Relationships between sagittal postures of thoracic and cervical spine, presence of neck pain, neck pain severity and disability

Abstract

This was a cross-sectional correlation study to explore the relationships between sagittal postures of thoracic and cervical spine, presence of neck pain, neck pain severity and disability. Moreover, the reliability of the photographic measurement of the sagittal posture of thoracic and cervical spine was investigated. Forty-five subjects without neck pain and forty-seven subjects with neck pain were recruited. Using a photographic method, the sagittal thoracic and cervical postures were measured by the upper thoracic and the craniovertebral (CV) angles respectively. The Numeric Pain Rating Scale (NPRS) and Chinese version Northwick Park Neck Pain Questionnaire (NPQ) were used to assess neck pain severity and disability. The upper thoracic angle was positively correlated (r_s = 0.63, p < 0.01) while the CV angle was negatively correlated (r_s = −0.56, p < 0.01) with the presence of neck pain. The upper thoracic angle was negatively correlated with the CV angles (r_s = −0.62, p < 0.01) in subjects with neck pain. Similar to the CV angle, the upper thoracic angle was moderately correlated with the neck pain severity (r_s = 0.43, p = 0.01) and disability (r_s = 0.44, p = 0.02). The upper thoracic angle (OR = 1.37, p < 0.01) was a good predictor for presence of neck pain even better than that of the CV angle (OR = 0.86, p = 0.04).

Introduction

In European and North American populations, approximately 33–54% of adults experience neck pain during their lives (Bovim et al., 1994, Côte et al., 1998, Côte et al., 2000). The causes of neck pain are not completely understood but are proposed to be related to various anatomical structures like facet joints, uncovertebral joints and intervertebral discs (Bogduk and Aprill, 1993, Harrison et al., 1996). Norlander et al., 1996, Norlander et al., 1997 and Norlander and Nordgren (1998) suggested that poor mobility in the upper thoracic spine was a predictor for neck and shoulder pain. McAviney et al. (2005) compared the cervical X-ray films of normal subjects and subjects with neck pain retrospectively. They measured the absolute rotation angle of cervical lordosis and found that a cervical lordosis of 20° or less was a risk factor to develop cervicogenic symptoms. Yip et al. (2008) reported that a smaller craniovertebral (CV) angle was correlated with neck pain severity and disability. Silva et al. (2009) also found that a smaller CV angle and the presence of neck pain were related. The altered sagittal curvature of cervical spine was proposed to change the stresses and strains on different anatomical structures which became more vulnerable in suffering wear and tear (Harrison et al., 1996, Bryden and Fitzgerald, 2001, Bonney and Corlett, 2002). Biomechanically the cervical, thoracic and the lumbar spine are interrelated. Any changes of the cervical lordosis may be due to postural changes of the thoracic and lumbar spine. However, no study has been conducted to explore the relationship between neck pain and the sagittal posture of thoracic spine.

Norlander et al., 1996, Norlander et al., 1997 and Norlander and Nordgren (1998); Cleland et al. (2007), and Gonzalez-Ielesias et al. (2009) believed that the posture of thoracic spine was related to neck pain because thoracic manipulation could restore the mobility in cervicothoracic region. Nevertheless, they did not measure the segmental mobility before and after thoracic manipulation for validating their hypotheses.

Meanwhile, there was a lack of gold standard in measuring the sagittal postures of both thoracic and cervical spine (Ettinger et al., 1994, Lunden et al., 1998, Mannion et al., 2004, Harrison et al., 2005a, Harrison et al., 2005b). Although Falla et al. (2007) introduced a convenient photographic measurement of sagittal postures of thoracic and cervical spine, the intraclass correlation coefficient (ICC (2,2) were all greater that 0.9) was adopted from other studies measuring the angular movement of knee (Russell et al., 2002, 2003).

Currently the literature does not give concrete information on the relationship between neck pain and sagittal posture of the spine. Moreover, the reliability of the photographic measurement of the sagittal posture of thoracic and cervical spine is still questionable.

Thus, the objectives of this study were to determine:

• 1.the intra and inter-rater reliability of a photographic measurement of the sagittal postures of thoracic and cervical spine;

• 2.if there is any difference in the sagittal posture of the thoracic and cervical spine between asymptomatic subjects and individuals with neck pain;

• 3.if there is any difference in the sagittal posture of the thoracic and cervical spine between asymptomatic subjects and individuals with neck pain;

• 4.if there is any relationship between neck pain and posture of the thoracic and cervical spine in the sagittal plane;

• if sagittal postures of thoracic and cervical spine are good predictors for neck pain prevalence, neck pain severity and disability;

The significance of this study may give researchers further objective information to evaluate the relationship between neck pain and thoracic and cervical posture. Moreover, results may help to improve the management of patients with neck pain.