Clinical Application Of Three-dimensional CT And Cephalometric In The Lateral Cranial Base Tumors

Neoplastic lesions of the lateral cranial base represent a particularlydifficult problem to the clinical diagnosis and therapy, due to their anatomicalcomplexity,topographical location and the close proximity of vital structures suchas the internal carotid artery and cranial nerves.The study reviewed 9 maxillfacialtumor cases involving lateral cranial base and therapy via vertical mandibularramus osteotomy approach.We used three-dimensional CT(3DCT) reconstructionto display the normal anatomy of the lateral skull base,study the presentation ofthe tumors in 3DCT,compare the difference between 3-D quantitativecephalometric and anthropo-logical measurement.This article was divided intotwo parts.We study the three-dimensional reconstruction and cephalo metric of thenormal skull base by spiral CT in the first part.32 normal native adults and 17cranium specimens were selected.First we performed thin slice CT on them,thentransferred the dare to the workstation to reconstruct three-dimensional images,themethod of reconstruction was the shaded surface display. On the reconstructionimages,we watched and measured the main anatomical landmarks of the lateralcranial base;meanwhile,the same landmarks of the 17 specimens wee measuredwith the anthropological method.The comparative analysis between two kinds ofmeasuring methods was conducted.The results were as follows:The 3DCT can display the bone structures of the lateral cranial base clearly,the3-D images can be rotated and enlarged or reduced on the screen freely,theanatomical structures of the skull base can be viewed from different angles.The bone landmarks could be demarcated on the 3-D images directly andconveniently.We can measure the distance and area of the landmarks.To cranium specimens,the 3-D cephalometric results were larger than thoseof anthropological measuremen,bat there were no any statistics differencesbetWen matching pairs of twelve measurement items of t methods(P>0.05).The mean differences betWCen the 3-D measuremed results of native adultsand the anthrOPological measurement resultS of cndum specimens had a standarddeviation smaller than 2 nun,three were satisfactory agreemellt betwCen the twOkinds of measuring methods(P>0.05).We inveStigated the surgical method to theraPy maxillfacial tUInors involvingthe lateral credal base and the clinical value of 3DCT to the surgery in the secondpart. Reviewing 9 neoplastic lesions invoIving lateral skull base,reconstrUcting thebone and soft tissues of twO cases sePotly,dying the bone with yellow colourand Anor with red,and then overiaPPing them.We Studied the anatomicalrelations betWeen the lesions and the adjacen bones,measured the volum of theAnor tissue of one cases on the 3-D images,in order to help the doctor to evaluatethe size of the tumor before swnery and design the surgical plan.the results show:The vertical mandibular ramus osteotorny aPProach gives a wilder eXPosure ofthe SUrgical field,a shorter dePth of work,a good control over the vessels and candisPlay the deePer strUCtUr of the temPoromandibular joint.ComParing with otherlateral aPProach,the vertical mandibular rams osteotomy aPProach retaln the'mandibular vessel and nerve,reduce the smpery comPlications,imPrve the Iivingquality of the patienis.3DCT can disPlny the bone erosions due to the lateral cranial base lesions.WereconstrUcted the bone and lesion resPectively and combined them.The combinedimages could diSPlay the relations betwCen the lesion and bone smictUres clearyand directly,allow the doctors to preview the shaPe and size of the lesion.It isimPoM for the dictors to lay down theraPy plan and cany out oPertion.The conclusions can be drawn as follows:3DCT can disPlay the bone strUCtUre of lateral cranial base cleary anddirectly,dePict the anatomy and pathology of the skull base from differentangles,demonStrae the anatomical relationships between the lesions and adjacenbones,provide many infor...