Peterson G1,2, Nilsson D3, Trygg J3, Peolsson A2
1Uppsala University, Centre for Clinical Research Sörmland, Eskilstuna, Sweden, 2Linkoping University, Medical and Health Sciences, Linkoping, Sweden, 3Umea University, Computational Life Science Cluster (CLiC), Department of Chemistry, Umea, Sweden
Background: Persistent pain and disability is common in whiplash-associated disorders (WAD), resulting in substantial costs to both the individual and society.The cervical spine is heavily dependent on muscular support and previous studies have shown altered neck muscle function in individuals with chronic WAD. However, we lack diagnostic tools to measure neck muscle impairment and evaluate exercise interventions.
Purpose: To compare the interaction between three ventral neck muscles (sternocleidomastoid (SCM), longus capitis (Lcap) and longus colli (Lco)) after 3 months of NSE versus remaining on a waiting list (WL) without exercise. The purpose was also to determine whether 3 months of NSE improved ventral neck muscle function compared to a model for healthy individuals developed in an earlier study and to investigate the relationship between ventral neck muscle interactions, neck pain, self-reported neck disability, and neck muscle endurance.
Methods: This randomized control study included 26 individuals (NSE: n=13, 10 women and 3 men; median age 41 years, IQR 30-48 and WL: n=13, 11 women and 2 men; median age 40, IQR;27-47) with chronic WAD grade II-III. SCM, Lcap and Lco were recorded by ultrasound during 10 repetitive arm elevations, which often causes increased neck pain in WAD. The first and tenth arm elevations were analyzed with speckle tracking analyses. Ultrasound, pain, self-reported neck disability, and neck muscle endurance were recorded at baseline and after 3 months. The NSE group performed neck-specific exercises twice weekly for 3 months while the WL group remained on a waiting list for 3 months. Differences between muscles and groups were analysed with multivariate statistics.
Results: Significant between-group differences were found for neck muscle interactions at the 3-month follow-up (p 0.03). The NSE group improved significantly over time (p 0.03), while the WL group did not (p=0.92). In addition, pain intensity decreased at 3 months in the NSE group (p 0.05). Seven of 13 individuals in the NSE group (three men and four women) demonstrated improved ventral neck muscle interactions after 3 months of neck-specific exercises (p 0.01), showing neck muscle interaction similar to that seen in healthy individuals.
Pain intensity following the ultrasound test was negatively correlated with ventral neck muscle interactions at 3 months for the non-improved individuals in the NSE group (r=0.90, p 0.02). Despite decreased pain, ventral neck muscle interactions were not significantly improved for six individuals in the NSE group. No correlation was found between ventral neck muscle interaction and NDI (r=0.58, p>0.28) or NME (r=0.71, p>0.11).
Conclusion(s): Real-time ultrasonography is a non-invasive method for detecting mechanical muscle function in the multi-layered ventral neck muscles. Ultrasound measurements with speckle-tracking analysis demonstrated that neck-specific exercises improve ventral neck muscle impairment in chronic WAD.
Implications: The results provide important information that can be used in the assessment and diagnosis of patients after whiplash trauma. The results are promising for further evaluation and improvement of neck-specific exercise interventions in individuals with persistent pain and disability following whiplash injury.
Keywords: Ultrasound, whiplash-associated disorders, exercise
Funding acknowledgements: Swedish government RS2010/009, the Swedish Research Council 2014-2982, Centre for Clinical Research Sörmland at Uppsala University DLL-553281, Uppsala-Örebro Regional-Research-Council RFR-384651.
Purpose: To compare the interaction between three ventral neck muscles (sternocleidomastoid (SCM), longus capitis (Lcap) and longus colli (Lco)) after 3 months of NSE versus remaining on a waiting list (WL) without exercise. The purpose was also to determine whether 3 months of NSE improved ventral neck muscle function compared to a model for healthy individuals developed in an earlier study and to investigate the relationship between ventral neck muscle interactions, neck pain, self-reported neck disability, and neck muscle endurance.
Methods: This randomized control study included 26 individuals (NSE: n=13, 10 women and 3 men; median age 41 years, IQR 30-48 and WL: n=13, 11 women and 2 men; median age 40, IQR;27-47) with chronic WAD grade II-III. SCM, Lcap and Lco were recorded by ultrasound during 10 repetitive arm elevations, which often causes increased neck pain in WAD. The first and tenth arm elevations were analyzed with speckle tracking analyses. Ultrasound, pain, self-reported neck disability, and neck muscle endurance were recorded at baseline and after 3 months. The NSE group performed neck-specific exercises twice weekly for 3 months while the WL group remained on a waiting list for 3 months. Differences between muscles and groups were analysed with multivariate statistics.
Results: Significant between-group differences were found for neck muscle interactions at the 3-month follow-up (p 0.03). The NSE group improved significantly over time (p 0.03), while the WL group did not (p=0.92). In addition, pain intensity decreased at 3 months in the NSE group (p 0.05). Seven of 13 individuals in the NSE group (three men and four women) demonstrated improved ventral neck muscle interactions after 3 months of neck-specific exercises (p 0.01), showing neck muscle interaction similar to that seen in healthy individuals.
Pain intensity following the ultrasound test was negatively correlated with ventral neck muscle interactions at 3 months for the non-improved individuals in the NSE group (r=0.90, p 0.02). Despite decreased pain, ventral neck muscle interactions were not significantly improved for six individuals in the NSE group. No correlation was found between ventral neck muscle interaction and NDI (r=0.58, p>0.28) or NME (r=0.71, p>0.11).
Conclusion(s): Real-time ultrasonography is a non-invasive method for detecting mechanical muscle function in the multi-layered ventral neck muscles. Ultrasound measurements with speckle-tracking analysis demonstrated that neck-specific exercises improve ventral neck muscle impairment in chronic WAD.
Implications: The results provide important information that can be used in the assessment and diagnosis of patients after whiplash trauma. The results are promising for further evaluation and improvement of neck-specific exercise interventions in individuals with persistent pain and disability following whiplash injury.
Keywords: Ultrasound, whiplash-associated disorders, exercise
Funding acknowledgements: Swedish government RS2010/009, the Swedish Research Council 2014-2982, Centre for Clinical Research Sörmland at Uppsala University DLL-553281, Uppsala-Örebro Regional-Research-Council RFR-384651.
Topic: Musculoskeletal: spine; Outcome measurement; Disability & rehabilitation
Ethics approval required: Yes
Institution: Faculty of Health Science Linköping University
Ethics committee: Regional Ethics Review Board,
Ethics number: Dnr 2010/188-31)
All authors, affiliations and abstracts have been published as submitted.
