Assessing a GPS-Based 6-Minute Walk Test for People With Persistent Pain: Validation Study

BACKGROUND

The 6-minute walk test (6MWT) is a commonly used method to assess the exercise capacity of people with many health conditions, including persistent pain. However, it is conventionally performed with in-person supervision in a hospital or clinic, therefore requiring staff resources. It may also be difficult when in-person supervision is unavailable, such as during the COVID-19 pandemic, or when the person is geographically remote. A potential solution to these issues could be to use GPS to measure walking distance.

OBJECTIVE

The primary aim of this study was to assess the validity of a GPS-based smartphone app to measure walking distance as an alternative to the conventional 6MWT in a population with persistent pain. The secondary aim of this study was to estimate the difference between the pain evoked by the 2 test methods.

METHODS

People with persistent pain (N=36) were recruited to complete a conventional 6MWT on a 30-m shuttle track and a 6MWT assessed by a smartphone app using GPS, performed on outdoor walking circuits. Tests were performed in random order, separated by a 15-minute rest. The 95% limits of agreement were calculated using the Bland-Altman method, with a specified maximum allowable difference of 100 m. Pain was assessed using an 11-point numerical rating scale before and after each walk test.

RESULTS

The mean 6-minute walk distance measured by the GPS-based smartphone app was 13.2 (SD 46; 95% CI -2.7 to 29.1) m higher than that assessed in the conventional manner. The 95% limits of agreement were 103.9 (95% CI 87.4-134.1) m and -77.6 (95% CI -107.7 to -61) m, which exceeded the maximum allowable difference. Pain increased in the conventional walk test by 1.1 (SD 1.0) points, whereas pain increased in the app test by 0.8 (SD 1.4) points.

CONCLUSIONS

In individuals with persistent pain, the 2 methods of assessing the 6MWT may not be interchangeable due to limited validity. Potential reasons for the differences between the 2 methods might be attributed to the variation in track layout (shuttle track vs continuous circuit); poor GPS accuracy; deviations from the 30-m shuttle track; human variability in walking speed; and the potential impact of a first test on the second test due to fatigue, pain provocation, or a learning effect. Future research is needed to improve the accuracy of the GPS-based approach. Despite its limitations, the GPS-based 6MWT may still have value as a tool for remote monitoring that could allow individuals with persistent pain to self-administer frequent assessments of their functional capacity in their home environment.

Comparison of physiological and behavioral nutrition-related factors in people with and without adolescent idiopathic scoliosis, from cohort data at 8 to 20 years

Nutrition-related variables including lower body mass index (BMI), lower bone mineral density (BMD), altered body composition and hormone levels have been reported in adolescent idiopathic scoliosis (AIS). The aims of this study were to determine if physiological and behavioral nutrition-related factors differ between people with and without AIS, and to quantify their relationship with AIS, in unbiased cohort sample. BMI, presence of an eating disorder, leptin, adiponectin, BMD, vitamin D, lean mass, and fat mass were compared between those with and without AIS at ages 8, 10, 14, 17, and 20 years, and multiple logistic regression was performed between these variables and AIS. Lower total body BMD (median, 1.0 g/cm2 vs 1.1 g/cm2; p = .03) and lean mass (median, 38.8 kg vs 46.0 kg; p = .04) at age 20 years were observed in those with AIS compared to those without scoliosis. At age 20, the odds of AIS were 3.23 times higher for adolescents with an eating disorder compared to those with no eating disorder (95% CI, 1.02-8.63) when adjusted for BMI. Every 1 kg/m2 increase in BMI decreased the odds of AIS by 0.88 times (95% CI, 0.76-0.98), after adjusting for eating disorder diagnosis. In conclusion, lower BMI in mid-adolescence and presence of eating disorder outcomes, lower BMD, and lower lean mass in late adolescence were associated with the presence of AIS. Current data do not explain the mechanisms for these associations but suggest that serum leptin, adiponectin, and vitamin D are unlikely to be contributing factors. Conclusive determination of the prevalence of eating disorders in AIS will require further studies with larger sample sizes.

Quantifying Muscle Size Asymmetry in Adolescent Idiopathic Scoliosis Using Three-dimensional Magnetic Resonance Imaging

STUDY DESIGN

This is a case-control study of prospectively collected data.

OBJECTIVE

To quantify paraspinal muscle size asymmetry in adolescent idiopathic scoliosis (AIS) and determine if this asymmetry is (i) greater than observed in adolescent controls with symmetrical spines; and (ii) positively associated with skeletal maturity using Risser grade, scoliosis severity using the Cobb angle, and chronological age in years.

SUMMARY OF BACKGROUND DATA

AIS is a three-dimensional deformity of the spine which occurs in 2.5% to 3.7% of the Australian population. There is some evidence of asymmetry in paraspinal muscle activation and morphology in AIS. Asymmetric paraspinal muscle forces may facilitate asymmetric vertebral growth during adolescence.

METHODS

An asymmetry index [Ln(concave/convex volume)] of deep and superficial paraspinal muscle volumes, at the level of the major curve apex (Thoracic 8-9 th vertebral level) and lower-end vertebrae ( LEV , Thoracic 10-12 th vertebral level), was determined from three-dimensional Magnetic Resonance Imaging of 25 adolescents with AIS (all right thoracic curves), and 22 healthy controls (convex=left); all female, 10 to 16 years.

RESULTS

Asymmetry index of deep paraspinal muscle volumes was greater in AIS (0.16±0.20) than healthy spine controls (-0.06±0.13) at the level of the apex ( P <0.01, linear mixed-effects analysis) but not LEV ( P >0.05). Asymmetry index was positively correlated with Risser grade ( r =0.50, P <0.05) and scoliosis Cobb angle ( r =0.45, P <0.05), but not age ( r =0.34, P >0.05). There was no difference in the asymmetry index of superficial paraspinal muscle volumes between AIS and controls ( P >0.05).

CONCLUSIONS

The asymmetry of deep apical paraspinal muscle volume in AIS at the scoliosis apex is greater than that observed at equivalent vertebral levels in controls and may play a role in the pathogenesis of AIS.

Acceptability of a Pain History Assessment and Education Chatbot (Dolores) Across Age Groups in Populations With Chronic Pain: Development and Pilot Testing

BACKGROUND

The delivery of education on pain neuroscience and the evidence for different treatment approaches has become a key component of contemporary persistent pain management. Chatbots, or more formally conversation agents, are increasingly being used in health care settings due to their versatility in providing interactive and individualized approaches to both capture and deliver information. Research focused on the acceptability of diverse chatbot formats can assist in developing a better understanding of the educational needs of target populations.

OBJECTIVE

This study aims to detail the development and initial pilot testing of a multimodality pain education chatbot (Dolores) that can be used across different age groups and investigate whether acceptability and feedback were comparable across age groups following pilot testing.

METHODS

Following an initial design phase involving software engineers (n=2) and expert clinicians (n=6), a total of 60 individuals with chronic pain who attended an outpatient clinic at 1 of 2 pain centers in Australia were recruited for pilot testing. The 60 individuals consisted of 20 (33%) adolescents (aged 10-18 years), 20 (33%) young adults (aged 19-35 years), and 20 (33%) adults (aged >35 years) with persistent pain. Participants spent 20 to 30 minutes completing interactive chatbot activities that enabled the Dolores app to gather a pain history and provide education about pain and pain treatments. After the chatbot activities, participants completed a custom-made feedback questionnaire measuring the acceptability constructs pertaining to health education chatbots. To determine the effect of age group on the acceptability ratings and feedback provided, a series of binomial logistic regression models and cumulative odds ordinal logistic regression models with proportional odds were generated.

RESULTS

Overall, acceptability was high for the following constructs: engagement, perceived value, usability, accuracy, responsiveness, adoption intention, esthetics, and overall quality. The effect of age group on all acceptability ratings was small and not statistically significant. An analysis of open-ended question responses revealed that major frustrations with the app were related to Dolores' speech, which was explored further through a comparative analysis. With respect to providing negative feedback about Dolores' speech, a logistic regression model showed that the effect of age group was statistically significant (χ22=11.7; P=.003) and explained 27.1% of the variance (Nagelkerke R2). Adults and young adults were less likely to comment on Dolores' speech compared with adolescent participants (odds ratio 0.20, 95% CI 0.05-0.84 and odds ratio 0.05, 95% CI 0.01-0.43, respectively). Comments were related to both speech rate (too slow) and quality (unpleasant and robotic).

CONCLUSIONS

This study provides support for the acceptability of pain history and education chatbots across different age groups. Chatbot acceptability for adolescent cohorts may be improved by enabling the self-selection of speech characteristics such as rate and personable tone.

Yarning about pain: Evaluating communication training for health professionals at persistent pain services in Queensland, Australia

Background

Providing cultural education to health professionals is essential in improving the quality of care and outcomes for Aboriginal and Torres Strait Islander patients. This study reports the evaluation of a novel training workshop used as an intervention to improve communication with Aboriginal and Torres Strait Islander patients of persistent pain services.

Methods

In this single-arm intervention study, health professionals undertook a one-day workshop, which included cultural capability and communication skills training based on a clinical yarning framework. The workshop was delivered across three adult persistent pain clinics in Queensland. At the end of the training, participants completed a retrospective pre/post evaluation questionnaire (5 points Likert scale, 1 = very low to 5 = very high), to rate their perceived importance of communication training, their knowledge, ability and confidence to communicate effectively. Participants also rated their satisfaction with the training and suggested improvements for future trainings.

Results

Fifty-seven health professionals were trained (N = 57/111; 51% participation rate), 51 completed an evaluation questionnaire (n = 51/57; 90% response rate). Significant improvements in the perceived importance of communication training, knowledge, ability and confidence to effectively communicate with Aboriginal and Torres Strait Islander patients were identified (p < 0.001). The greatest increase was in the perceived confidence pre-training mean of 2.96 (SE = 0.11) to the post-training mean of 4.02 (SE = 0.09).

Conclusion

This patient-centred communication training, delivered through a novel model that combines cultural capability and the clinical yarning framework applied to the pain management setting, was highly acceptable and significantly improved participants' perceived competence. This method is transferrable to other health system sectors seeking to train their clinical workforce with culturally sensitive communication skills.

Advancing Use of DEXA Scans to Quantitatively and Qualitatively Evaluate Lateral Spinal Curves, for Preliminary Identification of Adolescent Idiopathic Scoliosis

Dual-energy X-ray absorptiometry (DEXA) scan is an emerging screening method for identifying likely adolescent idiopathic scoliosis (AIS). Using DEXA in an unbiased population sample (the Raine Study), we aimed to report the inter-rater reliability and minimal detectable change (MDC₉₅) for scoliosis curve angle measurement, identify likely AIS prevalence, and the concordance between reported AIS diagnosis and DEXA-identified likely AIS. Scoliosis curve angles were measured using the modified Ferguson method on DEXA scans (n = 1238) at age 20 years. For curve angle inter-rater reliability, two examiners measured angles (6-40°) on 41 scans. Likely, AIS was determined with quantitative and qualitative criteria (modified Ferguson angles ≥ 10° and expert review of spinal curves).The inter-rater reliability for scoliosis curve angle measurement was good-excellent (ICC: 0.82; 95% CI: 0.71-0.89; p < 0.001), and MDC₉₅ was 6.2°. The prevalence of likely AIS was 2.1% (26/1238). Diagnosis of AIS was reported despite little or no scoliosis curve (< 3.8°) for 20 participants (1.6%), and diagnosis of AIS was not reported despite scoliosis curve ≥ 10° for 11 participants (0.9%). Results support the use of modified Ferguson method to measure scoliosis curve angles on DEXA. There is potential utility for using a combination of quantitative measurement and qualitative criteria to evaluate DEXA images, to identify likely AIS for reporting prevalence. Without formal school screening, the analysis of DEXA in this population sample suggested that relying on current health professional diagnosis alone could result in 2.5% of this cohort being at risk of false positive diagnosis or delay in necessary management due to non-diagnosis of AIS.

People at a persistent pain service can walk it, but some struggle to talk about it: Reliability, detectable difference and clinically important difference of the six-minute walk test

OBJECTIVES

The six-minute walk test (6MWT) is a commonly used measure of functional capacity. This study is the first to investigate the test-retest reliability, minimal detectable difference (MDD) and the minimal clinically important difference (MCID) for people attending a persistent pain service. Relationships between change in 6MWT performance and change in self-reported physical, functional and psychological outcome measures were also explored.

METHODS

A cross-sectional repeated measures design was used with people having >9 months of pain attending an 8-week outpatient persistent pain programme. For reliability and MDD, 27 people were recruited, for MCID calculations, 32 people were recruited. The MCID was examined by dichotomising people into "improvers", or "non-improvers" based upon the Global Rating of Change (GRC) in physical abilities score.

RESULTS

The mean (SD) 6MWT distance was 389.4 (93.6) m at programme start, and 427.8 (83.0) m at week eight completion. The test-retest reliability was good (intraclass correlation coefficient = 0.89) and the MDD = 86.1 m. As there was no relationship between change in 6MWT distance and GRC physical abilities at week eight (r = 0.132, p = 0.472) the MCID could not be calculated. Furthermore, no relationships were found between change in 6MWT distance and other self-reported measures. Changes in GRC physical abilities and 6MWT were frequently discordant, with increased 6MWT for 7/11 "GRC non-improvers" and decreased 6MWT for 7/21 "GRC improvers".

CONCLUSIONS

Amongst this cohort, change in physical ability may or may not be reflected by self-reported change. Objective tests of physical ability are recommended for people attending pain services, and validated tests should align with intervention aims.

Communication and access to healthcare: Experiences of Aboriginal and Torres Strait Islander people managing pain in Queensland, Australia

Background

Pain management requires a multidisciplinary approach and a collaborative relationship between patient-provider in which communication is crucial. This study examines the communication experiences of Aboriginal and Torres Strait Islander patients and Aboriginal and Torres Strait Islander Hospital Liaison Officers (ATSIHLOs), to improve understanding of how pain is managed in and through patient-health professional communication.

Methods

This qualitative study involved a purposive sample of patients attending three persistent pain clinics and ATSIHLOs working in two hospitals in Queensland, Australia. Focus groups and in-depth interviews explored the communication experiences of patients managing pain and ATSIHLOs supporting patients with pain. This study adopted a descriptive phenomenological methodology, as described by Colaizzi (1978). Relevant statements (patient and ATSIHLOs quotes) about the phenomenon were extracted from the transcripts to formulate meanings. The formulated meanings were subsequently sorted into thematic clusters and then integrated into themes. The themes were then incorporated into a concise description of the phenomenon of communication within pain management. Findings were validated by participants.

Results

A total of 21 Aboriginal and Torres Strait Islander participants were involved in this study. Exploration of the communication experiences of patients and ATSIHLOs revealed overlapping themes of important barriers to and enablers of communication that affected access to care while managing pain. Acknowledging historical and cultural factors were particularly important to build trust between patients and health professionals. Some patients reported feeling stigmatized for identifying as Aboriginal and Torres Strait Islander, while others were reluctant to disclose their background for fear of not having the same opportunity for treatment. Differences in the expression of pain and the difficulty to use standard pain measurement scales were identified. Communication was described as more than the content delivered, it is visual and emotional expressed through body language, voice intonation, language and the speed of the conversation.

Conclusion

Communication can significantly affect access to pain management services. Aboriginal and Torres Strait Islander patients highlighted the burden of emotional pain caused by historical factors, negative stereotypes and the fear of discrimination. Pain management services and their health professionals need to acknowledge how these factors impact patients trust and care.

Study protocol: Clinical yarning, a communication training program for clinicians supporting aboriginal and Torres Strait Islander patients with persistent pain: A multicentre intervention feasibility study using mixed methods

Objectives

Ineffective communication between healthcare clinicians and Aboriginal and Torres Strait Islander patients with persistent pain is a significant barrier to optimal pain management. This manuscript is a study protocol and describes the development and evaluation methods of a tailored, culturally-informed training program, to improve clinicians’ communication with patients.

Study design

This is a single-arm, multicentre (2 metropolitan and 1 regional persistent pain service) intervention feasibility study that will be evaluated using mixed methods.

Methods

A communication training program will be developed informed by qualitative interviews with key stakeholders, and adapt the patient-centred ‘clinical yarning’ framework for the Queensland context. Evaluation of the effectiveness of the training will involve the analysis of quantitative data collected at three study sites over a 12-month period. At the patient level, communication experience will be rated at differing times of the training rollout to reflect participants' experience of communication either prior to or following the treating clinician attending the communication training. At the clinician level, evaluation of the training program will be based on changes of ratings in the importance of training, knowledge, ability and confidence to communicate with Aboriginal and Torres Strait Islander patients; satisfaction, acceptance and relevance to their clinical practice. This study will be grounded in the needs and preferences of communication of Aboriginal and Torres Strait Islander people living with pain.

Conclusion

It is hypothesized that the patient-centred intervention will have immediate benefits for patients, improving patient experience of care. This research will focus on an area of unmet need in addressing persistent pain.

Does foot mobility affect the outcome in the management of patellofemoral pain with foot orthoses versus hip exercises? A randomised clinical trial

Objectives

To test (i) if greater foot pronation (measured as midfoot width mobility) is associated with better outcomes with foot orthoses treatment, compared with hip exercises and (ii) if hip exercises are superior to foot orthoses, irrespective of midfoot width mobility.

Methods

A two-arm parallel, randomised superiority clinical trial was conducted in Australia and Denmark. Participants (18–40 years) were included who reported an insidious onset of knee pain (≥6 weeks duration); ≥3/10 numerical pain rating, that was aggravated by activities (eg, stairs, squatting, running). Participants were stratified by midfoot width mobility (high ≥11 mm change in midfoot width) and site, randomised to foot orthoses or hip exercises and blinded to objectives and stratification. Success was defined a priori as much better or better on a patient-perceived 7-point scale at 12 weeks.

Results

Of 218 stratified and randomised participants, 192 completed 12-week follow-up. This study found no difference in success rates between foot orthoses versus hip exercises in those with high (6/21 vs 9/20; 29% vs 45%, respectively) or low (42/79 vs 37/72; 53% vs 51%) midfoot width mobility. There was no association between midfoot width mobility and treatment outcome (Interaction effect p=0.19). This study found no difference in success rate between foot orthoses versus hip exercises (48/100 vs 46/92; 48% vs 50%).

Conclusion

Midfoot width mobility should not be used to help clinicians decide which patient with patellofemoral pain might benefit most from foot orthoses. Clinicians and patients may consider either foot orthoses or hip exercises in managing patellofemoral pain.

Trial registration number

ACTRN12614000260628.

The Foot Orthoses versus Hip eXercises (FOHX) trial for patellofemoral pain: a protocol for a randomized clinical trial to determine if foot mobility is associated with better outcomes from foot orthoses

BACKGROUND

Patellofemoral pain (PFP) is a prevalent, often recalcitrant and multifactorial knee pain condition. One method to optimize treatment outcome is to tailor treatments to the patient's presenting characteristics. Foot orthoses and hip exercises are two such treatments for PFP with proven efficacy yet target different ends of the lower limb with different proposed mechanisms of effect. These treatments have not been compared head-to-head, so there is a dearth of evidence for which to use clinically. Only foot orthoses have been explored for identifying patient characteristics that might predict a beneficial effect with either of these two treatments. Preliminary evidence suggests patients will do well with foot orthoses if they have a midfoot width in weight bearing that is ≥ 11 mm more than in non-weight bearing, but this has yet to be verified in a study that includes a comparator treatment and an adequate sample size. This trial will determine if: (i) hip exercises are more efficacious than foot orthoses, and (ii) greater midfoot width mobility will be associated with success with foot orthoses, when compared to hip exercises.

METHODS

Two hundred and twenty participants, aged 18-40 years, with a clinical diagnosis of PFP will be randomly allocated with a 1:1 ratio to receive foot orthoses or progressive resisted hip exercises, and stratified into two subgroups based on their presenting midfoot width mobility (high mobility defined as ≥11 mm). The primary outcome will be a 7-point Likert scale for global rating of change. All analyses will be conducted on an intention-to-treat basis using regression models.

DISCUSSION

This trial is designed to compare the efficacy of foot orthoses versus hip exercise, as well as to determine if high midfoot width mobility is associated with better outcomes with foot orthoses when compared to hip exercises. Results of this trial will assist clinicians in optimising the management of those with PFP by testing whether a simple measure of midfoot width mobility can help to determine which patients are most likely to benefit from foot orthoses.

TRIAL REGISTRATION

This trial is registered on the Australian New Zealand Clinical Trials Register (ACTRN12614000260628).

Can we predict the outcome for people with patellofemoral pain? A systematic review on prognostic factors and treatment effect modifiers

BACKGROUND

Patellofemoral pain (PFP) is a multifactorial and often persistent knee condition. One strategy to enhance patient outcomes is using clinically assessable patient characteristics to predict the outcome and match a specific treatment to an individual.

AIM

A systematic review was conducted to determine which baseline patient characteristics were (1) associated with patient outcome (prognosis); or (2) modified patient outcome from a specific treatment (treatment effect modifiers).

METHODS

6 electronic databases were searched (July 2016) for studies evaluating the association between those with PFP, their characteristics and outcome. All studies were appraised using the Epidemiological Appraisal Instrument. Studies that aimed to identify treatment effect modifiers underwent a checklist for methodological quality.

RESULTS

The 24 included studies evaluated 180 participant characteristics. 12 studies investigated prognosis, and 12 studies investigated potential treatment effect modifiers. Important methodological limitations were identified. Some prognostic studies used a retrospective design. Studies aiming to identify treatment effect modifiers often analysed too many variables for the limiting sample size and typically failed to use a control or comparator treatment group. 16 factors were reported to be associated with a poor outcome, with longer duration of symptoms the most reported (>4 months). Preliminary evidence suggests increased midfoot mobility may predict those who have a successful outcome to foot orthoses.

CONCLUSIONS

Current evidence can identify those with increased risk of a poor outcome, but methodological limitations make it difficult to predict the outcome after one specific treatment compared with another. Adequately designed randomised trials are needed to identify treatment effect modifiers.

Tau protein level in cerebrospinal fluid is increased in patients with early multiple sclerosis

Axonal damage has been proposed as the major substrate of permanent clinical disability in multiple sclerosis. Tau protein, a microtubule-associated protein localised in neuronal axons, may serve as a biochemical surrogate marker to evaluate axonal damage in vivo.We intended to determine the extent of axonal damage in different stages and clinical subtypes of MS by investigating cerebrospinal fluid tau concentrations. Tau was measured using an immunoassay in 35 patients with relapsing—remitting MS, eight patients with secondary progressive MS, nine patients with primary progressive MS, 50 patients with clinically isolated syndrome suggestive of early MS and 46 normal controls. Cerebrospinal fluid tau was significantly elevated in MS compared with normal controls (median 206.0 pg/mL versus152.0 pg/mL;P=0.002). No significant difference among different subtypes of MS could be detected, although highest levels were found in very early disease stages. There was a significant elevation of CSF tau among patients with gadolinium-enhancing brain lesions in magnetic resonance imaging (P=0.02) and a tendency towards higher CSF tau levels in patients with pronounced intrathecal IgG synthesis, supporting the notion that axonal damage is influenced by inflammatory activity.

Manual handling: differences in perceived effort, success rate and kinematics between three different pushing techniques

This study examined the perceived effort, success rates and kinematics for three push strategies in a simulated lateral patient transfer (horizontal slide). Thirteen healthy subjects (four males) completed three repetition pushing loads of 6, 10 and 14 kg in random order; with a spontaneous push strategy, then with a straight-back bent-knees (squat) strategy and the preparatory pelvic movement ('rockback') strategy in random order. Perceived effort and kinematic parameters measured at the onset of movement and at maximum push excursion were compared between strategies and between loads with repeated measures ANOVA. The spontaneous and 'rockback' strategies achieved the pushing task with less perceived effort across all loads than the squat push (P < 0.001). Only 3/13 participants were successful on all attempts at pushing the 14 kg load using a squat strategy, which contrasted with 12/13 participants when the spontaneous strategy or the 'rockback' strategy was used. Forward movement of the pelvis and forward trunk inclination may be positively associated with lower perceived effort in the push task. Practitioner Summary: In a manual-handling task that simulated a lateral patient transfer (horizontal slide), perceived effort and success rates of three push strategies were compared. A straight-back bent-knees push (squat) strategy demonstrated greater perceived effort and lower success rates than a spontaneous push strategy, or a push strategy with preparatory 'rockback' pelvic movement.

Leptospirosis in dogs: a review with emphasis on clinical aspects

Leptospirosis is a bacterial disease affecting several mammalian species, including human beings. In dogs, it is spread mainly by rodents that act as a maintenance host for several Leptospira serovars. Until recently, the most common signs observed in affected dogs consisted of icterus and haemorrhagic diathesis, but today the most prevalent clinical signs are attributed to acute renal failure. The current literature gives a good review of leptospirosis in dogs in the USA and Canada, but less information is available about its occurrence in Europe. This review considers the clinical signs, diagnosis, treatment and prevention of this emerging zoonotic disease.

Sitting versus standing: Does the intradiscal pressure cause disc degeneration or low back pain?

Studies of lumbar intradiscal pressure (IDP) in standing and upright sitting have mostly reported higher pressures in sitting. It was assumed clinically that flexion of the lumbar spine in sitting relative to standing, caused higher IDP, disc degeneration or rupture, and low back pain. IDP indicates axial compressive load upon a non-degenerate disc, but provides little or no indication of shear, axial rotation or bending. This review is presented in two main parts. First, in vivo IDP data in standing and upright sitting for non-degenerate discs are comprehensively reviewed. As methodology, results and interpretations varied between IDP studies, in vivo studies measuring spinal shrinkage and spinal internal-fixator loads to infer axial compressive load to the discs are also reviewed. When data are considered together, it is clear that IDP is often similar in standing and sitting. Secondly, clinical assumptions related to IDP in sitting are considered in light of basic and epidemiologic studies. Current studies indicate that IDP in sitting is unlikely to pose a threat to non-degenerate discs, and sitting is no worse than standing for disc degeneration or low back pain incidence. If sitting is a greater threat for development of low back pain than standing, the mechanism is unlikely to be raised IDP.

["Ligament balancing" and varus deformity in total knee arthroplasty]

Coordinated bone resection and ligament balancing techniques represent prerequisites for long-term success in bicondylar total knee arthroplasty to correct mechanical leg axis and create a stable and balanced prosthesis over the entire range of motion. This review summarizes current ligament balancing techniques in knee arthroplasty to correct varus deformities. As ligament balancing techniques can only be discussed in the context of the principal surgical implantation technique and preoperative deformity, this review article defines evidence-based goals of correct implantation in knee arthroplasty, followed by a description of preoperative deformities and functional deficits of varus knees and their implications for soft tissue management. Then, principal implantation techniques in knee arthroplasty are illustrated and surgical techniques for successful ligament balancing are explained. Finally, evidence of current ligament balancing techniques is critically discussed.

Identifizierung von Risikofaktoren postoperativer Komplikationen in der primären Knieendoprothetik

AIM

Postoperative complications following primary total knee replacement performed between 2000 and 2002 were assessed to determine perioperative patient- and procedure-related risks associated with the procedure.

METHODS

For this analysis, the data collected during postoperative hospitalization for 17,644 total knee arthroplasties were assessed. The analysis included two steps. First, using logistic regression, we identified and quantified significant risk factors for the occurrence of general postoperative complications. Second, univariate analysis was utilized to qualitatively and quantitatively analyze the influence of these significant risk factors on the occurrence of major complications (hematoma, cardiovascular complication, deep venous thrombosis, pulmonary embolism, joint infection, and pneumonia).

RESULTS

General postoperative complications were reported in 11.3%. Major postoperative complications occurred in 7.2% with hematoma in 2.9%, cardiovascular complications in 1.8%, deep venous thrombosis in 1.2%, pulmonary embolism in 0.2%, joint infection in 0.8%, and pneumonia in 0.3%. Patient-related risk factors such as age, surgery time, gender, high ASA classification as well as procedure-related risk factors such as allogeneic blood transfusions and lateral release significantly increased the rate of postoperative complications. Males were more prone to hematoma, joint infection, and pneumonia in the immediate postoperative course than females, who were more in danger of developing deep venous thrombosis. Allogeneic blood transfusions increased the risk for postoperative hematoma, infection, and cardiovascular complication. Regional anesthesia was shown to decrease the risk for the occurrence of postoperative deep venous thrombosis and pulmonary embolism.

CONCLUSIONS

Postoperative complications in total knee replacement are increased in males and elder patients. Increased time of surgery and allogeneic blood transfusions also represent important risk factors for postoperative complications following primary total knee replacement.

Reversible impaired memory induced by pulsed methylprednisolone in patients with MS

Thirty patients with multiple sclerosis were randomized to 500 or 2,000 mg of methylprednisolone (MP) over 5 days. They were prospectively studied neuropsychologically before and at days 6 and 60 after onset of the therapy, using a double-blind study design. Patients showed selective deterioration of declarative memory retrieval at day 6, which was fully reversible at day 60. Although the sample size was small, these effects were independent of the administered MP dose.

Effect of stand age on fine-root biomass and biomass distribution in three European forest chronosequences

Fine-root (<2 mm) biomass and biomass distribution were determined in different age-classes of three European forest chronosequences dominated by Fagus sylvatica L., Picea abies (L.) Karst., and Quercus cerris L., respectively. Root samples were taken with the auger method. There was a clear effect of stand age on standing fine-root biomass, with the highest fine-root biomass in adult but not mature stands. The vertical fine-root biomass distribution showed, at all sites, high densities of roots in the top soil layers and with depth a gradual decrease of fine-root biomass density. The difference in total fine-root biomass between the different age-classes appeared to be due to differences in the top soil layers. Fine-root biomass in the lower soil layers was less variable along the life cycle of the forests. Only in very young stands, specific root length of fine roots was higher than in the other age-classes. The present data together with other published values suggest that fine-root biomass in tree stands develops in three phases: rapid increase after a clear-cut harvest up to a maximum of fine-root biomass; a decrease during maturation of the stand; and a steady-state in mature stands.

Isolated blood–cerebrospinal fluid barrier dysfunction: prevalence and associated diseases

OBJECTIVE

An isolated dysfunction of the blood-CSF barrier is characterised by an abnormal elevation of the albumin CSF/serum concentration ratio (Q(alb)) without any other pathological CSF findings. Although common in routine CSF analysis, the clinical significance of an isolated barrier dysfunction frequently remains unclear. We examined neurological disorders associated with an isolated elevation of Q(alb) to identify possible determinants of blood-CSF barrier dysfunction.

METHODS

367 patients (124 women, 243 men, median age 60. 0 years) out of 3,873 patients receiving diagnostic lumbar puncture at the University Hospital of Ulm (Germany) showed an isolated dysfunction of the blood-CSF barrier. Clinical data as well as MRI findings of these patients were analysed.

RESULTS

Isolated barrier dysfunction occurred most frequently (> 30%) in Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), normal pressure hydrocephalus (NPH), lumbar spinal stenosis, and polyneuropathy (PNP). In patients who showed no other evidence of neurological disease, isolated barrier dysfunction was found in 14. 9% of cases. The extent of barrier dysfunction was most prominent in brain tumours, GBS, and CIDP. There was a significant correlation of Q(alb) with both weight and body mass index (BMI).

CONCLUSIONS

Although isolated barrier dysfunction may be found in a variety of neurological diseases, it is especially frequent in GBS, CIDP, NPH, spinal canal stenosis, and PNP. In these patients, disease-related mechanisms contributing to barrier dysfunction are likely. Moreover, barrier function seems to be influenced by disease-independent determinants like weight and BMI.

The relationship between lysis and loosening in failed anatomic medullary locking components

Lysis does not cause loosening of extensively porous-coated, apparently well-fixed femoral components. We attribute this in large part to the fact that the area of strongest bone ingrowth is in the femoral diaphysis remote from the joint space. In contrast, for the acetabular component, osteolysis can be the sole or a contributing factor to loosening. We attribute this difference to the fact that the bone-implant interface of the acetabular component is much closer to the joint space and more readily accessible to osteolytic damage. In the future, with improved bearing surfaces, lysis may occur less frequently. Whether lysis is diminished as a result of these new designs, the authors contend that without adequate initial fixation, loosening will still occur. Because of our observations concerning osteolysis and loosening, we are more cautious in revising patients for osteolyis and do not revise when osteolysis first becomes apparent. Rather, we closely monitor osteolysis in these patients. For us, the question of when to operate for osteolysis remains unanswered.

Recessively inherited amyotrophic lateral sclerosis: a Germany family with the D90A CuZn-SOD mutation

Mutations of the SOD1 gene encoding the free radical scavenging enzyme copper-zinc superoxide dismutase (CuZn-SOD) occur in patients with familial amyotrophic lateral sclerosis (ALS). Recent reports have shown homozygosity for a CuZn-SOD mutation in exon 4, the D90A (Asp90A1a) mutation. Other mutations described to date show an autosomal dominant pattern of inheritance. This is the first description of autosomal recessively inherited ALS in an out-bred population in central Europe. This study confirms the earlier described characteristic phenotype reported in D90A homozygous ALS patients in Scandinavia and supports the theory of the existence of a strong modifying factor in some cases of ALS associated with mutations in the CuZn-SOD gene.

[Molecular biology findings in amyotrophic lateral sclerosis]

At presently, the etiology and pathogenesis of amyotrophic lateral sclerosis (ALS) are unknown. In recent years, the genetic background of hereditary motor neuron diseases has been partly defined. In particular, these advances represent an opportunity to improve our understanding of the pathogenesis of the familial and sporadic forms of ALS and thus provide a basis for rational therapeutic approaches. In this article, recent findings on the pathogenesis of the familial form of ALS and their implications for the sporadic form are discussed.

Cu,Zn SOD in German families with ALS

We studied the gene for Cu,Zn SOD in 15 German patients with familial ALS and did not find any mutation. Activity of the enzyme and its expression at the protein level was also normal in each patient and in 18 patients suffering from the sporadic form of ALS.

Ventricular enlargement, clinical correlates and treatment outcome in chronic schizophrenic inpatients

The ventricle-brain ratio (VBR) of 42 chronic schizophrenic patients was compared with that of 42 age-matched medical controls. For the schizophrenics, the relationship of various clinical parameters to the VBR was assessed, and the outcome of 12 weeks of double-blind treatment with either risperidone or haloperidol. The results confirm that schizophrenic patients have slightly enlarged lateral ventricles compared with medical controls. Only for schizophrenics, an effect of age, but not of duration of illness, was noticed. This study does not support the validity of a clinical subdivision of chronic schizophrenic patients on the basis of the VBR. Neither negative, positive nor general psychopathological symptoms, as measured by the Positive and Negative Syndrome Scale for Schizophrenia (PANSS), were related to the VBR, nor were abnormal involuntary movements or extrapyramidal symptoms. No association between season of birth or a family history of major mental disorder and VBR could be demonstrated. Treatment response was predicted by the total PANSS score and the PANSS general psychopathology subscale score at baseline. There was a trend for patients with higher VBR to have a more or haloperidol). or haloperidol).

Risperidone versus haloperidol in the treatment of chronic schizophrenic inpatients: a multicentre double-blind comparative study

Forty-four chronic schizophrenic inpatients participated in this multicentre 12-week parallel-group double-blind trial. After a run-in period of 2 weeks and a single-blind placebo wash-out of 1 week, they were randomly assigned to treatment with either the serotonin2 and dopamine-D2 antagonist risperidone or haloperidol. Two patients were excluded from the efficacy analysis. Five patients dropped out in the haloperidol group and 1 in the risperidone group. At the end of the trial, the mean daily dose was 12 mg for risperidone and 10 mg for haloperidol. The risperidone group showed greater improvement on the Positive and Negative Syndrome Scale for Schizophrenia, the Schedule for Affective Disorders and Schizophrenia-change version, and the Nurses' Observation Scale for Inpatient Evaluation. The improvement of negative symptoms was more pronounced in the risperidone group until week 8 of double-blind treatment. The consumption of antiparkinsonian medication was 10 times lower with risperidone. Both drugs were well tolerated and the laboratory, endocrinological and cardiovascular safety parameters were comparable. This study suggests that risperidone is comparable to haloperidol as an antipsychotic, but that it has a safer EPS profile.

Photoperiodicity and circannual levels of LH, FSH, and testosterone in normal and castrated male, white-tailed deer

To establish the relation between photoperiodicity and the levels of LH, FSH, and testosterone (T) in plasma, three intact and three castrated adult male white-tailed deer were sampled once a month for 2-3 years. The rang of average LH levels in controls varied between 0.8 and 2.0 ng/mL; the levels in castrates were considerably higher, 3.4 to 8.9 ng/mL. Average levels of FSH varied in controls between 25 and 112 ng/mL and in castrates between 141 and 240 ng/mL. A significant correlation between the seasonal time course of LH and FSH was found in castrated, but not in intact bucks. In castrates both gonadotropins exhibit two major elevations coinciding with spring and fall equinoxes in March and September. The seasonal time course of FSH in castrates correlates highly with seasonal levels of FSH in controls. However, the time course of the LH curve in controls is substantially different from the curve in castrates, presumably owing to feedback mechanisms. A possible role of testicular estradiol in this feedback is discussed. In controls, peak T levels are reached in December, i.e., 3 months after maximum levels of FSH and 5 months after peak levels of LH were detected. It appears that male deer undergo two periods of reproductive stimulation (one in the spring, the other in the fall). However, the organism responds with the full range of gonadal and behavioral mechanisms leading to the initiation of the rut only during the fall.