术前螺钉矢状面植入角度设计在Dynesys系统治疗腰椎退变性疾病中的应用

Application of preoperative design of angle to implant pedicle screws on sagittal alignment in treatment of lumbar degenerative diseases with Dynesys system

目的通过对Dynesys动态稳定系统固定术后螺钉在矢状面的夹角分析,提出一种全新的术前螺钉矢状面植入角度设计方法。方法回顾性分析于2018年3月2020年11月接受Dynesys动态稳定系统固定的31例腰椎退变性疾病患者,单节段固定16例,双节段固定15例;其中L_(3-4)节段固定8例次,L_(4-5)节段23例次,L_(5)-S_(1)节段15例次。于手术后第4天下地后行平卧位腰椎CT平扫和重建,测量固定节段双侧相邻螺钉的矢状面夹角和套管长度,并据此提出新的术前螺钉矢状面植入角度设计方法。结果术后CT重建上测得L_(3-4)节段右侧矢状面夹角平均(2.88±1.25)°,左侧平均(3.63±2.00)°,双侧平均(3.25±1.65)°;L_(4-5)节段右侧平均(7.65±3.32)°,左侧平均(8.65±4.93)°,双侧平均(8.15±4.19)°;L_(5)-S_(1)节段右侧(11.47±3.23)°,左侧平均(13.67±4.53)°,双侧平均(12.57±4.02)°。各节段之间有显著性差异(P<0.05)。根据上述测量结果,提出了新的术前螺钉矢状面植入角度设计方法。结论传统Dynesys系统手术后的同侧相邻螺钉矢状面上夹角差异大,新的术前设计可以将矢状面上同侧相邻螺钉植入夹角差异减少一半,更符合Dynesys系统的设计理念。

Objective To introduce a new design to implant Dynesys system by analyzing the angles between two pedicle screws in the adjacent lumbar levels on the sagittal alignment.Methods A retrospective analysis was conducted on 31 patients with lumbar degenerative diseases who underwent fixation with the Dynesys dynamic stabilization system from March 2018 to November 2020.Sixteen patients received single-segment fixation,and 15 patients received double-segment fixation.Among them,8 cases were fixed at the L_(3-4) segment,23 cases at the L_(4-5) segment,and 15 cases at the L_(5)-S_(1) segment.On the fourth day after surgery,when the patients got out of bed,plain lumbar CT scan and reconstruction were performed.The sagittal plane angle and cannula length of the bilateral adjacent screws at the fixed segment were measured,and based on this,a new preoperative screw sagittal plane implantation angle design method was proposed.Results On postoperative CT reconstruction,the average sagittal plane angle for the right side of the L_(3-4) segment was(2.88±1.25)°,and the average for the left side was(3.63±2.00)°,with a bilateral average of(3.25±1.65)°.For the L_(4-5) segment,the average angle for the right side was(7.65±3.32)°,and the average for the left side was(8.65±4.93)°,with a bilateral average of(8.15±4.19)°.For the L_(5)-S_(1) segment,the average angle for the right side was(11.47±3.23)°,and the average for the left side was(13.67±4.53)°,with a bilateral average of(12.57±4.02)°.There were significant differences among the various segments(P<0.05).Based on these measurements,a new preoperative screw sagittal plane implantation angle design method was proposed.Conclusion After the operation of traditional Dynesys system implanting,the angles of adjacent screws in the sagittal alignment varies greatly.The new preoperative design can reduce the angles difference of adjacent screws in the sagittal alignment,which is more in line with the design concept of Dynesys system.