Endoscopic Anatomical Study On The Removal Of Anterior And Posterior Clinoid Process Transcranial Keyhole Approach

Part 1 Endoscopic Anatomical Study on the Removal of Anterior Clinoid Process via the Pterional Keyhole ApproachObjective:1.To explore areas such as the posterior clinoid process(PCP)exposed through the subtemporal keyhole hard and inferior approach under neuroendoscopy.2.In order to clarify the anatomical relationship of the tissue structure around the PCP,explore the changes in the anatomical exposure range of the upper petroclinic area after the PCP is removed.It is expected to provide an anatomical reference for removing PCP clinically and exposing its surrounding structures.Methods:Using dry adult skull base specimens on 20 sides of 10 cases,the PCP itself and the linear distance between the PCP itself and the important orifices of the skull base were measured.Under the guidance of neuroendoscope,10 cases of adult wet specimens after perfusion were dissected layer by layer through simulated subtemporal keyhole approach,and the surrounding anatomical structures before and after PCP were observed and marked.Record relevant anatomical data and analyze objectively.Result:1.Simulate the structure of the pterion keyhole approach under the endoscope and the key structures seen in the process of ACP as anatomical landmarks.Including: pterion,sphenoid crest,superior orbital fissure(SOF),optic canal orifice,optic nerve,internal carotid artery(ICA)upper clinoid process,etc.Under the endoscopy,this approach showed a good display of the supra-saddle,para-saddle,paraclindrical,and outer cavernous sinus areas.2.The anatomical structures of the middle cranial fossa that can be exposed include: optic nerve,upper ICA clinoid process,pituitary stem,oculomotor nerve,ICA clinoid part,ICA ring,ophthalmic artery,clinoid space(CS).3.Measurement results: 1.ACP length: 9.29±1.20mm;thickness: 5.21±1.15mm;width: 12.15±2.16mm;2.CS is formed after ACP is removed,and its inner side: 7.92±3.58mm;outer side : 13.18±2.94mm;top side length: 9.47±1.75mm;bottom side length:5.33±1.25mm;height: 10.15±1.47mm;3.Before and after ACP abrasion: optic nerve exposure length: 8.75±2.68 mm and 20.22±1.98 mm;exposed length of internal carotid artery: 9.69±2.81 mm and 14.80±1.87mm;exposed width of optic nerve-internal carotid artery space: 4.36±1.27 mm and 11.57±1.98mm;exposed width of internal carotid arteryoculomotor nerve space: 7.39±2.77 mm and 9.97±2.32 mm.Conclusion::1.Neuroendoscopy through the pterional keyhole combined intradural and extradural approach for the exposure of peripheral blood vessels and nerves after ACP abrasion,especially the exposure of the ophthalmic artery,the length of the optic nerve,the length of the ICA,the width between the optic nerve and the ICA,and the relationship between the ICA and the ICA.The width of the oculomotor nerve is important,and at the same time,it can effectively avoid the damage to the ICA,optic nerve,ophthalmic artery and other important structures when the ACP is removed by simple epidural or subdural abrasion,which improves the safety of the operation and can be used as another mill.A safe and effective solution for removing ACP;2.The increase in the operating range after ACP is removed is essential for the accumulation of the above-mentioned anatomical structures;3.The unique advantages of neuroendoscopy,including deep illumination,no blind corners of the visual field,and clear surgical field,It is fully reflected in the wing point keyhole approach.Part 2 Endoscopic Anatomical Study on the Removal of Posterior Clinoid Process via the Subtemporal Keyhole ApproachObjective:1.To explore the area of superior petroclival area,interpeduncular cistern and superior segment of basilar artery exposed while remove posterior clinoid process(posterior clinoid process PCP)via the subtemporal keyhole approach under neuroendoscope.2.In order to clarify the anatomical relationship of the tissue structure around the PCP,explore the changes in the anatomical exposure range of the superior petroclival region after the PCP is removed.It is expected to provide an anatomical reference for removing PCP clinically and exposing its surrounding structuresMethods:Using dry adult skull base specimens on 20 sides of 10 cases,the PCP itself and the linear distance between the PCP itself and the important orifices of the skull base were measured.Under the guidance of neuroendoscope,10 cases of adult wet specimens after perfusion were dissected layer by layer through simulated subtemporal keyhole approach,and the surrounding anatomical structures before and after PCP were observed and marked.Record relevant anatomical data and analyze objectivelyResult:1.The structures along the infratemporal keyhole approach and the key structures seen during PCP abrasion are used as anatomical markers.Including: zygomatic arch root,tentorium cerebellum,lower midbrain,upper pontine,oculomotor nerve,trochlear nerve,upper clinoid of internal carotid artery and its subsidiary branches: posterior communicating artery,anterior choroidal artery,upper basilar artery and its Affiliated branches: posterior cerebral artery,superior cerebellar artery,etc.;2.At the same time,direct the endoscope to the anterior side to expose the parasellar area and expose the pituitary stem,posterior chiasm and optic tract;3.Measurement results: 1.PCP is long and thick,Widths are: 6.12±1.31 mm,3.75±1.89 mm,5.81±1.52mm;2.The distances from the tip of the PCP to the medial edge of the internal auditory canal,the center point of the optic canal,the circular foramen,the foramen ovale,and the spinal foramen are 38.79 ±2.88 mm,29.55±2.02 mm,30.76±1.75 mm,34.21±3.03 mm,34.21±3.03mm;3.Anatomical distance between important blood vessels and nerves: the vertical distance between ICA and oculomotor nerve is 8.08±1.22mm;posterior communicating artery The distance between(PCo A)and tentorium is 8.61±1.56mm;the vertical distance between the anterior choroidal artery and the anterior branch of the posterior communicating artery is 5.53±0.94 mm.The exposed length of the basilar artery before PCP abrasion was 4.02±1.34mm;after abrasion,its length was 6.83±1.82 mm.Conclusion:1.With the help of endoscopy,the bottom of the middle cranial fossa,tentorium notch area,parasellar area,ventral brainstem,superior petroclival area and other structures are well exposed through the infratemporal keyhole approach;2. Abrasion After PCP,the exposed length of the upper part of the basilar artery increases,and the exposure area of the superior petroclival area increases.It provides opportunities for craniotomy and clipping of the tip of the low basilar artery aneurysm and proximal control of the high basilar aneurysm.It also provides an opportunity for the invasion of the superior petroclival area and Tumors on the ventral side of the brainstem provide complete resection.