ABSTRACT: Objective: The aim of this study was to assess the degradation characteristics of the biodegradable cervical intervertebral fusion cage [made of polycaprolactone(PCL) and β-tricalcium phosphate(β - TCP) with a mass ratio of 5:5] prepared by 3D printing technology, which provides theoretical basis for clinical application. Methods: The prepared fusion cage was immersed in simulated body fluid, placed in a 37 ℃ incubator, and the immersion solution was changed every two weeks. According to the different immersion time, it was divided into six groups: blank control group, 2 weeks, 4 weeks, 12 weeks, 26 weeks, 52 weeks group. Every cage of each group was dried by vacuum drying at room temperature before and after soaking, then its weight was measured by the same balance, and the weight loss and weight loss rate were calculated. The molecular weight of PCL in each cage was analyzed by gel permeation chromatograph, and the compressive strength was tested by INSTRON universal testing machine. In the blank control group, the samples were placed in sealed containers at room temperature, weighed initially and tested for molecular weight and compressive strength. After 52 weeks, the weight loss rate, molecular weight and compressive strength were calculated. Results: The initial compressive strength of this kind of degradable intervertebral fusion cage was (23.21 ± 2.28 MPa), and the strength did not decrease significantly (18.99 ± 0.49MPa) after 52 weeks of degradation in vitro (P>0.05); the weight loss rate was about 9.23% after 52 weeks(P< 0.05), and the molecular weight of PCL decreased from around 100,000 dropped to around 70,000(P<0.05). Conclusion: The biodegradable intervertebral fusion cage has moderate compressive strength and can be maintained for a long time, which meets the requirements of clinical application. It can be degraded slowly in vitro, and its biodegradation and absorption characteristics in vivo are evaluated to be good. Therefore, its application in human intervertebral fusion surgery is feasible and effective. |