Heat stress associated with aerosol PPE and its impact.

BACKGROUND: Aerosol personal protective equipment (PPE) is subjectively reported to negatively impact healthcare workers' performance and well-being, but this has not been assessed objectively. AIMS: This randomized controlled crossover study aimed to quantify the heat stress associated with aerosol PPE and to investigate its impact upon mood, cognitive and motor function, and task performance. METHODS: Sixteen healthy, young, lean participants (eight males) undertook an exercise protocol, which simulated the metabolic expenditure of hospital work: once wearing aerosol PPE (PPE visit) and once wearing standard surgical attire (control visit). Participants walked on a treadmill for 2 h followed by 30-min rest. Core temperature, heart rate, urine specific gravity, weight, grip strength, mood (Bond-Lader scale) and task performance (Intubation of a Manikin) were recorded. Values are between-visit mean (standard deviation) differences. RESULTS: On the PPE visit core temperature (+0.2 (0.3)°C; P < 0.01), heart rate (+12 (13) bpm; P < 0.001), urine specific gravity (+0.003 (0.005); P < 0.05) and intubation task time (+50 (81) s; P < 0.01) were greater than on the control visit; and alertness (-14 (21) mm; P < 0.001), contentment (-14 (15) mm; P < 0.001) and grip strength (-4 (4) N; P < 0.01) were less. CONCLUSIONS: This study demonstrates that wearing aerosol PPE in a simulated hospital environment results in heat exhaustion and has a negative impact upon mood, motor function, and task performance. Whilst wearing PPE is important to prevent disease transmission, strategies should be developed to limit its impact upon healthcare workers' performance and well-being.

An open-source musculoskeletal model of the lumbar spine and lower limbs: a validation for movements of the lumbar spine.

Musculoskeletal models of the lumbar spine have been developed with varying levels of detail for a wide range of clinical applications. Providing consistency is ensured throughout the modelling approach, these models can be combined with other computational models and be used in predictive modelling studies to investigate bone health deterioration and the associated fracture risk. To provide precise physiological loading conditions for such predictive modelling studies, a new full-body musculoskeletal model including a detailed and consistent representation of the lower limbs and the lumbar spine was developed. The model was assessed against in vivo measurements from the literature for a range of spine movements representative of daily living activities. Comparison between model estimations and electromyography recordings was also made for a range of lifting tasks. This new musculoskeletal model will provide a comprehensive physiological mechanical environment for future predictive finite element modelling studies on bone structural adaptation. It is freely available on https://simtk.org/projects/llsm/.

Reliability and minimal detectable change of the 'Imperial Spine' marker set for the evaluation of spinal and lower limb kinematics in adults.

OBJECTIVES: As a step towards the comprehensive evaluation of movement in patients with low back pain, the aim of this study is to design a marker set (three rigid segment spine, pelvic and lower limb model) and evaluate the reliability and minimal detectable change (MDC) of this marker set in healthy adults during gait and sit to stand (STS) tasks using three dimensional motion capture. RESULTS: The 'Imperial Spine' marker set was used to assess relative peak angles during gait and STS tasks using the minimum recommended sample size (n = 10) for reliability studies with minimum Intraclass Correlation Coefficient (ICC) of 0.70, optimum ICC 0.90 and 9 trials replicated per subject per task. Intra- and inter-tester reliability between an experienced and inexperienced user was examined. ICC, mean, standard error (SEM), Bland Altman 95% limits of agreement (LOA) and MDC were computed. ICC values demonstrated excellent intra- and inter-tester reliability in both tasks, particularly in the sagittal plane (majority ICCs > 0.80). SEM measurements were lower in gait (0.8-5.5°) than STS tasks (1°-12.6°) as were MDC values. LOA demonstrated good agreement. The 'Imperial Spine' marker set is reliable for use in healthy adults during functional tasks. Future evaluation in patients is required.

Biomechanical determinants of elite rowing technique and performance.

In rowing, the parameters of injury, performance, and technique are all interrelated and in dynamic equilibrium. Whilst rowing requires extreme physical strength and endurance, a high level of skill and technique is essential to enable an effective transfer of power through the rowing sequence. This study aimed to determine discrete aspects of rowing technique, which strongly influence foot force production and asymmetries at the foot-stretchers, as these are biomechanical parameters often associated with performance and injury risk. Twenty elite female rowers performed an incremental rowing test on an instrumented rowing ergometer, which measured force at the handle and foot-stretchers, while three-dimensional kinematic recordings of the ankle, knee, hip, and lumbar-pelvic joints were made. Multiple regression analyses identified hip kinematics as a key predictor of foot force output (R(2) = 0.48), whereas knee and lumbar-pelvic kinematics were the main determinants in optimizing the horizontal foot force component (R(2) = .41). Bilateral asymmetries of the foot-stretchers were also seen to significantly influence lumbar-pelvic kinematics (R(2) = 0.43) and pelvic twisting (R(2) = 0.32) during the rowing stroke. These results provide biomechanical evidence toward aspects of technique that can be modified to optimize force output and performance, which can be of direct benefit to coaches and athletes.

Impaired neural drive in patients with low back pain.

BACKGROUND: Control of trunk movement relies on the integration between central neuronal circuits and peripheral skeletomuscular activities and it can be altered by pain. There is increasing evidence that there are deficits within the central nervous system controlling the trunk muscles in people with low back pain (LBP). However, it is unclear how LBP impacts upon neural drive to back muscles at different levels of voluntary contraction. Therefore, the purpose of this study was to investigate if neural drive is impaired in these patients. METHODS: Seventeen patients with LBP and 11 healthy controls were recruited. Bilateral electromyographic (EMG) recordings were obtained from the erector spinae (ES) muscles at two vertebral levels (T12 and L4). Participants performed a series of brief isometric back extensions (50-100% maximum voluntary contraction - MVC), during which transcranial magnetic stimulation was delivered. The size of the evoked (superimposed) twitch was measured using dynamometry. RESULTS: The size of the superimposed twitch decreased linearly with increasing contraction strength in the controls; however, this linear relationship was not observed in the patients. Additionally, patients had larger superimposed twitches and longer time-to-peak amplitudes during MVCs than those observed in controls. Furthermore, patients had lower MVC and root-mean-square EMG activity of ES muscles during MVCs. CONCLUSIONS: A decline of central neural drive to the back muscles at high level of voluntary contraction was observed in patients with LBP. These results suggest that it might be pertinent to include neuromuscular facilitation programmes and therapeutic exercise utilizing high voluntary contractions for patients with LBP.

The pathogenesis of degeneration of the intervertebral disc and emerging therapies in the management of back pain.

This article reviews the current knowledge of the intervertebral disc (IVD) and its association with low back pain (LBP). The normal IVD is a largely avascular and aneural structure with a high water content, its nutrients mainly diffusing through the end plates. IVD degeneration occurs when its cells die or become dysfunctional, notably in an acidic environment. In the process of degeneration, the IVD becomes dehydrated and vascularised, and there is an ingrowth of nerves. Although not universally the case, the altered physiology of the IVD is believed to precede or be associated with many clinical symptoms or conditions including low back and/or lower limb pain, paraesthesia, spinal stenosis and disc herniation. New treatment options have been developed in recent years. These include biological therapies and novel surgical techniques (such as total disc replacement), although many of these are still in their experimental phase. Central to developing further methods of treatment is the need for effective ways in which to assess patients and measure their outcomes. However, significant difficulties remain and it is therefore an appropriate time to be further investigating the scientific basis of and treatment of LBP.

Patients' views on an education booklet following spinal surgery.

PURPOSE: This study evaluated an evidence-based education booklet developed for patients undergoing spinal surgery which was used as a treatment intervention in a multi-centre, factorial, randomised controlled trial (FASTER: Function after spinal treatment, exercise and rehabilitation) investigating the post-operative management of spinal surgery patients. This study sought to determine the acceptability and content of the booklet to patients. METHODS: Patients receiving the educational booklet before discharge from hospital as part of the FASTER study were asked to complete an evaluation, which rated the booklet "Your Back Operation" with regard to content, information, usability, etc. using forced and open questions. This assessment was conducted at the same time as the initial 6-week post-operative review performed as part of the larger study. RESULTS: Therefore, 97% of the 117 trial participants who returned their 6-week evaluation and randomised to receive a booklet returned their questionnaire. The booklet was highly rated receiving an overall rating of 7 or more out of 10 from 101/111 (91%), and high ratings for content, readability and information. The booklet's key messages were clear to the majority of patients; however, many patients highlighted deficiencies with respect to content particularly in relation to wound care and exercise. CONCLUSIONS: Patients valued the booklet and rated its content highly. Many suggested that the booklet be developed further and there was a clear desire for specific exercises to be included even though there is no evidence to support specific exercise prescription.

Body-worn sensor design: what do patients and clinicians want?

User preferences need to be taken into account in order to be able to design devices that will gain acceptance both in a clinical and home setting. Sensor systems become redundant if patients or clinicians do not want to work with them. The aim of this systematic review was to determine both patients' and clinicians' preferences for non-invasive body-worn sensor systems. A search for relevant articles and conference proceedings was performed using MEDLINE, EMBASE, Current Contents Connect, and EEEI explore. In total 843 papers were identified of which only 11 studies were deemed suitable for inclusion. A range of different clinically relevant user groups were included. The key user preferences were that a body-worn sensor system should be compact, embedded and simple to operate and maintain. It also should not affect daily behavior nor seek to directly replace a health care professional. It became apparent that despite the importance of user preferences, they are rarely considered and as such there is a lack of high-quality studies in this area. We therefore would like to encourage researchers to focus on the implications of user preferences when designing wearable sensor systems.

Degeneration of the extensor muscle group in a surgical low back and leg pain population.

The spinal muscles have received great attention in low back pain (LBP) with suggestions of a de-conditioning syndrome. It is not known whether it is a long or short term consequence of LBP. This study explored the cross section area (CSA) and muscle quality of the spinal extensor group in LBP patients referred to a spinal clinic. MRI scans of 100 annoymised patients were retrospectively reviewed; sagittal and transverse (from levels L3-5) images were archived and analysed to determine CSA and levels of fat infiltration of the extensor muscle groups. Forty six patients had spinal stenosis (28 males, 18 females, mean age 66 ± 14.2 years) and 54 had a disc prolapse (28 males, 26 females, mean age 50 ± 12.9 years). CSA was significantly smaller in the stenotics at both L3/4 and L4/5. Patients presenting with leg pain and a disc herniation had a significantly smaller CSA (p < 0.01) at L3/4 and L4/5 levels. Fat infiltration was present in both groups but was significantly greater in the stenotic group (p < 0.01) and was present at a similar degree at all spinal levels. Multiple regression analysis confirmed that reduced CSA was linked to leg pain (p < 0.01) and age was linked with fat infiltration (p < 0.01). Future work should explore the extent of such changes in an age and sex matched control population with no current back pain or sciatica.

Predicting the lumbosacral joint centre location from palpable anatomical landmarks.

The kinematics of the lumbar spine have previously been described by considering the bearing of the pelvis and lower back. However earlier studies have not described an intersegmental angle measured about a single point; which is necessary for investigation into movement, posture and balance, and lower back pain and injury. This study used computed tomography (CT) scans of 16 pelves to determine the location of palpable bony landmarks, and the junction of the fifth lumbar and first sacral vertebrae within a pelvis axis system. Data were used to derive equations which express the three-dimensional location of the lumbosacral joint centre as an offset from palpable surface landmarks. The magnitude of X, Y, Z offsets was controlled using individual pelvic geometry, and robustness and repeatability of the method was assessed. Regression equations provided the location of the lumbosacral junction to within 8.2mm (+/- 3.4mm) of its true coordinate. Leave-one-out analyses calculated equation coefficients using 15 of the original pelves, with the 16th acting as a control; average errors increased by 6.7 per cent (+/- 0.1 percent). To the authors' knowledge the current method is the most accurate non-invasive means of locating the lumbosacral junction and may be useful for constructing biomechanical models.

Modulation of weight off-loading level over body-weight supported locomotion training.

With the evolution of robotic systems to facilitate overground walking rehabilitation, it is important to understand the effect of robotic-aided body-weight supported loading on lower limb muscle activity, if we are to optimize neuromotor recovery. To achieve this objective, we have collected and studied electromyography (EMG) data from key muscles in the lower extremity from healthy subjects walking over a wide range of body-weight off-loading levels as provided by a bespoke gait robot. By examining the impact of body-weight off-loading, it was found that muscle activation patterns were sensitive to the level of off-loading. In addition, a large off-loading might introduce disturbance of muscle activation pattern, led to a wider range of motion in terms of dorsiflexion/plantarflexion. Therefore, any future overground training machine should be enhanced to exclude unnecessary effect of body off-loading in securing the sustaining upright posture and providing assist-as-needed BWS over gait rehabilitation.

Function after spinal treatment, exercise and rehabilitation (FASTER): improving the functional outcome of spinal surgery.

BACKGROUND: The life-time incidence of low back pain is high and diagnoses of spinal stenosis and disc prolapse are increasing. Consequently, there is a steady rise in surgical interventions for these conditions. Current evidence suggests that while the success of surgery is incomplete, it is superior to conservative interventions. A recent survey indicates that there are large differences in the type and intensity of rehabilitation, if any, provided after spinal surgery as well as in the restrictions and advice given to patients in the post-operative period. This trial will test the hypothesis that functional outcome following two common spinal operations can be improved by a programme of post-operative rehabilitation that combines professional support and advice with graded active exercise and/or an educational booklet based on evidence-based messages and advice. METHODS/DESIGN: The study design is a multi-centre, factorial, randomised controlled trial with patients stratified by surgeon and operative procedure. The trial will compare the effectiveness and cost-effectiveness of a rehabilitation programme and an education booklet for the postoperative management of patients undergoing discectomy or lateral nerve root decompression, each compared with "usual care"using a 2 x 2 factorial design. The trial will create 4 sub-groups; rehabilitation-only, booklet-only, rehabilitation-plus-booklet, and usual care only. The trial aims to recruit 344 patients, which equates to 86 patients in each of the four sub-groups. All patients will be assessed for functional ability (through the Oswestry Disability Index - a disease specific functional questionnaire), pain (using visual analogue scales), and satisfaction pre-operatively and then at 6 weeks, 3, 6 and 9 months and 1 year post-operatively. This will be complemented by a formal analysis of cost-effectiveness. DISCUSSION: This trial will determine whether the outcome of spinal surgery can be enhanced by either a post-operative rehabilitation programme or an evidence-based advice booklet or a combination of the two and as such will contribute to our knowledge on how to manage spinal surgery patients in the post-operative period.

Lower limb involvement in spinal function and low back pain.

AIM: To evaluate evidence for involvement of the lower limb in spinal function and low back pain (LBP). DESIGN: A hypothesis based on a critical review of the relevant biomechanical and clinical literature. RESULTS: The spine resembles an inverted pendulum that supports the weight of the upper body; its stability requires a moving base that is provided by the joints of the lower limb, especially the hip. However, the sacroiliac joints are unlikely to be important for spinal function. The changing pattern of gait and development of lumbar lordosis, in early childhood, provide evidence for the inter-dependence of spinal curvature and lower limb action. Clinical signs associated with LBP may be associated with an inability to rotate the trunk about the hips. These include disorientation of the pelvis and weakness or tightness of muscles around the hip. The "sway back" posture seen in LBP involves flexion of the hip, knee and ankle to compensate for abdominal and back muscle weakness. CONCLUSIONS: In order to understand the varied clinical presentation of LBP patients, the function of the spine should be considered in the context of the whole body, especially the lower limb.

In-House Monitoring of low back pain related disability (IMPAIRED).

Preventive care, healthcare management and a working population are areas of growing emphasis in industrialized countries. Recent exponential growth in technological developments has made developing wearable monitoring systems feasible. Chronic Low Back Pain (CLBP) is a leading cause of disability with staggering economic costs and severe psychological and social consequences. A principal issue is the assessment of LBP severity at a single point of time during clinic visits rather than through continuous monitoring. This paper presents the project In-House Monitoring of Low-Back-Pain Related Disability (IMPAIRED) which aims to design and develop a multi-sensor wearable prototype to monitor movement of the lumbar spine and pelvis, sleep disturbance (circadian rhythm), as well as muscle fatigue and activity pattern. We have identified relevant movements correlating to disability associated with LBP, evaluated the suitability of inertial sensors to monitor the expected range of movement and proposed a sensor placement map.

The outcome of spinal decompression surgery 5 years on.

Decompression surgery is an increasingly common operation for the treatment of lumbar spinal stenosis. Although good relief from leg pain is expected after surgery, long term results of pain relief and function are more uncertain. This study prospectively followed a cohort of patients presenting with the signs and symptoms of spinal stenosis, who underwent decompression surgery to ascertain the long term outcome with respect to pain and function using visual analogue pain scores, the Oswestry Disability Index, and the Short Form 36, a general health questionnaire. From an initial pool of 84 recruited patients, 7 withdrew from surgical intervention; of the remaining 77, 51 (66%) returned for follow up assessments at 5 years. In these responders, a significant improvement was observed in back and leg pain, which was sustained for at least 1 year (P < 0.01). A significant improvement was also seen in physical function (P < 0.05) as assessed by Oswestry and SF-36. Although an initial improvement was noted in social function, this was not observed at 5 years. This study has demonstrated that decompression surgery is successful in relieving symptoms of lumbar spinal stenosis. Physical function, back and leg pain are significantly improved after 5 years but initial significant improvements in social function diminish over time.

The development of an evidence-based patient booklet for patients undergoing lumbar discectomy and un-instrumented decompression.

Post-operative management after lumbar surgery is inconsistent leading to uncertainty amongst surgeons and patients about post-operative restrictions, reactivation, and return to work. This study aimed to review the evidence on post-operative management, with a view to developing evidence-based messages for a patient booklet on post-operative management after lumbar discectomy or un-instrumented decompression. A systematic literature search produced a best-evidence synthesis of information and advice on post-operative restrictions, activation, rehabilitation, and expectations about outcomes. Evidence statements were extracted and developed into patient-centred messages for an educational booklet. The draft text was evaluated by peer and patient review. The literature review found little evidence for post-operative activity restrictions, and a strong case for an early active approach to post-operative management. The booklet was built around key messages derived from the literature review and aimed to reduce uncertainty, promote positive beliefs, encourage early reactivation, and provide practical advice on self-management. Feedback from the evaluations were favourable from both review groups, suggesting that this evidence-based approach to management is acceptable and it has clinical potential.

Establishment of a protocol to test fatigue of the trunk muscles.

BACKGROUND: Muscle fatigue has high relevance in human performance yet little research has evaluated how it should be assessed. OBJECTIVE: To perform a pilot study to identify suitable methods of generating and assessing fatigue of the trunk flexor and extensor muscles. METHODS: Sixteen university rugby players (mean (SEM) age 21.9 (0.2) years) were recruited and subjected to four protocols (A, B, C, D), separated by a week to allow recovery, with peak torque being recorded during each test: A, isokinetic measurements before and after fatigue, with a 10 repetition isokinetic fatigue period; B, isokinetic measurements before and after fatigue with a 45 second isometric fatigue period; C, isometric measurements before and after fatigue with a 10 repetition isokinetic fatigue period; D, isometric measurements before and after fatigue with a 45 second isometric fatigue period. All were conducted during flexion and extension of the trunk on the Cybex Norm Isokinetic Dynamometer trunk flexion-extension unit. RESULTS: All subjects completed all four protocols. Fatigue induction appeared more effective in flexion than extension. Significant differences in mean peak torque before and after fatigue were seen in protocols A, B, and D in flexion and only in protocol D for extension. In flexion, protocol D produced the greatest fatigue, peak torque being 16.2% less after than before fatigue, suggesting greatest sensitivity. CONCLUSIONS: Protocol D, which incorporates isometric testing and fatigue protocols, appears to be able to produce fatigue most effectively, and therefore may provide the most valid assessment of fatigue in the trunk flexor and extensor muscles.

Motor neurone excitability in back muscles assessed using mechanically evoked reflexes in spinal cord injured patients.

OBJECTIVE: The clinical and functional assessment of back muscles in human spinal cord injury (SCI) has received little attention. The aim of this study was to develop a method to assess the level of a thoracic spinal cord lesion based on the reflex activation of back muscles. METHODS: In 11 control subjects and in 12 subjects with clinically complete thoracic SCI (T2-T12), either a spinous process or an erector spinae muscle was prodded to elicit short latency reflexes recorded electromyographically at the spinal level of stimulation. An electromagnetic servo, attached to a blunt probe, applied stimuli at a frequency of 1 Hz and amplitude of 3 mm. Two trials of 50 mechanical prods were conducted at each site. RESULTS: Reflexes were evoked in control subjects in 82% of trials when the spinous process was prodded, and in 80% of trials when the muscle was prodded. In contrast, reflexes in SCI subjects could be elicited in 90-100% of trials two segments either above or below the lesion. Reflex responses in control subjects had a mean (SEM) latency of 5.72 (0.53) ms when the spinous process was prodded, and 5.42 (0.42) ms when the muscle was prodded. In the SCI subjects, responses had slightly (but insignificantly) longer latencies both above and below the lesion to either stimulus. The amplitude of reflex responses, expressed as a percentage of the background EMG, was on average 2-3 times larger at the three vertebral levels spanning the lesion in SCI subjects than at sites above or below the lesion or at any level in control subjects. CONCLUSION: We propose that the size of these mechanically evoked reflexes may be useful in determining the level of thoracic SCI. Furthermore, the reflexes might provide a valuable tool with which to monitor recovery after an intervention to repair or improve function of a damaged spinal cord.

A comparison of rowing technique at different stroke rates: a description of sequencing, force production and kinematics.

Low back pain is the commonest musculoskeletal complaint in rowers. Research into the relationship between rowing technique, the forces generated during the rowing stroke and the kinematics of spinal motion are increasing, but to date none have investigated the impact of different rowing intensities on this relationship. A technique has been developed using an electromagnetic motion system and strain gauge instrumented load cell to measure spinal and pelvic motion and force generated at the handle during rowing on an exercise rowing ergometer. Using this technique ten collegiate male rowers (mean age 22.1+/-2.8 years) from local rowing clubs were investigated. The test protocol consisted of rowing on an ergometer at three different stroke ratings; 17-20 strokes per minute; 24-28 strokes per minute; and 28-36 strokes per minute. Each rating was held for four minutes, with a five-minute rest between each rating. Marked changes in the force output curve and lumbopelvic kinematics were observed at the different rowing intensities. Although there was no change in the magnitude of peak torque generated during the different rating, there was a marked shift in when this occurred during the stroke. In terms of kinematic changes, these centred around changes in pelvic rotation at the catch and finish stages of the stroke with significantly less anterior rotation occurring at the catch position at higher rowing intensities. To conclude, this study suggests that rowing kinematics and force profiles do change at higher rowing intensities. These changes may be an important factor with respect to injury mechanisms, however, further work is required at an elite level.