Are there differences in cervical inter-vertebral laxity or translation motion between patients with neck pain and healthy controls?
Start date: 13 May 2015
Journal: Journal of Chiropractic Medicine
The Global Burden of Disease (2010) study suggests that the prevalence of neck pain-related disability is higher than previously estimated and that the burden it places on society and healthcare can be expected to rise with an ageing world population (Murray et al. 2012). However, despite the technological advances in medicine over the 20th and early 21st centuries, neck pain remains something of an enigma regarding accurate diagnosis with no tests demonstrating clear validity (Nordin et al. 2008). Most neck pain is considered to be mechanical in nature (Binder 2008) but no treatments directed at mechanical neck pain show clear superiority or large effect sizes (Hurwitz et al. 2008). More accurate diagnosis is needed to better target treatment if the burden of neck pain-related disability is to be appropriately managed.
Quantitative fluoroscopy (QF) is a relatively new technology that has high accuracy and repeatability in the cervical spine for sagittal plane inter-vertebral angular range (Branney and Breen 2014) but has not been assessed for the measurement of inter-vertebral translation and laxity, both of which, in excess, are regarded as indicators of spinal instability (Anderson et al. 2012). Therefore, this study sought to determine the repeatability of QF in the measurement of cervical inter-vertebral translation and laxity and to determine if these feature more in patients with neck pain than healthy controls.
Twenty-nine patients with subacute or chronic neck pain (21 female) and 30 age and gender-matched healthy controls were imaged during flexion and extension using a standardised QF acquisition protocol. Between-group differences in inter-vertebral translation and laxity (C1/2 to C5/6) were determined using unpaired t-tests. In a subgroup of 10 healthy volunteers fluoroscopic sequences were analysed twice six weeks apart by one observer and once by a second observer. Intra- and inter-observer agreement and reliability were determined using the standard error of measurement (SEM) and intra-class correlation coefficient (ICC).
The largest intra-observer SEM for translation at any level was 0.45mm (0.59mm for inter-observer). ICCs varied by segmental level and ranged from poor [0.012 (95% CI: -0.749 to 0.760)] to excellent [0.96 (95% CI: 0.829 to 0.991)]. In patients with neck pain translation was significantly reduced compared to healthy controls at C1/2 (mean difference -1.1mm, 95% CI: -1.90 to -0.36, p = 0.005) and C4/5 in extension (mean difference -0.6mm, 95% CI: -0.98 to -0.021, p = 0.003). For laxity, the largest SEM at any level was 0.036 and the lowest ICC 0.68 (95% CI: 0.085 to 0.918). The only significant difference in laxity was for C1/2 in flexion which was less lax in the patient group (mean difference -0.068, 95% CI: 0.0066 to 0.1300, p = 0.03). Conclusion
QF exhibited good agreement but variable reliability for translation and good overall repeatability for laxity. Neither excessive translation nor laxity was evident in this group of patients with mild-moderate non-traumatic neck pain.