Wensheng Guo

Have we made progress in preventing shunt failure? A critical analysis.

OBJECT The goal of this study was to determine whether failure rates of hydrocephalus shunts have fallen over the years as a result of experience or technical improvements. METHODS A structured search was performed of the English language literature for case series reporting failure rates after shunt insertion. A metaanalytic model was constructed to pool data from multiple studies and to analyze failure rates statistically for temporal trends. Separate models were used for children (< 17 years old) and adults. RESULTS In children, the shunt failure rate was 31.3% for the 1st year and 4.5% per year thereafter. There were no significant changes in either rate over time. Although 1st-year failure rates in adults have fallen slightly over time, late failure rates have risen. CONCLUSIONS Progress in preventing shunt failures has not been made over the last several decades. Any improvements made in shunt materials or insertion techniques have been overshadowed by biological and other factors.

Prevalence of cervical spinal injury in trauma.

OBJECT Diagnosis of cervical spinal injury (CSI) is an essential aspect of the trauma evaluation. This task is especially difficult in patients who are not clinically able to be evaluated (unevaluable) because of distracting painful injuries, intoxication, or concomitant head injury. For this population, the appropriate use of advanced imaging techniques for cervical spinal clearance remains undetermined. This study was undertaken to estimate the prevalence of unstable CSI, particularly among patients in whom clinical evaluation is impossible or unreliable. METHODS Estimates of the prevalence of CSI in populations consisting of all trauma patients, alert patients only, and clinically unevaluable patients only were determined by variance-weighted pooling of data from 65 publications (281,864 patients) that met criteria for review. RESULTS The overall prevalence of CSI among all trauma patients was 3.7%. The prevalence of CSI in alert patients was 2.8%, whereas unevaluable patients were at increased risk of CSI with a prevalence of 7.7% (p = 0.007). Overall, 41.9% of all CSI cases were considered to exhibit instability. CONCLUSIONS Trauma patients who are clinically unevaluable have a higher prevalence of CSI than alert patients. Knowledge of the prevalence and risk of such injuries may help establish an evidence-based approach to the detection and management of clinically occult CSI.

The Effect of Post-injury Depression on Return to Pre-injury Function: a Prospective Cohort Study

BACKGROUND Millions of people seek emergency department (ED) care for injuries each year, the majority for minor injuries. Little is known about the effect of psychiatric co-morbid disorders that emerge after minor injury on functional recovery. This study examined the effect of post-injury depression on return to pre-injury levels of function. METHOD This was a longitudinal cohort study with follow-up at 3, 6 and 12 months post-injury: 275 adults were randomly selected from those presenting to the ED with minor injury; 248 were retained over the post-injury year. Function was measured with the Functional Status Questionnaire (FSQ). Psychiatric disorders were diagnosed using the Structured Clinical Interview for DSM-IV-TR disorders (SCID). RESULTS During the post-injury year, 18.1% [95% confidence interval (CI) 13.3-22.9] were diagnosed with depression. Adjusting for clinical and demographic covariates, the depressed group was less likely to return to pre-injury levels of activities of daily living [odds ratio (OR) 8.37, 95% CI 3.78-18.53] and instrumental activities of daily living (OR 3.25, 95% CI 1.44-7.31), less likely to return to pre-injury work status (OR 2.37, 95% CI 1.04-5.38), and more likely to spend days in bed because of health (OR 2.41, 95% CI 1.15-5.07). CONCLUSIONS Depression was the most frequent psychiatric diagnosis in the year after minor injury requiring emergency care. Individuals with depression did not return to pre-injury levels of function during the post-injury year.

Mapping activity patterns to quantify risk of violent assault in urban environments

Background: We collected detailed activity paths of urban youth to investigate the dynamic interplay between their lived experiences, time spent in different environments, and risk of violent assault. Methods: We mapped activity paths of 10- to 24-year-olds, including 143 assault patients shot with a firearm, 206 assault patients injured with other types of weapons, and 283 community controls, creating a step-by-step mapped record of how, when, where, and with whom they spent time over a full day from waking up until going to bed or being assaulted. Case–control analyses compared cases with time-matched controls to identify risk factors for assault. Case-crossover analyses compared cases at the time of assault with themselves earlier in the day to investigate whether exposure increases acted to the trigger assault. Results: Gunshot assault risks included being alone (odds ratio [OR] = 1.6, 95% confidence interval [CI] = 1.3, 1.9) and were lower in areas with high neighbor connectedness (OR = 0.7, 95% CI = 0.6, 0.8). Acquiring a gun (OR = 1.4, 95% CI = 1.1, 1.6) and entering areas with more vacancy, violence, and vandalism (OR = 1.7, 95% CI = 1.1, 2.7) appeared to trigger the risk of getting shot shortly thereafter. Nongunshot assault risks included being in areas with recreation centers (OR = 1.2, 95% CI = 1.1, 1.4). Entering an area with higher truancy (OR = 1.6, 95% CI = 1.1, 2.5) and more vacancy, violence, and vandalism appeared to trigger the risk of nongunshot assault. Risks varied by age group. Conclusions: We achieved a large-scale study of the activities of many boys, adolescents, and young men that systematically documented their experiences and empirically quantified risks for violence. Working at a temporal and spatial scale that is relevant to the dynamics of this phenomenon gave novel insights into triggers for violent assault.

A mathematical model of survival in a newly inserted ventricular shunt

OBJECT The object of this study was to mathematically model the prognosis of a newly inserted shunt in pediatric or adult patients with hydrocephalus. METHODS A structured search was performed of the English-language literature for case series reporting shunt failure, patient mortality, and shunt removal rates after shunt insertion. A metaanalytic model was constructed to pool data from multiple studies and to predict the outcome of a shunt after insertion. Separate models were used to predict shunt survival rates for children (patients < 17 years old) and adults. RESULTS Shunt survival rates in children and adults were calculated for 1 year (64.2 and 80.1%, respectively), 5 years (49.4 and 60.2%, respectively), and the median (4.9 and 7.3 years, respectively). The longer-term rates predicted by the model agree closely with those reported in the literature. CONCLUSIONS This model gives a comprehensive view of the fate of a shunt for hydrocephalus after insertion. The advantages of this model compared with Kaplan-Meier survival curves are discussed. The model used in this study may provide useful prognostic information and aid in the early evaluation of new shunt designs and techniques.

Vacant Properties and Violence in Neighborhoods

OBJECTIVES Violence remains a significant public health issue in the United States. To determine if urban vacant properties were associated with an increased risk of assaultive violence and if this association was modified by important neighborhood institutions (e.g., schools, parks/playgrounds, police stations, and alcohol outlets). METHODS Longitudinal ecologic study of all 1816 block groups in Philadelphia. Aggravated assault and vacant property data were compiled yearly from 2002 to 2006 and linked to block groups. A mixed effects negative binomial regression model examined the association of vacant properties and assaults between and within block groups. RESULTS Among all block groups, 84% experienced at least one vacant property, 89% at least one aggravated assault, and 64% at least one gun assault. Between block groups, the risk of aggravated assault increased 18% for every category shift of vacant properties (IRR 1.18, 95% CI: 1.12, 1.25, P < 0.001). Parks/playgrounds and alcohol outlets potentially modified the association between vacant properties and aggravated assaults but only at low levels of vacancy. CONCLUSIONS Increasing levels of vacancy were associated with increased risk of assaultive violence in urban block groups.

Fears of violence during morning travel to school

PURPOSE Childrens safety as they travel to school is a concern nationwide. We investigated how safe children felt from the risk of being assaulted during morning travel to school. METHODS Children between 10 and 18 years old were recruited in Philadelphia and interviewed with the aid of geographic information system (GIS) mapping software about a recent trip to school, situational characteristics, and how safe they felt as they travelled based on a 10-point item (1 = very unsafe, 10 = very safe). Ordinal regression was used to estimate the probability of perceiving different levels of safety based on transportation mode, companion type, and neighborhood characteristics. RESULTS Among 65 randomly selected subjects, routes to school ranged from 7 to 177 minutes (median = 36) and .1-15.1 street miles (median = 1.9), and included between 1-5 transportation modes (median = 2). Among students interviewed, 58.5% felt less than very safe (i.e., <10) at some point while traveling to school and one-third (32.5%) of the total person time was spent feeling less than very safe. Nearly a quarter of students, or 24.6%, felt a reduction in safety immediately upon exiting their home. The probability of reporting a safety of >8, for example, was .99 while in a car and .94 while on foot but was .86 and .87 when on a public bus or trolley. Probability was .98 while with an adult but was .72 while with another child and .71 when alone. Also, perceived safety was lower in areas of high crime and high density of off-premise alcohol outlets. CONCLUSIONS Efforts that target situational risk factors are warranted to help children feel safe over their entire travel routes to school.

The prevalence of shunt-treated hydrocephalus: a mathematical model.

BACKGROUND The aim of the study was to create a mathematical model that reproduces the prevalence of shunt-treated hydrocephalus in the United States over the years and predicts trends in the near future. METHODS A structured search was performed of the English language literature for case series reporting rates of shunt insertion and revision, shunt removal, and patient mortality. A meta-analytic model was constructed to pool data from multiple studies and to calculate these rates at various time intervals. Separate Markov models were used to predict numbers of shunts at any one time for children (<17 years old) and adults. The models analyze the number of shunts inserted every year since 1955 and follow the likely fates of those patients as time passes. RESULTS Prevalence rates predicted by the model agree closely with those reported in the literature. However, the models structure creates considerable variability around point estimates. CONCLUSIONS The model gives a comprehensive view of the prevalence of shunt-treated hydrocephalus in both children and adults from 1955 to the present. This model may prove useful in predicting resource use and needs for patients with hydrocephalus.

Comparing residence-based to actual path-based methods for defining adolescents’ environmental exposures using granular spatial data

&NA; This paper uses data from a population‐based case control study of daily activities and assault injury to examine residence‐based versus actual path‐based approaches to measuring environmental exposures that pose risks for violence among adolescents. Defining environmental exposures based on participant home address resulted in significant misclassification compared to gold standard daily travel path measures. Dividing participant daily travel paths into origin‐destination segments, we explore a method for defining spatial counterfactuals by comparing actual trip path exposures to shortest potential trip path exposures. Spatial methods explored herein can be utilized in future research to more accurately quantify environmental exposures and associations with health outcomes. HighlightsExamines residence vs. path‐based approaches to measure environmental violence risks.Home address resulted in significant misclassification compared to daily paths.Trip path analyses provided a method for generating spatial counterfactuals.Proposed actual path‐based methods can be applied to future injury research.

Adult Connection in Assault Injury Prevention among Male Youth in Low-Resource Urban Environments

Strengths-based strategies to reduce youth violence in low-resource urban communities are urgently needed. Supportive adolescent-adult relationships may confer protection, but studies have been limited by self-reported composite outcomes. We conducted a population-based case-control study among 10- to 24-year-old males in low-resource neighborhoods to examine associations between supportive adult connection and severe assault injury. Cases were victims of gunshot assault injury (n = 143) and non-gun assault injury (n = 206) from two level I trauma centers. Age- and race-matched controls (n = 283) were recruited using random digit dial from the same catchment. Adolescent-adult connections were defined by: (1) brief survey questions and (2) detailed family genograms. Analysis used conditional logistic regression. There were no significant associations between positive adult connection, as defined by brief survey questions, and either gunshot or non-gun assault injury among adolescents with high prior violence involvement (GSW OR = 2.46, 95% CI 0.81–7.49; non-gun OR = 1.59, 95% CI 0.54–4.67) or low prior violence involvement (GSW OR = 0.92, 95% CI 0.34–2.44; non-gun OR = 1.96, 95% CI 0.73–5.28). In contrast, among adolescents with high levels of prior violence involvement, reporting at least one supportive adult family member in the family genogram was associated with higher odds of gunshot assault injury (OR = 4.01, 95% CI 1.36–11.80) and non-gun assault injury (OR = 4.22, 95% CI 1.48–12.04). We were thus unable to demonstrate that positive adult connections protected adolescent males from severe assault injury in this highly under-resourced environment. However, at the time of injury, assault-injured adolescents, particularly those with high prior violence involvement, reported high levels of family support. The post-injury period may provide opportunities to intervene to enhance and leverage family connections to explore how to better safeguard adolescents.