Aim : To evaluate the usefulness of the newly designed 25-gauge (25-G) microcannula for transconjunctival sutureless vitrectomy (TSV). Methods : 25-G TSV was performed on 20 consecutive eyes with the newly designed 25-G microcannulas. We studied usefulness, intraoperative and postoperative complications in these cases. 
Results : No complications were recognized during surgery. Postoperative complications included blebs in five eyes, vitreous hemorrhage in one eye, high intraocular pressure (more than 22 mmHg) in one eye and a retinal tear in one eye. No eyes with low intraocular pressure ( less than 10 mmHg) were noted. 
Conclusions : This microcannula for 25-G vitrectomy is thought to be very useful and effective for performing 25-G vitrectomy safely

Naito, Takeshi

Tokushima University Institutional Repository

INTRODUCTIONUse of the 25-gauge (25-G) transconjunctival su-tureless vitrectomy (TSV) system developed by Fujii,et al. (1) has recently been advocated (2, 3). Micro-cannulas for this procedure are thin and the scleralincisions may self-seal without suturing after micro-cannula removal. However, thin and flexible vitreo-retinal instruments have disadvantages, for exam-ple, the thin-walled polyamide microcannulas maybe bent or deformed at the time of insertion, mak-ing insertion difficult (4). An extensive vitrectomyon the retinal periphery is difficult, and slippage orloss of microcannulas can easily occur. This micro-cannula is therefore designed to address the disad-vantages of the polyamide microcannula of the 25-G TSV.METHODSTechniqueThe newly designed microcannula (Duckworth& Kent Inc., Hertfordshire, UK) is made of titaniumand has a step to avoid slippage or loss. The inter-nal diameter of the microcannula is 0.55 mm, theexternal diameter is 0.65 mm, the diameter of thestep is 0.75 mm, and the length is 4.5 mm withoutits head (Fig. 1). The opening of the microcannulais designed for easy insertion of instruments. Iperformed 25-G TSV on 20 eyes of a consecutiveseries of 18 patients with this microcannula. Thesurgical procedure was almost the same as for the23-G vitrectomy reported by Eckardt (5). The con-junctiva was fixed to the sclera with a fixation ring(Duckworth & Kent Inc., Hertfordshire, UK) andORIGINALTransconjunctival sutureless 25-gauge vitrectomy withnewly designed microcannulasTakeshi NaitoDepartment of Ophthalmology and Visual Neuroscience, Institute of Health Biosciences, The Uni-versity of Tokushima Graduate School, Tokushima, JapanAbstract :Aim : To evaluate the usefulness of the newly designed 25-gauge (25-G) microcannula fortransconjunctival sutureless vitrectomy (TSV).Methods : 25-G TSV was performed on 20 consecutive eyes with the newly designed 25-Gmicrocannulas. We studied usefulness, intraoperative and postoperative complicationsin these cases .Results : No complications were recognized during surgery. Postoperative complicationsincluded blebs in five eyes, vitreous hemorrhage in one eye, high intraocular pressure(more than 22 mmHg) in one eye and a retinal tear in one eye. No eyes with low intraocu-lar pressure ( less than 10 mmHg) were noted.Conclusions : This microcannula for 25-G vitrectomy is thought to be very useful and ef-fective for performing 25-G vitrectomy safely. J. Med. Invest. 55 : 51-53, February, 2008Keywords : 25-gauge vitrectomy, transconjunctival sutureless vitrectomy, microcannulaReceived for publication September 10, 2007 ; accepted October25, 2007.Address correspondence and reprint requests to Takeshi Naito,MD, Ph.D., Department of Ophthalmology and Visual Neuro-science, Institute of Health Biosciences, The University ofTokushima Graduate School, Kuramoto-cho, Tokushima 770-8503, Japan and Fax : +81-88-631-4848.The Journal of Medical Investigation Vol. 55 200851the incisions were made by inserting a 25-G microvitreoretinal blade (Bausch & Lomb Inc., Roches-ter, USA) at a 30to 40angle through the conjunc-tiva, sclera, and pars plana 3.5 mm from the cor-neoscleral limbus. The microcannulas were theninserted through the conjunctival incision and intothe scleral tunnel using a cannula inserter (Duck-worth & Kent Inc., Hertfordshire, UK). The can-nula inserter is a blunt instrument holding the mi-crocannula. Vitrectomy was performed throughthree ports using the microcannulas (Fig. 2). In thecases which combined lens surgery with the 25-Gvitrectomy, phacoemulsification with intraocular lensimplantation was performed. All incisions self-sealedwithout suturing. We studied intraoperative and post-operative complications of these cases.PatientsInformed consents were obtained from all pa-tients before surgery.25-G TSV was performed on 20 consecutive eyes.The indications for vitrectomy were : proliferativediabetic retinopathy in nine eyes, epiretinal mem-brane in six eyes and macular hole in five eyes. In11 eyes, vitrectomy was combined with phacoemul-sification and implantation of a posterior chamberintraocular lens. In these cases, the three cannulaswere emplaced before phacoemulcification. Foureyes were already pseudophakic. Six eyes receivedgas tamponade and four eyes received air tampon-ade at the end of the surgery. The microcannulaswere simply removed from the scleral tunnels andthe conjunctiva was pushed laterally using a cotton-wool applicator to separate its incision from thescleral incision. A mixture of antibiotic and corti-costeroid was injected into the subconjunctival space.The patients were examined daily for the first 5 daysafter surgery and at 2 weekly intervals thereafter.The follow-up period lasted more than 3 months.RESULTS25-G TSV was performed on 20 eyes with thenewly designed microcannulas without any prob-lems. No operations were converted to conventional20-G vitrectomy. Peripheral vitrectomy with scleralindentation could be performed the same way as a20-G vitrectomy. Intraocular laser photocoagula-tion to the peripheral retina was performed withoutany problems. The microcannulas were stable, with-out slippage or loss during the insertion and re-moval of instruments, or the peripheral vitrectomyand peripheral laser photocoagulation. No compli-cations were recognized during surgery. Postop-erative complications included blebs in five eyes,vitreous hemorrhage in one eye, high intraocularpressure (more than 22 mmHg) in one eye and aretinal tear in one eye. No eyes with low intraocu-lar pressure (less than 10 mmHg) were noted.DISCUSSIONUse of the 25-G TSV developed by Fujii, et al. (1)has recently been advocated (2, 3). The most impor-tant advantage of this procedure is the self-sealingwithout suturing after removal of the microcannu-a bFig. 1. a The newly designed microcannula is made of tita-nium and has a step to avoid slippage or loss.b The opening of the microcannula is designed for easy inser-tion of instruments.a bc dFig. 2. a The conjunctiva was fixed to the sclera with a fixa-tion ring and the incisions were made by inserting a 25-Gmicro vitreoretinal blade at a 30to 40angle through the con-junctiva, sclera, and pars plana 3.5 mm from the corneosclerallimbus.b The microcannulas were inserted through the conjunctivalincision and into the scleral tunnel using a cannula inserter.c, d Vitrectomy was performed through three ports using themicrocannulas.T. Naito Newly designed 25-G microcannula52las. Some disadvantages have however been recog-nized when it is compared to the 20-G system (4),the main ones being thin and flexible instruments,difficulty with peripheral vitrectomy, slippage orloss of the microcannula, and reduced efficiency ofvitrectomy. The 23-G TSV was developed by Eckardtto address these disadvantages (5), and was thoughtto be a transitional system until the 25-G TSV wasimproved. The newly designed microcannula wasmade of metal to address the disadvantages of the25-G TSV using the polyamide microcannula. Themetal microcannula seemed to be less flexible thanthe polyamide microcannula. The step of the mi-crocannula was quite effective in preventing slippageor loss. The insertion and removal of instrumentsthrough the microcannula, peripheral vitrectomyand intraocular laser photocoagulation with inden-tation of the sclera were performed safely withoutany problems. The scleral incisions self-sealed with-out suturing after removal of the microcannulas inall cases. Surgical procedures were performed thesame way as with the 20-G system without any se-rious complications. Notably, there were few com-plications during surgery. The reason is thoughtto be that there is no incarceration of the vitreousduring surgery. With the 20-G system, incarcera-tion of the vitreous into the incisions sometimescauses peripheral retinal breaks during the inser-tion or removal of instruments. In the 25-G system,the insertion or removal of instruments through themicrocannula can prevent the occurrence of pe-ripheral retinal breaks. In this case series, retinalbreak formation was recognized postoperatively. Itis not clear if the retinal break formation is an in-traoperative complication or due to contraction ofthe residual vitreous postoperatively. This retinalbreak was well managed with a gas injection andlaser photocoagulation without further vitrectomy.This new microcannula is thought to be very use-ful, effective and safe for 25-G vitrectomy.REFERENCES1. Fujii GY, de Juan E Jr, Humayum MS,Pieramici DJ, Chang TS, NgE, Barnes A, WuSL, Sommerville DN : A new 25-gauge instru-ment system for transconjunctival suturelessvityrectomy surgery. Ophthalmology 109 : 1807-1813, 20022. Lakhanpal RR, Humayun MS, de Juan E Jr,Lim JI, Chong LP, Chang TS, Javaheri M, FujiiGY, Barnes AC, Alexandrou TJ : Outcomes of140 consecutive cases of 25-gauge transcon-junctival surgery for posterior segment dis-ease. Ophthalmology 112 : 817-824, 20053. Ibarra MS, Hermel M, Prenner JL, Hassan TS :Longer-term outcomes of transconjunctival su-tureless 25-gauge vitrectomy. Am J Ophthalmol139 : 831-836, 20054. Byeon SH, Chu YK, Lee SC, Koh HJ, Kim SS,Kwon OW : Problems associated with the 25-gauge transconjunctival sutureless vitrectomysystem during and after surgery. Ophthal-mologica 220 : 259-265, 20065. Eckardt K : Transconjunctival sutureless 23-gauge vitrectomy. Retina 25 : 208-211, 2005The Journal of Medical Investigation Vol. 55 February 2008 53

Transconjunctival sutureless 25-gauge vitrectomy with newly designed microcannulas

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Transconjunctival sutureless 25-gauge vitrectomy with newly designed microcannulas

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