Vitamin B6 prevents Isocarbophos-induced posterior cerebral artery injury in offspring rats through up-regulating S1P receptor expression.

We have previously reported that the long-term exposure of Isocarbophos, a kind of organophosphorus compounds, induces vascular dementia (VD) in rats. Studies have also shown that organophosphorus compounds have adverse effects on offsprings. Vitamin B6 is a coenzyme mainly involved in the regulation of metabolism and has been demonstrated to ameliorate VD. Sphingosine-1-phosphate (S1P), a biologically active lipid, plays a vital role in the cardiovascular system. However, whether S1P is involved in the therapeutic effects of Vitamin B6 on posterior cerebral artery injury has yet to be further answered. In the present study, we aimed to explore the potential influence of Vitamin B6 on Isocarbophos-induced posterior cerebral artery injury in offspring rats and the role of the S1P receptor in this process. We found that Vitamin B6 significantly improves the vasoconstriction function of the posterior cerebral artery in rats induced by Isocarbophos by the blood gas analysis and endothelium-dependent relaxation function assay. We further demonstrated that Vitamin B6 alleviates the Isocarbophos-induced elevation of ICAM-1, VCAM-1, IL-1, and IL-6 by using the enzyme-linked immunosorbent assay kits. By performing immunofluorescence and the western blot assay, we revealed that Vitamin B6 prevents the down-regulation of S1P in posterior cerebral artery injury. It is worth noting that Fingolimod, the S1P inhibitor, significantly inhibits the Vitamin B6-induced up-regulation of S1P in posterior cerebral artery injury. Collectively, our data indicate that Vitamin B6 may be a novel drug for the treatment of posterior cerebral artery injury and that S1P may be a drug target for its treatment.

[Lateral medullary stroke with extracranial course of the postero- inferior cerebellar artery]. / Accidente cerebrovascular bulbar lateral con trayecto extracraneal de la arteria cerebelosa póstero-inferior.

We present two cases of lateral medullary stroke in subjects with extracranial trajectory of the postero-inferior cerebellar artery. Case 1: a 21-year-old male who presented ataxia and right dysmetria after cervical trauma in a rugby match. Case 2: 56-year-old woman, who started with vertigo and left hemiparesis after intense physical effort. In both cases, the angiographic studies showed an extracranial trajectory of the posterior inferior cerebellar artery. This vessel rarely originates below the foramen magnum, in close relationship with the first three cervical vertebrae and the atlanto-axial joint. At this level, it is exposed to mechanical damage causing dissection, such as direct trauma, abrupt cervical manipulation or prolonged cephalic extension. Therefore, this association should be considered in patients with stroke of the lateral region of the bulb and extracranial trajectory of the posterior-inferior cerebellar artery.

Accidente cerebrovascular bulbar lateral con trayecto extracraneal de la arteria cerebelosa póstero-inferior / Lateral medullary stroke with extracranial course of the postero- inferior cerebellar artery

Presentamos dos casos de accidente cerebrovascular en sujetos con trayecto extracraneal de la arteria cerebeloso póstero-inferior. Caso 1: varón de 21 años, quien presentó ataxia y dismetría derecha luego de un traumatismo cervical en un partido de rugby. Caso 2: mujer de 56 años, quien inició con vértigo y hemiparesia izquierda luego de esfuerzo físico intenso. En ambos casos, los estudios angiográficos mostraron un trayecto extracraneal de la arteria cerebelosa póstero-inferior. Este vaso raramente se origina por debajo del foramen magno, en relación cercana con las primeras tres vértebras cervicales y la articulación atlanto-axial. En este nivel, está expuesta a daño mecánico causante de disección, como por ejemplo trauma directo, manipulación cervical abrupta o extensión cefálica prolongada. Por lo tanto, en pacientes con accidente cerebrovascular de región lateral de bulbo y trayecto extracraneal de la arteria cerebelosa póstero-inferior se debería considerar esta asociación.

We present two cases of lateral medullary stroke in subjects with extracranial trajectory of the postero-inferior cerebellar artery. Case 1: a 21-year-old male who presented ataxia and right dysmetria after cervical trauma in a rugby match. Case 2: 56-year-old woman, who started with vertigo and left hemiparesis after intense physical effort. In both cases, the angiographic studies showed an extracranial trajectory of the posterior inferior cerebellar artery. This vessel rarely originates below the foramen magnum, in close relationship with the first three cervical vertebrae and the atlanto-axial joint. At this level, it is exposed to mechanical damage causing dissection, such as direct trauma, abrupt cervical manipulation or prolonged cephalic extension. Therefore, this association should be considered in patients with stroke of the lateral region of the bulb and extracranial trajectory of the posterior-inferior cerebellar artery.

Posterior Cerebral Artery Pseudoaneurysm, a Rare Complication of Pituitary Tumor Transsphenoidal Surgery: Case Report and Literature Review.

Endoscopic endonasal transsphenoidal surgery for pituitary tumors has been the standard therapy for decades. This approach offers surgeons an effective, safe, and wide exposure to the pituitary gland, with a relatively low mortality rate and acceptable complication rates. However, severe complications, including cerebrospinal fistula, meningitis, neural component injury, and vascular injury, may occur. One of the most common and severe complications is carotid artery injury; however, only 2 posterior cerebral artery injuries with pseudoaneurysm formation have been reported previously. One of them received bypass surgery and recovered well, but the other received endovascular treatment and died of intracranial hypertension. Herein, we report a rare case of iatrogenic pseudoaneurysm formation with hemorrhage after transsphenoidal surgery, in which tumor traction-related adjacent vessel injury was most likely. Aneurysm clipping, vascular bypass, and embolization are considered reasonable choices depending on the patient's condition for iatrogenic aneurysm formation. In our case, no surgical or endovascular intervention was performed, and the aneurysm healed spontaneously 3 weeks later.

Aberrant posterior inferior cerebellar artery injury with C1 lateral mass screw placement: a case report and review of the literature.

BACKGROUND CONTEXT: Complications associated with C1 lateral mass screw placement are relatively infrequent. The most commonly feared complications include neural or vascular injury. Although both vertebral artery and internal carotid artery injuries have been discussed in the literature, there have been no reports of posterior inferior cerebellar artery (PICA) injury from C1 lateral mass screw placement. We report a case of patient who had a cerebellar stroke after C1 lateral mass screw placement, secondary to injury of an aberrant PICA. PURPOSE: To describe the normal anatomy of the PICA, the anatomic variations previously reported in the literature, the sequela and symptoms of a patient with PICA injury, and the relevance to C1 lateral mass screw placement. No previous reports of PICA injury with a cerebellar stroke have been reported with C1 lateral mass screw instrumentation. STUDY DESIGN: Case report and literature review. METHODS: The patient underwent an Occiput-C6 posterior instrumentation for a pathologic fracture, secondary to multiple myeloma. In the postoperative period, the patient was found to have dysarthria, imbalance, and dysdiadochokinesia. Urgent computed tomography confirmed well placed C1 lateral mass screws. Magnetic resonance imaging/Magnetic Resonance Angiography showed an infarct in the PICA distribution with an abnormal variant of the PICA coursing extracranially around C1. Neurologic monitoring did not detect the injury intraoperatively. RESULTS: The patient was treated with anticoagulation and he made a reasonable recovery from his stroke. CONCLUSIONS: We report the first case of an aberrant PICA injured during a C1 lateral mass screw placement, resulting in a cerebellar stroke. Consideration should be given to abnormal PICA variation when placing C1 lateral mass screws.

Posterior inferior cerebellar artery to posterior inferior cerebellar artery in situ bypass for the treatment of Bow hunter's-type dynamic ischemia in holovertebral dissection.

BACKGROUND: Bow hunter's syndrome is a rare cause of vertebrobasilar insufficiency arising from mechanical compression of the vertebral artery (VA) during rotation of the head. Surgical treatment usually involves direct decompression of the VA at the site of compression. We describe what is to our knowledge the first reported case of a posterior inferior cerebellar artery (PICA)-to-PICA in situ bypass for treatment of Bow hunter's-type ischemia in a patient with a VA dissection. CASE DESCRIPTION: The patient was a 41-year-old man who developed disabling symptoms of vertebrobasilar insufficiency after trauma when he rotated his head to the right. Dynamic angiography demonstrated a chronic dissection and stasis of flow in the right VA when his head was rotated to the right, with no obvious site of focal compression. The right VA ended in the PICA and the left VA was of good caliber. A single-photon emission computed tomography study with acetazolamide challenge confirmed brainstem ischemia and poor cerebrovascular reserve. He ultimately underwent a PICA-to-PICA in situ bypass to revascularize his right PICA territory with complete symptom resolution. CONCLUSIONS: The PICA-to-PICA in situ bypass is a useful option in the treatment of Bow hunter's-type ischemia in the absence of focal structural compression of the VA or VA stenosis.

Posterior cerebral artery P1 segment at the stoma during endoscopic third ventriculostomy in adults.

OBJECTIVES: A serious catastrophic complication of endoscopic third ventriculostomy (ETV) is basilar artery (BA) damage. Although the BA has been discussed as the cause of haemorrhage and even pseudoaneurysm, variations of the posterior cerebral artery proximal segment (P1) and its protrusion into the third ventricle floor have not been emphasised. A series of cases are reported in which the P1 segment was located at the stoma during an ETV and was at risk of perforation. Precautionary techniques for complication avoidance are described. METHODS: A retrospective review was performed of all ETVs performed in adults at our institution between 2004 and 2008. Cases were identified in which the P1 segment was noted to herniate into the stoma at the time of third ventricular floor fenestration. RESULTS: Among 65 cases reviewed, six were identified in which the P1 segment significantly herniated into an area of the stoma at the time of third ventricular floor fenestration. In no case was the P1 segment injured by the ETV procedure. Each of the six patients had opaque third ventricle floors. A 'cookie cut' technique was used in which the opaque third ventricle floor was abraded to reveal the underlying translucent membrane, offering an improved view of arteries in the basilar cisterns. In four of six patients, ETV resulted in clinical improvement. CONCLUSIONS: The posterior cerebral artery P1 segment is potentially at risk during ETV in adults as well as in children. Awareness and proper precautions may help reduce injuries to either the P1 or the basilar apex during an ETV.

Spontaneous thrombosis of a traumatic posterior cerebral artery aneurysm in a child.

Traumatic posterior circulation aneurysms are rare, especially in children. They are typically associated with severe trauma and are thought to result from either direct osseous injury or stretching or compression of an artery against the tentorium. They may grow, rupture, or both. Although spontaneous thrombosis may occur, it rarely results in complete occlusion. We report the spontaneous and complete thrombosis of a large posterior cerebral artery aneurysm in a child who presented after minor head trauma. Five-year follow-up documents the complete occlusion of the aneurysm.