| Objective1. Through the observation、measuring and study compared with microscope by some cadaveric heads specimens of anatomy, the anatomic data about the superior wall of the cavernous sinus and surrounding anatomical structure was acquired to discussed the method and significance of the opening of the superior wall of the cavernous sinus.2. And the highly individualized posterior communicating artery were observed and analyzed to explore the methods and significance of cutting of the posterior communicating artery.3. To provide microsurgical anatomy data of the basilar artery area and explore them advantages and disadvantages of operation, the comparative study of orbitozygomatic-cavernous sinus approach and common Basilar orbito-zygomatic approach was regulated.Methods1. Ten formalin-fixed adult cadaveric heads specimens after perfusion of the arteries an veins with colored silicone were studied under microscope, and photographs were taken from different angle, The superior wall of he cavernous sinus and posterior communicating artery were studied.2. The cadaveric heads specimens were dissected layer by layer under microscope via the orbitozygomatic-cavernous sinus approach to observe and measure the improving exposure of the region of the tip of the basila artery after removing of the anterior clinoid process and posterior clinoid process.3. All date were statistically processed and presented in the mean (range and measured value) style.Results1. Cavernous sinus wall was irregular quadrilateral, the anterior border of the bottom of the former clinoid and sickle dural folds; back boundary of the bed rock ligament, the medial boundary of the saddle across the dural edge, the lateral boundary for the former bedrock ligament and the anterior clinoid outer edge. The superior wall of cavernous sinus include of the anteromedial triangle (Dolenc triangle), the inside triangle (Hakuba triangle)、the carotid triangle and oculomotor triangle. The inside edge of the inside triangle length (8.86±1.97) mm (6.12～15.73mm); lateral side length is (7.50±1.67)) mm (5.92.0～12.56) mm long; behind (5.67±1.81)mm (4.27～11.08mm). There was no nerves and blood vessels pass through in the the superior wall of the cavernous sinus.2. Clinoid space was taper lacuna after anterior clinoid process was stripped, it could provide about0.8～1.2cm3additional operating space. The four length of clinoid space basic margin were8.71±1.72(6.78～10.93) mm、5.23±1.46(4.18～9.05)mn、6.54±1.09(5.01～11.05)mm.9.71±1.65(5.37～14.06)mm respectively, and its height was8.78±1.19(6.32～13.03)mm.3. The clinoid segment of the ICA was between the distal dural ting and the proximal dural ting, with the length of5.93±1.07mm.4. The mater of superior wall of cavernous sinus, including the falciform ligament, clinoid ligament, carotid cave carotid artery collar, oculomotor nerve sheath bag, far-ring and near-ring, internal carotid artery-oculomotor film membrane structure, consisted by shallow and deep two layers, which all are the continuity of the two layers of cavernous sinus lateral wall.5. Posterior communicating artery is divided into three types:embryonic, adult, hypoplasia. A total of70%of all the PComms measured were of the adult type. The external diameter of the internal carotid end of the PCoA averaged1.72±0.77(0.7～4.3) mm in the left and1.69±0.78(0.8～3.3) mm in the right;1.59±0.58(0.8～3.0) mm in the left side of the posterior cerebral end and1.59±0.68(0.5～3.2) mm in the right side of it. In84.2%of the cases, the longest PFZ was located closer to the posterior cerebral artery than to the internal carotid artery.6Measurements were obtained before and after the addition of anterior clinoidectomy, mobilization of the ICA, and posterior clinoidectomy via the orbitozygomatic-cavernous sinus approach. Increases in expansion of the window and exposure of the upper basilar artery were documented as percentages of the control values. The anterior carotid-oculomotor distance averaged50percentage before and after the additional surgical steps to expand the window, respectively. The posterior carotidoculomotor distance averaged35percentage before and after the additional surgical steps to expand the window, respectively. The exposed length of the basilar artery from the bifurcation to the clip was4.5mm before expansion and7.9mm after expansion.Conclusions1. The superior wall of cavernous sinus include of the anteromedial triangle、the inside triangle (Hakuba triangle)、the carotid triangle and oculomotor triangle. Opened of the superior wall of cavernous sinus, there most of cavernous sinus structures can be exposed, and there was no risk of injured the cranial nerves.2. By drilling the anterior and posterior clinoid process in the orbitozygomatic-cavemous sinus approach, the exposure of superior segment of the basilar artery can be increased. This approach combines the advantages granted by most conventional approaches to aneurysms of the BA bifurcation. The approach is suitable for aneurysms situated at a high, normal, or low position on the BA bifurcation. It exposes a sufficient length of the BA trunk to place a temporary clip.3. The superior wall mater of cavernous sinus are consist of shallow and deep two layers, and it were important of two dural to surgical approach. Stripping dura off the superior wall of the cavernous sinus along the inside edge of the inside triangle, taken posterior clinoid process as the center, and three (medial、lateral and posterior) reflection then exposed the ipsilateral posterior clinoid process and dorsum sellae, thus creating a "人" shaped dural flap. This method can protect oculomotor nerve、basilar artery and pituitary from injury in the process of removing posterior clinoid process, which is the best method of striping the superior wall dural of cavernous sinus for removing posterior clinoid process.4. The adult-type accounted for the vast majority of posterior communicating artery, and the longest perforator-free-zone was located closer to the posterior cerebral artery. when it is needed, division of an adult-type PCom at the longest perforator-free-zone is usually feasible and results in a low risk of compromising the blood flow to the branching perforators of the PComm. |
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