Post-operative complications affect survival in surgically treated metastatic spinal cord compression.

PURPOSE: The prevalence of metastatic epidural spinal cord compression (MESCC) is increasing globally due to advancements in cancer diagnosis and treatment. Whilst surgery can benefit specific patients, the complication rate can reach up to 34%, with limited reporting on their impact in the literature. This study aims to analyse the influence of major complications on the survival of surgically treated MESCC patients. METHODS: Consecutive MESCC patients undergoing surgery and meeting inclusion criteria were selected. Survival duration from decompressive surgery to death was recorded. Perioperative factors influencing survival were documented and analysed. Kaplan-Meier survival analysis at one year compared these factors. Univariate and multivariate Cox proportional hazard regression analyses were performed. Additionally, univariate analysis compared complicated and uncomplicated groups. RESULTS: Seventy-five patients were analysed. Median survival for this cohort was 229 days (95% CI 174-365). Surgical complications, low patient performance, and rapid primary tumour growth were significant perioperative variables for survival in multivariate analyses (p < 0.001, p = 0.003, and p = 0.02, respectively) with a hazard ratio of 3.2, 3.6, and 2.1, respectively. Univariate analysis showed no variables associated with complication occurrence. CONCLUSION: In this cohort, major surgical complications, patient performance, and primary tumour growth rate were found to be independent factors affecting one year survival. Thus, prioritizing complication prevention and appropriate patient selection is crucial for optimizing survival in this population.

Systemic Inflammatory Molecules Are Associated with Advanced Fibrosis in Patients from Brazil Infected with Hepatitis Delta Virus Genotype 3 (HDV-3).

BACKGROUND AND AIMS: Hepatitis Delta virus (HDV) genotype 3 is responsible for outbreaks of fulminant hepatitis in Northeastern South America. This study investigates if systemic inflammatory molecules are differentially expressed in patients with advanced fibrosis chronically infected with Hepatitis Delta virusgenotype 3(HDV-3). METHODS: Sixty-one patients from the north of Brazil coinfected with hepatitis B virus (HBV)/HDV-3 were analyzed. HDV quantification and genotyping were performed by semi-nested real-time polymerase chain reaction (RT-PCR) and restriction fragment length polymorphism (RFLP) methodologies. Ninety-two systemic inflammatory molecules (SIMs) were measured by Proximity Extension Assay (PEA) technology. The Shapiro-Wilk, Student's t-test, Mann-Whitney tests, and logistic regression analysis were used when appropriate. RESULTS: The median age was 41 years, and all patients were HBeAg negative. Advanced fibrosis or cirrhosis was diagnosed by histological staging in 17 patients, while 44 presented with minimal or no fibrosis. Advanced necroinflammatory activity correlated positively with serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Established non-invasive fibrosis scores (APRI, FIB-4, and AST/ALT ratio) revealed low sensitivities and positive predictive values (PPVs) with an AUROC maximum of 0.586. Among the 92 SIMs analyzed, MCP.4, CCL19, EN.RAGE, SCF, and IL18 showed a positive correlation with fibrosis stage. A combined score including CCL19 and MCP.4 revealed a sensitivity of 81% and an odds ratio of 2.202 for advanced fibrosis. CONCLUSIONS: Standard non-invasive fibrosis scores showed poor performance in HDV-3 infection. We here suggest that the determination of CCL19 and MCP.4 may be used to identify patients with advanced fibrosis. Moreover, this study gives novel insights into the immunopathogenesis of HDV-3 infection.

Classification of the social distance during the COVID-19 pandemic from electricity consumption using artificial intelligence.

Accurately quantifying the social distancing (SD) practice of a population is essential for governments and health agencies to better plan and adapt restrictions during a pandemic crisis. In such a scenario, the reduction of social mobility also has a significant impact on electricity consumption, since people are encouraged to stay at home and many commercial and industrial activities are reduced or even halted. This paper proposes a methodology to qualify the SD of a medium-sized city, located in the northwest of the state of Rio Grande do Sul (RS), Brazil, using data of electricity consumption measured by the municipality's energy utility. The methodology consists of combining a data set, and an average consumption profile of Sundays is obtained using data from 4-months, it is then defined as a high SD profile due to the typical lower social activities on Sundays. An supervised and an unsupervised artificial neural network (ANN) are trained with this profile and used to analyze electricity consumption of this city during the COVID-19 pandemic. Low, moderate, and high SD ranges are also created, and the daily population behavior is evaluated by the ANNs. The results are strongly correlated and discussed with government restrictions imposed during the analyzed period and indicate that the ANNs can correctly classify the intensity of SD practiced by people. The unsupervised ANN is used more easily and in different scenarios, so it can be indicated for use by public administration for purposes of assess the effectiveness of SD policies based on the guidelines established during the COVID-19 pandemic.

Living with Chronic Pain: A Qualitative Study of the Daily Life of Older People with Chronic Pain in Chile.

One of the main causes of chronic pain in older people is spine deformity, an abnormal curvature of the spine. The purpose of this study is to improve understanding of the experience of chronic pain produced by spinal deformity in older people and understand how cultural factors may affect this experience. A qualitative study was performed with 10 older people. Participants were encouraged to describe a typical day in their life, including the factors that affect their pain and how their quality of life had been affected since experiencing chronic pain. The semistructured interviews were transcribed and analyzed using open coding. Pain caused by spine deformity produces disability, affecting how older people perform their daily activities, causing them to adapt their households and physical positions to perform these tasks, albeit slowly or incompletely. Chronic pain also affects emotional states and social relationships because older people become unable to undertake physical activities that they performed in the past. The close relationship with adult children and friends, typical in Latin cultures, is a source of comfort and support. At a community level, adaptation of public services (such as public transportation) must be improved.

Prevalence of lumbar high-intensity zone: assessment using a screening tool independent of spinal symptoms.

High-intensity zone is an area of high-intensity signal within the posterior annulus fibrosus observed in magnetic resonance imaging; initially described in painful discs, recent studies have described similar prevalence in symptomatic and asymptomatic subjects. Since its' prevalence in the general population has not been established, we used a screening tool independent of spinal symptoms to determine high-intensity zone prevalence. We studied 217 patients evaluated with abdominal-pelvic magnetic resonance imaging; we looked for high-intensity zone, disc degeneration, spondylolysis, spondylolisthesis, Modic changes and scoliosis. We determined if these variables, age and sex affected the presence of high-intensity zone; through a logistic regression analysis we evaluated their independent effect. Patients' mean age was 56.3±17.4 years; 66.8% were females. Prevalence of high-intensity zone (11.06%) was larger in males (18.06%) than females (7.59%), p = 0.02. Patients with and without high-intensity zone did not differ in age or presence of scoliosis. High-intensity zone was more frequent in degenerated discs, but not in levels with spondylolisis, spondylolisthesis or Modic changes. Male sex (OR = 2.3, 1.04-5.38) and disc degeneration (OR = 6.76, 1.77-25.81) independently influenced the presence of high-intensity zone. The prevalence of high-intensity zone in this sample of the general population, including 217 subjects, was 11.06%. Similarly, a recent meta-analysis mentioned a 9.5% prevalence in asymptomatic subjects; on the other hand it stressed a 10.4% prevalence in symptomatic subjects. All these data do not plead for a strict correlation between high-intensity zone and low back pain complaints.

The Tutankhamun Technique in Hip Arthroscopy.

Hip arthroscopy has been increasing tremendously in the past decade and is a very common surgical procedure to repair femoroacetabular impingement. To access the hip joint, distraction is mandatory to treat intra-articular disorders such as labral tears, cartilage loose bodies, and ligamentum teres tears and to evaluate the condition of the femoral head and acetabular cartilage. To distract the hip, counterdistraction is needed, and this is achieved with placement of a bulky and cushioned perineal post. Most of the described techniques in hip arthroscopy use a perineal post, whereas others use beanbags to place the patient's body on the surgical table. Still others do not use a post at all but rather use gravity and a Trendelenburg position to achieve distraction. Our technique does not use a perineal post but instead uses heavy-duty tape over the patient's upper body, which is placed on a normal operating room table to distract the hip while entering the central compartment.

StraightenUp+: Monitoring of Posture during Daily Activities for Older Persons Using Wearable Sensors.

Monitoring the posture of older persons using portable sensors while they carry out daily activities can facilitate the process of generating indicators with which to evaluate their health and quality of life. The majority of current research into such sensors focuses primarily on their functionality and accuracy, and minimal effort is dedicated to understanding the experience of older persons who interact with the devices. This study proposes a wearable device to identify the bodily postures of older persons, while also looking into the perceptions of the users. For the purposes of this study, thirty independent and semi-independent older persons undertook eight different types of physical activity, including: walking, raising arms, lowering arms, leaning forward, sitting, sitting upright, transitioning from standing to sitting, and transitioning from sitting to standing. The data was classified offline, achieving an accuracy of 93.5%, while overall device user perception was positive. Participants rated the usability of the device, in addition to their overall user experience, highly.

Does the META score evaluating osteoporotic and metastatic vertebral fractures have enough agreement to be used by orthopaedic surgeons with different levels of training?

PURPOSE: Differentiating osteoporotic vertebral fractures (OVF) from metastatic vertebral fractures (MVF) is difficult. A magnetic resonance imaging (MRI)-based score (META score) aiming to differentiate OVF and MVF was recently published; however, an independent agreement assessment is required before the score is used. We performed such independent agreement evaluation, including raters with different levels of training. METHODS: Sixty-four patients with confirmed OVF or MVF were evaluated by six raters (three spine surgeons and three orthopaedic residents) using the META score. We used the intra-class correlation coefficient (ICC) to evaluate inter- and intra-observer agreement and the kappa statistic (κ) to determine the agreement for individual score criteria. We calculated the area under the receiver-operating characteristic curve (AUC) to establish the score accuracy. RESULTS: The inter-observer agreement was poor [ICC = 0.22 (0.12-0.33)]; spine surgeons [ICC = 0.75 (0.66-0.83)] had better agreement than that of residents [ICC = 0.06 (- 0.07 to 0.23)]. The intra-observer agreement was poor [ICC = 0.15 (- 0.04 to 0.30)]; both spine surgeons [ICC = 0.21 (0.05-0.41)] and residents exhibited poor agreement [ICC = - 0.06 (- 0.40 to 0.20)]. The agreement for each specific criterion varied from κ = 0.24 to κ = 0.38. The AUC was 0.57 (0.64 for spine surgeons and 0.51 for residents, p < 0.01). CONCLUSION: The inter-observer agreement using the META score was adequate for spine surgeons but not for residents; the intra-observer agreement was poor. These results do not support the standard use of the META score to differentiate OVF and MVF. These slides can be retrieved under Electronic Supplementary Material.

O receptor de quimiocina CXCR3/CD183 na tuberculose / The chemokine receptor CXCR3/CD183 in tuberculosis

Introdução: o receptor CXCR3/CD183 juntamente com seu indutor IFNy e seus ligantes CXCL9, CXCL10 e CXCL11 têm sido descritos como de grande importância na resposta imune do perfil T helper 1 (Th1). Este grupo de quimiocinas é expresso no microambiente e permite a migração de células ao sítio da infecção para combater o patógeno. Objetivo: revisar o atual estado da arte sobre o papel do receptor CXCR3/CD183 na tuberculose. Metodologia: o presente estudo inclui a revisão narrativa de 12 artigos que foram selecionados a partir de 74 artigos encontrados nas bases de dados PubMed e Sciencedirect entre primeiro de agosto e 31 de outubro de 2014. Resultados: diferentes abordagens vêm sendo utilizadas para o estudo desse receptor. A utilização de modelos animais como camundongos, coelhos e macacos é a mais comum. Porém, ensaios in vitro com células humanas do sangue periférico e efusão pleural também já foram utilizados para representar, com maior fidelidade, a resposta ao Mycobacterium tuberculosis (Mtb) pelo sistema imune humano. Esses estudos resultaram em importantes achados sobre o papel do receptor CXCR3 na tuberculose (TB), principalmente quanto à expressão em linfócitos e neutrófilos, assim como o padrão de coexpressão de outros receptores. Conclusão: o CXCR3 é o receptor de uma importante citocina (IP-10) induzida pelo IFN-gama, produzida na resposta Th1, eficaz na resposta à tuberculose. Nesse trabalho, resssalta-se que foram encontrados poucos estudos sobre o tema e isso demonstra a necessidade de realização de novas pesquisas, a fim de melhor investigar o papel desse importante receptor na tuberculose.

Introduction: the CXCR3/CD183 receptor along with its IFNy inducer and its ligands: the chemokines named CXCL9, CXCL10 and CXCL11 are of great importance in the Th1 (T helper 1) immune response. This group of chemokine modulates the migration of cells to the site of infection to defend against the pathogen. Objective: to investigate the current state of the art on the role of the receptor CXCR3/CD183 in tuberculosis. Methodology: the present study includes the narrative review of 12 articles that were selected from 74 articles found in the PubMed and Sciencedirect databases between August 1 and October 31, 2014. Results: different approaches have been used for the study of this receptor. The use of animal models such as mice, rabbits and monkeys is more common. However, in vitro assays with human peripheral blood cells and pleural effusion were also used to represent more faithfully the response to Mycobacterium tuberculosis (Mtb) by the human immune system. These studies resulted in significant findings on the role of the CXCR3 receptor in tuberculosis (TB), especially for expression in lymphocytes and neutrophils, as well as the pattern of co-expression of other receptors. Conclusion: CXCR3 is the receptor for an important cytokine (IP-10) induced by IFN-gamma, produced in the Th1 response, effective in responding to tuberculosis. In this work, it is emphasized that cheeses found few studies on the subject and demonstration, the need for conducting research, in order to better investigate the role of this important receptor in tuberculosis.

The META score for differentiating metastatic from osteoporotic vertebral fractures: an independent agreement assessment.

BACKGROUND CONTEXT: Differentiating osteoporotic vertebral fractures (OVFs) from metastatic vertebral fractures (MVFs) is an important clinical challenge. A novel magnetic resonance imaging (MRI)-based score (the META score) was described, aiming to differentiate OVF from MVF. This score showed an almost perfect agreement by the group developing it, but an independent agreement evaluation is pending. PURPOSE: We aimed to perform an independent inter- and intraobserver agreement evaluation of the META score and to test the score's capability of differentiating OVF from MVF. STUDY DESIGN: This is an agreement study of the META score. METHODS: Sixty-four patients with confirmed OVF or MVF were assessed by six independent evaluators (three spine surgeons and three fellowship-trained radiologists) using the META score. We used the intraclass correlation coefficient (ICC) to determine the overall inter-and intraobserver agreement, and the kappa statistic (κ) to express the agreement for each individual score criterion. The score accuracy was determined by calculating the area under the receiver operating characteristic curve. Finally, we used κ to evaluate the agreement among raters to determine whether the fracture was OVF or MVF. RESULTS: The overall interobserver agreement was poor [ICC=0.10 (0.02-0.20)]; spine surgeons [ICC=0.75 (0.66-0.83)] had better agreement than radiologists did [ICC=0.05 (-0.08 to 0.21)]. The intraobserver agreement was poor [ICC=0.17 (0.01-0.32)]; both spine surgeons [ICC=0.21 (0.05-0.41)] and radiologists had a poor agreement [ICC=0.03 (-0.29 to 0.27)]. The agreement for each specific criterion varied from κ=0.24 to κ=0.60. The area under the receiver operating characteristic curve was 0.58 (0.64 for spine surgeons and 0.52 for radiologists, p<.01). CONCLUSIONS: The interobserver agreement using the META score was adequate for spine surgeons but not for other potential users (radiologists); the intraobserver agreement was poor. Further studies are thus necessary before the use of this score is recommended.

Lumbar paraspinal muscle fat infiltration is independently associated with sex, age, and inter-vertebral disc degeneration in symptomatic patients.

PURPOSE: To determine the association of paraspinal muscles and psoas relative cross-sectional area (RCSA) and fat signal fraction (FSF) with sex, age, and intervertebral disc degeneration (IDD) in symptomatic patients. METHODS: We retrospectively evaluated 80 adult patients with spinal symptoms using T2-weighted magnetic resonance images. We determined RCSA and FSF of the paraspinal muscles (erector spinae and multifidus) and psoas from L1-L2 to L5-S1; we determined IDD using the Pfirrmann classification. We compared differences in muscle RCSA and FSF based on sex and IDD, and we correlated age and IDD with RCSA and FSF. Using multivariate linear regression analyses, we determined the impact of sex, age, and IDD on RCSA and FSF. RESULTS: Men exhibited larger psoas RCSA but not larger paraspinal muscles RCSA than women. Women had larger FSF in the paraspinal muscles and psoas. Increasing IDD was associated with larger FSF if ≥2 Pfirrmann grades were observed. IDD correlated with FSF of the paraspinal muscles, and age correlated with FSF of the paraspinal muscles and psoas. IDD was less consistently correlated with RCSA, but age correlated negatively with RCSA of all three muscles. Linear regression analyses demonstrated that sex, age, and IDD were each independently associated with FSF of the paraspinal muscles; additionally, sex and age, but not IDD, were associated with psoas FSF. RCSA was less consistently influenced by these three variables. CONCLUSIONS: Sex, age, and IDD are independently associated with paraspinal muscles FSF; only sex and age influence psoas FSF.

Understanding Monitoring Technologies for Adults With Pain: Systematic Literature Review.

BACKGROUND: Monitoring of patients may decrease treatment costs and improve quality of care. Pain is the most common health problem that people seek help for in hospitals. Therefore, monitoring patients with pain may have significant impact in improving treatment. Several studies have studied factors affecting pain; however, no previous study has reviewed the contextual information that a monitoring system may capture to characterize a patient's situation. OBJECTIVE: The objective of this study was to conduct a systematic review to (1) determine what types of technologies have been used to monitor adults with pain, and (2) construct a model of the context information that may be used to implement apps and devices aimed at monitoring adults with pain. METHODS: A literature search (2005-2015) was conducted in electronic databases pertaining to medical and computer science literature (PubMed, Science Direct, ACM Digital Library, and IEEE Xplore) using a defined search string. Article selection was done through a process of removing duplicates, analyzing title and abstract, and then reviewing the full text of the article. RESULTS: In the final analysis, 87 articles were included and 53 of them (61%) used technologies to collect contextual information. A total of 49 types of context information were found and a five-dimension (activity, identity, wellness, environment, physiological) model of context information to monitor adults with pain was proposed, expanding on a previous model. Most technological interfaces for pain monitoring were wearable, possibly because they can be used in more realistic contexts. Few studies focused on older adults, creating a relevant avenue of research on how to create devices for users that may have impaired cognitive skills or low digital literacy. CONCLUSIONS: The design of monitoring devices and interfaces for adults with pain must deal with the challenge of selecting relevant contextual information to understand the user's situation, and not overburdening or inconveniencing users with information requests. A model of contextual information may be used by researchers to choose possible contextual information that may be monitored during studies on adults with pain.

An Independent Inter- and Intraobserver Agreement Evaluation of the AOSpine Subaxial Cervical Spine Injury Classification System.

STUDY DESIGN: An agreement study. OBJECTIVE: The aim of this study was to perform an independent interobserver and intraobserver agreement assessment of the AOSpine subaxial cervical spine injury classification system. SUMMARY OF BACKGROUND DATA: The AOSpine subaxial cervical spine injury classification system was recently described. It showed substantial inter- and intraobserver agreement in the study describing it; however, an independent evaluation has not been performed. METHODS: Anteroposterior and lateral radiographs, computed tomography scans, and magnetic resonance imaging of 65 patients with acute traumatic subaxial cervical spine injuries were selected and classified using the morphologic grading of the subaxial cervical spine injury classification system by 6 evaluators (3 spine surgeons and 3 orthopedic surgery residents). After a 6-week interval, the 65 cases were presented to the same evaluators in a random sequence for repeat evaluation. The kappa coefficient (κ) was used to determine the inter- and intraobserver agreement. RESULTS: The interobserver agreement was substantial when considering the fracture main types (A, B, C, or F), with κ = 0.61 (0.57-0.64), but moderate when considering the subtypes: κ = 0.57 (0.54-0.60). The intraobserver agreement was substantial considering the fracture types, with κ = 0.68 (0.62-0.74) and considering subtypes, κ = 0.62 (0.57-0.66). No significant differences were observed between spine surgeons and orthopedic residents in the overall inter- and intraobserver agreement, or in the inter- and intraobserver agreement of specific A, B, C, or F type of injuries. CONCLUSION: This classification allows adequate agreement among different observers and by the same observer on separate occasions. Future prospective studies should determine whether this classification allows surgeons to decide the best treatment for patients with subaxial cervical spine injuries. LEVEL OF EVIDENCE: 3.

The Mayo Table Technique in Hip Arthroscopy.

Hip distractor devices or hip fracture tables (HFTs) are vital to perform a reliable hip arthroscopy (HA) for the treatment of femoroacetabular impingement, especially when labral tears, chondral-labral delaminations, ligamentum teres tears, and other intraarticular disorders are present. Adequate hip distractors were not available in the early days of HA; most of HFTs being used those days were rigid, cumbersome, and did not allow us to properly perform an arthroscopic dynamic impingement test to evaluate and assess the femoral head and its site of impingement. The mayo table technique was developed because of the lack of appropriate hip instrumentation and an HFT when the author (A.P.S.) started to perform HA. This easy technique allows the surgeon to control hip maximal range of motion and also to assess completely the cam deformity in the posterolateral, superolateral, anterior, and anteroinferior aspects. It also allows the surgeon to revise where the cam is impinging and afterward perform a complete bony resection and decompression. We strongly believe that with the mayo table technique HA can be performed simply and reliably in old rigid and cumbersome HFTs and also hip distractors that do not allow an adequate dynamic assessment of the hip with maximal range of motion.

A comparative agreement evaluation of two subaxial cervical spine injury classification systems: the AOSpine and the Allen and Ferguson schemes.

PURPOSE: We performed an agreement study using two subaxial cervical spine classification systems: the AOSpine and the Allen and Ferguson (A&F) classifications. We sought to determine which scheme allows better agreement by different evaluators and by the same evaluator on different occasions. METHODS: Complete imaging studies of 65 patients with subaxial cervical spine injuries were classified by six evaluators (three spine sub-specialists and three senior orthopaedic surgery residents) using the AOSpine subaxial cervical spine classification system and the A&F scheme. The cases were displayed in a random sequence after a 6-week interval for repeat evaluation. The Kappa coefficient (κ) was used to determine inter- and intra-observer agreement. RESULTS: Inter-observer: considering the main AO injury types, the agreement was substantial for the AOSpine classification [κ = 0.61 (0.57-0.64)]; using AO sub-types, the agreement was moderate [κ = 0.57 (0.54-0.60)]. For the A&F classification, the agreement [κ = 0.46 (0.42-0.49)] was significantly lower than using the AOSpine scheme. Intra-observer: the agreement was substantial considering injury types [κ = 0.68 (0.62-0.74)] and considering sub-types [κ = 0.62 (0.57-0.66)]. Using the A&F classification, the agreement was also substantial [κ = 0.66 (0.61-0.71)]. No significant differences were observed between spine surgeons and orthopaedic residents in the overall inter- and intra-observer agreement, or in the inter- and intra-observer agreement of specific type of injuries. CONCLUSION: The AOSpine classification (using the four main injury types or at the sub-types level) allows a significantly better agreement than the A&F classification. The A&F scheme does not allow reliable communication between medical professionals.

The Pfirrmann classification of lumbar intervertebral disc degeneration: an independent inter- and intra-observer agreement assessment.

PURPOSE: Grading inter-vertebral disc degeneration (IDD) is important in the evaluation of many degenerative conditions, including patients with low back pain. Magnetic resonance imaging (MRI) is considered the best imaging instrument to evaluate IDD. The Pfirrmann classification is commonly used to grade IDD; the authors describing this classification showed an adequate agreement using it; however, there has been a paucity of independent agreement studies using this grading system. The aim of this study was to perform an independent inter- and intra-observer agreement study using the Pfirrmann classification. METHODS: T2-weighted sagittal images of 79 patients consecutively studied with lumbar spine MRI were classified using the Pfirrmann grading system by six evaluators (three spine surgeons and three radiologists). After a 6-week interval, the 79 cases were presented to the same evaluators in a random sequence for repeat evaluation. The intra-class correlation coefficient (ICC) and the weighted kappa (wκ) were used to determine the inter- and intra-observer agreement. RESULTS: The inter-observer agreement was excellent, with an ICC = 0.94 (0.93-0.95) and wκ = 0.83 (0.74-0.91). There were no differences between spine surgeons and radiologists. Likewise, there were no differences in agreement evaluating the different lumbar discs. Most differences among observers were only of one grade. Intra-observer agreement was also excellent with ICC = 0.86 (0.83-0.89) and wκ = 0.89 (0.85-0.93). CONCLUSIONS: In this independent study, the Pfirrmann classification demonstrated an adequate agreement among different observers and by the same observer on separate occasions. Furthermore, it allows communication between radiologists and spine surgeons.

Do thoraco-lumbar spinal injuries classification systems exhibit lower inter- and intra-observer agreement than other fractures classifications?: A comparison using fractures of the trochanteric area of the proximal femur as contrast model.

INTRODUCTION: It has been postulated that the complex patterns of spinal injuries have prevented adequate agreement using thoraco-lumbar spinal injuries (TLSI) classifications; however, limb fracture classifications have also shown variable agreements. This study compared agreement using two TLSI classifications with agreement using two classifications of fractures of the trochanteric area of the proximal femur (FTAPF). MATERIAL AND METHODS: Six evaluators classified the radiographs and computed tomography scans of 70 patients with acute TLSI using the Denis and the new AO Spine thoraco-lumbar injury classifications. Additionally, six evaluators classified the radiographs of 70 patients with FTAPF using the Tronzo and the AO schemes. Six weeks later, all cases were presented in a random sequence for repeat assessment. The Kappa coefficient (κ) was used to determine agreement. RESULTS: Inter-observer agreement: For TLSI, using the AOSpine classification, the mean κ was 0.62 (0.57-0.66) considering fracture types, and 0.55 (0.52-0.57) considering sub-types; using the Denis classification, κ was 0.62 (0.59-0.65). For FTAPF, with the AO scheme, the mean κ was 0.58 (0.54-0.63) considering fracture types and 0.31 (0.28-0.33) considering sub-types; for the Tronzo classification, κ was 0.54 (0.50-0.57). Intra-observer agreement: For TLSI, using the AOSpine scheme, the mean κ was 0.77 (0.72-0.83) considering fracture types, and 0.71 (0.67-0.76) considering sub-types; for the Denis classification, κ was 0.76 (0.71-0.81). For FTAPF, with the AO scheme, the mean κ was 0.75 (0.69-0.81) considering fracture types and 0.45 (0.39-0.51) considering sub-types; for the Tronzo classification, κ was 0.64 (0.58-0.70). CONCLUSION: Using the main types of AO classifications, inter- and intra-observer agreement of TLSI were comparable to agreement evaluating FTAPF; including sub-types, inter- and intra-observer agreement evaluating TLSI were significantly better than assessing FTAPF. Inter- and intra-observer agreements using the Denis classification were also significantly better than agreement using the Tronzo scheme.

Structural parameters determining the strength of the porcine vertebral body affected by tumours.

Spinal metastatic disease could lead to catastrophic consequences for the patient. However, the structural parameters that explain the weakening of vertebrae affected by tumours are not fully understood. In this study, we developed a specimen-specific finite element model to predict the strength of the porcine vertebra with simulated tumours and used it to find the structural parameters determining the strength. We validated our model with mechanical testing and then we analysed the compressive strength of intact vertebrae and seven defects with different size and shape. The results showed that the minimum bone mineral mass of the cross section and areal defect fraction were the best predictors of the normalized strength. We also found that areal parameters appeared to be better predictors than the volumetric ones. In conclusion, reduction in bone strength for vertebrae weakened by metastatic tumours is mostly associated with decrease in the mechanical properties of the cross section.

Does Pathogen Identification Influence the Clinical Outcomes in Patients With Pyogenic Spinal Infections?

STUDY DESIGN: Retrospective study. OBJECTIVE: To study the clinical outcomes of patients suffering from pyogenic spinal infections (PSI), by comparing the outcomes of patients with an identified microbiological agent with those of patients without an identified pathogen. SUMMARY OF BACKGROUND DATA: PSI is associated with significant risks for morbidity and mortality. Specific antibiotic treatment has been considered a key to successful medical treatment; however, clinicians frequently treat patients with PSI without an identified agent. A paucity of data is available comparing the clinical outcomes of patients with or without an identified pathogen. MATERIALS AND METHODS: The records of 97 consecutive patients discharged from a University Hospital with the diagnosis of PSI during a 14-year period were retrospectively reviewed. Patients' demographics, etiological agent, comorbidities, site of infection, white blood cell count, erythrocyte sedimentation rate, C-reactive protein at the time of presentation, neurological impairment, length of hospital stay, and mortality were registered to compare the clinical outcomes of patients with an identified pathogen with those of patients without an identified agent. RESULTS: The causative organism was identified in 74 patients (76.3%). Patients with microbiological diagnosis were younger, and a larger percentage of them exhibited elevated C-reactive protein value; however, they were not different from those without an identified agent in terms of sex, site of infection, comorbidities, and the presence of a concomitant infection. Our study could not demonstrate different neurological outcomes, length of stay, or mortality rates among the 2 groups. CONCLUSIONS: In a large series of patients with PSI, we did not demonstrate differences in clinical outcomes using empirical antibiotics in patients without an identified pathogen compared with patients with an identified microbiological agent receiving specific antibiotics. Future prospective multicenter studies should be conducted to obtain an answer to this important clinical question.