The Clinical Value Of The Temporal Bone High Resolution CT In Congenital Microtia During The Surgery

Objective To investigate the clinical value of the temporal bone high resolution CT (HRCT) in congenital microtia during the surgery.Method During the CT scanning process,layer thickness 0.625mm,pitch 15,axle-form place lamellar scanning,bone-algorithm,FOV 9.6cm and interval 0.625mm reconstruction were adopted.To collect 15 cases(16 ears) with congenital microtia during 2006.5-2007.7.The CT images of the 15 cases were compared with what were found during the surgery.the anatomic characterisitics of congenital microtia were analyzed.The two-dimensional reconstruction of facial canalwas performed in 4 cases and The SSD of ossicles was performed in 5 cases.Results HRCT could show the tiny characterisitics of temporal bone malformation clearly.The SSD of ossicles showed the malleus,incus,stapes,malleoincudial joint,and incuostapedial joint distinctly.The two-dimensional reconstruction of facial canal showed the running of facial canal directly.(1)15 cases(16 ears) with congenital microtia were performed the CT scanning showed 15 ears with bone of atresia and 1 ear with membrane of atresia in external ear deformity;2 ears with move down of facial nerve horizon including 1 ear with facial nerve horizon riding above stapes,3 ear with shift forward of facial nerve vertical,2 ears with tympanic cavity narrow;4 ear with temporomandibular joint retrusion;3 ear with sigmoid sinus shift forward;2 ears with mastoid dysgasification;2 ears with cerebral duramater droop;1 ear with comer saeptum; ossicular chain deformity showed:5 ears with malleus deformity,4 ears with malleus and incus fusion,7 ears with incus deformity,4 ear with incus and stapes fusion,4 ears with incus-stapes dislocation of joint,1 ear with incus and stapes flexible joint,7 ears with stapes anterior or posterior arch abnormal,1 ear accompaniment micrognathia;this group not found the case of internal ear deformity.(2) compared the result of HRCT with the findings of operation showed that the HRCT had a higher display rate and coincidence to scanning the external auditory meatus,facial nerve bone tube, temporomandibular joint,sigmoid sinus,papilla gasification,cerebral dura mater droop, malleus and incus,reached 75.0%to 87.5%.but to scanning the labyrinthus and stapes had a lower display rate and coincidence,only reached about 62.5%.(3)the surface shaded display(SSD) of auditory ossicle could showed the anatomic structure of malleus,incus and their jointed clearly,could also had a good showed with stapes,malleus-incus joint and incudostapedial joint.(4)postoperative HRCT scanning showed 1 ear external auditory meatus atresia and 1 ear tympanic membrane moved outside.Conclusion:HRCT of the temporal bone has great clinical value on the preoperative evaluate and operative guide.HRCT scanning could obtain the 3-dimensional image of the external ear,middle ear and internal auditory,get the degree and type of atresia of external auditory canal,tympanic cavity,auditory ossicles deformity,the vertical section of facial canal and the minute structure of internal ear;provid operation evidence for aural rehabilitation and the diagnose of congenital microtia.It could conduce to select the modus operandi and raise the congenital microtia operative achievement ratio.Postoperative HRCT also could to evaluate the operative effect.