Motor control during an active straight leg raise in pain free and chronic pelvic girdle pain subjects

Aberrant motor control strategies have been identified in chronic pelvic girdle pain (PGP) subjects. It has been proposed that aberrant motor control strategies could provide a mechanism for ongoing pain and disability in these subjects. This thesis consists of a series of studies that have investigated motor control strategies during the active straight leg raise (ASLR) test, under various loading conditions, in pain free nulliparous female subjects (n=14) and female subjects with chronic PGP (n=12). Clinical examination of the chronic PGP subjects had identified the SIJ and surrounding structures as the primary source of symptoms. Heaviness of the leg (+/- pain) when the pain subjects performing the ASLR was relieved in all the pain subjects with the addition of manual pelvic compression during the ASLR, consistent with a pain disorder associated with impaired force closure mechanism.Phase of respiration was monitored with the pneumotach. Electromyography was recorded bilaterally from internal obliquus abdominis (IO), external obliquus abdominis, rectus abdominis, anterior scaleni and rectus femoris as well as the right chest wall (CW). Intra-abdominal pressure (IAP) and intra-thoracic pressure were measured with a nasogastric catheter attached to custom-made pressure transducer equipment. Downward pressure of the non-lifted leg during an ASLR was recorded with an inflated pad linked to a pressure transducer placed under the heel. Data for these variables were collected in a custom designed data acquisition program. A separate custom designed program was used for data processing. Additionally, motion of the pelvic floor (PF) was monitored with a real-time ultrasound unit and recorded to digital video for manual processing.Study 1: Motor control patterns during an active straight leg raise in pain free subjects Pain free subjects demonstrated greater muscle activation of the abdominal and CW ipsilateral to the side the ASLR was performed on. This effect was most pronounced local to the pelvis in IO. This muscle pattern was associated with a small increase in IAP. Although there was an overall commonality in the motor control patterns, individual variation was apparent. This study contradicted the theory of anterior diagonal slings for the provision of pelvic stability/force closure during the ASLR. The findings of this study highlights the flexibility of the neuromuscular system in controlling load transference during an ASLR, and the plastic nature of the abdominal cylinder.Study 2: Motor control patterns during an active straight leg raise in chronic pelvic girdle pain subjects In contrast to pain free subjects, chronic PGP subjects demonstrated bracing of the abdominal wall and right CW during an ASLR on the symptomatic side of the body. This was associated with higher levels of IAP and increased downward movement of the PF. Increased levels of IAP could have negative consequences and be provocative of pain. The findings from this study support the notion that aberrant motor activation patterns exist in this group of subjects.Study 3: The effect of increased physical load during an active straight leg raise in pain free subjects When performing an ASLR with additional physical load around the ankle, pain free subjects demonstrated increased muscle activation levels compared to an ASLR without additional load, with higher levels of IAP. Greater ipsilateral IO activation observed during an ASLR was maintained during the loaded ASLR, unlike the symmetrical bracing pattern observed in PGP subjects. This adds support to the notion that PGP subjects have aberrant motor control patterns during an ASLR, not represented solely by the increased effort of lifting the leg.Study 4: The effect of resisted inspiration during an active straight leg raise in pain free subjects Pain free subjects performed an ASLR while also breathing with inspiratory resistance, to simultaneously provide a stability and respiratory challenge upon the neuromuscular system. Motor activation in the abdominal wall was highlighted by a cumulative increase in motor activation when performing the ASLR with inspiratory resistance compared to performing these tasks in isolation. Despite this general increase in activation, a pattern of greater IO activity on the side of the leg lift observed during an ASLR was preserved when inspiratory resistance was added to the ASLR. Intra-abdominal pressure demonstrated an incremental increase similar to the increase in muscle activity. This confirms that pain free subjects are able to adapt to multiple demands of an ASLR and inspiratory resistance by an accumulative summation of the patterns utilised when these tasks are performed independently.Study 5: Non-uniform motor control changes with manually applied pelvic compression during an active straight leg raise in chronic pelvic girdle pain subjects The PGP subjects performed an ASLR with the addition of manual pelvic compression. The hypothesis that this would reduce muscle activation levels and IAP was not supported. Rather, trends for either trunk muscle facilitation or inhibition were identified. Trunk muscle facilitation was associated with higher levels of IAP, whereas motor inhibition was associated with lower levels of IAP. These findings suggest a potential for different underlying mechanism associated with the chronic PGP disorder in these subjects and variable responses to pelvic compression.While a number of the statistical analyses were significant suggesting some consistency in motor patterns, visual inspection of the data demonstrated individual variations in the motor control strategies in both pain free and chronic PGP subjects.Taken together, these findings demonstrate that: * Pain free subjects adopt a predominant pattern of greater motor activation ipsilateral to the side of the leg lift during an ASLR, an ASLR with additional physical load and an ASLR performed with inspiratory resistance. Within this commonality in motor control, individual variations exist. * Chronic PGP subjects do not demonstrate greater ipsilateral activation during an ASLR on the symptomatic side. Instead they adopt a bilateral bracing/splinting motor control pattern with increased IAP.It is hypothesised that: The aberrant motor control patterns observed in these chronic PGP subjects may be maladaptive in nature. These aberrant patterns may have negative consequences on pelvic loading and stability, respiration, continence, pain and disability. The findings of this thesis are consistent with complex underlying mechanisms driving chronic pelvic girdle pain disorders, and suggest that multiple factors have the potential to influence motor control strategies in these subjects. These findings may have implications for management of chronic PGP disorders, highlighting the need for individualised programs that attempt to normalise aberrant motor control strategies.This thesis has added substantially to the knowledge of motor control in chronic PGP disorders, a research area in its infancy compared to the investigation of motor control in the lumbar and cervical regions of the spine. Now that PGP has been recognised as a separate diagnostic entity to LBP, greater understanding of this region is essential for the identification of sub-groups within the diagnosis of PGP, and for the development of specific intervention strategies that target the underlying pain mechanisms driving these disorders

Low Back Pain and Comorbidity Clusters at 17 Years of Age: A Cross-sectional Examination of Health-Related Quality of Life and Specific Low Back Pain Impacts

Purpose: Comorbidities in adults negatively affect the course of low back pain (LBP). Little is known of the presence and/or impact of LBP comorbidities in adolescents. Methods: Subjects from the Raine Study cohort at age 17 years (n = 1,391) provided self-report of diagnosed medical conditions/health complaints, health-related quality of life (36-Item Short Form Health Survey [SF-36]), lifetime experience of LBP, and specific LBP impacts (taking medication, missing school/work, interference with normal/physical activities). Latent class analysis was used to estimate clusters of comorbidities based on diagnosed disorders. Profiles of SF-36 and impact were examined between clusters. Results: Four distinct comorbidity clusters were identified: cluster 1: Low probability of diagnosed LBP or any other medical condition (79.7%); cluster 2: High probability of diagnosed LBP and neck/shoulder pain, but a low probability of other diagnosed health conditions (9.6%); cluster 3: Moderate probability of diagnosed LBP and high probability of diagnosed anxiety and depression (6.9%); cluster 4: Moderate probability of diagnosed LBP and high probability of diagnosed behavioral and attention disorders (3.8%). The clusters had different SF-36 and LBP impact profiles, with clusters 3 and 4 having poorer SF-36 scores, and clusters 2 to 4 having greater risk for specific LBP impacts, than cluster 1. Conclusions: Identified comorbidity clusters support adolescent and adult studies reporting associations between LBP, other pain areas, psychological disorders, and disability. Tracking these clusters into adulthood may provide insight into health care utilization in later life, whereas identification of these individuals early in the life span may help optimize intervention opportunities

Knowledge and Use of The ‘Clinical Framework For the Delivery of Health Services’ in Western Australia: Summary report of a survey of Workers’ Compensation stakeholders

The Clinical Framework for the Delivery of Health Services (Clinical Framework) provides guiding principles for the management of injured works based on contemporary evidence. As part of an “Injured Worker Symposium” hosted by Curtin University in March this year, 161 stakeholders from variety of roles, who deal with injured workers in the Western Australian Workers’ Compensation sector, completed an online questionnaire. This questionnaire collected stakeholder perspectives regarding the Clinical Framework, barriers and enablers for timely recovery of injured workers, and understanding of the biopsychosocial management of workers with musculoskeletal pain disorders. The study found that 43% of respondents were ‘not familiar’ with the Clinical Framework. Another 32% were only ‘somewhat familiar’. This suggests that further work is required to educate stake holders on the existence and utility of the Clinical Framework. There was strong agreement among the different stakeholder groups regarding the key importance of communication between stakeholders and the employer-employee relationship to the recovery of injured workers. While this is a preliminary survey and the results need to be interpreted with some caution, the findings of the survey support that further stakeholder education is required in a number of areas related to the Clinical Framework. This document provides a summary and interpretation of the survey results and recommendations for further research and education, based on the findings of the study

Trajectories of childhood body mass index are associated with adolescent sagittal standing posture

Objectives. To identify distinct age-related trajectory classes of body mass index (BMI) z-scores from childhood to adolescence, and to examine the association of these trajectories with measures of standing sagittal spinal alignment at 14 years of age. Methods. Adolescents participating in the Western Australian Pregnancy Cohort (Raine) Study contributed data to the study (n=1 373). Age- and gender-specific z-scores for BMI were obtained from height and weight at the ages of 3, 5, 10 and 14 years. Latent class group analysis was used to identify six distinct trajectory classes of BMI z-score. At the age of 14 years, adolescents were categorised into one of four subgroups of sagittal spinal posture using k-means cluster analysis of photographic measures of lumbar lordosis, thoracic kyphosis and trunk sway. Regression modeling was used to assess the relationship between postural angles and subgroups, and different BMI trajectory classes, adjusting for gender. Results. Six trajectory classes of BMI z-score were estimated: Very Low (4%), Low (24%), Average (34%), Ascending (6%), Moderate High (26%) and Very High (6%). The proportions of postural subgroups at age 14 were; Neutral (29%), Flat (22%), Sway (27%) and Hyperlordotic (22%). BMI trajectory class was strongly associated with postural subgroup, with significantly higher proportions of adolescents in the Very High, High and Ascending BMI trajectory classes displaying a Hyperlordotic or Sway posture than a Neutral posture at age 14. Conclusions. This prospective study provides evidence that childhood obesity, and how it develops, is associated with standing sagittal postural alignment in adolescence

Disturbed body perception, reduced sleep, and kinesiophobia in subjects with pregnancy-related persistent lumbopelvic pain and moderate levels of disability: An exploratory study

Background: For a small but significant group, pregnancy-related lumbopelvic pain may become persistent. While multiple factors may contribute to disability in this group, previous studies have not investigated sleep impairments, body perception or mindfulness as potential factors associated with disability post-partum. Objectives: To compare women experiencing no pain post-pregnancy with those experiencing pregnancy-related persistent lumbopelvic pain (either low- or high-level disability) across multiple biopsychosocial domains. Design: Cross-sectional Methods: Participants completed questionnaires for thorough profiling of factors thought to be important in pregnancy-related lumbopelvic pain. Specific measures were the Urinary Distress Inventory, Medical Outcomes Study Sleep Scale, Back Beliefs Questionnaire, Tampa Scale for Kinesiophobia, Depression Anxiety Stress Scale, Coping Strategies Questionnaire, Pain Catastrophising Scale, The Fremantle Back Awareness Questionnaire and the Mindful Attention Awareness Scale. Women where categorised into three groups; pain free (n = 26), mild disability (n = 12) and moderate disability (n = 12) (based on Oswestry Disability Index scores). Non-parametric group comparisons were used to compare groups across the profiling variables. Results: Differences were identified for kinesiophobia (p = 0.03), body perception (p = 0.02), sleep quantity (p \u3c 0.01) and sleep adequacy (p = 0.02). Generally subjects in the moderate disability group had more negative findings for these variables. Conclusion: Disturbances in body-perception, sleep and elevated kinesiophobia were found in pregnancy-related lumbopelvic pain subjects with moderate disability, factors previously linked to persistent low back pain. The cross-sectional nature of this study does not allow for identification of directional pathways between factors. The results support the consideration of these factors in the assessment and management of pregnancy-related lumbopelvic pain

Urogenital symptoms: prevalence, bother, associations and impact in 22 year-old women of the Raine Study

Introduction and hypothesis: Urogenital symptoms are prevalent in older women, but there is little data available on the prevalence, bother, impact and associations with low back pain (LBP), obesity, parity, mental health (MH) and quality of life (QOL) in young women. Our aim was to determine the prevalence, bother and impact of urogenital symptoms and to explore associations with LBP, obesity, parity, MH and QOL in 22 year-old women. Methods: This was a cross-sectional evaluation using data collected from 588 women in the Raine Study, a pregnancy cohort in which participants have been regularly followed up from birth until 22 years. Data was analysed using descriptive statistics, univariate comparisons and linear regression models. Results: Prevalence of urogenital symptoms were stress urinary incontinence (SUI) 6.3%, mixed urinary incontinence (MUI) 11.5%, leakage of drops 5.8%, urge urinary incontinence (UUI) 5.3%, bothersome urinary frequency 41.5%, difficulty emptying 11.8% and urogenital pain 22.9%. Urinary frequency, MUI, difficulty emptying and urogenital pain were most bothersome, whilst difficulty emptying and urogenital pain were associated with greatest impact. Urinary frequency, SUI, leakage of drops, difficulty emptying and urogenital pain were associated with current LBP and LBP ever. Difficulty emptying and urogenital pain were associated with chronic LBP. Urogenital symptoms were not associated with obesity or parity. Women with urogenital symptoms had significantly poorer scores on the Mental Component Score of the Short Form Health Survey (SF)-12 and all aspects of the Depression Anxiety Stress Score. Conclusions: Urogenital symptoms are prevalent in young women, bothersome for some and are associated with LBP, poorer MH and reduced QOL

STarT Back Tool risk stratification is associated with changes in movement profile and sensory discrimination in low back pain: A study of 290 patients

Background: Investigation of movement and sensory profiles across STarT Back risk subgroups. Methods: A chronic low back pain cohort (n = 290) were classified as low, medium or high risk using the STarT Back Tool, and completed a repeated spinal bending task and quantitative sensory testing. Pain summation, time taken and the number of protective behaviours with repeated bending were measured. Sensory tests included two-point discrimination, temporal summation, pressure/thermal pain thresholds and conditioned pain modulation. Subgroups were profiled against movement and sensory variables. Results: The high-risk subgroup demonstrated greater pain summation following repeated forward bending (p < 0.001). The medium-risk subgroup demonstrated greater pain summation following repeated backward bending (p = 0.032). Medium- and high-risk subgroups demonstrated greater forward/backward bend time compared to the low-risk subgroup (p = 0.001, p = 0.005, respectively). Medium- and high-risk subgroups demonstrated a higher number of protective behaviours per forward bend compared to the low-risk subgroup (p = 0.008). For sensory variables, only two-point discrimination differed between subgroups, with medium- and high-risk subgroups demonstrating higher thresholds (p = 0.016). Conclusions: This study showed altered movement characteristics and sensory discrimination across SBT risk subgroups in people with CLBP. Membership of the high SBT risk subgroup was associated with greater pain and disability levels, greater pain summation following repeated bending, slower bending times, a greater number of protective behaviours during forward bending, and a higher TPD threshold. Treatment outcomes for higher risk SBT subgroups may be enhanced by interventions specifically targeting movement and sensory alterations. Significance: In 290 people with chronic low back pain movement profile and two-point discrimination threshold differed across risk subgroups defined by the STarT Back Tool. Conversely, pain sensitivity did not differ across these subgroups. These findings may add further guidance for targeted care in these subgroups

Brief biopsychosocially informed education can improve insurance workers' back pain beliefs: Implications for improving claims management behaviours

Background: Biopsychosocially informed education is associated with improved back pain beliefs and positive changes in health care practitioners’ practice behaviours. Objective: Assess the effect of this type of education for insurance workers who are important non-clinical stakeholders in the rehabilitation of injured workers. Methods: Insurance workers operating in the Western Australian workers’ compensation system underwent two, 1.5 hour sessions of biopsychosocially informed education focusing on understanding and identifying barriers to recovery of injured workers with musculoskeletal conditions. Back pain beliefs were assessed pre-education, immediately post-education and at three-month follow-up (n = 32). Self-reported and Injury Management Advisor-reported assessment of change in claims management behaviours were collected at the three-month follow-up. Results: There were positive changes in the Health Care Providers’ Pain and Impairment Relationship Scale (p = 0.009) and Back Beliefs Questionnaire (p = 0.049) immediately following the education that were sustained at three-month follow-up. Positive changes in claims management behaviours were supported by self-reported and Injury Management Advisor-reported data. Conclusion: This study provides preliminary support that a brief biopsychosocially informed education program can positively influence insurance workers’ beliefs regarding back pain, with concurrent positive changes in claims management behaviours. Further research is required to ascertain if these changes result in improved claims management outcomes

The association of adolescent spinal-pain-related absenteeism with early adulthood work absenteeism: A six-year follow-up data from a population-based cohort

Objectives Spinal (ie, back and neck) pain often develops as early as during adolescence and can set a trajectory for later life. However, whether early-life spinal-pain-related behavioral responses of missing school/work are predictive of future work absenteeism is yet unknown. We assessed the association of adolescent spinal-pain-related work or school absenteeism with early adulthood work absenteeism in a prospective population-based cohort. Methods Six year follow-up data from the Western Australian Pregnancy Cohort (Raine) study were used (N=476; with a 54% response rate). At age 17, participants reported spinal pain (using the Nordic questionnaire) and adolescent spinal-pain-related work/school absenteeism (with a single item question). Annual total and health-related work absenteeism was assessed with the Health and Work Performance questionnaire distributed in four quarterly text messages during the 23rd year of age. We modelled the association of adolescent spinal-pain-related absenteeism with work absenteeism during early adulthood, using negative binomial regression adjusting for sex, occupation and comorbidities. Results Participants with adolescent low-back or neck pain with work/school absenteeism reported higher total work absenteeism in early adulthood [148.7, standard deviation (SD) 243.4 hours/year], than those without pain [43.7 (SD 95.2) hours/year); incidence rate ratio 3.4 (95% CI 1.2-9.2)]. Comparable findings were found when considering low-back and neck separately, and when considering health-related absenteeism. Conclusions We found a more than three-fold higher risk of work absenteeism in early adulthood among those with adolescent spinal-pain-related absenteeism, compared to those without. These findings suggest that, to keep a sustainable workforce, pain prevention and management should focus on pain-related behaviors as early as in adolescence