Management and long-term outcomes of combined atlas-axis fractures

Chen Zhida; Cai Taoyi; Zhuang Hanjie; Jiang Yuanjie; Huang Zhuanzhi; Lin Bin

doi:10.3969/j.issn.1009-4237.2026.02.002

Abstract：Objective To explore the treatment strategies and long-term follow-up effects of combined at-las-axis fractures.Methods A retrospective analysis was conducted on 76 patients admitted to the 909th Hospital with combined atlas-axis fractures from May 2014 to Dec.2020,including 46 males and 30 females.The average age was 48.7 years(range 38-75 years).According to Dickman's classification,there were 30 C1-type Ⅱ odontoid fractures,20 C1-miscellaneous C2 body fractures,15 C1-type Ⅲ odontoid fractures,and 11 C1-Hangman fractures.Based on the C2 fracture types,the stability between C1-C2 and C2-C3 was determined by atlantodens interval(ADI),lateral mass offset(LMO),and C2-C3 angle and displacement:ADI≥5 mm or LMO≥7 mm was considered as instability between C1-C2;C2-C3 angulation≥11° or C2-C3 displacement≥3.5 mm was considered as instability between C2-C3.The unstable segments were fixed with posterior pedicle screws.VAS score,neck disability index(NDI),Frankel grading,and incidence of complications were used to evaluate the long-termefficacy.Radiological imaging was used to assess the bone fusion,angle of local curvature of the cervical spine,and cervical stability.Re-sults Among the 76 patients,29 had stable C1-C2 and C2-C3 and thus received non-operative treatment;the other 47 patients had unstable atlantoaxial fractures and received surgical treatment.All patients were followed up for 67-116 months,with an average of 78.5 months.The VAS score and NDI score at 12 months after surgery and last fol-low-up showed significant improvement compared to the preoperative levels(all P＜0.05).At last follow-up,the Frankel grade was improved by 0 to 2 grades.The local curvature angles of the cervical spine before and 3 d after treatment,and at last follow-up were 27.5°±2.1°,24.4°±1.7°,and 23.8°±1.2°,respectively,showing significantly reduced angles with time(all P＜0.05).The average bone healing time was(5.2±0.5)months,and the incidence of complications was 10.5%(8/76).No severe complications such as deterioration of nerve function,cerebral em-bolism,internal fixation failure,instability of the cervical spine,or cerebrospinal leakage occurred among this case series.Conclusion Based on the C2 fracture type,the stability of combined atlas-axis fractures can be judged by ADI,LMO,and C2-C3 angulation and displacement.The unstable segments should be fixed with posterior pedicle screws,which alleviate neck pain,improve neurological symptoms,and restore cervical physiological curvature,pres-enting with good clinical and radiological long-term results.