Background: The combination of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and recombinant human bone morphogenetic protein 2 (rhBMP-2) is widely used for its advantage of rapid recovery and improved bone fusion. However, no previous study has reported the synergistic effect of MIS-TLIF with rhBMP-2 in patients with degenerative lumbar disease (DLD).
Objective: To investigate the radiographic and patient-reported outcomes (PROs) in patients with DLD who underwent MIS-TLIF with and without a low dose of rhBMP-2.
Methods: We retrospectively reviewed 48 patients treated with MIS-TLIF from 2013 to 2016. The patients were classified into the rhBMP-2 group (n = 25) and non-rhBMP-2 group (n = 23). Fusion-related parameters were measured before and after the operation. Clinical data included the numeric rating scale (NRS) score, Japanese Orthopedic Association (JOA) scores, and the MOS 36-item short form health survey (SF-36) score, which were documented to evaluate the effect of surgery.
Results: In the 48 patients who underwent MIS-TLIF, the operated disc was predominantly at the L4/5 and L5/S1 levels. ADH, MDH, and PDH increased significantly in both groups after surgery (P < 0.05). FH improved in the rhBMP-2 group, but not in the non-rhBMP-2 group. There was no obvious improvement in SA in both groups. Furthermore, the SL showed a significant difference in both groups and a significant improvement over the baseline. The LL showed significant improvement in the two groups at the early follow-up (P < 0.05), but the improvement did not persist. Cage subsidence had no significant effect on different subsidence grades. In addition, no differences in cage subsidence were observed in different types of modic change (MC), except for MC 0 in both groups. There was no difference in PROs even though all clinical outcomes improved significantly during the postoperative follow-up period in both groups.
Conclusion: MIS-TLIF with the low doses of rhBMP-2 resulted in an improvement in radiographic and clinical results, but not a longer-lasting restoration for radiographic outcomes. Cage subsidence is not associated with the MC. Further, our clinical data demonstrated no difference between both groups.