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OBJECTIVE: The cerebellar interpeduncular region, particularly the middle cerebellar peduncle (MCP) and interpeduncular sulcus (IPS) are significant surgical relevance areas due to the high prevalence of vascular and tumoral pathologies, such as cavernomas, arteriovenous malformations, and gliomas. We defined safer access areas of the MCP and the IPS, according to the surface anatomy, involved vessels, and fiber tracts of the cerebellar interpeduncular region. METHODS: Fifteen formalin-fixed and silicone-injected cadaveric heads and 23 human brainstems with attached cerebellums prepared with the Klingler's technique were bilaterally dissected to study the vascular and intrinsic anatomy. RESULTS: Surface anatomy: The mean length of the IPS was 12.73 mm (standard deviation [SD],2.15 mm), and the average measured angle formed by the IPS and the lateral mesencephalic sulcus was 144.53°. The mean distance from the uppermost point of the IPS to cranial nerve IV was 2.63 mm (SD, 2.84 mm). Vascular anatomy: The perforating branches of the superior cerebellar peduncle, IPS, and MCP originated predominantly from the caudal trunk of the superior cerebellar artery. The inferior third of the superior cerebellar peduncle and IPS was the third most pierced by perforating arteries, and for the MCP, was its superior third. Crossing vessels: The branches of the pontotrigeminal vein and the caudal trunk of the superior cerebellar artery crossed the IPS mostly. The superior third of the IPS was the most crossed by arteries and veins. CONCLUSIONS: The middle thirds of the IPS and MCP as entry zones might be safer than their superior and inferior thirds due to fewer perforating branches, arterial trunks, and veins crossing the sulcus as fewer eloquent tracts.

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Antecedentes: Los infartos cerebelosos suponen una entidad rara con una incidencia baja del total de ictus isquémicos. El territorio más prevalente de los infartos cerebelosos son los de la arteria cerebelosa posterior inferior (PICA). Cuando los infartos se limitan al cerebelo, los pacientes típicamente experimentan síntomas no específicos, esto hace considerar otros diagnósticos de forma errónea. Descripción del caso clínico: paciente femenina de 54 años, con antecedente de hipertensión arterial, quien presentaba cefalea insidiosa y progresiva acompañado de vértigo, alteración en la marcha y deterioro progresivo del estado de conciencia. Se realizó imagen de Resonancia Magnética Cerebral (IRM), la cual reveló zonas hiper intensas bilaterales en región cerebelosa que delimitaban territorio vascular de la arteria cerebelosa posterior inferior además dilatación moderada del sistema ventricular. Fue intervenida quirúrgicamente, realizándose craniectomía suboccipital descompresiva; posterior a la cirugía presentó mejoría clínica. Conclusiones: El ictus isquémico cerebeloso bilateral es una forma infrecuente de ictus y su presentación clínica es muy diversa. El desarrollo de las neuroimágenes, juegan un papel importante para ayudar a los médicos a seleccionar el tratamiento adecuado. Alrededor de la mitad de los pacientes con infartos cerebelosos que presentan deterioro neurológico progresivo y son tratados con craniectomía suboccipital descompresiva tienen buenos resultados. El pilar fundamental de este caso fue el hacer un diagnóstico temprano de esta entidad, ya que permitió prevenir las posibles complicaciones graves asociadas al infarto cerebeloso, las cuales ocurren durante la primera semana del ictus y, por lo tanto, asegurar un pronóstico favorable para el paciente...(AU)

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Aneurysms are the most frequent issue for the posterior inferior cerebellar artery (PICA). PICA aneurysms account for 1.4% to 4.5% of all intracranial aneurysms.1-3 Although the majority of PICA aneurysms arise from their junction with the vertebral artery, they can be found in any of 5 segments.4,5 Although PICA is more prone to form nonsaccular aneurysms than other intracranial arteries, ruptured aneurysms are usually saccular.6 Nearly all PICA aneurysms are located intracranially, above the foramen magnum. Extracranial PICA aneurysms are rare, with few reports in literature.7 Microsurgical clipping remains a good treatment alternative for these aneurysms. Higher risk of rerupture has even been reported with embolization of the distal PICA aneurysm with parent artery preservation.8 Here we present the case of a 64-year-old male patient who presented right after a thunderclap headache, followed by a temporary loss of consciousness and disorientation. He was diagnosed with a modified Fisher 4 and Hunt and Hess 2 subarachnoid hemorrhage and found to have a partially thrombosed left PICA saccular aneurysm of the caudal loop just below the foramen magnum. The lesion was approached via a midline suboccipital craniotomy with C1 laminectomy. Microsurgical clipping of the aneurysm was performed without any complications (Video 1). Postoperatively, the patient was discharged without neurologic deficits. We present the first surgical video of the necessary steps in order to perform a microsurgical clipping of an extracranially located caudal loop PICA aneurysm through a midline suboccipital craniotomy with C1 laminectomy.

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OBJECTIVE: An adequate knowledge of the anterior inferior cerebellar artery (AICA) is oriented to the morphological sciences, clinical management and surgical planning of the posterior fossa. We aimed to determine the morphology of AICA in a sample from Colombian population. METHOD: We studied 92 AICA from fresh cadavers. For each specimen, the vertebral arteries were injected with 100 cc of semi-synthetic resin (a mixture of Palatal E210® BASF 80 cc and Styrene 20 cc) dyed with mineral red. The biometrics and morphological variables of AICA were registered. RESULTS: AICA originated at 9.9 ± 3.2 mm from the vertebrobasilar junction. In 12 samples (8.1%), we observed a common trunk between AICA and posterior inferior cerebellar artery, which presented a caliber of 1.56 ± 0.23 mm and a length of 11.3  ± 3. 53 mm. In 80 (51.3%) specimens, AICA was originated from the proximal segment of basilar artery, while in 76 (48.7%) of them emerged from the medium segment. The AICA bifurcation distance from its origin was less than 20 mm in 20.5% of cases; between 20 and 40 mm in 62.3%. In its trajectory, AICA passed ventral to the facial nerve in 85 samples (53.2%), dorsal to the facial nerve in 68 samples (43.6%) and between the roots in 5 samples (3.2%). CONCLUSIONS: The origin of the AICA from the proximal segment of the basilar artery is confirmed in this study, which disagrees with reports that point out its origin in the middle segment.

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Wallenberg syndrome, or lateral medullar syndrome, is the clinical presentation of the infarct in the territory of posterior inferior cerebellar artery. Its signs and symptoms include vertigo, nystagmus, diplopia, ipsilateral Horner syndrome, facial ruddiness and dry skin, dysphonia, dysphagia, dysarthria, ipsilateral loss of gag reflex, ipsilateral ataxia, ipsilateral impaired taste, ipsilateral facial pain and paresthesia, decreased ipsilateral blink reflex, contralateral hypoalgesia and thermoanaesthesia in the trunk and limbs; and ipsilateral facial hypoalgesia and thermoanaesthesia. Neuroanatomical knowledge is essential to its comprehension, study and diagnosis, because the classic neurological manifestations are easy to explain and understand if function and localization of affected anatomical structures are known as if the posterior cerebral circulation is.

El síndrome de Wallenberg, o síndrome bulbar lateral, es la manifestación clínica del infarto en el territorio de irrigación de la arteria cerebelosa posteroinferior. Su presentación incluye vértigo, nistagmo, diplopía, síndrome de Horner, rubicundez y anhidrosis facial homolateral, disfonía, disfagia, disartria, pérdida homolateral del reflejo nauseoso, ataxia homolateral, disgeusia homolateral, dolor y parestesia faciales homolaterales, pérdida o disminución homolateral del reflejo corneal, hipoalgesia y termoanestesia de tronco y extremidades contralaterales, hipoalgesia y termoanestesia facial homolateral. El conocimiento neuroanatómico es imprescindible para su comprensión, estudio y diagnóstico, ya que sus manifestaciones neurológicas clásicas son fácilmente explicables y entendibles si se conocen la función y la localización de las estructuras anatómicas afectadas, así como la irrigación cerebral posterior.

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It has been reported that growth hormone (GH) and insulin-like growth factor 1 (IGF-1) exert protective and regenerative actions in response to neural damage. It is also known that these peptides are expressed locally in nervous tissues. When the central nervous system (CNS) is exposed to hypoxia-ischemia (HI), both GH and IGF-1 are upregulated in several brain areas. In this study, we explored the neuroprotective effects of GH and IGF-1 administration as well as the involvement of these endogenously expressed hormones in embryonic chicken cerebellar cell cultures exposed to an acute HI injury. To induce neural damage, primary cultures were first incubated under hypoxic-ischemic (<5% O2, 1g/L glucose) conditions for 12 h (HI), and then incubated under normal oxygenation and glucose conditions (HI + Ox) for another 24 h. GH and IGF-1 were added either during or after HI, and their effect upon cell viability, apoptosis, or necrosis was evaluated. In comparison with normal controls (Nx, 100%), a significant decrease of cell viability (54.1 ± 2.1%) and substantial increases in caspase-3 activity (178.6 ± 8.7%) and LDH release (538.7 ± 87.8%) were observed in the HI + Ox group. On the other hand, both GH and IGF-1 treatments after injury (HI + Ox) significantly increased cell viability (77.2 ± 4.3% and 72.3 ± 3.9%, respectively) and decreased both caspase-3 activity (118.2 ± 3.8% and 127.5 ± 6.6%, respectively) and LDH release (180.3 ± 21.8% and 261.6 ± 33.9%, respectively). Incubation under HI + Ox conditions provoked an important increase in the local expression of GH (3.2-fold) and IGF-1 (2.5-fold) mRNAs. However, GH gene silencing with a specific small-interfering RNAs (siRNAs) decreased both GH and IGF-1 mRNA expression (1.7-fold and 0.9-fold, respectively) in the HI + Ox group, indicating that GH regulates IGF-1 expression under these incubation conditions. In addition, GH knockdown significantly reduced cell viability (35.9 ± 2.1%) and substantially increased necrosis, as determined by LDH release (1011 ± 276.6%). In contrast, treatments with GH and IGF-1 stimulated a partial recovery of cell viability (45.2 ± 3.7% and 53.7 ± 3.2%) and significantly diminished the release of LDH (320.1 ± 25.4% and 421.7 ± 62.2%), respectively. Our results show that GH, either exogenously administered and/or locally expressed, can act as a neuroprotective factor in response to hypoxic-ischemic injury, and that this effect may be mediated, at least partially, through IGF-1 expression.

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Abstract The report describes a case of peri-operative stroke that presented as diplopia and gait difficulty on 2nd post-operative day after routine orchidopexy under spinal anesthesia in an otherwise healthy young boy. Magnetic resonance imaging of the brain revealed acute infarct in bilateral cerebellar hemispheres, left half of medulla and left thalamus. A diagnosis of acute stroke (infarct) was made and patient was started on oral aspirin 75 mg.day-1, following which his vision started improving after 2 weeks. Possible mechanisms of development of stroke in the peri-operative period are discussed, but, even after extensive investigations, the etiology of infarct may be difficult to determine. Acute infarct after elective non-cardiac, non-neurological surgery is rare; it may not be possible to identify the etiology in all cases. Clinicians must have a high index of suspicion to diagnose such unexpected complications even after routine surgical procedures in order to decrease the morbidity and long term sequelae.

Resumo O presente relato descreve um caso de acidente vascular cerebral perioperatório que resultou em diplopia e dificuldade de marcha no segundo dia após orquidopexia de rotina sob raquianestesia em um jovem, em outros aspectos, saudável. Ressonância magnética cerebral revelou infarto agudo em hemisférios cerebelares bilaterais, metade esquerda do bulbo e tálamo esquerdo. Um diagnóstico de acidente vascular cerebral agudo (infarto) foi feito e o paciente começou a receber tratamento com aspirina oral (75 mg.dia-1), após o qual sua visão começou a melhorar após duas semanas. Possíveis mecanismos de desenvolvimento de acidente vascular cerebral no período perioperatório são discutidos, mas, mesmo após extensas investigações, a etiologia do infarto pode ser difícil de determinar. O infarto agudo após cirurgia eletiva não cardíaca e não neurológica é raro; talvez não seja possível identificar a etiologia em todos os casos. Os médicos devem ter um elevado grau de suspeita para diagnosticar essas complicações inesperadas, mesmo após procedimentos cirúrgicos de rotina, para diminuir a morbidade e as sequelas em longo prazo.

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The report describes a case of peri-operative stroke that presented as diplopia and gait difficulty on 2nd post-operative day after routine orchidopexy under spinal anesthesia in an otherwise healthy young boy. Magnetic resonance imaging of the brain revealed acute infarct in bilateral cerebellar hemispheres, left half of medulla and left thalamus. A diagnosis of acute stroke (infarct) was made and patient was started on oral aspirin 75mg.day-1, following which his vision started improving after 2 weeks. Possible mechanisms of development of stroke in the peri-operative period are discussed, but, even after extensive investigations, the etiology of infarct may be difficult to determine. Acute infarct after elective non-cardiac, non-neurological surgery is rare; it may not be possible to identify the etiology in all cases. Clinicians must have a high index of suspicion to diagnose such unexpected complications even after routine surgical procedures in order to decrease the morbidity and long term sequelae.

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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.

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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.

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