Comparison of the efficacies between autograft, allograft, and synthetic bone graft in anterior cervical discectomy and fusion

English Keywords:Anterior cervical discectomy and fusion  Autogenous iliac bone  Allograft  Hydroxyapatite  Fusion rate

English Abstract:

  【Abstract】 Objectives: To compare the clinical and radiographic outcomes of autograft, allograft, and hydroxyapatite(HA) synthetic bone graft in anterior cervical discectomy and fusion(ACDF). Methods: A retrospective analysis of patients who underwent ACDF in the Third Affiliated Hospital of Southern Medical University from January 2015 to December 2019 was conducted and 107 patients were included involving 164 segments. The patients were divided into autogenous iliac bone group(n=37 involving 53 segments), allograft group(n=46 involving 70 segments), and HA group(n=24 involving 41 segments). The visual analogue scale(VAS) score, neck disability index(NDI), and Japanese Orthopedic Association(JOA) score were used to evaluate the pain and function of cervical spine before operation and at final follow-up. The height of operated segment and sagittal parameters[(C2-C7 sagittal vertical axis(SVA) and C2-C7 Cobb angle] were measured on the sagittal X-ray films of cervical spine to evaluate the subsidence of cage. The clinical outcome was evaluated according to Odom criteria, and fusion status was assessed according to Brantigan score. Multivariate Logistic regression was used to analyze the risk factors of bone graft poor fusion. Results: There was no statistical difference between the three groups in terms of sex distribution, age, duration of disease, body mass index(BMI), rate of diabetes and lesion of endplate, ratio of single and non-single segment operation, operation time, and blood loss(P>0.05). There was statistical difference in the clinical follow-up between autogenous iliac bone group, allograft group, and HA group(41.6±18.4 months vs 26.9±15.7 months vs 31.3±8.4 months, P<0.05). The VAS score, NDI, and JOA score were significantly ameliorated in all the three groups at final follow-up than those before operation(P<0.05). And the final follow-up VAS and NDI were significantly higher in HA group than the other groups(P<0.05). No significant difference was found in the improvement of VAS between the three groups(P>0.05) while the improvement of NDI and JOA in allograft group was better than the other groups(P<0.05). Of the autogenous iliac bone group, allograft group, and HA group, the rates of excellent or good according to Odom criteria were 81.1%(30/37), 84.8%(39/46), and 54.2%(13/24) respectively at final follow-up, and it was significantly lower in HA group(P<0.05); The fusion rates were 94.3%(50/53), 81.4%(57/70), and 31.7%(13/41) and the rates of subsidence of cage were 3.8%(3/53), 4.3%(3/70), and 58.5%(24/41) respectively. The fusion rate of HA group was significantly lower among the three groups(P<0.05), and the rate of cage subsidence was significantly bigger(P<0.05). At final follow-up, the height of operated segment was significantly lower in HA group(P<0.05) and there was no significant difference in sagittal parameters between the three groups(P>0.05). Multivariable analysis confirmed that usage of allograft and HA synthetic bone was the risk factors of poor fusion. Two patients in HA group(8.3%) received revision surgery because of pseudoarthrosis. Conclusions: Bone allograft had a good clinical outcome, high degree of patient-reported satisfaction, high fusion rate, and low risk of subsidence of cage, which could become a decent substitute of autograft in ACDF. HA bone graft had an inferior clinical outcome, low degree of patient-reported satisfaction, low fusion rate, and high risk of subsidence of cage and revision surgery.