The Finite Element Analysis On The Influence Of Cervical Spondylosis Of Vertebral Artery Insufficiency Type By Cervical Traction

Objective: In order to explore the therapeutic principle of cervical spondylosis of vertebral artery insufficiency type( CSA )by cervical traction and put forward a suitable traction condition to prevent and cure CSA.Method :A cervical spine model of three dimensional finite element model was set up in accordance with measuring figures of cervical spine by autopsy and three planar finite element units were produced according to three X-ray pictures which showed three kinds of cervical radiant pathological changes of cervical lordosis: smaller, straight, kyphosis. 11 kinds of different traction angles from 0 to 30 degrees and 5%^ 10%, 15%, 20% weight of body pull were approached to observe the stress distribution of luschka joints, cervical facet joints and changes of vertical distances among cervical transverses.Results: ( 1 )The stress of normal luschka joints and cervical facet joints was mainly compressive stress which increased from top to bottom, and vertical distances among cervical transverse became slightly narrow at the action of head weight; ( 2 ) when head was in normal or flexion posture, the compressive stress on luschka joints and cervical facet joints could be turned into tensile stress andvertical distances among cervical transverses turned wide ,while in extension posture the stress on them was remain compressive stress and vertical distances turned narrow by traction. The location of maximum stress on the cervical moved downward according to the enhancing of angle. The value of all of them was enlarged with the enhancing of angle and force; ( 3 ) In despite of three kinds of cervical pathological changes, there were the same feature: when head was in normal or flexion posture, the stress of luschka joints and cervical facet joints was still tensile stress and enlarged according to the enhancing of angle and force, the location of maximum stress on the cervical moved downward according to the enhancing of angle.Conclusion: ( 1 ) The therapeutic principle of CSA by cervical traction was that cervical traction withstood the weight of head, turned the compressive stress on luschka joints and cervical facet joints into tensile stress and widened vertical distances among cervical transverses by cervical traction when head was in normal and flexion position; ( 2 ) The suitable traction force were 10%~15% weight of body and angles of cervical traction should be in 0~10 degrees with head was in normal or flexion posture at beginning and the follow selection of angle and force should accommodate to clinical and image diagnoses; ( 3 ) The pathological changes of cervical lordosis had little influence on therapeutic effect.