Wim Dankaerts

The validity of O'Sullivan's classification system (CS) for a sub-group of NS-CLBP with motor control impairment (MCI): Overview of a series of studies and review of the literature

Chronic Low Back Pain (LBP) remains a common, recalcitrant and costly problem for the individual sufferer and for society. Effective treatments that reduce the social and economic burden have yet to be established for the majority of chronic LBP cases. Lack of evidence for specific interventions has been blamed on the heterogeneity of the chronic LBP population as well as a lack of a patient centred bio-psycho-social approach. This issue of heterogeneity has resulted in classification being considered the highest research priority in the area of chronic LBP. The potential for a wash-out effect caused by the heterogeneity of the chronic LBP populations sampled for randomised controlled clinical trials (RCTs), has driven the need for classifying patients with nonspecific chronic LBP. A summary of a series of studies is outlined in this review paper. They represent a comprehensive investigation into the validity of OSullivans proposed mechanism-based classification system (CS) for a sub-group of localized mechanically provoked nonspecific chronic LBP with motor control impairment (MCI). Further, the findings of these studies are discussed in relation to the relevant literature and the clinical implications arising are presented. Finally, the limitations of this research are outlined and recommendations for future research are made.

What do physiotherapists consider to be the best sitting spinal posture

While sitting is a common aggravating factor in low back pain (LBP), the best sitting posture remains unclear. This study investigated the perceptions of 295 physiotherapists in four different European countries on sitting posture. Physiotherapists selected their perceived best sitting posture from a sample of nine options that ranged from slumped to upright sitting, as well as completing the back beliefs questionnaire (BBQ). 85% of physiotherapists selected one of two postures as best, with one posture being selected significantly more frequently than the remainder (p < 0.05). Interestingly, these two most frequently selected postures were very different from each other. Those who selected the more upright sitting posture had more negative LBP beliefs on the BBQ (p < 0.05). The choice of best sitting posture also varied between countries (p < 0.05). Overall, disagreement remains on what constitutes a neutral spine posture, and what is the best sitting posture. Qualitative comments indicated that sitting postures which matched the natural shape of the spine, and appeared comfortable and/or relaxed without excessive muscle tone were often deemed advantageous. Further research on the perceptions of people with LBP on sitting posture are indicated.

Neutral lumbar spine sitting posture in pain-free subjects

Sitting is a common aggravating factor in low back pain (LBP), and re-education of sitting posture is a common aspect of LBP management. However, there is debate regarding what is an optimal sitting posture. This pilot study had 2 aims; to investigate whether pain-free subjects can be reliably positioned in a neutral sitting posture (slight lumbar lordosis and relaxed thorax); and to compare perceptions of neutral sitting posture to habitual sitting posture (HSP). The lower lumbar spine HSP of seventeen pain-free subjects was initially recorded. Subjects then assumed their own subjectively perceived ideal posture (SPIP). Finally, 2 testers independently positioned the subjects into a tester perceived neutral posture (TPNP). The inter-tester reliability of positioning in TPNP was very good (intraclass correlation coefficient (ICC) = 0.91, mean difference = 3% of range of motion). A repeated measures ANOVA revealed that HSP was significantly more flexed than both SPIP and TPNP (p <0.05). There was no significant difference between SPIP and TPNP (p > 0.05). HSP was more kyphotic than all other postures. This study suggests that pain-free subjects can be reliably positioned in a neutral lumbar sitting posture. Further investigation into the role of neutral sitting posture in LBP subjects is warranted.

The effect of dynamic sitting on the prevention and management of low back pain and low back discomfort: a systematic review

Dynamic sitting has been proposed to reduce low back pain (LBP) and/or low back discomfort (LBD) while sitting. This is supported by studies suggesting that subjects with LBP assume more static, sustained postures while sitting. This systematic review investigated the effect of dynamic sitting on LBP among subjects with LBP and the development of LBD among pain-free subjects. Electronic databases were searched by two independent assessors. All prospective studies which compared the effect of a dynamic sitting condition on LBP or LBD to another sitting condition were eligible, with no minimum follow-up period applied. The quality of the included studies was assessed using the PEDro scale. Seven high-quality studies were eligible, including five crossover studies and two randomised controlled trials. The results suggest there is currently no evidence to support the use of dynamic sitting as a stand-alone approach in the management of LBP. Practitioner Summary: This systematic review investigated the effect of dynamic sitting on LBP or LBD. Seven high-quality studies met the inclusion and exclusion criteria. Overall, the evidence suggests that dynamic sitting approaches are not effective as a stand-alone management approach for LBP.

Towards monitoring lumbo-pelvic posture in real-life situations: Concurrent validity of a novel posture monitor and a traditional laboratory-based motion analysis system

Many factors are associated with low back pain (LBP), including provocative spinal postures. Consequently, lumbo-pelvic posture is commonly assessed in LBP patients. A novel wireless monitor (BodyGuard™) can monitor lumbo-pelvic sagittal plane movements reliably, and has demonstrated concurrent validity during non-functional tasks. This study evaluated the concurrent validity of this monitor during functional tasks, as a precursor to LBP field studies. Twelve painfree participants performed a series of postural tasks (in sitting and standing) three times. Simultaneous postural measurements were obtained by the wireless monitor and a laboratory-based system (CODA™). Postural measurements were strongly correlated (r(s)xa0=xa00.88, r(2)xa0=xa00.78). The mean difference observed was small (<10% lumbo-pelvic ROM), however some tasks displayed greater error. The results support the concurrent validity of the wireless monitor for analysing lumbo-pelvic posture during functional tasks. Specific limitations of the monitor for certain postural tasks were identified, and should be considered before implementation in future field studies.

Lumbar posture and trunk muscle activation during a typing task when sitting on a novel dynamic ergonomic chair

Low back pain (LBP) is a common musculoskeletal disorder and prolonged sitting often aggravates LBP. A novel dynamic ergonomic chair (‘Back App’), which facilitates less hip flexion while sitting on an unstable base has been developed. This study compared lumbar posture and trunk muscle activation on this novel chair with a standard backless office chair. Twelve painfree participants completed a typing task on both chairs. Lumbar posture and trunk muscle activation were collected simultaneously and were analysed using paired t-tests. Sitting on the novel dynamic chair significantly (p < 0.05) reduced both lumbar flexion and the activation of one back muscle (Iliocostalis Lumborum pars Thoracis). The discomfort experienced was mild and was similar (p > 0.05) between chairs. Maintaining lordosis with less muscle activation during prolonged sitting could reduce the fatigue associated with upright sitting postures. Studies with longer sitting durations, and in people with LBP, are required. Practitioner Summary: Sitting on a novel dynamic chair resulted in less lumbar flexion and less back muscle activation than sitting on a standard backless office chair during a typing task among pain-free participants. Facilitating lordotic sitting with less muscle activation may reduce the fatigue and discomfort often associated with lordotic sitting postures.

The between-day and inter-rater reliability of a novel wireless system to analyse lumbar spine posture

Lumbar posture is commonly assessed in non-specific chronic low back pain (NSCLBP), although quantitative measures have mostly been limited to laboratory environments. The BodyGuard™ is a spinal position monitoring device that can monitor posture in real time, both inside and outside the laboratory. The reliability of this wireless device was examined in 18 healthy participants during usual sitting and forward bending, two tasks that are commonly provocative in NSCLBP. Reliability was determined using intraclass correlation coefficients (ICC), the standard error of measurement (SEM), the mean difference and the minimal detectable change (MDC90). Between-day ICC values ranged from 0.84 to 0.87, with small SEM (5%), mean difference (<9%) and MDC90 (<14%) values. Inter-rater ICC values ranged from 0.91 to 0.94, with small SEM (4%), mean difference (6%) and MDC90 (9%) values. Between-day and inter-rater reliability are essential requirements for clinical utility and were excellent in this study. Further studies into the validity of this device and its application in clinical trials in occupational settings are required. Statement of Relevance:A novel device that can analyse spinal posture exposure in occupational settings in a minimally invasive manner has been developed. This study established that the device has excellent between-day and inter-rater reliability in healthy pain-free subjects. Further studies in people with low back pain are planned.

Can we reduce the effort of maintaining a neutral sitting posture? A pilot study

Neutral sitting postures encouraging lumbar lordosis have been recommended in the management of sitting-related low back pain (LBP). However, prolonged lordotic sitting postures can be associated with increased fatigue and discomfort. This pilot study investigated whether changing the type of chair used in sitting can reduce the effort of maintaining a neutral sitting posture. The muscle activation of six trunk muscles was recorded using surface electromyography in 12 painfree participants. Participants were facilitated into a neutral sitting posture for 1 min on both a standard backless office chair and a dynamic, forward-inclined chair (Back App). Lumbar multifidus activity was significantly lower on the Back App chair (p=0.013). None of the other five trunk muscles measured demonstrated a significant difference in activity between the chairs. There was no significant difference (p=0.108) in the perceived effort of maintaining the neutral sitting posture on the two chairs. This study suggests that the lumbar multifidus activation required to maintain a neutral sitting posture can be reduced by considering the type of chair used. The mechanism through which the Back App chair reduces lumbar multifidus activation is unclear, but the greatest difference between chairs is the degree of hip flexion. The ability to maintain a neutral lumbar posture with less lumbar multifidus activation is potentially advantageous during prolonged sitting. Further investigations of the effects of chair design on longer duration sitting, and among LBP subjects, are warranted.

The effect of dynamic sitting on trunk muscle activation: A systematic review.

The purpose of this systematic review was to investigate the effect of dynamic sitting on trunk muscle activation in sitting. Electronic databases were searched by two independent reviewers. Studies were included if they compared the effect of dynamic sitting on trunk muscle activation to a more static sitting condition. Seven studies were eligible for inclusion, six of which were rated as high-quality using the PEDro scale. Five studies reported no difference in trunk muscle activation. Two studies reported a difference in trunk muscle activation, yet this was associated with increased discomfort, increased fatigue and greater spinal shrinkage. Furthermore, the changes reported in these two studies may be more related to the absence of a backrest rather than dynamic sitting. Therefore, the findings of this review suggest dynamic sitting does not significantly change trunk muscle activation. No randomised clinical trials or longitudinal design studies were found which evaluated the effect of dynamic sitting on trunk muscle activation, limiting the ability to make definitive conclusions about causality. The implications of the results, and recommendations for future research, are discussed.

Specific flexion-related low back pain and sitting: comparison of seated discomfort on two different chairs

No study has examined the effectiveness of prescribing seating modifications according to the individual clinical presentation of people with low back pain (LBP). A dynamic, forward-inclined chair (‘Back App’) can reduce seated paraspinal muscle activation among pain-free participants. This study examined 21 participants whose LBP was specifically aggravated by prolonged sitting and was eased by standing. Low back discomfort (LBD) and overall body discomfort (OBD) were assessed every 15 min while participants sat for 1 h on both the dynamic, forward-inclined chair and a standard office chair. LBD increased significantly more (p = 0.005) on the standard office chair, with no significant difference (p = 0.178) in OBD between the chairs. The results demonstrate that, in a specific flexion-related subgroup of people with LBP, increased LBD during sitting can be minimised through modifying chair design. Mechanisms that minimise seated discomfort may be of relevance in LBP management, as part of a biopsychosocial management plan. Practitioner summary: This study examined low back discomfort (LBD) during a typing task among people with low back pain (LBP). Sitting on a dynamic, forward-inclined chair resulted in less seated LBD than sitting on a standard office chair. Further research is required to examine the long-term effectiveness of ergonomics interventions in LBP.