Radiculomeningomyelitis due to Halicephalobus gingivalis in a horse.

An adult horse was euthanatized following a clinical diagnosis of cauda equina neuritis. Significant gross postmortem and histopathologic findings were limited to the sacral spinal cord and cauda equina. The sacral spinal cord, meninges, and spinal nerve roots were expanded and partially effaced by sclerosing granulomatous inflammation with necrosis. The lesion contained numerous nematode larvae and fewer adults with a rhabditiform esophagus having a corpus, isthmus, and valved bulb. Female nematodes were amphidelphic and didelphic with reflexed ovaries. These morphologic features confirm Halicephalobus gingivalis as a novel cause of clinical signs in this case of cauda equina neuritis.

Single-blind randomised controlled trial of chemonucleolysis and manipulation in the treatment of symptomatic lumbar disc herniation.

This single-blind randomised clinical trial compared osteopathic manipulative treatment with chemonucleolysis (used as a control of known efficacy) for symptomatic lumbar disc herniation. Forty patients with sciatica due to this diagnosis (confirmed by imaging) were treated either by chemonucleolysis or manipulation. Outcomes (leg pain, back pain and self-reported disability) were measured at 2 weeks, 6 weeks and 12 months. The mean values for all outcomes improved in both groups. By 12 months, there was no statistically significant difference in outcome between the treatments, but manipulation produced a statistically significant greater improvement for back pain and disability in the first few weeks. A similar number from both groups required additional orthopaedic intervention; there were no serious complications. Crude cost analysis suggested an overall financial advantage from manipulation. Because osteopathic manipulation produced a 12-month outcome that was equivalent to chemonucleolysis, it can be considered as an option for the treatment of symptomatic lumbar disc herniation, at least in the absence of clear indications for surgery. Further study into the value of manipulation at a more acute stage is warranted.

Information and advice to patients with back pain can have a positive effect. A randomized controlled trial of a novel educational booklet in primary care.

STUDY DESIGN: A double-blind, randomized controlled trial of a novel educational booklet compared with a traditional booklet for patients seeking treatment in primary care for acute or recurrent low back pain. OBJECTIVE: To test the impact of a novel educational booklet on patients' beliefs about back pain and functional outcome. SUMMARY OF BACKGROUND DATA: The information and advice that health professionals give to patients may be important in health care intervention, but there is little scientific evidence of their effectiveness. A novel patient educational booklet, The Back Book, has been developed to provide evidence-based information and advice consistent with current clinical guidelines. METHODS: One hundred sixty-two patients were given either the experimental booklet or a traditional booklet. The main outcomes studied were fear-avoidance beliefs about physical activity, beliefs about the inevitable consequences of back trouble, the Roland Disability Questionnaire, and visual analogue pain scales. Postal follow-up response at 1 year after initial treatment was 78%. RESULTS: Patients receiving the experimental booklet showed a statistically significant greater early improvement in beliefs which was maintained at 1 year. A greater proportion of patients with an initially high fear-avoidance beliefs score who received the experimental booklet had clinically important improvement in fear-avoidance beliefs about physical activity at 2 weeks, followed by a clinically important improvement in the Roland Disability Questionnaire score at 3 months. There was no effect on pain. CONCLUSION: This trial shows that carefully selected and presented information and advice about back pain can have a positive effect on patients' beliefs and clinical outcomes, and suggests that a study of clinically important effects in individual patients may provide further insights into the management of low back pain.

Outbreak of Salmonella infantis infection in a large animal veterinary teaching hospital.

During the past 11 years, there have been numerous reports of outbreaks of salmonellosis involving horses in veterinary teaching hospitals. Some of these outbreaks have been associated with Salmonella serotypes not commonly associated with infection of horses. Salmonella infantis is among the more common Salmonella serotypes isolated from human beings, and is an important pathogen in the broiler chicken industry. However, it was not commonly isolated from horses or cattle on a national basis between 1993 and 1995. In this report, we describe an outbreak of S infantis infection among large animals, primarily horses, in a veterinary teaching hospital and the control measures that were implemented. Factors that appeared to be key in control of this outbreak in this hospital included providing biosecurity training sessions for hospital personnel, adopting a standard operating procedure manual for biosecurity procedures, installing additional handwashing sinks throughout the facility, painting the interior of the facility with a nontoxic readily cleanable paint, replacing the dirt flooring in 4 stalls with concrete flooring, and removing noncleanable surfaces such as rubber stall mats, wooden hay storage bins, and open grain bins. Our experience with this outbreak suggests that although it is virtually impossible to eliminate Salmonella organisms from the environment, minimizing contamination is possible. Prevention of nosocomial infection must be approached in a multifaceted manner and care must be taken to search out covert sources of contamination, especially if standard intervention procedures do not prevent spread of the disease.

Is ergonomic intervention alone sufficient to limit musculoskeletal problems in nurses?

This study retrospectively surveyed 1,216 nurses at hospitals in Belgium and The Netherlands. Data concerning workloads, musculoskeletal symptoms, work loss and psychosocial factors were collected by questionnaire. Lifetime prevalence rates for musculoskeletal problems and low back trouble were significantly lower in the Dutch hospitals than the Belgian hospitals, but a significantly higher proportion of Dutch nurses had 'heavy' workloads. Overall, symptoms and work loss in the previous 12 months were not related to workload, nor was the perception that work was causative; a change of duties because of symptoms was rare (< 3%). The Dutch nurses differed strikingly from Belgian nurses on the psychosocial variables; they were less depressed and significantly more positive about pain, work and activity. It is proposed that ergonomic interventions alone may be sub-optimal in controlling musculoskeletal problems among nurses. The additional provision of psychosocial information to challenge misconceptions and encourage self-management is proposed.

Occupational risk factors for the first-onset and subsequent course of low back trouble. A study of serving police officers.

STUDY DESIGN: A survey of occupational risks for low back trouble in two police forces discordant for one known physical stressor (wearing body armor weighing approximately 8.5 kg. OBJECTIVES: To determine the hazard for first-onset and subsequent course of low back trouble associated with occupational physical and psychosocial stressors. SUMMARY OF BACKGROUND DATA: Various occupational physical stressor have been associated with the prevalence of back pain, but their relationship with first-onset low back trouble is uncertain. Psychosocial factors reportedly are important determinants of chronicity. METHODS: Anamnestic data on low back trouble were collected from representative random samples of "exposed" and control forces, along with variables describing exposure to occupational physical stressors and sports results. Psychometric tests were administered. RESULTS: Occupational risk factors for first-onset low back trouble were determined from lifetables based on officers with no previous back pain history. Survival time to first onset was affected adversely by wearing body armor and, less so, by vehicular exposure and sports participation. The proportion with persistent (chronic) trouble did not depend on length of exposure since onset, but longer service was associated with recurrent episodes. Chronicity was related to distress and blaming police work. Work loss was associated with blaming work and wearing body armor. Changing to lighter duties after development of low back trouble occurred rarely. CONCLUSIONS: Exposure to occupational physical stress seems detrimental; It reduced survival time to first-onset of low back trouble. Recurrence was associated with time since onset, but persistent trouble was not. Sports participation was a risk if occupational hazards were high.

Lumbar disc degeneration and sagittal flexibility.

It is uncertain whether intervertebral disc degeneration is associated with reduced or increased flexibility, although lumbar flexibility is known to reduce with advancing age. This cross-sectional study of 214 middle-aged men attempted to determine the influence on lumbar sagittal flexibility from intervertebral disc degeneration parameters measured from magnetic resonance images (disc height, signal intensity, bulging, osteophytes). Multivariate analyses showed that a reduced extent of lumbar flexibility could be accounted for by the combined effect of decreasing disc height together with increasing age, weight, and back pain frequency. Although it remains possible that single degenerate discs will display increased mobility, the presence of discs at various stages of degeneration results in a net reduction of flexibility. The factors studied here explained only 31% of the variance in flexibility; the major determinants remain to be identified and quantified.

The natural history of low back pain in adolescents.

STUDY DESIGN: A 5-year longitudinal interview and questionnaire-based survey of back pain in adolescents. OBJECTIVES: To determine the natural history of back pain during adolescence in boys and girls and to explore the influence of sports participation and lumbar flexibility. SUMMARY OF BACKGROUND DATA: Previous data on low back pain and flexibility in adolescents have come largely from cross-sectional studies with differing definitions and age groups. A longitudinal study would offer a more detailed description of aspects of the natural history of back pain. METHODS: A cohort of 216 11-year-old children was given a structured questionnaire about back pain. Follow-up evaluation was annual for 4 more years. Lumbar sagittal mobility was measured in first and last years. Life-table analysis was the chosen statistical method. RESULTS: Annual incidence rose from 11.8% at age 12+ to 21.5% at 15+ years. Lifetime prevalence rose from 11.6% at age 11+ to 50.4% at age 15+ years. Experience of back pain was frequently forgotten. Recurrent pain was common, usually manifesting as such rather than as progression from a single episode; few children required treatment. Back pain was more common in boys than girls, especially by age 15 years. There was a positive link between sports and back pain only for boys. Severity and flexibility were not related to sex, treatment, or sport. CONCLUSIONS: Back pain in adolescents is common; it increases with age and is recurrent, but in general does not deteriorate with time. Much of the symptomatology may be considered a normal life experience, probably unrelated to adult disabling trouble.

Reproducibility of lumbar paraspinal surface electromyogram power spectra.

OBJECTIVE: To establish the reproducibility of surface recordings of electromyograms from lumbar erector spinae muscles. DESIGN: Repeated measurements in 10 male volunteers under controlled conditions. METHODS: While isometric load was held constant at (2/3) and (1/3) of maximum voluntary contraction, surface electromyograms were recorded from the 4th/5th lumbar interspace on three occasions separated by at least a day. Fresh surface electrodes were applied on each test occasion. The raw electromyographic signal was filtered and digitized and the signal processed by fast Fourier transformation to give median frequency and total amplitude spectra. Linear regression lines of median frequency and amplitude against time were calculated. The 'spectral halfwidth" was defined as the full width at half maximum of the composite amplitude spectrum. Reproducibility was assessed by calculation of the intraclass correlation coefficient. RESULTS: Reproducibility of initial median frequency and spectral halfwidth were found to be excellent at both (2/3) (ICCC 0.91 and 0.88) and (1/3) (ICCC 0.84 and 0.83) maximum voluntary contraction. Initial power and regression slopes of power and median frequency were not reproducible. CONCLUSIONS: The reproducibility of two electromyographic variables, the initial median frequency and the spectral halfwidth, were found to be satisfactory.

Do attitudes and beliefs influence work loss due to low back trouble?

Recent evidence indicates that the influence of psychosocial factors on low back disability is as great as, if not greater than, ergonomic aspects; negative attitudes and beliefs are likely to be related to absenteeism. To measure workers attitudes and beliefs about low-back trouble, pain, work and activity five questionnaires were used. Two new instruments (Back Beliefs Questionnaire and Psychosocial Aspects of Work questionnaire) were developed and tested. The attitudes and beliefs were measured among workers in a biscuit manufacturing factory, and the responses related to absenteeism. Workers who had taken in excess of one week's absence due to low-back trouble had significantly more negative attitudes and beliefs when compared with workers who had taken shorter absence (or indeed those reporting no history of back trouble). A subset of the psychosocial parameters accounted for 32% of the variance in absence. Interventions designed to reduce negative attitudes and promote positive beliefs may help to reduce detrimental, inappropriate longer-term absenteeism due to low-back trouble.

Absence resulting from low back trouble can be reduced by psychosocial intervention at the work place.

STUDY DESIGN: A 1-year prospective study in industry, assessing effects of an educational pamphlet on various psychosocial parameters and absenteeism resulting from low back trouble. OBJECTIVES: To determine the value of distributing an educational psychosocial pamphlet to reduce absenteeism resulting from back trouble. The pamphlet was designed to alter avoidance behaviors by encouraging a positive, active approach. SUMMARY OF BACKGROUND DATA: Attempts to control back-pain disability have failed. Fear of pain and activity seemingly leads to avoidance behaviors than contribute to chronicity and work loss. Avoidance behaviors are mediated by attitudes and beliefs; such attitudes and beliefs are a reasonable target for educational interventions designed to change "inappropriate" behaviors (e.g., extended absenteeism). Health education pamphlets are advocated widely but tested rarely. METHODS: Three factories participated in the study. Psychosocial data were collected by questionnaires; absence data were extracted from company records. A psychosocial pamphlet was distributed in one factory; the control subjects received either a nonspecific pamphlet or no intervention. The pamphlet emphasized a positive approach to low back trouble (reduction of negative beliefs and attitudes). RESULTS: In the company whose employees received pamphlets, a significant reduction occurred for the number of spells with extended absence and the number of days of absence (70% and 60%, respectively) compared with extrapolated values. A concomitant positive shift in beliefs concerning the locus of pain control and the inevitable consequences of low back trouble was found. CONCLUSION: A simple industrial intervention using a psychosocial pamphlet, which was designed to reduce avoidance behaviors by fostering positive beliefs and attitudes, successfully reduced extended absence resulting from low back trouble.

Psychosocial predictors of outcome in acute and subchronic low back trouble.

STUDY DESIGN: A prospective survey of patients seeking primary care for low back pain. Clinical and psychosocial data, available at presentation, were explored for predictors of outcome at 1 year. OBJECTIVES: To determine the relative value of clinical and psychosocial variables for early identification of patients with a poor prognosis. SUMMARY OF BACKGROUND DATA: Current treatment strategies for low back pain have failed to stem the rising levels of disability. Psychosocial factors have been shown to be important determinants of response to therapy in chronic patients, but the contribution from similar data in acute or subchronic patients has not been comprehensively investigated. METHODS: Two hundred fifty-two patients with low back pain, presenting to primary care, underwent a structured clinical interview and completed a battery of psychosocial instruments. Follow-up was done by mail at 1 year; outcome was measured using a back pain disability questionnaire. Predictive relationships were sought between the data at presentation and disability at follow-up. RESULTS: Most patients showed improved disability and pain scores, although more than half had persisting symptoms. Eighteen percent showed significant psychological distress at presentation. Multiple regression analysis showed the level of persisting disability to depend principally on measures in the psychosocial domain; for acute cases outcome is also dependent on the absence or presence of a previous history of low back trouble. Discriminant models successfully allocated typically 76% of cases to recovered/not-recovered groups, largely on the basis of psychosocial factors evident at presentation. CONCLUSIONS: Early identification of psychosocial problems is important in understanding, and hopefully preventing, the progression to chronicity in low back trouble.

Estimation of spinal loads in overhead work.

To explore the spinal loads occurring in overhead working postures and to assess the value of ergonomic reduction of lumbar extension, spinal strain was measured by stature change in simulated motor vehicle maintenance tasks. A field study identified the typical extent of lumbar extension incurred in this type of work. In the laboratory eight male volunteers tightened and loosened bolts both overhead and at chest-height for 30 min periods; records were made of lumbar posture, ground reaction force, and perceived exertion. Stature change was measured using a refined technique which permitted estimation of net effect of the work loads. The field study revealed that motor mechanics typically spent 8% of their time working overhead with up to 10 degrees of lumbar extension. In the laboratory study, the overhead task entailed more lumbar extension and perceived exertion than did the chest-height task; ground reaction forces did not differ substantially between tasks. Only small changes in stature were observed at the end of the work period, and there was no significant difference between the tasks (means: overhead, +0.61 mm; chest-height, -0.23 mm: p = 0.31). Stature change was significantly correlated with lordosis for overhead work such that increased lordosis (compared with chest-height work) was associated with relative stature gain. No evidence was found to indicate a need for ergonomic intervention in overhead work tasks so far as spinal loading is concerned. The lack of substantial change in stature from tasks perceived to involve moderately high levels of exertion was unexpected; it would appear that some elements of dynamic work tasks may have a relative unloading effect, and that lordotic postures reduce load on the spinal discs.

Continuous measurement of lumbar posture using flexible electrogoniometers.

Continuous measurement of changing limb segment angle is possible using a recently introduced flexible electrogoniometer but, unfortunately, the magnitude of linear displacements occurring during flexion and extension of the trunk has prevented its use as a measure of spinal mobility and posture. To overcome this limitation, a specially constructed, lightweight, aluminium carriage has been developed to allow free linear travel of the electrogoniometer, while maintaining the angle recorded between the thoracolumbar junction and the sacrum. The reliability and practicability of this new approach for recording changes in lumbar posture have been investigated. Following bench tests and operator training, measurements of maximal flexion and extension of the lumbar spine were repeated on 12 subjects. The extent of sagittal mobility was compared with measures from a fluid-filled inclinometer and a flexicurve. Analysis of the data showed that the use of the aluminium carriage did not markedly influence the accuracy of the electrogoniometer, and the technique as modified was found to be comparable with standard techniques for estimating the extent of lumbar sagittal flexibility. A field based study, involving four garage mechanics, was undertaken to examine the usability and acceptability of the electrogoniometer technique for continuous measurements. Lumbar curvature was monitored continuously for a two hour period during the course of the mechanics' working day. Dedicated software provided angle-time plots from which it was established that extreme flexed or extended postures were maintained only for relatively short periods; projection to an eight hour shift would indicate that a total of approximately 40 min is spent in extension beyond 10 degrees and flexion beyond 50 degrees. The technique has the potential to provide quantitative information on lumbar posture necessary for non-invasive, biomechanical investigations of spinal loading. It will be particularly useful for both sporting and occupational ergonomics field-studies.

Does leisure sports activity influence lumbar mobility or the risk of low back trouble?

In order to look for relationships between leisure sports activity and both low back trouble and back flexibility, 958 people, aged 10-84 years, were examined. Their history of low back trouble and leisure sports participation was recorded, together with measurements of maximal lumbar sagittal mobility. No evidence was found to suggest that the extent of sports participation either during childhood or as an adult was related to the development, frequency, or onset-age of low back trouble. Although sports participation was not associated with flexibility in schoolchildren, adults who had continued leisure sports for greater than 5 years showed relatively reduced lumbar mobility. On the basis of the results presented here, it is concluded that sporting pursuits at amateur/leisure level do not, in themselves, represent a major risk factor for low back trouble. On the contrary, it was found that adults typically continued leisure sports participation for some years after developing low back trouble. Sports participation, in general terms, is not contraindicated for those who have experienced low back trouble, but regular exercise does not apparently result in increased lumbar flexibility.

Axenic isolation of viable Giardia muris trophozoites.

Large numbers of viable Giardia muris trophozoites were isolated from the duodenum of experimentally infected mice 6 days after inoculation with 1,000 G. muris cysts. A series of shaking, incubation, and washing steps in the presence of the broad-spectrum antibiotic piperacillin readily provided 4.9 +/- 1.5 x 10(5) G. muris trophozoites per mouse, free of detectable contaminant organisms. Anaerobic and microaerophilic culturing and scanning electron microscopy demonstrated axenic status and high purity of the isolates. The viability of trophozoites was 98 +/- 2%. Application of this technique should permit novel immunological and epidemiological analyses of G. muris infection and biochemical investigations of this protozoan parasite.

Noninvasive measurement of lumbar sagittal mobility. An assessment of the flexicurve technique.

The use of flexicurves to measure lumbar sagittal mobility was subjected to a series of reliability and validation experiments. Appropriate statistical methods were described and used to quantify intraobserver and intrasubject variability and to determine limits of agreement with measurements from radiographs. It was shown that the traditional use of correlation coefficients can produce misleading or inadequate information. The flexicurve technique had an intraobserver variability of 3-4 degrees of movement, was not significantly influenced by intrasubject variability, and provided measurements typically within 6 degrees of radiographic measurements. The data suggest that the flexicurve technique is less biased than the inclinometric method. These results demonstrate the use of suitable statistical methods to assess the clinical usefulness, or level of interchangeability, of spinal measurement instruments.

Prediction of the clinical course of low-back trouble using multivariable models.

The inability to predict outcome in patients with low-back pain seriously impedes clinical trials and leads to inappropriate or unnecessary treatment. This prospective study investigated the value of multivariable mathematical models to predict the 1-year clinical course of 109 patients with low-back trouble (LBT). Discriminant analysis was used to determine predictive models for outcome groups at 1 month, 3 months and 1 year. The variables selected in the analyses were subsets of 29 items from a clinical interview at presentation. These included anamnestic features of the first episode as well as symptomatic details and results from clinical tests for the current spell. The derived models successfully discriminated outcome groups with estimates of sensitivity and specificity ranging from 63 to 99%. When models from one set of patients were tested for predictive accuracy by the application of them to a different set, nonrecovery and satisfactory improvement were predicted with a 76-100% success rate. The results affirmed the importance of considering combinations of interrelated variables for prediction and discrimination in LBT. This work has demonstrated that outcome can be predicted successfully by the use of mathematic models based just on presentation data. The ability to determine homogenous groups in respect to outcome is seen as an important aid to therapeutic research; further work will enable refinement of these models for general clinical use and for incorporation into computer-based interview systems.