寰椎横韧带断裂对寰枢关节三维运动的影响

Three-dimensional movements of atlanto axial articulation after rupture of transverse atlas ligament

寰椎横韧带断裂将使寰枢关节的稳定性丧失，进而发生寰椎前移位产生对高位颈脊髓的压迫．为进一步明确横韧带断裂后对寰枢关节的生物力学影响，对６具新鲜人尸的枕颈部骨韧带标本，通过外科手术方法，切断寰椎两例横韧带，复制成横韧带断型的模型，采用生物力学方法，定量测定了寰枢关节的三维６种运动方式的运动范围（ＲＯＭ）．结果表明：横韧带断裂后，寰枢关下各方向运动的ＲＯＭ除后伸外其余均有增大，尤以前屈运动ＲＯＭ增加最为明显，由正常的２０．２５°增至损伤后的４０．９１°，增加了５０．５％，临床可表现为寰椎前脱位。平均侧屈和旋转运动ＲＯＭ也有变化，分别增加了７．８８°（４９．１％）和１１．８１°（１９．８％），轴位旋转运动ＲＯＭ的增加主要发生在中性区，但示寰枢关节存在潜在的旋转运动不秘，由于寰枢关节生理状态下的侧屈ＲＯＭ很小，故我们认为横韧带断裂后侧屈ＲＯＭ的增加可能不足以造成对寰枢关节生物力学性质的影响．

The biomechanical features of three-dimensional movements of atlanto axial joint were measured in six fresh cadaver specimens were studied. Bilateral transverse ligament rupture was produced by surgical operation. The range of motion (ROM) in all directions except extension increased after the ligament rupture. ROM in flexion increased from 20. 25 degrees to 40. 91 degrees. The increasement of ROM in lateral bending and axial rotation were respectively 7. 88 degrees and 11. 81 degrees. A potential axial rotation innstability was identified in atlanto axial joinnt. The increasement of ROM in lateral bending movement is not large enough to affect the stability of the atlanto axial joint after the transverse ligament rupture.