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.

Head-trunk kinematics during high-velocity-low-amplitude manipulation of the cervical spine in asymptomatic subjects: helical axis computation and anatomic motion modeling.

OBJECTIVE: This study aimed to analyze the in vivo 3-dimensional kinematics of the head during cervical manipulation including helical axis (HA) computation and anatomic motion representation. METHODS: Twelve asymptomatic volunteers were included in this study. An osteopathic practitioner performed 1 to 3 manipulations (high-velocity and low-amplitude [HVLA] multiple component technique) of the cervical spine (between C2 and C5) with the patient in the sitting position. During manipulation, head motion was collected using an optoelectronic system and expressed relative to the thorax. Motion data were processed to analyze primary and coupled motions and HA parameters. Anatomic motion representation including HA was obtained. RESULTS: During manipulation, average maximal range of motion was 39° (SD, 6°), 21° (SD, 7°), and 8° (SD, 5°) for lateral bending (LB), axial rotation (AR), and flexion extension, respectively. For the impulse period, magnitude averaged of 8° (SD, 2°), 5° (SD, 2°), and 3° (SD, 2°), for LB, AR, and flexion extension, respectively. Mean impulse velocity was 139°/s (SD, 39°/s). Concerning AR/LB ratios, an average of 0.6 (SD, 0.3) was observed for global motion, premanipulation positioning, and impulse. Mean HA was mostly located ipsilateral to the impulse side and displayed an oblique orientation. CONCLUSION: This study demonstrated limited range of AR during cervical spine manipulation and provided new perspectives for the development of visualization tools, which might be helpful for practitioners and for the analysis of cervical manipulation using HA computation and anatomic representation of motion.

Influence of movement speed on cervical range of motion.

PURPOSE: Cervical range of motion (RoM) has been the subject of many studies. However, only very few of these studies have considered the influence of movement execution speed on the cervical kinematics. The aim of this study is to evaluate the influence of movement speed on cervical RoM. METHOD: Cervical RoM was recorded using an optoelectronic system; 32 healthy subjects performed movements in two modes: the best possible and as fast as possible. OUTCOME MEASURES: The primary movements (flexion-extension, lateral bending, axial rotation) and coupled movements were studied. Paired Student's tests were performed to compare the two modes of movement. RESULTS: The results showed that cervical RoM differed significantly between movement speeds. Amplitudes were higher for each movement (p < 0.001 for flexion-extension, p < 0.001 for lateral flexion, p = 0.008 for axial rotations) when movements were performed as quickly as possible. The range of movements carried out the best possible reached only 95% of those during movements carried out as fast as possible. Concerning coupled movements, an increase in rotational movements coupled to lateral flexion during fast movements was observed. CONCLUSION: The range of motion reported in the literature corresponds to movement carried out in a mode resembling the best possible of our study. Movements made as quickly as possible can display larger motion ranges.

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

BACKGROUND: Investigations on 3D kinematics during spinal manipulation are widely reported for assessing motion data, task reliability and clinical effects. However the link between cavitation occurrence and specific kinematics remains questionable. OBJECTIVES: This paper investigates the 3D head-trunk kinematics during high velocity low amplitude (HVLA) manipulation for different practitioners with respect to the occurrence of cavitation. METHODS: Head-trunk 3D motions were sampled during HVLA manipulation in twenty asymptomatic volunteers manipulated by four practitioners with different seniority (years of experience). Four target levels were selected, C3 and C5 on each side, and were randomly allocated to the different practitioners. The data was recorded before, during and after each set of trial in each anatomical plane. The number of trials with cavitation occurrence was collected for each practitioner. RESULTS: The manipulation task was performed using extension, ipsilateral side bending and contra-lateral axial rotation independent of side or target level. The displayed angular motion magnitudes did not exceed normal active ROM. Regardless cavitation occurrence, wide variations were observed between practitioners, especially in terms of velocity and acceleration. Cavitation occurrence was related to several kinematics features (i.e. frontal ROM and velocity, sagittal acceleration) and practitioner experience. In addition, multilevel cavitation was observed regularly. CONCLUSIONS: Kinematics of cervical manipulation is dependent on practitioner and years of experience. Cavitation occurrence could be related to particular kinematics features. These aspects should be further investigated in order to improve teaching and learning of cervical manipulation technique.