A bridging demineralized bone implant facilitates posterolateral lumbar fusion in New Zealand White rabbits

STUDY DESIGN. Randomized controlled animal study. OBJECTIVE. Test the effectiveness of a single-strip demineralized bone matrix with hyaluronan and gelatin. SUMMARY OF BACKGROUND DATA. Demineralized bone matrix is widely used to augment spinal fusion, however, the effect of changing the physical characteristic and carrier is not known. METHODS. Demineralized bone matrix was extracted from the bones of New Zealand White rabbits, and combined with hyaluronan and gelatin to form solid strips. Forty-eight rabbits were randomized into a control and 2 experimental groups. In the control group, fusion was attempted with autograft bone. For group 2, demineralized bone matrix strips alone and for group 3, autograft and demineralized bone matrix strips were used. The fusion was assessed with manual manipulation and radiographs. The volume of the fusion mass was determined from computed tomographic images. RESULTS. By the manual palpation test, the fusion rates were 37.5%, 93.8%, and 100%, for groups 1-3, respectively (P < 0.05). By radiography, the control group fusion rate was 68.7% compared with 100% for the experimental groups (P < 0.05). The mean bone volumes of the fusion mass were 2142.2 ± 318.5, 3132.9 ± 632.1, and 4181.6 ± 609.5 mm for groups 1-3, respectively (P < 0.05). CONCLUSIONS. The demineralized bone matrix-gel strip was able to function as both a bone-graft enhancer and a bone graft substitute in rabbit posterolateral spine fusion.