Method Of Locating Related Bone Structures Of Intradural Subtemporal Anterior Transpetrosal Approach

Object:investigate the precise location of intradural related bone structures through intradural subtemporal anterior transpetrosal approach,in order to provide the evidence for clinical safety,accuracy and rapid drilling of anterior petrous bone and exposing the petroclival region.Method:fourteen dry cadaveric specimens were used in the study,collected from Human Anatomy Center of Soochow University and the Second Affiliated Hospital of Soochow University.Identify the arcuate eminence,petrous apex and the point of lateral margin of petrous ridge-anterior margin of transverse sinus junction,the groove for the greater superficial petrosal nerve and its lateral border,spinous foramen,foramen ovale,trigeminal impression,foramen lacerum in the dry skulls,the line connecting the point of lateral margin of petrous bone ridge-anterior margin of transverse sinus junction and the petrous apex as a baseline named JP,at the same time the parallel line named AP₁crossed the highest point of the arcuate eminence.We try to choose the highest point of the arcuate eminence marked A and the point of lateral margin of petrous ridge-anterior margin of transverse sinus junction marked J as two epidural main anatomical landmarks,which we respectively measured the shortest distance to the lateral margin groove for greater superficial petrosal nerve marked AB and JB,to the lateral margin of the foramen spinosum marked AC and JC,to the lateral margin of the foramen ovale marked AD and JD,to the lateral margin of the angular impression of gasserian ganglion marked AE and JE,to the lateral margin of the foramen lacerum marked AF and JF.Also measure the distance JA from the point of lateral margin of petrous ridge-anterior margin of transverse sinus junction to the highest point of the arcuate eminence.Measure the straight line AB,AC,AD,AE,AF crossing line AP₁,respectively to form acute angle?BAP₁,?CAP₁,?DAP₁,?EAP₁,?FAP₁;Measure the straight line JA,JB,JC,JD,JE,JF crossing line JP,respectively to form acute?AJP,?BJP,?CJP,?DJP,?EJP and?FJP.Result:Measurement the results of the dry skull specimens are as follows:AB:11.36±1.27mm?left?,11.46±1.21mm?right?;AC:23.74±1.30mm?left?,24.24±1.01mm?right?;AD:30.40±1.72 mm?left?,30.36±1.57mm?right?;AE:21.36±3.13mm?left?,23.07±2.57mm?right?;AF:31.17±2.38mm?left?,32.99±1.86mm?right?;The value of the left AE and AF was smaller than the right side?P<0.05?.?BAP₁:20.39±3.46°?left?,19.73±4.63°?right?;?CAP₁:26.82±5.32°?left?,26.81±4.70?right?;?DAP₁:21.13±5.11°?left?,20.76±4.62°?right?;?EAP₁:3.55±4.41°?left?,1.99±5.63°?right?;?FAP₁:4.18±4.61°?left?,3.81±3.44°?right?.JA:27.56±2.50mm?left?,27.19±2.75mm?right?;JB:38.23±1.84mm?left?,38.27±2.31mm?right?;JC:47.87±3.09mm?left?,48.74±3.95mm?right?;JD:52.16±5.53 mm?left?,54.11±6.04mm?right?;JE:39.16±2.15mm?left?,39.49±1.84mm?right?;JF:54.21±1.54 mm?left?,51.24±1.55mm?right?;The value of the right JF was smaller than the left side?P<0.05?.?AJP:18.36±4.17°?left?,19.01±3.80°?right?;?BJP:20.88±2.66°?left?,21.80±5.12°?right?;?CJP:23.95±2.83°?left?,23.90±2.57°?right?;?DJP:22.20±3.14°?left?,21.10±1.63°?right?;?EJP:11.04±1.66°?left?,11.69±2.31°?right?;?FJP:7.15±1.65°?left?,7.42±1.51°?right?.Conclusion:The temporal bone structures through intradural subtemporal anterior transpetrosal approach were based on the highest point of arcuate eminence as a main intradural osseous reference points and the point of lateral margin of petrous bone ridge-anterior margin of transverse sinus junction as a intradural secondary osseous reference points,in order to postion intradurally accurately relationship between reference points and most lateral border of the safety greater superficial petrosal nerve,foramen spinosum,the foramen ovale,the lateral margin of the trigeminal impression and foramen lacerum,to define the location of the corresponding neurovascular structure and the extent of the Kawase triangle for reducing the risk of neurovascular injury,to finally provide the basis for the clinical safe accurate and rapid drilling of anterior petrous bone before exposing the petroclival region.