ABSTRACT
Objective To evaluate the effects of allografi and rhBMP-2 in posterolateral lumbar spinal fusion in a rabbit model.Methods Thirty rabbits were randomly divided into three groups:autogenous lilac crest bone graft group,rhBMP-2/allograft composite group,and allograft group.The animals were killed and sampled six weeks after the surgery.The lumbar intertransverse process fusion for the animals was assessed by manual palpation,biomechanical testing,radiography,histology and quantitative histology of spine fusion mass in a 6-week observation.Results The ratio of fusion in rhBMP-2/allograft composite group(90%)was significantly higher than that in autogenous lilac crest bone graft group(40%)and allograft group(20%)(P＜0.05).The autogenous lilac crest bone graft group and rhBMP-2/allograft composite group showed significantly higher uniaxial tensile strength than allograft group.The au- togenous lilac crest bone graft group and rhBMP-2/allograft composite group also showed significantly more new bone formation than allograft group,but there was no significant difference between the former two grnups.Conclusion rhBMP-2/allograft composite may be an ideal substitute for autograft in lumbar spinal fusion.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the effect of external fixator and reconstituted bone xenograft (RBX) in the treatment of tibial bone defect, tibial bone nonunion and congenital pseudarthrosis of the tibia with limb shortening.</p><p><b>METHODS</b>Twenty patients (13 males and 7 females) with tibial bone defect, tibial bone nonunion or congenital pseudarthrosis of the tibia with limb shortening were treated with external fixation. Two kinds of external fixators were used: a half ring sulcated external fixator used in 13 patients and a combined external fixator in 7 patients. Foot-drop was corrected at the same time with external fixation in 4 patients. The shortened length of the tibia was in the range of 2-9 cm, with an average of 4.8 cm. For bone grafting, RBX was used in 12 patients, autogenous ilium was used in 3 patients and autogenous fibula was implanted as a bone plug into the medullary canal in 1 case, and no bone graft was used in 4 patients.</p><p><b>RESULTS</b>All the 20 patients were followed-up for 8 months to 7 years, averaging 51 months. Satisfactory function of the affected extremities was obtained. All the shortened extremities were lengthened to the expected length. For all the lengthening area and the fracture sites, bone union was obtained at the last. The average healing time of 12 patients treated with RBX was 4.8 months.</p><p><b>CONCLUSIONS</b>Both the half ring sulcated external fixator and the combined external fixator have the advantages of small trauma, simple operation, elastic fixation without stress shielding and non-limitation from local soft tissue conditions, and there is satisfactory functional recovery of affected extremities in the treatment of tibial bone defects, tibial bone nonunion and congenital pseudarthrosis of the tibia combined with limb shortening. RBX has good biocompatibility and does not cause immunological rejections. It can also be safely used in treatment of bone nonunion and has reliable effect to promote bone healing.</p>