Women with late whiplash syndrome have greatly reduced load-bearing of the cervical spine. In-vivo biomechanical, cross-sectional, lateral radiographic study.

Abstract

No study has been conducted to ascertain whether the load-bearing capacity of the cervical spine is reduced in vivo in late whiplash syndrome (LWS). To compare the segmental cervical angular values across C0-C6, between two conditions: without versus with external axial load upon the head in three groups of women. A single-blind, age-Body Mass Index (BMI) matched, radiographic, cross-sectional study. Radiographic Department at a University Hospital. One hundred eighty-two women, aged between 18-50 years were enrolled. Participants were divided into 3 groups: a group with LWS (N.=62) and two control groups: a chronic insidious neck pain (IONP) group (N.=60) and an asymptomatic group (N.=60). Prior to and on the same day as the radiographic examination took place, BMI in kg/m2 was recorded and all participants answered the Neck Disability Index (NDI). The two symptomatic groups answered also three other pain and disability questionnaires. Analysis of variance (mixed-model ANOVA) for repeated measures was used for comparison. Significant differences between groups, and the two conditions tested was revealed, but only within the asymptomatic and the IONP groups (P<0.0001), but not within the LWS group (P=0.9433). Unexpectedly the women with LWS adopted a rigid horizontal translation strategy when external load was applied upon their head. The inter-rater and intra-rater segmental measurements were highly reliable. Women with LWS scored significantly higher on all questionnaires. The results of this study strongly indicate that the load-bearing capacity of the cervical spine is reduced in vivo in women with LWS. The study shows, for the first time, that the cervical spine in women with LWS predominately functions such as a rigid cylinder when loaded. The study implies that the cervical column is extremely weak in the LWS and that the superficial neck muscles, which are designed to move the head-neck, must compensate and act as rigid stabilizers. This causes great joint reaction forces through the cervical spine and its injured inert structures maintaining the pain and disability, as the results of the questionnaires show.