Endoscopic Anatomy And Clinical Research Of Sellar Region Via Pterional Keyhole Approach

Background: Sellar region is the important area where the diseases origin from, including pituitary adenoma, craniopharygioma, epidermoid cyst, meningioma and aneurysm, etc.There are variaties of approaches to the region, and pterional approach is one of them. As the rapid development of microinvasive neurosurgery, the technique of key hole approach and endoscope becomes more and more important., and the combination of both has become a significance mark of microinvasive neurosurgery. Endoscope has been used in assisted microneurosurgery for sellar lesions, especially the development of keyhole technique, endoscope has its typical advantage as a assisted instrument.The anatomy of sellar region is complicated.It's necessary to understand the feasibility of combination of the keyhole technique and endoscopy for sellar lesion's surgery. To know the histology of cranial nerves and vessels and their relationship under endoscope is the basic knowledge for diagnosis and treatment of sellar area lesions by neuroendscope.Objective: To study the endoscopic anatomy of operative fissures in the sellar region via pterional keyhole approach,affirm the anatomic land marks and provide the anatomic basis for endoscope-assisted microneurosurgery in the region. Methods: Five cadaver heads were dissected via pterional keyhole approach and the anatomy in the five operative fissures(Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ) was studied and compared with neuroendoscope and microscope while simulating doing operation in sellar area. Results: In our research, Five cadaver heads (10 sides) were dissected via pterional keyhole approach. The sellar cisterns were dissected under microscope and the anatomy of the five fissures were recorded and observed by 00 and 300 neuroendoscope. According to the anatomic guideposts under neuroendoscope, the microstructures of the five fissures and Willis'circle would be well demonstrated. It is better to display the various anatomic structures in sellar region by neuroendoscope rather than microscope, particularly some important microstructures,for example,the location of the perforating artery. In fissureⅠBilateral optic nerves, optic chiasm, stalk hypophysial and bilateral superior hypophysial arteries can be observed well in the front view and norma anterior under endoscope, especially the ophthalmic artery arising from the medial wall of the heterolateral internal carotid artery(ICA), branches and the superior hypophysial artery. The entire sellae diaphragma can be almost peeked through the keyhole under endoscope.In fissureⅡ, bilateral mamillary body and cerebral peduncle, interpeduncular fossa, perforating artery of thalamus will be well demonstrated by 30°neuroendoscope. In fissureⅢ, when observation of 30°endoscopy is from anterolateral to posterior, the structures will be showed much clear, such as bilateral mamillary body, perforating artery of tharamus, bilateral cerebral peduncle, pons, BA bifurcation, bilateral PcomA and their branches and SCA. In fissureⅣ, endoscopic anatomy shows clear, such as bilateral A1 segment of anterior cerebral artery(ACA), anterior communicating artery(AcomA), Heubner recurrent arteries and perforating arteries. Moreover, the M1 segment of middle cerebral artery, ICA bifurcation and hypothalamic perforating artry arising from AcomA would be observed well. Microanatomy of fissureⅤby endoscope is similar of that by microscope, showing the structures of ICA bifurcation fissure,including A1 segment of ACA and perforating branches,M1 segment and perforating branches,Heubner recurrent arteries,optic tract and temporal lobe fissure.Conclusions:It is better to display the various anatomic structures in sellar region by neuroendoscope rather than microscope, particularly some important microstructures.30°endoscope can be used to observe the structures behind nerves and vessels. According to the anatomic guideposts, an endoscope can be used to enhance the visible field of an operative microscope via pterional key-hole approach. The endoscope-assisted microsurgery can reduce complications and injury of the important structures and increase the curative effect on the lesions in the sellar region. Background: Endoneurosurgery was classified into three types . (1) Endoscopic neurosurgery,EN; (2) Endoscope-assisted Microneurosurgery,EAM; (3) Endoscope-controlled Microneurosurgery, ECM. EN means neuroendoscope is used only and the operation is undergone through endoscopic passage,for example, endoscopic third ventriculostomy for obstructive hydrocephalus. EAM means the endoscope is used together with microscope. If the surrounding anatomy is complicated or there is dead angle field in microscope, neuroendoscope-assisted technique is useful for observation and deep operation. It combines the advantage of EN and that of microsurgery. Dangerous and complicated operation is done by microscope, while endoscope provides reference for the whole operation. ECM means that the microsurgery procedure is performed with the routine microneurosurgical appliances under the guide of endoscope. In 1971, Wilson firstly advanced the concept of keyhole surgery. He made use of the small incision to treat the intracranial deep lesions. Though the incision and the bony hole are all small, the exposure of intracranial deep structures indicates the effect of"door mirror",which means that the longer distance to the bony hole, the wider exposure of the operation field. In 1978, Bushe, et al firstly reported the application in treating diseases in sellar redion by neuroendoscope. The pterional approach is one of the frequent practical approaches. After stripping sphenoidal crest,the pyramidal space and the natural fissures of the brain will be used to expose anterior cranial fossa,middle cranial fossa, sellar region and upslope. The routine pterional approach is changed into keyhole pterional approach now. In recent years, with the development of microsurgery and the application of neuroendoscope, endoscope-assisted keyhole microsurgery makes a great step. The combination of neuroendoscope and keyhole approach for treating diseases in sellar region is adopted by domestic and overseas scholars, which is the representative of microinvasive neurosurgery. Recently, neuroendoscope-assisted microsurgery used in clipping cranial aneurysm and resection of pituitary adenoma was reported in domestic and overseas literature, but the application of neuroendoscopic technique in the treatment of other sellar area lesions was reported fewer. Objective: To study the utility and advantages of the neuroendoscope-assisted microsurgery for sellar area lesions.Methods: Neuroendoscope-assisted microsurgery was performed on 51 patients with sellar area lesions.Of the total , microsurgery was compared with endoscope-assisted microsurgery in 33 patients with pituitary adenomas.7 cases with intracranial aneurysms(including 1 AcomA aneurysm,5 PcomA aneurysms,1 MCA aneurysm),4 cases with craniopharyngiomas,2 cases with Rathke cysts,2 cases with sellae meningiomas,2 cases with arachnoid cysts in sellar area,1 case with maglinant dysembryoma. A rigid neuroendoscope (0°or 30°) was introduced into the sellar area according to the guildpost. Neurovascular integrity as well as the relationship between tumor and the surrounding structures was evaluated firstly. At the end of the microneurosurgery, neuroendoscope was introduced again so as to verify the optimal clipping position and the total dissection of tumor. If the clipping position was not optimal, readjustment of clipping was performed under microscope or assisted by endoscope. If the residual tumor was found, neuroendoscope-assisted tumor resection was performed.Results: 33 patients with pituitary adenomas were operated with microscope first.20 was total removed, while 13 was subtotal removed. Then, operation combinated with microscope and endoscope was done in the patients of 13 subtotalresection .moreover, 8 was total removed and 5 was subtotal resection(p<0.05). The residual tumor decreases dominantly with endoscope-assisted microsurgery by pterional keyhole approach. It means significant in statistcs. There were no severe postoperative complications and mortality after the neuroendoscope-assisted microsurgery. 2 patients with arachnoid cysts gained satisfactory recovery after endoscope-assisted resection.7 intracranial aneurysms were gained satisfactory clipping and the aneurysm-carrier arteries were not obstructed.2 Rathke cysts were totally removed, so were 2 sellae meningiomas, 2 sellar arachnoid cysts and 1 maglinant dysembryoma.Conclusions: The neuroendoscope-assisted microsurgery for the sellar area lesions is practicable and helpful to increase the microsurgical treatment effect, decrease the operative injury, protect pituitary stalk and reduce the complications via pterional keyhole approach.