Kiliç, Emine

Manning, S

van Overdam, KA

Verdijk, Rob

English

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Intra-ocular diathermy forcepsKoen A. van Overdam,1,2 Emine Kilic,3 Robert M. Verdijk1,4 and Sonia Manning11Department of Vitreoretinal Surgery, The Rotterdam Eye Hospital, Rotterdam, the Netherlands2The Rotterdam Ophthalmic Institute, Rotterdam, the Netherlands3Department of Ophthalmology, Erasmus MC University Medical Center, Rotterdam, the Netherlands4Department of Pathology, Section Ophthalmic Pathology, Erasmus MC University Medical Center, Rotterdam, the NetherlandsABSTRACT.Purpose: The purpose of this study was to develop intra-ocular diathermyforceps and test them on perfused porcine cadaver eyes.Methods: We designed two types of 23-gauge intra-ocular bipolar diathermyforceps by modifying commercially available membrane peeling forceps. In thefirst type, the emitting electrode is connected to one-half of the core and thereturn electrode to the other half, with one jaw of the forceps attached to eachhalf. In the second type, the emitting electrode is attached to the core and bothjaws of the forceps, and the return electrode to the surrounding tube. Wecompared the new diathermy forceps to conventional intra-ocular diathermy, onperfused porcine cadaver eyes. First-order retinal artery and vein closure wasconfirmed both by a perfusion study and by histology of the treated vessels.Results: Type 1 diathermy forceps closed retinal arteries and veins moresuccessfully (five of five and five of five successful treatments, respectively) thanType 2 diathermy forceps (five of five and four of five, respectively) andconventional diathermy (three of five and four of five, respectively). Less energywas used with Type 1 compared to Type 2 and conventional for artery closure(1.5  0.0 versus 4.6  3.3 versus 2.1  0.8 joules, respectively) and veinclosure (1.5  0.0 versus 5.4  4.6 versus 2.4  0.8 joules, respectively).Histology of the treated vessels confirmed the perfusion study results.Conclusion: We designed two types of a new multifunctional intra-ocularinstrument with the ability to peel membranes and to grasp, compress andcoagulate retinal blood vessels. Both types pose operational advantagescompared to current conventional intra-ocular diathermy.Key words: coagulation – intra-ocular diathermy forceps – perfusion – porcine eye model – reti-nal blood vessels – retinal hemangioblastomaActa Ophthalmol.© 2017 The Authors. Acta Ophthalmologica published by John Wiley & Sons Ltd on behalf of Acta OphthalmologicaScandinavica Foundation.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, whichpermits use, distribution and reproduction in any medium, provided the original work is properly cited and is not usedfor commercial purposes.doi: 10.1111/aos.13619IntroductionIntra-ocular diathermy was pioneeredin the 1970s (Parel et al. 1974).Monopolar diathermy coagulatedblood vessels, but caused collateralretinal damage. Bipolar diathermyhad narrower coagulation boundaries(Tate et al. 1975; Parel et al. 1983).There have been no advances in intra-ocular diathermy design since the1980s, in contrast to laparoscopicsurgery, where bipolar diathermy for-ceps are routinely used since the 1990s(Entezari et al. 2007).Current bipolar intra-ocular dia-thermy probes have multiple weak-nesses, which become evident duringattempted closure of hemangioblas-toma feeder vessels (van Overdamet al. 2017). The conventional dia-thermy probe is point-shaped. Thesurgeon must push on the blood vesselwith the probe to close it and thencoagulate it. High energy levels areneeded to coagulate the distal vesselwall, leading to collateral damage.Secondly, the tip of the diathermy probeblocks the surgeon’s view of the bloodvessel and coagulation reaction, unlessthe surgeon removes the probe from thetreated area. Thirdly, in case of iatro-genic bleeding, there is unavoidabledelay between the removal of theinstrument involved in the bleedingepisode and the introduction of thediathermy probe into the eye. Thismakes bleedingmore difficult to control.Therefore, we designed a new intra-ocular instrument combining the abil-ity to apply mechanical compressionfrom opposite sides, a diathermy func-tion and a membrane peeling function,which addresses these weaknesses.Materials and MethodsTwo types of bipolar diathermy forcepswere developed by modifying availablesingle-use 23-gauge peeling forceps(Vitreq, the Netherlands; Bausch &Lomb, US). In Type 1, the emittingelectrode is connected to one-half ofthe core and the return electrode to theother half, with one jaw of the forcepsattached to each half of the core. In1Acta Ophthalmologica 2017Type 2, the emitting electrode isattached to the core and both jaws ofthe forceps and the return electrode tothe surrounding tube. Both types retainmembrane peeling function.The diathermy forceps were testedex vivo on perfused porcine cadavereyes. The eyes were harvested at a localabattoir immediately after killing theanimal and transported in heparinizedsaline (50 units/ml), in melting ice. Thetime between eye harvesting and prepa-ration was less than 6 hr.The ophthalmic artery was cannu-lated with a 23-gauge cannula. Theretinal vessels were accessed via anopen-sky approach. The vitreous wassegmented with No 05-0740 scissors(Lawton, Germany) and was removed,as much as possible, from the retinalsurface, with cotton buds. The eyeswere filled with perfluorodecalin(DORC, Netherlands). A bloodcolumn was present in the retinalvessels at the end of the process.We powered the diathermy instru-ments with a bipolar coagulator(450 kHz) (Aesculap, Germany), deliv-ering power in 0.1 watt steps. Thesurgeon adjusted energy duration byfoot pedal. A starting power of 1.5 wattwas chosen based on published recom-mendations (Parel et al. 1983).Fifteen porcine eyes were used, fivewith Type 1, five with Type 2 and fivewith a conventional disposable23-gauge bipolar diathermy (KirwanSurgical Products, US). We treated afirst-order branch of the superior orinferior retinal artery and vein, byeither compressing the vessel lumenfrom both sides with the diathermyforceps or by pushing from above withconventional diathermy, until we sawcomplete disruption of the blood col-umn, caused by coagulation. Weconfirmed the results of the coagula-tion treatment by perfusing the eyeswith 100 ml heparinized (50 IU/ml)succinylated gelatin 4% (B.Braun, Ger-many) with 30 mg of fluorescein addedto it, at 0.1 ml/min, using a micropro-cessor-controlled dispensing pump(ALT, US).The eyes underwent standard for-malin fixation and paraffin embeddingprior to histological examination.ResultsThe results of the perfusion study andthe energy required to close retinalarteries and veins with conventional,Type 1 and Type 2 diathermy forceps,are given in Table 1.Two coagulation applications wereneeded with conventional diathermy intwo of five eyes (arteries) and three offive eyes (veins) because the studyTable 1. Ex vivo performance of the diathermy forceps compared to conventional diathermy.Diathermy Type Eyes (n)Closure rate Energy (joules  SD) Time (seconds  SD)Artery Vein Artery Vein Artery VeinConventional diathermy probe 5 3/5 4/5 2.1  0.8 2.4  0.8 1.4  0.5 1.6  0.5Type 1 diathermy forceps 5 5/5 5/5 1.5  0.0 1.5  0.0 1.0  0.0 1.0  0.0Type 2 diathermy forceps 5 5/5 4/5 4.6  3.3 5.4  4.6 1.2  0.8 1.4  1.1SD = standard deviation.(A) (B) (C)v v va aaaaavvvFig. 1. Fundus photographs and histology slides of coagulated porcine retinal blood vessels. Histology slides (above) and fundus photographs(below) of porcine retinal arteries (labelled a) and veins (labelled v) coagulated with conventional diathermy (panel A), Type 1 diathermy forceps(panel B) and Type 2 diathermy forceps (panel C). In the fundal photographs, the blood columns in the artery and vein have been interrupted bycoagulation. The coagulated site and the blood vessel downstream from it show no flow during perfusion of the ophthalmic artery with fluorescein-stained fluid. The histology slides (magnification 100x; haematoxylin and eosin stain) show coagulated and closed retinal blood vessels followingapplication of diathermy. Retinal detachment is a common artefact because of preparation of the eye for the perfusion study and/or tissue processingfor histological examination.2Acta Ophthalmologica 2017investigator did not see sufficient coag-ulation reaction after the first applica-tion.For Type 2 forceps, the startingpower was increased to 4.0 wattbecause there was no diathermy effectwith lower power in the first two eyes.More vitreous was removed from theretinal surface in the remaining threeeyes, which reduced the power neededto close the vessels. Use of Type 2diathermy forceps can be seen in theVideo Clip S1.Histology of the treated vessels con-firmed the results of the perfusionstudy. Both types of forceps closedretinal arteries and veins more effec-tively than conventional diathermy.Fundus photographs and histologyslides of coagulated porcine retinalblood vessels, coagulated with conven-tional, Type 1 and Type 2 diathermyforceps, are shown in Figure 1.CommentThis is the first report on two types of anew intra-ocular bipolar diathermyinstrument, since the publication byParel et al. (1983) on the conventionalbipolar diathermy probe. Both types,in an ex vivo proof-of-concept study,grasp, compress and coagulate retinalblood vessels more effectively thanconventional diathermy.Our design successfully addressesweaknesses of conventional diathermy.Firstly, the blood vessel can be com-pressed between the jaws of the forcepsand be coagulated using lower energy.Secondly, the design ensures visualiza-tion of the target blood vessel duringthe entire coagulation process so theminimum energy necessary is used. Theex vivo nature of the model allows forenergy requirement comparisonbetween the diathermy forceps andconventional diathermy. The compar-ison favours the diathermy forceps.Thirdly, the diathermy forceps can beused as regular micro-forceps, withdiathermy continuously available fortissues that are being manipulated andat risk of sudden bleeding.The presence of vitreous close toblood vessels increased the energyrequirements for coagulation whenusing Type 2 forceps. This may bebecause the space between the emittingand return electrodes (the jaws and thetube of the forceps) can be occupied byvitreous, which interferes, due to itshigher impedance than water, with theelectric current. In contrast, in Type 1forceps, the emitting and return elec-trodes are connected to the jaws of theforceps with the target blood vessel,but no vitreous, directly between them.We have designed a new intra-ocularinstrument combining the ability toapply mechanical compression on oppo-site walls of a blood vessel, with abipolar diathermy and membrane peel-ing function. This enables the surgeonto have, in effect, multiple instruments,including more effective diathermy, inone hand, meaning that there is nodelay between onset of bleeding andcoagulation. This will facilitate intra-ocular vascular control.ReferencesEntezari K, Hoffmann P, Goris M, Peltier A &van Velthoven R (2007): A review of cur-rently available vessel sealing systems.Minim Invasive Ther Allied Technol 16:52–57.van Overdam KA, Missotten T, Kilic E &Spielberg LH (2017): Early surgical treat-ment of retinal hemangioblastomas. ActaOphthalmol 95: 97–102.Parel JM, Machemer R & Aumayr W (1974):A new concept for vitreous surgery. 4.Improvements in instrumentation and illu-mination. Am J Ophthalmol 77: 6–12.Parel JM, Machemer R, O’Grady GE, CrockGW & Nose I (1983): Intraocular diathermycoagulation. Graefes Arch Clin Exp Oph-thalmol 221: 31–34.Tate GW JR, Hutton WL, Vaiser A & SnyderWB (1975): A coaxial electrode for intraoc-ular diathermy. Am J Ophthalmol 79: 691–693.Received on March 16th, 2017.Accepted on September 5th, 2017.Correspondence:Koen A. van Overdam, MDThe Rotterdam Eye HospitalSchiedamse Vest 1803011 BH RotterdamThe NetherlandsTel: +31 (0)10 401 77 77Fax: +31 (0)10 401 77 55Email K.vanOverdam@oogziekenhuis.nlKoen van Overdam and Sonia Manning hadfull access to all the data in the study and takeresponsibility for the integrity of the data andthe accuracy of the data analysis. In addition,the authors would like to acknowledge theinvaluable contribution of Piet Hoogenboomof the Rotterdam Ophthalmic Institute,involved in the development of the ex vivoporcine perfusion model and Rene Geleijnseof Create-Technology.nl, involved in thedesign and manufacture of the diathermyforceps prototypes. The Scientific ResearchFoundation of the Rotterdam Eye Hospital(SWOO-Flieringa Foundation) funded theex vivo porcine perfusion study and theprocessing of the histology speciments.Supporting InformationAdditional Supporting Informationmay be found in the online version ofthis article:Video Clip S1. Use of the diathermyforceps on a porcine retinal vein andartery. Subsequent perfusion of theophthalmic artery with fluorescein-stained infusate shows that the coagu-lated sites and the blood vessels,downstream from those sites, show noflow.3Acta Ophthalmologica 2017

Intra-ocular diathermy forceps

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Intra-ocular diathermy forceps

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