospinal fluid pressure elevation on spinal cord perfusion: first-time direct detection in a large animal model.

Cerebrospinal fluid (CSF) drainage is routinely utilized to mitigate perioperative and postoperative spinal cord ischaemia in open and endovascular thoraco-abdominal aortic aneurysm repair to prevent permanent paraplegia. Clinical decision-making in the vulnerable perioperative period, however, is still based on limited clinical and experimental data. Our aim was to investigate the isolated effect of CSF pressure elevation on spinal cord perfusion in an established large animal model. Ten juvenile pigs with normal (native) arterial inflow (patent segmental arteries and collaterals) underwent iatrogenic CSF pressure elevation (×2, ×3, ×4 from their individual baseline pressure). Each pressure level was maintained for 30 min to mimic clinical response time. After the quadrupling of CSF pressure, the dural sac was slowly depressurized against gravity allowing CSF pressure to passively return to baseline values. Measurements were taken 30 and 60 min after normalization, and microspheres for regional blood flow analysis were injected at each time point. Spinal cord perfusion decreased significantly at all mid-thoracic to lumbar cord segments at the doubling of CSF pressure and declined to values <53% compared to baseline when pressure was quadrupled. Normalizing CSF pressure led to an intense hyperperfusion of up to 186% at the cervical level and 151% within the lumbar region. CSF pressure elevation results in a relevant impairment of spinal cord blood supply. Close perioperative and postoperative monitoring of CSF pressure is crucial for maintaining sufficient spinal cord perfusion. Radical and rapid withdrawal of CSF is followed by significant hyperperfusion in all spinal cord segments and may lead to 'drainage-related' iatrogenic reperfusion injury-aggravating the risk of delayed spinal cord injury-and should therefore be avoided.

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.

Anatomy of the Great Posterior Radiculomedullary Artery.

Although considerable variability exists as to the overall caliber of radiculomedullary arteries, dominant radiculomedullary arteries such as the artery of Adamkiewicz exist. The existence of a great posterior radiculomedullary artery has attracted little attention and has been a matter of debate. The aim of this anatomic study was to determine the presence or absence of the great posterior radiculomedullary artery. We performed microsurgical dissection on formaldehyde-fixed cadaveric human spinal cords. The artery of Adamkiewicz in the spinal cord specimens (n = 50) was injected with colored latex until the small-caliber arterial vessels were filled and the great posterior radiculomedullary artery was identified. The course, diameter, and location of great posterior radiculomedullary artery were documented. A great posterior radiculomedullary artery was identified in 36 (72%) spinal cord specimens. In 11 (22%) specimens, bilateral great posterior radiculomedullary arteries were present. In 13 cases (26%), a unilateral left-sided great posterior radiculomedullary artery was identified. In 11 cases (22%), a unilateral right-sided great posterior radiculomedullary artery was identified. In 1 specimen (2%), 3 right-sided great posterior radiculomedullary arteries were noted. The average size of the great posterior radiculomedullary arteries was 0.44 mm (range, 0.120-0.678 mm on the left and 0.260-0.635 mm on the right). A great posterior radiculomedullary artery is present in most (72%) individuals. The authors describe the microsurgical anatomy of the great posterior radiculomedullary artery with emphasis on its morphometric parameters as well as its implications for spinal cord blood supply. Variations of the arterial supply to the dorsal cord are of great importance due to their implications for ischemic events, endovascular procedures, and surgical approaches.

Routine anterior spinal artery visualization prior to descending and thoracoabdominal aneurysm repair: High detection success.

Paraplegia is adevastating complication of open descending (DTAA) and thoracoabdominal aortic aneurysm (TAAA) repair. Despite major advances in imaging and surgical techniques, paraplegia continues to be problematic. We present our experience with routine application of enhanced imaging techniques to detect the anterior spinal artery (ASA) before DTAA and TAAA repair. We retrospectively reviewed 177 patients with DTAA and TAAA who underwent imaging to detect the ASA before open surgical repair. High definition CT angiography (CTA) and dual energy CT scanning (DECT) were our modalities of choice with angiography used earlier and magnetic resonance angiography (MRA) used when CT was contraindicated. Descriptive statistics and χ2 analyses were conducted. The imaging protocol successfully detected the level of the ASA in 132 (74.5%) patients, utilizing CTA in 67, DECT in 28, spinal angiography in 31, and MRA in 6. Cross sectional modalities with advanced visualization technique (CT, DECT, and MRA) were more successful at detecting the ASA than angiography (80.72%, 82.35%, 75% vs 59.62%, respectively, P = .04). Concerted efforts were made not to leave the operating room without continuity of the ASA with the circulation (via limited resection, beveled anastomosis, or reimplantation). Transient lower extremity weakness was observed in 11 (6.2%) patients, and permanent paraplegia in 2 (1.12%) patients. Modern imaging technology provides multiple methodologies highly successful at detecting the ASA. The ASA can then be preserved intraoperatively, contributing to low paraplegia rates. We strongly recommend routine application of this technology to arm the surgeon with precise information about the specific patient's spinal cord blood supply.

Impact of Intermittent Functional Internal Iliac Artery Occlusion on Spinal Cord Blood Supply During TEVAR

Impact of Intermittent Functional Internal Iliac Artery Occlusion on Spinal Cord Blood Supply During TEVAR

Impact of Intermittent Functional Internal Iliac Artery Occlusion on Spinal Cord Blood Supply during TEVAR.

Measuring transcranial motor evoked potentials (EPs) and somatosensory EPs is a well-established method to assess spinal cord function during thoracic endovascular aortic repair (TEVAR). Functional occlusion of one or both internal iliac arteries by large bore sheaths during TEVAR can cause unilateral intermittently EP loss. Between 2006 and 2016, 194 patients underwent TEVAR entailing EP monitoring. The ISIS IOM System (Inomed Medizintechnik GmbH, Emmendingen, Germany) was employed in all patients. EPs were recorded after inducing anesthesia, during the procedure, and before discontinuing anesthesia. We observed a unilateral intermittently EP decrease or loss in 12 (6.2%) patients. Most events were ipsilateral (9 of 12). The underlying pathologies were descending aortic aneurysm in six patients and type B dissection in six patients. An evoked-potential decrease or loss was always associated with the insertion of large bore stent-graft-introducing sheaths. The median duration of the unilaterally EP decrease or loss was 16 (10; 31) minutes (range, 2-77 minutes) with baseline values re-established at the end of the procedure after sheath removal in all cases. No patient developed irreversible symptomatic spinal cord ischemia. A functional occlusion of internal iliac arteries via large bore TEVAR-introducing sheaths is associated with a unilateral intermittent decrease in or loss of EPs returning to baseline after sheath removal. This observation highlights the importance of the internal iliac arteries as one of the major spinal cord's blood supply territories, and may serve as a stimulus to reduce the duration of sheath indwelling to a minimum.

Incomplete Cord Syndromes: Clinical and Imaging Review.

The ability to localize the three spinal tracts (corticospinal tract, spinothalamic tract, and dorsal [posterior] columns) involved in incomplete spinal cord syndromes at cross-sectional imaging and knowledge of the classic clinical manifestations of the various syndromes enable optimized imaging evaluation and provide clinicians with information that aids in diagnosis and treatment. The requisite knowledge for localizing these tracts is outlined. The authors review the spinal cord anatomy, blood supply, and course of these tracts and describe the various associated syndromes: specifically, dorsal cord, ventral cord, central cord, Brown-Séquard, conus medullaris, and cauda equina syndromes. In addition, they describe the anatomic basis for the clinical manifestation of each syndrome and the relevant imaging features of the classic causes of these entities. Knowledge of the anatomy and clinical findings of the spinal cord is essential for examining and treating patients with cord abnormalities. ©RSNA, 2018.

Changes in muscular strength based on full cervical flexion

We present our study of influence full cervical flexion position on the changes in muscle strength of the upper extremities. This position is typical for a person working on mobile phone or iPad. The purpose of the study was determination of the connection between change of the head flexed position and changes in upper extremity muscles strength. The present study involved 80 healthy volunteers and was performed at the Department of Morphology in Riga Stradins University, Riga, Latvia. For measurements we have used the MicroFET2 Hand Held Digital Muscle Tester to determine the strength of the muscles of the hand and arm (M. abductor pollicis longus, M. biceps brachii, M. triceps brachii, M. deltoideus). The results of measurements were then used to analyze the difference in the strength of the muscles innervated by the spinal cord cervical region (C5–C8 nerves) for the same person sitting in the vertical position and sitting with the head flexed maximally. The results of our study support the hypothesis that the changes in the strength of measured muscles are related to the mechanical distension of the spinal cord, which leads to changes in spinal cord's blood supply. The kyphotic position of the cervical spine during head flexion shows that in the spinal cord segments C5 and C7 are formed mechanical distension. Using our statistical study, we can conclude that there is strong relationship in the strength change in some of the observed muscles between vertical position and full flexion of head

Arterial Blood Supply to the Spinal Cord in Animal Models of Spinal Cord Injury. A Review.

Animal models are used to examine the results of experimental spinal cord injury. Alterations in spinal cord blood supply caused by complex spinal cord injuries contribute significantly to the diversity and severity of the spinal cord damage, particularly ischemic changes. However, the literature has not completely clarified our knowledge of anatomy of the complex three-dimensional arterial system of the spinal cord in experimental animals, which can impede the translation of experimental results to human clinical applications. As the literary sources dealing with the spinal cord arterial blood supply in experimental animals are limited and scattered, the authors performed a review of the anatomy of the arterial blood supply to the spinal cord in several experimental animals, including pigs, dogs, cats, rabbits, guinea pigs, rats, and mice and created a coherent format discussing the interspecies differences. This provides researchers with a valuable tool for the selection of the most suitable animal model for their experiments in the study of spinal cord ischemia and provides clinicians with a basis for the appropriate translation of research work to their clinical applications. Anat Rec, 300:2091-2106, 2017. © 2017 Wiley Periodicals, Inc.

The Cervical Arteries: An Anatomical Study with Application to Avoid the Nerve Root and Spinal Cord Blood Supply.

Injury to the vascular supply to the cervical spinal cord can lead to the anterior spinal artery syndrome, which is often associated with transforaminal corticosteroid injections to the cervical foramina. The purpose of this cadaveric study was to examine the morphology of the cervical arteries and to emphasize their clinical importance. Five formalin-fixed human cadavers were used to determine the morphology of the radicular arteries from the vertebral, ascending and deep cervical arteries in the cervical foraminal region. The mean diameter of the vertebral arteries was 5.50 mm. The radicular arteries arose from the vertebral artery originating from its posterior aspect at each level and the C6 radicular artery was larger in diameter than others. Their diameters ranged from 0.75 mm to 1.02 mm. The mean diameter of the ascending cervical artery was 1.5 mm (range 1.21 to 1.80 mm). Its arising spinal branches were located at the C3-4 or C4-5 levels. The diameters of radicular branches arising from the ascending cervical artery ranged from 0.80 mm to 1.40 mm. The mean diameter of the deep cervical artery was 1.71 mm (range 1.3 to 2.1 mm) and was usually slightly larger than the ascending cervical arteries. These deep cervical radicular arteries always entered the C5-6, C6-7 and C7-T1 foramens and those of the radicular branches arising from the deep cervical artery ranged from 0.43 mm to 1.49 mm (mean, 1.08 mm). Understanding the vascular supply to the cervical spinal cord is important for preventing serious complications such as spinal cord ischemia.

Ischemia and reperfusion injury of the spinal cord: experimental strategies to examine postischemic paraplegia

Thoracoabdominal aortic replacement, necessary in case of injuries, aneurysms and dissections, shows a high complication rate as a consequence of the perioperative ischemia / reperfusion-sequence (I/R). Clamping above and below the lesion leads to the spinal cord suffering from ischemia. Clamping times of less than 30 minutes show only a small risk of neurological deficit, while longer periods increase paraplegia rates disproportionately. The subsequent reperfusion as a second hit causes additional damage to the spinal cord. Up to 30 % of all patients who require being treated in the thoracoabdominal part of the aorta suffer from paraplegia within the first 24 postoperative hours (Kahn et al., 2012).

Anatomia da circulação medular

ResumoA intrincada anatomia tridimensional da irrigação medular é frequentemente explanada na literatura com diferentes nomenclaturas e devido a sua alta relevância no estudo da isquemia medular, o estudo da terminologia se faz necessário para melhor compreensão do tema. A artéria de Adamkiewicz, também chamada de artéria radicular magna, é a via principal. Foi realizada a revisão da literatura com equiparação das nomenclaturas utilizadas e elaboração de descrição acurada e sumarizada do conhecimento atual sobre a vascularização medular.

Invited Commentary

German researchers have always been very fond of enigmata. They even called one of the most sophisticated encrypting machines ever simply “Enigma.” It was first patented in 1918 and was used widely during the Second World War until its code system was finally broken at Bletchley Park [1Hinsley F.H. Stripp A. Codebreakers: The Inside Story of Bletchley Park. Oxford University Press, Oxford, UK1993Google Scholar]. One enigma still unsolved 70 years later is the blood supply of the spinal cord and its protection during operations on the thoracic or thoracoabdominal aorta. Interestingly enough, the crucial steps to understand both the Enigma machine and spinal cord blood supply were taken by Poles: Marian Rejewski and Albert Adamkiewicz, respectively. Pig models have been used for a long time for further understanding, despite of some basic anatomic differences [2Wadouh F. Arndt C.F. Metzger H. Hartmann M. Wadouh R. Borst H.G. Direct measurements of oxygen tension on the spinal cord surface of pigs after occlusion of the descending aorta.J Thorac Cardovasc Surg. 1985; 89: 787-794PubMed Google Scholar, 3Etz C.D. Kari F.A. Mueller C.S. et al.The collateral network concept: a reassessment of the anatomy of spinal cord perfusion.J Thorac Cardiovasc Surg. 2011; 141: 1020-1028Abstract Full Text Full Text PDF PubMed Scopus (212) Google Scholar]. An academic debate regarding the role of the so-called artery of Adamkiewicz [4Adamkiewicz A. Die Blutgefässe des menschlichen Rückenmarkes I: Die Gefässe der Rückenmarkssubstanz. Sitzungsberichte der kais. Akademie der Wissenschaften zu Wien.Math Naturwissenschaftl Classe. 1881; 84: 469-502Google Scholar, 5Adamkiewicz A. Die Blutgefässe des menschlichen Rückenmarkes II: Die Gefässe der Rückenmarlsoberfläche. Sitzungsberichte der kais. Akademie der Wissenschaften zu Wien.Math Naturwissenschaftl Classe. 1882; 85: 101-130Google Scholar] has been ongoing, including the respective protective approaches derived from the defended opinion [6Wadouh F. Arndt C.F. Oppermann E. Borst H.G. Wadouh R. The mechanism of spinal cord injury after simple and double aortic cross-clamping.J Thorac Cardiovasc Surg. 1986; 92: 121-127PubMed Google Scholar, 7Griepp R.B. Ergin M.A. Galla J.D. et al.Looking for the artery of Adamkiewicz: a quest to minimize paraplegia after operations for aneurysms of the descending thoracic and thoracoabdominal aorta.J Thorac Cardiovasc Surg. 1996; 112: 1202-1215Abstract Full Text Full Text PDF PubMed Scopus (247) Google Scholar, 8Heinemann M.K. Brassel F. Herzog T. Dresler C. Becker H. Borst H.G. The role of spinal angiography in thoracic aortic surgery: myth or reality?.Ann Thorac Surg. 1998; 65: 346-351Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar]. Now, Haldenwang and colleagues have applied the porcine model to simulate modern surgical strategies [9Haldenwang P.L. Prochnow N. Baumann A. et al.Spinal cord ischemia after selective cerebral perfusion in a porcine “frozen elephant trunk” simulation model.Ann Thorac Surg. 2015; 99: 1624-1631Google Scholar]. Given the background of the previous studies, it is not so surprising that the lower (lumbar) regions were more susceptible to ischemic damage even after indirect (selective cerebral) perfusion at moderate hypothermia (28°C). Some perfusion is probably almost always better than none, and the colder the better is still valid for tissue protection. This report nicely shows that even seemingly less invasive techniques such as endovascular stent-grafting are still troubled by one of the most enigmatic enigmata in medicine. Definitive deciphering is still bound to take a while, and it is to be hoped that this group will continue its valuable research. Spinal Cord Ischemia After Selective Cerebral Perfusion in a Porcine “Frozen Elephant Trunk” Simulation ModelThe Annals of Thoracic SurgeryVol. 99Issue 5PreviewThe “frozen elephant trunk” procedure (FET) represents the therapy of choice for extended aortic diseases. The aim of our study was to analyze whether 90 minutes of selective cerebral perfusion (SCP) at 28°C followed by permanent occlusion of the thoracic segmental arteries (TSA) would cause spinal cord ischemia in a porcine model. Full-Text PDF