Injured Cohort Research Articles

Adaptation of motor function after spinal cord injury: novel insights into spinal shock

The mechanisms underlying spinal shock have not been clearly defined. At present, clinical assessment remains the mainstay to describe progression through spinal shock following traumatic spinal cord injury. However, nerve excitability studies in combination with conventional nerve conduction and clinical assessments have the potential to investigate spinal shock at the level of the peripheral axon. Therefore, peripheral motor axon excitability was prospectively and systematically evaluated in more than 400 studies of 11 patients admitted to hospital after traumatic spinal cord injury, with cord lesions above T9 (nine cervical, two thoracic). Recordings commenced within 15 days of admission from the median nerve to abductor pollicis brevis in the upper limb and the common peroneal nerve to tibialis anterior in both lower limbs, and were continued until patient discharge from hospital. Excitability was assessed using threshold tracking techniques and recordings were compared with data from healthy controls. In addition, concurrent clinical measures of strength, serum electrolytes and nerve conduction were collected. High threshold stimulus-response relationships were apparent from the early phase of spinal shock that coincided with depolarization-like features that reached a peak on Day 16.9 (± 2.7 standard error) for the common peroneal nerve and Day 11.8 (± 2.0 standard error) for the median nerve. Overall, changes in the common peroneal nerve were of greater magnitude than for the median nerve. For both nerves, the most significant changes were in threshold electrotonus, which was 'fanned in', and during the recovery cycle superexcitability was reduced (P < 0.001). However, refractoriness was increased only for the common peroneal nerve (P < 0.05). Changes in the spinal injured cohort could not be explained on the basis of an isolated common peroneal nerve palsy. By the time patients with spinal injury were discharged from hospital between Days 68 and 215, excitability for upper and lower limbs had returned towards normative values, but not for all parameters. Electrolyte levels and results for nerve conduction studies remained within normal limits throughout the period of admission. Contrary to prevailing opinion, these data demonstrate that significant changes in peripheral motor axonal excitability occur early during spinal shock, with subsequent further deterioration in axonal function, before recovery ensues.

Noxious Colorectal Distention in Spinalized Rats Reduces Pseudorabies Virus Labeling of Sympathetic Neurons

The retrograde transsynaptic tracer pseudorabies virus (PRV) has been widely used as a marker for synaptic connectivity in the spinal cord. Notably, the PRV-152 construct expresses enhanced green fluorescent protein (EGFP). We recently reported a significant attenuation of PRV-152 labeling of the intermediolateral cell column (IML) and celiac ganglia after complete T4 spinal cord transection versus sham injury in rats at 96 h after PRV-152 inoculation of the left kidney. Here we found a significant increase in noxious colorectal distention (CRD)-evoked c-Fos expression in spinal cords of injured versus sham rats without PRV infection. In order to assess whether enhancing neuronal activity in spinalized rats might increase PRV-152 labeling, we subjected awake spinalized rats to 1.5 h of intermittent noxious CRD either: (1) just prior to inoculation, or (2) 96 h after inoculation (n = 3/group). Equal numbers of spinalized rats in both groups received PRV-152 inoculations without CRD (non-stimulated; n = 3/group). At 96 h post-inoculation fixed spinal cords and left celiac ganglionic tissues were assessed for the distribution and quantification of EGFP-labeled cells. The injured cohort that received CRD just prior to PRV injection showed a significant reduction in EGFP-labeled cells in both the IML and left celiac ganglion compared to non-stimulated injured rats. In contrast, the injured cohort that received CRD 96 h after PRV-152 inoculation showed no differences in EGFP-labeled cell numbers in the IML or celiac ganglia versus non-stimulated injured rats. Interestingly, microglia near c-Fos-positive cells after acute CRD appeared more reactive compared to non-stimulated spinalized rats, and activated microglial cells markedly reduce viral transduction and progression following PRV inoculation of the CNS. Hence our results imply that increased CRD-induced c-Fos expression in the injured paradigm, prior to but not after PRV injection, further attenuates PRV-152 uptake, perhaps through changes in neuronal activity and/or innate neuro-immune responses.

The incidence of scaphoid fracture in a military population

Background The rate of occurrence of scaphoid injury is not well known. The incidence of scaphoid fracture has been described mostly in small, injured cohort populations, which may underestimate its frequency. We studied the epidemiology of the scaphoid fracture using a large database in a military population. Patients and methods The Defense Medical Epidemiology Database (DMED), a comprehensive database which tracks medical care for all four military services of the United States, was queried for the first occurrence of scaphoid fractures using International Classification of Diseases (ICD)-9 code 814.01. Data were evaluated using multivariate Poisson analysis, controlling for co-variate factors. Results We noted 14,704 scaphoid fractures in a population at a risk of 12,117,749 person-years. The unadjusted incidence of scaphoid fracture was 1.21/1000 person-years. Males were significantly more likely to sustain scaphoid fractures, with an adjusted rate ratio (RR) of 1.55 (95% confidence interval (C.I.), 1.47, 1.64), compared to females. The 20–24-year-old age group had the highest incidence of scaphoid fracture at 1.64/1000 person-years, and showed a significantly higher RR compared to the population aged greater than 40 years (adjusted RR 1.55, 95% C.I., 1.38, 1.66). Whites sustained scaphoid fractures at a significantly higher rate than African Americans (adjusted RR 1.32, C.I., 1.26, 1.38). Discussion/conclusions When compared to the previous data on scaphoid fractures, our study showed a greater incidence of scaphoid fracture at 1.21/1000 person-years in the US military population. These data are derived from a large database which effectively captures the population at risk. Males, the younger age group and the white race were associated with higher rates of scaphoid injury in this specialised military population.

Long-Term Effects of Iatrogenic Bile Duct Injury During Cholecystectomy

The aim of this study was to study survival, factors influencing survival, and causes of death after iatrogenic reconstructed bile duct injury in a large population-based Swedish cohort. Patients who underwent cholecystectomy in the period from 1965 to 2005 were identified from the Swedish Inpatient Register. The bile duct injury cohort consisted of patients with procedure codes indicating reconstructive biliary surgery within 1 year of the cholecystectomy, excluding patients with reconstruction owing to other causes than bile duct injury. Of 374,042 cholecystectomy patients, 1386 were classified as afflicted by bile duct injury requiring reconstructive surgery. Survival was significantly lower in the injured cohort compared with the noninjured cohort, with a hazard ratio of 3.73 (95% confidence interval, 3.30-4.22) at 1 year that gradually evened out thereafter. The risk of dying from liver diseases was increased 4-fold in the bile duct injury cohort compared with the general population. Older age and comorbidity increased the risk of dying, whereas the use of intraoperative cholangiogram improved survival. Patients with iatrogenic reconstructed bile duct injury have a decreased survival rate compared with noninjured cholecystectomy patients. Patients' younger age, absence of other diseases, and routine use of intraoperative cholangiogram seem to be positive prognostic survival factors. These patients also may be at increased risk of dying from liver diseases, although this issue requires further study.

Population health and clinical data linkage: the importance of a population registry

The Australian National Collaborative Research Infrastructure Strategy supports development of a national research capability in population health and clinical data linkage. This paper illustrates the importance of incorporating a population registry within such a system using an example provided by the Manitoba Injury Outcome Study (MIOS) that quantified the long-term burden of mortality attributable to injury in working-age adults. MIOS is a population-based matched cohort study that used administrative health data from Manitoba, Canada. An inception cohort of injured cases (ICD-9-CM 800-995) aged 18-64 years was identified from all Manitoba hospital admissions between 1988 and 1991. A matched non-injured comparison group was randomly selected from the total provincial population using the Manitoba Population Registry. Mortality outcomes were obtained by linking the two cohorts with the deaths data over 10 years. Mortality rate ratios (MRRs) were calculated to compare the injured and non-injured cohorts. A total of 21,032 matched pairs were identified. Using the population registry, the 10-year adjusted all-cause MRR comparing injured and non-injured cohort was 1.80 (95% CI 1.65-1.98). Without the registry, the unadjusted standardised morality ratio was 2.76 (95% CI 2.52-3.02). The effect of injury on mortality outcomes was over-estimated using only the injured cases, without use of the population registry. Use of the population registry enabled the selection of a matched non-injured group for comparison purposes, ensured comprehensive follow-up of almost all participants, and provided more accurate estimates of exposure time, incidence of mortality and relative risk.

Ten-year health service use outcomes in a population-based cohort of 21 000 injured adults: the Manitoba Injury Outcome Study

To quantify long-term health service use (HSU) following non-fatal injury in adults. A retrospective, population-based, matched cohort study identified an inception cohort (1988-91) of injured people who had been hospitalized (ICD-9-CM 800-995) aged 18-64 years (n = 21 032) and a matched non-injured comparison group (n = 21 032) from linked administrative data from Manitoba, Canada. HSU data (on hospitalizations, cumulative length of stay, physician claims and placements in extended care services) were obtained for the 12 months before and 10 years after the injury. Negative binomial and Poisson regressions were used to quantify associations between injury and long-term HSU. Statistically significant differences in the rates of HSU existed between the injured and non-injured cohorts for the pre-injury year and every year of the follow-up period. After controlling for pre-injury HSU, the attributable risk percentage indicated that 38.7% of all post-injury hospitalizations (n = 25 183), 68.9% of all years spent in hospital (n = 1031), 21.9% of physician claims (n = 269 318) and 77.1% of the care home placements (n = 189) in the injured cohort could be attributed to being injured. Many people who survive the initial period following injury, face long periods of inpatient care (and frequent readmissions), high levels of contact with physicians and an increased risk of premature placement in institutional care. Population estimates of the burden of injury could be refined by including long-term non-fatal health consequences and controlling for the effect of pre-injury comorbidity.

Mental health: A cause or consequence of injury? A population-based matched cohort study

BackgroundWhile a number of studies report high prevalence of mental health problems among injured people, the temporal relationship between injury and mental health service use has not been established. This study aimed to quantify this relationship using 10 years of follow-up on a population-based cohort of hospitalised injured adults.MethodsThe Manitoba Injury Outcome Study is a retrospective population-based matched cohort study that utilised linked administrative data from Manitoba, Canada, to identify an inception cohort (1988–1991) of hospitalised injured cases (ICD-9-CM 800–995) aged 18–64 years (n = 21,032), which was matched to a non-injured population-based comparison group (n = 21,032). Pre-injury comorbidity and post-injury mental health data were obtained from hospital and physician claims records. Negative Binomial regression was used to estimate adjusted rate ratios (RRs) to measure associations between injury and mental health service use.ResultsStatistically significant differences in the rates of mental health service use were observed between the injured and non-injured, for the pre-injury year and every year of the follow-up period. The injured cohort had 6.56 times the rate of post-injury mental health hospitalisations (95% CI 5.87, 7.34) and 2.65 times the rate of post-injury mental health physician claims (95% CI 2.53, 2.77). Adjusting for comorbidities and pre-existing mental health service use reduced the hospitalisations RR to 3.24 (95% CI 2.92, 3.60) and the physician claims RR to 1.53 (95% CI 1.47, 1.59).ConclusionThese findings indicate the presence of pre-existing mental health conditions is a potential confounder when investigating injury as a risk factor for subsequent mental health problems. Collaboration with mental health professionals is important for injury prevention and care, with ongoing mental health support being a clearly indicated service need by injured people and their families. Public health policy relating to injury prevention and control needs to consider mental health strategies at the primary, secondary and tertiary level.

Long-Term Follow-Up (32 Years) of PTSD in Israeli Yom Kippur War Veterans

The Yom Kippur War came as a major shock to the confidence and stability of the national psyche in Israel, and it may be suggested that the incidence of associated psychological trauma at least in war veterans may be more profound and long-standing. Therefore, the aim of this study was to investigate the presence of PTSD in a naturalistic cohort of Yom Kippur veterans 32 years after the war managed for PTSD in a specialized unit during the war. Results indicated that of the 277 (20.9%) initial battle front-injured referred for evaluation who were diagnosed with PTSD, 32 years later only 19 war veterans were still suffering with PTSD (6.85% of the PTSD subpopulation or 1.43% of the original injured combat veteran cohort). Results from this long-term follow-up study indicate a low incidence of chronic symptomatology that may be accounted for by the nature of the initial care, follow-up, and subpopulation investigated.

Long-term mortality following trauma: 10 year follow-up in a population-based sample of injured adults.

The aim of the study was to quantify trauma-related mortality in injured adults over 10 years postinjury. A population-based matched cohort study used linked administrative data from Manitoba, Canada, to identify an inception cohort (1988-1991) of hospitalized trauma cases (ICD-9-CM 800-959.9) aged 18-64 years (n = 18,210) and a matched noninjured comparison group (n = 18,210). Mortality outcomes were obtained by linking the two cohorts with the Manitoba Population Registry for a period of 10 years postinjury. The adjusted all-cause mortality rate ratio (MRR) was 7.29 (95% CI 4.53-11.74) for the 60 days immediately postinjury. The MRRs ranged between 1.17 and 2.41 for the remainder of the 10 year follow-up period. The index injury was estimated to be responsible for 41% of all recorded deaths in the injured cohort. Estimates of the total mortality burden, based on the early inpatient period alone, substantially underestimates the true burden from injury.

Differences in prevalence of pre-existing morbidity between injured and non-injured populations.

To identify and examine differences in pre-existing morbidity between injured and non-injured population-based cohorts. Administrative health data from Manitoba, Canada, were used to select a population-based cohort of injured people and a sample of non-injured people matched on age, gender, aboriginal status and geographical location of residence at the date of injury. All individuals aged 18-64 years who had been hospitalized between 1988 and 1991 for injury (International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM) code 800-995) (n = 21 032), were identified from the Manitoba discharge database. The matched non-injured comparison group comprised individuals randomly selected 1:1 from the Manitoba population registry. Morbidity data for the 12 months prior to the date of the injury were obtained by linking the two cohorts with all hospital discharge records and physician claims. Compared to the non-injured group, injured people had higher Charlson Comorbidity Index scores, 1.9 times higher rates of hospital admissions and 1.7 times higher rates of physician claims in the year prior to the injury. Injured people had a rate of admissions to hospital for a mental health disorder 9.3 times higher, and physician claims for a mental health disorder 3.5 times higher, than that of non-injured people. These differences were all statistically significant (P < 0.001). Injured people were shown to differ from the general non-injured population in terms of pre-existing morbidity. Existing population estimates of the attributable burden of injury that are obtained by extrapolating from observed outcomes in samples of injured cases may overestimate the magnitude of the problem.

Effect of age on hospitalized machine-related farm injuries among the Saskatchewan farm population.

Machinery-related injuries are the leading cause of fatal and hospitalized injuries on Canadian farms. In Saskatchewan, the proportion of all farm injuries related to farm machinery exceeds that reported for all of Canada. This project examined the relationship between age and various factors associated with farm machine-related injuries in Saskatchewan. A retrospective review of hospital discharge data from the administrative data set of Saskatchewan Health was conducted using external cause of injury codes to identify cases of farm machinery injury that occurred in Saskatchewan during the period April 1, 1990, to March 31, 2000. Log linear estimates of association of various factors in four age groups were derived. There were 1,493 hospitalizations attributed to farm machinery-related injuries. Among the injured cohort, age was a predictor of the rate of injury. Significant association for nature of injury, mechanism of injury, and type of machine varied by age group. These data provide insights for a case-control study of farm machinery-related injuries with the objective of determining personal, environmental, and machine-related factors that are responsible for this serious public health issue.

Nonintracranial fatal firearm injuries in children: implications for treatment.

Understanding the injury characteristics of nonintracranial fatal (NIF) gunshot wounds in children treated in a statewide trauma system will help guide effective treatment strategies. This study was a retrospective analysis of children fatally injured with firearms. The review included demographic information, firearm injury characteristics, and outcome. The setting included trauma centers participating in a statewide trauma registry. Patients were all children (age < 18 years) treated in trauma centers for NIF gunshot wounds from January 1988 through December 2000. The main outcome measures were characteristics of fatal firearm injuries in children. Over the 13-year period, there were 1,954 children with firearm injuries including 368 (18.8%) children with fatal wounds. Of the fatally wounded children, 177 (48.1%) had no intracranial injury. The NIF injury population was 90.4% male, with a mean age of 14.9 years (range, <1-17 years) and an Injury Severity Score of 38.2 (range, 9-75). Over 95% of deaths in this group occurred within 24 hours of admission. Although injuries to the thorax were most common (78.5%), 48.6% of the NIF cohort had injuries to multiple body regions, including 31% with injuries in both the abdomen and thorax. Compared with all children wounded by firearms, NIF firearm injury patients had, on average, more body regions injured (1.6 vs. 1.1, p < 0.001) and a greater total number of injuries (6.0 vs. 3.5, p < 0.001). Patients with an NIF injury were more likely to suffer a major vascular injury (54.8% vs. 13.8%, p < 0.001), lung injury (56.5% vs. 12.9%, p < 0.001), or cardiac injury (44.6% vs. 4.6%, p < 0.001) than all children with a firearm injury. Most children who arrive at trauma centers alive and subsequently die from NIF firearm injuries do so rapidly from major vascular and thoracic injury. Almost half of these children have injuries to multiple body regions, further complicating management. Innovative, aggressive treatment approaches should be sought to improve survival in this extremely injured cohort of children.

Recurrent Trauma in Elderly Patients

Older patients (those aged > or = 70 years) who have experienced trauma have an increased risk of recurrent trauma. Demographic, medical, and functional factors are potential contributors to the risk of subsequent trauma among injured elderly patients. Retrospective follow-up study. Study participants were derived from the Longitudinal Study of Aging, an extension of the 1984 National Health Interview Survey focusing on persons who were aged 70 years and older in 1984. A cohort of elderly patients participating in the Longitudinal Study of Aging and hospitalized for injury in 1985 (n = 100) was identified using Medicare hospital discharge data. An uninjured cohort (n = 401) was also identified from the Longitudinal Study of Aging and matched for age (1 year) and sex. Risk of admission for trauma among the injured cohort compared with the uninjured cohort and associations between demographic, medical, and functional characteristics and trauma recurrence. Following adjustment for potential confounding factors, the injured cohort was 3.25 times more likely (95% confidence interval, 1.99-5.31) to be hospitalized for injury during the follow-up period compared with the uninjured cohort. Among the injured cohort, those at greatest risk of subsequent trauma included women and those with chronic medical conditions or functional impairments, the latter being the only factor independently associated with recurrence. Elderly patients who have experienced trauma are at increased risk of subsequent injury. Interventions to reduce the likelihood of trauma recurrence should focus on those with chronic illnesses and functional impairments.

Long-term survival in the elderly after trauma.

In the elderly, trauma has been associated with increased, long-term, all-cause mortality. Functional limitations secondary to injury may be responsible for the reduced survival rate. The objective of this study was to test this hypothesis using data from the Longitudinal Study of Aging (LSOA). The LSOA is an extension of the 1984 National Health Interview Survey, which focused on 7,527 persons who were 70 years and older in 1984. Using data from the LSOA, a cohort of elderly patients hospitalized for injury in 1985 (N = 102) was identified from Medicare hospital discharge data. An uninjured cohort (N = 408) was also identified using the LSOA and matched by age (within 1 year) and sex. Deaths in both cohorts were identified using the National Death Index. Hazard ratios (HRs) for mortality within 6 years subsequent to injury, adjusted for demographic, health status, and functional characteristics, were calculated. The injured cohort had a significantly reduced rate of survival compared with the uninjured cohort (HR = 1.5; 95% confidence interval [CI] 1.1-2.2), and this relationship persisted after adjusting for demographic and health characteristics (HR = 1.4; 95% CI 1.0-2.0). After additional adjustment for measures of functional decline, the association diminished (HR = 1.2; 95% CI 0.8-1.7). Functional decline remained a strong, independent factor for the risk of mortality. Trauma in the elderly has both an acute and long-term influence on mortality; the latter seems to be mediated through a decline in function resulting from the injury. This study suggests that strategies to return the elderly patient to preinjury functional status are of paramount importance. Future research should explore the impact of these interventions on long-term survival.

Injuries and Health Care Use in Women with Partners in Batterer Intervention Programs

Objective:To characterize injury frequency, injury patterns, and health care seeking behavior in women with intimate partners enrolled in batterer intervention programs. Methods: A standardized telephone interview was conducted on a sample of women with male partners enrolled in batterer intervention programs in four U.S. cities. Information on prior injuries and the utilization of health care services was sought. Results: Four hundred and eighty eight of the 648 women (75.3%) reported a history of prior injury as a result of abuse. Contusions were the most common injury. Of the women reporting contusions, 233 (51.4%) reported contusions as their only injuries. Another 220 women (48.6%) reported other injuries in addition to contusions. In the majority of cases (63.2%) the contusions were to multiple body parts. When the contusion involved only one anatomical region, it was mostly to the face. A total of 192 of the 488 injured women (39.3%) reported ever seeking medical care for injuries caused by their intimate partner. Twenty-three women (4.7% of the injured cohort or 3.5% of the total cohort) reported having ever been hospitalized for injuries sustained from abuse.

Safety knowledge and risk behaviour of injured and uninjured young skiers and snowboarders

Earlier studies of ski injury indicated that youths were at increased risk of injury, that males were most likely to injure the head or face, and that females were most likely to injure the knee. To obtain information about safety knowledge and risk behaviour that might contribute to injury among young skiers and snow-boarders. Survey of knowledge and behaviour in injured and noninjured cohorts. Blackcomb Mountain, Whistler, British Columbia. A total of 863 noninjured and 118 injured skiers and snowboarders aged five to 17 years using Blackcomb during 1993/94. Skier Knowledge Inventory Questionnaire. The injured cohort had less knowledge of the Skiers Responsibility Code. In both groups, almost half had had no lessons, 31% had had bindings adjusted by nonprofessionals and chair lift safety bars were used one ride in four by children age 13 to 17 years. The injuried cohort wore helmets slightly less often. Both groups regularly skied through the trees (60% to 70%), and one-thirds had skied on closed runs. Excessive speed was identified as the major cause of injury. Skiers did not recognize jumping as contributing to injury. Lack of knowledge of safety rules was more prevalent among the injured cohort. Skiing without due care - including skiing through tress, skiing on closed runs, skiing with excessive speed and jumping, particularly by snowboarders - were identified as potential causes of injury.