Efficacy of a Lateral Mass Fusion Device Combined with a Three-Dimensional–Printed Model in the Treatment of Craniovertebral Junction Abnormalities

Abstract

To investigate the efficacy of a lateral mass fusion device combined with a three-dimensional-printed model in treatment of craniovertebral junction abnormalities. This retrospective study comprised 56 patients with irreducible atlantoaxial dislocation who underwent posterior fixation between January 2016 and December 2019. Patients were divided into 2 groups according to whether or not cages were used-cage group and autograft group. Visual analog scale score, Japanese Orthopaedic Association score, health-related quality of life, American Spinal Injury Association spinal cord injury grade, atlas-dens interval, space available for the cord, cervicomedullary angle, and fusion rate were compared between groups. Medical follow-up was >1 year. There was no statistical difference between groups in preoperative visual analog scale score, Japanese Orthopaedic Association score, 12-Item Short Form Health Survey score, American Spinal Injury Association grade, atlas-dens interval, space available for the cord, and cervicomedullary angle, and these indexes significantly improved after surgery (P < 0.05). Visual analog scale score and atlas-dens interval were lower in the cage group than in the autograft group (P < 0.05). Japanese Orthopaedic Association score, 12-Item Short Form Health Survey score, space available for the cord, and cervicomedullary angle were significantly higher in the cage group than in the autograft group (P < 0.05). Fusion rate of the cage group 4-6 months after surgery was higher than that of the autograft group (P= 0.068). American Spinal Injury Association grade was significantly higher in the cage group than in the autograft group (P < 0.05). During 1-year follow-up, neurological function improvement and atlantoaxial joint reduction were satisfactory. The lateral mass fusion device combined with a three-dimensional printed model may be a clinically useful technique.