Materiały źródłowe

• #1 Spinal Arteriovenous Malformation: Case Report and Review of the Literature – PMC Lock

  https://pmc.ncbi.nlm.nih.gov/articles/PMC7752798/

  Spinal arteriovenous malformations (AVMs) are a rare form of spinal blood vessel defect that results in vessel engorgement leading to clinical signs secondary to mass effect and ischemia. […] The mechanism of the development of spinal AVMs is not completely understood; however, the majority occur at birth rather than later in life. […] Due to the shunting of arteriole blood to the venous system without capillary access and resistance, over 70% of arterial pressure is transmitted to the venous system. […] Venous hypertension can precipitate many neurological deficits secondary to mass effect and normal spinal blood flow disruption along with increased risk for hemorrhage.

• #2 Arteriovenous malformation – Wikipedia

  https://en.wikipedia.org/wiki/Arteriovenous_malformation

  An AVM interferes with this process by forming a direct connection of the arteries and veins, bypassing the capillary bed. […] AVMs can cause intense pain and lead to serious medical problems. Although AVMs are often associated with the brain and spinal cord, they can develop in other parts of the body. […] As an AVM lacks the dampening effect of capillaries on the blood flow, the AVM can get progressively larger over time as the amount of blood flowing through it increases, forcing the heart to work harder to keep up with the extra blood flow. […] It also causes the surrounding area to be deprived of the functions of the capillaries. The resulting tangle of blood vessels, often called a nidus, has no capillaries. […] It can be extremely fragile and prone to bleeding because of the abnormally direct connections between high-pressure arteries and low-pressure veins.

• #3 Arteriovenous Malformations and Fistulas (AVM/AVF) of the Spinal Cord: Practice Essentials, Background, History of the Procedure

  https://emedicine.medscape.com/article/248456-overview

  Spinal arteriovenous malformations (AVMs) are a rare form of spinal blood vessel defect in which blood is received from the spinal feeding arteries, resulting in vessel engorgement that leads to clinical signs secondary to mass effect and ischemia. They account for about 10-15% of all spinal vascular shunts. Because of the rarity of spinal AVMs, studies regarding their diagnosis and treatment are limited. In addition, the various classifications that have been proposed historically make it difficult for young neurosurgeons to understand this disease. Because delayed initial diagnosis leads to irreversible damage to the spinal cord, neurosurgeons should always consider spinal AVM as part of the differential diagnosis. To understand the pathologic condition of spinal AVM, it is important to learn its basic classifications. Spinal AVM is classified as intradural, dural, and epidural. Spinal digital subtraction angiography (DSA) is the gold standard for diagnosis of spinal AVM and is an indispensable tool for treatment planning. […]

• #4 Spinal arteriovenous malformation (AVM) – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/spinal-arteriovenous-malformation/symptoms-causes/syc-20355613

  A spinal arteriovenous malformation (AVM) is a tangle of blood vessels that forms on, in or near the spinal cord. This creates irregular connections between arteries and veins. Without treatment, this rare condition can cause lasting damage to the spinal cord. […] But in a spinal AVM, the blood passes directly from the arteries to the veins. This change in blood flow means that the surrounding cells don’t get the oxygen they need. This can cause cells in the spinal tissue to weaken or die. […] The tangled arteries and veins in a spinal AVM also can burst and cause bleeding in the spinal cord. Sometimes, the AVM gets bigger as blood flow increases. The AVM can press on the spinal cord and cause weakness or other symptoms. […] The cause of spinal arteriovenous malformations (AVMs) isn’t known. Most spinal AVMs are present at birth, known as congenital. But others may happen later in life.

• #5 Arteriovenous Malformations of the Central Nervous System – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK531479/

  Arteriovenous malformations (AVMs) are abnormal fistulas between arteries and veins without an intervening capillary bed. High arterial flow directly into venous structures can lead to disruption of the venous walls and ultimately cause fatal hemorrhage. […] Though the exact mechanism of AVM formation is not fully understood, they are believed to form secondary to an abnormal arrest during embryologic vascular development. Approximately 5% of AVMs are identified in patients with inherited disorders such as autosomal dominant hereditary hemorrhagic telangiectasia, also known as Osler-Weber-Rendu syndrome. […] Multiple genetic mutations have been noted in patients with sporadic AVMs, including somatic activating KRAS mutations, the stop-gain mutation in SMAD9, and an increase in Notch-3 receptor expression. Increased KRAS activity leads to increased MAPK/ERK pathway activity with downstream elevations in Notch signaling and angiogenesis factors.

• #6 SPINAL CORD ARTERIOVENOUS MALFORMATIONS | PPT

  https://www.slideshare.net/slideshow/spinal-cord-arteriovenous-malformations/74670411

  Spinal arteriovenous malformation (AVM) is an abnormal tangle of arteries and veins in which the arteries feed directly into the veins with abnormal intervening capillary bed. […] AV fistula (AVF): direct communication between artery vein AV malformations (AVMs): multiple complex communications. […] Pathophysiology AV shunting result in venous engorgement and venous hypertension involving the spinal cord (Venous congestion, steal phenomenon, ischemia and hemorrhage). […] Most often, no direct arterial supply to the spinal cord itself originates from the radicular artery feeding an SDAVF. […] Vascular steal mechanism: High-flow lesion; AVM nidus acts as a low-resistance sump siphoning blood away from the surrounding normal spinal cord. […] Dysmorphic vessels susceptible to hemorrhage.

• #7 Vascular Malformations of the Brain and Spine in Children | PM&R KnowledgeNow

  https://now.aapmr.org/vascular-malformations-of-the-brain-and-spine-in-children/

  Arteriovenous malformations (AVMs) are congenital vascular lesions. They are characterized by an abnormal connection between arteries and veins that lack an intervening capillary bed, which results in direct arteriovenous shunting. AVMs are thought to have multifactorial causes, including genetic manipulation and angiogenic stimulation. Most theories suggest either persistence of a primitive arteriovenous connection or the development of such after the initial closure of the primitive connection. Other theories suggest that AVMs develop due to deranged vessel growth, remodeling dysfunction at the capillary-venous junction, or fistulization of cerebral venous angiomas. […] There is a structural defect in the formation of the arteriolar capillary network that is normally present between arteries and veins. Due to the absence of capillary communication, shunting elevates intraluminal venous pressure and produces ectasia and muscularization that form hybrid vessels and a vascular network called a nidus (nidal-type) or mainly a direct connection between the artery and the vein (fistulous-type). Over time, the lesion enlarges due to pressure differentials. Hemorrhage is thought to be due to the non-static nature of the AVMs and the rapid expansion that can occur during times of growth, possibly related to angiogenic/vascular growth factors. Hemorrhage occurs in 0.5% of cases of cranial AVMs and is more common with the fistulous type.

• #8 Challenging dogma: report of a spinal cord arteriovenous malformation as an acquired lesion in a pediatric patient in: Journal of Neurosurgery: Spine Volume 32 Issue 2 (2019) Journals

  https://thejns.org/spine/view/journals/j-neurosurg-spine/32/2/article-p302.xml

  Spinal cord intramedullary arteriovenous malformations (AVMs) have classically been considered congenital lesions that are present from birth. […] Interestingly, while many authors have demonstrated the development of de novo nidus-type brain AVMs, there have been no reported cases of a de novo intramedullary or perimedullary AVM of the spine. […] Potential pathophysiological mechanisms for the development of de novo vascular malformations of the spinal cord are discussed. […] Current dogma holds that spinal AVMs are congenital lesions that develop in utero. […] To date there have been no reported cases of a de novo nidus-type spinal AVM within or on the surface of the spinal cord. […] We report the first case of a de novo nidus-type perimedullary SCAVM. […] A majority of these lesions present with hemorrhage, usually due to rupture of an intranidal aneurysm.

• #9 Challenging dogma: report of a spinal cord arteriovenous malformation as an acquired lesion in a pediatric patient in: Journal of Neurosurgery: Spine Volume 32 Issue 2 (2019) Journals

  https://thejns.org/spine/view/journals/j-neurosurg-spine/32/2/article-p302.xml

  The remainder of these lesions present with a focal myelopathy secondary to either local venous congestion or local arterial steal phenomenon. […] It is generally believed that most patients with cerebral parenchymal AVMs have some genetic susceptibility to AVM formation, whether it be in the form of a germline mutation (as in hereditary hemorrhagic telangiectasia) or a somatic mutation (as in the recently described KRAS pathway for sporadic AVMs). […] In our particular case, we hypothesize that the patients syrinx may have been an angiogenic stimulus as it could have altered venous hemodynamics in the cord immediately rostral to the syrinx and triggered a vascular remodeling event, leading to the formation of an SCAVM. […] This theory is supported by prior studies that have demonstrated that venous hypertension stimulates the production of vascular endothelial growth factor, which has been implicated in AVM pathogenesis. […] Our finding of the first case of a de novo SCAVM debunks the notion that SCAVMs are necessarily congenital lesions. Further studies are needed to understand the pathogenesis of these lesions.

• #10 Arteriovenous Malformations of the Central Nervous System – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK531479/

  Arteriovenous malformations (AVMs) are abnormal fistulas between arteries and veins without an intervening capillary bed. High arterial flow directly into venous structures can lead to disruption of the venous walls and ultimately cause fatal hemorrhage. […] Though the exact mechanism of AVM formation is not fully understood, they are believed to form secondary to an abnormal arrest during embryologic vascular development. Approximately 5% of AVMs are identified in patients with inherited disorders such as autosomal dominant hereditary hemorrhagic telangiectasia, also known as Osler-Weber-Rendu syndrome. […] Multiple genetic mutations have been noted in patients with sporadic AVMs, including somatic activating KRAS mutations, the stop-gain mutation in SMAD9, and an increase in Notch-3 receptor expression. Increased KRAS activity leads to increased MAPK/ERK pathway activity with downstream elevations in Notch signaling and angiogenesis factors.

• #11 Arteriovenous Malformations of the Central Nervous System – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK531479/

  Arteriovenous malformations (AVMs) are abnormal fistulas between arteries and veins without an intervening capillary bed. High arterial flow directly into venous structures can lead to disruption of the venous walls and ultimately cause fatal hemorrhage. […] Though the exact mechanism of AVM formation is not fully understood, they are believed to form secondary to an abnormal arrest during embryologic vascular development. Approximately 5% of AVMs are identified in patients with inherited disorders such as autosomal dominant hereditary hemorrhagic telangiectasia, also known as Osler-Weber-Rendu syndrome. […] Multiple genetic mutations have been noted in patients with sporadic AVMs, including somatic activating KRAS mutations, the stop-gain mutation in SMAD9, and an increase in Notch-3 receptor expression. Increased KRAS activity leads to increased MAPK/ERK pathway activity with downstream elevations in Notch signaling and angiogenesis factors.

• #12 Arteriovenous Malformations of the Central Nervous System | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/17848

  Though the exact mechanism of AVM formation is not fully understood, they are believed to form secondary to an abnormal arrest during embryologic vascular development. […] Multiple genetic mutations have been noted in patients with sporadic AVMs, including somatic activating KRAS mutations, the stop-gain mutation in SMAD9, and an increase in Notch-3 receptor expression. […] Increased KRAS activity leads to increased MAPK/ERK pathway activity with downstream elevations in Notch signaling and angiogenesis factors. […] A significantly lower level of SMAD9 in AVM vessels was observed, as well as a decrease in SMAD4 phosphorylation. […] In 2015, Hill-Fellberg et al discovered a significant increase in Notch-3 receptor expression in AVM vasculature compared to brain samples without AVM. […] Arteriovenous malformations are abnormal arterial to venous structural connections without capillaries or intervening cortical tissue. AVMs demonstrate nonphysiological hemodynamics, which affects the structure of the vessels within; they are typically high-flow, low-resistance shunts. Elevated hydrostatic pressure is a postulated contributing risk to hemorrhage. […] Spinal AVMs may rupture due to vascular instability. Arterialized venous architecture leads to vascular hypertension, which then exerts a mass effect on surrounding neural tissues and ischemic injury, leading to progressive myelopathy, paresthesias, motor deficits, or bowel or bladder dysfunction.

• #13 Arteriovenous Malformations of the Central Nervous System | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/17848

  Though the exact mechanism of AVM formation is not fully understood, they are believed to form secondary to an abnormal arrest during embryologic vascular development. […] Multiple genetic mutations have been noted in patients with sporadic AVMs, including somatic activating KRAS mutations, the stop-gain mutation in SMAD9, and an increase in Notch-3 receptor expression. […] Increased KRAS activity leads to increased MAPK/ERK pathway activity with downstream elevations in Notch signaling and angiogenesis factors. […] A significantly lower level of SMAD9 in AVM vessels was observed, as well as a decrease in SMAD4 phosphorylation. […] In 2015, Hill-Fellberg et al discovered a significant increase in Notch-3 receptor expression in AVM vasculature compared to brain samples without AVM. […] Arteriovenous malformations are abnormal arterial to venous structural connections without capillaries or intervening cortical tissue. AVMs demonstrate nonphysiological hemodynamics, which affects the structure of the vessels within; they are typically high-flow, low-resistance shunts. Elevated hydrostatic pressure is a postulated contributing risk to hemorrhage. […] Spinal AVMs may rupture due to vascular instability. Arterialized venous architecture leads to vascular hypertension, which then exerts a mass effect on surrounding neural tissues and ischemic injury, leading to progressive myelopathy, paresthesias, motor deficits, or bowel or bladder dysfunction.

• #14 Arteriovenous Malformations of the Central Nervous System | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/17848

  Though the exact mechanism of AVM formation is not fully understood, they are believed to form secondary to an abnormal arrest during embryologic vascular development. […] Multiple genetic mutations have been noted in patients with sporadic AVMs, including somatic activating KRAS mutations, the stop-gain mutation in SMAD9, and an increase in Notch-3 receptor expression. […] Increased KRAS activity leads to increased MAPK/ERK pathway activity with downstream elevations in Notch signaling and angiogenesis factors. […] A significantly lower level of SMAD9 in AVM vessels was observed, as well as a decrease in SMAD4 phosphorylation. […] In 2015, Hill-Fellberg et al discovered a significant increase in Notch-3 receptor expression in AVM vasculature compared to brain samples without AVM. […] Arteriovenous malformations are abnormal arterial to venous structural connections without capillaries or intervening cortical tissue. AVMs demonstrate nonphysiological hemodynamics, which affects the structure of the vessels within; they are typically high-flow, low-resistance shunts. Elevated hydrostatic pressure is a postulated contributing risk to hemorrhage. […] Spinal AVMs may rupture due to vascular instability. Arterialized venous architecture leads to vascular hypertension, which then exerts a mass effect on surrounding neural tissues and ischemic injury, leading to progressive myelopathy, paresthesias, motor deficits, or bowel or bladder dysfunction.

• #15 Arteriovenous Malformations—Current Understanding of the Pathogenesis with Implications for Treatment

  https://www.mdpi.com/1422-0067/22/16/9037

  To develop novel effective therapeutic strategies for AVM treatment, a better understanding of the pathogenesis of AVM formation is paramount. […] A three-event hypothesis suggesting concurrence of two additional, regionally confined triggers, is mainly based on insights gained from animal studies. […] These studies suggested that a combination of a loss of one functional allele in an HHT-locus, a local loss of protein, and an angiogenic stimulus directed towards ECs might be required for AVM development in mice. […] Furthermore, determinants such as blood flow and shear stress have been identified to be contributory to AVM formation. […] Further research will be required to strengthen our understanding of AVM formation, and translate these insights from animal models to humans.

• #16 Arteriovenous Malformations—Current Understanding of the Pathogenesis with Implications for Treatment

  https://www.mdpi.com/1422-0067/22/16/9037

  To develop novel effective therapeutic strategies for AVM treatment, a better understanding of the pathogenesis of AVM formation is paramount. […] A three-event hypothesis suggesting concurrence of two additional, regionally confined triggers, is mainly based on insights gained from animal studies. […] These studies suggested that a combination of a loss of one functional allele in an HHT-locus, a local loss of protein, and an angiogenic stimulus directed towards ECs might be required for AVM development in mice. […] Furthermore, determinants such as blood flow and shear stress have been identified to be contributory to AVM formation. […] Further research will be required to strengthen our understanding of AVM formation, and translate these insights from animal models to humans.

• #17 Spinal arteriovenous malformation (AVM) – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/spinal-arteriovenous-malformation/symptoms-causes/syc-20355613

  A spinal arteriovenous malformation (AVM) is a tangle of blood vessels that forms on, in or near the spinal cord. This creates irregular connections between arteries and veins. Without treatment, this rare condition can cause lasting damage to the spinal cord. […] But in a spinal AVM, the blood passes directly from the arteries to the veins. This change in blood flow means that the surrounding cells don’t get the oxygen they need. This can cause cells in the spinal tissue to weaken or die. […] The tangled arteries and veins in a spinal AVM also can burst and cause bleeding in the spinal cord. Sometimes, the AVM gets bigger as blood flow increases. The AVM can press on the spinal cord and cause weakness or other symptoms. […] The cause of spinal arteriovenous malformations (AVMs) isn’t known. Most spinal AVMs are present at birth, known as congenital. But others may happen later in life.

• #18 Neurosurgical Consultants: Spine Disorders: Spinal Arteriovenous Malformations

  https://www.neurosurgerydallas.com/2_2_2_11.php

  ETIOLOGY […] The precise cause of Spinal Cord Arteriovenous Malformations has never been clearly defined. Malformations that arise within the Dural Sheath and within the parenchyma (substance) of the Spinal Cord are usually found in younger patients. These are generally believed to be Congenital in origin. When Arteriovenous Malformations are found in older patients, they are usually associated with some form of trauma. The term used for this malformation is an Arteriovenous Fistula (AVF). These AVF malformations develop when a Spinal Radicular (Nerve Root) Artery forms an abnormal arteriovenous communication (known as a „fistula”) with the venous Medullary Vein circulation of the Spinal Cord. The high-pressure arterial blood flow from the Radicular Artery causes a dilatation of the Spinal Cord’s venous system which is weaker and thinner walled compared to the artery. This results in slower flow within the veins, a condition known as venous stasis. In turn this venous outflow obstruction then causes ischemic changes to the surrounding and adjacent Spinal Cord tissue. This hypo-perfusion results in impaired neural function. The progressive venous engorgement, as well as the Spinal Cord ischemia, appears to conspire to produce Neurologic compromise of Spinal Cord function. […] Congenital intradural Spinal AVMs consist of a tangle of abnormal vessels. There appears to be a progressive recruitment of arterial blood vessels and thin-walled venous vessels. Once the high-flow arterial system overcomes the capacity of the abnormal venous vessels, hemorrhage occurs.

• #19 Challenging dogma: report of a spinal cord arteriovenous malformation as an acquired lesion in a pediatric patient in: Journal of Neurosurgery: Spine Volume 32 Issue 2 (2019) Journals

  https://thejns.org/spine/view/journals/j-neurosurg-spine/32/2/article-p302.xml

  The remainder of these lesions present with a focal myelopathy secondary to either local venous congestion or local arterial steal phenomenon. […] It is generally believed that most patients with cerebral parenchymal AVMs have some genetic susceptibility to AVM formation, whether it be in the form of a germline mutation (as in hereditary hemorrhagic telangiectasia) or a somatic mutation (as in the recently described KRAS pathway for sporadic AVMs). […] In our particular case, we hypothesize that the patients syrinx may have been an angiogenic stimulus as it could have altered venous hemodynamics in the cord immediately rostral to the syrinx and triggered a vascular remodeling event, leading to the formation of an SCAVM. […] This theory is supported by prior studies that have demonstrated that venous hypertension stimulates the production of vascular endothelial growth factor, which has been implicated in AVM pathogenesis. […] Our finding of the first case of a de novo SCAVM debunks the notion that SCAVMs are necessarily congenital lesions. Further studies are needed to understand the pathogenesis of these lesions.

• #20 Challenging dogma: report of a spinal cord arteriovenous malformation as an acquired lesion in a pediatric patient in: Journal of Neurosurgery: Spine Volume 32 Issue 2 (2019) Journals

  https://thejns.org/spine/view/journals/j-neurosurg-spine/32/2/article-p302.xml

  The remainder of these lesions present with a focal myelopathy secondary to either local venous congestion or local arterial steal phenomenon. […] It is generally believed that most patients with cerebral parenchymal AVMs have some genetic susceptibility to AVM formation, whether it be in the form of a germline mutation (as in hereditary hemorrhagic telangiectasia) or a somatic mutation (as in the recently described KRAS pathway for sporadic AVMs). […] In our particular case, we hypothesize that the patients syrinx may have been an angiogenic stimulus as it could have altered venous hemodynamics in the cord immediately rostral to the syrinx and triggered a vascular remodeling event, leading to the formation of an SCAVM. […] This theory is supported by prior studies that have demonstrated that venous hypertension stimulates the production of vascular endothelial growth factor, which has been implicated in AVM pathogenesis. […] Our finding of the first case of a de novo SCAVM debunks the notion that SCAVMs are necessarily congenital lesions. Further studies are needed to understand the pathogenesis of these lesions.

• #21 Challenging dogma: report of a spinal cord arteriovenous malformation as an acquired lesion in a pediatric patient in: Journal of Neurosurgery: Spine Volume 32 Issue 2 (2019) Journals

  https://thejns.org/spine/view/journals/j-neurosurg-spine/32/2/article-p302.xml

  The remainder of these lesions present with a focal myelopathy secondary to either local venous congestion or local arterial steal phenomenon. […] It is generally believed that most patients with cerebral parenchymal AVMs have some genetic susceptibility to AVM formation, whether it be in the form of a germline mutation (as in hereditary hemorrhagic telangiectasia) or a somatic mutation (as in the recently described KRAS pathway for sporadic AVMs). […] In our particular case, we hypothesize that the patients syrinx may have been an angiogenic stimulus as it could have altered venous hemodynamics in the cord immediately rostral to the syrinx and triggered a vascular remodeling event, leading to the formation of an SCAVM. […] This theory is supported by prior studies that have demonstrated that venous hypertension stimulates the production of vascular endothelial growth factor, which has been implicated in AVM pathogenesis. […] Our finding of the first case of a de novo SCAVM debunks the notion that SCAVMs are necessarily congenital lesions. Further studies are needed to understand the pathogenesis of these lesions.

• #22 Spinal arteriovenous malformation (AVM) – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/spinal-arteriovenous-malformation/symptoms-causes/syc-20355613

  A spinal arteriovenous malformation (AVM) is a tangle of blood vessels that forms on, in or near the spinal cord. This creates irregular connections between arteries and veins. Without treatment, this rare condition can cause lasting damage to the spinal cord. […] But in a spinal AVM, the blood passes directly from the arteries to the veins. This change in blood flow means that the surrounding cells don’t get the oxygen they need. This can cause cells in the spinal tissue to weaken or die. […] The tangled arteries and veins in a spinal AVM also can burst and cause bleeding in the spinal cord. Sometimes, the AVM gets bigger as blood flow increases. The AVM can press on the spinal cord and cause weakness or other symptoms. […] The cause of spinal arteriovenous malformations (AVMs) isn’t known. Most spinal AVMs are present at birth, known as congenital. But others may happen later in life.

• #23 Spinal Arteriovenous Malformation: Case Report and Review of the Literature – PMC Lock

  https://pmc.ncbi.nlm.nih.gov/articles/PMC7752798/

  Spinal arteriovenous malformations (AVMs) are a rare form of spinal blood vessel defect that results in vessel engorgement leading to clinical signs secondary to mass effect and ischemia. […] The mechanism of the development of spinal AVMs is not completely understood; however, the majority occur at birth rather than later in life. […] Due to the shunting of arteriole blood to the venous system without capillary access and resistance, over 70% of arterial pressure is transmitted to the venous system. […] Venous hypertension can precipitate many neurological deficits secondary to mass effect and normal spinal blood flow disruption along with increased risk for hemorrhage.

• #24 Neurosurgical Consultants: Spine Disorders: Spinal Arteriovenous Malformations

  https://www.neurosurgerydallas.com/2_2_2_11.php

  ETIOLOGY […] The precise cause of Spinal Cord Arteriovenous Malformations has never been clearly defined. Malformations that arise within the Dural Sheath and within the parenchyma (substance) of the Spinal Cord are usually found in younger patients. These are generally believed to be Congenital in origin. When Arteriovenous Malformations are found in older patients, they are usually associated with some form of trauma. The term used for this malformation is an Arteriovenous Fistula (AVF). These AVF malformations develop when a Spinal Radicular (Nerve Root) Artery forms an abnormal arteriovenous communication (known as a „fistula”) with the venous Medullary Vein circulation of the Spinal Cord. The high-pressure arterial blood flow from the Radicular Artery causes a dilatation of the Spinal Cord’s venous system which is weaker and thinner walled compared to the artery. This results in slower flow within the veins, a condition known as venous stasis. In turn this venous outflow obstruction then causes ischemic changes to the surrounding and adjacent Spinal Cord tissue. This hypo-perfusion results in impaired neural function. The progressive venous engorgement, as well as the Spinal Cord ischemia, appears to conspire to produce Neurologic compromise of Spinal Cord function. […] Congenital intradural Spinal AVMs consist of a tangle of abnormal vessels. There appears to be a progressive recruitment of arterial blood vessels and thin-walled venous vessels. Once the high-flow arterial system overcomes the capacity of the abnormal venous vessels, hemorrhage occurs.

• #25 Spinal arteriovenous malformations

  https://www.scielo.org.mx/article_plus.php?pid=S1665-50442021000200077&tlng=en&lng=es

  sAVMs represent an abnormal, often tiny, arteriovenous shunt located within the dura of the spinal cord. […] Blood flow through the fistula runs through a radicular vein in a retrograde manner to the coronal and pial venous plexus, which becomes dilated and tortuous. Outflow impairment to the epidural drainage system or blockage of venous return in the cava system explains this venous dilatation. […] Venous congestion is now recognized as a primary source of neurologic disability with sAVMs. Recent studies have validated the elevated pressure in the draining vein as a causative agent in myelopathy, and shown pathologic correlates, including hyalinized small blood vessels, perivascular/intraparenchymal lymphocytic infiltration, glial cell proliferation, and neuronal degeneration. […] Although impairment of venous drainage from the spinal cord parenchyma is most significant at the level of the shunt, the spread of venous hypertension in the cranial and caudal directions causes damage to the cord over a long distance. […] Hemorrhage can also precipitate neurologic decline: 25% of sAVMs patients will present with a ruptured lesion, as evidenced by subarachnoid hemorrhage (SAH), intraparenchymal hemorrhage, or a combination.

• #26 Spinal arteriovenous malformations

  https://www.scielo.org.mx/article_plus.php?pid=S1665-50442021000200077&tlng=en&lng=es

  sAVMs represent an abnormal, often tiny, arteriovenous shunt located within the dura of the spinal cord. […] Blood flow through the fistula runs through a radicular vein in a retrograde manner to the coronal and pial venous plexus, which becomes dilated and tortuous. Outflow impairment to the epidural drainage system or blockage of venous return in the cava system explains this venous dilatation. […] Venous congestion is now recognized as a primary source of neurologic disability with sAVMs. Recent studies have validated the elevated pressure in the draining vein as a causative agent in myelopathy, and shown pathologic correlates, including hyalinized small blood vessels, perivascular/intraparenchymal lymphocytic infiltration, glial cell proliferation, and neuronal degeneration. […] Although impairment of venous drainage from the spinal cord parenchyma is most significant at the level of the shunt, the spread of venous hypertension in the cranial and caudal directions causes damage to the cord over a long distance. […] Hemorrhage can also precipitate neurologic decline: 25% of sAVMs patients will present with a ruptured lesion, as evidenced by subarachnoid hemorrhage (SAH), intraparenchymal hemorrhage, or a combination.

• #27 Arteriovenous Malformations and Fistulas (AVM/AVF) of the Spinal Cord: Practice Essentials, Background, History of the Procedure

  https://emedicine.medscape.com/article/248456-overview

  Spinal malformations can be separated into 2 subgroups: AVMs and AVFs. Spinal arteriovenous malformations (AVMs) are a rare form of spinal blood vessel defect that results in vessel engorgement leading to clinical signs secondary to mass effect and ischemia. These lesions represent an abnormal connection between the spinal radicular artery and the medullary vein of the spinal cord. This type of fistula creates a slow-flow vascular malformation that typically develops over months to years. High-pressure arterial flow from the radicular artery dilates the perimedullary venous system, causing venous stasis and hypertension. Venous hypertension results in a decreased arteriovenous gradient. The end result consists of venous outflow obstruction, hypoperfusion, and hypoxia of the spinal cord. Neurologic compromise is thought to occur secondary to this venous engorgement and resultant spinal cord ischemia. […]

• #28 Spinal arteriovenous malformations

  https://www.scielo.org.mx/article_plus.php?pid=S1665-50442021000200077&tlng=en&lng=es

  sAVMs represent an abnormal, often tiny, arteriovenous shunt located within the dura of the spinal cord. […] Blood flow through the fistula runs through a radicular vein in a retrograde manner to the coronal and pial venous plexus, which becomes dilated and tortuous. Outflow impairment to the epidural drainage system or blockage of venous return in the cava system explains this venous dilatation. […] Venous congestion is now recognized as a primary source of neurologic disability with sAVMs. Recent studies have validated the elevated pressure in the draining vein as a causative agent in myelopathy, and shown pathologic correlates, including hyalinized small blood vessels, perivascular/intraparenchymal lymphocytic infiltration, glial cell proliferation, and neuronal degeneration. […] Although impairment of venous drainage from the spinal cord parenchyma is most significant at the level of the shunt, the spread of venous hypertension in the cranial and caudal directions causes damage to the cord over a long distance. […] Hemorrhage can also precipitate neurologic decline: 25% of sAVMs patients will present with a ruptured lesion, as evidenced by subarachnoid hemorrhage (SAH), intraparenchymal hemorrhage, or a combination.

• #29 Spinal arteriovenous malformations | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/spinal-arteriovenous-malformations?lang=us

  Spinal arteriovenous malformations (AVMs) are characterized by arteriovenous shunting with a true nidus. They represent ~25% of spinal vascular malformations. […] Both surgery and angioembolisation have a role in the treatment of spinal AVMs. […] Myelopathy from venous congestion/hypertension. […] Hemorrhage: within the cord parenchyma or subarachnoid space. […] High-flow AVMs may cause arterial steal from adjacent spinal cord segments. […] Myelopathy from large AVMs (rare).

• #30 Conus medullary arteriovenous malformation mimicking intramedullary tumor: a case report | The Egyptian Journal of Neurology, Psychiatry and Neurosurgery | Full Text

  https://ejnpn.springeropen.com/articles/10.1186/s41983-022-00553-y

  Vascular malformation of the spine accounted for 34% of all intradural lesions. Spinal arteriovenous malformation (AVM) is often missed because of overlapping symptoms with other pathology and ambiguous imaging. […] Spinal arteriovenous malformation (AVM) is a type of vascular malformation of the spine composed of nidus with draining vein and feeding artery, accounting for 34% of all intradural spinal cord tumours. […] Despite advances in neuroimaging technology, vascular lesion diagnosis is often missed, because the symptoms usually overlap with more frequent cases of myelopathy, such as neoplasms and other spinal degenerative diseases. […] If left untreated, spinal AVM could cause significant and progressive neurological disability in a short time. […] Multiple theories may explain the pathophysiology of how neurological symptoms may occur from AVM. Abnormal blood flow from the artery to the nidus and vein without going through the capillary causes pressure from the artery to be transmitted directly through the vein. This phenomenon will lead to stagnation of blood flow resulting in impaired spinal cord venous drainage and venous hypertension. Venous hypertension is then sent to all valveless intrinsic veins in the spinal cord, resulting in a decrease in the arteriovenous pressure gradient in the spinal cord, decreased tissue perfusion, and progressive deterioration of spinal cord function. […] Another known pathophysiology of neurological deficit in spinal AVM is mass effect, haemorrhage, or vascular steal phenomenon. […] Myelopathy and claudication may occur due to ischemia caused by the stealing phenomenon of the AVM, venous hypertension, mass effect, and haemorrhage.

• #31 SPINAL CORD ARTERIOVENOUS MALFORMATIONS | PPT

  https://www.slideshare.net/slideshow/spinal-cord-arteriovenous-malformations/74670411

  Spinal arteriovenous malformation (AVM) is an abnormal tangle of arteries and veins in which the arteries feed directly into the veins with abnormal intervening capillary bed. […] AV fistula (AVF): direct communication between artery vein AV malformations (AVMs): multiple complex communications. […] Pathophysiology AV shunting result in venous engorgement and venous hypertension involving the spinal cord (Venous congestion, steal phenomenon, ischemia and hemorrhage). […] Most often, no direct arterial supply to the spinal cord itself originates from the radicular artery feeding an SDAVF. […] Vascular steal mechanism: High-flow lesion; AVM nidus acts as a low-resistance sump siphoning blood away from the surrounding normal spinal cord. […] Dysmorphic vessels susceptible to hemorrhage.

• #32 Arteriovenous malformation – Wikipedia

  https://en.wikipedia.org/wiki/Arteriovenous_malformation

  An AVM interferes with this process by forming a direct connection of the arteries and veins, bypassing the capillary bed. […] AVMs can cause intense pain and lead to serious medical problems. Although AVMs are often associated with the brain and spinal cord, they can develop in other parts of the body. […] As an AVM lacks the dampening effect of capillaries on the blood flow, the AVM can get progressively larger over time as the amount of blood flowing through it increases, forcing the heart to work harder to keep up with the extra blood flow. […] It also causes the surrounding area to be deprived of the functions of the capillaries. The resulting tangle of blood vessels, often called a nidus, has no capillaries. […] It can be extremely fragile and prone to bleeding because of the abnormally direct connections between high-pressure arteries and low-pressure veins.

• #33 Spinal arteriovenous malformations

  https://www.scielo.org.mx/article_plus.php?pid=S1665-50442021000200077&tlng=en&lng=es

  sAVMs represent an abnormal, often tiny, arteriovenous shunt located within the dura of the spinal cord. […] Blood flow through the fistula runs through a radicular vein in a retrograde manner to the coronal and pial venous plexus, which becomes dilated and tortuous. Outflow impairment to the epidural drainage system or blockage of venous return in the cava system explains this venous dilatation. […] Venous congestion is now recognized as a primary source of neurologic disability with sAVMs. Recent studies have validated the elevated pressure in the draining vein as a causative agent in myelopathy, and shown pathologic correlates, including hyalinized small blood vessels, perivascular/intraparenchymal lymphocytic infiltration, glial cell proliferation, and neuronal degeneration. […] Although impairment of venous drainage from the spinal cord parenchyma is most significant at the level of the shunt, the spread of venous hypertension in the cranial and caudal directions causes damage to the cord over a long distance. […] Hemorrhage can also precipitate neurologic decline: 25% of sAVMs patients will present with a ruptured lesion, as evidenced by subarachnoid hemorrhage (SAH), intraparenchymal hemorrhage, or a combination.

• #34 Vascular Malformations of the Brain and Spine in Children | PM&R KnowledgeNow

  https://now.aapmr.org/vascular-malformations-of-the-brain-and-spine-in-children/

  AVM is the most unpredictable vascular malformation. It usually remains quiescent in childhood but tends to enlarge with time and cause local destruction. Acute hemorrhagic events in children have been associated with up to a 25% mortality rate. A hemorrhagic presentation is a significant independent predictor of future hemorrhage. The annual risk of rebleeding in children is 24% but may be up to 65% when projected over the child’s lifespan. […] AVMs are often an incidental finding versus a catastrophic presentation due to rupture/hemorrhage, making prediction of outcomes difficult. Once neurological deficit occurs, focus is on prevention of symptom worsening with secondary measures. Once rupture or hemorrhage occurs, there is an increased risk of recurrence, especially in the first year. Nidus-type spinal cord AVMs had lower complete obliteration rates that may cause delayed rebleeding and clinical progression from hemorrhage to myelopathy and long-term deterioration. […] The Spetzler-Martin (SM) grading scale is utilized as a decision tool to estimate the risk of surgical resection by evaluating the AVM size, pattern of venous drainage and eloquence of brain location, with higher grades of 4 and 5 being associated with greater surgical morbidity and mortality.

• #35 Challenging dogma: report of a spinal cord arteriovenous malformation as an acquired lesion in a pediatric patient in: Journal of Neurosurgery: Spine Volume 32 Issue 2 (2019) Journals

  https://thejns.org/spine/view/journals/j-neurosurg-spine/32/2/article-p302.xml

  Spinal cord intramedullary arteriovenous malformations (AVMs) have classically been considered congenital lesions that are present from birth. […] Interestingly, while many authors have demonstrated the development of de novo nidus-type brain AVMs, there have been no reported cases of a de novo intramedullary or perimedullary AVM of the spine. […] Potential pathophysiological mechanisms for the development of de novo vascular malformations of the spinal cord are discussed. […] Current dogma holds that spinal AVMs are congenital lesions that develop in utero. […] To date there have been no reported cases of a de novo nidus-type spinal AVM within or on the surface of the spinal cord. […] We report the first case of a de novo nidus-type perimedullary SCAVM. […] A majority of these lesions present with hemorrhage, usually due to rupture of an intranidal aneurysm.

• #36 Challenging dogma: report of a spinal cord arteriovenous malformation as an acquired lesion in a pediatric patient in: Journal of Neurosurgery: Spine Volume 32 Issue 2 (2019) Journals

  https://thejns.org/spine/view/journals/j-neurosurg-spine/32/2/article-p302.xml

  Spinal cord intramedullary arteriovenous malformations (AVMs) have classically been considered congenital lesions that are present from birth. […] Interestingly, while many authors have demonstrated the development of de novo nidus-type brain AVMs, there have been no reported cases of a de novo intramedullary or perimedullary AVM of the spine. […] Potential pathophysiological mechanisms for the development of de novo vascular malformations of the spinal cord are discussed. […] Current dogma holds that spinal AVMs are congenital lesions that develop in utero. […] To date there have been no reported cases of a de novo nidus-type spinal AVM within or on the surface of the spinal cord. […] We report the first case of a de novo nidus-type perimedullary SCAVM. […] A majority of these lesions present with hemorrhage, usually due to rupture of an intranidal aneurysm.

• #37 Spinal arteriovenous malformation (AVM) – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/spinal-arteriovenous-malformation/symptoms-causes/syc-20355613

  A spinal arteriovenous malformation (AVM) is a tangle of blood vessels that forms on, in or near the spinal cord. This creates irregular connections between arteries and veins. Without treatment, this rare condition can cause lasting damage to the spinal cord. […] But in a spinal AVM, the blood passes directly from the arteries to the veins. This change in blood flow means that the surrounding cells don’t get the oxygen they need. This can cause cells in the spinal tissue to weaken or die. […] The tangled arteries and veins in a spinal AVM also can burst and cause bleeding in the spinal cord. Sometimes, the AVM gets bigger as blood flow increases. The AVM can press on the spinal cord and cause weakness or other symptoms. […] The cause of spinal arteriovenous malformations (AVMs) isn’t known. Most spinal AVMs are present at birth, known as congenital. But others may happen later in life.

• #38 Spinal arteriovenous malformation (AVM) – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/spinal-arteriovenous-malformation/symptoms-causes/syc-20355613

  A spinal arteriovenous malformation (AVM) is a tangle of blood vessels that forms on, in or near the spinal cord. This creates irregular connections between arteries and veins. Without treatment, this rare condition can cause lasting damage to the spinal cord. […] But in a spinal AVM, the blood passes directly from the arteries to the veins. This change in blood flow means that the surrounding cells don’t get the oxygen they need. This can cause cells in the spinal tissue to weaken or die. […] The tangled arteries and veins in a spinal AVM also can burst and cause bleeding in the spinal cord. Sometimes, the AVM gets bigger as blood flow increases. The AVM can press on the spinal cord and cause weakness or other symptoms. […] The cause of spinal arteriovenous malformations (AVMs) isn’t known. Most spinal AVMs are present at birth, known as congenital. But others may happen later in life.

• #39 Arteriovenous Malformations of the Central Nervous System | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/17848

  Though the exact mechanism of AVM formation is not fully understood, they are believed to form secondary to an abnormal arrest during embryologic vascular development. […] Multiple genetic mutations have been noted in patients with sporadic AVMs, including somatic activating KRAS mutations, the stop-gain mutation in SMAD9, and an increase in Notch-3 receptor expression. […] Increased KRAS activity leads to increased MAPK/ERK pathway activity with downstream elevations in Notch signaling and angiogenesis factors. […] A significantly lower level of SMAD9 in AVM vessels was observed, as well as a decrease in SMAD4 phosphorylation. […] In 2015, Hill-Fellberg et al discovered a significant increase in Notch-3 receptor expression in AVM vasculature compared to brain samples without AVM. […] Arteriovenous malformations are abnormal arterial to venous structural connections without capillaries or intervening cortical tissue. AVMs demonstrate nonphysiological hemodynamics, which affects the structure of the vessels within; they are typically high-flow, low-resistance shunts. Elevated hydrostatic pressure is a postulated contributing risk to hemorrhage. […] Spinal AVMs may rupture due to vascular instability. Arterialized venous architecture leads to vascular hypertension, which then exerts a mass effect on surrounding neural tissues and ischemic injury, leading to progressive myelopathy, paresthesias, motor deficits, or bowel or bladder dysfunction.

• #40 Spinal vascular malformations | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/spinal-vascular-malformations?lang=us

  Spinal vascular malformations are a rare but important group of lesions that range widely in size, flow, and pathophysiology. Some, if undiagnosed and untreated, can lead to serious complications. […] It is worth separating lesions without arteriovenous shunting (i.e. cavernous malformations) from those that do have shunting (i.e. AVM and AVF). Notably, much of the older literature described all arteriovenous shunting lesions as arteriovenous malformations (AVM), but newer classifications have distinguished arteriovenous malformations from arteriovenous fistulas (AVF). […] Spinal arteriovenous shunts („malformations”) have classically been categorized in a numbered system and broadly speaking these have remained similar, although over time the names for each have changed and additional categories and subcategories have been proposed.

• #41 Spinal vascular malformations | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/spinal-vascular-malformations?lang=us

  The main types are as follows: dural arteriovenous fistulae (DAVF; 70% of all spinal arteriovenous shunts), arteriovenous malformations (AVM), and cavernous malformation. […] Krings et al. noted that spinal vascular malformations can be distinguished by their vascular anatomy into dural and pial arteriovenous shunting lesions and cavernous malformations, analogous to brain vascular malformations.

• #42 Spinal arteriovenous malformations

  https://www.scielo.org.mx/article_plus.php?pid=S1665-50442021000200077&tlng=en&lng=es

  sAVMs represent an abnormal, often tiny, arteriovenous shunt located within the dura of the spinal cord. […] Blood flow through the fistula runs through a radicular vein in a retrograde manner to the coronal and pial venous plexus, which becomes dilated and tortuous. Outflow impairment to the epidural drainage system or blockage of venous return in the cava system explains this venous dilatation. […] Venous congestion is now recognized as a primary source of neurologic disability with sAVMs. Recent studies have validated the elevated pressure in the draining vein as a causative agent in myelopathy, and shown pathologic correlates, including hyalinized small blood vessels, perivascular/intraparenchymal lymphocytic infiltration, glial cell proliferation, and neuronal degeneration. […] Although impairment of venous drainage from the spinal cord parenchyma is most significant at the level of the shunt, the spread of venous hypertension in the cranial and caudal directions causes damage to the cord over a long distance. […] Hemorrhage can also precipitate neurologic decline: 25% of sAVMs patients will present with a ruptured lesion, as evidenced by subarachnoid hemorrhage (SAH), intraparenchymal hemorrhage, or a combination.

• #43 Spinal arteriovenous malformations

  https://www.scielo.org.mx/article_plus.php?pid=S1665-50442021000200077&tlng=en&lng=es

  sAVMs represent an abnormal, often tiny, arteriovenous shunt located within the dura of the spinal cord. […] Blood flow through the fistula runs through a radicular vein in a retrograde manner to the coronal and pial venous plexus, which becomes dilated and tortuous. Outflow impairment to the epidural drainage system or blockage of venous return in the cava system explains this venous dilatation. […] Venous congestion is now recognized as a primary source of neurologic disability with sAVMs. Recent studies have validated the elevated pressure in the draining vein as a causative agent in myelopathy, and shown pathologic correlates, including hyalinized small blood vessels, perivascular/intraparenchymal lymphocytic infiltration, glial cell proliferation, and neuronal degeneration. […] Although impairment of venous drainage from the spinal cord parenchyma is most significant at the level of the shunt, the spread of venous hypertension in the cranial and caudal directions causes damage to the cord over a long distance. […] Hemorrhage can also precipitate neurologic decline: 25% of sAVMs patients will present with a ruptured lesion, as evidenced by subarachnoid hemorrhage (SAH), intraparenchymal hemorrhage, or a combination.

• #44 Spinal arteriovenous malformations

  https://www.scielo.org.mx/article_plus.php?pid=S1665-50442021000200077&tlng=en&lng=es

  sAVMs represent an abnormal, often tiny, arteriovenous shunt located within the dura of the spinal cord. […] Blood flow through the fistula runs through a radicular vein in a retrograde manner to the coronal and pial venous plexus, which becomes dilated and tortuous. Outflow impairment to the epidural drainage system or blockage of venous return in the cava system explains this venous dilatation. […] Venous congestion is now recognized as a primary source of neurologic disability with sAVMs. Recent studies have validated the elevated pressure in the draining vein as a causative agent in myelopathy, and shown pathologic correlates, including hyalinized small blood vessels, perivascular/intraparenchymal lymphocytic infiltration, glial cell proliferation, and neuronal degeneration. […] Although impairment of venous drainage from the spinal cord parenchyma is most significant at the level of the shunt, the spread of venous hypertension in the cranial and caudal directions causes damage to the cord over a long distance. […] Hemorrhage can also precipitate neurologic decline: 25% of sAVMs patients will present with a ruptured lesion, as evidenced by subarachnoid hemorrhage (SAH), intraparenchymal hemorrhage, or a combination.

• #45 Spinal arteriovenous malformation in a pediatric patient with a history of congenital syphilis: a case report | BMC Pediatrics | Full Text

  https://bmcpediatr.biomedcentral.com/articles/10.1186/s12887-021-02707-y

  Spinal arteriovenous malformations in children are extremely rare and pose great risk for intraoperative hemorrhage. […] Spinal AVMs are categorized as types I-IV that differ by where and when they present. Type I forms spontaneously in the dura during adulthood, while type II forms within the spinal cord itself. Type III forms during development in utero, and type IV forms in the pia mater of the spinal cord. […] Since hemorrhage is the most common intraoperative complication, from the anesthesia standpoint, preparation for massive transfusion is imperative prior to and during surgery. […] Congenital syphilis may present with vascular changes that might impact surgical approaches and treatment outcomes in patients with spinal arteriovenous malformations. […] One of the first documented cases of paraplegia secondary to syphilis showed inflammation of the meninges and thickened and occluded vessels surrounding the spinal cord.

• #46 Arteriovenous Malformations and Fistulas (AVM/AVF) of the Spinal Cord: Practice Essentials, Background, History of the Procedure

  https://emedicine.medscape.com/article/248456-overview

  Spinal malformations can be separated into 2 subgroups: AVMs and AVFs. Spinal arteriovenous malformations (AVMs) are a rare form of spinal blood vessel defect that results in vessel engorgement leading to clinical signs secondary to mass effect and ischemia. These lesions represent an abnormal connection between the spinal radicular artery and the medullary vein of the spinal cord. This type of fistula creates a slow-flow vascular malformation that typically develops over months to years. High-pressure arterial flow from the radicular artery dilates the perimedullary venous system, causing venous stasis and hypertension. Venous hypertension results in a decreased arteriovenous gradient. The end result consists of venous outflow obstruction, hypoperfusion, and hypoxia of the spinal cord. Neurologic compromise is thought to occur secondary to this venous engorgement and resultant spinal cord ischemia. […]

• #47 Spinal arteriovenous malformation in a pediatric patient with a history of congenital syphilis: a case report | BMC Pediatrics | Full Text

  https://bmcpediatr.biomedcentral.com/articles/10.1186/s12887-021-02707-y

  Spinal arteriovenous malformations in children are extremely rare and pose great risk for intraoperative hemorrhage. […] Spinal AVMs are categorized as types I-IV that differ by where and when they present. Type I forms spontaneously in the dura during adulthood, while type II forms within the spinal cord itself. Type III forms during development in utero, and type IV forms in the pia mater of the spinal cord. […] Since hemorrhage is the most common intraoperative complication, from the anesthesia standpoint, preparation for massive transfusion is imperative prior to and during surgery. […] Congenital syphilis may present with vascular changes that might impact surgical approaches and treatment outcomes in patients with spinal arteriovenous malformations. […] One of the first documented cases of paraplegia secondary to syphilis showed inflammation of the meninges and thickened and occluded vessels surrounding the spinal cord.

• #48

  https://journals.lww.com/jcvs/fulltext/2022/10010/syndromic_association_of_spinal_arteriovenous.10.aspx

  Spinal cord arteriovenous malformations (SCAVMs) are abnormally developed blood vessels can arise from any vascular components which result in clinical signs and symptoms secondary to mass effect and ischemia. […] Pathophysiology involves increase in venous pressure due to shunting of blood (steal phenomenon) causing congestion in medullary veins and reduced intramedullary blood flow resulting in ischemic hypoxic insult to the spinal cord. […] The aetiology of overgrowth syndromes associated with vascular anomalies, including CLOVES, is largely unknown. […] Type III (Juvenile/Metameric) AVM is lesions most difficult to treat, with high flow and large malformations involving paraspinal structures as well. Neurological deficits are secondary to venous congestion, haemorrhage, spinal cord compression or vascular steal. The treatment of such lesions is mainly palliative in goal of stabilising the nidal size and symptoms. […] Staged endovascular partial treatment of these malformations may serve to reduce the size and alleviate congestive symptoms.

• #49 A Rare Case of Cervical Spinal Arteriovenous Malformation: A Case Report

  https://www.mdpi.com/1648-9144/60/6/1011

  Arteriovenous malformation (AVM) is an abnormal connection of vasculature resulting in capillary bed bypassing and leading to neurological deterioration and high risk of bleeding. […] Spinal arteriovenous malformations (AVMs) are developmental or acquired abnormal direct connections of normal-sized to enlarged radiculomedullary arteries with enlarged tortuous radiculomedullary veins, without an intervening capillary network. […] One mutated gene (MAP2K1), which causes hereditary hemorrhagic telangiectasia (HHT), has been identified to be responsible for inherited forms of extracranial arteriovenous malformation. […] Intramedullary spinal AVMs are supplied by medullary arteries (anterior and posterior spinal artery), drain through medullary veins, and are characterized by high pressure, relatively low resistance, and high blood flow. Ultimately this leads to venous hypertension, which, in turn, can precipitate many neurological deficits secondary to mass effect and normal spinal blood flow disruption.

• #50 A Rare Case of Cervical Spinal Arteriovenous Malformation: A Case Report

  https://www.mdpi.com/1648-9144/60/6/1011

  Arteriovenous malformation (AVM) is an abnormal connection of vasculature resulting in capillary bed bypassing and leading to neurological deterioration and high risk of bleeding. […] Spinal arteriovenous malformations (AVMs) are developmental or acquired abnormal direct connections of normal-sized to enlarged radiculomedullary arteries with enlarged tortuous radiculomedullary veins, without an intervening capillary network. […] One mutated gene (MAP2K1), which causes hereditary hemorrhagic telangiectasia (HHT), has been identified to be responsible for inherited forms of extracranial arteriovenous malformation. […] Intramedullary spinal AVMs are supplied by medullary arteries (anterior and posterior spinal artery), drain through medullary veins, and are characterized by high pressure, relatively low resistance, and high blood flow. Ultimately this leads to venous hypertension, which, in turn, can precipitate many neurological deficits secondary to mass effect and normal spinal blood flow disruption.

• #51 Spinal arteriovenous malformation in a pediatric patient with a history of congenital syphilis: a case report | BMC Pediatrics | Full Text

  https://bmcpediatr.biomedcentral.com/articles/10.1186/s12887-021-02707-y

  Spinal arteriovenous malformations in children are extremely rare and pose great risk for intraoperative hemorrhage. […] Spinal AVMs are categorized as types I-IV that differ by where and when they present. Type I forms spontaneously in the dura during adulthood, while type II forms within the spinal cord itself. Type III forms during development in utero, and type IV forms in the pia mater of the spinal cord. […] Since hemorrhage is the most common intraoperative complication, from the anesthesia standpoint, preparation for massive transfusion is imperative prior to and during surgery. […] Congenital syphilis may present with vascular changes that might impact surgical approaches and treatment outcomes in patients with spinal arteriovenous malformations. […] One of the first documented cases of paraplegia secondary to syphilis showed inflammation of the meninges and thickened and occluded vessels surrounding the spinal cord.

• #52 Spinal Arteriovenous Malformations | Neupsy Key

  https://neupsykey.com/spinal-arteriovenous-malformations-2/

  Spinal vascular malformations form a diverse group of vascular entities, with disparate etiologies as well as presentation. […] The exact etiology of these AVMs is unknown; they are believed to be acquired lesions that may occur either spontaneously or following trauma. […] Type IV AVMs (also called perimedullary fistulas) appear to be acquired lesions that are most commonly located in the thoracolumbar region, occasionally are isolated to the thoracic levels, and rarely occur in the cervical region. […] These AVMs consist of a direct fistulous connection between the anterior or (less commonly) the posterior spinal artery and a spinal vein. […] As a result of the fistula, there may be massive aneurysmal venous dilatation, which may extend to the craniocervical junction and even into the posterior cranial fossa.

• #53 Spinal Arteriovenous Malformations | Neupsy Key

  https://neupsykey.com/spinal-arteriovenous-malformations-2/

  Spinal vascular malformations form a diverse group of vascular entities, with disparate etiologies as well as presentation. […] The exact etiology of these AVMs is unknown; they are believed to be acquired lesions that may occur either spontaneously or following trauma. […] Type IV AVMs (also called perimedullary fistulas) appear to be acquired lesions that are most commonly located in the thoracolumbar region, occasionally are isolated to the thoracic levels, and rarely occur in the cervical region. […] These AVMs consist of a direct fistulous connection between the anterior or (less commonly) the posterior spinal artery and a spinal vein. […] As a result of the fistula, there may be massive aneurysmal venous dilatation, which may extend to the craniocervical junction and even into the posterior cranial fossa.

• #54 Spinal Arteriovenous Malformations | Neupsy Key

  https://neupsykey.com/spinal-arteriovenous-malformations-2/

  Spinal vascular malformations form a diverse group of vascular entities, with disparate etiologies as well as presentation. […] The exact etiology of these AVMs is unknown; they are believed to be acquired lesions that may occur either spontaneously or following trauma. […] Type IV AVMs (also called perimedullary fistulas) appear to be acquired lesions that are most commonly located in the thoracolumbar region, occasionally are isolated to the thoracic levels, and rarely occur in the cervical region. […] These AVMs consist of a direct fistulous connection between the anterior or (less commonly) the posterior spinal artery and a spinal vein. […] As a result of the fistula, there may be massive aneurysmal venous dilatation, which may extend to the craniocervical junction and even into the posterior cranial fossa.

• #55 Pathophysiology of Type I Spinal Dural Arteriovenous Malformations – Barrow Neurological Institute

  https://www.barrowneuro.org/for-physicians-researchers/education/grand-rounds-publications-media/barrow-quarterly/volume-12-no-2-1996/pathophysiology-of-type-i-spinal-dural-arteriovenous-malformations/

  Classification of spinal arteriovenous malformations (AVMs) into distinct groups is based on angiographic criteria, but few histological data support the most popular nomenclature. […] Questions exist regarding the pathogenesis and precise fistula location in spinal dural AVMs. […] Despite recent advances in understanding Type I and Type IV spinal AVMs, questions remain concerning the location of the fistula, their pathogenesis and natural history, and the cause of neurological symptoms. […] Furthermore, intraoperative pressure measurements from the overall series of 12 patients provide further information about the pathogenesis of the AV fistula and the mechanisms that might produce venous hypertension and neurological symptoms.

• #56 Spinal Arteriovenous Malformations | SpringerLink

  https://link.springer.com/chapter/10.1007/978-981-10-8950-3_28

  Clinical signs and symptoms of spinal arteriovenous malformation (AVM) have different characteristics according to the type of the AVM. […] The pathogenesis is believed to be the ruptured of the nidus that caused subarachnoid hemorrhage or even intramedullary hemorrhage. […] In the clinical presentation, motor weakness is the most common symptom, followed by paresthesia and sphincter disturbances. […] Pain and acute onset of myelopathy are relatively seldom for this spinal AV malformation type. […] In a low-flow fistula or malformation, the symptoms can develop slowly and give a similar pathogenesis and clinical characteristic to the dural type.

• #57 Spinal Arteriovenous Malformations | SpringerLink

  https://link.springer.com/chapter/10.1007/978-981-10-8950-3_28

  Clinical signs and symptoms of spinal arteriovenous malformation (AVM) have different characteristics according to the type of the AVM. […] The pathogenesis is believed to be the ruptured of the nidus that caused subarachnoid hemorrhage or even intramedullary hemorrhage. […] In the clinical presentation, motor weakness is the most common symptom, followed by paresthesia and sphincter disturbances. […] Pain and acute onset of myelopathy are relatively seldom for this spinal AV malformation type. […] In a low-flow fistula or malformation, the symptoms can develop slowly and give a similar pathogenesis and clinical characteristic to the dural type.

• #58 Spinal Vascular Malformations and Treatment | SpringerLink

  https://link.springer.com/10.1007/978-1-4614-9212-2_45-1?fromPaywallRec=true

  Spinal vascular malformations are rare, but a diverse group of neurovascular pathologies including arteriovenous malformations (AVMs), cavernous malformations, and dural arteriovenous fistulas (dAVFs) that occur due to developmental derangement of the vascular system. […] Pathophysiologic mechanisms leading to clinical symptoms include intramedullary or subarachnoid hemorrhages, arterial ischemia, progressive venous congestion resulting in progressive myelopathy, space-occupying nature of the malformation and its venous drainage, and circulatory steal phenomenon. […] Venous congestion is a major cause of neurological deterioration in spinal arteriovenous malformations.

• #59 Spinal Vascular Malformations and Treatment | SpringerLink

  https://link.springer.com/10.1007/978-1-4614-9212-2_45-1?fromPaywallRec=true

  Spinal vascular malformations are rare, but a diverse group of neurovascular pathologies including arteriovenous malformations (AVMs), cavernous malformations, and dural arteriovenous fistulas (dAVFs) that occur due to developmental derangement of the vascular system. […] Pathophysiologic mechanisms leading to clinical symptoms include intramedullary or subarachnoid hemorrhages, arterial ischemia, progressive venous congestion resulting in progressive myelopathy, space-occupying nature of the malformation and its venous drainage, and circulatory steal phenomenon. […] Venous congestion is a major cause of neurological deterioration in spinal arteriovenous malformations.

• #60 Spinal Vascular Malformations and Treatment | SpringerLink

  https://link.springer.com/10.1007/978-1-4614-9212-2_45-1?fromPaywallRec=true

  Spinal vascular malformations are rare, but a diverse group of neurovascular pathologies including arteriovenous malformations (AVMs), cavernous malformations, and dural arteriovenous fistulas (dAVFs) that occur due to developmental derangement of the vascular system. […] Pathophysiologic mechanisms leading to clinical symptoms include intramedullary or subarachnoid hemorrhages, arterial ischemia, progressive venous congestion resulting in progressive myelopathy, space-occupying nature of the malformation and its venous drainage, and circulatory steal phenomenon. […] Venous congestion is a major cause of neurological deterioration in spinal arteriovenous malformations.

• #61 Spinal Arteriovenous Malformations | SpringerLink

  https://link.springer.com/chapter/10.1007/978-981-10-8950-3_28

  Clinical signs and symptoms of spinal arteriovenous malformation (AVM) have different characteristics according to the type of the AVM. […] The pathogenesis is believed to be the ruptured of the nidus that caused subarachnoid hemorrhage or even intramedullary hemorrhage. […] In the clinical presentation, motor weakness is the most common symptom, followed by paresthesia and sphincter disturbances. […] Pain and acute onset of myelopathy are relatively seldom for this spinal AV malformation type. […] In a low-flow fistula or malformation, the symptoms can develop slowly and give a similar pathogenesis and clinical characteristic to the dural type.

• #62 Spinal Arteriovenous Malformations | SpringerLink

  https://link.springer.com/chapter/10.1007/978-981-10-8950-3_28

  Clinical signs and symptoms of spinal arteriovenous malformation (AVM) have different characteristics according to the type of the AVM. […] The pathogenesis is believed to be the ruptured of the nidus that caused subarachnoid hemorrhage or even intramedullary hemorrhage. […] In the clinical presentation, motor weakness is the most common symptom, followed by paresthesia and sphincter disturbances. […] Pain and acute onset of myelopathy are relatively seldom for this spinal AV malformation type. […] In a low-flow fistula or malformation, the symptoms can develop slowly and give a similar pathogenesis and clinical characteristic to the dural type.

• #63 Spinal Arteriovenous Malformations | SpringerLink

  https://link.springer.com/chapter/10.1007/978-981-10-8950-3_28

  Clinical signs and symptoms of spinal arteriovenous malformation (AVM) have different characteristics according to the type of the AVM. […] The pathogenesis is believed to be the ruptured of the nidus that caused subarachnoid hemorrhage or even intramedullary hemorrhage. […] In the clinical presentation, motor weakness is the most common symptom, followed by paresthesia and sphincter disturbances. […] Pain and acute onset of myelopathy are relatively seldom for this spinal AV malformation type. […] In a low-flow fistula or malformation, the symptoms can develop slowly and give a similar pathogenesis and clinical characteristic to the dural type.

• #64 Spinal arteriovenous malformation (AVM) – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/spinal-arteriovenous-malformation/symptoms-causes/syc-20355613

  Without treatment, a spinal arteriovenous malformation (AVM) can cause disability that gets worse over time. This is from damage to the spinal cord and surrounding tissues. This can cause: […] High blood pressure in the veins, known as venous hypertension. This can cause fluid to build up, called edema. It also can cause tissues to die due to lack of oxygen, known as spinal cord infarction. […] Hemorrhage, which can speed up spinal cord damage.

• #65 Spinal arteriovenous malformation (AVM) – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/spinal-arteriovenous-malformation/symptoms-causes/syc-20355613

  Without treatment, a spinal arteriovenous malformation (AVM) can cause disability that gets worse over time. This is from damage to the spinal cord and surrounding tissues. This can cause: […] High blood pressure in the veins, known as venous hypertension. This can cause fluid to build up, called edema. It also can cause tissues to die due to lack of oxygen, known as spinal cord infarction. […] Hemorrhage, which can speed up spinal cord damage.

• #66 Spinal arteriovenous malformation (AVM) – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/spinal-arteriovenous-malformation/symptoms-causes/syc-20355613

  Without treatment, a spinal arteriovenous malformation (AVM) can cause disability that gets worse over time. This is from damage to the spinal cord and surrounding tissues. This can cause: […] High blood pressure in the veins, known as venous hypertension. This can cause fluid to build up, called edema. It also can cause tissues to die due to lack of oxygen, known as spinal cord infarction. […] Hemorrhage, which can speed up spinal cord damage.

• #67 Spinal arteriovenous malformation in a pediatric patient with a history of congenital syphilis: a case report | BMC Pediatrics | Full Text

  https://bmcpediatr.biomedcentral.com/articles/10.1186/s12887-021-02707-y

  It is unclear if our patient developed vascular symptoms due to hematogenous spread of Treponema pallidum or if it was due to a congenital defect. […] In our opinion, our patient’s congenital syphilis was coincidental and unrelated to the spinal AVM. […] The decision was made to postpone surgical intervention in preparation for perioperative hemorrhage. […] Anesthetic management for spinal AVMs includes preparation for the hemodynamic changes that may occur perioperatively due to hemorrhage. […] Embolization is the preferred method to treat spinal AVMs. […] Loss of blood flow to the spinal cord should be monitored by measuring spinal cord potentials. […] Paraplegia is a common symptom among patients with spinal AVMs. […] Our goal of anesthetic management remained as prevention of hemorrhagic complications during resection of the AVM while also preserving the spinal cord. […] This report highlights the importance of preparing for massive transfusion and intraoperative monitoring prior to surgical resection of spinal AVMs in the pediatric population.

• #68 Paravertebral Arteriovenous Malformations with Epidural Drainage: Clinical Spectrum, Imaging Features, and Results of Treatment | American Journal of Neuroradiology

  https://www.ajnr.org/content/20/5/749

  Arteriovenous malformations (AVMs) of the spine or spinal cord can be characterized as spinal cord AVMs, spinal cord and dural arteriovenous fistulas, and AVMs occurring outside the dura but draining into the epidural veins. […] A clear understanding of the anatomy and pathophysiology is necessary to plan treatment. […] PVAVMs are rare lesions that have diverse presentations and imaging features. It is important to understand the pathophysiology of these lesions to plan appropriate treatment. […] A PVAVM can produce venous congestive myelopathy similar to that of a dural AVFs or compressive myelopathy as a result of enlarged epidural veins. […] We hypothesize that in patients with reflux into the radicular veins, anatomically, the radicular veins were draining into the epidural venous plexus whereas in the other patients, even though the epidural veins were grossly dilated, venous hypertension of the cord was not produced because the radicular veins were draining by an alternative route that was not interconnected with the epidural veins.

• #69 Paravertebral Arteriovenous Malformations with Epidural Drainage: Clinical Spectrum, Imaging Features, and Results of Treatment | American Journal of Neuroradiology

  https://www.ajnr.org/content/20/5/749

  The treatment of a symptomatic high-flow PVAVM with multiple feeders remains a challenge. Such a lesion often extends over multiple spinal levels and does not have a well-defined nidus. […] Treatment of PVAVMs, whether surgical or endovascular, requires a clear understanding of their pathophysiology and anatomy and is directed toward elimination of the venous expression of the disease, which is usually responsible for the clinical symptoms.

• #70 A Rare Case of Cervical Spinal Arteriovenous Malformation: A Case Report

  https://www.mdpi.com/1648-9144/60/6/1011

  Treatment is complex and largely dependent on the angioarchitecture of the AVMs, as well as prior treatment approaches and its success rate of reversing AVMs neurological morbidity. Usually, the treatment of AVMs is conducted via endovascular embolization and/or surgery. […] Endovascular embolization and surgery success rate of complete obliteration of AVMs vary depending on the type. In intramedullary AVMs, complete obliteration is seen in about 33 to 38% and recanalization of AVMs is a common problem requiring repeated embolization and/or surgery. […] It is difficult to determine the superior treatment modality, but the current approach is to combine endovascular embolization prior to neurosurgery with complete or partial resection for better neurological outcome and obliteration rate.

• #71 A Rare Case of Cervical Spinal Arteriovenous Malformation: A Case Report

  https://www.mdpi.com/1648-9144/60/6/1011

  Treatment is complex and largely dependent on the angioarchitecture of the AVMs, as well as prior treatment approaches and its success rate of reversing AVMs neurological morbidity. Usually, the treatment of AVMs is conducted via endovascular embolization and/or surgery. […] Endovascular embolization and surgery success rate of complete obliteration of AVMs vary depending on the type. In intramedullary AVMs, complete obliteration is seen in about 33 to 38% and recanalization of AVMs is a common problem requiring repeated embolization and/or surgery. […] It is difficult to determine the superior treatment modality, but the current approach is to combine endovascular embolization prior to neurosurgery with complete or partial resection for better neurological outcome and obliteration rate.

• #72 A Rare Case of Cervical Spinal Arteriovenous Malformation: A Case Report

  https://www.mdpi.com/1648-9144/60/6/1011

  Treatment is complex and largely dependent on the angioarchitecture of the AVMs, as well as prior treatment approaches and its success rate of reversing AVMs neurological morbidity. Usually, the treatment of AVMs is conducted via endovascular embolization and/or surgery. […] Endovascular embolization and surgery success rate of complete obliteration of AVMs vary depending on the type. In intramedullary AVMs, complete obliteration is seen in about 33 to 38% and recanalization of AVMs is a common problem requiring repeated embolization and/or surgery. […] It is difficult to determine the superior treatment modality, but the current approach is to combine endovascular embolization prior to neurosurgery with complete or partial resection for better neurological outcome and obliteration rate.

• #73 Arteriovenous Malformations—Current Understanding of the Pathogenesis with Implications for Treatment

  https://www.mdpi.com/1422-0067/22/16/9037

  To develop novel effective therapeutic strategies for AVM treatment, a better understanding of the pathogenesis of AVM formation is paramount. […] A three-event hypothesis suggesting concurrence of two additional, regionally confined triggers, is mainly based on insights gained from animal studies. […] These studies suggested that a combination of a loss of one functional allele in an HHT-locus, a local loss of protein, and an angiogenic stimulus directed towards ECs might be required for AVM development in mice. […] Furthermore, determinants such as blood flow and shear stress have been identified to be contributory to AVM formation. […] Further research will be required to strengthen our understanding of AVM formation, and translate these insights from animal models to humans.

Zobacz więcej