Contents lists available at ScienceDirect Clinical Biomechanics journal homepage: www.elsevier.com/locate/clinbiomech Assessment of cervical stiffness in axial rotation among chronic neck pain patients: A trial in the framework of a non-manipulative osteopathic management P.-M. Dugailly a, ⁎ , A. Coucke a , W. Salem b , V. Feipel a a Laboratory of Functional Anatomy, Faculty of Motor Sciences, Université Libre de Bruxelles (ULB), Brussels, Belgium b Research Unit in Osteopathy, Faculty of Motor Sciences, Université Libre de Bruxelles (ULB), Brussels, Belgium ARTICLE INFO Keywords: Cervical spine Axial rotation Stiffness Neck pain Osteopathic treatment Cervical motion ABSTRACT Background: Cervical stiffness is a clinical feature commonly appraised during the functional examination of cervical spine. Measurements of cervical stiffness in axial rotation have not been reported for patients with neck pain. The purpose of this study was to investigate cervical spine stiffness in axial rotation among neck pain patients and asymptomatic subjects, and to analyze the impact of osteopathic management. Methods: Thirty-five individuals (17 patients) were enrolled. Measurements were carried out for left-right axial rotation using a torque meter device, prior and after intervention. Passive range of motion, stiffness, and elastic- and neutral zone magnitudes were analyzed. Pain intensity was also collected for patients. The intervention consisted in one single session of non-manipulative osteopathic treatment performed in both groups. Findings: A significant main effect of intervention was found for total range of motion and neutral zone. Also, treatment by group interaction was demonstrated for neutral-, elastic zone, stiffness in right axial rotation, and for total neutral zone. Significant changes were observed in the clinical group after intervention, indicating elastic zone decrease and neutral zone increase. In contrast, no significant alteration was detected for the control group. Interpretations: Stiffness characteristics of the cervical spine in axial rotation are prone to be altered in patients with neck pain, but seem to be relieved after a session of non-manipulative manual therapeutic techniques. Further investigations, including randomized clinical trials with various clinical populations and therapeutic modalities, are needed to confirm these preliminary findings. 1. Introduction Neck pain is a frequent clinical musculoskeletal symptom with a prevalence ranged from 17% to 75% (Fejer et al., 2006) and an annual prevalence ranged from 30% to 50% (Hogg-Johnson et al., 2008). This condition represents one of the most common causes of disability in Western Europe, entailing important expenditures for the health care system (Hoy et al., 2014; Martin et al., 2008; Murray et al., 2012). Besides, spinal stiffness in terms of flexibility impairment is a highly contributing factor related to musculoskeletal disability (Daniels et al., 2015; Ingram et al., 2015; Stanton et al., 2017). Therapeutic options such as physical and manual approaches (i.e. manipulation, mobilization, exercises) are commonly recommended for treating neck pain with relevant clinical outcomes. Prior to using these modalities, physical examination involves assessment of pain pattern, active range of motion, and motion palpation. The latter represents a manual method for judging cervical stiffness alteration usually char- acterized as an increase of resistance to movement of a specific ver- tebral segment including the surrounding soft tissues (Manning et al., 2012). Clinical validity of this application has been demonstrated (Fernandez-de-las-Penas et al., 2005; Humphreys et al., 2004; Rey-Eiriz et al., 2010). Nevertheless clinical prognosis related to these parameters is still questioned. Innovative methods have been developed for assessing several biomechanical features of the spine in vivo. These techniques aim to quantify the stiffness characteristics (i.e. neutral zone, stiffness coeffi- cient, flexibility) for the lumbar spine (Wong and Kawchuk, 2017) and for the cervical spine (McClure et al., 1998; McGill et al., 1994; Snodgrass et al., 2008). From these investigations, several authors de- monstrated measurement feasibility and validity (Snodgrass et al., 2008), influence of spinal positioning (Edmondston et al., 1998; Snodgrass and Rhodes, 2012), and clinical relevance for specific https://doi.org/10.1016/j.clinbiomech.2018.02.005 Received 26 January 2017; Accepted 6 February 2018 ⁎ Corresponding author at: Laboratory of Functional Anatomy, Faculty of Motor Sciences, Université Libre de Bruxelles (ULB), 808 route de Lennik, 1070 Bruxelles, Belgium. E-mail address: pdugaill@ulb.ac.be (P.-M. Dugailly). Clinical Biomechanics 53 (2018) 65–71 0268-0033/ © 2018 Elsevier Ltd. All rights reserved. T