Mexican Multicenter Experience of Metastatic Spinal Disease.

Background Spinal metastatic disease is a silent progressive cancer complication with an increasing prevalence worldwide. The spine is the third most common site where solid tumors metastasize. Complications involved in spinal metastasis include root or spinal cord compression, progressing to a declining quality of life as patient autonomy reduces and pain increases. The main objective of this study is to report the incidence of patients and typology of spinal metastases in three reference centers in Mexico. Methodology Retrospective cohorts of patients diagnosed with spinal metastases from January 2010 to February 2017 at the National Cancer Institute, National Rehabilitation Institute, and the Traumatology and Orthopedics Hospital "Lomas Verdes" in Mexico City were analyzed. Results A total of 326 patients (56% males) with spinal metastases were reported. The mean age was 58.06 ± 14.05 years. The main sources of spinal metastases were tumors of unknown origin in 53 (16.25%) cases, breast cancer in 67 (20.5%) cases, prostate cancer in 59 (18%) cases, myeloma in 24 (7.4%) cases, and lung cancer in 23 (7.1%) cases. Conclusions The data obtained in this analysis delivers an updated standpoint on Mexico, providing the opportunity to distinguish the current data from global references. Collecting more epidemiological information for better recording of cancer and its associated complications, as well as further studies on them, is necessary.

Single Dose of Tranexamic Acid Effectively Reduces Blood Loss in Patients Undergoing Spine Surgery: A Prospective Randomized Controlled Trial.

OBJECTIVE: To evaluate the efficacy of oral administration of tranexamic acid (TXA) in spine surgery to achieve blood loss reduction. METHODS: Sixty patients undergoing major surgery of the spine were randomly assigned into 2 groups. Group 1 was assigned as the control group and the other group comprised patients who received oral administration of TXA 2 hours before surgery. Outcome measures included intraoperative blood loss, postoperative blood loss, hematologic parameters, blood transfusion needed, and surgical complications. RESULTS: Sixty patients linked up with the inclusion criteria. Intraoperative blood loss was significantly lower in the TXA oral group than in the control group; total blood loss in the TXA group was 930.66 ± 614 mL, which was lower than in the control group, with 1075.66 ± 956.11 mL. The mean reduction of hemoglobin was almost the same in both groups. Similarly, the total transfusion package received was lower, and the number of complications and length of stay were akin in both groups. A logistic regression model was performed with patients who had blood loss >1000 mL and surgery time >230 minutes. This result was related to the risk of bleeding, with an odds ratio of 1.31, 95% confidence interval, 1.004-1.023, P = 0.004, independent of the group. CONCLUSIONS: Oral TXA is as an effective measure for reducing total blood loss among patients undergoing elective spine surgery.

[COVID-19 mortality prediction. Comparison between two scales]. / Predicción de mortalidad en COVID-19. Comparación entre dos escalas.

Background: The prognosis and mortality in patients with COVID-19 are variable. The NEWS2 (National Early Warning Score) and REMS (Rapid Emergency Medicine Score) scales can be used quickly at hospital admission to predict mortality, no studies have been found that compare their predictive performance in our population. Objective: To compare NEWS2 and REMS to predict mortality in patients with COVID-19. Material and methods: Retrospective cohort with 361 patients. The variables were collected to calculate the NEWS2 and REMS scales and the reason for hospital discharge. The predictive value for mortality was analyzed using the ROC curve, establishing the area under the curve (AUC) with 95% confidence intervals (95% CI). The cut-off point (PC) with the best sensitivity and specificity, positive predictive value (PPV) and negative predictive value (NPV), as well as relative risk (RR) with 95% CI. Results: The AUC of NEWS2 and REMS were 0.929 (95% CI: 0.903-0.956) and 0.913 (95% CI: 0.884-0.943), respectively. The PC of the NEWS2 scale was 8 points, with sensitivity 87.8% and specificity 82.1%, PPV 69.7% and NPV 93.5% and of the REMS scale of 7 points, with sensitivity 83.5% and specificity 83.7%, PPV 70.5% and NPV 91.6%. 8 or more points on the NEWS2 scale presenting a RR of 10.74 (95% CI: 6.4-18.03), and REMS 7 or more points RR 8.36 (95% CI: 5.36-13.02). Conclusion: Both tests presented good discriminative ability to predict mortality, being better according to AUC and RR in the NEWS2 scale.

Introducción: el pronóstico y mortalidad en pacientes con COVID-19 son variables. Las escalas NEWS2 (National Early Warning Score) y REMS (Rapid Emergency Medicine Score) pueden ser utilizadas rápidamente al ingreso hospitalario para predecir mortalidad, sin embargo no se encuentran estudios que comparen su rendimiento predictivo en nuestra población. Objetivo: comparar las escalas NEWS2 y REMS para predecir mortalidad en pacientes con COVID-19. Material y métodos: cohorte retrospectiva con 361 pacientes. Se recabaron las variables para calcular las escalas NEWS2 y REMS y el motivo de egreso hospitalario. El valor predictivo para mortalidad se analizó mediante curva COR, estableciendóse área bajo la curva (AUC) con intervalos de confianza al 95% (IC95%). Se determinó el punto de corte (PC) con la mejor sensibilidad y especificidad, valor predictivo positivo (VPP) y valor predictivo negativo (VPN), además de riesgo relativo (RR) con IC95%. Resultados: las AUC de NEWS2 y REMS fueron de 0.929 (IC95%: 0.903 - 0.956) y 0.913 (IC95%: 0.884 - 0.943), respectivamente. El PC de la escala NEWS2 fue de 8 puntos, con sensibilidad de 87.8% y especificidad de 82.1%, el VPP de 69.7% y el VPN de 93.5%; mientras que de la escala REMS fue de 7 puntos, con sensibilidad de 83.5% y especificidad de 83.7%, el VPP de 70.5% y el VPN de 91.6%. Un total de 8 o más puntos en la escala NEWS2 presentan un RR de 10.74 (IC95%: 6.4 - 18.03), y REMS de 7 o más puntos un RR de 8.36 (IC95%: 5.36 - 13.02). Conclusión: ambas pruebas presentaron buena capacidad discriminativa para predecir mortalidad, siendo mejor de acuerdo con AUC y RR en la escala NEWS2.

Women in Neurosurgery: First Neurosurgeon in Latin America and Current Mexican Leaders.

BACKGROUND: History has taught us that Mexican culture has been largely supported by women, despite gender prejudice from the society. Neurosurgery has not been the exception. Therefore, we investigated the challenges and influence of female neurosurgeons in Mexico. METHODS: We conducted a review of the literature and an analysis of the internal database of the Mexican Society of Neurological Surgery focusing on 3 topics: 1) the historical presence of women and gender inequality in Mexico; 2) the life and legacy of the woman who became the first neurosurgeon in Mexico and in Latin America; and 3) the participation of women in neurosurgery in the past 3 decades. RESULTS: In Latin America, the first woman in neurosurgery was María Cristina García-Sancho, who completed her neurosurgical training in 1951. Currently, women represent 6.2% of the total members of the Mexican Society of Neurological Surgery (MSNS). This percentage is still low, although data collected in this study suggest that it might increase in the next few years because 16.7% of Board Directors of the MSNS are women, the next elected president is a female neurosurgeon, and 14.5% of neurosurgery residents are women. CONCLUSIONS: Although a steady increase has occurred of women in neurosurgery in Mexico, there is still work to do, especially to overcome the barriers related to the old assumptions of the cultural and social roles of women.

Posterior Grade 4 Osteotomy With Vertebral Shortening Is Effective for the Treatment of Kyphosis Associated With Vertebral Discitis/Osteomyelitis.

BACKGROUND: In the retrospective study of a prospectively maintained database, we present a case series of patients with kyphotic deformity secondary to spinal infection treated using a posterior-only approach with 3-column shortening and posterior instrumentation. METHODS: This is a case series of patients presenting with postural deformity and sagittal imbalance treated consecutively by 1 surgeon between 2012 and 2014. Clinical assessments and radiographic evaluations were made preoperatively and at 12- and 24-month postoperative follow-ups. All patients underwent computed tomography 24 months after surgery to evaluate spinal fusion. RESULTS: The study included 5 patients with a mean age of 50 years (range, 32-60 years). Three patients had comorbidities. Three patients were classified as American Spinal Injury Association (ASIA) grade C and were not ambulatory; 2 were ASIA grade D. At follow-up, all patients were ambulatory and classified as ASIA grade E. Kyphosis was corrected from a preoperative mean of 32° (range, 15°-58°) to 10° (range, 1°-42°) at the 2-year follow-up. A mean improvement of 22° and 75% reduction in kyphosis was obtained with fixation 2 levels above and below the lesion. Interbody fusion was observed in all patients. No major complications occurred during surgery. CONCLUSIONS: Posterior grade 4 osteotomy with vertebral shortening can be performed safely in patients with kyphosis associated with vertebral discitis/osteomyelitis in the thoracolumbar region. The single approach allowed the surgeon to debride the infection, correct the kyphosis, decompress the spinal canal, and stabilize the spine. LEVEL OF EVIDENCE: 4.

Biomechanical behavior of bone tissue in spine instrumentation.

BACKGROUND: The mechanical fixation of the spine in patients with osteoporotic vertebral degeneration is a challenge for surgeons, the vertebrae selected to insert the screws may fail, endangering health and even patient's life. OBJECTIVE: The objective of the study was to study the effect of the variation of the bone density in the bone-screw interface from a three-dimensional model of the lumbar section. MATERIALS AND METHODS: The finite element method was used to model the behavior of the lumbar vertebral section when applying compression loads. RESULTS: The stresses between 2 and 3 MPa were located on the contact surface with the screw, both in the vertebral body and in the apophysis, being slightly higher in the vertebral body. CONCLUSIONS: Regardless of bone density, the contact zones between the screws are susceptible to bone tissue failure. The posterior half of the vertebral body was the most sensitive to high values of stress, while in the areas furthest from the axis of the screw stress tended to their minimum.

INTRODUCCIÓN: La fijación mecánica de la columna en pacientes con degeneración vertebral osteoporótica es un reto para los cirujanos, pues las vértebras seleccionadas para insertar los tornillos pueden fallar, poniendo en peligro la salud y la vida del paciente. OBJETIVO: Estudiar el efecto de la variación de la densidad ósea en la interfase hueso-tornillo, a partir de un modelo tridimensional de la sección lumbar. MATERIALES Y MÉTODOS: Se emplea el método de los elementos finitos para modelar el comportamiento de la sección vertebral lumbar al aplicar cargas de compresión. RESULTADOS: Los esfuerzos entre 2 y 3 MPa se ubicaron en la superficie de contacto con el tornillo, tanto en el cuerpo vertebral como en la apófisis, siendo ligeramente superiores en el cuerpo vertebral. CONCLUSIONES: Independientemente de la densidad ósea, las zonas de contacto entre el tornillo son susceptibles al fallo del tejido óseo, debido a que están próximos al esfuerzo de fallo óseo de 2.37 ± 1.14 MPa reportado en la literatura. La mitad posterior del cuerpo vertebral fue la más sensible a sufrir valores altos de esfuerzos, mientras que en las zonas más alejadas del eje del tornillo los esfuerzos tendieron a su magnitud mínima.

Tophaceous Gout in the Lumbar Spine Causing Radiculopathy. / Gota tofácea en la columna lumbar causando radiculopatía.

Tophaceous deposits in lumbar spine is considered a rare condition. We report the case of a 44-year-old patient with low back pain and radiculopathy. Radiographs revealed lytic spondylolisthesis in L5. Magnetic resonance imaging showed hypointense signal on T1 and a heterogeneous signal on T2 located in the L4-L5 interspinous space and in the left facet joint that invades left neuroforamen. The left knee ultrasound showed «double contour¼ of the medial femoral condyle. Decompressive laminectomy with arthrodesis at the level of L5-S1 was performed. The histological examination revealed amorphous material with a foreign body giant cell reaction.

Characteristics of Spinopelvic Sagittal Alignment in Lumbar Degenerative Disease.

BACKGROUND: Normal sagittal alignment shows a range of variations and normal values. This study compared sagittal vertebral alignment in patients with different degenerative lumbar diseases. METHODS: This cross-sectional study evaluated 300 patients who were enrolled between June 2016 and June 2017. Of these patients, 213 met the study criteria and were included. RESULTS: Of the 213 patients, 66 were men (31%) and 147 were women (68.2%). The mean age was 62.7 years. Diagnoses included degenerative spondylolisthesis in 116 patients (52.7%), lumbar disk degeneration in 76 patients (34.5%), lumbar spinal stenosis in 19 patients (8.6%), and lytic spondylolisthesis in 7 patients (3.2%). The most frequent Roussouly type of sagittal alignment was type 3 (33.6%), followed by type 4 (25.9%). No significant correlation was associated with Roussouly type of sagittal alignment and lumbar degenerative disease. Median sagittal vertebral alignment parameters in the series were as follows: pelvic incidence (PI), 60.55° ± 15.62°; sacral slope, 39.09° ± 12.48°; pelvic tilt, 20.92° ± 8.99°; lumbar lordosis, 33.15° ± 18.49°; and sagittal balance, 19.64 ± 55.27 mm. One hundred sixteen patients with degenerative spondylolisthesis had significant greater PI than those with other diagnoses (61.56° vs. 58.3°, respectively; P = 0.005), and patients with lumbar spinal stenosis had significantly lower PI than those with other diagnoses (55.89° vs. 60.44°, respectively; P = 0.005). CONCLUSIONS: Pelvic incidence may play a predisposing role in the pathogenesis of lumbar degenerative disease. Patients with degenerative spondylolisthesis have greater pelvic incidence with increased lumbar lordosis. In contrast, patients with spinal stenosis have lower pelvic incidence with flatter lumbar lordosis.

Pollinator-mediated interactions between cultivated papaya and co-flowering plant species.

Many modern crop varieties rely on animal pollination to set fruit and seeds. Intensive crop plantations usually do not provide suitable habitats for pollinators so crop yield may depend on the surrounding vegetation to maintain pollination services. However, little is known about the effect of pollinator-mediated interactions among co-flowering plants on crop yield or the underlying mechanisms. Plant reproductive success is complex, involving several pre- and post-pollination events; however, the current literature has mainly focused on pre-pollination events in natural plant communities. We assessed pollinator sharing and the contribution to pollinator diet in a community of wild and cultivated plants that co-flower with a focal papaya plantation. In addition, we assessed heterospecific pollen transfer to the stigmatic loads of papaya and its effect on fruit and seed production. We found that papaya shared at least one pollinator species with the majority of the co-flowering plants. Despite this, heterospecific pollen transfer in cultivated papaya was low in open-pollinated flowers. Hand-pollination experiments suggest that heterospecific pollen transfer has no negative effect on fruit production or weight, but does reduce seed production. These results suggest that co-flowering plants offer valuable floral resources to pollinators that are shared with cultivated papaya with little or no cost in terms of heterospecific pollen transfer. Although HP reduced seed production, a reduced number of seeds per se are not negative, given that from an agronomic perspective the number of seeds does not affect the monetary value of the papaya fruit.

Effectiveness of a virtual intervention for primary healthcare professionals aimed at improving attitudes towards the empowerment of patients with chronic diseases: study protocol for a cluster randomized controlled trial (e-MPODERA project).

BACKGROUND: Communities of practice are based on the idea that learning involves a group of people exchanging experiences and knowledge. The e-MPODERA project aims to assess the effectiveness of a virtual community of practice aimed at improving primary healthcare professional attitudes to the empowerment of patients with chronic diseases. METHODS: This paper describes the protocol for a cluster randomized controlled trial. We will randomly assign 18 primary-care practices per participating region of Spain (Catalonia, Madrid and Canary Islands) to a virtual community of practice or to usual training. The primary-care practice will be the randomization unit and the primary healthcare professional will be the unit of analysis. We will need a sample of 270 primary healthcare professionals (general practitioners and nurses) and 1382 patients. We will perform randomization after professionals and patients are selected. We will ask the intervention group to participate for 12 months in a virtual community of practice based on a web 2.0 platform. We will measure the primary outcome using the Patient-Provider Orientation Scale questionnaire administered at baseline and after 12 months. Secondary outcomes will be the sociodemographic characteristics of health professionals, sociodemographic and clinical characteristics of patients, the Patient Activation Measure questionnaire for patient activation and outcomes regarding use of the virtual community of practice. We will calculate a linear mixed-effects regression to estimate the effect of participating in the virtual community of practice. DISCUSSION: This cluster randomized controlled trial will show whether a virtual intervention for primary healthcare professionals improves attitudes to the empowerment of patients with chronic diseases. TRIAL REGISTRATION: ClicalTrials.gov, NCT02757781 . Registered on 25 April 2016. Protocol Version. PI15.01 22 January 2016.

[Results to 4-year follow-up of the treatment of the cervical stenosis by corpectomy, titanium mesh cage and anterior plate fixation]. / Resultados a 4 años de seguimiento del tratamiento del conducto cervical estrecho mediante corpectomía, malla de titanio y fijación anterior con placa.

BACKGROUND: Cervical spondylotic myelopathy is caused by cervical stenosis. Several techniques have been described for the treatment of multilevel disease, such as the anterior corpectomy with titanium mesh cage and anterior cervical plate placement, which has the advantage of performing a wider decompression and using the same bone as graft. However, it has caused controversy since the collapse of the mesh cage continues being a major limitation of this procedure. MATERIAL AND METHOD: A prospective 4-year follow-up study was conducted in 7 patients diagnosed with cervical stenosis, who were treated surgically by one level corpectomy with titanium mesh cage and anterior cervical plate placement, evaluating them by radiographs and clinical scales. RESULTS: 7 patients, 5 women and 2 males were studied. The most common level was C5 corpectomy (n=4). The Neck Disability Index (NDI) preoperative average was 30.01±24.32 and 4-year postoperative 16.90±32.05, with p=0.801. The preoperative and 4-year postoperative Nürick was 3.28± 48 and 3.14±1.21 respectively, with p=0.766. Preoperative lordosis was 14.42±8.03 and 4-year postoperative 17±11.67 degrees, with p=0.660. The immediate postoperative and 4-year postoperative subsidence was 2.69±2.8 and 6.11±1.61 millimeters respectively, with p=0.0001. CONCLUSIONS: Despite the small sample, the subsidence of the mesh cage is common in this procedure. No statistically significant changes were observed in the lordosis or Nürick scale and NDI.

Hybrid Decompression and Fixation Technique for the Treatment of Multisegmental Cervical Spondylotic Myelopathy.

BACKGROUND: Cervical spondilotic myelopathy (CSM) is defined as the compromise of the spinal cord due to degenerative changes of the cervical spine. It is the most common cause of spinal cord dysfunction in patients over 55 years. An early surgical management it is paramount to achieve better neurological outcome. There is still controversy regarding the appropriate surgical treatment for multisegmental CSM involving three or more levels. The hybrid decompression and fixation technique combines one or two level corpectomy and a single level discectomy in order to obtain optimum decompression and fixation in patients with multilevel cervical myelopathy. METHODS: A prospective case-control study was made between 2011 and 2013. A total of 15 patients with diagnosis of CSM received surgical treatment with an anterior hybrid decompression and fixation technique procedure. Inclusion criteria were myelopathy confirmed by radiographic studies, magnetic resonance image (MRI) and electromyography. RESULTS: During the 2010-2013 period 15 patients were managed by hybrid decompression and fixation technique. Average age 64.8 years SD9.4. The follow up period was 29.6 SD ± 9.8 months. The JOA score improved significantly to 13.8 +/- 1.9 points at follow-up (paired t test, P = 0.001), Nurick Scale preoperative was 3.3 and improved to 2.4 mean, was significantly (Wilcoxon signed rank test p=0.006) The mean C2-C7 lordosis angle was 10.8° +/- 8.9 before surgery, and 14.3° +/- 8.8 at follow-up, there was no significant loss of lordosis angle between the preoperative and follow-up measurements (Wilcoxon signed rank test, P =0.149); At follow-up, graft non fusion was seen in 1 patient (7%, k=1). CONCLUSIONS: In this small number, single surgeon, prospective series the use of a single level corpectomy and an adjacent discectomy was shown to provide similar outcomes and complication rates as alternative surgical techniques. The authors thus consider this a viable surgical alternative with some perceived advantages, a low rate of complications and a high rate of spinal fusion. Level of Evidence: IV. This study was approved by the authors' Institutional Review Board and all patients were given informed consent prior to participation in the study.

Trait-mediated indirect interactions of ant shape on the attack of caterpillars and fruits.

Mainly owing to their high diversity and abundance, ants are formidable as predators and defenders of foliage. Consequently, ants can exclude both invertebrate and vertebrate activity on plants via direct and indirect interactions as already shown in many previous studies. Here we present empirical evidence that objects resembling ant shape on dummy caterpillars were able to repel visually oriented predators. Moreover, we also show that rubber ants on dummy fruits can repel potential fruit dispersers. Our results have direct implications on the ecological and evolutionary dynamics of interactions in ant-based systems, as ant presence could affect the fitness of its partners. In short, our study highlights the importance of visual cues in interspecific interactions and opens a new way to study the effects of ant presence to test ecological and evolutionary hypotheses.

Structure and histology of extrafloral nectaries of tropical species in a mexican rain forest / Estrutura e histologia dos nectarios extraflorais de especies em uma floresta tropical no México

Although there is a large diversity of plant species with extrafloral nectaries, histological detail of these glands is poorly documented in tropical rain forest species. We characterized extrafloral nectaries using digital photographs, scanning electron microscopy and histological methods for eight plant species belonging to the Costaceae, Euphorbiaceae, Malvaceae and Salicaceae. To our knowledge, there are no previous reports on the structure of extrafloral nectaries for these species. Croton species exhibited reddish extrafloral nectaries on the petioles, surrounded by starshaped trichomes. Cnidoscolus multilobus and Omphalea oleifera showed green, elevated, extrafloral nectaries at the peduncle; C. multilobus showed abundant secretory tissue; O. oleifera revealed numerous cells with calcium oxalate crystals. Heliocarpus species showed extrafloral nectaries distributed at the base of the blade and possesses glands in the center of the extrafloral nectary surrounded by a series of parenchymatic cells. Pleuranthodendron lindenii has two extrafloral nectaries at the base of the leaves. Costus scaber has a hollow-type extrafloral nectary on the red-colored bracts of the inflorescence; nectar cavity is found in the center area of each bracts located on a yellow line. The extrafloral nectaries described in this study exhibited different morphologies and histological structures involved in the secretion of extrafloral nectar that could be related to biotic defenses, primarily by attracting ants.

Embora exista uma grande diversidade de espécies de plantas com nectários extraflorais, detalhes histológicos destas glândulas ainda é pouco documentado para espécies tropicais. Nós caracterizamos nectários extraflorais usando fotografias digitais, microscopia eletrônica de varredura e métodos histológicos para oito espécies de plantas das famílias Costaceae, Euphorbiaceae, Malvaceae e Salicaceae. Para nosso conhecimento, não há relatos anteriores sobre a estrutura dos nectários extraflorais para as espécies estudadas. Espécies de Croton exibiram nectários extraflorais avermelhadas nos pecíolos, rodeados por tricomas em forma de estrela. Cnidoscolus multilobus e Omphalea oleifera apresentaram nectários extraflorais verdes e elevados nos pedúnculos; C. multilobus apresenta tecido secretor abundante enquanto que O. oleifera apresentou numerosas células com cristais de oxalato de cálcio. Espécies de Heliocarpus apresentaram nectários extraflorais distribuídos na base da lâmina e possuíam glândulas no centro do nectário rodeadas por uma série de células de parênquima. Pleuranthodendron lindenii apresentou dois nectários extraflorais na base das folhas. Costus scaber apresenta um nectário extrafloral do tipo oco nas brácteas avermelhadas da inflorescência, e a cavidade do nectário se encontra na área central de cada bráctea localizados em uma linha amarela. Os nectários extraflorais descritos neste estudo apresentaram morfologia e estruturas histológicas diferentes envolvidas na secreção de néctar extrafloral que poderia estar relacionado com defesas bióticas, principalmente atraindo formigas.

[Profile of the patient with failed back surgery syndrome in the National Institute of Rehabilitation. Comparative analysis]. / Perfil del paciente con síndrome de columna multioperada en el Instituto Nacional de Rehabilitación. Análisis comparativo.

BACKGROUND: Failed back surgery syndrome is a complication of spine surgery that leads to chronic pain and disability, often with disastrous emotional consequences to the patient. AIM: To compare the profile of patients whose first surgery was performed in our hospital versus a group that underwent first spine surgery in a different centre. METHODS: Retrospective study with 65 patients; 18 formed group I (first spine surgery performed in our institution), and 47 patients in group II (first surgery performed in another hospital). Background, demographic, clinical features and functional status were compared. In group I the majority of the cases had a previous diagnosis of lumbar stenosis (group I 44.4% vs group II 25.5% p = 0.22), whereas disk herniation was the main diagnosis in group II (group I 22.2% vs group II 61.7% p = 0.001). The main cause of the syndrome in group I was technical error during surgery (61.1%), while in group II this cause represented only 6.3% (p=.001). Among the patients of this latter group, misdiagnosis was highly prevalent (57.4%), against no cases in group I (p=.001). The preoperative functional status between both groups and their recovery in the immediate postoperative period was similar (p = 0.68). CONCLUSIONS: This study suggests that the diagnostic and treatment standards are different between healthcare centres, specifically between academic centres vs. private practice.

Tropical forest fragmentation affects floral visitors but not the structure of individual-based palm-pollinator networks.

Despite increasing knowledge about the effects of habitat loss on pollinators in natural landscapes, information is very limited regarding the underlying mechanisms of forest fragmentation affecting plant-pollinator interactions in such landscapes. Here, we used a network approach to describe the effects of forest fragmentation on the patterns of interactions involving the understory dominant palm Astrocaryum mexicanum (Arecaceae) and its floral visitors (including both effective and non-effective pollinators) at the individual level in a Mexican tropical rainforest landscape. Specifically, we asked: (i) Does fragment size affect the structure of individual-based plant-pollinator networks? (ii) Does the core of highly interacting visitor species change along the fragmentation size gradient? (iii) Does forest fragment size influence the abundance of effective pollinators of A. mexicanum? We found that fragment size did not affect the topological structure of the individual-based palm-pollinator network. Furthermore, while the composition of peripheral non-effective pollinators changed depending on fragment size, effective core generalist species of pollinators remained stable. We also observed that both abundance and variance of effective pollinators of male and female flowers of A. mexicanum increased with forest fragment size. These findings indicate that the presence of effective pollinators in the core of all forest fragments could keep the network structure stable along the gradient of forest fragmentation. In addition, pollination of A. mexicanum could be more effective in larger fragments, since the greater abundance of pollinators in these fragments may increase the amount of pollen and diversity of pollen donors between flowers of individual plants. Given the prevalence of fragmentation in tropical ecosystems, our results indicate that the current patterns of land use will have consequences on the underlying mechanisms of pollination in remnant forests.

3D patient-specific model of the tibia from CT for orthopedic use.

OBJECTIVES: 3D patient-specific model of the tibia is used to determine the torque needed to initialize the tibial torsion correction. METHODS: The finite elements method is used in the biomechanical modeling of tibia. The geometric model of the tibia is obtained from CT images. The tibia is modeled as an anisotropic material with non-homogeneous mechanical properties. CONCLUSIONS: The maximum stress is located in the shaft of tibia diaphysis. With both meshes are obtained similar results of stresses and displacements. For this patient-specific model, the torque must be greater than 30 Nm to initialize the correction of tibial torsion deformity.

[Transpedicular dynamics stabilization in the treatment of lumbar stenosis. Fourth years follow-up]. / Estabilización dinámica transpedicular en el tratamiento del conducto lumbar estrecho. Seguimiento cuatro años.

INTRODUCTION: We need to evaluate the efficacy and safety of the use of dynamic fixation in patients with narrow lumbar through comparing the assessment of two years with 4 years of follow-up. METHODS: Prospective, longitudinal, autocontrol deliberately and sequential intervention, in lumbar stenosis patients who made treatment with dynamic stabilization posterior type Acuflex. An evaluation of four of final follow-up. RESULTS: 18 patients who completed follow-up two years results as a basis for comparison: 18 patients, 14 female and 4 male, average age 44.05 years. Pain evaluated with numerical visual scale was found in the lower back at 24 months in an average of 2.84 and 48 months in 3.26. We measured the functional level of Oswestry at two years to be 24% and at four years 22.44%, with a p = 0.373. In the magnetic resonance for classification of patients 15 Pfirrmann without changes and three with increase of a degree. According to patients 2 Modic changes one of type 0 to type III and another to type I. We have observed that five patients have required second surgery for removal of material findings. CONCLUSIONS: There is no change between 2 and 4 years in the scale of Oswestry and pain with visual numerical scale functionality. The average height in discs had change with statistical significance, in the comparative period. The intervertebral discs had changes in 3 patients with direct relationship between scale of Pfirrmann and Modic. The rest of patients keep rehydration and normal disc height.

[Use of the PEEK cage in cervical spondylosis treatment]. / Uso de caja de PEEK (Poli-ether-ether-ketona) parael tratamiento de la espondilosis cervical.

BACKGROUND: Decompression and fusion with autograft is the gold standard technique in the treatment of cervical canal strait. Using PEEK cages or boxes of non-absorbable polymer with elasticity similar to bone, radiolucent, reduces morbidity and same degree of fusion. METHODS: A case series, prospective, longitudinal, deliberate intervention, evaluation panel before and after 2 years follow-up. Discectomy and PEEK housing placement with autologous graft. Arthrodesis were evaluated, cervical lordosis, intervertebral space height, pain evaluated with Visual Analogue Scale, Neck Disability Index, operative time, intraoperative bleeding, hospital stay and complications. Statistical analysis with t Sudent, Wilcoxon and Fisher's exact text. RESULTS: Of 17 patients studied, 9 (53%) were female. Average age 62 years. The most affected level was C5-6, C6-7 with 5 patients. Melting was found at 100%. There was no sag or migration of the box, space height was conserved, but segmental lordosis was not retained. Clinical improvement in all patients as well as disability index was seen. Bleeding was on average 187 mL. CONCLUSION: With regard to symptom improvement, conservation of interspace height and back, no segmental lordosis conservation and fusion using PEEK box is consistent with the literature. We suggest using anterior plate to maintain cervical lordosis. We found a melt index of 100%. We found clinical improvement of symptoms, pain and disability, and a global loss of cervical lordosis.

Antecedentes: la descompresión y artrodesis con auto-injerto es el patrón de referencia para el tratamiento del conducto cervical estrecho. El uso de cajas de PEEK polímero no reabsorbible, con elasticidad similar al hueso, radiolúcido, y mismo grado de fusión reduce la morbilidad. aterial y métodos: estudio de serie de casos, prospectivo, longitudinal, de intervención deliberada, evaluación en grupol antes y después, seguimiento a dos años. Discoidectomía y colocación de caja de PEEK con injerto autólogo. Se evaluaron artrodesis, lordosis cervical, altura del espacio intervertebral, dolor mediante escala visual análoga, índice de discapacidad cervical, tiempo quirúrgico, sangrado transoperatorio, estancia intrahospitalaria y complicaciones. Análisis estadístico con t de Student, Wilcoxon y exacta de Fisher. Resultados: de 17 pacientes estudiados, 9 (53%) eran del sexo femenino. La edad promedio 62 años. Sangrado promedio de 187 mL. El nivel más afectado fue C5-C6, C6-C7 en cinco pacientes. Se encontró fusión al 100% sin hundimiento ni migración de la caja, altura del espacio conservada, pero no se conservó la lordosis segmentaria. Mejoría clínica en todos los pacientes, y del índice de discapacidad. Conclusión: la disminución de los síntomas, la conservación de la altura del espacio anterior y posterior, la no conservación de la lordosis segmentaria y la fusión con caja de PEEK fueron congruentes con lo reportado en la bibliografía. Se sugiere utilizar la placa anterior para mantener la lordosis cervical. El índice de fusión encontrado fue de 100%, con disminución de los síntomas de dolor y discapacidad. Pérdida de lordosis cervical global.

Resultados de biopsia guiada por tomografía axial computarizada en el síndrome de destrucción vertebral, evaluados en dos instituciones distintas / Resultados de biópsia guiada por tomografia computadorizada axial na síndrome de destruição vertebral, avaliados em duas instituições distintas / Results of computerized axial tomography-guided biopsy in the vertebral destruction syndrome, evaluated at two different institutions

OBJETIVO: Comparar resultados de biopsias vertebrales guiadas por tomografía axial computarizada, reportados por dos servicios de Anatomía Patológica distintos en pacientes con síndrome de destrucción vertebral para confirmar confiabilidad y utilidad en el diagnóstico. MÉTODOS: Se obtuvieron muestras de tejido de 21 pacientes en el periodo comprendido del 1 de marzo al 15 de julio del 2011 con el diagnóstico del síndrome de destrucción vertebral y a quienes se les realizó biopsia guiada por tomografía axial computarizada. Las muestras se enviaron en forma cegada a dos servicios de patología distintos. Los resultados fueron analizados con el método de comparación de dos proporciones. RESULTADOS: 14 pacientes fueron del género masculino (67%) y 7 del femenino (23%), edades de 28-82, con afección principalmente lumbar (48%) y torácica (38%); afectados en una vértebra en 62%, en dos en un 33% y en 3 o más niveles en 5%. Las vértebras más afectadas fueron L1, L2 y L3 (12/30 [40%]), T4 (3/30 [10%]) y T9 (3/30 [10%]). Los resultados se agruparon en categorías: 1. Osteomielitis (9/21 [43%]), 2. Tumores (7/21 [33%]), 3. Metástasis (3/21 [14%]), 4. Tejido normal (2/21 [10%]), 5. Inflamación (0/21 [0%]), 6. Muestra inadecuada (0/21 [0%]), 7. Mal de Pott (0/21 [0%]). CONCLUSIONES: De acuerdo a los valores de Z obtenidos mediante la prueba de comparación de dos proporciones no se encontró diferencia significativa entre los resultados reportados por dos los dos servicios de patología en el síndrome estudiado, determinándose que esta parte del proceso es confiable y útil en un 90%.

OBJETIVO: Comparar resultados de biópsias vertebrais guiadas por tomografia axial computadorizada, relatados por dois serviços de Anatomia Patológica distintos em pacientes com síndrome de destruição vertebral para confirmar a confiabilidade e a utilidade no diagnóstico. MÉTODOS: Foram obtidas amostras de tecido de 21 pacientes no período de 1 de março a 15 de julho de 2011, com diagnóstico de síndrome de destruição vertebral, que foram submetidos a biópsia guiada por tomografia axial computadorizada. As amostras foram enviadas de modo cego a dois serviços de patologia distintos. Os resultados foram analisados pelo método de comparação de duas proporções. RESULTADOS: 14 pacientes eram do sexo masculino (67%) e 7 do feminino (23%), com idades entre 28 e 82 e afecção predominantemente lombar (48%) e torácica (38%); 62% tinham comprometimento em uma vértebra, 33% em duas e 5% em três ou mais níveis. As vértebras mais afetadas foram L1, L2 e L3 (12/30 [40%]), T4 (3/30 [10%]) e T9 (3/30 [10%]). Os resultados foram agrupados em categorias: 1. Osteomielite (9/21 [43%]), 2. Tumores (7/21 [33%]), 3. Metástases (3/21 [14%]), 4. Tecido normal (2/21 [10%]), 5. Inflamação (0/21 [0%]), 6. Amostra inadequada (0/21 [0%]), 7. Mal de Pott (0/21 [0%]). CONCLUSÕES: De acordo com os valores de Z obtidos pela prova de comparação de duas proporções, não se encontrou diferença significante entre os resultados relatados pelos dois serviços de patologia na síndrome estudada, ficando determinado que essa parte do processo tem confiabilidade e utilidade de 90%.

OBJECTIVE: To compare results of vertebral biopsy guided by computerized axial tomography scan, reported by two different Departments of Pathology in patients with vertebral destruction syndrome to confirm the reliability and utility in the diagnosis. METHODS: Tissue samples from 21 patients were obtained March 1 to July 15, 2011, with a diagnosis of the vertebral destruction syndrome and who underwent computerized axial tomography-guided biopsy. The samples were blindly sent to two different pathology services. The results were analyzed using the two-proportion z-test. RESULTS: 14 patients were male (67%) and 7 females (23%), aged between 28 and 82, with condition predominantly lumbar (48%) and thoracic (38%); 62% had one vertebra affected, 33% ha two and 5% had three or more levels involved. The most affected vertebrae were L1, L2 and L3 (12/30 [40%]) and T9 (3/30 [10%]). The results were grouped into categories: 1. Osteomyelitis (9/21 [43%]), 2. Tumors (7/21 [33%]), 3. Metastases (3/21 [14%]), 4. Normal tissue (2/21 [10%]), 5. Inflammation (0/21 [0%]), 6. Inadequate sample (0/21 [0%]), 7. Pott's disease (0/21 [0%]). CONCLUSIONS: According to the values obtained by the two-proportion z-test, there was no significant difference between the results reported by the two departments of pathology for the syndrome studied, being determined that this part of the process has reliability and usefulness of 90%.