| Objective:1,To study the mechanical parameters and the correlation during cervical rotationalmanipulation. To summarize the mechanical characteristics of cervical rotationalmanipulation.2,To grasp the change rules of the pressures of the cervical nucleus pulposus duringsimulation of traction and different states of cervical rotational manipulation. Toinvestigate the potential mechanism of action of cervical rotational manipulation andthe safe problems during the manipulation.Method:1,Clinical research of manipulation quantization:The in vivo biomechanical method was adopted to measured the mechanical parameters (include the force,the duration and the acceleration) with mechanical measurement appearance during cervical rotational manipulation that performed by the same therapist to 15 patients of radicular type of cervical spondylosis. Then the displacement and the thrust impulse that happened during cervical manipulation can be calculated with mathematical technique. The characteristics of mechanical parameters of cervical rotational manipulation were summarized after analyzing the datum.2,The in vitro experimental test of manipulation simulation:Traction and different states of cervical rotational manipulation were simulated by Material Test System (MTS) in six fresh cervical spines according to the mechanical parameters from clinical quantization and pressures of the cervical nucleus pulposus of multi-segment were measured concurrently with advanced micro-sensor of pressure that inserted into the nucleus pulposus (C2-3,C3-4,C4-5,C5-6,C6-7). Meanwhile, the accelerations during simulative loading of various states were measured with acceleration transducer.Results:1,Clinical research of manipulation quantization: (1) The average value of parameters during cervical rotational manipulation were as follows: The preload force is 15.15±5.11kg; The peak force is 27.24±8.81kg; The thrust force is 14.29±5.15kg; The thrust duration is 114.33±16.98ms; The peak acceleration is -0.35±0.11g; The thrust displacement is 9.34±2.67mm; The thrust impulse is 22.49±7.11Ns;(2) Except the peak acceleration, the thrust duration and the thrust impulse, the mechanical parameters of rotational manipulation were not different between the performance of the left hand and the right (p>0.05);(3) The preload force of rotational manipulation were similar to the thrust force(p>0.05);(4) The preload force, the peak force and the thrust force were of prominent positive correlation(R>0.8, p<0.001) by Pearson correlation analysis.2,The in vitro experimental test of manipulation simulation:(1) There is no significance difference of pressure among different segments of cervical nucleus pulposus in every conditions by one-way anova analysis (P>0.05) .(2) The pressure of cervical nucleus pulposus at the rotational location(0.503±0.261MPa) is higher than that at the physiological neutral position(0.434±0.266MPa) , but there is no significance difference between them by Paried-Sample t test (P>0.05) .(3) The pressure of cervical nucleus pulposus after the simulation of traction and manipulation with different conditions decreased evidently (P<0.001 ) .There is significance difference among the pressure of cervical nucleus pulposus after the simulation of traction and manipulation with different conditions by one-way anova analysis (P<0.001) .(4) The pressures of cervical nucleus pulposus after loading of three groups of simulation 50N rotational manipulation and the group of traction at neutral position were significantly higher than other groups' pressures (P<0.05) ; The pressures of cervical nucleus pulposus after loading of three groups of simulation 150N rotational manipulation and the group of traction at the rotational location were slightly higher than the pressures of three groups of simulation 250N rotational manipulation, but there is not statistically significant between them (P>0.05) ?,Conclusion:1,The mechanical characteristics of cervical rotational manipulation was summarized by quantization method. We found:(1) The characteristics of force during manipulation (include preload, peak force and thrust force) were paralleled between the left side operation and the right;(2) The process of cervical rotational manipulation was of a certain rule ,from slow traction to rapidly thrusting, which was that thrust force depended on preload force. The rule may be the key point of cervical rotational manipulation.2,By research of the variance of cervical nucleus pulposus, we found:(1) The pressure of cervical nucleus pulposus increased gradually during the neck was rotated from the neutral position to the locked location. The increased magnitude was comparatively obvious. The nucleus pulposus herniation might be aggravated to induce the adverse reaction or to make the pathogenetic condition more serious. Therefore, it could raise the safe during rotational thrust manipulation by bidding patients to finish the process of neck rotation to the locked location by themselves because the locked condition of the facet joint could be reached at the endurable range according to their feelings' adjustment;(2) The pressure of cervical nucleus pulposus decreased following by the increase of upward extracted force. The descent value of the pressure of cervical nucleus pulposus of simulation 150N manipulation got to 0.426±0.202MPa that probably conduce to return the nucleus pulposus of herniation or to make the annulus fibrosus a comparatively long vertical displacement that relieve the stimulation from compression of the nucleus pulposus of herniation;(3) The force of normal rotational manipulation (the preload traction was 15 newton, the thrut force was 150 newton, the thrust duration was about 100ms) was suitable to safely decrease the cervical nucleus pulposus (the mean descent value was 0.429±0.216MPa);(4) The cervical vertebrae and sofe tissues may be damaged during the rude thrust (the preload traction was 150 newton, the thrust force was 250 newton, the thrust duration was within 150ms). |
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