The Study Of Micradissection Of Enlarged Translabyrithine Approach And Stereo-imaging Before Operation

To obtain more detailed microsurgical anatomic data about the enlarged translabyrithine approach. Twenty cadaver heads(40sides)fixed with formalin were dissected by mimicking enlarged translabyrithine approach under the microscope . Measurement and observation were performed,there were : the width of the middle part of sigmoid ,the shortest distance between the middle part of sigmoid and the vertical part of facial nerver , the height of jugular bulb , the shortest distance between the highest point of jugular bulb and the base of internal acoustic meatus , the width of external orifice of cochlear aquaduct , the length of cochlear aquaduct , the shortest distance between external orifice of cochlear aquaduct and cranial nerves Ⅸ, Ⅹ, Ⅺ,inferrior petrosal sinus respectively, the shortest distance between external orifice of cochlear aquaduct and the inferior margin of internal acoustic meatus orifice, the width of internal acoustic meatus orifice ,the vertical distance of internal acoustic meatus orifice,the shortest distance between the superior margin of internal acoustic meatus orifice and superior petrosal sinus, the angle between superior petrosal sinus and sigmoid , the diameter of Ⅶ ,Ⅷ nerve,superior vestibular nerve,inferior vestibular nerve,cochlear nerve,Intermedius nerve respectively, mastoid emissary,communicating orifice of superrior petrosal sinus , the nerve and blood vessel of jugularforamen,the branch of anterior inferior cerebelar artery,the condition of labyrinthine artery.The auther used new type multi-slice helical CT to observe the reconstrction of the surface structure of temporal bone,and compared with anatomical specimens to verify the dependability of 3D data.Advanced imaging workstation and big capacity computer　also were applied to make the 3D reconstruction of ear ossicles ,labyrinth ,cochlear,　nerve ,　tumour,　blood vessel et al in order to prepare for imitating operation.The study show that: More attention should be paid on mastoid emissary when dealing with mastoid process.The right side jugular bulb is higher than the left side.There are more high jugular bulbs on the right sides. Cochlear aquaduct can be regarded as an important landmark to tell us how much bone we can move around it. The angle between superior petrosal sinus and sigmoid also shows the range we can resect. The loop of anterior inferior cerebelar artery and Labyrinthine artery have much variation .The jugular foramen always has nature partition. The enlarged translabyrithine approach can give enough vision for crebellopontine angle operation.The new type CT has more rapid speed of 3D reconstruction and clearer imaging.The technique of Shade surface display and Volume rendering can give very clear structure of temporal bone.The 3D data makes no difference with anatomical measurement(no statistic difference).The 3d data can instruct the clinic directly. The Volume rendering technique can reveal the nevers of internal acoustic meatus and membranous labyrith clearly.Double liminal value technique can be used to show different density structureof temporal bone.The best liminal value range : -800±100~±200Hu.After reinforcement the 3D imaging of tumour and blood vessel around it can be seen clearly.This technique can be used to design the approach of surgury.But this technique also has disadvantage which can not show the all structure of temporal bone simultaneously.