Sixty patients undergoing 1-level posterior lumbar interbody fusion (PLIF) were randomized to receive a CaO-SiO2-P2O5-B2O3 glass ceramic (BGS-7) intervertebral spacer or a titanium cage filled with autologous local bone. This study used patients from a previous study. The primary outcome of interest included the bone fusion rate by 3D computed tomography (CT). Additional outcomes of interest included are of bone fusion area inside and outside the cage by CT scan and radiograph, the Oswestry Disability Index (ODI) questionnaire, the Short Form-36 Health Survey (SF-36) quality of life questionnaire, pain on a Visual Analogue Scale (VAS), and the incidence of adverse events. Outcomes were assessed up to 4 years post-operation. The results demonstrated that the rate of bone fusion was not statistically significantly different between the 2 groups. However, the bone fusion area by 3D-CT were all in favour of the BGS-7 spacer group, as well as the fusion area inside the cage but not outside the cage. ODI scores, SF-36 scores, VAS back pain scores, VAS right leg pain scores, and VAS left leg pain scores were all not statistically significantly different between the 2 groups. No adverse events were observed in both groups.