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Investigation of the stability system of the scapula in patients with cervical spine disorders

17th February 2012

The following articles were published based on the results:


Altered activity of the serratus anterior in patients with cervical disorders. Helgadottir H, Kristjansson E, Einarsson E, Karduna A, Jonsson H.  J Electromyogr Kinesiol: 2011:21;947-953.


Altered alignment of the shoulder girdle and cervical spine in patients with insidious onset neck pain and whiplash associated disorders. Helgadottir H, Kristjansson E, Mottram S, Karduna A, Jonsson H.  J Appl Biomech, 2011:27(3); 181-191.


Altered scapular orientation during arm elevation in patients with insidious onset neck pain and whiplash associated disorder. Helgadottir H, Kristjansson E, Mottram S, Karduna A, Jonsson H.  J Orthop Sports Phys Ther, 2010:40(12); 784-791.


Abstract:
Clinical reasoning suggests that alteration of the scapular stability system has the potential to create and sustain mechanical dysfunction in the cervical and thoracic spine by inducing compressive, rotational and shear forces to the articular tissues. These disturbances are considered to be an important feature in neck pain and the recurrence of neck pain. Current therapeutic guidelines for patients with cervical spine disorders therefore include analysis and correction of the function of the scapular stability muscles and scapular orientation. The scapular stability system has until now not been investigated in patients with neck pain and due to lack of research in this field, therapeutic guidelines intended to restore normal scapular stability in these patients are based on the results of research on the shoulder. The primary aim of this PhD project was to investigate the scapular stability system in patients with cervical spine disorders and to find out if there is a difference in impairments between individuals diagnosed with insidious onset neck pain (IONP) or whiplash associated disorders (WAD). The scapular stability system was investigated by assessing whether there is a pattern of altered scapular orientation when the arm is resting by the side and during arm elevation. The onset of muscle activation of the scapular stability muscles; trapezius and serratus anterior, when the arm is elevated was also evaluated. The secondary aim was to investigate the alignment of the cervical and thoracic spine in the same cohort. The hypothesis was that patients with cervical spine disorders demonstrate altered orientation of the scapula and altered alignment of the cervical and thoracic spine together with a disturbed onset of muscle activation in the scapular stability muscles. These impairments are based on the diagnosis of IONP and WAD.


A three-dimensional tracking device (Fastrak) and a surface electromyography unit measured scapular orientation, the cervical-thoracic alignment and the onset of muscle activation of the trapezius and serratus anterior in patients with IONP (n=22) and WAD (n=27). A control group was selected for comparison (n=23).  The results revealed altered scapular orientation, altered cervical alignment and altered onset of muscle activation in the scapular stability muscles in the symptomatic groups.  The symptomatic groups demonstrated a significantly reduced retraction of the right clavicle and the WAD group a reduced left scapular upward rotation with arm by the side, compared to the control group. A different manifestation was revealed on the left side between the two symptomatic groups in clavicular elevation and scapular anterior tilt with arm by the side and during arm elevation. The results revealed a significantly delayed onset of muscle activation in the serratus anterior and a decreased cranial angle in the symptomatic groups. No difference was found in the thoracic alignment between the three groups.


These findings reflect inconsistent or poorly coordinated muscle activation which reduces the quality of neuromuscular performance, thus altering normal stability of the scapula in these patients. The decreased cranial angle may reflect a reduced weight bearing capacity of the cervical spine, which occurs, amongst other things, by altered muscle activity in the deep cervical flexors. These changes in the scapular stability system and the alignment of the cervical spine may be an important mechanism for maintenance, recurrence or exacerbation of symptoms in patients with cervical spine disorders.
Clinical importance
The results of this study confirm the presence of an altered dynamic stability of the scapula in patients with cervical spine disorders and demonstrate a difference in the impairments between patients with IONP and WAD. The results suggest that similar disturbances may be found in patients with WAD, as in patients with shoulder disorders (Jull et al., 2008) but imply that patients with IONP may have different impairments than those that have previously been reported in patients with shoulder problems.


One of the most important finding is the reduced clavicular elevation and the reduced scapular upward rotation in patients with cervical spine disorders which may reflect long inefficient upper trapezius (Mottram et al., 2009). These findings highlight the need to explore the relationship between the alignment of the shoulder girdle and altered muscle function.  This information may have important implications for clinical practice as current therapeutic guidelines, intended to restore normal stability of the scapula, often include exercises that reduce the upper trapezius activity but increase the activity of the lower trapezius and serratus anterior. These guidelines are based on results of shoulder studies which demonstrate increased clavicular elevation and upper trapezius activity during upper limb tasks (Cools et al., 2007a; Cools et al., 2007b; Cools et al., 2003; Ludewig & Cook, 2000; Ludewig & Reynolds, 2009). The results of this research demonstrate that these therapeutic guidelines, developed for patients with shoulder problems, are in many cases, not appropriate for patients with cervical spine disorders and might further increase the impairments. They also confirm the need to identify disturbances in the scapular alignment in each subject to provide appropriate treatment (Comerford & Mottram, 2010; Jull et al., 2008; Sahrmann, 2002). Based on these findings it is suggested that guidelines intended to restore normal scapular function in patients with shoulder disorders, as well as the general application of stretches intended to elongate and reduce the activity in the upper trapezius should be reconsidered before they are applied to patients with cervical spine disorders.

References:
Comerford MJ, & Mottram SL (2010a). Diagnosis of uncontrolled movement, subgroup classification and motor control retraining of the shoulder girdle. Ludlow, UK: KC International.
Cools AM, Declercq GA, Cambier DC, Mahieu NN, & Witvrouw EE (2007a). Trapezius activity and intramuscular balance during isokinetic exercise in overhead athletes with impingement symptoms. Scand J Med Sci Sports, 17(1), 25-33.
Cools AM, Dewitte V, Lanszweert F, Notebaert D, Roets A, Soetens B, et al. (2007b). Rehabilitation of scapular muscle balance: Which exercises to prescribe? Am J Sports Med, 35(10), 1744-1751.
Cools AM, Witvrouw EE, Declercq GA, Danneels LA, & Cambier DC (2003). Scapular muscle recruitment patterns: Trapezius muscle latency with and without impingement. Am J Sports Med, 31(4), 542-549.

Jull G, Sterling M, Falla D, Treleaven J, & O'Leary S (2008). Whiplash headache and neck pain: Research-based directions for physical therapies. Edinburgh, UK: Churchill  Livingstone, Elsevier.
Mottram SL, Woledge RC, & Morrissey D (2009). Motion analysis study of a scapular orientation exercise and subjects' ability to learn the exercise. Man Ther, 14(1), 13-18.
Ludewig PM, & Cook TM (2000). Alterations in shoulder kinematics and associated muscle activity in people with symptoms of shoulder impingement. Phys Ther, 80(3), 276-291.
Ludewig PM, & Reynolds JF (2009). The association of scapular kinematics and glenohumeral joint pathologies. J Orthop Sports Phys Ther, 39(2), 90-104.
Sahrmann SA (2002). Diagnosis and treatment of movement impairment syndromes. St. Louis: Mosby Inc.

Keywords: Review 2012, Research