Exploration Of Graft Tunnel During Intracranial External Bypass Surgery And Anatomy Of The Maxillary Artery

Objective:We used Cadaveric head simulation to explore the new graft tunnel of extracranial and extracranial bypass and the diameter of the first and second segments of IMA,so as to provide more options and thoughts for clinical bypass surgery in neurosurgery.?Methods:9(18 sides)cadaveric head specimens were treated with orbital zygomaticosteotomy(the front end of the zygomatic osteotomy should not exceed the zygomatic face,and there were zygomatic branches of the maxillary nerve in the zygomatic face).The temporal muscle was fully turned down with the free zygomatic arch,and the line between the fixed wing point and the mandibular angle was a virtual line,along which the internal side of the temporal muscle was blunt separated,directly to the digastric muscle,and the channel was formed.Finally,in order to measure the diameter of the blood vessels and the distance between the segments of the virtual line,the base of the middle cranial fossa was removed under the zygomatic arch,the parotid gland,the internal pterygoid muscle,the external pterygoid muscle,the pterygoid venous plexus,the first segment of the mandibular branch and the surrounding tissues of the first /second segments of IMA were removed,and the blood vessels were fully exposed.The distance of anatomic position related to virtual line was measured by infusion tube.The diameter of the first and second segments of IMA was measured after the vessels were fully exposed.The probability of type I error was determined as a = 0.05,and t-test was designed.The measured data were sorted out by Excel software.The experimentalresults were described by mean ± standard deviation(x ± s).After statistical analysis,the difference was statistically significant(P < 0.05).?Results:1.The virtual line along the line of pterygoid and mandible angle can be separated downward,and the first and second segments of IMA can also be seen along the virtual line.Further separation showed that the inferior alveolar nerve and lingual nerve went down together,and the medial pterygoid muscle appeared at the back,and the inferior alveolar nerve and lingual nerve went down together,and continued to separate along the virtual line to the digastric muscle.?2.The average diameter of the first segment of IMA is(3.66 ± 0.01)mm,and the diameter of the second segment is(3.24 ± 0.03)mm.Theoretically,the first segment can provide high velocity blood flow.Conclusion:1.In order to reduce the possibility of bending and subcutaneous compression caused by the long pathway from external carotid artery to intracranial bypass,a new tunnel has been successfully explored,which is feasible in anatomy and needs to be further verified in clinical application.2.The average diameter of the first segment of IMA is(3.66 ± 0.01)mm,and the diameter of the second segment is(3.24 ± 0.03)mm.Theoretically,the first segment can provide high flow velocity blood flow,which provides a new thinking and selection possibility for the future progress of IMA to intracranial bypass surgery.