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R. Shah, R.D. Robinson, J.H. Shen, M.R. Feurtado, K.M. Joos; Endoscopic–Approach Development for Minimally Invasive Orbital Surgery . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5074.
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© ARVO (1962-2015); The Authors (2016-present)
Orbital tumors and pseudotumor cerebri are sometimes treated with orbital surgical approaches. Our previous studies suggest that potentially endoscopy may be useful for minimally invasive orbital therapy. This study proposed to improve a technique for accessing the posterior orbital space via endoscopy with the application of Free Electron Laser (FEL) energy, biopsy forceps, vessel coagulation, and CO2 insufflation to posterior orbital tissues.
An inferior transconjunctival approach was used to access the posterior orbital space in 14 eyes of 7 non–survival pigs. A guidance tube and the endoscope monitor were used to guide the surgeon to the posterior orbit. Then FEL energy application (6.1 µm, 2.7 ± 0.5 mJ, 30 Hz, delivered via a glass–hollow waveguide), tissue excision with biopsy forceps, and monopolar electrocautery were attempted via endoscopy. The effects of CO2 gas insufflation were then assessed by analyzing arterial blood gases for 3 consecutive 30–minute intervals.
The posterior orbit was accessed via endoscopy in all except the first attempted eye. Additionally, the optic nerve was encountered and FEL energy was applied in 8 of the 14 trials. Applications of biopsy forceps to the incised optic nerve sheaths and electrocautery to vessels were successful and documented by histology. Although ANOVA statistical tests for arterial blood gas changes were insignificant: pH % change=0.936% (P=0.93), pCO2 % change=13.7% (P=0.82), HCO3– % change=7.41% (P=0.39); visibility was adequate without CO2 insufflation.
The posterior orbit was successfully accessed using endoscopy. The optic nerve was also exposed and successfully treated with FEL energy, which was not an original objective. CO2 insufflation did not alter blood gases, but did not further enhance visibility in this study. Application of endoscopy for posterior orbital procedures is feasible, but extreme surgical care is required and further study with human cadaveric eyes is needed.
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