Assessment of in vivo 3D kinematics of cervical spine manipulation: Influence of practitioner experience and occurrence of cavitation noise

Developing spinal manipulation psychomotor skills competency: A systematic review of teaching methods

OBJECTIVE

To update the state of the art regarding the acquisition of spinal high-velocity low-amplitude psychomotor skills competency among chiropractors and chiropractic students.

METHODS

Available electronic articles from 5 databases, published between June 2015 and August 2020, were obtained. Eligible studies underwent methodological quality assessments using the Joanna Briggs Institute Critical Appraisal Checklists and Cochrane Collaboration's Risk of Bias Tools.

RESULTS

Fourteen critically appraised studies were identified, including 10 cohort studies and 4 randomized controlled trials. There was no literature excluded due to high risk of bias. The type of augmented devices included a mannequin on a force platform, a computer-connected device, a human analogue mannequin, and a 3-dimensional electrogoniometer with an instrumented spatial linkage.

CONCLUSION

The use of augmented feedback devices such as human analogue mannequins with force-sensing table technology and computer-connected devices is potentially beneficial in the chiropractic curricula and may facilitate student learning and improvement of spinal manipulation. More studies are required to determine whether psychomotor skill aids translate directly into raised competency levels in novice clinicians.

Impact of audible pops associated with spinal manipulation on perceived pain: a systematic review

OBJECTIVES

An audible pop is the sound that can derive from an adjustment in spinal manipulative therapy and is often seen as an indicator of a successful treatment. A review conducted in 1998 concluded that there was little scientific evidence to support any therapeutic benefit derived from the audible pop. Since then, research methods have evolved considerably creating opportunities for new evidence to emerge. It was therefore timely to review the evidence.

METHODS

The following electronic databases were searched for relevant studies pertaining to the impact of audible pops in spinal manipulative therapy: PubMed, Index to Chiropractic Literature (ICL), Cumulative Index to Nursing & Allied Health Literature (CINAHL) and Web-of-Science. The main outcome was pain. Two reviewers independently selected studies, extracted data, and assessed risk of bias and quality of the evidence using the Downs and Black checklist. Results of the included literature were synthesized into a systematic review.

RESULTS

Five original research articles were included in the review, of which four were prospective cohort studies and one a randomized controlled trial. All studies reported similar results: regardless of the area of the spine manipulated or follow-up time, there was no evidence of improved pain outcomes associated with an audible pop. One study even reported a hypoalgesic effect to external pain stimuli after spinal manipulation, regardless of an audible pop.

CONCLUSIONS

Whilst there is still no consensus among chiropractors on the association of an audible pop and pain outcomes in spinal manipulative therapy, knowledge about the audible pop has advanced. This review suggests that the presence or absence of an audible pop may not be important regarding pain outcomes with spinal manipulation.

Kinematics of the head and associated vertebral artery length changes during high-velocity, low-amplitude cervical spine manipulation

Background

Cervical spine manipulation (CSM) is a frequently used treatment for neck pain. Despite its demonstrated efficacy, concerns regarding the potential of stretch damage to vertebral arteries (VA) during CSM remain. The purpose of this study was to quantify the angular displacements of the head relative to the sternum and the associated VA length changes during the thrust phase of CSM.

Methods

Rotation and lateral flexion CSM procedures were delivered bilaterally from C1 to C7 to three male cadaveric donors (Jan 2016–Dec 2019). For each CSM the force–time profile was recorded using a thin, flexible pressure pad (100–200 Hz), to determine the timing of the thrust. Three dimensional displacements of the head relative to the sternum were recorded using an eight-camera motion analysis system (120–240 Hz) and angular displacements of the head relative to the sternum were computed in Matlab. Positive kinematic values indicate flexion, left lateral flexion, and left rotation. Ipsilateral refers to the same side as the clinician's contact and contralateral, the opposite. Length changes of the VA were recorded using eight piezoelectric ultrasound crystals (260–557 Hz), inserted along the entire vessel. VA length changes were calculated as D = (L₁− L₀)/L₀, where L₀ = length of the whole VA (sum of segmental lengths) or the V3 segment at CSM thrust onset; L₁ = whole VA or V3 length at peak force during the CSM thrust.

Results

Irrespective of the type of CSM, the side or level of CSM application, angular displacements of the head and associated VA length changes during the thrust phase of CSM were small. VA length changes during the thrust phase were largest with ipsilateral rotation CSM (producing contralateral head rotation): [mean ± SD (range)] whole artery [1.3 ± 1.0 (− 0.4 to 3.3%)]; and V3 segment [2.6 ± 3.6 (− 0.4 to 11.6%)].

Conclusions

Mean head angular displacements and VA length changes were small during CSM thrusts. Of the four different CSM measured, mean VA length changes were largest during rotation procedures. This suggests that if clinicians wish to limit VA length changes during the thrust phase of CSM, consideration should be given to the type of CSM used.

Toward a Theory of the Mechanism of High-Velocity, Low-Amplitude Technique: A Literature Review

This review seeks to integrate the current literature to create a more unified and inclusive theory regarding the therapeutic mechanism of high-velocity, low-amplitude (HVLA) technique. The authors review the literature currently available regarding the physiologic effects of HVLA. The progression from an articulatory model to a neuromuscular one is discussed, and the body of work demonstrating that HVLA has a centralized mechanism of action, rather than just a local one, is described.

Reaction Force Magnitude and Orientation During Supine Thoracic Spine Thrust Manipulation: An Exploratory Analysis and Reliability of Preload and Impulse Phase

OBJECTIVE

The main purpose of this study was to explore specific kinetic parameters during supine thoracic thrust manipulation and to analyze task reliability and differences between various practitioners METHODS: Kinetic parameters were assessed by examining ground reaction force magnitude and orientation (on the basis of the zenithal angle) using force platforms. The manipulative procedure (consisting of the application of 3 preloads followed by 1 single thrust adjustment) was performed by different practitioners at 3 sessions. Application of thrust was allowed for trained practitioners only. Preload force, peak force, and vector force orientation were compared between sessions and practitioners.

RESULTS

Reliability analysis showed that practitioners achieved similar preload and peak force independent of the session, with comparable force orientation data. Differences between practitioners were observed for preload and peak force but not regarding the zenithal angle during the thrust phase.

CONCLUSION

This study is the first that explores kinetic parameters for supine thoracic thrust manipulation. Task repeatability was confirmed and several differences were observed between practitioners. Certainly, there is a need for further investigation examining both dynamic parameters (ie, velocity and accelerations) and the potential neurologic effect of such manipulative technique.

Relationship Between Subjective Experience of Individuals, Practitioner Seniority, Cavitation Occurrence, and 3-Dimensional Kinematics During Cervical Spine Manipulation

OBJECTIVE

The purpose of this study was to assess individual subjective experience (ISE) of the recipients of a cervical manipulation and to analyze the influence of kinematics, cavitation occurrence, and practitioner seniority on individual experience.

METHODS

Practitioners with different seniority (years of experience) manipulated 20 asymptomatic volunteers at C3 and C5 on both sides. Kinematics were recorded using a 3-dimensional electrogoniometer, and ISE data were gathered through a questionnaire to explore the subjects' experiences of manipulation in terms of tactile sensations, relaxation, perception of the task, and therapist handling. Kinematics, occurrence of cavitation, practitioner's seniority, and ISE data were analyzed concurrently.

RESULTS

Motion parameters obtained during manipulation were found to be influenced by cavitation occurrence and differences between practitioners. Data analysis indicated that ISE could be grouped into 2 factors. The first revolved around grip firmness and range and speed of practitioner's gesture. The second factor represented patient's relaxation and the precision of handling. Also, most ISE data correlated with kinematics, although a subjective measurement did not always correlate the highest with its objective counterpart. When cavitation occurred, ISE ratings were higher, suggesting that participants may associate cavitation with the success of manipulations. Higher practitioner seniority (more years of experience) induced feelings of higher speed, amplitude, firmness, and precision.

CONCLUSIONS

Recipients of cervical manipulation experienced different subjective feelings that can be expressed in 2 dimensions. These feelings are influenced by cavitation occurrence and practitioner's seniority. A better understanding of an individual's subjective experience related to cervical manipulation could increase confidence and improve the patient-therapist relationship, and it may provide further therapeutic perspectives for the practitioners.