Lumbar Kinematics , Functional Disability and Fear Avoidance Beliefs Among Adults with Nonspecific Chronic Low Back Pain

OBJECTIVES
This study aimed to examine correlations between lumbar kinematics, functional disability and fear avoidance beliefs among adults with nonspecific chronic low back pain (LBP).


METHODS
This cross-sectional study was conducted between March and December 2014. A total of 32 adults diagnosed with nonspecific chronic LBP were recruited from outpatients attending either an orthopaedic clinic at a university hospital or a private physiotherapy clinic in Malaysia. Lumbar kinematics were measured using sensors attached at the first lumbar (L1) and second sacral (S2) vertebrae levels. The Oswestry Disability Index (ODI) and Fear-Avoidance Beliefs Questionnaire (FABQ) were used to assess degree of functional disability and fear avoidance beliefs, respectively.


RESULTS
For maximum range of motion, positive correlations were observed between ODI scores and right lateral flexion and right rotation (P = 0.01 each), although there was a negative correlation with left rotation (P = 0.03). With maximum angular velocity, ODI scores were positively correlated with right and left lateral flexion L1 (P = 0.01 and <0.01, respectively) but negatively correlated with left lateral flexion L2 (P = 0.04). Regarding minimum angular velocity, ODI scores were positively correlated with left lateral flexion S2 (P <0.01) but negatively correlated with right and left lateral flexion L1 (P = 0.02 each), right rotation L1 (P = 0.02) and left rotation S2 (P = 0.01). No significant correlations were found between lumbar kinematics and FABQ scores.


CONCLUSION
These findings suggest that certain lumbar kinematic parameters are correlated with functional disability, but not with fear avoidance beliefs.


L
ow back pain (lbp) is the term used to indicate lumbosacral pain originating between the bottom of the twelfth rib and above the gluteal fold. 1 It is a global health problem with a lifetime prevalence of over 80%; moreover, 11-12% of adults with LBP suffer from physical disabilities. 1,2Acute LBP is defined as pain that occurs suddenly after a minimum of six months without pain and lasting for six weeks or less, whereas chronic LBP denotes periodic pain persisting for more than three months with increased risk of recurrence. 1,2The prevalence of chronic LBP is approximately 23%. 2 In general, acute LBP has an organic pathology; however, biopsychosocial factors that can predispose an individual to chronic LBP are often present at the time of onset. 3umbar kinematic measurements include an assessment of the range of motion (ROM), movement velocity and acceleration of the lumbar spine. 4These variables may assist in the identification of adults at risk of LBP as adults with chronic LBP have shown variations in lumbar biomechanical parameters, including reduced ROM, velocity and acceleration. 5,6owever, the current focus on structural and biomechanical abnormalities is inadequate to explain chronic LBP and its associated disabilities, with previous research supporting the inclusion of biopsychosocial factors. 7,80][11][12] However, it is unclear whether adults with LBP who have pain-related fear of movement deliberately avoid movements of increased velocity and acceleration.
Pain-related fear of movement can be measured using the Fear-Avoidance Beliefs Questionnaire (FABQ), which quantifies an individual's fear of pain as a result of alterations in behaviour to avoid pain. 8 positive correlation has been reported between FABQ scores and disability measures; however, inconsistent results have been found regarding the relationship between pain-related fear and decreased activity.12,13 The Oswestry Disability Index (ODI) has been deemed suitable for determining an individual's disability in relation to chronic pain, with higher scores indicating greater levels of disability.14,15 Nevertheless, findings of correlations between lumbar ROM measurements and functional impairment in adults with chronic LBP have not been consistent.16 Although a weak relationship between flexion ROM and disability in adults with LBP has been found, ROM and the angular velocity of flexion and extension movements have shown an inconsistent relationship with ODI scores.4,17 Overall, there are limited and conflicting data regarding the correlations between lumbar kinematics and functional disability and fear avoidance.Further studies on this topic may assist clinicians in the management and care of adults with chronic LBP.The current study therefore aimed to examine the correlation between lumbar kinematics, functional disability and fear avoidance beliefs among adults with chronic LBP.

Methods
This cross-sectional study was conducted between March and December 2014.A total of 32 adults with chronic LBP persisting for more than three months were recruited from a list of outpatients at either an orthopaedic clinic at the Pusat Perubatan Universiti Kebangsaan Malaysia Hospital, Kuala Lumpur, Malaysia, or a private physiotherapy clinic in Petaling Jaya, Malaysia.The inclusion criteria included outpatients between 20-45 years old with pain originating between the lower ribs and inferior gluteal fold who had been diagnosed by a doctor as having chronic LBP.Patients were excluded from the study if they were currently taking any medications or if they had referred or radicular pain, overt neurological signs (i.e.sensory deficits or motor paralysis), psychological illnesses or "red-flag" disorders (e.g.neoplasms, inflammatory disease, fractures or infections).Women who were pregnant were also excluded.A power analysis for a bivariate normal model was performed using G*Power software, Version 3.1.9.2 (Heinrich Heine University, Dusseldorf, Germany); this indicated that the sample size was sufficient for the purposes of the study (effect size = 0.50; power = 0.80; P <0.05). 18vances in Knowledge -The current study identified significant correlations between several lumbar kinematic parameters and functional disability as determined using the Oswestry Disability Index among adults with nonspecific chronic low back pain (LBP).However, no correlations were observed between lumbar kinematic parameters and fear avoidance beliefs.Lumbar kinematic parameters, including lumbar ROM, velocity and acceleration, were measured using an inertial measurement system (MTx human motion tracker, Xsens Technologies B.V., Enschede, Netherlands).This system provides an accurate and drift-free 360 ° view with a three-dimensional spinal range of movement and coupled motion measurements.The first lumbar (L1) and second sacral (S2) spinous processes were identified by palpating the spine when the participant was in a standing position.Two sensors set at 50 Hz were attached perpendicularly to each other and the spinous processes of the L1 and S2 vertebrae and secured to the trunk with an elastic strap.Participants were then requested to move to their full ROM, while limiting pelvic movements as much as possible.The ROM of six physiological movements was then obtained by calculating the relative angles between the two sensors using a direction cosine matrix that transforms vectors in the body frame to reference frame analysis (MATLAB software, MathWorks Inc., Natick, Massachusetts, USA).Each participant was requested to perform three repetitions of flexion, extension, lateral flexion (left and right) and rotation (left and right) with their feet shoulder-width apart and knees extended.The averages of the three measurements were taken as ROM and velocity results.Participants were given a demonstration of this process before official recording of the data began.

Application to
The sociodemographic characteristics of the participants were obtained, including age, gender and employment status.Weight and height were measured to calculate body mass index (BMI).Back pain was evaluated using a visual analogue scale (VAS), which has a 10 cm horizontal line numbered from 0 to 10 with 0 signifying no pain, 5 signifying moderate pain and 10 signifying the worst possible pain. 19Participants were required to mark the point on the scale that they felt represented their current pain status.The 10-item ODI questionnaire was used to quantify the severity of disability for each participant, with a score between 0-5 being assigned for each of the following items: pain intensity, personal care, lifting, walking, sitting, standing, sleeping, sex life, social life and travelling. 14he total score of the 10-item ODI questionnaire was recorded as a percentage.Fear avoidance beliefs were assessed using the 5-item physical activity (FABQ-PA) and 11-item work (FABQ-W) subscales of the FABQ, with scores ranging on a Likert scale of 0-6. 8 score of 6 was taken to denote the highest level of fear avoidance belief. 8Both the ODI and FABQ questionnaires were completed by the researchers in English during interviews with the participants.
All data analysis was performed using the Statistical Package for the Social Sciences (SPSS), Version 20 (IBM Corp., Chicago, Illinois, USA).A Shapiro-Wilk test indicated that most of the kinematic variables were not normally distributed; thus, Spearman's rank correlation coefficient was used to determine correlations between the variables.A P value of <0.05 was considered to be statistically significant.
Ethical approval for this study was obtained from the Secretariat for Research & Ethics of the Universiti Kebangsaan Malaysia, Kuala Lumpur (UKM #1.5.3.5/244/NN-147-2013).All participants were provided with written and verbal information about the study procedures and gave informed verbal consent for participation.

Results
The sociodemographic characteristics and mean ODI and FABQ scores of the participants are shown in Table 1.The mean lumbar ROM for flexion and extension was 37.52 ± 9.25 degrees and 9.33 ± 7.61 degrees, respectively.Mean rotation and lateral flexion were between 11.67-13.72degrees and 8.23-11.05degrees, respectively [Table 2].Table 3 depicts the mean minimum and maximum angular velocity measurements.
There were significant moderate positive correlations between ODI scores and the right lateral flexion and right rotation (P = 0.01 each) variables of maximum ROM, the right and left lateral flexion L1 (P = 0.01 and <0.01, respectively) variables of maximum angular velocity and the left lateral flexion S2 (P <0.01) variable of minimum angular velocity.Significant weak-to-moderate negative correlations were observed between ODI scores and the left rotation (P = 0.03) variable of maximum ROM, the left lateral flexion S2 (P = 0.04) variable of maximum angular velocity and the right and left lateral flexion L1 (P = 0.02 each), right rotation L1 (P = 0.02) and left rotation S2 (P = 0.01) variables of minimum angular velocity.There were no significant correlations between lumbar kinematics and either FABQ-PA or FABQ-W scores [Table 4].

Discussion
This study aimed to examine potential correlations between lumbar kinematics, functional disability and fear avoidance beliefs among adults with chronic LBP.However, only functional disability was found to be significantly correlated with certain lumbar kinematic parameters, suggesting that greater perceived functional disability was correlated to a decrease or increase in certain aspects of lumbar ROM and angular velocity.Using an electrogoniometer and torsiometer, Bible et al. previously reported mean full active ROM measurements for flexion (54.6 degrees), extension (26.6 degrees), left and right lateral bending (17.5-19.5 degrees) and left and right axial rotation (16.7-17.6 degrees) for adults without LBP. 20In comparison, participants in the current study had lower lumbar ROM measurements, with approximately 30% reduced flexion and rotation, 65% reduced extension and 35% reduced rotation.These differences in findings may be due to variations in measurement instruments and study protocols.However, it is noteworthy that extension ROM was the most limited movement in the current study, followed by rotation and side flexion.
In the current study, mean maximum right lateral flexion and right rotation variables of ROM had a positive correlation with ODI scores, whereas there was a negative correlation between left rotation and ODI scores.These results demonstrate an inconsistent correlation between lumbar movements and disability.Clinically, these results are acceptable as both declined and increased mobility may be related to functional ability. 21In a previous study, Parks et al. concluded that the association between lumbar motions and functional ability was either weak or absent. 22oreover, a negative correlation between ODI and left rotation ROM has also been described in an earlier report. 23Movement impairment among adults with chronic LBP may be due to an associated cocontraction of the lumbar-pelvic muscles and muscle spasms which can lead to limited motion and injury. 24n the other hand, hypermobility may also exist in certain spinal segments, causing spinal instability and impaired neuromuscular control, eventually affecting an individual's ability to function normally. 25As with ROM, inconsistent results were also observed in the current study with regards to lumbar velocity.The authors of the current study speculate that this may be due to the complex relationship of lumbar kinematics with functional impairment.Other factors may have influenced the results, such as limb dominance, laterality of pain, level of pain and disability.Adults with LBP have been found to move more slowly compared to healthy individuals. 26t is also noteworthy that the mean ODI score of participants in the current study indicated minimal disability (19.2%), while the mean VAS score (2/10) suggested only mild-to-moderate disability. 14Thus, the results of the present study could have been influenced by the lack of severity of LBP symptoms among the participants.In addition, asymmetries in lumbar motion have been noted among adults without LBP which were unrelated to any limitations and were believed to be derived from daily habitual movements. 27ain-related fear is believed to be an important factor in determining disability in chronic LBP, rather than pain or physical impairment alone. 22The present study found that lumbar kinematic variables were not associated with FABQ-PA or FABQ-W scores.Similarly, Demoulin et al. reported that painrelated fear measures were not significantly related to the physical capacity of the spine. 28However, these findings are contradictory to those of earlier studies reporting associations between physical ability and  9,11,29 In one study, Geisser et al. observed a significant correlation between pain-related fear and decreased lumbar flexion among participants with chronic LBP. 9 Vaisy et al. reported that ROM and angular velocity were associated with psychological characteristics, including fear of movement. 11rotle et al. found that fear avoidance beliefs were significantly related to disability after controlling for sociodemographic, pain-related and clinical variables and excluding distress variables. 30Another study found that a combination of psychological factors, including fear avoidance beliefs, anxiety and pain catastrophising, determined functional disability in adults with chronic LBP. 31 Nevertheless, other sociodemographic and psychosocial factors such as income, education level, type of management received, selfefficacy and motivation may need to be accounted for when considering a relationship between pain-related fear of movement and functional ability.
The findings of the present study add to existing controversy in the literature regarding the correlation between lumbar motion, functional ability and fear avoidance beliefs.Differences in findings may be due to inter-study variations in measurement instruments, protocols, participant selection and analysis systems.Despite this, the results of the current study may be of interest to clinicians in the assessment and management of adults with nonspecific chronic LBP.It is important to note that observation of lumbar ROM through visual estimations may not show small differences.However, measurements of higher order kinematics, such as movement velocity and acceleration, may not be feasible in clinical settings as they often require costly instrumentation.Physiotherapists should provide individually tailored exercises focusing on lumbar rotation and lateral flexion movements as well as lumbar extension when treating adults with nonspecific chronic LBP.
There are a few limitations to this study.Firstly, the sample size was limited and confined to adults with nonspecific chronic LBP.Secondly, data regarding quality of movement, specific locations of pain and range of pain were not analysed.Therefore, the results of this study cannot be generalised to other types of LBP with symptoms that include unilateral pain, hypomobility or hypermobility.Further studies are required assessing lumbar kinematics among patients with different types of LBP in comparison to a control group. 32There is also a need for future research to examine the relationship between lumbar kinematics and sustained prolonged functional activities among adults with nonspecific chronic LBP.

Conclusion
The results of this study suggest that certain components of rotation and lateral flexion are correlates of functional disability, but not fear avoidance beliefs.Lumbar rotation and lateral flexion movements should therefore be emphasised in addition to lumbar extension during rehabilitation therapy for adults with nonspecific chronic LBP.In addition, both lumbar kinematics and functional impairment should be taken into consideration in the assessment and management of adults with nonspecific chronic LBP.

Table 2 :
Mean maximum range of motion variables among adults with chronic low back pain (N = 32)

Table 1 :
Demographic characteristics, degree of functional disability* and fear avoidance belief † scores among adults with chronic low back pain (N = 32) 84 = standard deviation; VAS = visual analogue scale; BMI = body mass index; ODI = Oswestry Disability Index; FABQ-PA = physical activity subscale of the Fear-Avoidance Beliefs Questionnaire; FABQ-W = work subscale of the Fear-Avoidance Beliefs Questionnaire.*Functional disability was assessed using the Oswestry Disability Index.14†Fearavoidancebeliefs were assessed using the Fear-Avoidance Beliefs Questionnaire.8NancyG.Jette, Yi L. Lim, Hui L. Lim, Sabarul A. Mokhtar, Kok B. Gan and Devinder K. A. SinghClinical and Basic Research | e433

Table 3 :
Mean minimum and maximum angular velocity variables among adults with chronic low back pain (N = 32)Lumbar Kinematics, Functional Disability and Fear Avoidance Beliefs Among Adults with Nonspecific Chronic Low Back Pain e434 | SQU Medical Journal, November 2016, Volume 16, Issue 4

Table 4 :
Correlations between lumbar kinematic variables and functional disability* and fear avoidance beliefs † among adults with chronic low back pain (N = 32) Nancy G. Jette, Yi L. Lim, Hui L. Lim, Sabarul A. Mokhtar, Kok B. Gan and Devinder K. A. Singh Clinical and Basic Research | e435 fear avoidance beliefs.