后路寰椎螺钉固定的研究进展

后路寰椎螺钉固定包括寰椎侧块螺钉和寰椎后弓侧块螺钉固定。它们在解剖上是可行的,但需注意椎动脉沟底骨质最薄处的后弓厚度,避免损伤椎动脉及颈内动脉,术前必须常规行寰椎侧位X线及CT扫描帮助确定进钉点及进钉方向。螺钉有较好的拔出力(即使使用单皮质螺钉),并且寰椎侧块螺钉和枢椎关节突间螺钉以及棒连接的结构与经关节螺钉后路钢丝植骨块结构一样稳定。目前较为常用的进钉技术有3种:Harms、Xia、Gupta等的侧块螺钉技术,以及Tan和马向阳等的后弓侧块螺钉技术。临床结果显示:后路寰椎螺钉固定技术能即刻解除脊髓神经压迫、缓解症状,有较好的即刻稳定性,保留枕颈间的运动功能,并且有融合率极高,断钉率、疾病复发以及术后并发症极少等优越性。

Progression of research of posterior screw fixation on atlas

Posterior screw fixation on atlas includes posterior screw fixation within lateral mass of atlas and in atlas via posterior arch and lateral mass.Atlas is anatomically capable for screw fixation in its lateral mass and via its posterior arch and lateral mass.But it is necessary to pay attention to the thickness of the posterior arch at the thinnest part of the groove and avoid injuring the vertebral artery and the internal carotid artery.Routine lateral radiographs and CT scans of the cervical spines of patients must be performed before surgery,which can be of definite help in locating the entry point and regulating the screw direction.The screws have good pullout strength(even when placed unicortically),and constructs using C_1 lateral mass screws and C_2 pars screws connected with rods are as stable as transarticular screws with posterior wire-graft constructs.At present there are three popular techniques:the Harms technique,as well as Xia and Gupta,which is screw fixation within lateral mass of atlas,and the Tan and Ma technique,which are both screw fixation in atlas via posterior arch and lateral mass.Clinical results showed that posterior screw fixation on atlas could relieve spinal and neural oppression immediately,improve clinical symptoms,have good immediate postoperative stability,keep the movement of occipitocervical region,and showed its advantages in very high successful fusion rate,and very few instrument failure,morbidity and complications.