The Experimental Study Of Prefabricated Individulized Titanium Alloy Implant For The Reconstruction Of Cranial Defect Of Infant Dogs Based On Computer Data And Rapid Prototyping Technique

[Background] Cranial defect of different causes is a common disease in clinicalpractice,which is seriously harmful to patient's body and mind and have highincidence. Because of the complicated anatomical structure and irregularthree-dimensional curvature of cranialfacial structure, surgical reconstruction ofmassive defects has always been challenging for craniofacial surgeons.Traditional methods not only require long contouring time, but also largely dependon the experience and skill of the surgeon. Even so, the integrity of the cranialcavity could only be restored to a limited degree, and the aesthetic result isdissatisfactory. As a frontier of advanced industry technique, rapidproto-typing,combining with modern computer, CT and biomaterial, is now widely used inmedical practice.[Objective] The aim of this research is to: (1). explore the method of prefabricated,individualized implant for reconstruction of cranial defect by virtue of thetechniques of computered tomography, computer imaging processing,rapidprototyping and exact prototyping of titanium. (2.) evaluate the feasibilityand safty of prefabricated ,individualized titanium implant for reconstruction ofcranial defect in children.[Materials and methods] The cranial defect animal model was established withinfant beagles(8 weeks,n=6). Based on the data resource from CT(Computered tomography) continuous thin-layer scanning, the individualized implant was prefabricated by three dimensional reconstruction, a serial disposal ofCT imaging, three dimensional curved reconstruction, computer aideddesign, prototyping manufacture of three dimensional cranial model andindividualized implant, and exact foundry of titanium implant. After implanted intothe area, the following items were observed: (1) blood and urine concentration oftitanium was tested with inductively coupled plasma-mass spectrometry(IP-MS) totrace the titanium release. (2) in vitro and vivo CT/MRI scan was performed toevaluate the existence and extent of CT and MRI artifacts caused by titanium alloyimplant. (3) cephalometry was performed and the data was analysed to evaluate theeffect of titanium implant on the growth of cranialfacial skeleton.[Results] (1)The three dimensional cranial model can display 3-dimensionalanatomical structure elaborately, intuitively, and tridimensionally. Theindividualized implant is well fitted with the defect area (2) This kind of titaniumalloy implant has good biocompatiablity. Titanium ions released from implantwere deposited in local area. The Titanium ion level in blood does not increase,causing no damage to adjacent tissue. (3)Metal artifacts exist in CT scanning, butnot in MRI. (4)The fixation of titanium implant affected cranialfacial development,with the growth constriction in the operated area.[Conclusion] Prefabricated individualized implant for reconstruction of cranialdefect, basing on CT data and rapid prototyping technique, is feasible, it offersliable strength, exhibits good biocompatibility, low magnetic disturbance and inertchemical feature. Yet, the implant prove to affect the cranialfacial growth in beagles.Surgeons should undertake a careful evaluation of the benefits and risks before thethe usage of this kind of technique in children.