Posterior single-segmental osteosynthesis with monoaxial screw system for unstable C1 fractures

English Keywords:Atlas fracture  Unstable  Monoaxial screw fixation  Outcome

English Abstract:

  【Abstract】 Objectives: To evaluate the clinical efficacy of posterior single-segmental osteosynthesis with monoaxial screw system for unstable C1 fractures. Methods: A retrospective case series study was conducted to analyze the clinical data of 23 patients with unstable C1 fractures admitted to Henan Provincial People′s Hospital from January 2010 to June 2019. All patients were treated with posterior single-segmental osteosynthesis with monoaxial screw system. There were 15 males and 8 females, aged 21-62 years (38.5±11.3 years). Operation time and blood loss were recorded. Distance between anterior and posterior fracture ends, lateral mass displacement(LMD), basion-dental interval (BDI), the Japanese orthopedic association (JOA) score and visual analogue scale(VAS) were compared before operation, 1 week after operation and at the last follow-up. The perioperative complications and fracture healing were recorded. Results: All the operations were completed successfully. The operation time was 50-136min(93.6±28.1min), and the operative blood loss was 55-223ml(158.5±53.6ml). The patients were followed up for 6-24 months(15.3±8.5 months). Fracture healing was achieved 6-12 months after operation. The distances between the anterior and posterior fracture ends were 6.4±2.3mm and 3.6±1.9mm before operation, and 1.1±0.6mm and 1.9±0.8mm at 1 week after operation, and the differences were significant(P<0.05). The fracture healed at the last follow-up. The LMD, BDI, the scores of JOA and the scores of VAS before operation, 1 week after operation and at the last follow-up were 7.3±2.1mm, 0.5±0.3mm and 0.7±0.5mm, 4.5±1.3mm, 8.2±1.5mm and 7.6±1.6mm, 9.2±2.6, 14.8±1.9 and 15.6±0.9, 7.2±1.8, 2.6±1.5 and 1.5±1.1 respectively. There was significant difference between that at 1 week after operation and that before operation(P<0.05), and between that at the last follow-up and that before operation(P<0.05). There was no significant difference between that at the last follow-up and that at 1 week after operation(P>0.05). There were 2 cases of superficial incision infection and 7 cases of occipitocervical discomfort and limitation of movement, which were cured after conservative treatment. At the last follow-up, there was no internal fixation loosening or fracture. The atlas fracture healed well, and atlantoaxial instability was not found on dynamic X-ray. Conclusions: Posterior single-segmental osteosynthesis with monoaxial screw system for unstable C1 fractures is able to reduce fracture effectively and maintain the height and stability of the occipital-atlantoaxial position, which has good clinical effect.