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J Miller, A Castelo-Branco, P Huie, S Sanislo, MS Blumenkranz, DV Palanker; Application of the Pulsed Electron Avalanche Knife (PEAKTM) to Treatment of Retinal Vascular Occlusions . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1870.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Applicability of the Pulsed Electron Avalanche Knife (PEAKTM) to the treatment of retinal vascular occlusion. Methods: To test applicability of the instrument for sheathectomy, PEAKTM was scanned at various energies along the retinal artery-vein junction of bovine eyes in vitro. Treated tissue was examined by histology and scanning electron microscopy (SEM). PEAKTM energy was also applied to occluded vessels of the chick chorioallantoic membrane in vivo below dissection thresholds. Controlled aneurysms with lumen widening at the site of occlusion were created and examined with morphometry, conventional histology and SEM with and without immunohistochemical staining using Tissue Factor and vonWillebrand Factor. Results: Sheathectomy by vitreoretinal surgeons using PEAKTM was successful at pulse energies between 20 and 50 uJ and a repetition rate of 10 Hz. Aneurysms created by PEAKTM increased luminal diameter 1.5-2 fold, thereby increasing cross-sectional area 2.25-4 fold. Histology demonstrated disruption of the muscular tunics of veins and arteries but little to no damage to endothelium. With appropriately shaped tips, PEAKTM discharges result in pulsed axial forward flow. This was used to push blood columns in excised chick chorioallantoic vessels and may be adapted for mechanical massage and dislodging at an occlusion site. Finally pulsed liquid flow from PEAKTM, in combination with the techniques above, was able to dislodge green argon laser experimentally-induced clots in the chick chorioallantoic vasculature. Conclusion: PEAKTM offers several potential mechanisms for the treatment of retinal venous occlusions. Further studies should permit the optimization of PEAKTM parameters and techniques.
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