Promoting lumbar spinal fusion by adenovirus-mediated bone morphogenetic protein-4 gene therapy / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To determine whether an adenoviral construct containing bone morphogenetic protein-4 (BMP-4) gene can be used for lumbar spinal fusion.</p><p><b>METHODS</b>Twelve New Zealand white rabbits were randomly divided into two groups, 8 in the experimental group and 4 in the control group. Recombinant, replication-defective type 5 adenovirus with the cytomegalovirus (CMV) promoter and BMP-4 gene (Ad-BMP-4) was used. Another adenovirus constructed with the CMV promoter and beta-galactosidase gene (Ad-beta-gal) was used as control. Using collagen sponge as a carrier, Ad-BMP-4 (2.9 multiply 10(8) pfu/ml ) was directly implanted on the surface of L(5)-L(6) lamina in the experimental group, while Ad-beta-gal was implanted simultaneously in the control group. X-ray was obtained at 3, 6, and 12 weeks postoperatively to observe new bone formation. When new bone formation was identified, CT scans and three-dimensional reconstruction were obtained. After that, the animals were killed and underwent histological inspection.</p><p><b>RESULTS</b>In 12 weeks after operation, new bone formation and fusion were observed on CT scans in the experimental group, without the evidence of ectopic calcification in the canal. Negative results were found in the control group. Histological analysis demonstrated endochondral bone formation at the operative site and fusion at early stage was testified.</p><p><b>CONCLUSIONS</b>In vivo gene therapy using Ad-BMP-4 for lumbar posterolateral spinal fusion is practicable and effective.</p>

Anterior plate fixation for cervical distractive flexion injuries:a biomechanical comparison of different types of design / 中华创伤骨科杂志

Objective To evaluate the safety of dynamic anterior plate fixation for cervical distractive flexion injuries and compare its rigidity between different types of plate design. Methods Twelve sets of cadaveric calf spine were used in this test. All the specimens were made into distractive flexion injury models (C4-C5) ac- cording to Allen's method. After discectomy and grafting, they were randomized into three groups in which Orion, Codman, and Window instrumentations were used respectively. The stiffness of each construct was tested in flexion, extension, lateral bending and axial torsion conditions sequentially. Results Compared with an intact cervical spine, the range of motion (ROM) of an injured cervical spine increased whatever plate was applied. Orion in- strumentation presented stiffness the closest to that of the normal control, except for less torsional stiffness. Codman instrumentation provided stiffness close to that for normal and Orion groups only in lateral bending. Window's was the weakest mad not enough in all kinds of movement. Conclusions Static anterior fixation is the first choice for cervical injuries. Dynamic plate fixation may sacrifice stiffness to some extent, especially when a shifting kind of design is to be chosen.