Transfrontal Interhemispheric Approach And Microsurgical Anatomy Study Of Sellar Area

ObjectiveSellar area's blood vessels and nerves are numerous and anatomical structure are complex, but also sellar area is the highest incidence and the type of the most concen-trated area of intracranial diseases. In this papers, for transfrontal interhemispheric approach and microsurgical anatomy study of sellar area, firstly, we study the ana-tomical structure of the observations, the scope of exposure, advantages and scope of application of transfrontal interhemispheric approach. Thus deepen doctor's under-standing of the fronto-basal interhemispheric approach. Secondly, by microscopic anatomy's observation and measurement of the sellar area, we study the important anatomical structures, anatomical parameters, linkages between them and anatomical variations in the sellar area in order to provide some references for clinical surgery and surgical approaches, moreover, to help the design and improvement of surgical method.MethodsIn this study, under the operating microscope, we simulate sella area's surgery to observe the relevant anatomical structures, exposed areas and measurement data on ten red and blue latex vascular perfusion off cadaveric head specimens transfrontal interhemispheric approach. After surgical approach is completed, we saw all speci-mens along the eyebrow and 1cm on the external occipital protuberance, dissect them, observe, measure and photograph sellar area's bone structure, blood vessels, nerves and adjacent structures under the microscope.ResultOlfactory nerve, optic nerve, optic chiasm, hypophysis stalk, internal carotid ar-tery and its branches, anterior communicating artery complex and the perforating branches can be exposed better via frontal interhemispheric approach, the hypo-thalamus and the terminal plate deep can also be exposed. Under the microscope, the distance from crest to the front of the optic chiasm, hypophysis stalk, intracranial op-tic nerve exit is respectively 39.48±3.55mm,42.35±3.93mm,35.58±3.51mm. five specimens in the group are found to have the clinoid. ligament or the bony structures are often connected among anterior clinoid process, middle clinoid process and poste-rior clinoid process, and three ones have bone connection. The thickness of dia-phragma sellae is different, the thickest one is up to lmm, some are only a layer of transparent film, and 10% diaphragma sellae is absent. The diameter of diaphragma hole is mostly 5.20±1.08mm,40% is more than 5mm.80% sphenoidal sinus are saddle,20% are former saddle, mediated type are no found. The position of the hy-pophysis stalk have the rear-type and free type,70% are the rear-type and are free type in the group. All the specimens, every hypophyseal artery has a constant branch to supply blood to the optic nerve. Supraclinoid carotid artery segment are divided into eye segment, traffic segment and choroidal segment, their diameter are respec-tively 7.63±0.75mm,3.78±0.67mm,3.39±0.82mm. ACA-A1 proximal 3mm and its middle 1/3 are few small blood vessels, the two locations can be as temporary blocked sites for ACoA aneurysms. The shapes of ACoA have large variation, which accounted for 80% of the simple type,20% of the complex type. Every ACoA issue 2～6 small arteries, whose diameter is 0.35±0.12mm. These small arteries supply blood to corpus callosum, hypothalamus, optic chiasm, terminal plate and other im- portant regional. Each side of specimens in this group has Heubner artery, whose starting point is mostly within 2mm from ACoA. The distance from anterior optic chiasm to tuberculum sellae is 5.43±0.94mm.80% optic chiasm is normal position, pre-position and post are respectively located 10%. optic chiasm angle has large variation, generally 50°～80°range, optic chiasm angle greater than 100°is gener-ally pre-position and gapⅠis small. But optic chiasm angle less than 55°is generally post-position and gapⅠis large. The distance from terminal plate to prefrontal is 57.62±2.83mm and terminal plate area's is 50.92±2.89mm2.Conclusion1. Transfrontal interhemispheric approach enter sellar area via brain hemisphere natural gap, which not only helps to expose the operative field, but also brain in-jury is the smallest. It does not need to cut the cerebral cortex, so there are no epilepsy and physical dysfunction caused by cortical damage.2. Transfrontal interhemispheric approach not only applies to the diseases of sellar area, the top of sellar area and the former top of sellar area, but also to open ter-minal plate into third ventricle.3. Transfrontal interhemispheric approach can expose lateral wall of the anterior third ventricle under direct vision, so hypothalamus can be protected effectively in the operation.4. The study of microsurgical anatomy provide us the important anatomical struc-tures, anatomical parameters, links between them and anatomical variations in the sellar area. Thus it provides some references for clinical surgery and surgical approaches, moreover, to help the design and improvement of surgical method.