Efficacy comparison of posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or iliac bone graft for atlantoaxial instability

Objective To compare the clinical efficacy of posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or iliac bone graft for atlantoaxial instability. Methods A retrospective case-control study was conducted to analyze the clinical data of 56 patients with atlantoaxial instability admitted to the Sixth Hospital of Ningbo from September 2014 to October 2016. There were 35 males and 21 females, with the age range from 9 to 59 years [(50.3±3.2)years]. A total of 26 patients were treated with posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft (complex group), while 30 patients were treated with iliac bone graft (ilium group). Patients showed different degrees of neck pain and limited neck activity preoperatively. X-ray films and three-dimensional CT examination of the cervical spine were taken before and after operation for evaluating the atlantoaxial reduction, bone graft fusion and internal fixation. The operation time, intraoperative bleeding, bone fusion time, visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) score, atlantodental interval (ADI) and axial symptoms were compared between the two groups, and the complications were recorded. Results Both groups were followed up for 24-30 months, with an average of 27.4 months. In the complex group and the ilium group, the operation time was (2.21±0.25)hours and (2.72±0.26)hours (P 0.05), respectively. In the complex group, the VAS was (5.45±0.69)points before operation, (2.64±0.51)points at the follow-up one month after operation, (0.91±0.7)points at the follow-up 12 months after operation, and (0.45±0.16)points at the follow-up 24 months after operation; and in the ilium group, the VAS was (5.18±0.75)points, (2.45±0.52)points, (1.27±0.19)points and (0.41±0.18)points correspondingly. In terms of VAS, there were significant differences before and after operation within each group (P 0.05). In the complex group, the JOA score was (10.82±0.35)points before operation, (12.73±0.65)points at the follow-up one month after operation, (15.18±0.61)points at the follow-up 12 months after operation, and (15.64±0.15)points at the follow-up 24 months after operation; and in the ilium group, the JOA score was (10.73±1.19)points, (13.01±0.63)points, (14.73±0.91)points and (15.55±0.51)points correspondingly. In terms of JOA score, there were significant differences between before and after operation within each group (P 0.05). In the complex group, the ADI was (2.28±0.59)mm before operation, (1.83±0.56)mm at the follow-up one month after operation, (1.71±0.56)mm at the follow-up 12 months after operation, and (1.59±0.67)mm at the follow-up 24 months after operation; and in the ilium group, the ADI was (2.23±0.60)mm, (1.80±0.18)mm, (1.67±0.69)mm and (1.62±0.53)mm correspondingly. In terms of ADI, there were significant differences between before and after operation within each group (P 0.05). The axial symptom scores were graded as excellent in 23 patients and good in three patients of the complex group while excellent in 21 patients and good in nine patients in the ilium group (P>0.05). There were no patients with spinal nerve injury caused by pedicle screw placement after operation. One patient in the ilium group had incision errhysis and recovered after dressing change, and other patients had no incision infection. Conclusions For atlantoaxial instability, posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or autogenous iliac bone graft can both achieve satisfactory clinical results. The spinous process-muscle-vascellum complex graft has less operation time and intraoperative bleeding than the autogenous iliac bone graft, which can be a feasible alternative operation. Key words: Spinal fractures; Bone transplantation; Fracture fixation, internal