Ito Hiromu, Neo Masashi, Sakamoto Takeshi, Fujibayashi Shunsuke, Yoshitomi Hiroyuki, Nakamura Takashi
Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto, 606-8507, Japan.
Eur Spine J. 2009 Jun;18(6):869-76. doi: 10.1007/s00586-009-0945-5. Epub 2009 Apr 1.
The most common cervical abnormality associated with rheumatoid arthritis (RA) is atlantoaxial subluxation, and atlantoaxial transarticular screw fixation has proved to be one of the most reliable, stable fixation techniques for treating atlantoaxial subluxation. Following C1-C2 fixation, however, subaxial subluxation reportedly can bring about neurological deterioration and require secondary operative interventions. Rheumatoid patients appear to have a higher risk, but there has been no systematic comparison between rheumatoid and non-rheumatoid patients. Contributing radiological factors to the subluxation have also not been evaluated. The objective of this study was to evaluate subaxial subluxation after atlantoaxial transarticular screw fixation in patients with and without RA and to find contributing factors. Forty-three patients who submitted to atlantoaxial transarticular screw fixation without any concomitant operation were followed up for more than 1 year. Subaxial subluxation and related radiological factors were evaluated by functional X-ray measurements. Statistical analyses showed that aggravations of subluxation of 2.5 mm or greater were more likely to occur in RA patients than in non-RA patients over an average of 4.2 years of follow-up, and postoperative subluxation occurred in the anterior direction in the upper cervical spine. X-ray evaluations revealed that such patients had a significantly smaller postoperative C2-C7 angle, and that the postoperative AA angle correlated negatively with this. Furthermore, anterior subluxation aggravation was significantly correlated with the perioperative atlantoaxial and C2-C7 angle changes, and these two changes were strongly correlated to each other. In conclusion, after atlantoaxial transarticular screw fixation, rheumatoid patients have a greater risk of developing subaxial subluxations. The increase of the atlantoaxial angel at the operation can lead to a decrease in the C2-C7 angle, followed by anterior subluxation of the upper cervical spine and possibly neurological deterioration.
类风湿关节炎（RA）相关的最常见颈椎异常是寰枢椎半脱位，而寰枢椎经关节螺钉固定已被证明是治疗寰枢椎半脱位最可靠、稳定的固定技术之一。然而，据报道，在C1-C2固定后，下颈椎半脱位可导致神经功能恶化，并需要二次手术干预。类风湿患者似乎风险更高，但类风湿患者与非类风湿患者之间尚未进行系统比较。导致半脱位的影像学因素也未得到评估。本研究的目的是评估寰枢椎经关节螺钉固定术后类风湿患者和非类风湿患者的下颈椎半脱位情况，并找出相关因素。43例行寰枢椎经关节螺钉固定且未同时进行任何其他手术的患者接受了超过1年的随访。通过功能X线测量评估下颈椎半脱位及相关影像学因素。统计分析表明，在平均4.2年的随访中，RA患者比非RA患者更易发生2.5mm或更大程度的半脱位加重，且上颈椎术后半脱位发生在前侧方向。X线评估显示，此类患者术后C2-C7角明显更小，且术后AA角与之呈负相关。此外，前侧半脱位加重与围手术期寰枢椎及C2-C7角变化显著相关，且这两种变化彼此密切相关。总之，寰枢椎经关节螺钉固定术后，类风湿患者发生下颈椎半脱位的风险更高。手术时寰枢椎角增大可导致C2-C7角减小，继而引起上颈椎前侧半脱位，并可能导致神经功能恶化。
