Hyaluronic Acid Embolism Treated with Subcutaneous High and Low Hyaluronidase Doses: Efficacy and Surrounding Tissue Effect.

BACKGROUND: The use of hyaluronidase in hyaluronic acid vascular occlusion has been evaluated; however, the models used do not accurately assimilate the facial morphologic characteristics or study the effects on adjacent tissues. The purpose of this study was to determine an effective concentration of subcutaneous hyaluronidase to dissolve a hyaluronic acid embolism and its effect on surrounding tissue. METHODS: Fifteen rabbits were divided into six groups. An inguinal incision was performed on the femoral artery to create a hyaluronic acid embolism in the control and treatment groups (low-, medium-, and high-hyaluronidase groups). Hyaluronidase was injected subcutaneously. Photographic follow-up, histologic analysis, and quantification of hyaluronic acid were performed. Kruskal-Wallis test and post hoc with Bonferroni correction (p < 0.05) was used to compare the presence of hyaluronic acid in the arterial lumen between groups. RESULTS: Despite the persistence of intravascular hyaluronic acid, macroscopic and microscopic differences were found between the embolism control group and embolism hyaluronidase high-dose group. Histologic analysis demonstrated thrombosis throughout groups. Skeletal muscle was least affected in the embolism hyaluronidase 500 IU group with less lysis and inflammatory infiltrate. CONCLUSIONS: A 500 IU hyaluronidase dose partially prevents the damage caused by the embolism, and does not affect the surrounding tissue. The use of thrombolytic therapy combined with higher doses of hyaluronidase subcutaneously in this model is proposed.

Comparison of suturing models: the effect on perception of basic surgical skills.

BACKGROUND: Acquisition of Basic Surgical Skills (BSS) are essential for medical students. The objective was to determine it's fidelity impact. METHODS: Using four suturing models (SM) (pigskin, sponge, commercial pad, and orange), SM-quality and student-SM interaction were evaluated. After a 1-h class, participants were divided into groups and randomly assigned exercises in SM in 15-min intervals. The experiment included completing three individual simple stitches and a 3-stitch continuous suture in each SM. RESULTS: Eighty-two medical students participated. Suturing quality was better in pigskin and sponge, which were also the preferred models (p < 0.001). Significant differences in quality between the insertion and exit point, and firmness of knots (p < 0.05) in both simple and continuous sutures, as well as between length and distance in continuous ones (p < 0.001) were identified. CONCLUSIONS: Acquisition and quality of BSS are influenced by the intrinsic characteristics of SM. An adequate degree of resistance, consistency, and elasticity are necessary.

Schwann Cell Precursor Transplant in a Rat Spinal Cord Injury Model.

BACKGROUND: Differentiation of mesenchymal stem cells into Schwann cell precursors could reverse established lesions and sequelae of medullary transection. OBJECTIVE: The objective of this study was to study the clinical response of mesenchymal stem cell transplantation with Schwann precursor cell transplantation in a rat spinal cord injury model, using motor function and histopathologic studies. MATERIALS AND METHODS: A total of 28 Sprague-Dawley rats were randomly divided among four groups (n = 7 in each): sham group, control group, mesenchymal stem cell transplant group, and Schwann cell precursor transplant group. The surgical procedure was a laminectomy with transection of the spinal cord at the T11 level in the transplant groups and the injury control group. After 1 week, the transplant groups received stem cells directly in the injury site. Hind limb motor function was assessed using the locomotive scale of Basso, Beattie, and Bresnahan. 1 month after transplantation, all specimens were sacrificed to make a histopathologic description of sections taken from the site of injury and where stem cells were transplanted. Mean scores of mobility were compared using analysis of variance (ANOVA) of one factor with 95% reliability between groups and ANOVA of repetitive measures to evaluate evolution in the same group. RESULTS: We observed that the control group had statistically greater mobility than the other groups (p < 0.0001) and that the group with spinal injury without treatment had the lowest mean mobility. The mobility score values from the Schwann cell precursor group were statistically higher than the group treated with mesenchymal stem cells (p < 0.0001). CONCLUSION: Schwann precursor cells had a greater effect on locomotive function than mesenchymal stem cells.

Human Umbilical Vessels: Choosing the Optimal Decellularization Method.

There is an increasing demand of small-diameter vascular grafts for treatment of circulatory pathologies. Decellularization offers the possibility of using human blood vessels as scaffolds to create vascular grafts. Umbilical vessels have great potential because of their availability and morphological characteristics. Various decellularization techniques have been used in umbilical vessels, but consensus on which is the most appropriate has not yet been reached. The objective of this review is to analyze the morphological and biomechanical characteristics of decellularized human umbilical arteries and veins with different techniques. Evidence indicates that the umbilical vessels are a viable option to develop small-diameter vascular grafts. Detergents are the agents most often used and with most evidence. However, further studies are needed to accurately analyze the components of the extracellular matrix and biomechanical characteristics, as well as the capacity for recellularization and in vivo functionality.

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.

[Study of peripheral nerve injury in trauma patients]. / Estudio de la lesión nerviosa periférica en pacientes atendidos por traumatismos.

OBJECTIVE: To determine the prevalence, location, mechanism, and characteristics of peripheral nerve injury (PNI) in trauma patients. MATERIAL AND METHODS: A retrospective study of medical records with PNI diagnosis secondary to trauma in the period of 2008-2012. The following information was collected: gender, age, occupation, anatomic location, affected nerve, mechanism of injury, degree of injury, costs, and hospitalization time. RESULTS: The prevalence of PNI is 1.12%. The location of the nerve injury was 61% upper limb, the highest incidence was presented to the brachial plexus (35%) and ulnar nerve (18%). The mechanism of the lesion was sharp injury (19%). DISCUSSION: The PNI are commonly present in people of a productive age. Neurotmesis was the most frequent degree of lesion. The patients stayed at hospital 2.51 ± 1.29 days and the average cost was 12,474.00 Mexican pesos ± 5,595.69 (US$ 1,007.54 ± 452.21) for one nerve injury.

Age- and gender-related variations in morphometric characteristics of thoracic spine pedicle: A study of 4,800 pedicles.

Transpedicular spinal fusion is the most commonly used fixation technique for the surgical treatment of vertebral disorders. However, the instrumentation of the thoracic spine using this technique continues to be controversial. The objective of the present study was to determine the morphometric characteristics of the thoracic pedicle and to establish how these characteristics vary with gender and age. Two hundred thoracic spines (4800 thoracic pedicles) from individuals of known gender and age were analyzed (in accordance with the order of vertebrae). The spines were divided into six groups according to age and gender. The horizontal and vertical diameters of the thoracic pedicle were determined for each piece. The mean and standard deviation of each variable were determined, and differences between age groups for each gender were evaluated using parametric correlation tests. The pedicle diameters of men and women differed significantly for most groups (P < 0.05). The horizontal diameters decreased from T1 to T5 and increased up to T12. The vertical diameter followed a cephalocaudal pattern of development from T1-T12. The pedicle diameters decreased with increasing age in women, while the opposite trend was observed in men. In men, the dimensions of the thoracic spine pedicle increase with increasing age; in women, they decrease. These differences should be taken into account when selecting the appropriate pedicle screw.

[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.

Morphometry of pedicle and vertebral body in a Mexican population by CT and fluroscopy / Morfometría del cuerpo vertebral y pedículo en una población mexicana mediante TC y fluoroscopía

It is necessary to have precise anatomical knowledge of lumbar pedicles for the safe placement of screws. There are not reports about the morphometry of lumbar pedicles in a Mexican population exist. A descriptive, observational and cross-sectional study was done in 60 cadavers from the dissection lab of the Human Anatomy Department of the Medicine School. The aim of the study was to quantify the morphometric characteristics of the pedicles of the lumbar spine in a Mexican population. A total of 60 cadavers were evaluated by fluoroscopy and CT from L1 to L5, in the age range of 40 to 78 years. Each vertebral pedicle was measured in the axial, sagittal and coronal planes. The measurements included the minimum pedicle width, the pedicle angle, the distance to anterior cortex, and anteroposterior and interpedicular spinal canal diameters. CT evaluation showed a progressive and gradual increase in the width of the pedicles from L1 (7.81 +/- 1.30 mm) to L5 (14.36 +/- 14.36 mm). A progressive and gradual decrease of pedicle length from L1 (20.92 +/- 2.62 mm) to L5 (17.23 +/- 1.35 mm). When fluoroscopy was used there was the same relationship, but the values were higher than those obtained by CT. The values for widths and lengths are slightly higher in males than in females, but do not reveal any significant difference (p<0.05). The data in this study indicates that pedicle screws (5.5-6.5mm) may be used in the lumbar region.

Es necesario tener un conocimiento anatómico preciso de la morfología de los pedículos en la region lumbar para la colocación segura de tornillos intrapediculares. No existen reportes de la morfometría de los pedículos lumbares en la población Mexicana. Se desarrolló un estudio descriptivo, observacional y transversal en 60 cadaveres en el laboratorio del Departamento de Anatomía Humana de la Facultad de Medicina. El objetivo del estudio fue determinr las características morfométricas de los pedículos de la region lumbar en una muestra de población Mexicana. Se evaluaron las regiones lumbares (L1-L5) de un total de 60 cadaveres por fluroscopía y TC en un rango de edad entre 40 y 78 años. Cada pedículo fue medido en los planos axial, sagital y coronal. La evaluacion por TC muestra un aumento progresivo y gradual de la anchura de los pedículos de L1 (7,81 +/- 1,30 mm) a L5 (14,36 +/- 14,36 mm). También se observó una disminución gradul de la longitud del pedículo de L1 (14,36 +/- 14,36 mm) a L5 (17,23 +/- 1,35 mm). Al realizar las mediciones por fluroscopia se observaron las mismas condiciones, pero los valores fueron proporcionalmente mayores que los obtenidos por TC. La anchura y longitud pedicular fueron ligeramente mayores en hombres que en mujeres, pero no revelan significancia estadística (p<0,05). Los datos obtenidos del estudio indican que los tornillos intrapediculares (5,5- 6,5mm) pueden ser utilizados en la region lumbar.

Modification of the technique for subclavian-vein catheterization.

INTRODUCTION: In invasive monitoring, subclavian-vein puncture is a routine procedure indicated for central vein cathe-terization. It is indicated in patients according to hospital stay, including the administration of drugs and the treatment of chronic and cardiac disease. The techniques described to date include infraclavicular percutaneous puncture; others place catheters using angiographic methods, and the use of magnetic resonance imaging and ultrasound has also been reported. Studies have been done in cadavers to get a better understanding of the procedure since the relationship between vascular elements and surrounding tissues are obtained. The usual technique is with the patient in Trendelenburg position, with the arm in adduction, the placement of an interscapular roll, and the head turned away from the puncture site. OBJECTIVE: The aim of this study was to demonstrate less frequent technical failures and complications using a modification of the usual technique. We propose catheterization of the right subclavian vein with the patient in decubitus, without an interescapular roll, with the arm in abduction and using the distal third of the clavicle and the suprasternal notch as anatomical references. RESULTS: Two technical puncture failures and three complications occurred in a total of 42 patients with a statistically significant difference (p = 0.0410) in frequency (11.9%) from that reported with the traditional technique (21.8%). CONCLUSIONS: Greater efficacy with the technique modified by the authors was confirmed. Anatomical cadaver dissections showed a greater space between the right subclavian vein and the clavicle.

An interactive tool for the human anatomy laboratory / Una Herramienta Interactiva para el Laboratorio de Anatomía Humana

Hasta hoy, diferentes estudios han tratado de determinar la manera más efectiva de aprender Anatomía: algunos autores apoyan el método tradicional, otros prefieren el uso de computadores y algunos creen en la integración de ambos. En nuestra Escuela de Medicina utilizamos el método tradicional y el uso de computadores, así hemos desarrollado un programa multimedia que tiene por objetivo optimizar la disección como herramienta de aprendizaje. Este programa multimedia de apoyo está adaptado al manual de disecciones que es utilizado durante el curso. El programa cuenta con 6 módulos, de 5 regiones cada uno, en los que se incluyen: imágenes fotográficas y diagramas de las regiones, información acerca de las estructuras que deben ser identificadas, radiografías, correlaciones clínicas y autoevaluaciones.

A multimedia program has been developed at the Departament of Human Anatomy, Medicine School of Universidad Autónoma de Nuevo León. It offers an alternative to support the traditional laboratory practice and resolve, during the dissection, the most common problems that we have already identify in our students. Some features of this program are: photography's, diagrams, information about the structures, clinical correlation and tests. All this tools were integrated in a software using Macromedia Flash. The final result is a multimedia program that will be used by students during their laboratory practice. At present, we are making a study to determine the effect that is produced in the development of the students in the anatomy lab.

Meningocele oculto en el sacro / Occul intrasacral meningocele

Los defectos disráficos del sistema nervioso central, la espina bífida, el meningocele y el mielomeningocele, habitualmente se manifiestan y son diagnosticados al nacer o en las primeras etapas de la vida, siendo común observar estigmas cutáneos que nos hacen sospechar la espina bífida oculta y otras lesiones intraespinales congénitas. Se reportaron tres casos de meningocele oculto en el sacro, que se manifestaron en la edad adulta, entre los 40 y 52 años con un cuadro clínico de lumbalgia, ciática y vejiga neurogénica, como característica común dilatación del conducto lumbosacro y erosión acentuada de los cuerpos vertebrales, principalmente al nivel del sacro. Fácilmente detectados en las radiografías simples. Se destaca la importancia de la tomografía axial computada TAC, resonancia magnética, mielografía y la mielografía TAC en el proceso de diagnóstico. Se señalan las bases de su tratamiento quirúrgico, que en estos tres pacientes, permitió la solución de su problema

Expansión del espacio subaracnoideo en el niño / Enlargement of subarachnoid space in child

Se presentan dos casos de niños referidos a consulta de neurocirugía por macrocranea y dilatación de los espacios subaracnoideos en la convexidad y cisternas basales. Ambos evolucionan con resolución espontánea de esta anomalía, demostrada y seguida con tomografía computarizada (TC) y resonancia magnética (RM). Sin alteraciones significativas en su desarrollo psicosomático

Meningioma del surco olfatorio / Meningioma of the olfatory sulcus

Se presenta el caso de dos pacientes con meningioma del surco olfatorio. Uno de ellos sólido y el otro quístico. Ambos pacientes del sexo masculino. Acuden a consulta por crisis convulsivas; previo al evento convulsivo, los síntomas o signos de la neoplasia pasaron desapercibidos para el paciente o sus familiares o bien no se les dio interés. Destacando la importancia de la tomografía computarizada (CT) y la resonancia magnética (MR) en el diagnóstico y en la definición de la estrategia quirúrgica

Glioma de las vías opticas / Optic glioma: two pediatric cases

Se presentan dos casos de glioma de las vías ópticas. El primero, en una niña de tres años diez meses, localizado en la porción intraorbitaria del nervio óptico izquierdo, fue diagnosticado y operado en 1977. Se hizo una resección subtotal y se aplicó radioterapia posoperatoria. Fue reoperado en 1982 con resección subtotal y se aplicó radiación con acelerador lineal. Actualmente, la paciente tiene 18 años y aparentemente esta curada, con amaurosis izquierda. El segundo caso se presenta en una niña de tres años, de localización optoquiasmática e hipotalámica late-realizado a la derecha con resección subtotal, presentando amaurosis derecha y diabetes insípida. Siendo tratada con quimioterapia posquirúrica