ABSTRACT
<p><b>OBJECTIVE</b>To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies.</p><p><b>METHODS</b>A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engineering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its corresponding vertebra were manufactured using the rapid prototyping technique.</p><p><b>RESULTS</b>The accuracy of the drill template was confirmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to customize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill template fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the personalized template. During surgery, no additional computer assistance was needed.</p><p><b>CONCLUSIONS</b>The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.</p>
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Bone Screws , Imaging, Three-Dimensional , Lumbar Vertebrae , Diagnostic Imaging , General Surgery , Orthopedic Procedures , Surgery, Computer-Assisted , Tomography, X-Ray ComputedABSTRACT
<p><b>OBJECTIVE</b>To investigate the influence of gene transduction mediated by lentivirus vector on human CD34+ cord blood cell (CBCs) gene expression.</p><p><b>METHODS</b>CD34+ cells were isolated and transduced with the third-generation self-inactivating ( SIN) lentiviral vector carrying green fluorescent protein (GFP). The total RNA from transduced cells was extracted and the differences of genotypes between the transduced and non-transduced CD34+ cells were determined with cDNA microarray analysis.</p><p><b>RESULTS</b>In 23000 genes two were upregulated and six downregulated. These changes were not confirmed by semi-quantitative RT-PCR method.</p><p><b>CONCLUSIONS</b>Lentiviral vector used in this study do not influence significantly on the gene expression of CD34+ CBCs, and the vector system may be a useful and safe one in clinical gene therapy.</p>