The soft-tipped extrusion cannula is commonly used during vitrectomy in complex retinal detachments for internal drainage of subretinal fluid. The soft tip consists of a silicone sleeve. We report a case with an unusual complication: the silicone sleeve of a soft-tipped extrusion cannula was accidentally left behind following a vitrectomy procedure.
A 20-year-old male sustained a perforating injury to his right eye with a wooden stick. He was seen at our facility following primary repair of the injury elsewhere 15 days earlier. The right eye vision was light perception. A 10 mm long sutured radial scleral wound was present at 2 o’clock, extending posteriorly from the limbus. The cornea was clear, sector iridectomy was present at the wound site and the eye was aphakic. There was no fundus view due to total vitreous haemorrhage. The eye was soft and the intraocular pressure was 2 mm Hg. B-scan ultrasonography showed total retinal detachment. He underwent a combined vitreo-retinal procedure consisting of encircling band, pars plana vitrectomy, fluid-air exchange, transvitreal and subretinal fluid drainage with soft-tipped extrusion cannula on a fluted handle, endophotocoagulation around the retinal break, inferior basal iridectomy and silicone oil injection (1000 centistokes). The soft-tipped extrusion cannula was a 12 mm long 23-gauge silicone sleeve fitted over a tapered metal tip of a 20-gauge extrusion cannula. This was introduced through a 20-gauge sclerotomy site to drain the subretinal fluid internally. Surgery was uneventful and the retina settled although macula was badly scarred. On the first postoperative day, the retina was attached. The silicone sleeve of the soft-tipped extrusion cannula was seen lying on the lower buckle-indented retinal surface (Figure). Visual acuity was counting fingers at Z\c metre. On checking the instruments that were used for surgery, the silicone sleeve of extrusion cannula was found missing. This information was kept from the patient since silicone oil had to be removed later and it was planned that the silicone sleeve would be removed along with silicone oil at the 2-month follow-up. But the patient was not willing to return in 2 months’ time. Finally, a year later, the silicone sleeve was removed along with the silicone oil. The silicone sleeve was held with intraocular forceps and easily removed. During the one year period, the eye had remained quiet, IOP remained at 15 mm Hg and the vision was stable. The silicone sleeve had lain mobile in the lower vitreous cavity over the retina and did not cause any apparent mechanical problem or toxicity.
Since first described by Flynn et al, the soft-tipped extrusion cannula has been commonly used to drain the posterior subretinal fluid. The flexible silicone tubing attached to the end of a tapered extrusion needle is advanced into the subretinal space through an open peripheral break to allow drainage of posterior subretinal fluid atraumatically. Internal drainage of subretinal fluid is accomplished by allowing its egress out of the eye as air fills the vitreous cavity through the infusion cannula. We present this unusual case in which the silicone sleeve of soft-tipped extrusion cannula was left inadvertently inside the eye after vitrectomy. While withdrawing the soft-tipped extrusion cannula from the eye following internal drainage of transvitreal and subretinal fluid, probably the loose silicone sleeve got entangled at the inner lip of the sclerotomy/vitrectomy port and finally fell on the lower peripheral retina. This was discovered only later. It lay in the eye for one year without causing any problem.
In our experience, the loose silicone sleeve of the soft-tipped extrusion cannula does occasionally get entangled in the sclerotomy site but it is usually discovered immediately and easily removed. A retained intraocular sleeve has not been reported earlier. It is important to check the integrity of the silicone sleeve before and after completion of surgery. The nurse should also be instructed to check the cannula following its use.
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1. Flynn HW Jr, Blumenkranz MS, Parel JM, Lee WG. Cannulated subretinal fluid aspirator for vitreoretinal microsurgery Am J Ophthalmol. 1987;103:106–8
2. Flynn HW Jr, Lee WG, Parel JM. A simple extrusion needle with flexible cannula tip for vitreoretinal microsurgery Am J Ophthalmol. 1988;105:215–16