Study On Three-dimensional Visualization Of Wrist Then Apply It To Design Lunate Prosthesis

ObjectiveTo study the anatomic details and straits of MRI of the bone and ligments of wrist joint and to find out the best coronal plane through contrasting MRI and slice dissect.We demonstrate morphology evidence for imageology diagnosis of wrist disease,we construct the three-dimensional visualization model,observe the 3-D structure of bone and ligment and provide a anatomic basics for computer-aided joint surgery operation when we get the data of on the section of wrist in coronal plane.We can design a prosthesis of lunate bone which is fit to Chinese because the model provide a reliable anatomic data.Method1.Fresh adult wrist which have no visible disease(the chineses visible human 10case and wrist joint samples 12 case) were choosed,then we embed these speciments in rest position in blue gelatine(12 case in traverse,10 case in coronal) and slice these speciments to 0.2mm in low temperature.2.A set of continuous slice data of wrist in coronal were choosed,then we match these picture exactedly and transfer the file format then contrast the MRI and slice picture in coronal plane.3.After being recognized and segmented by the Photoshop software,data of each important part of wrist joint's structures including radial bone,ulnar bone,scaphoid bone,lunate bone,pyramidal bone,pisiform bone,trapezium,trapezoid,capitate bone,hamate bone,metacarpal bones(5 case),radial-ulnar ligament,(triangular fibrocartilage TFC),TFC homologue,radiolunate ligament,radiotriangle ligament,scaphocapitate ligament,radioscaphocapitate(RSG) ligment,scapholunate interosseous(SLI) ligament,lunotriquetral interosseous(LTI) ligament,ulnotriquetral(UT) ligament,ulnolunate(UL) ligament,triquetralcapitate ligament and hamatecapitate ligament,were divided and drawed to reconstruct three-dimensional structures.4.We observe the sharp of lunate bone and the space in wrist and research the stabilization factors of lunate prosthesis to measure anatomic parameter of lunate then calculate and analysis the equation of the two curves of proximal and distal of lunate.5.Measure the anatomic parameter of lunate bone(22 cases) in 3-D visual model of wrist,we design 2 important curve equation of lunate prosthesis through calculation and statistic analysis.We obtain horizontal imaging of fresh lunate(4 cases) in the way of traditional anatomy way and construct the same coordinate system in Photoshop then check value y of dissect and curve equation of lunate bone in the same value x by the way of statistic.Then we study wether it is scientific and feasible to design lunate bone prosthesis in 3-D visual model of wrist.Result1.We obtain 22 sets section data of wrist(Coronal section 10 case,transsection section 12 case),the resolution of sectional image reaches to 6.30 million pixel,corresponding 24bit section imaging file are 36MB(TIFF format).we can observe the inside structure of wrist because the tissue structure do not move and deform.2.The picture exhibit clearly distal radioulnar joint(DRUJ),radiocarpal joint,mediocarpal joint,carpus intercarpal joints and the ligaments in coronal plane.We can get the best coronal MRI plane of intercarpal ligament,TFC,distal radioulnar joint ligament.3.We can reconstruct the main anatomy constructe of wrist in 3-D.This reconstructed structure can be showed in multi-structure or multi-color model,and this structure can be rovotate in random axis in 3-D and display transparently,zoom optionally,and measure any structure precisely.4.It analyzes the vital elements which easily cause the dislocation of prosthes after the substitution of lunate prosthesis,and it also puts forward the problems that should be noticed during the process of the substitution of lunate prosthesis.5.Trimentional visual mode and traditional anatomical methods are applied to get the concave curvilinear equation of capitatelunate joint needed in designing lunate prosthesis and the convex curvilinear equation of radiallunate oint.We analyse the value y in the same value x.Value y of curve equation of lunate bone and dissec do not show obvious difference.So we can draw the conclusion that the curve equation of lunate bone is ture and effective.Conclusion 1.Successive coronal film section could well display intercarpal relations,ligament of articulatio radiocarpea,intercarpal ligament,TFC and DRUJ.Doing researches according to corresponding coronal MRI pictures,we can thoroughly find out the morphologic characteristics and the regularity of changes of interior subtle structure during knee joint in movement and provide the anatomic data for the MRI imaging diagnosis of wrist joint illness.2.Trimentional visual mode can intuitionally reappear the spatial patterns,relations and dischatge regimes of the fine structure inside the wrist joint,which is fundamental to the analysis of wrist's movement mechanism and the morphological reasons for its lesion, etc.Besides,It can be useful for function and three-dimensional direction for the arthrosis surgical navigation in knee joint region,providing the morphologic base for virtual surgery.3.With the trimensional visual mode of wrist joint,we can make a precise measurement for all structures.Through surveying the fine structure of the lunate section we can get the vital factors which maintain the stability of lunate bones and the two important curved equations.Curvilinear equations got from traditional anatomical approaches are true and precise,and the designing approach of lunate prosthesis in the experiment can be proved by the equation,which results that the two approaches keep a good consistency.Therefore, lunate curvilinear equations got from the trimensional visual mode approach supply the design and production of lunate prosthesis with reliable,available parameters.