[Persistent Primitive Arteries].

Primitive anastomotic arteries temporarily exist between the future internal carotid and vertebrobasilar arteries during the early embryonic period(between 28 and 32 days of life). The primitive trigeminal, otic, hypoglossal, and proatlantal intersegmental arteries serve as major blood channels to the developing vertebrobasilar circulation at this stage. These arteries are replaced by the posterior communicating and vertebral arteries, and the primitive anastomotic arteries rapidly regress following the development of the definitive vertebrobasilar circulation. Occasionally, these primitive anastomoses persist and are incidentally discovered after birth. Physicians who treat cerebrovascular diseases should be familiar with the anatomy and functions of these vessels. In this review, we discuss the embryonic basis of the carotid-vertebrobasilar anastomoses and the clinical significance of their persistent forms in adults.

Successful endovascular coiling of infectious cerebral aneurysm following Staphylococcus haemolyticus endocarditis.

Recent reports suggest that Staphylococcus haemolyticus can cause infective endocarditis (IE). However, no data are available regarding infectious intracranial aneurysm (IIA) following S. haemolyticus endocarditis. Endovascular coiling is a challenging approach for the treatment of IIA. We describe the case of a 63-year-old woman who suddenly developed aphasia and dysarthria following an acute cerebral infarction in her left insular and temporal cortex. After a total hysterectomy at the age of 39, the patient had suffered from recurrent bacterial pyomyositis in her legs. At admission, there was no evidence of cerebral aneurysm, as assessed by magnetic resonance angiography, and no vegetation, as assessed by transesophageal echocardiography (TEE), resulting in an incorrect diagnosis. However, subarachnoid hemorrhage and development of cerebral aneurysm in the left middle cerebral artery occurred within 1 week of hospitalization. Continuous positive blood culture results and a second TEE finally revealed that IE was caused by S. haemolyticus. Coil embolization of the IIA was successful on day 26 after symptom onset; after this procedure, the patient began to recover. This case demonstrates that S. haemolyticus-induced endocarditis can cause IIA. Endovascular coiling is a potentially effective approach to treat IIA.

Precision microcatheter shaping in vertebrobasilar aneurysm coiling.

BACKGROUND: Inventing an optimal curve on a microcatheter is required for successful intracranial aneurysm coiling. Shaping microcatheters for vertebrobasilar artery aneurysm coiling is difficult because of the vessel's long, tortuous and mobile anatomy. To overcome this problem, we devised a new method of shaping the microcatheter by using the patient's specific vessel anatomy and the highly shapable microcatheter. We report our preliminary results of treating posterior circulation aneurysms by this method. METHODS: An unshaped microcatheter (Excelsior XT-17; Stryker Neurovascular, Fremont, CA, USA) was pretreated by exposure to the patient's vessel for five minutes. The microcatheter was placed in the vicinity of the targeted aneurysm and was left in contact with the patient's vessel before extraction. This treatment precisely formed a curve on the microcatheter shaft identical to the patient's vessel anatomy. Following the pretreatment, the tip of the microcatheter was steam shaped according to the long axis of the target aneurysm. Five consecutive vertebrobasilar aneurysms were treated using this shaping method and evaluated for the clinical and anatomical outcomes and microcatheter accuracy and stability. RESULTS: All of the designed microcatheters matched the vessel and aneurysm anatomy except in one case that required a single modification. All aneurysms were successfully catheterized without the assistance of a microguidewire, and matched the long axis of the aneurysm. All microcatheters retained stability until the end of the procedure. CONCLUSIONS: A precise microcatheter shaping for a vertebrobasilar artery aneurysm may be achieved by using the patient's actual vessel anatomy and the highly shapable microcatheter.

A patient-specific intracranial aneurysm model with endothelial lining: a novel in vitro approach to bridge the gap between biology and flow dynamics.

OBJECTIVES: To develop an in vitro model for studying the biological effect of complex-flow stress on endothelial cells in three-dimensional (3D) patient-specific vascular geometry. MATERIALS AND METHODS: A vessel replica was fabricated with polydimethylsiloxanes using 3D printing technology from vascular image data acquired by rotational angiography. The vascular model was coated with fibronectin and immersed in a tube filled with a cell suspension of endothelium, and then cultured while being slowly rotated in three dimensions. Culture medium with viscosity was perfused in the circulation with the endothelialized vascular model. A computational fluid dynamics (CFD) study was conducted using perfusion conditions used in the flow experiment. The morphology of endothelial cells was observed under a confocal microscope. RESULTS: The CFD study showed low wall shear stress and circulating flow in the apex of the basilar tip aneurysm, with linear flow in the parent artery. Confocal imaging demonstrated that the inner surface of the vascular model was evenly covered with monolayer endothelial cells. After 24 h of flow circulation, endothelial cells in the parent artery exhibited a spindle shape and aligned with the flow direction. In contrast, endothelial cells in the aneurysmal apex were irregular in shape and size. CONCLUSIONS: A geometrically realistic intracranial aneurysm model with live endothelial lining was successfully developed. This in vitro model enables a new research approach combining study of the biological impact of complex flow on endothelial cells with CFD analysis and patient information, including the presence of aneurysmal growth or rupture.

Embolization for Refractory Subacute Subdural Hematoma in a Child with Severe Hemophilia Type A.

Hemophilia is an X-linked hemorrhagic disease due to coagulation factor VIII or IX deficiency with approximately 5-10% incidence of central nervous system bleeding. We present an intriguing case of a refractory subacute subdural hematoma (SDH) controlled with endovascular embolization in a hemophilic patient. A 5-year-old severe hemophilic A boy presented with a life threatening left parietal subcortical hemorrhage, for which he underwent craniotomy and evacuation of the hematoma. Recurrent hemorrhage necessitated a repeat craniotomy. This was followed by three episodes of SDH development at the craniotomy site that were treated surgically, and finally controlled with embolization in the subacute period. This case presents a novel option for treating a refractory SDH in patients with coagulation disorders.

Carotid-vertebrobasilar Anastomoses with Reference to Their Segmental Property.

The primitive carotid-vertebrobasilar anastomoses are primitive embryonic cerebral vessels that temporarily provide arterial supply from the internal carotid artery to the longitudinal neural artery, the future vertebrobasilar artery in the hindbrain. Four types known are the trigeminal, otic, hypoglossal, and proatlantal intersegmental arteries. The arteries are accompanied by their corresponding nerves and resemble an intersegmental pattern. These vessels exist in the very early period of cerebral arterial development and rapidly involute within a week. Occasionally, persistence of the carotid to vertebrobasilar anastomosis is discovered in the adult period, and is considered as the vestige of the corresponding primitive embryonic vessel. The embryonic development and the segmental property of the primitive carotid-vertebrobasilar anastomoses are discussed. This is followed by a brief description of the persisting anastomoses in adults.

Manufacture of patient-specific vascular replicas for endovascular simulation using fast, low-cost method.

Patient-specific vascular replicas are essential to the simulation of endovascular treatment or for vascular research. The inside of silicone replica is required to be smooth for manipulating interventional devices without resistance. In this report, we demonstrate the fabrication of patient-specific silicone vessels with a low-cost desktop 3D printer. We show that the surface of an acrylonitrile butadiene styrene (ABS) model printed by the 3D printer can be smoothed by a single dipping in ABS solvent in a time-dependent manner, where a short dip has less effect on the shape of the model. The vascular mold is coated with transparent silicone and then the ABS mold is dissolved after the silicone is cured. Interventional devices can pass through the inside of the smoothed silicone vessel with lower pushing force compared to the vessel without smoothing. The material cost and time required to fabricate the silicone vessel is about USD $2 and 24 h, which is much lower than the current fabrication methods. This fast and low-cost method offers the possibility of testing strategies before attempting particularly difficult cases, while improving the training of endovascular therapy, enabling the trialing of new devices, and broadening the scope of vascular research.

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.

Microcatheter Shaping for Intracranial Aneurysm Coiling Using the 3-Dimensional Printing Rapid Prototyping Technology: Preliminary Result in the First 10 Consecutive Cases.

OBJECTIVE: An optimal microcatheter is necessary for successful coiling of an intracranial aneurysm. The optimal shape may be predetermined before the endovascular surgery via the use of a 3-dimensional (3D) printing rapid prototyping technology. We report a preliminary series of intracranial aneurysms treated with a microcatheter shape determined by the patient's anatomy and configuration of the aneurysm, which was fabricated with a 3D printer aneurysm model. METHODS: A solid aneurysm model was fabricated with a 3D printer based on the data acquired from the 3D rotational angiogram. A hollow aneurysm model with an identical vessel and aneurysm lumen to the actual anatomy was constructed with use of the solid model as a mold. With use of the solid model, a microcatheter shaping mandrel was formed to identically line the 3D curvature of the parent vessel and the long axis of the aneurysm. With use of the mandrel, a test microcatheter was shaped and validated for the accuracy with the hollow model. All the planning processes were undertaken at least 1 day before treatment. The preshaped mandrel was then applied in the endovascular procedure. Ten consecutive intracranial aneurysms were coiled with the pre-planned shape of the microcatheter and evaluated for the clinical and anatomical outcomes and microcatheter accuracy and stability. RESULTS: All of pre-planned microcatheters matched the vessel and aneurysm anatomy. Seven required no microguidewire assistance in catheterizing the aneurysm whereas 3 required guiding of a microguidewire. All of the microcatheters accurately aligned the long axis of the aneurysm. The pre-planned microcatheter shapes demonstrated stability in all except in 1 large aneurysm case. CONCLUSION: When a 3D printing rapid type prototyping technology is used, a patient-specific and optimal microcatheter shape may be determined preoperatively.

Ocular thrombosis after stent-assisted coiling of a c7 (paraclinoid) internal carotid artery aneurysm. A report of two cases and literature review.

Stent-assisted coiling of paraclinoid aneurysms is widely performed in neurointerventional surgery. The most common adverse event related to this procedure is cerebral thromboembolism. However, reports on ocular thromboembolism are scarce. We report our experience with two patients who developed ocular thromboembolism following Enterprise stent-assisted coiling of paraclinoid aneurysms. We then review the available literature for the possible pathomechanism of ocular thrombosis. Ocular thromboembolism may be a risk of stent-assisted coiling when the stent traverses the orifice of the ophthalmic artery or the stent is placed in the C3 internal carotid artery. Further study is needed to clarify how to avoid this disabling complication.

Percutaneous medial saphenous artery approach for Swine central artery access.

A percutaneous medial saphenous artery catheterization technique for swine femoral access is described. The medial saphenous artery is accessed with a 22-gauge catheter-over-needle assembly, followed by 4-Fr 10-cm sheath insertion using the Seldinger technique. The 4-Fr sheath is subsequently exchanged over a 0.035-inch guidewire for a 5-Fr sheath to establish central artery access. The technique was applied to seven vessels in five swine, with successful catheterization in five vessels. The reason for failure was technical difficulty in one case and vasospasm in the other. Central artery access was still possible through direct exposure and puncture of the medial saphenous artery or the femoral artery. This technique may provide an alternative option for central artery access in swine. However, improvement in more reliable catheterization is warranted.

Optimal dose of plasmid vascular endothelial growth factor for enhancement of angiogenesis in the rat brain ischemia model.

Vascular endothelial growth factor (VEGF) administration has recently been assessed as a therapeutic strategy for ischemic diseases including brain ischemia because of its angiogenic effect. However, VEGF also causes detrimental adverse effects by increasing vascular permeability. This study examined whether plasmid human VEGF (phVEGF) administration induced angiogenic effects in the rat brain ischemia model caused by permanent ligation of both common carotid arteries, and investigated the occurrence of adverse effects. Administration of various doses (0-200 microg) of phVEGF in the temporal muscle was followed by encephalo-myo-synangiosis. Thirty days after treatment, the numbers and areas of capillaries per field in the extracted brains were analyzed with the National Institutes of Health Image software program. The maximal angiogenic effect occurred with a 100 microg dose of phVEGF in the numbers and areas of capillaries in the VEGF-treated brains. Histological examination showed no apparent adverse effects in the brain parenchyma even at the highest administration dose (200 microg) of phVEGF. The maximal angiogenic effect at the optimal dose of phVEGF can be considered under the threshold to cause serious adverse effects in the rat brain.

Treatment of experimental aneurysms with an embolic-containing device and liquid embolic agent: feasibility and angiographic and histological results.

OBJECTIVE: To assess the feasibility and analyze angiographic and histological results of experimental aneurysms treated with an embolic-containing device (ECD) and to test a liquid embolic agent (LEA), N-butyl cyanoacrylate. METHODS: Four experimental large bifurcation aneurysms and 1 large sidewall aneurysm were created in 5 dogs. These venous pouch aneurysms were occluded endosaccularly with an ECD and N-butyl cyanoacrylate. Angiographic and/or histopathological data were analyzed at 1 day (bifurcation), 1 week (bifurcation), 4 months (sidewall), 6 months (bifurcation), and 12 months (bifurcation). RESULTS: Aneurysm dimensions were 16 to 18 mm in length, 6 to 8 mm in width, and a neck measuring 6 to 8 mm. Immediately after the procedure, 2 of 4 bifurcation aneurysms were 100% occluded. In one case, glue had spilled into the parent artery. One occluded aneurysm recanalized at 6 months. One occluded aneurysm remained closed at 12 months. Histopathological analysis of the 6- and 12-month specimens showed adherence of glue to the aneurysm wall, no appreciable inflammatory response to the ECD, and aneurysm wall fibrosis with adventitial chronic inflammation. The aneurysm necks were covered by neointima with the presence of endothelialization. CONCLUSION: Within the limitations of this experimental study, treatment of large, wide-necked aneurysms with the ECD and LEA may be feasible. Suboptimal technique and ECD geometry can cause leakage of LEA into the parent vessel or incomplete apposition of the ECD/glue to the aneurysm wall. However, the ECD and glue injection technique did achieve complete occlusion in 1 aneurysm that persisted 1 year later. The histopathological findings in this instance are moderately encouraging. Further investigations of an ECD with N-butyl cyanoacrylate or another LEA are warranted.

Large ophthalmic segment aneurysms with anterior optic pathway compression: assessment of anatomical and visual outcomes after endosaccular coil therapy.

OBJECT: The optimal therapy for ophthalmic segment aneurysms with anterior optic pathway compression (AOPC) is undecided. Surgical results have been described, but the results of endovascular coil therapy have not been well documented. METHODS: The authors retrospectively reviewed data obtained in all patients who harbored unruptured ophthalmic segment aneurysms with AOPC who underwent endovascular coil therapy at their institution. They analyzed baseline and outcome visual function, aneurysm features, extent of aneurysm closure, internal carotid artery (ICA) occlusion, additional interventions, and neurological outcome. In 17 patients (16 women), age 38 to 83 years, there were 28 affected eyes. All aneurysms were greater than 10 mm in diameter. In the initial procedures 16 of 17 patients received endosaccular coils and the ICA was preserved; in one patient the aneurysm was trapped and the ICA occluded. Patients then underwent follow up for a mean of 2.90 years (range 1 month-1 1.2 years) after the last procedure. One patient died of subarachnoid hemorrhage (SAH) 1 month postoperatively and thus no follow-up data were available for this case. Vision worsened in six patients, stabilized in four, and improved in six. Twelve patients underwent 13 subsequent procedures, including endovascular ICA occlusion in seven, repeated coil therapy in five, and optic nerve decompression in one; vision improved in 83% of these cases after ICA occlusion. A second patient died of SAH 5 months after repeated coil treatment. At the final follow up, vision had improved in eight patients (50%), stabilized in four (25%), and worsened in four (25%). In 16 patients with follow-up studies, aneurysm closure was complete in eight (50%) and incomplete in eight (50%). CONCLUSIONS: The authors found that in patients with ophthalmic segment aneurysms causing chronic AOPC, endosaccular platinum coil therapy, with ICA preservation, may not benefit vision and that additional procedures may be needed. Evaluation of their results suggests that endovascular trapping of the aneurysm and sacrifice of the ICA appear to result in good visual, clinical, and anatomical outcomes.

Enhanced brain angiogenesis in chronic cerebral hypoperfusion after administration of plasmid human vascular endothelial growth factor in combination with indirect vasoreconstructive surgery.

OBJECT: Vascular endothelial growth factor (VEGF) is a secreted mitogen associated with angiogenesis. The conceptual basis for therapeutic angiogenesis after plasmid human VEGF gene (phVEGF) transfer has been established in patients presenting with limb ischemia and myocardial infarction. The authors hypothesized that overexpression of VEGF using a gene transfer method combined with indirect vasoreconstruction might induce effective brain angiogenesis in chronic cerebral hypoperfusion, leading to prevention of ischemic attacks. METHODS: A chronic cerebral hypoperfusion model induced by permanent ligation of both common carotid arteries in rats was used in this investigation. Seven days after induction of cerebral hypoperfusion, encephalomyosynangiosis (EMS) and phVEGF administration in the temporal muscle were performed. Fourteen days after treatment, the VEGF gene therapy group displayed numbers and areas of capillary vessels in temporal muscles that were 2.2 and 2.5 times greater, respectively, in comparison with the control group. In the brain, the number and area of capillary vessels in the group treated with the VEGF gene were 1.5 and 1.8 times greater, respectively, relative to the control group. CONCLUSIONS: In rat models of chronic cerebral hypoperfusion, administration of phVEGF combined with indirect vasoreconstructive surgery significantly increased capillary density in the brain. The authors' results indicate that administration of phVEGF may be an effective therapy in patients with chronic cerebral hypoperfusion, such as those with moyamoya disease.