Original research
Cervical Spine Assessment Using Passive and Active Mobilization Recorded Through an Optical Motion Capture

https://doi.org/10.1016/j.jcm.2017.12.004Get rights and content

Abstract

Objective

The purpose of this study was to develop and measure a protocol for evaluation of cervical range of motion (ROM), based on passive mobilization (PM) combined with active mobilization (AM) and recorded through an optical motion capture system.

Methods

Passive and active mobilization were applied to 24 asymptomatic participants. Cervical ROM was recorded in 3 anatomic planes (transversal, frontal, and sagittal) using a precision optical system and a set of rigid bodies placed on the sacrum, spinous processes of the C7-T1 vertebrae, and the head. Three captures were made for each participant, distributed over 2 days. The characteristics of the PM, the interaction with the AM, and the coherence patterns between tests were analyzed. Reliability was studied for these procedures.

Results

The reliability results of the PM were high in all analyzed indices; only flexion showed low values. Reliability of AM was greater than PM for flexion, extension, and lateralization because of the similarity to rotation. No statistically significant differences were found comparing PM and AM techniques.

Conclusion

The authors present a cervical ROM assessment based on combined PM and AM protocols at different sessions. This model demonstrated high reliability, individually and combined, and no differences were detected between PM and AM ROMs. Because the evaluator, instrumentation, and the patient are factors that could influence outcomes, the authors suggest that they be combined in protocols. These protocols could be used to evaluate the functional and structural capacity of patients and inform clinical outcomes.

Introduction

Musculoskeletal disorders of the cervical spine have a high incidence and prevalence and are considered a public health problem, especially in developed countries.1, 2 Although there have been significant contributions in different fields to access cervical spine injury, such as whiplash associated disorder (WAD), several diagnostic tests that assess cervical-area alterations, “whiplash severity grading systems,” diagnostic imaging tools, and scales such as the Quebec Task Force, seem to be insufficient for predicting possible complications of symptomatology.3, 4

The diagnostic difficulty is because traumatic cervical spine injuries and their associated symptoms are diverse. Variables that have been measured to quantify the degree of dysfunction are isometric muscle strength,5 motion velocity, smoothness,6 and cervical range of motion (ROM).7, 8, 9, 10, 11, 12, 13, 14 Because of the relationship between joint dynamics and the dysfunction location,9, 11 the ROM is often used to quantify severity and treatment.7 This index is also used by the American Medical Association4, 15 to assess physical damage; it also is used in specific legislation in countries, such as Spain (Law 35/2015)16 for the assessment of damage caused by traffic accidents.

One method to evaluate cervical ROM uses voluntary patient movements under the instructions of an evaluator, called active mobilization (AM). This type of mobilization does not require physical interaction between the patient and the evaluator17 and provides relevant functional information.18 However, application of AM as an isolated technique is questioned.17, 18, 19 Because of the influence of the patient’s subjectivity motivated by psychosocial factors,2, 20, 21, 22 different types of errors may be observed, and the AM technique has high variability of results and a low capacity to predict chronic symptoms.7, 8, 18 Likewise, it does not provide clinical information to determine structural function.20, 22

Another method is passive mobilization (PM).11, 23 In this case, an external force is induced by the examiner to move specific body parts up to the joint limits while the participant relaxes the joint that is being explored.18, 24 Passive mobilization allows the examiner to assess the “physiological barrier,” the structural information of the joint under assessment, which is useful in clinical decision making for treatments.25, 26, 27 It is assumed that this range is not influenced by psychosocial factors, as in AM, because the captured ROM mainly depends on action and perception of the examiner during the test.22, 28 Therefore, authors have reported a lower variability in the results in applying PM techniques.10, 18

Most PM techniques use subjective analyses based on the examiner’s perception,17 so is not considered the gold standard.7, 17, 18 Consequently, the challenge associated with PM is to provide studies that analyze its properties and characteristics through objective kinematic measurements, enabling its validation as a diagnostic technique.

To validate methodologies based on PM, it is necessary to apply criteria related to accuracy and reliability.29, 30 The criteria involve some standards satisfying reliability, which require that the measurement must be repeatable and invariant to external factors (ie, the subjectivity of the evaluator, technical-system commitment, and others).

In a systematic review7 of 46 reliability studies and 21 validation studies where PM and AM techniques were applied, 8 PM studies were found, which described the passive technique used.31 There is a problem when explaining the characteristics and properties using PM combined with objective measures. In general, PM reliability has not been analyzed in depth,7, 8, 32 and only a few have used objective measurements for the analysis of PM techniques.12, 17

If AM and PM were combined for assessment, they could possibly provide greater sensitivity and specific diagnostic information in the clinical-care setting. In addition, the problem concerning the subjectivity of both, which is derived from the evaluator in the PM and is derived from the psychosocial factors of the participant in the AM, might be mitigated by their combination.

Motion capture (MoCap) systems provide precision; however, they are not exempt from sources of errors, such as those derived from the marker placement on particular anatomic areas that move with respect to the underlying bones and those due to the conditions of application in a specific area or use conditions in a specific field.33 The evaluator’s ability to perform a correct grip on the patient is a critical aspect in the measurement of the ROM movements during PM, where the reflective markers can be hidden or even moved by the evaluator if he or she is not sufficiently trained. Consequently, the variability of the system depends on the design of the set and its degree of integration, that is, the placement of markers, the checks, the understanding of the movements by the participant, the instructions to the patient, or the training of the evaluator in the use of the system. Therefore, the added value provided by MoCap technologies can be diminished in the clinical setting if the possible sources of error are studied in their practical application, which is the general purpose of this study.

Therefore, the objectives of this study were the following: (1) to develop a cervical ROM assessment protocol based on PM; (2) to check the system reliability using the PM and AM, individually and combined; (3) to perform a comparison of both techniques, PM and AM; and (4) to understand the influence and interactions between tests when applied together.

Section snippets

Instrumentation

Cervical mobility was recorded through a MoCap system composed of the following components: (1) set of 8 OptiTrack cameras (Flex 13, 1.3 PM, 56° field of view, and 120 frames per second) and the OptiTrack Motive 1.9 application (NaturalPoint Inc, 2016), and (2) software motion characterization Move-Human Sensors (University of Zaragoza, Aragon, Spain),34 implemented in Vizard VR Toolkit35 (WorldViz, Santa Barbara, California) virtual reality platform and the intellectual property of the

Results

The results are displayed in graphs in Figure 6 (AM) and Figure 7 (PM), which are generated from the MoCap application. Statistical analysis (Table 2) shows the results of the exploratory analysis and the average for the movements studied in each session. All movements in both types of assessments, PM and AM, fulfilled the normality hypotheses.

Regarding the comparison results between sessions (S1, S2, and S3) by ANOVA, there were no statistically significant differences for the movements

Evaluated Asymptomatic Population

This study is focused on the design of the system and the protocols for cervical spine assessment through ROM measurement. A sample of asymptomatic participants was selected. This was motivated by the specific objectives of this work, where there are factors that influence AM and PM, either alone or in combination. These factors are the technological and operational system, the placement or possible movement of the markers during capture, the clinical protocol of tests, the environment where

Conclusions

The authors present a cervical ROM assessment based on combined PM and AM protocols at different sessions. This model demonstrated high reliability, individually and combined, and no differences were detected between PM and AM ROMs. Because the evaluator, instrumentation, and the patient are factors that could influence outcomes, the authors suggest that they be combined in protocols. These protocols could be used to evaluate the functional and structural capacity of patients and inform

Acknowledgments

The authors wish to thank Dr. J. Manuel Arredondo and Dr. Dolores Ramón from Instituto de Medicina Legal de Aragón for their contributions when defining the study protocols, and Dr. Mar Pardos from INERMAP Instituto de Ergonomia for her support.

Funding Sources and Conflicts of Interest

This project was cofunded by the Government of Aragon, the European Regional Development Fund, and the University of Zaragoza. It also received cofunding from INERMAP Instituto de Ergonomia. The I3A, University Institute of Research of Engineering of Aragon, University of Zaragoza, Zaragoza, Spain provided materials in their Biomechanics Laboratory for this study. No conflicts of interest were reported for this study.

Contributorship Information

  • Concept development (provided idea for the research): A.J.M., G.U., J.J.M.

  • Design (planned the methods to generate the results): A.J.M., J.J.M.

  • Supervision (provided oversight, responsible for organization and implementation, writing of the manuscript): G.U., J.M., J.J.M., M.B.S.-V., A.C.R.

  • Data collection/processing (responsible for experiments, patient management, organization, or reporting data): A.J.M.

  • Analysis/interpretation (responsible for statistical analysis, evaluation, and presentation

References (50)

  • N Assink et al.

    Interobserver reliability of neck-mobility measurement by means of the flock-of-birds electromagnetic tracking system

    J Manip Physiol Ther

    (2005)
  • J Marin et al.

    Research lines to improve access to health instrumentation design

    Procedia Computer Science

    (2017)
  • JM Bland et al.

    Statistical methods for assessing agreement between two methods of clinical measurement

    Int J Nurs Stud

    (2010)
  • DB Adhia et al.

    Validity and reliability of palpation-digitization for non-invasive kinematic measurement–a systematic review

    Man Ther

    (2013)
  • F Ioppolo et al.

    Epidemiology of whiplash-associated disorders

  • L Holm

    Epidemiology of whiplash associated disorders

    Whiplash

    (2011)
  • PC Ramírez et al.

    Detección de exageración de síntomas en esguince cervical: pacientes clínicos versus sujetos análogos

    Trauma

    (2014)
  • TT Chiu et al.

    Evaluation of cervical range of motion and isometric neck muscle strength: reliability and validity

    Clin Rehabil

    (2002)
  • HS Bahat et al.

    Do neck kinematics correlate with pain intensity, neck disability or with fear of motion?

    Man Ther

    (2014)
  • CH de Koning et al.

    Clinimetric evaluation of active range of motion measures in patients with non-specific neck pain: a systematic review

    Eur Spine J

    (2008)
  • PT Dall’Alba et al.

    Cervical range of motion discriminates between asymptomatic persons and those with whiplash

    Spine

    (2001)
  • H Inokuchi et al.

    Neck range of motion measurements using a new three-dimensional motion analysis system: validity and repeatability

    (2015)
  • YS Song et al.

    Validation of attitude and heading reference system and microsoft kinect for continuous measurement of cervical range of motion compared to the optical motion capture system

    Ann Rehabil Med

    (2016)
  • LN Cupona et al.

    Current standards for measuring spinal range of motion for impairment

    J Chiropr Med

    (2003)
  • Official State Bulletin, Head of The State Spain

    Law 35/2015 of September 22: Reforming the system for the assessment of damages caused to people in traffic accidents

    (2015)
  • Cited by (11)

    View all citing articles on Scopus
    View full text