A New Concept for Quantifying the Complicated Kinematics of the Cervical Spine and Its Application in Evaluating the Impairment of Clients with Mechanical Neck Disorders

Abstract

Mechanical neck disorder (MND) is one of the most common health issues and is characterized by restricted cervical mobility. However, traditional kinematic information often focuses on primary movement in the cardinal plane, which seems insufficient to fully determine the kinematics of the cervical spine because of the complexity of the anatomical structures involved. Therefore, the current investigation aimed to modify the concept of the three-dimensional workspace to propose an objective mathematical model to quantify the complicated kinematics of the cervical spine. In addition, the observation evaluated the characteristics of the cervical workspace in asymptomatic and MND groups. Seventeen healthy volunteers and twenty-five individuals with MND participated in the study and executed the motion of circumduction to establish the cervical workspace using an electromagnetic tracking system. The results produced a mathematical model to successfully quantify the cervical workspace. Moreover, MND groups demonstrated significant reduction in the normalization of the cervical workspace with respect to the length of the head-cervical complex. Accordingly, the current study provided a new concept for understanding the complicated kinematics of the cervical spine. The cervical workspace could be a useful index to evaluate the extent of impairment of the cervical spine and monitor the efficacy of rehabilitation programs for patients with MND.

Characteristics of the Motor Units during Sternocleidomastoid Isometric Flexion among Patients with Mechanical Neck Disorder and Asymptomatic Individuals

“…Distinct modulations of motor unit synchronization among patients with MND and asymptomatic individuals observed in the present investigation subscribe to the assertion that patients with MND used altered neuromuscular control strategies to achieve the prescribed task compared to asymptomatic subjects. Since the plastic modulation of motor unit synchronization is generally thought to originate from common synaptic input branched presynaptic neurons [31, 32], it is most likely that the reduction in motor unit synchronization reflects the poor cortico-motoneuronal connections, which would be consistent with decreases in muscular strength and presences of jerky or irregular movements for patients with neck pain [2, 9, 10]. Furthermore, another interesting issue should be further elaborated.…”

Development of the circumduction metric for identification of cervical motion impairment

“…In a separate study, they also found greater spectral entropy in the clinical group. 20,21 Other lab studies have identified that the displacement, 22,23 velocity, 23,24 acceleration, 19,22 and smoothness (jerk index) 17,23 of neck motions in people with neck pain are significantly different from matched controls. However, the usefulness of these approaches has been criticized, as the parameters are sensitive to the envelope of motion and velocity 18,25 and are not accessible for routine clinical practice.…”

Near-Infrared Spectroscopy for Monitoring Sternocleidomastoid Muscular Oxygenation during Isometric Flexion for Patients with Mild Nonspecific Neck Pain: A Pilot Study

“…Multifactorial origins, such as prolonged workloads, poor work postures and even psychological distress, are likely to be associated with this musculoskeletal condition [9][10][11]. Except for cervical kinematic and kinetic aberrations [12][13][14][15][16][17][18][19][20][21], previous electrophysiological findings have demonstrated the appearance of neuromuscular adaptations for patients with neck pain [22][23][24][25][26][27][28][29][30]. Increased activation of the superficial cervical flexor muscles and the upper trapezius [23][24][25][26][27]30] and reduced activation of the deep cervical flexor muscles [27][28][29] account for the compensatory modulation of hyper-activation of the superficial cervical flexor muscles for the weak or inhibited activation of the deep cervical flexor muscles in neck pain patients [25,26].…”