The effect of recombinant human bone morphogenetic protein-2 in single-level posterior lumbar interbody fusion

The objective of this prospective, randomized controlled trial was to assess both the clinical and radiographic effect of rhBMP-2 in patients treated with a single-level posterior lumbar interbody arthrodesis with polyetheretherketone cages and pedicular screw instrumentation. Forty patients were randomized with a 1:1 ratio. Two patients were excluded. Interbody arthrodesis was performed using cages, which were filled with 8 mg of rhBMP-2 in the study group and 2,5 mL of autologous iliac crest bone in the control group. All patient completed the Oswestry Disability Index, the Short Form-36 and the visual analogue scale pre-operatively and postoperatively at three, six, twelve and twenty-four months. Thin-slice computed tomography scans with coronal and sagittal reconstructions were made in both groups at three, six, twelve, twenty-four and thirty-six months. All CT scans were read by a radiologist blinded to the randomization assignment. The status of the interbody fusion was quantified using the bridging trabecular bone scale. Bone density measurements were performed in three circular areas with a total surface of 30 mm². There were no significant differences in clinical results between the groups at each postoperative visit. Concerning efficacy, fusion was equally achieved when rhBMP-2 was used versus ICBG but bridging trabecular bone formation on the CT scan occurred at a slower rate and interbody bone density was lower within the first year after surgery in the study group. Bridging trabecular bone formation continued beyond 2 years, while bone density was maximal at two years post-surgery. Regarding safety, certain complications were more frequently noted in the study group using rhBMP-2. Vertebral endplate resorption was observed in all study group patients and was not observed in the control group. Vertebral osteolysis was present in 36.8 % of the study group patients and in none of the control group patients. Cage subsidence was seen in one patient with the use of rhBMP-2. No cage migration was notice in either groups. Ectopic bone formation was present in 47.4 % of the study patients and was not observed in the control group. The results of our study suggest there is no link between vertebral osteolysis and ectopic bone formation. Our results are in line with the available scientific literature. Further research should focus on the least effective dose of rhBMP-2 to promote fusion, on optimizing surgical skills, on the idea of a “sealing barrier” and on the optimal behaviour of carrier systems.

Jaar van publicatie:2019

Trefwoorden:Doctoral thesis

Toegankelijkheid:Open