Maeda Takeshi, Saito Taichi, Harimaya Katsumi, Shuto Toshihide, Iwamoto Yukihide
Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Spine (Phila Pa 1976). 2004 Apr 1;29(7):757-62. doi: 10.1097/01.brs.0000113891.27658.5f.
Radiographic analysis of the upper cervical spine was performed in patients with rheumatoid arthritis who had C1-C2 instability.
To assess whether neck retraction or neck protrusion movements can cause C1-C2 subluxation in patients with C1-C2 instability.
Cervical protrusion is the position where the head is maximally translated anteriorly with zero sagittal rotation, and this position has been shown to produce maximal C1-C2 extension. In contrast, cervical retraction is the position where the head is maximally translated posteriorly, and this position produces maximal C1-C2 flexion. To date, there have been no studies evaluating the effects of these two positions on C1-C2 status in patients with C1-C2 instability.
Twenty-four patients with rheumatoid arthritis who showed an atlantodental interval of at least 5 mm during neck flexion were evaluated in this study. These patients were instructed to actively hold the neck in protrusion and retraction positions, as well as in flexion and extension positions. Lateral cervical radiographs were taken to measure the C1-C2 angle and the atlantodental interval in the sagittal plane in each position.
Retraction produced both maximal C1-C2 flexion and anterior C1-C2 subluxation, of a degree just the same as that produced by cervical flexion. Protrusion reversely produced maximal C1-C2 extension. However, 9 of 24 patients exhibited C1-C2 subluxation even in this protrusion position, in marked contrast to the cervical extension position in which only 2 of 24 patients showed C1-C2 subluxation. The patients who showed C1-C2 subluxation in the protrusion position tended to have more severe C1-C2 instability and less capacity for C1-C2 extension than the other patients who achieved a reduction of C1-C2 in the protrusion position.
In patients with C1-C2 instability, not only cervical flexion but also cervical retraction constantly led to both maximal C1-C2 flexion and subluxation. In some patients with severe C1-C2 instability, protrusion also resulted in C1-C2 subluxation, even though the C1-C2 was maximally extended.
对患有C1-C2不稳定的类风湿性关节炎患者进行上颈椎的影像学分析。
评估颈部后缩或前伸运动是否会导致C1-C2不稳定患者出现C1-C2半脱位。
颈椎前伸是头部在矢状面旋转为零时向前最大平移的位置，此位置已被证明会产生最大程度的C1-C2伸展。相反，颈椎后缩是头部向后最大平移的位置，此位置会产生最大程度的C1-C2屈曲。迄今为止，尚无研究评估这两个位置对C1-C2不稳定患者C1-C2状态的影响。
本研究评估了24例类风湿性关节炎患者，这些患者在颈部屈曲时寰齿间距至少为5毫米。指导这些患者主动将颈部保持在前伸、后缩以及屈曲和伸展位置。拍摄颈椎侧位X线片以测量每个位置矢状面的C1-C2角度和寰齿间距。
后缩会导致最大程度的C1-C2屈曲和C1-C2向前半脱位，其程度与颈椎屈曲产生的程度相同。前伸则相反会产生最大程度的C1-C2伸展。然而，24例患者中有9例即使在此前伸位置也出现了C1-C2半脱位，这与颈椎伸展位置形成鲜明对比，在颈椎伸展位置24例患者中只有2例出现C1-C2半脱位。在前伸位置出现C1-C2半脱位的患者往往比在前伸位置实现C1-C2复位的其他患者C1-C2不稳定更严重，且C1-C2伸展能力更弱。
在C1-C2不稳定的患者中，不仅颈椎屈曲，而且颈椎后缩都会持续导致最大程度的C1-C2屈曲和半脱位。在一些C1-C2严重不稳定的患者中，即使C1-C2处于最大伸展状态，前伸也会导致C1-C2半脱位。
