Wu Xinjie, Qi Yingna, Tan Mingsheng, Yi Ping, Yang Feng, Tang Xiangsheng, Hao Qingying
Department of Spinal Surgery, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China.
Graduate School of Peking Union Medical College, Beijing, 100730, People's Republic of China.
Arch Orthop Trauma Surg. 2018 Jul;138(7):921-927. doi: 10.1007/s00402-018-2929-6. Epub 2018 Apr 21.
To investigate the incidence and risk factors for adjacent segment degeneration (ASD) following occipitoaxial fusion (OAF) for atlantoaxial instability (AAI) in non-rheumatoid arthritis (RA).
The study group comprised 41 patients without RA who underwent OAF due to AAI. Fifteen patients with postoperative ASD after OAF were classified as the ASD group, and the other 26 patients without postoperative ASD were included in the non-ASD group. There were 12 men and 3 women with a mean age of 43.52 years in the ASD group, and 19 men and 7 women with a mean age of 45.31 years in the non-ASD group. The mean follow-up period was 6.1 and 5.9 years in the ASD group and non-ASD group, respectively. Clinical outcomes and plain radiographs were retrospectively reviewed and compared between the two groups.
The difference between pre- and postoperative O-C2 angles in the non-ASD group was significantly greater than that in the ASD group. The C2-7 angles changed significantly between the pre- and postoperative periods. It was suggested that the small O-C2 angle and large C2-7 angle observed in the early postoperative period were risk factors for the development of ASD. We also demonstrated a high incidence of subaxial subluxation (SAS) and swan neck deformity in the ASD group (27 versus 3.8% and 20 versus 0%, respectively).
Under-correction of the O-C2 angle is likely to cause malalignment of the cervical spine, resulting in the development of postoperative ASD, SAS, and swan neck deformity.
探讨非类风湿关节炎（RA）患者因寰枢椎不稳（AAI）行枕颈融合术（OAF）后相邻节段退变（ASD）的发生率及危险因素。
研究组包括41例非RA患者，因AAI接受OAF治疗。15例OAF术后发生ASD的患者被归为ASD组，另外26例术后未发生ASD的患者纳入非ASD组。ASD组有12例男性和3例女性，平均年龄43.52岁；非ASD组有19例男性和7例女性，平均年龄45.31岁。ASD组和非ASD组的平均随访时间分别为6.1年和5.9年。对两组患者的临床结局和X线平片进行回顾性分析并比较。
非ASD组术前与术后O-C2角的差异显著大于ASD组。C2-7角在术前和术后有显著变化。提示术后早期观察到的小O-C2角和大C2-7角是ASD发生的危险因素。我们还发现ASD组下颈椎半脱位（SAS）和鹅颈畸形的发生率较高（分别为27%对3.8%和20%对0%）。
O-C2角矫正不足可能导致颈椎排列不齐，从而导致术后ASD、SAS和鹅颈畸形的发生。
