Author: Ngan, Jim M. W
Title: Kinematic study of spinal manipulation
Degree: M.Phil.
Year: 2003
Subject: Hong Kong Polytechnic University -- Dissertations
Spinal adjustment
Spine -- Movements
Department: Jockey Club Rehabilitation Engineering Centre
Pages: xii, 111 leaves : ill. ; 30 cm
Language: English
Abstract: Spinal manipulation has long been used for the management of spinal disorders. It is a manual technique whereby a therapist applies an accurately determined and specifically directed manual force to the spine to produce some therapeutic effect. Although spinal manipulation is widely used in the management of neck and back pain, its exact mechanism and biomechanical effects are not clear. In the first part of the study, the in vivo kinematics of spinal manipulation were quantified using a 3-dimensional motion analysis system, and inter-rater and intra-rater reliability tests were performed to study the reliability of the kinematic pattern of spinal manipulation. In the second part of the study, the in vitro kinematics of spinal rotation maneuvers were investigated by studying the relative movements of porcine intervertebral joints under different magnitudes and speeds of axial rotation. In the first part of the study, five normal healthy subjects (four females and one male, average age 22.8 years) were recruited. A motion analysis system consisting of four infra-red cameras monitored the relative spatial position and orientation of retro-reflective markers attached to the subject's head and trunk. The maximum voluntary range of motion in flexion-extension, left and right lateral bending and left and right rotation was recorded. The subject was then asked to lie on therapy table, and a right rotational manipulation technique was applied to the C5/6 joint by an experienced physiotherapist after the pre-manipulation position had been located three times. The relative motions of the head and trunk were recorded continuously by the motion analysis system. Three physiotherapists, each with 7 years post qualification experience in spinal manipulation participated in the study. The inter-rater and intra-rater reliability for the kinematics of spinal manipulation were studied. The results showed a consistent kinematic pattern for spinal manipulation, with a small range of de-rotation proceeding a high speed thrust. All manipulations were accompanied by a click sound, which was recorded using an audio receiver. Both of the intra-class correlation coefficient, ICC(3,1), and the inter-class correlation coefficient, ICC(2,1) for time for thrust were low. ICC(3,1) and ICC(2,1) for range of thrust and average thrust velocity were relative high. These relatively high figures indicated that these two parameters during manipulation was subject dependent. ICC(3,1) for range of de-rotation was very high but the ICC(2,1) far range of de-rotation was very low. The result indicated that range of de-rotation was the therapist individual preference. However, a high intra-class correlation coefficient, ICC(3,1) was found for pre-positioning within a single session. In the second part of the study, ten porcine spines from C2 to C4 were fixed and mounted carefully in a materials testing machine so that the axis of the spine at C3 was parallel to the rotational axis of the testing machine. Two potentiometers were used to record the input rotation of the loading head and the rotation at the C3 vertebra. The specimen was rotated in a clockwise direction to a maximum angle of three degrees at speeds between 0.1 and 200 degrees per second. Results showed that the relative rotation at C3/4 was dependent upon the speed and extent of rotation, and rotations of small magnitude applied at speeds between 10 and 50 degrees per second seem most likely to target the appropriate vertebra. This range is close to the average thrust velocities recorded in the first part of the study. However, further work is required to determine the therapeutic mechanism of manipulation, and which kinematic parameters are most important in this mechanism.
Rights: All rights reserved
Access: open access

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