Minimally invasive techniques have been introduced across virtually the whole spectrum of surgery. In ophthalmology sutureless operating techniques in cataract surgery and recently in vitrectomy offer less postoperative inflammation, shorter intraoperative and recovery time. In this article is reported the evaluation, feasibility and safety of the Sutureless Transconjuctival 20 Gauge Vitrectomy (20 STV).

This is a retrospective, non randomized study and 622 eyes underwent this new technique between April 2006 and November 2008. Cases from almost all the spectrum of vitreoretinal surgery were operated in this way. These included patients with epiretinal membrane, macular hole, diabetic vitreous haemorrhage with or without traction retinal detachment, phakic or pseudophakic retinal detachment including those with proliferative vitreoretinopathy, and dropped nucleus.

How the technique works

Figure 1: The technique begins with diathermy of the conjunctiva (1a) with a 'short neck' wide tip diathermy probe (1b-arrow).

The technique begins with diathermy of the conjunctiva (Figure 1a) using a 'short neck' wide tip diathermy probe (Figure 1b) over the areas of the side ports. The diathermy has to be broad and intense. The probe presses and stretches the conjunctiva over the sclera. The conjunctiva becomes thin or very thin and some times creates an opening with gradually thinning rim that is sealed with the underlying sclera. The visible end point of the conjunctival burn is a white circle the size of which must be large enough (4-5 mm diameter) (Figure 2). This is an extremely important point of the technique. Adequate diathermy is convenient for introducing the instruments, especially at the very beginning. A preferable end point is the creation of a very thin layer of the conjunctiva or even better the opening of it with a gradually thinning rim that is sealed with the underlined sclera. This provides easier access to scleral tunnels. The adhesion between conjunctiva and sclera also prevents intraoperative bleeding and inflation of the subconjunctival space with infusion fluid.

Figure 2: The infusion canula is an Anterior Chamber Maintainer (2a). White large diathermy scars are located at the side ports areas. The entering site of the superotemporal tunnel is indicated with the arrows. A MVR blade with a bevelled direction is been introducing in to the conjunctiva-sclera (2b).

A 20G MVR blade is used in a bevelled almost tangential way to create a combined conjunctivo-scleral tunnel incision in the inferotemporal quadrant. The blade is directed vertically just before entering the vitreous cavity to create a better wound sealing at the end of the operation. An anterior chamber maintainer is used in this port without a suture (Figure 2a).

Figure 3: Taking the instruments slowly out of the tunnels will prevent the vitreous incarceration in to the wounds. Immediate massage over the tunnels assists them to close firmly.

Superotemporal and superonasal conjunctivo-sclerostomies are then made (Figure 2 inset). The light pipe and the vitrector as well as other instruments (such as micro forceps, micro scissors and Phacopfragmentor) are easily introduced through these incisions. Difficulty in introducing the instruments initially through the tunnels is minimal.

Figure 4: At the end of the operation the incisions are tightly closed. The intraocular pressure is normal.

At the end of the operation intraocular pressure will be normalised (from 30 mmHg that is during the operation) due to a minimal leak during the closure of the tunnels. Taking the instruments slowly out of the tunnels will prevent the vitreous incarceration in to the wounds. Immediately massaging with a cotton tip over the port will allow the scleral flaps of the tunnel to expand (they are mildly shrinked due to manoeuvres of the instruments) and collapse one over the other (Figure 3). That will stop the entry port leak.

Subconjunctival antibiotics and corticosteroids are used at the end of the procedure. Few fluid filled eyes had minimal leakage of fluid. Eyes with air or gas fill are less likely to be hypotonous at the end of theoperation. Eyes that ended up with silicone oil had no leakage at all due to higher viscosity of the oil. The pressure of the eyes at the end of the operation was either normal or slightly low. In cases where hypotony was noticed additional air or fluid was injected through pars plana with a 27 gauge needle. Slight chemosis occurred in a few cases.