Microsurgical Anatomical Study And Clinic Application Of Type A-Infratemporal Fossa Approach

Objective:The type A-infratemporal fossa approach involves many anatomic structures among which have complex relationships and the report about the Chinese anatomic study related to this approach is rarely.So the objective for this study is to obtain the relevant Chinese anatomical data related to this approach and provide the reference for clinical applications.Methods:Measure the size of jugular foramen and the distance between jugular foramen and surrounding important structures on ten skulls;simulate the type A-infratemporal fossa approach under microscope to study and measure the anatomic structures on ten adult cadaveric heads.Results:1.The distance from external aperture of jugulare foramen to the styloid process root is[(4.17±1.99)(1.16～8.32)]mm,to the stylomastoid foramen is[(6.06±1.71) (3.22～9.08)]mm,to the hypoglossal canal is[(2.41±1.23)(0.66～4.54)]mm.2.The length of tympanic and mastoid segment facial nerve is[(9.66±1.41)(7.68～12.36)]mm and[(16.08±2.15)(13.26～21.56)]mm.The distance from the pyramid segment of facial nerve to lateral semicircular canal is[(1.08±0.41)(0.46～2.26)]mm.3. The distance from jugular bulb to mastoid segment facial nerve is[(6.56±1.81) (3.12～9.28)]mm and the distance from the peak of jugular bulb to the lowest point of posterior semicircular canal is[(3.67±1.27)(1.76～6.58)]mm.There is one case that the jugular bulb is beyond the hypotympanum.4.The length of vertical and horizontal segment of petrous internal carotid artery is[(10.36±2.31)(5.52～14.28)]mm and [(19.41±2.02)(15.22～23.86)]mm.5.The distance from the lowest point of posterior semicircular canal to transverse process of atlas is[(31.22±1.93)(27.86～35.14)]mm; from the vertical segment of the sigmoid to mandibular joint is[(19.17±1.51)(16.58～21.66)]mm;from the mastoid tip to petrous apex is[(53.91±4.82)(49.92～63.32]mm.Conclusion:The type A-infratemporal fossa approach can wildly expose the lesion in posterior part of infratemporal fossa and jugulare foramen and avoid the injuries of craniotomy. This approach is mainly used to resect the lesion under the labyrinth zone,especially for the various types of tumors extradural around the jugular foramen and this approach also can be combined with other approaches to cure the communicans intra and extra cranium tumors.The anatomic measurement results related to this approach is helpful to position the important structures,improve the rate of tumor resection and reduce the occurrence of postoperative complications.