上颈椎结构损伤对C1～C2和C2～C3节段稳定性影响的生物力学研究

摘要

目的 测试Ⅱ型齿状突骨折、Ⅰ型Hangman骨折及C2～3椎间盘损伤对C1～ C2节段和C2～ C3节段稳定性的影响并探讨其临床意义.方法 新鲜成人完整C1～C3标本10具,男5具,女5具;年龄25 ～ 45岁,平均35.7岁.在生物力学试验机上依次按照对照组(正常状态)、Ⅰ型Hangman骨折组、Ⅱ型齿状突骨折组、Ⅰ型Hangman骨折+Ⅱ型齿状突骨折组、Ⅰ型Hangman骨折+Ⅱ型齿状突骨折+ C2～3椎间盘损伤组顺序测试C1～C2及C2～C3节段的三维运动范围(ROM)及中性区(NZ),对结果进行统计学分析.结果 Ⅰ型Hangman骨折组与对照组比较,ROMC1～C2在各方向上差异均无统计学意义,且ROMC2 ～C3的左/右侧屈两个方向上差异亦无统计学意义;Ⅱ型齿状突骨折组与对照组比较,ROMC2～C3在各方向上差异均无统计学意义,且ROMC1～C2的左/右旋转两个方向上差异亦无统计学意义;Ⅰ型Hangman骨折+Ⅱ型齿状突骨折组和对照组比较,ROMC1～C2值只在左/右旋转方向上以及ROMC2～ C3值只在后伸方向上差异无统计学意义.Ⅰ型Hangman骨折+Ⅱ型齿状突骨折+C2～3椎间盘损伤组与对照组比较,ROMC1 ～C2值在侧屈和前屈后伸方向上以及ROMC2-C3值在各方向上差异均有统计学意义(P＜0.05).结论 Ⅰ型Hangman骨折丧失了C2～ C3节段在左/右旋转和前屈后伸方向的稳定性,Ⅱ型齿状突骨折丧失了C1～C2节段在左/右侧屈和前屈后伸方向上的稳定性;Ⅰ型Hangman骨折伴Ⅱ型齿状突骨折联合C2～3椎间盘损伤丧失了除寰枢关节旋转功能外C1～ C3节段所有方向的稳定性.本研究可为相关内固定技术的研究和临床治疗提供生物力学依据.%Objective To evaluate the effect of type Ⅱ odontoid fracture,type Ⅰ Hangman fracture,C2-C3 disc injury on stability of C1-C2 and C2-C3 segments and investigate the clinical significance.Methods Ten fresh-frozen cadaveric cervical specimens (5 men and 5 women; 25-45 years of age,mean 35.7 years) were selected to test the stability of C1-C2 and C2-C3 segments in the settings of intact condition (control group),type Ⅰ Hangman fracture,type Ⅱ odontoid fracture,type Ⅰ Hangman fracture + type Ⅱ odontoid fracture,type Ⅰ Hangman fracture + type Ⅱ odontoid fracture + C2-C3 disc injury.Range of motion (ROM) and neutral zone (NZ) of those segments were measured.Results Compared with the intact condition,type Ⅰ Hangman fracture produced no significant variations in C1-C2 ROM in all loading modes and C2-C3 ROM during left and right lateral bending; type Ⅱ odontoid fracture produced no significant variations in C2-C3 ROM in all loading modes and C1-C2 ROM during left and right rotation; type Ⅰ Hangman fracture + type Ⅱ odontoid fracture revealed no significant variations in C1-C2 ROM during left and right rotation and C2-C3 ROM during extention; type Ⅰ Hangman fracture + type Ⅱ odontoid fracture + C2-C3 disc injury produced no significant variations in C1-C2 ROM during left and right lateral bending and extension-flextion and C2-C3 ROM in all loading modes (P ＜ 0.05).Conclusions Type Ⅰ Hangman fracture can reserve C1-C2 segmental left and right rotation and extension-flextion; type Ⅱ odontoid fracture can reserve C1-C2 segmental left and right lateral bending and extension-flextion; type Ⅰ Hangman fracture + type Ⅱ odontoid fracture + C2-C3 disc injury can reverse atlantoaxial rotationary stability and C1-C3 segmental stability in all directions.This study provides the biomechanical basis for clinical treatments and the related researches of internal fixation.