Functional Vascular Anatomy and Arteriovenous Shunts of the Spine.

The history of vascular anatomy of the spinal cord and spine began in the late 19th century. With recent advances in endovascular and surgical treatment of vascular lesions of the spinal cord, understanding the vascular anatomy of the spinal cord has become more important than ever. Catheter angiography is the gold standard for diagnosing vascular lesions of the spinal cord, and the vascular architecture of the spinal cord itself is relatively simple, a repetition of basic longitudinal and axial structures. This review discusses the vascular anatomy of the spine and spinal cord from the embryological point of view, as well as an overview of typical spinal arteriovenous shunt diseases mainly depending on their locations: paraspinal, epidural, dural, perimedullary, intramedullary, filum terminale/cauda equina, craniocervical junction, and related diseases.

Acute Spinal Hemorrhage from a Cauda Equina Arteriovenous Fistula Fed by the Proximal Radicular Artery.

Spinal cauda equina arteriovenous fistulas (CEAVFs) and spinal hemorrhage from spinal AVF are relatively unusual. To our knowledge, such a case of CEAVF presenting with hemorrhage has not been reported. Here, we describe such a rare case of CEAVF. Spinal magnetic resonance imaging and angiography revealed a CEAVF at the L2 level, fed by the proximal radicular artery and with 2 associated venous varices. Considering the feeder from the proximal radicular artery and the presence of acute hemorrhage, direct surgery was performed. Intraoperatively, spinal hematoma and the fistula were identified at the L2 level. The fistula was clipped and divided successfully. The postoperative course was uneventful. CEAVF presenting with spinal hemorrhage is extremely rare. This case demonstrated the angioarchitecture features of CEAVF. The clinicians should be aware of the possibility of this condition and the importance of treatment selection.

Cauda Equina Arteriovenous Malformation with Bilateral Arterial Feeders.

Cauda equina arteriovenous malformation (AVM) is extremely rare. To our knowledge, only 2 cases have been reported previously and are supplied by a unilateral lateral sacral artery (LSA). Here, we report a rare cauda equina AVM at the level of L5-S1, which is supplied by the bilateral LSAs. Given the multiple feeders and complex angioarchitecture, endovascular embolization was performed with Onyx (ev3) successfully. The postoperative course of the patient was uneventful, and symptoms gradually improved. The present case demonstrated the angioarchitecture of the bilateral arterial supplies and venous drainage of the cauda equina AVMs. Cauda equina AVM with bilateral arterial feeders is extremely rare. However, clinicians should be aware of the possibility of this condition and the importance of selective spinal angiography of bilateral LSAs.

Central Nervous System Bleeding After a Lumbar Puncture: Still an Ongoing Complication.

BACKGROUND A lumbar puncture is a procedure performed to uncover the state of the central nervous system by analysis of the cerebrospinal fluid. It is done also to infuse medications in the subdural space. A lumbar puncture should not cause central nervous system bleeding, but this complication is still occurring in certain cases. CASE REPORT We present 2 cases where a lumbar puncture was performed in the emergency department. The first patient had severe inflammatory lower back pain and received epidural steroids through a lumbar puncture and the second case presented with the clinical picture of meningitis and a lumbar puncture was performed for diagnostic purposes. In both cases, major complications arose secondary to bleeding in the cerebrospinal fluid. The first case developed a bleeding tendency because the patient had acute renal failure and was on low molecular weight heparin. The second case had low platelet count because of myelodysplasia. Both cases bled into the subarachnoid space and subdural space resulting in compression of the cauda equine and paralysis. The bleeding eventually flowed into the posterior fossa resulting in vasospasm of the posterior circulation and infarction of the posterior cerebral arteries. CONCLUSIONS We concluded that both patients sustained complications from the lumbar puncture because of a bleeding tendency secondary to systemic illnesses and multiple drugs and their side effects. We recommend that patients' medical condition be well evaluated, and proper blood studies be performed prior to lumbar punctures to avoid major morbidities.

Combined Spinal Arteriovenous Malformation and Spinal Dysraphism.

BACKGROUND: Spinal vascular malformations as a group are rare, and coexistence of a spinal arteriovenous malformation (AVM) in or around the spinal dysraphism is extremely rare. We report 2 cases of combined spinal dysraphism and vascular malformations of the spinal cord. CASE DESCRIPTION: The first case was an AVM located in a filum terminale lipoma fed by the artery of the filum terminale. This case was managed by multiple endovascular embolizations followed by surgery. The second case was an AVM located in a lumbar lipomyelocele managed by endovascular embolization. These cases illustrate the imaging findings of a rare entity and present the diagnostic and therapeutic challenges. CONCLUSIONS: Endovascular embolization combined with surgical resection is the most commonly used treatment for spinal dysraphism with spinal cord AVM. Careful analysis of spinal angiography is necessary owing to the distorted vascular and surgical anatomy of the region affected by spinal dysraphism.

A case of arteriovenous fistula of the cauda equina fed by the proximal radicular artery: anatomical features and treatment precautions.

PURPOSE: Arteriovenous fistula (AVF) of the cauda equina (CE) fed by the proximal radicular artery (PRA) is very rare, and the differentiation from that of the filum terminale (FT) is important to avoid treatment-related injury to the CE when endovascular treatment is selected. The authors describe a case of AVF of the CE fed by the PRA, demonstrate the anatomical features and discuss the treatment precautions. METHODS: A 69-year-old man presented with a transient weakness of lower limbs. Spinal angiography and magnetic resonance (MR) imaging revealed AVF, of which the feeding artery arose from the anterior spinal artery (ASA), forming the fistula at L2 level to be drained into the longitudinal venous trunk. Under a tentative diagnosis of AVF of the FT, endovascular treatment was attempted but failed due to impossible catheterization into the ASA. Therefore, surgery was performed. RESULTS: Intraoperative finding revealed that the feeding artery and draining vein were not on the FT but on the CE, resulting in the proper diagnosis of AVF of the CE. Surgical clips were applied to the draining vein closest to the fistula, and postoperatively the symptom improved gradually. Although we thoroughly reevaluated spinal angiography and MR images postoperatively, AVF of the CE fed by the PRA and that of the FT were not distinguishable. CONCLUSIONS: The authors described a case of AVF of the CE fed by the PRA and demonstrated the difficulty of the differentiation from that of the FT. The utmost precautions are necessary when endovascular treatment is selected.

Vascular Anatomy of the Cauda Equina and Its Implication on the Vascular Lesions in the Caudal Spinal Structure.

The cauda equina is composed of the lumbosacral and the coccygeal nerve roots and the filum terminale. In the embryonic period, discrepancy in development between the termination of the spinal cord and the spinal column results in elongation of the nerve roots as well as the filum terminale in this region. Although the vascular anatomy of the caudal spinal structure shares many common features with the other metameric levels, this elongation forms the basis of the characteristic vascular anatomy in this region. With the evolution of the high quality imaging techniques, vascular lesions in the cauda equina are being diagnosed more frequently than ever before. Albeit the demand for accurate knowledge of the vascular anatomy in this region, descriptions are often fragmented and not easily accessible. In this review, the author attempted to organize the existing knowledge of the vascular anatomy in the cauda equina and its implication on the vascular lesions in this region. Also reviewed is the clinically relevant embryological development of the cauda equina.

Circulatory dynamics of the cauda equina in lumbar canal stenosis using dynamic contrast-enhanced magnetic resonance imaging.

BACKGROUND CONTEXT: There has been no study regarding the cauda equina circulation of patients with neurogenic intermittent claudication (NIC) in lumbar spinal canal stenosis (LSCS) using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). PURPOSE: The mechanism responsible for the onset of NIC was investigated using DCE-MRI to examine changes in cauda equina blood flow in patients with LSCS. STUDY DESIGN: This was a retrospective longitudinal registry and magnetic resonance imaging study. PATIENT SAMPLE: The subjects consisted of 23 patients who had LSCS associated with NIC (stenosis group). Ten asymptomatic volunteers who did not have NIC served as controls (control group). In the LSCS group, the cross-sectional area of the dural sac was <75 mm2 at the site of most severe stenosis. These patients were further divided into single and double stenosis subgroups. OUTCOME MEASURES: The main measures we used were the signal intensity (S-I) ratio and the shape and size of the time intensity (T-I) curves. We compared these between the stenosis and control groups. METHODS: At first, plain T1-weighted MR images were obtained and the lumbar dural sac cross-sectional area was measured using a digitizer. For DCE-MRI, sagittal T1-weighted images of the same slice were acquired continuously for 10 minutes after administration of gadolinium as an intravenous bolus to observe the distribution of contrast medium (gadolinium) in the cauda equina. To objectively evaluate changes in contrast enhancement of the cauda equina at the site of canal stenosis, regions of interest were established. The signal intensity (SI) ratio was calculated to compare the signal intensities before and after contrast enhancement, and time-intensity curves were prepared to investigate changes over time. RESULTS: The static imaging findings and the changes of gadolinium uptake showed striking differences between the study and control patients. In the stenosis group, abnormal intrathecal enhancement showed around the site of stenosis on enhanced MR imaging. The SI ratio at the site of canal stenosis had a slower increase in the arterial phase when compared with that in the control group and remained high in the venous phase for up to 10 minutes. Finally, abnormal intrathecal enhancement was visible around the site of stenosis on enhanced MR imaging in all patients. CONCLUSIONS: These clinical data indicate that cauda equina nerve roots in the LSCS patients are pathologic even when symptoms are not elicited in the supine position, suggesting that intraradicular venous congestion and edema themselves do not influence the existence of radicular symptoms.

Pathomorphological description of the shunted portion of a filum terminale arteriovenous fistula.

BACKGROUND CONTEXT: The clinical morphology of a filum terminale arteriovenous fistula (f-AVF) is well known; however, pathological details of the fistulized portion are unknown. Herein, we report the pathological findings of the f-AVF. STUDY DESIGN: Case report and literature review. PURPOSE: To present a detailed pathological examination of the fistulized portion of the f-AVF. METHODS: A 71-year-old man presented with gradually worsening bilateral foot paresthesias and anal dysesthesia. T2-weighted magnetic resonance imaging showed flow voids surrounding an edematous conus medullaris and cauda equina with spinal stenosis at L3-L4 and L4-L5. Spinal digital subtraction angiography demonstrated an f-AVF fed by the left T9 intercostal artery. RESULTS: We performed laminotomies of L3 and L4 to open the dura mater and found a hypertrophic filum terminale. It was resected, leaving a length of 2 cm between the abnormal proximal end and normal distal end. The f-AVF completely disappeared after the surgery. On pathological examination, the filum terminale included two vessels at the proximal end and one at the distal end. At the proximal end, immunostaining showed one vessel that was definitively an artery with both an internal elastic membrane (IEM) and smooth muscle. The other was a vein and lacked an IEM. On the distal side, the collagen fibers gradually increased, the IEM partially disappeared from the arterial wall, and the vein became arterialized with a thin IEM. At the distal end the two vessels joined. Therefore, we speculated that the fistulized portion of the f-AVF was not a fistula point but had some lengths where the artery had characteristics of a vein and there was venous arterialization. CONCLUSIONS: The filum arteriovenous shunting occurred at the portion where there was venous arterialization and the artery had the characteristics of a vein. Therefore, resecting the filum terminale requires more proximal from the normal distal end.

Filum terminale arteriovenous fistulas: the role of endovascular treatment.

OBJECT: The authors describe the clinical presentation, imaging features, and management of patients presenting with filum terminale arteriovenous fistulas (FTAVFs) and the role of transarterial treatment in their management. METHODS: The authors retrospectively reviewed data obtained in 10 patients with FTAVFs diagnosed between January 1990 and December 2011. RESULTS: Most patients (70%) were male, and the age of the population ranged from 31 to 72 years (mean 58.2 years). Clinical presentation was progressive paraparesis and sensory loss in the lower extremities in 9 cases, back pain in 7, radicular pain in 3, bowel/bladder disturbance in 5, and impotence in 1. The duration of symptoms varied between 2 and 24 months. Initial MRI studies showed intramedullary increased T2 signal, swollen cord, and dilated perimedullary veins in all patients. One patient had syringomyelia, presumably caused by venous hypertension transmitted by the perimedullary venous system. Embolization was attempted in 7 patients and was curative in 6 patients. Surgery was performed in the other 4 patients in whom embolization was unsuccessful or deemed not feasible. There was no treatment-related complication in either group. Symptoms, venous congestion in the cord, and syringomyelia improved on follow-up in all patients. CONCLUSIONS: Embolization should be considered the treatment of choice for FTAVFs and can effectively treat the majority of patients presenting with an FTAVF. In a smaller group of patients in whom the angioarchitecture is unfavorable, open surgery is recommended.

Conus medullaris-cauda arteriovenous malformation and Klippel-Trenaunay syndrome: what is the treatment goal?

A 29-year-old man with Klippel-Trenaunay syndrome (KTS) presented with a symptomatic conus medullaris-cauda arteriovenous malformation (AVM) manifesting as back and right limb pain, which abruptly worsened with the onset of right limb weakness and urinary retention. He was treated by multisession endovascular embolization resulting in improved neurological status. KTS is a sporadic disease with unknown etiology, but genetic susceptibility may lead to the over-expression of angiogenic factors and increased angiogenesis. KTS may be exceptionally associated with slow-flow spinal AVM, but there is no consensus about the optimal treatment for these symptomatic lesions. Embolization treatment may represent a safe option to minimize complications and possibly improve the neurological status in patients with spinal AVM associated with KTS, if one or both legs are already impaired by hypertrophy or other vascular malformations. Genetic analysis may reveal an underlying angiogenesis change, so closer follow up might be indicated in selected patients.

Arteriovenous fistula of the filum terminale: radiological diagnosis and therapeutic management by embolization.

A 60-year-old man had progressive paraparesis, paresthesia of both lower limbs and sphincter dysfunction. He underwent MRI, which revealed perimedullar abnormal vascular channels associated with a hypersignal in the thoracolumbar cord. Because of the patient's age and symptomatology, a dural arteriovenous shunt was first suspected. MRA confirmed dilatation of the perimedullary venous channels, but also revealed an enlarged anterior spinal artery, a finding incompatible with a diagnosis of dural arteriovenous fistula. A lesion, vascularized by the anterior spinal axis and draining secondarily into the perimedullary veins, was thus suspected. Angiography diagnosed a microfistula of the filum terminale; selective distal catheterization of the arterial feeder from T11 to S1 was achieved, and the shunt closed by embolization with acrylic glue. The patient improved after endovascular treatment.

Direct surgery for spinal arteriovenous fistulas of the filum terminale with intraoperative image guidance.

STUDY DESIGN: A technical case report of direct surgery for spinal arteriovenous fistulas of the filum terminale. OBJECTIVE: We present 2 cases of spinal arteriovenous fistulas of the filum terminale directly fed by the anterior spinal artery that were successfully obliterated with intraoperative image guidance such as digital subtraction angiography, intra-arterial dye injection technique, or indocyanine green video angiography. SUMMARY OF BACKGROUND DATA: The goal of direct surgery for spinal arteriovenous fistulas is the complete obliteration of shunt vessels while preserving the normal circulation of spinal cord. Safe isolation of feeding arteries, nidus, and draining veins needs to be obtained first. Vascular flow or anatomical orientation of shunt vessels also needs to be ensured with intraoperative image guidance. METHODS: Two cases are presented. The first patient (case 1) had the lesion with a nidus formation at the L2 spinal level supplied directly by the anterior spinal artery via left L1 segmental artery. The second patient (case 2) had a lesion at the L4-L5 spinal level also supplied directly by the anterior spinal artery via the left T11 intercostal artery. Standard exposure of the lesion followed intraoperative image guidance to achieve the appropriate vascular flow or anatomical orientation of the shunt vessels. RESULTS: Complete obliteration of shunt vessels was successfully achieved without any complications in both cases. CONCLUSION: Although intraoperative image guidance is certainly not a prerequisite, the concept of safe and minimally invasive surgery makes it indispensable. It can facilitate identification of crucial or important landmarks where anatomic structures may be distorted.

Cauda equina syndrome caused by spontaneous bleeding in the filum terminale myxopapillary ependymoma: a rare pediatric case.

The majority of the filum terminale ependymomas are of the myxopapillary type, which most commonly present as lumbago or sciatic pain, an insidious clinical condition, at times accompanied by paraparesis, bladder paresis and vesical alterations. We report the case of a 13-year-old patient who presented with acute cauda equina. He underwent total resection of the lesion, which resulted in progressive improvement. The clinical conditions, diagnoses and treatments of the medullary cone and cauda equina myxopapillary ependymomas are also discussed.

Arteriovenous fistula in a nerve root of the cauda equina fed by a proximal radiculo-medullary artery: a report of two cases.

While there have been a few reports on cases of intradural spinal arteriovenous fistula located on the filum terminale, no cases of its location in a nerve root of the cauda equina have been reported to date.We describe two such cases and describe the intraoperative findings. A 40-year-old man presented weakness of his left leg. Another 62-year-old man presented paraparesis dominantly in his left leg with urinary hesitation. In both cases, spinal T2-weighted magnetic resonance images showed edema of the spinal cord, indicating a flow void around it. Digital subtraction angiography disclosed an anterior radicular artery branching from the anterior spinal artery on the surface of the conus medullaris and a turnaround vein running in the opposite direction within the cauda equina. In the first patient, while the feeding artery running along a nerve root was detected, the draining vein and the fistula were not identified at first sight. An incision into the respective nerve root exposed their location within it. In the second patient, unlike the first case, the feeding artery and the fistula were buried in a nerve root, while the draining vein was running along the nerve's surface. In both cases, permanent clips were applied to the draining vein closest to the fistula. The recognition of a hidden fistulous point in a nerve root of the cauda equina is essential for successful obliteration of the fistula.

[Conus perimedullary arteriovenous fistula with multiple shunt points including the cauda equina: a case report].

Perimedullary arteriovenous fistula (AVF) is usually located on the surface of the spinal cord and is fed by the anterior spinal artery and/or the posterior spinal artery. We report a rare case of Conus perimedullary AVF with multiple shunt points including the cauda equina. A 68-year-old man presented with leg pain when walking long distances. Magnetic resonance imaging at the thoracic and lumbar level revealed multiple signal voids with marked cord signal change. Angiography showed the perimedullary AVF fed by the anterior spinal artery from the right T9 intercostal artery at the level of the conus medullaris and the fistula fed by the left lateral sacral artery from the left internal iliac artery at the level of the cauda equina. In the first surgery, we performed surgical interruption of feeding arteries from the filum terminale and coagulated AV shunt of the conus medullaris. However residual perimedullary AVF was found at the conus medullaris in the postoperative angiography. Secondary surgery was carried out to treat residual AVF. Follow-up angiography showed complete disappearance of all AVFs. Postoperatively, the patient`s symptoms were improved. Because the Conus perimedullary AVF has the characteristics of multiple feeding arteies, multiple shunt points, and complex venous drainage, it must be kept in mind that other fistula could exist in the cauda equina or filum terminale.

Paraganglioma of the cauda equina: a highly vascular tumour.

Paragangliomas uncommonly occur in the cauda equina region. This type of tumour may be misdiagnosed pre-operatively as a neurinoma or an ependymoma. Paragangliomas are highly vascular tumours. We report three patients with paraganglioma of the cauda equina. The first patient had many dilated vessels resembling an arteriovenous malformation, which were seen during surgery. The second patient had a post-operative haemorrhage without any residual tumour. The third patient had a selective angiogram with dense tumour staining.