Fetal-type posterior cerebral artery and association of rupture in posterior communicating artery aneurysms: A systematic review and meta-analysis.

BACKGROUND: The morbidity and mortality of intracranial aneurysm rupture motivate the risk evaluation of the patient´s characteristics and aneurysm's morphology. Brain vessel variants lead to hemodynamic changes that could increase risk. This study aims to evaluate the fetal posterior cerebral artery (fPCA) as a risk factor for the formation, rupture, and recurrence of the posterior communicating artery (PComA) aneurysm. METHODS: A search strategy was performed in MEDLINE, Scopus, Web of Science, and EMBASE databases for studies that evaluated the risk of appearance, rupture, and recurrence of PComA aneurysms with the presence of fPCA. Newcastle-Ottawa Scale and AXIS were used for quality assessment. The primary and secondary outcomes were evaluated and interpreted with an odds ratio (OR) and their 95% confidence intervals (CI). RESULTS: A total of 577 articles were reviewed. Thirteen studies were included for the qualitative analysis, and ten studies for the meta-analysis. All cohort studies were classified as poor quality, and all cross-sectional studies with moderate risk. The unadjusted OR resulted in 1.57 (n = 6, 95% CI 1.13-2.19, p = <0.001, I2 =0%) between the presence of fPCA and PComA aneurysm rupture. CONCLUSION: There is a significant association of aneurysm formation and rupture of PComA aneurysms in the presence of fPCA. This may be triggered by the hemodynamic alterations caused by the variation, leading to changes in the vessel wall.

Unscrambling the Role of Redox-Active Biometals in Dopaminergic Neuronal Death and Promising Metal Chelation-Based Therapy for Parkinson's Disease.

Biometals are all metal ions that are essential for all living organisms. About 40% of all enzymes with known structures require biometals to function correctly. The main target of damage by biometals is the central nervous system (CNS). Biometal dysregulation (metal deficiency or overload) is related to pathological processes. Chronic occupational and environmental exposure to biometals, including iron and copper, is related to an increased risk of developing Parkinson's disease (PD). Indeed, biometals have been shown to induce a dopaminergic neuronal loss in the substantia nigra. Although the etiology of PD is still unknown, oxidative stress dysregulation, mitochondrial dysfunction, and inhibition of both the ubiquitin-proteasome system (UPS) and autophagy are related to dopaminergic neuronal death. Herein, we addressed the involvement of redox-active biometals, iron, and copper, as oxidative stress and neuronal death inducers, as well as the current metal chelation-based therapy in PD.

Aged rats learn Morris Water maze using non-spatial search strategies evidenced by a parameter-based algorithm.

Spatial learning and memory are used by all individuals who need to move in a space. Morris water maze (MWM) is an accepted method for its evaluation in murine models and has many protocols, ranging from the classic parameters of latency, distance, and number of crossings to the platform zone, to other more complex methods involving computerized trajectory analysis. Algorithm-based SS analysis is an alternative that enriches traditional classic parameters. We developed a non-computerized parameter-based Search Strategy Algorithm (SSA), to classify strategies and detect changes in spatial memory and learning. For this, our algorithm was validated using young and aged rats, evaluated by two observers who classified the trajectories of the rats based on the effectiveness, localization, and precision to reach the platform. SSA is classified into 10 categories, classified by effectiveness, initial direction, and precision. Traditional measurements were unable to show significant differences in the learning process. However, significant differences were identified in SSA. Young rats used a direct search strategy (SS), while aged rats preferred indirect ones. The number of platform crossings was the only variable to show the difference in the intermediate probe trial. The parameter-based algorithm represents an alternative to the computerized SS methods to analyze the spatial memory and learning process in young and age rats. We validate the use of SSA as an alternative to computerized SS analysis spatial learning acquisition. We demonstrated that aged rats had the ability to learn spatial memory tasks using different search strategies. The use of SSA resulted in a reliable and reproducible method to analyze MWM protocols.

Single sagittal craniosynostosis surgical treatment with the "Peau d́ours" technique. Single-center experience in Mexico.

Scaphocephaly (SC) is defined as an elongation of the anteroposterior axis of the skull resulting from the abnormal fusion of the sagittal suture. This study describes the "Peau d'ours" technique and results for correcting SC. We conducted a consecutive and retrospective analysis of patients treated from 2011 to 2016. We evaluated the gender, age, and surgical outcomes. A total of 53 patients were enrolled with a mean age of 19 months old. The advantages of this technique are healthy coronal and lambdoid suture preservation and symmetrical parietal bone flap opening. This technique is safe and simple to reproduce, allowing good surgical outcomes with a low incidence of secondary craniosynostosis. This technique is ideal for patients older than six months old.

Crossed anterior cerebral circulation in the anterior communicating artery complex, first case report with angiographic evidence.

INTRODUCTION: This case report illustrates a new variant in the anterior cerebral artery complex, identified during carotid angioplasty. CLINICAL CASE: A 50-year-old male patient diagnosed with left carotid stenosis was diagnosed and treated by a cerebral angiography. During the procedure, crossed circulation in the anterior cerebral artery was identified. The presence of this variation demanded to discard distal emboli or artery dissection. Angioplasty was performed and the patient followed up without neurological deficit. DISCUSSION: Among the most possible and prevalent variations in anterior circulation, none of them explain the phenomenon we observed. Therefore, a new variant is established. The knowledge about variants in cerebral circulation is important to rule out pathology. CONCLUSION: Cerebral diagnostic angiography has become more available and frequent because of the rising in endovascular tools to treat stroke patients. Considering this new variation and others is important to discard pathology.

Safety ranges in V3 segment of the vertebral artery for surgical procedures at the craniocervical junction / Rangos de seguridad en el segmento V3 de la arteria vertebral para procedimientos quirúrgicos en la unión craneocervical

The aim of this study was to establish safety ranges for the third vertebral artery segment (V3) for craneocervical procedures. Injury to V3 represents a potentially catastrophic complication. Its tortuous path and complex relationship with neighboring structures, increasing the risk. Ten male adult cadavers (20 vertebral arteries) with arterial infiltration of red latex were studied. The length, angles and anatomical measurements were obtained between the selected surgical landmarks and the portions of V3 segment. The horizontal portion has a length of 32.7 ± 3.6 mm with an angulation of 115.1 ± 8.3 degrees. The mean distances of the horizontal portion were: from the midline to the V3 groove of C1 posterior arch (24.7 ± 6.3 mm); from C1 pars interarticularis to the V3 distal loop of V3 (8.9 ± 1.4 mm). The vertical portion has a length 32.5 ± 5.6 mm with an angulation of the proximal loop of 113.6 ± 5.8 degrees. The mean distances between the C2 spinous process to the medial surface of the distal loop (43.8 ± 4.2 mm); from the C1-C2 joint to the V3 vertical portion (9.5 ± 1.5 mm); from C2 pars interarticularis to V3 in the C2 transverse foramen (6.5 ± 3.4 mm); from C2 pars interarticularis to V3 in the C1 transverse foramen (17.5 ± 4.5 mm). We reported four potential sites where V3 can be injured during four different surgical procedures: exposure of the posterior arch of C1, and pars interarticularis of C1 in the horizontal portion and exposure of the C1C2 joint, and placement of C1-C2 transarticular screws one in the vertical portion. We provide measurements of redundancy and safety ranges to reduce the risk of injury to the V3 segment during craniocervical surgical procedures.

El objetivo de este estudio fue establecer rangos de seguridad en el tercer segmento de arteria vertebral (V3) para cirugías de la región craneocervicales. La lesión de V3 representa una complicación potencialmente catastrófica. Su tortuoso trayecto y compleja relación con las estructuras aledañas, aumenta el riesgo. Se estudiaron diez cadáveres adultos masculinos (20 arterias vertebrales) con infiltración arterial de látex rojo. La longitud, ángulos y medidas anatómicas se obtuvieron respecto a los puntos de referencia quirúrgicos y las porciones del segmento V3. La porción horizontal tiene una longitud de 32,7 ± 3,6 mm con una angulación de 115,1 ± 8,3 grados. Las distancias medias de la porción horizontal fueron: desde la línea media hasta el surco V3 del arco posterior C1 (24,7 ± 6,3 mm); desde C1 pars interarticularis hasta el bucle distal V3 de V3 (8,9 ± 1,4 mm). La parte vertical tiene una longitud de 32,5 ± 5,6 mm con una angulación del bucle proximal de 113,6 ± 5,8 grados. Las distancias medias entre el proceso espinoso C2 y la superficie medial del bucle distal (43,8 ± 4,2 mm); desde la unión C1-C2 hasta la porción vertical V3 (9,5 ± 1,5 mm); de C2 pars interarticularis a V3 en el foramen transversal C2 (6,5 ± 3,4 mm); de C2 pars interarticularis a V3 en el foramen transversal C1 (17,5 ± 4,5 mm). Informamos cuatro sitios potenciales donde la V3 puede lesionarse durante cuatro procedimientos quirúrgicos diferentes: exposición del arco posterior de C1 y pars interarticularis de C1 en la porción horizontal y exposición de la articulación C1-C2, y colocación de C1-C2 Tornillos transarticulares uno en la porción vertical. Proporcionamos mediciones de los rangos de redundancia y seguridad para reducir el riesgo de lesiones en el segmento V3 durante procedimientos quirúrgicos craneocervicales.

Four-vessel occlusion model using aged male Wistar rats: a reliable model to resolve the discrepancy related to age in cerebral ischemia research.

Animal models of cerebral ischemia have typically been established and performed using young animals, even though cerebral ischemia (CI) affects primarily elderly patients. This situation represents a discrepancy that complicates the translation of novel therapeutic strategies for CI. Models of transient global CI using aged animals have demonstrated an apparent neuroprotective effect on CA1 hippocampal neurons; however, this effect is not completely understood. Our study used a model in which young (3-6 months) and aged (18-21 months) male Wistar rats were subjected to 15 min of transient global CI using the four-vessel occlusion (4 VO) model. We determined that the 4 VO model can be performed on aged rats with a slight increase in mortality rate. In aged rats, the morphological damage was completely established by the 4th day after reperfusion, displaying no difference from their younger counterparts. These results demonstrated the lack of a neuroprotective effect of aging on CA1 hippocampal neurons in aged male Wistar rats. This study determined and characterized the morphological damage to the CA1 area after 15 min of 4 VO in aged male Wistar rats, validating the use of this model in CI and aging research.

Near-peer teaching strategy in a large human anatomy course: perceptions of near-peer instructors.

Near-peer teaching (NPT) is a strategy in which senior students assume the instructor role with junior peers (mentees). Senior students develop unique skills and knowledge through NPT, an experience which extends their learning beyond content mastery. Different teaching modules featuring NPT were utilized in the human anatomy course at the School of Medicine, Autonomous University of Nuevo Leon in Monterrey, Mexico. Modules included: Theory, Clinical Hour, Imaging Anatomy, and Laboratory. The aim of this study was to assess instructor participants' perceptions on the benefits of the NPT strategy in the anatomy classroom. A survey was administered to anatomy course instructors who utilized NPT strategies during winter, fall, and spring semesters of the 2012-2013 school year. A total of 120 instructors were enrolled in the study. There were different perceptions of instructors' roles. Theory and Imaging Anatomy instructors considered themselves to be information providers and resource developers, whereas Clinical Hour and Laboratory instructors saw themselves more as facilitators, role models, and planners. All instructors' opinions on the benefits of NPT were positive. Thus, in this article, the authors find NPT to be a strategy that promotes self-learning, a vital skill.

A morphometric study of the extraocular muscles / Estudio morfométrico de los músculos extraoculares

Extraocular muscles are important references in strabismus surgery and in placement of intraorbital devices. We analyzed extraocular muscles morphometry and possible anatomical variances of 20 orbits. We report the length, width, and points of insertion of the extraocular muscles. No anatomical variations in length, width and points of insertion were found. With regard to the rectus muscles, it was found that the superior rectus and lateral rectus are the longest muscles and that the width difference between the superior and inferior rectus is greater than that between the medial and lateral rectus and that the point of insertion of the rectus muscles has a variable morphology. The superior oblique muscle was smaller in caliber than the inferior oblique, as consistent with previous anatomical studies. Knowledge of the detailed morphology of extraocular muscles is fundamental in strabismus surgery and represents a key factor for the innovation of surgical techniques and orbital procedures.

Los músculos extraoculares son importantes en la cirugía de estrabismo y en la colocación de dispositivos intraorbitarios. Analizamos la morfometría de los músculos extraoculares y las posibles variaciones anatómicas en 20 orbitas. No encontramos variantes en longitud, anchura y sitios de inserción. Los músculos rectos superior y lateral son los mas largos; la diferencia en longitud entre los músculos rectos superior e inferior es mayor a la diferencia en longitud entre los músculos rectos medial y lateral. El músculo oblicuo superior es mas pequeño en calibre que el músculo oblicuo inferior, lo que coincide con otros estudios anatómicos. El conocimiento detallado de la morfología de los músculos extraoculares es fundamental en la cirugía de estrabismo y representa un factor clave para la innovación de técnicas quirúrgicas y procedimientos en la cavidad orbitaria.

Morphometric Study of Cervical Vertebrae C3-C7 in a Population from Northeastern Mexico / Estudio Morfométrico de las Vértebras Cervicales C3-C7 en una Población del Noreste de México

Knowing the dimensions of the vertebral elements is very important for the development of instrumentation related to the cervical spine. Ethnic variations have been reported in these dimensions and, to date, there have been no morphometric studies of this area performed on the Mexican population. We conducted a morphometric study of 150 cervical vertebrae (C3-C7) obtained from a northeastern Mexican population to determine the dimensions of the bodies, pedicles, laminae, spinous processes, and superior and inferior articular processes. We did not find significant differences (p<0.05) in measurements taken of the left and right sides. The dimensions of the vertebral bodies were larger at lower levels. The pedicles of the C3 vertebra were larger in all dimensions compared to the other vertebrae. The largest height of the laminae was observed at C7 and the largest transverse length was observed at C5. The dimensions of the bodies, spinous processes, and laminae increased from C3-C7, whereas the dimensions of the pedicles and superior and inferior articular process height decreased toward the lower cervical levels.

Las mediciones de los elementos vertebrales son importantes para la instrumentación de columna cervical. Se han reportado variaciones étnicas en estas medidas y en la actualidad no existen estudios morfométricos en la población mexicana. Se realizó un estudio morfométrico en 150 vértebras cervicales (C3-C7) para determinar las medidas de los cuerpos, pedículos, láminas, procesos espinosos y articulares superiores e inferiores. No se encontraron diferencias significativas (p<0.05) en las medidas tomadas entre ambos lados. Las dimensiones de los cuerpos vertebrales se incrementan en niveles más bajos. Los pedículos de la vértebra C3 son mayores en todas sus dimensiones. La mayor altura de las láminas se observó en C7 y la mayor longitud transversal en C5. Las dimensiones del cuerpo, procesos espinosos y láminas se incrementan de C3-C7, mientras las dimensiones de los pedículos, altura de procesos articulares superiores e inferiores disminuyen en los niveles cervicales más bajos.

[Study of the vascular morphology of the lower limb nerves used as grafts]. / Estudio de la morfología vascular en los nervios de la extremidad inferior utilizados como injertos.

INTRODUCTION: The placement of a vascularized nervous graft is an option for acute nervous injuries treatment, as this has demonstrated a longer viability. OBJECTIVE: To carry out a macroscopic and microscopic analysis of the vascularity of the main lower limb nerves used as vascularized nervous grafts. MATERIALS AND METHODS: It was followed out a descriptive, transversal and non-comparative study to analyse the saphenous, the sural, the deep peroneal and the superficial peroneal nerves vascularity. This study was performed in two stages: 1) an in situ vascularity study and 2) a morphometric study. RESULTS: By the in situ study, it was demonstrated the following: the total length of the lower limb nerves used as graft, was in a decrease order: sural nerve (micro = 29.26 cm, +/- 4.05 cm), superficial peroneal nerve (micro = 28.61 cm, +/- 3.97 cm), deep peroneal nerve (micro = 26.64 cm, +/- 5.21 cm) and saphenous nerve (micro = 25.12 cm, +/- 4.42 cm). The morphometric study demonstrated that the dominant artery with the major diameter belongs to the saphenous nerve, with a diameter of 1.13 mm; then we have the superficial peroneal nerve with a 1.01 mm diameter, followed by the deep peroneal nerve with 0.91 mm, and finally the sural nerve with the smallest diameter, 0.85 mm. CONCLUSIONS: The saphenous nerve has the most appropriated morphological characteristics to be used as a vascularized graft; by the contrary the deep peroneal nerve represents the last option from all the nerves included in this study.

Teaching skills to promote clinical reasoning in early basic science courses.

Basic and superior reasoning skills are woven into the clinical reasoning process just as they are used to solve any problem. As clinical reasoning is the central competence of medical education, development of these reasoning skills should occur throughout the undergraduate medical curriculum. The authors describe here a method of teaching reasoning skills in a clinical context during a human anatomy course.

Resilience does not predict academic performance in gross anatomy.

Few studies have evaluated resilience in an academic environment as it relates to academic success or failure. This work sought to assess resilience in regular and remedial students of gross anatomy during the first and second semesters of medical school and to correlate this personal trait with academic performance. Two groups of students were compared: the first group included first-year medical students in the regular course, and the second group included first-year medical students who did not pass the regular anatomy course and so were enrolled in the remedial course. Both groups completed anonymous surveys designed to gather demographic data and establish scores on the Connor-Davidson resilience scale, which includes 25 statements rated zero to four on a Likert scale (maximum score 100). The average resilience score was the same for both groups, 80 +/- 9. The average anatomy grades differed significantly between regular students (67+/- 15.0) and remedial students (61 +/- 12.0). While there was no overall correlation between resilience score and anatomy grade, regular students with resilience scores of 75 or greater showed slightly better academic performance than their classmates. Similarly, remedial students with resilience scores of 87 or greater faired better academically. Resilience does not predict academic performance in gross anatomy, and further work is necessary to identify those intrinsic and extrinsic factors that influence students' achievements.