Endoscopic Transglabella Keyhole Approach:Anatomic Study

Objective: Use of enlarged superiority of endoscopic,to study the endoscopic anatomy of the anterior skull base and saddle area via the glabella keyhole approach and discuss the feasibility and indications of this approach.Materials and Methods: Craniotomy procedures performed via the midsagittal line endoscopic trans glabella keyhole approach were simulated on ten adult cadaveric heads fixed by formalin.And the related anatomical structures in the anterior skull base and saddle area were observed through the 0° endoscope or 30° one.1cm on the nasal root for horizontal scalp incision.And along the eyebrows on both sides of the extension.Both ends of the supraorbital Orbital notch as the boundary,was open "U" shape,about 4.5-5.0cm in length.In the bone tissue and Intracranial anatomy,the complete simulation of the operation.Separation of the skin to the eyebrow arch,and in the nasal septum 10 mm midway between the formation of about 30 × 25 mm bone window,observe the relationship with the frontal sinus,ligation of the sagittal sinus at the base near the skull,cut the dural.And gradually separated the longitudinal and forehead,deep cranial anatomy.Respectively into the 0 ° and 30 ° endoscopy to observe the scope of endoscopic observation within a limited range of endoscopic bone,endoscopic operating space,endoscopic endoscopic and vascular adjacent to each other,the saddle area structure of the mutual relationship.And measure the interproximal keyhole approach bone window distance from the anterior skull base and saddle area of the length of the structure and other anatomical data.Observe the scope of the operation of the exposed area and measure the relevant anatomical parameters and do analysis.Clear surgical indications and feasibility in order to provide the basis for clinical application.Results: Under the endoscopic observation,the exposed area in the bone window was 1 cm above the root of the nose for horizontal scalp incision and extended to both sides along the eyebrows,about 5.0cm in length.And in the nasal septum 10 mm in the middle of the glabella to form a bone window of about 30 ×25mm size observed in the process.1.Anatomically-oriented anatomical structures include anatomic landmarks such as sieve plate,olfactory groove,olfactory bulb,olfactory tract,sphenoid platform,saddle nodule,anterior bed protrusion,posterior bed protrusion,septum,Optic nerve,optic tract,internal carotid artery,posterior communicating artery,anterior choroidal artery,anterior cerebral artery,anterior communicating artery,medial middle cerebral artery,medial temporal lobe,parahippocampal gyrus,oculomotor nerve,pituitary stalk,anterior commissure.Even the third ventricle,midbrain aqueducts and other organizational structures can be observed.Endoscopic anterior skull base can be bilateral neural vascular tissue structure can provide adequate exposure.2.The results showed that the distance from the lower border of bone window to the left anterior prominence was(61.97 ± 3.51)mm,the distance to the right anterior prominence was(62.21 ± 3.20)mm,the distance from the midpoint of anterior optic chiasm was(67.40 ± 5.38)mm,and the distance to the center of saddle nodule was(57.91 ± 2.64)mm,and the distance to the center of saddle was(68.45 ± 4.88)mm,and the distance to the midpoint of endplate was(67.86 ± 4.91)mm,the artery distance was(60.89 ± 6.17)mm,the distance to the left posterior approach was(67.56 ± 3.84)mm,the distance to the right posterior approach was(66.78 ± 3.23)mm,and the left internal carotid artery bifurcation(69.45 ± 2.34)mm,and the distance to the right carotid bifurcation was(68.01 ± 3.53)mm.Conclusion: A wide surgical area including the anterior cranial fossa and saddle area was exposed via the glabella keyhole approach by using neuroendoscope.In the glabella keyhole approach can better reveal the anterior skull base on both sides and saddle area near the midline anatomy.It can be revealed to the resection of lesions of middle anterior skull base,such as olfactory groove meningioma,sphenoid platform meningioma and so on.This approach can provide a good exposure to the suprachiasmatic space for tumors in the midline of the suprasellar region as well as tumors grown to the saddle and can be used for clipping the basilar artery aneurysm and the anterior communicating aneurysm,even the retroperitoneal aneurysms.And in this keyhole approach under the neuroendoscopecan also have a fairly expose for the three ventricle structure.Compared with the microscope,neuroendoscope has many benefits,such as with good lighting,close to the observation,a broader field of vision.The endoscopic probe is so slender that it can through a narrow gap to reach deeper lesions.It can not only increases the security and accuracy of the operation to a certain degree,but also extends surgery indications to some extent.However,there is also a risk of concurrent infection and cerebrospinal fluid leakage and is not recommended for patients with brain swelling.