ABSTRACT
Objective To explore the formation mechanism of peritumoral brain edema(PTBE)by vascular endothelial growth factor(VEGF).Methods 40 biopsies were obtained from 37 patients.Inmunohistochemical staining and Western blot were performed to detect the expression of VEGF protein.Reverse-transcriptase polymerase chain reaction(RT-PCR)was used to analyze the presence and quantity of VEGF mRNA.The extent of PTBE was estimated as an edema index(EI)based on preoperative magnetic resonance imaging.Results In VEGF-positive cases,a decreasing gradient of VEGF protein expression was observed with increasing distance from tumors(0.38±0.08,0.20±0.03,0.04±0.02).In meningiomas,the protein level and the mRNA level were congruent and the expression of both protein and mRNA had a significant correlation with EI(protein: r =0.892,RNA: r =0.875,P ＜ 0.05).However,in peritumoral areas,protein level were not consistent with the mRNA level.Protein results showed high correlation with EI(r =0.912,P ＜ 0.05),but mRNA almost was almost undetectable(0.06±0.02).Conclusion VEGF is impartant on PTBE.It is concluded that VEGF macromolecules are secreted by tumor tissue and enter peritumoral normal brain tissue to induce edemagenesis in meningiomas.
ABSTRACT
Objective To compraison the of exposure in the endonasal transsphenoidal approach to the sellar between microscope and endoscope. Methods Ten formalin-fixed, silicone-injected adult cadveric heads were studied. A direct endonasal transsphenoidal approach was performed via the right nostril, pushing aside the nasal septum, then reach the sphenoidal sinus. The approach was performed with the operating microscope first, then with the endoscope. For each step (sellar, suprasellar, parasellar and clival), the operative region afforded by direct microscopic view was measured and then compared with that obtained by using the edndoscope. Results It was found that the endoscope provided greater view than microscope in this approach. Although the microscope provides an adequate view of the midline structures and part of the contralateral parasellar areas; under direct endoscopic vision, the lateral extension could be widened by an additional 6.5 mm on the ipsilateral and 4 mm on the contralateral side. At suprasellar region, the microscope provides could expose the posterior part of, optic nerve and optic chiasma; but could not expose the areas anterior and superior the interspace superior the optic chiasma. Compare with the microscope, the endoscope allowed extension of bone removal and dual opening for an additional 4 mm anteriorly at the sagittal axis and an additional 3.5 mm on the ipsilateral and 4 mm on the contralateral side. At the clivus region, the medial surface of the vertical segment of the ICA and the basilar artery could be partially 7 exposed by the microscope. By the endoscope, it could gain an additional 4 mm on the ipsilateral side and 2.5 mm on the contralateral side in width. Because of the anatomical boundaries of the sphenoid sinus, the anatomincal exposure by the microscope same as the endocope at the sagittal axis. Conclusion The endoscope allows for a panoramic view and permits widening of the operative exposure in all directions. The endoscope is more suitable in the the minimal and expanded endonasal transsphenoial approach.