Posterior Spinal Artery Research Articles

Repeated Retching and Vomiting in the Pathophysiology of Isolated Spinal Aneurysms

Rupture of spinal aneurysms is a rare cause of subarachnoid hemorrhage. These aneurysms are often associated with a variety of vascular malformations that increase blood flow in the spinal circulation or with disorders that compromise the vessel wall. However, spinal aneurysms may be isolated, not associated with any known predisposing condition. The objective of this study is to explore the possible mechanisms associated with the formation and rupture of isolated spinal aneurysms (ISAs). We conducted a retrospective review of a series of consecutive patients admitted for a ruptured ISA. In all cases, spinal angiography confirmed the presence of a spinal aneurysm responsible for the bleeding. Particular attention was paid to medical history and symptoms before bleeding, for potential factors predisposing to their formation and rupture. Between 2008 and 2020, ten cases of spinal aneurysms were seen at our institution including 4 cases of ISA. All patients with ISA were female, and in 3 cases the aneurysm involved the territory of the posterior spinal artery. In 3 of these 4 (75%) ISA cases, there was a strikingly similar history of retching and vomiting preceding the thunderclap headache. In 1 patient, the aneurysm was surgically resected; pathologic analysis revealed a fusiform dissecting aneurysm. All 4 patients had a favorable outcome. We suggest that the straining during prolonged retching and vomiting plays a role in the formation and rupture of some ISAs, possibly because of pressure spikes, increased transmural arterial pressure, and increased wall shear stress during straining.

An isolated ruptured spinal aneurysm presents with a thalamic Infarct: case report

BackgroundIsolated spinal artery aneurysms are extremely rare, and their pathogenesis, clinical presentation, and treatment strategies are poorly established. We report only the second case of a patient with an isolated posterior spinal aneurysm and concurrent left thalamic infarct and review the literature to help clarify treatment strategies of isolated spinal aneurysms.Case presentationA 49-year-old patient presented with acute onset walking difficulty followed by diaphoresis, back and abdominal pain, and paraplegia. Imaging was notable for a hemorrhagic spinal lesion with compression at T12 through L4 and an acute left thalamic infarct. Surgical exploration revealed an isolated posterior spinal artery aneurysm. The aneurysm was surgically resected and the patient had partial recovery six months post-operatively.ConclusionsIsolated posterior spinal artery aneurysms of the thoracolumbar region are rare lesions that commonly present with abdominal pain, radiating back pain, and lower extremity weakness. Imaging may not provide a definitive diagnosis. The three primary treatment strategies are conservative management, endovascular treatment, or surgical resection. In patients with symptomatic cord compression, immediate surgical intervention is indicated to preserve neurologic function. In all other cases, the artery size, distal flow, morphology, and location may guide management.

Anatomical Study of the Posterior Spinal Artery Branches to the Medulla Oblongata

The posterior spinal arteries (PSAs), branches of the intracranial segment of the vertebral artery or posterior inferior cerebellar artery (PICA), run bilaterally along the spinal cord and are integral to the blood supply primarily to the posterior one-third of this structure. However, a less well-described distribution of the PSAs is their supply to the posterior medulla. The purpose of this study is to examine the medullary branches of the PSA anatomically. We conducted a cadaveric study to evaluate for branches of the PSA supplying the medulla oblongata. All 14 sides had medullary branches arising from the PSAs. The average number of branches supplying the medulla oblongata on each side was six. Most of these branches traveled laterally to anastomose with medullary branches arising from the anterior spinal artery. Additionally, lateral and ascending branches were noted. Physicians who interpret imaging of the craniocervical junction, in particular arteriograms, should be aware of ascending medullary branches arising from the anterior spinal artery. Additionally, neurosurgeons operating this region must be careful in dissecting over the posterior medulla and manipulating the cerebellar tonsils, as in telovelar approaches to the fourth ventricle, in order to avoid iatrogenic injury to these vessels. Additionally, variable stroke patterns involving the vertebral artery or PICA might include ischemia to the medulla oblongata via PSA branches and this anatomy should be kept in mind by interventionalists, radiologists, and neurologists alike.

Chapter 3 - Neurovascular anatomy: Spine

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

MORPHOLOGY AND MORPHOMETRIC ANALYSIS OF FORAMEN MAGNUM IN ADULT HUMAN SKULLS

Background: The Foramen magnum is an important landmark present at the base of the skull, it serves as a transitional zone between spine and skull. It is closely related to vital structures such as medulla oblongata, meninges, anterior and posterior spinal arteries, vertebral arteries and spinal accessory nerve, passing through it hence thorough knowledge of foramen magnum is required. These structures passing may undergo compression in case of foramen magnum herniation, meningiomas and foramen magnum achondroplasia. Aims: The present study aims in performing the morphometric analysis foramen magnum and to classify it based on its shape. Materials and methodology A total number of 64 adult dry human skulls were evaluated from the Department of Anatomy, ESIC MC & PGIMSR, Rajajinagar, Bengaluru, Karnataka. Results: The mean antero-posterior diameter was found to be 34.10 ± 2.63 mm, mean transverse diameter was 28.07 ± 1.87 mm, with mean area of 752.07 ± 111.97 mm2 and foramen magnum index was 1.21 ± 0.12. The foramen magnum shapes were classified as oval (30%), circle (12%), hexagonal (3%), pentagonal (5%), egg (17%), leaf (6%), irregular (27%). Conclusion: The morphometry along with other parameters can be used for sex determination in partially damaged skull bones of unknown individuals. The obtained data is useful not only for anatomists but also the neurosurgeons, otorhinolaryngologist and radiologists. Keywords: Foramen Magnum, Morphometry, Meningioma, Achondroplasia, Antero-Posterior Diameter, Transverse Diameter, Foramen Magnum Area, Foramen Magnum Index.

Radiculomedullary arterial contributions to the thoracolumbar spinal cord: an angiographic study.

Anterior (ASA) and posterior spinal arteries (PSA) receive vital collateral flow from radiculomedullary (RM) arteries. The purpose of this study was to review a series of spinal angiograms in order to characterize normal RM arterial anatomy. The reports of digital subtraction spinal angiograms from consecutive patients from our institution from 2002-2019 were retrospectively reviewed. The RM contributions to both the ASA and PSA were characterized by noting laterality, spinal level and multiplicity. Overall, 336 spinal angiograms from 336 patients were included. Regarding RM input to the ASA, 328 patients (97.6%) had at least one RM contribution to the ASA. Forty-six patients (46/328, 14.1%) had multiple RM ASA contributions. Three hundred and eighty-one total RM with input to the ASA were visualized. Ninety-five RM of the ASA (95/381, 24.9%) were located on the right, 286 (75.1%) on the left. Three hundred and twenty-four RM arteries (85.0%) arose between T8 and L2: 246 (64.5% overall) were located on the left, and 78 (20.5%) on the right. Sixty-one patients (18.2%) had at least one visualized RM contribution to the PSA: 16 patients (16/61, 26.2%) had more than one RM contribution to the PSA. Eighty-seven total RM contributions to the PSA were visualized. Eighty-one (93.1%) RM arose between T6 and L1, 52 of which (59.8% overall) were from the left, and 29 (33.3%) from the right. RM anastomoses with both the ASA and PSA most-commonly originate from the left-sided T6-L2 spinal levels. Multiple RM contributions to the ASA or PSA are less common.

Combined surgical and endovascular approach to treat a ventrally located perimedullary arteriovenous fistula

Perimedullary arteriovenous fistulae (PMAVFs) (also called type IV spinal cord arteriovenous malformations) are rare lesions. They are located in the subarachnoid space or just under the pia. The shunt occurs between the anterior spinal artery (ASA) and/or posterior spinal artery (PSA) and a network of perimedullary veins. The aim of the treatment, surgical or endovascular, is to occlude the fistula. This article presents a unique treatment strategy of a demanding strictly ventral PMAVF in the lower thoracic cord. A posterior surgical approach with spinal cord rotation followed by direct puncture of a distally located arterial feeder was achieved. Precise identification of the fistula with superselective contrast injections was obtained and accurate catheterization of the venous pouch with a microcatheter was performed. Complete occlusion of the PMAVF was achieved with coils.

Severe Unilateral Proprioceptive Loss in Medullary-rostral Spinal Cord Infarction. A Posterior Spinal Artery Syndrome

Introduction. The symptoms and signs found in patients with lateral medullary infarction have been described for more than 200 years. The major symptoms are vestibulo-cerebellar and dysphagia and dysphonia attributable to structures innervated by the ambiguous nucleus. Sensory symptoms and signs are often present in the ipsilateral face and contralateral limbs and trunk and sometimes the face. Case Report. A 29 year old woman had headache and left neck pain during weeks. Her left side suddenly became “completely dead and lacked feeling.” She saw double and was dizzy. Her right side remained normal. MRI showed infarction in the left lateral caudal medulla extending into the medulla-spinal junction. Vascular imaging showed a dissection of the left vertebral artery . Second case is A retired man with his neurological symptoms and signs developed in steps. He first noticed while shaving that his left face was numb, A week later, while showering, he became unsteady and had discomfort behind his left ear and in his left neck. MRI showed an infarct limited to the caudo-medial portion of the left dorsolateral medulla that extended into the rostral spinal cord. Discussion. Loss of position sense in the limbs ipsilateral to a medullary infarct has only rarely been reported. Lesions of the vertebral artery just above or below dural penetration are most likely to cause medullary infarcts that are tegmental rather than basal and to cause rostral spinal cord infarction. This region of the vertebral artery is rarely affected by atherosclerosis and the commonest lesion is dissection.

Microsurgical Resection of a Spinal Cord Pial Arteriovenous Fistula: 2-Dimensional Operative Video

We present a patient who was diagnosed 20 yr prior to current presentation with a spinal arteriovenous malformation. This patient had a 10-yr history of worsening back pain (and underwent lumbar fusion), urinary dysfunction leading to 3-yr dependence on intermittent catheterization, lower extremity paresthesias and pain, and progressive weakness with multiple falls, leading to walker then wheelchair dependence for mobility. Magnetic resonance studies showed extensive thoracic cord expansion and edema with enlarged spinal cord surface veins and flow voids extending from spinal levels T6 to the conus medullaris. Partial embolization at an outside institution elicited transient symptom improvement. Repeated spinal angiogram demonstrated persistent T10 pial arteriovenous fistula (AVF) supplied by the posterior spinal artery arising from the right T11 segmental artery as well as by the anterior spinal artery from the left T10 segmental artery. Because additional embolization carried significant risk, we planned open surgery with fistula resection. Informed consent for the surgery and video recording was obtained. The patient was placed in the prone position, and a radial artery access was obtained for intraoperative angiogram. Following a posterior T9-T11 laminectomy and dural opening, a pial dissection was performed to expose the AVF. Intraoperative indocyanine green angiography was used to assist in identifying the feeders and major drainage of the AVF. Post-AVF resection, a formal intraoperative radial access spinal angiogram demonstrated complete resection of the lesion with no residual shunt or early venous drainage. The patient improved significantly and, on last follow-up, is ambulating without any assistive devices.

ANATOMY OF THE SPINAL CORD’S BLOOD SUPPLY. Review

Relevance. The traditional scheme of blood supply to the spinal cord, formed in the 60-70s of the last century, does not correspond to the pathogenesis of many neurological disorders of the spinal cord. There is also a discrepancy in terminology: the names of arteries found in surgical and neurological works do not correspond to the names of the International Anatomical Nomenclature. Therefore, today this issue needs further analysis.
 Objective: to summarize the information of different authors on the number of spinal branches and their branches, topography, blood supply to each segment of the spinal cord, to analyze the individual variability of sources of blood supply to the spinal cord.
 Materials and methods. Analysis of scientific publications in the international electronic scientometric database PubMed by keywords for the period 2000-2018. and comparing these data with the imaginations of 1760-1993.
 Results. The idea of ​​the structural organization of the blood supply to the spinal cord has changed. With modern data, intracranial sources, namely: anterior and posterior spinal arteries, the blood supply to the true cervical spinal cord, and the rest of the department - lower cervical, thoracic, lumbar, sacral and coccygeal - blood supply from extracranial sources, and they exist in this area segmental branches of the aorta. Nowadays, extracranial sources are considered the main in the blood supply to the spinal cord. It is now known that the anterior and posterior spinal arteries are intermittent and cannot provide blood supply to the spinal cord, as previously thought. The general plan of arterial blood supply of a spinal cord can be presented in the form of a set of pools of front and back radical (radiculomedullary) arteries. The anterior radicular arteries are 4-8, and the posterior 15-20, respectively, along the spinal cord in its ventral and dorsal departments the same number of arterial pools are formed. There are anastomotic connections between these pools, which are not always functionally complete. Each of these basins is supplied by a separate radiculomedullary artery. Each such artery feeds not one but several segments of the spinal cord. The number and levels of approach to the spinal cord of radiculomedullary arteries, especially the anterior ones, differ significantly in individual variability. The perception of the vascularization of the cervical spinal cord was analyzed. At different times, information about the number of arteries that supplied blood to this department differed significantly: in 1760 it was believed that it was 31 arteries; and in 1882-1939 - only 7; in 1943 - 27, in 1958 - 6-8; in 1958 - 7-10; in 1961-1963 - 5-8; in 1966-1973 - 5; in 1993 - 1-2 arteries. Such different information about spinal cord vascularization is the result of significant individual variability.
 Conclusions. Incomplete current knowledge about the blood supply to the spinal cord is the cause of unresolved problems of etiology, pathogenesis, and clinical course of spinal ischemic strokes, including cervical localization. The existing terminological confusion regarding the names of the arteries that supply blood to the spinal cord, in particular its cervical region, is explained by the significant variability of the radiculomedullary arteries of this zone in terms of number, diameter, and location. Due to the existence of arterio-venous anastomoses, arterial myelobulbar anastomoses, adjacent areas of blood supply in this area, theft phenomena are formed and distant foci of ischemia appear, including both the spinal cord and the brain. Therefore, in order to make an angiotopic diagnosis, it is necessary to take into account not only anatomical but also physiological and pathophysiological aspects of regulation and compensation of cerebral circulation.

Vertebral artery aneurysms and the risk of cord infarction following spinal artery coverage during flow diversion.

Coverage of the anterior spinal artery (ASA) ostia is a source of considerable consternation regarding flow diversion (FD) in vertebral artery (VA) aneurysms due to cord supply. The authors sought to assess the association between coverage of the ASA, posterior spinal artery (PSA), or lateral spinal artery (LSA) ostia when placing flow diverters in distal VAs and clinical outcomes, with emphasis on cord infarction. A multicenter retrospective study of 7 institutions in which VA aneurysms were treated with FD between 2011 and 2019 was performed. The authors evaluated the risk of ASA and PSA/LSA occlusion, associated thromboembolic complication, complications overall, aneurysm occlusion status, and functional outcome. Sixty patients with 63 VA and posterior inferior cerebellar artery aneurysms treated with FD were identified. The median aneurysm diameter was 7 mm and fusiform type was the commonest morphology (42.9%). During a procedure, 1 (61.7%) or 2 (33.3%) flow diverters were placed. Complete occlusion was achieved in 71.9%. Symptomatic thromboembolic complications occurred in 7.4% of cases and intracranial hemorrhage in 10.0% of cases. The ASA and PSA/LSA were identified in 51 (80.9%) and 35 (55.6%) complications and covered by the flow diverter in 29 (56.9%) and 13 (37.1%) of the procedures, respectively. Patency after flow diverter coverage on last follow-up was 89.2% for ASA and 100% for PSA/LSA, not significantly different between covered and noncovered groups (p = 0.5 and p > 0.99, respectively). No complications arose from coverage. FD aneurysm treatment in the posterior circulation with coverage of ASA or PSA/LSA was not associated with higher rates of occlusion of these branches or any instances of cord infarction.

Cervical Spinal Cord Infarction Presenting as Chest Pain in Patients with Acute Cerebellar Infarction

Spinal cord infarction is rare, especially cervical cord infarction is lesser than thoracic and lumbar level. We describe two cases of cervical cord infarction following cerebellar infarction with vertebral artery occlusion, which initially presented with chest pain and dyspnea. Blood supply for the cervical cord comes from anterior and posterior spinal artery, which originated from the distal vertebral or posterior inferior cerebellar arteries. Therefore, occlusion of unilateral vertebral artery could cause a cervical cord infarction.

腰痛という非特異的症状で発症した特発性後脊髄動脈領域の脊髄梗塞：症例報告(Atypical presentation of spinal cord infarction due to posterior spinal artery occlusion: a case report)

要旨 脊髄梗塞は発症頻度が脳卒中の約1%と稀で，発症すると重篤な神経症状を呈する疾患である。今回，腰痛という非特異的な主訴で受診し，診断に時間を要した特発性後脊髄動脈領域の脊髄梗塞を経験したので報告する。症例は50歳代の男性で，腰痛とその後に発症した左下肢の痺れを主訴に救急外来を受診した。麻痺や神経脱落症状はなく，鎮痛剤の内服で疼痛は改善し独歩可能であったため整形外科受診を指示し帰宅とした。帰宅後約8時間で排尿障害と下肢脱力が出現したため救急外来を再度受診した。同日の脊髄MRIで異常所見は指摘できなかったが精査目的に入院となった。翌日のMRIでは第11胸椎から第1腰椎椎体レベルの髄内にT2強調画像（T2WI）および拡散強調画像（diffusion weighted image: DWI）で淡い高信号を認め後脊髄動脈領域の脊髄梗塞と診断した。塞栓源を検索したが原因は指摘できなかった。第24病日に回復期リハビリテーション病院へ転院した。退院後3か月でのmodified Rankin Scaleは1であった。脊髄梗塞の症状は障害される血管の支配域により様々である。とくに後脊髄動脈領域の脊髄梗塞は症状の発症から完成までに時間を要することがあり，MRIで急性期には異常所見が現れないこともあるため，鑑別に挙げた際には神経学的所見とMRI所見を十分に確認し治療にあたる必要がある。

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

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

A Microanatomical Study of the Far Lateral Approach

The far-lateral approach (FLA) remains a challenge for neurosurgeons due to the complex anatomy of this region, especially in patients with anatomical variations. There is therefore an urgent need for better quantitative knowledge of the microsurgical anatomy of the FLA. The study was performed using the dried skulls and atlas vertebrae of 50 Chinese adults, in which significant clinical parameters were measured. We further used 12 cadaveric heads to simulate the FLA to explore the step-by-step anatomy entailed by this procedure, enabling us to obtain key images and related information. Limited to hypoglossal canal, the occipital condyle posterior was abraded by roughly 10 mm, which provided good exposure to the ventral front of the foramen magnum. When occipital artery exits the occipital groove, the mean diameter was 2.20 mm. The average occipital artery suboccipital segment length was 65.26 mm. The posterior spinal artery (PSA) and posterior inferior cerebellar artery (PICA) generally originated from the fourth vertebral artery segment intradurally, and the mean distances from the PSA and PICA to the dural entry point of the vertebral artery were 2.62 mm and 8.71 mm, respectively. The incidence of PSA and PICA arising from the third vertebral artery segment was 16.67% and 4.17%, respectively. Understanding the important anatomic structures of the CVJ region and developing improved knowledge of the microsurgical anatomy of the FLA offer an opportunity to ensure safe exposure and treatment of lesions in the ventral and ventrolateral regions of the CVJ.

Microsurgical Treatment of Recurrent Conus Medullaris Arteriovenous Malformation: 2-Dimensional Operative Video.

Arteriovenous malformations (AVMs) involving the conus medullaris have a unique angioarchitecture due to their involvement of the arterial basket of the conus medullaris, which represents an arterial anastomotic network between the anterior spinal artery (ASA) and posterior spinal arteries (PSAs) at the level of the conus medullaris.1 These lesions consist of a combination of a true AVM nidus, which is usually extramedullary, and direct shunts between the ASA, PSAs, and the venous system. Patients may present with radiculopathy, myelopathy, or subarachnoid hemorrhage.2A 40-yr-old woman status post T11-L1 laminoplasty for resection of a ruptured conus AVM 6 yr prior presented with routine follow-up angiography suggestive of an arteriovenous fistula. She was counseled regarding treatment options including endovascular embolization and microsurgical ligation or resection, and she elected to proceed with surgical treatment. At the time of surgery, a recurrent AVM was noted. A 2-dimensional intraoperative video illustrates the microsurgical treatment of her recurrent conus AVM. The patient recovered well postoperatively. Spinal angiography demonstrated complete obliteration of the lesion. The patient experienced transient urinary retention that was self-limited but otherwise was without any new neurological deficit. Due to the retrospective nature of this report, informed consent was not required.Video used with permission from Barrow Neurological Institute, all rights reserved.

A Patient with Upper Cervical Spinal Cord Infarction Presenting with the Sudden Onset of Severe Occipital Headache Followed by Occipital Neuralgia

A 78-year-old man suddenly developed a severe occipital headache, followed by right greater occipital neuralgia (ON). Brain MR imaging revealed a spinal cord infarction in the territory of the right posterior spinal artery (PSA) at the C2 level without vertebral artery (VA) dissection. Even without VA dissection, upper cervical PSA syndrome could cause severe occipital headache. Furthermore, ipsilateral ON could follow it. The present case suggests that severe occipital headache and ON can occur in a patient with upper cervical PSA syndrome without VA dissection.

Anatomical Variation in Morphometry and Morphology of the Foramen Magnum and Occipital Condyle in Dried Adult Skulls.

The foramen magnum (FM) is the largest opening and is outlet through which medulla oblongata and spinal cord along with meninges, vertebral arteries, anterior and posterior spinal arteries, tectorial membrane, alar ligaments, and spinal branch of the accessory nerve. Occipital condyle (OC) is an important part of craniovertebral or craniocervical junction located anterolaterally on either side of the FM. The objective of the study was to assess variations of FM and OC in Ethiopian dried adult skulls. Observation-based descriptive study design was employed. The study was undertaken in 54 FM and 108 OC of 54 adult Ethiopian skulls. The morphometry of FM and OC were determined using a sliding vernier caliper. The mean values of anteroposterior and transverse diameters of the FM were 35.19 and 30.17 mm, respectively, and the mean area of the FM was 853.36 mm. The shapes of FM were determined as round in 22.2%, oval in 18.5%, egg like in 20.4%, triangular in 3.7%, pentagonal in 11.1%, hexagonal in 7.4%, irregular in 13%, and rectangular in 3.7% of the cases. The mean length of right and left OC was 25.69 and 26.96 mm, respectively, and the mean widths of the right and left OC were 12.76 and 13.04 mm, respectively. Our study identified various shapes of FM and diameter. The anteroposterior diameter is greater than the transverse diameter. The morphometric study of OC confirmed the length of left side is significantly greater than the right side.

Spinal Cord Infarction in the Region of the Posterior Spinal Artery After Embolization for Vertebral Artery Dissection.

Endovascular surgery for vertebral artery dissections (VADs) carries the risk of spinal cord infarction (SCI). Although SCI in the region of the anterior spinal artery (ASA) has been reported, SCI in the region of the posterior spinal artery (PSA) is rare. To investigate PSA infarction after endovascular surgery for VAD. Infarction in the region of the PSA after endovascular surgery for VADs carried out in consecutive 21 cases was investigated. The variables of aneurysmal location, status, intra-aneurysmal thrombosis, antithrombotic therapy, and endovascular procedure were investigated in relation to the occurrence of spinal cord or brain stem infarction. Thirteen cases were unruptured aneurysms, and 8, ruptured aneurysms. The endovascular surgical method was internal trapping in 10 cases, stent-assisted coil embolization in 8 cases, and proximal occlusion (PO) in 3 cases. Periprocedural symptomatic infarction was detected in 4 of the 21 cases (19%): 3 SCIs and 1 lower medulla infarction, after 1 stent-assisted coil embolization and 3 PO. All 3 symptomatic SCIs were PSA infarction. On univariate analysis, the variables of posterior inferior cerebellar artery-involved-type, PO, and intraprocedural proximal flow arrest were significantly correlated with occurrence of PSA infarction. PSA infarction after endovascular surgery for VAD seems not to be a rare potential complication. Insufficiency of collateral blood flow and artery-to-artery embolism due to intraprocedural flow stagnation of the VA seem to be the possible mechanisms of PSA infarction in addition to previously reported mechanisms such as direct obliteration by the embolic materials and extended thrombosis of the VA stump.

両下肢痺れにて救急搬送された脊髄梗塞（後脊髄動脈症候群）の1例

両下肢痺れにて救急搬送された脊髄梗塞（後脊髄動脈症候群）の1例