The Standardised Mensendieck Test as a tool for evaluation of movement quality in patients with nonspecific chronic low back pain

1. Introduction

Low back pain (LBP) is a highly prevalent [1] global health problem causing more years lived with disability than any other health condition [2]. The causes of LBP are multifactorial and associated with a complex interplay of biopsychosocial factors [3]. In about 85–90% of all LBP cases, the pathoanatomical aetiology is unknown and is defined as nonspecific [4]. Physical features such as maladaptive postures and movement patterns [5], [6], [7] and cognitive factors, like fear of movement and (re)injury [8] are merely some aspects associated with chronicity [9].

Treatment of nonspecific chronic LBP (NSCLBP) is challenging and no single method is shown to be superior to others. Recent update of clinical guidelines for LBP and sciatica recommends a combination of a physical and psychological programme, incorporating a cognitive behavioural approach for treatment of NSCLBP following a thorough patient examination [10]. Accurate assessment is recommended for targeted treatment of NSCLBP, however evaluation of psychosocial factors, pain, quality of movement and posture can be a challenging task, particularly in a daily clinical setting when time is limited and advanced equipment is rarely available. Consequently, in recent years, the development of assessment instruments that may help the clinicians to make informed decisions about back pain treatment and yet are easy to implement in daily practise has been strongly emphasised. One such instrument is a STarT Back tool [11], a short prognostic questionnaire, which can help to stratify patients into different types of treatments. Nevertheless, self-report questionnaires have limited value in evaluation of bodily characteristics and quality of movement, which constitutes a core of physiotherapists’ focus when treating back pain. Maladaptive movement patterns (e.g. cautious tensed movements) [12] and maladaptive respiration patterns (e.g. shallow thoracic breathing, withholding breath during movements) are commonly observed [13], [14]. These maladaptive patterns can also potentially be targeted during treatment of NSCLBP, both through specific exercises and cognitive behavioural approaches [12]. Currently, there is no agreement, amongst health professionals, on how movement quality should be standardised in patients with non-specific LBP [15]. We are thus in need for instruments that can provide us with a standardised evaluation of movement quality and breathing pattern, that are easy to perform and implement in clinical practise [7], [15].

The Standardised Mensendieck Test (SMT) has previously been reliability tested and validated in women with chronic pelvic pain (CPP) [16], but not in NSCLBP-patients. In the present study, the aim was to apply the SMT to evaluate bodily characteristics and quality of movement in NSCLBP patients. Additionally, since fear avoidance beliefs play an important role in NSCLBP and has previously been shown to moderate changes in spinal movement control [17], we also wanted to investigate the associations between the SMT and the TAMPA scale of kinesiophobia (TSK) and pain measured by the numeric rating scale (NRS).

2. Methods

Twenty patients with NSCLBP and 20 healthy controls were included in the study. The patients were recruited from the Department of Pain Management and Research, Oslo University Hospital, a third line service receiving referrals nationwide from both primary and secondary care. The healthy controls (15 women and five men) were students and employees recruited from Oslo and Akershus University College. Patients eligible for the study were identified after assessment including extensive psychometric evaluation and examination by a physician specialised in assessment of pain patients. Patients, age 18–55 years, who had NSCLBP for at least 6 months, were eligible for inclusion in this study. Good Norwegian verbal and written skills were a further requirement. All eligible patients were contacted by a physiotherapist and were invited to participate in the study. The exclusion criteria are described in Table 1.

3. Results

4. Discussion

To our best knowledge, this is the first study investigating quality of movement and respiration pattern with the SMT in NSCLBP patients. The main findings showed that patients with NSCLBP had significantly poorer scores than controls on every item in all domains of the SMT. The differences were most pronounced in the movement pattern domain (mean difference 2.4). This represents in clinical and practical terms a clear and easily observed difference in movement quality. The two items of movement pattern domain with the largest difference between the groups were the horizontal and vertical arm lift (mean difference of 3.25 and 3.38, respectively). In these two tests, participants are asked to lift their arms into a horizontal and a vertical position, respectively and then let them “go” in a relaxed manner. The ability to let the arms “go” is scored. The large difference between the groups indicates that NSCLBP patients had significant problems with releasing muscle tension, displaying a tensed movement pattern. A possible explanation of this finding might be reduced body awareness and a reduced ability to recognise the level of tension in the muscles during the performance of functional movements among the patients. Such patterns have been previously registered in other groups of chronic pain patients as chronic pelvic and vulvar pain [21], [22]. Movement aberrations and hampered respiration have also been observed in musculoskeletal pain conditions and psychiatric disorders [23] and CPP [16]. From a patient perspective, the meaning of having body awareness can be expressed as being embodied; being in contact with and living in one’s body, furthermore living in relation to others and in society [24]. Quality of movement is represented by an interactive process between biomechanical, physiological, psycho-socio-cultural and existential themes [25]. Similarly, Sundén et al. [26] state that movements and the quality of movements signify cognitive, emotional, intentional and sociocultural features of the individual. Another possibility is that NSCLBP patients might have been afraid that letting their arms “go” will provoke their back pain. However, the fact that the items of movement pattern domain did not significantly correlate with the TSK scores suggested that the general level of kinesiophobia had no influence on the movement scores. The reduced ability to relax and coordinate the arms and legs may have been a somewhat unexpected finding amongst LBP patients.

The differences between the groups on other items of the movement pattern domain were clearly smaller, ranging from 1.33 (one leg raise) to 2.00/2.03 (parallel/diagonal arm swing). In practical terms, differences of less than two points might be difficult to discern reliably and its clinical significance is uncertain. In this respect, the one leg raise test-item seems to be of less value when evaluating quality of movement in NSCLBP patients. The between groups differences on all other domains of the SMT, including the respiration pattern, were approximately 1.6 points. Although significant, in practical terms the difference of 1.6 is relatively minor and might be difficult to observe reliably. This puts in question the ability of the SMT to assess the quality of the respiration pattern in NSCLBP. Interestingly, following further statistical analysis, where only females were compared to each other, the difference in the respiration pattern domain increased to 2.22, similar to that of the movement pattern domain. No major changes in mean scores on any other domains of the SMT were seen after removing males from the statistical analysis. This suggests that the respiration pattern in females suffering from NSCLBP is clearly less functional than in healthy controls. We found the diaphragmatic and low costal movements were decreased and replaced by an exaggerated upper costae contraction. These results are in line with several studies [16], [27], [28], investigating women with chronic pelvic pain and musculoskeletal pain, respectively. Overall little is known about the breathing pattern in CLBP patients. According to Jafari et al. [29], the influence of long-term pain on respiration continues to be unclear thus warrants attention in future studies. In one case-control study, a significantly more altered breathing pattern was found in NSCLBP patients observed during motor control tests compared to healthy controls [30]. The sample was small (n=10), and considering the 13-year pain history, the VAS score was contrastingly low (mean=24.4 mm), hence the results should be interpreted with some caution. According to Chaitow et al. [31], tense accessory respiratory muscles together with loss of thoracic cage compliance, can hamper normal chest movement, and exacerbate poor diaphragmatic descent. Furthermore, causes of breathing dysfunction can also have a psychosocial aetiology such as anxiety and depression [31], which is also highly comorbid with chronic pain [32].

5. Limitations

The main limitation of this study was the relatively low number of participants, particularly males. A larger sample would make it possible to perform analysis on subgroups of participants, i.e. divided by sex. The generalizability of the data to the general population may be limited as the patients were recruited from specialists care.

6. Conclusions

A marked difference in the SMT scores was observed between the NSCLBP patients and controls particularly with regard to movement pattern. In this respect, the SMT domains of movement might potentially be a valuable examination tool in assessment and treatment of NSCLBP patients.