Levels of sCD163 in women rheumatoid arthritis: Relationship with cardiovascular risk markers.

AIM: The soluble scavenger receptor differentiation antigen 163 (sCD163), a monocyte/macrophage activation marker, is related to cardiovascular mortality in the general population. This study aimed to evaluate their relationship between serum levels of sCD163 with cardiovascular risk indicators in rheumatoid arthritis (RA). METHODS: A cross-sectional study was performed on 80 women diagnosed with RA. The cardiovascular risks were determined using the lipid profile, metabolic syndrome, and QRISK3 calculator. For the assessment of RA activity, we evaluated the DAS28 with erythrocyte sedimentation rate (DAS28-ESR). The serum levels of sCD163 were determined by the ELISA method. Logistic regression models and receiver operating characteristics (ROC) curve were used to assess the association and predictive value of sCD163 with cardiovascular risk in RA patients. RESULTS: Levels of sCD163 were significantly higher in RA patients with high sensitivity protein C-reactive to HDL-c ratio (CHR)≥0.121 (p=0.003), total cholesterol/HDL-c ratio>7% (p=0.004), LDL-c/HDL-c ratio>3% (p=0.035), atherogenic index of plasma>0.21 (p=0.004), cardiometabolic index (CMI)≥1.70 (p=0.005), and high DAS28-ESR (p=0.004). In multivariate analysis, levels of sCD163≥1107.3ng/mL were associated with CHR≥0.121 (OR=3.43, p=0.020), CMI≥1.70 (OR=4.25, p=0.005), total cholesterol/HDL-c ratio>7% (OR=6.63, p=0.044), as well as with DAS28-ESR>3.2 (OR=8.10, p=0.008). Moreover, levels of sCD163 predicted CHR≥0.121 (AUC=0.701), cholesterol total/HDL ratio>7% (AUC=0.764), and DAS28-ESR>3.2 (AUC=0.720). CONCLUSION: Serum levels of sCD163 could be considered a surrogate of cardiovascular risk and clinical activity in RA.

Sistema de planificación de actividades del Ministerio de Salud Pública e impacto en el trabajo gerencial / The Ministry of Public Health's Activities Planning System and Its Impact on Management Work

Introducción: El Ministerio de Salud Pública emplea recursos materiales, humanos, organizativos y de tiempo en la ejecución y seguimiento del sistema de planificación de actividades, por lo que se asume que hayan contribuido a la materialización de mejoras en la capacidad administrativa de todas las instituciones del sector y acortar con respuestas rápidas, integrales y evidenciadas a las demandas de los diferentes niveles de gobierno y de la población. Objetivo: Caracterizar el funcionamiento del actual procedimiento de planificación de actividades del Ministerio de Salud Pública y sus efectos en los procesos administrativos. Métodos: Se realizó una investigación cualitativa de tipo fenomenológica con enfoque gerencial, durante el período de enero de 2011 a diciembre de 2021. A partir de la aplicación de técnicas de diagrama de afinidad, emergieron categorías que se emplearon como unidades de análisis. Se organizaron los discursos desde el punto de vista de grandes efectos, efectos intermedios y causas con vistas a encontrar los efectos dominantes, se realizó la catalogación de las fallas expresadas en los discursos vistas como brechas y de esta manera darles una connotación de impacto sobre la concepción y ejecución del sistema de planificación. Resultados: Se obtuvo una caracterización evidenciada de cómo funciona el procedimiento de planificación de actividades del Ministerio de Salud Pública, sus efectos en los procesos administrativos y qué decisiones deben tomarse al efecto. Conclusiones: El procedimiento para la planificación de actividades del Ministerio de Salud Pública no logra beneficios en la eficiencia y efectividad de los procesos administrativos en el organismo y sus dependencias(AU)

Introduction: The Ministry of Public Health uses material, human, organizational and time resources in the execution and monitoring of the activities planning system, so it is assumed that they have contributed to the materialization of improvements in the administrative capacity of all the institutions of the sector and shorten with rapid, comprehensive and evidenced responses to the demands of the different levels of government and the population. Objective: To characterize the functioning of the current activity planning procedure of the Ministry of Public Health and its effects on administrative processes. Methods: A qualitative phenomenological research with a managerial approach was carried out during the period from January 2011 to December 2021. From the application of affinity diagramming techniques, categories emerged that were used as units of analysis. The discourses were organized from the point of view of large effects, intermediate effects and causes with a view to finding the dominant effects. The flaws expressed in the discourses seen as gaps were catalogued and thus given a connotation of impact on the conception and execution of the planning system. Results: It was achieved an evidence-based characterization of how the Ministry of Public Health's activities planning procedure works, its effects on administrative processes, and what decisions should be made to this end. Conclusions: The procedure for planning activities of the Ministry of Public Health does not achieve benefits in the efficiency and effectiveness of administrative processes in the agency and its dependencies(AU)

The effect of seasonality in predicting the level of crime. A spatial perspective.

This paper presents an innovative methodology to study the application of seasonality (the existence of cyclical patterns) to help predict the level of crime. This methodology combines the simplicity of entropy-based metrics that describe temporal patterns of a phenomenon, on the one hand, and the predictive power of machine learning on the other. First, the classical Colwell's metrics Predictability and Contingency are used to measure different aspects of seasonality in a geographical unit. Second, if those metrics turn out to be significantly different from zero, supervised machine learning classification algorithms are built, validated and compared, to predict the level of crime based on the time unit. The methodology is applied to a case study in Barcelona (Spain), with month as the unit of time, and municipal district as the geographical unit, the city being divided into 10 of them, from a set of property crime data covering the period 2010-2018. The results show that (a) Colwell's metrics are significantly different from zero in all municipal districts, (b) the month of the year is a good predictor of the level of crime, and (c) Naive Bayes is the most competitive classifier, among those who have been tested. The districts can be ordered using the Naive Bayes, based on the strength of the month as a predictor for each of them. Surprisingly, this order coincides with that obtained using Contingency. This fact is very revealing, given the apparent disconnection between entropy-based metrics and machine learning classifiers.

A retrospective analysis of bone loss in tenofovir-emtricitabine therapy for HIV PrEP.

BACKGROUND: Tenofovir-Emtricitabine (TDF-FTC) is known to cause bone loss in about 1-3% of HIV treated patients. Current studies lack evidence in minority groups and long-term bone loss effects in PrEP patients. SETTING: To address the risk of osteopenia/osteoporosis in patients on TDF-FTC therapy for HIV PrEP and to address the breakthrough incidence of HIV. METHODS: A retrospective analysis was performed in Kaiser Permanente patients from 2012-2021. Patients on TDF-FTC for PrEP without any prior history of osteopenia/osteoporosis (N = 7698) were analyzed to determine the relationship between PrEP adherence and osteopenia/osteoporosis. Descriptive statistics and Cox proportional hazards model were used to compare and analyze patient characteristics between those who developed osteopenia/osteoporosis and those who didn't. RESULTS: 3% were found to have osteopenia/osteoporosis. Patients who developed osteopenia/osteoporosis were more likely to have a proportion of days covered (PDC) ratio ≥90%, older, had history of Hep B, DM, CVD, CKD, hypertension, and baseline eGFR ≥90 mL/min/1.73 m2. Kaplan-Meier curve showed the event-free rate of osteopenia/osteoporosis decreased with time, with a greater reduction in patients with high adherence. Survival analysis showed only PDC of ≥90% was significantly associated with the risk of osteopenia/osteoporosis when adjusted. No incidence of HIV infection was detected. CONCLUSIONS: This retrospective cohort analysis showed that TDF-FTC offered superior PrEP protection. Although high PrEP adherence ensured protection from HIV infection, it was significantly associated with a higher risk of developing osteopenia/osteoporosis. These findings suggest that routine check-ups for osteopenia/osteoporosis may be needed.

Prevalence of anti-SARS-CoV-2 antibodies and associated factors in healthcare workers of a Mexican Covid-19 hospital

OBJECTIVE: To determine the prevalence of SARS-CoV-2 antibodies among healthcare workers (HCW) and to identify factors associated with infection. Materials and meth-ods. A cross-sectional study was conducted in a Covid-19 hospital in Morelos, Mexico. Antibodies against SARS-CoV-2 spike and nucleocapsid proteins were detected by ELISA. A bivariate and multivariable Poisson regression model were performed to identify factors associated with infection. RESULTS: Among all participants, 31% had anti-SARS-CoV-2 antibodies, while only 13.1% had reported a history of positive RT-PCR. Individuals who reported cohabiting with someone with Covid-19, and those who had a previous RT-PCR test, were more likely to be seropositive. Laboratory personnel had the lowest seroprevalence (12.0%), while social workers had the highest (35.7%). CONCLUSIONS: The results of this study show the seroprevalence of SARS-CoV-2 antibodies among HCW in a hospital in Mexico, and underline the importance of serological tests for a better estimate of prevalence in health systems where only symptomatic cases are recorded.

Implementing California Senate Bill 493 in an Outpatient Pharmacy Within an Integrated Health System: Evaluation of the Operational and Clinical Effect of Pharmacist-Ordered Laboratory Tests.

BACKGROUND: Under California Senate Bill 493, pharmacists can order patient laboratory tests (labs). Currently, it is unknown if this service affects patient outcomes or pharmacy operations. Does lab ordering by pharmacists improve access to care, improve quality outcomes, and/or affect pharmacy operational functions? PROGRAM DESCRIPTION: A 13-month pilot study was conducted at 2 Kaiser Permanente (KP) outpatient pharmacies where pharmacists provided extended adherence consultations and ordered hemoglobin A1c (HbA1c) labs for patients nonadherent to their oral diabetic medications with an HbA1c ≥ 8% or missing annual labs. Clinical outcomes of the pilot study were compared with a similar patient population at KP who concurrently received lab orders from their primary providers, defined here as the "usual care model." OBSERVATION: Of the 793 HbA1c lab orders, 87 (11.0%) were generated by a pharmacist, and 706 (89.0%) were generated by the usual care group. Forty-three (49.4%) patients in the pharmacist group completed their labs compared with 279 (39.5%) patients in the usual care group (P = 0.10). A significantly greater proportion of patients in the pharmacist group achieved an HbA1c < 8% within the follow-up period of 30-180 days (34.9%), compared with the usual care group (12.2%, P < 0.01). Of the patients who completed labs during the evaluation period, 38 (43.7%) patients in the pharmacist group and 111 (15.7%) patients in the usual care group had prelaboratory values ≥ 8% within the previous 12 months. The average pre-HbA1c value was 9.47% in the pharmacist group, and the average post-HbA1c value was 8.68% (P < 0.01). For the usual care group, the average pre-HbA1c value was 9.70%, and the average post-HbA1c value was 9.43% (P = 0.06). When comparing the difference in HbA1c reduction between the 2 groups, there was a larger decrease in HbA1c in the pharmacist group, but this difference was not significantly different (P = 0.06). The pilot study added an average of 5 minutes per patient encounter to the pharmacy workflow but did not affect overall patient wait times for receiving outpatient prescriptions. IMPLICATIONS: Laboratory ordering by pharmacists in the outpatient setting improved access to care, improved quality outcomes, and did not adversely affect pharmacy operations. DISCLOSURES: No outside funding supported this project. The authors have nothing to disclose.

Stereotactic body radiation therapy and minimally invasive surgery in the management of spinal metastases: a change in the paradigm. / Radioterapia estreotáxica corporal y cirugía mínimamente invasiva en el manejo de las metástasis espinales: un cambio de paradigma.

The main goal of treatment in spinal metastatic patients is local control of the disease, pain relief and the maintenance of ambulation. Traditionally, wide surgical resection of the tumour followed by adjuvant radiation and/or chemotherapy has been recommended. Currently, single-fraction or hypofractionated stereotactic body radiation therapy (SBRT) yields a one-year local control rate of over 95% with minimum morbidity, even for tumours previously considered radioresistant. In addition, by posterolateral and circumferential decompression and stabilisation of the spinal cord, it is feasible to create a 2 to 3 mm epidural margin between the dura mater and the tumour (separation surgery), enough to deliver safe and ablative doses of SBRT to the vertebrae. As these patients tend to be frail, such interventions should ideally be minimally invasive, thereby reducing surgical aggressiveness and helping to minimise the delay of any systemic therapies.

Direct cortical stimulation with cylindrical depth electrodes in the interhemispheric fissure for leg motor evoked potential monitoring.

OBJECTIVE: To evaluate cylindrical depth electrodes in the interhemispheric fissure as an alternative to subdural strip electrodes for direct cortical stimulation (DCS) leg motor evoked potential (MEP) monitoring. METHODS: A cylindrical depth electrode was positioned in the interhemispheric fissure of 37 patients who underwent supratentorial brain surgery. Leg sensory and motor cortices were localized by highest tibial nerve somatosensory evoked potential amplitude and lowest DCS leg MEP threshold; the lowest-threshold electrode was then used for DCS leg MEP monitoring. RESULTS: Intraoperative leg MEPs were obtained from all the patients in the series. The mean intensity applied for leg MEP monitoring with the cylindrical depth electrode was 15.2 ± 4.0 mA. No complications secondary to neurophysiological monitoring were detected. CONCLUSIONS: Lower extremity MEPs were consistently recorded using a multi-contact cylindrical depth electrode in the interhemispheric fissure by DCS. SIGNIFICANCE: Cylindrical depth electrodes may be a safe and effective alternative for DCS in the interhemispheric fissure, where subdural strips are difficult to place.

Symposium review: Real-time continuous decision making using big data on dairy farms.

We are developing a real-time, data-integrated, data-driven, continuous decision-making engine, The Dairy Brain, by applying precision farming, big data analytics, and the Internet of Things. This is a transdisciplinary research and extension project that engages multidisciplinary scientists, dairy farmers, and industry professionals. Dairy farms have embraced large and diverse technological innovations such as sensors and robotic systems, and procured vast amounts of constant data streams, but they have not been able to integrate all this information effectively to improve whole-farm decision making. Consequently, the effects of all this new smart dairy farming are not being fully realized. It is imperative to develop a system that can collect, integrate, manage, and analyze on- and off-farm data in real time for practical and relevant actions. We are using the state-of-the-art database management system from the University of Wisconsin-Madison Center for High Throughput Computing to develop our Agricultural Data Hub that connects and analyzes cow and herd data on a permanent basis. This involves cleaning and normalizing the data as well as allowing data retrieval on demand. We illustrate our Dairy Brain concept with 3 practical applications: (1) nutritional grouping that provides a more accurate diet to lactating cows by automatically allocating cows to pens according to their nutritional requirements aggregating and analyzing data streams from management, feed, Dairy Herd Improvement (DHI), and milking parlor records; (2) early risk detection of clinical mastitis (CM) that identifies first-lactation cows under risk of developing CM by analyzing integrated data from genetic, management, and DHI records; and (3) predicting CM onset that recognizes cows at higher risk of contracting CM, by continuously integrating and analyzing data from management and the milking parlor. We demonstrate with these applications that it is possible to develop integrated continuous decision-support tools that could potentially reduce diet costs by $99/cow per yr and that it is possible to provide a new dimension for monitoring health events by identifying cows at higher risk of CM and by detecting 90% of CM cases a few milkings before disease onset. We are securely advancing toward our overarching goal of developing our Dairy Brain. This is an ongoing innovative project that is anticipated to transform how dairy farms operate.

Short communication: Use of the Clegg hammer measure as an indicator of stall-surface compressibility in tie-stall housing and its relationship with stall comfort.

Stall base and stall surface (i.e., with or without bedding) are key risk factors in cow comfort in dairy herds. In Canada, rubber mats, concrete floors, and mattresses are the most common stall bases used in tie-stall systems. Straw, wood shavings, and sand, at variable depths, are the most commonly used type of bedding. The Clegg hammer (Clegg Impact Soil Tester Hammer; Lafayette Instrument Company, Lafayette, IN) is a tool used by engineers to test the compressibility of pavement or golf course surfaces. Recently, this tool has also been used to measure the compressibility of the stall surface on freestall dairy farms. A total of 32 tie-stall dairy herds were selected in Québec to test the usefulness of the Clegg hammer as a tool to assess stall surface compressibility in tie-stall housing. This study had 2 main objectives: (1) identify the location and the number of measurements needed to obtain a stable indicator of compressibility, and (2) identify differences in the compressibility of the stall surface depending on the stall base and bedding depth. On each farm, we tested the compressibility of 10 stalls. No significant differences were found between the front and the back of the stall for the location of the Clegg hammer measures. The differences in readings of the Clegg hammer were nonsignificant after the third measure taken at the same location, meaning that 3 measures are sufficient at one location to obtain a compressibility measure. Significant differences were found among the different stall base and surface combinations tested. Rubber mats were less compressible than mattresses. When a large quantity of bedding (>7.5 cm) was added on top of rubber mats, the compressibility results were equal to those of mattresses ≥10 yr old without bedding. To appropriately test the compressibility of stall surface in tie-stall farms, we recommend measuring the compressibility of the stall base on its own and with the usual amount of bedding used on the farm. Our study establishes that both stall base and surface affect compressibility, and that a large quantity of bedding helps increase the compressibility of the bed, especially on a harder stall base.

Laws limiting the prescribing or dispensing of opioids for acute pain in the United States: A national systematic legal review.

BACKGROUND: Opioid overdose is a continuing public health crisis. In response to an increasing recognition of the negative outcomes sometimes associated with the use of opioid analgesics, states have taken a number of steps attempting to reduce inappropriate prescribing of these medications. These include the imposition of strict legal limitations on the amount or duration that opioid analgesics may be prescribed or dispensed to patients with acute pain. METHODS: We conducted a systematic, multi-source legal review of state laws that impose mandatory limits on the ability of medical professionals to prescribe or dispense opioids for the treatment of acute pain. We also systematically searched for and examined publicly available documents on state legislative and regulatory bodies' websites. All relevant laws were downloaded and systematically coded. RESULTS: By the end of 2017, twenty-six states had passed laws that impose mandatory limits on the prescribing or dispensing of opioids for acute pain. The oldest of these laws became effective as early as 1989, but most are much newer: approximately 65% (17/26) were passed in 2017. There is wide variation in the characteristics of these laws. CONCLUSION: Just over half of all states have enacted laws that restrict the prescribing or dispensing of opioids for acute pain. To date, there is no data on whether and to what extent these laws mediate opioid-related morbidity and mortality, as well as whether they are associated with negative unintended outcomes. Research into these questions is urgently needed.

Declaración de Cali / Cali Statement

Las Ministras y Ministros participantes en la VII Cumbre Iberoamericana de Medicina Familiar, realizada en Cali, Colombia, con el objetivo de reflexionar sobre el papel de la Medicina Familiar en los Sistemas de Salud basados en Atención Primaria, y específicamente en la atención de situaciones complejas de las personas, las familias y las comunidades como centro de estos Sistemas:

The Ministers participating in the VII Ibero-American Summit of Family Medicine, held in Cali, Colombia, with the aim of reflecting on the role of Family Medicine in Health Systems based on Primary Care, and specifically on the care of complex situations of people, families and communities as the centre of these Systems:

Marginal structural Cox model to estimate the causal effect of clinical mastitis on Québec dairy cow culling risk.

Health disorders, such as milk fever, displaced abomasum, or retained placenta, as well as poor reproductive performance, are known risk factors for culling in dairy cows. Clinical mastitis (CM) is one of the most influential culling risk factors. However the culling decision could be based either on the disease status or on the current milk yield, milk production being a significant confounder when modelling dairy cow culling risk. But milk yield (and somatic cell count) are time-varying confounders, which are also affected by prior CM and therefore lie on the causal pathway between the exposure of interest, CM, and the outcome, culling. Including these time-varying confounders could result in biased estimates. A marginal structural model (MSM) is a statistical technique allowing estimation of the causal effect of a time-varying exposure in the presence of time-varying covariates without conditioning on these covariates. The objective of this paper is to estimate the causal effect on culling of CM occurring between calving and 120 days in milk, using MSM to control for such time-varying confounders affected by previous exposure. A retrospective longitudinal study was conducted on data from dairy herds in the Province of Québec, Canada, by extracting health information events from the dairy herd health management software used by most Québec dairy producers and their veterinarians. The data were extracted for all lactations starting between January 1st and December 31st, 2010. A total of 3952 heifers and 8724 cows from 261 herds met the inclusion criteria and were used in the analysis. The estimated CM causal hazard ratios were 1.96 [1.57-2.44] and 1.47 [1.28-1.69] for heifers and cows, respectively, and as long as causal assumptions hold. Our findings confirm that CM was a risk factor for culling, but with a reduced effect compared to previous studies, which did not properly control for the presence of time-dependent confounders such as milk yield and somatic cell count. Cows experienced a lower risk for CM, with milk production having more influence on culling risk in cows than heifers.

Culling from the herd's perspective-Exploring herd-level management factors and culling rates in Québec dairy herds.

The relationship between cows' health, reproductive performance or disorders and their longevity is well demonstrated in the literature. However these associations at the cow level might not hold true at the herd level, and herd-level variables can modify cow-level outcomes independently of the cows' characteristics. The interaction between cow-level and herd-level variables is a relevant issue for understanding the culling of dairy cows. However it requires the appropriate group-level variables to assess any contextual effect. Based on 10 years of health and production data, the objectives of this paper are:(a) to quantify the culling rates of dairy herds in Québec; (b) to determine the profiles of the herds based on herd-level factors, such as demographics, reproduction, production and health indicators, and whether these profiles can be related to herd culling rates for use as potential contextual variables in multilevel modelling of culling risk. A retrospective longitudinal study was conducted on data from dairy herds in Québec, Canada, by extracting health information events from the dairy herd health management software used by most Québec producers and their veterinarians. Data were extracted for all lactations taking place between January 1st, 2001 and December 31st, 2010. A total of 432,733 lactations from 156,409 cows out of 763 herds were available for analysis. Thirty cow-level variables were aggregated for each herd and years of follow-up, and their relationship was investigated by Multiple Factor Analysis (MFA). The overall annual culling rate was 32%, with a 95% confidence interval (CI) of [31.6%,32.5%]. The dairy sale rate by 60 days in milk (DIM) was 3.2% [2.8%,3.6%]. The annual culling rate within 60 DIM was 8.2% [7.9%,8.4%]. The explained variance for each axis from the MFA was very low: 14.8% for the first axis and 13.1% for the second. From the MFA results, we conclude there is no relationship between the groups of herd-level indicators, demonstrating the heterogeneity among herds for their demographics, reproduction and production performance, and health status. However, based on Principal Component Analysis (PCA), the profiles of herds could be determined according to specific, single, herd-level indicators independently. The relationships between culling rates and specific herd-level variables within factors were limited to livestock sales, proportion of first lactation cows, herd size, proportion of calvings occurring in the fall, longer calving intervals and reduced 21-day pregnancy rates, increased days to first service, average age at first calving, and reduced milk fever incidence. The indicators found could be considered as contextual variables in multilevel model-building strategies to investigate cow culling risk.

Contextual herd factors associated with cow culling risk in Québec dairy herds: A multilevel analysis.

Several health disorders, such as milk fever, displaced abomasum, and mastitis, as well as impaired reproductive performance, are known risk factors for the removal of affected cows from a dairy herd. While cow-level risk factors are well documented in the literature, herd-level associations have been less frequently investigated. The objective of this study was to investigate the effect of cow- and herd-level determinants on variations in culling risk in Québec dairy herds: whether herd influences a cow's culling risk. For this, we assessed the influence of herd membership on cow culling risk according to displaced abomasum, milk fever, and retained placenta. A retrospective longitudinal study was conducted on data from dairy herds in the Province of Québec, Canada, by extracting health information events from the dairy herd health management software used by most Québec dairy producers and their veterinarians. Data were extracted for all lactations starting between January 1st and December 31st, 2010. Using multilevel logistic regression, we analysed a total of 10,529 cows from 201 herds that met the inclusion criteria. Milk fever and displaced abomasum were demonstrated to increase the cow culling risk. A minor general herd effect was found for the culling risk (i.e. an intra-class correlation of 1.0% and median odds ratio [MOR] of 1.20). The proportion of first lactation cows was responsible for this significant, but weak herd effect on individual cow culling risk, after taking into account the cow-level factors. On the other hand, the herd's average milk production was a protective factor. The planning and management of forthcoming replacement animals has to be taken into consideration when assessing cow culling risks and herd culling rates.

Electrical stimulation threshold in chronically compressed lumbar nerve roots: Observational study.

OBJECTIVES: Intraoperative neuromonitoring (IONM) is a common practice in spinal surgery, mostly during pedicle screw placement. However, there is not enough information about the factors that can interfere with IONM data. One of these factors may be existing damage of the nerve root whose function must be preserved. The main purpose of the present study is to evaluate the effect of chronic compression in lumbar nerve roots in terms of stimulation thresholds during direct nerve stimulation. PATIENTS AND METHODS: Direct electrical stimulation was performed in 201 lumbar nerve roots during lumbar spinal procedures under general anaesthesia in 80 patients with different lumbar spinal pathologies. Clinical and radiological data were reviewed in order to establish the presence of chronic compression. RESULTS: Chronically compressed nerve roots showed a higher stimulation threshold than non compressed nerve roots (11.93 mA vs. 4.33 mA). This difference was confirmed with intra-subject comparison (paired sample t test, p=0.012). No other clinical factors were associated with this higher stimulation threshold in lumbar nerve roots. CONCLUSION: A higher stimulation threshold is present in compressed lumbar nerve roots than non compressed roots. This needs to be taken into consideration during pedicle screw placement, where intraoperative neurophysiological monitoring is being used.