Sir,

Antimetabolite augmented trabeculectomy is now commonplace1. The recent evolution of trabeculectomy technique and adoption of Mitomycin C and 5-Fluorouracil has caused no significant safety implications, despite early fears.2

We wish to share an additional technique to improve safety after suffering the unfortunate scenario of misplacing a mitomycin-soaked pledget during trabeculectomy. Meticulous surgical technique, a conscientious scrub nurse and methods of tracking sponges/pledgets (counts, receiver pads, radio-opaque materials) should all ensure that loss of surgical material is rare. However, retained surgical sponges are common enough to deserve descriptive terminology; Gossypiboma, derived from the Latin ‘gossypium’ (cotton) and the Swahili ‘boma’ (place of concealment). There are three case reports in ophthalmic literature of retained material causing granulomatous bleb reactions/blebitis thereby increasing the risk of bleb-related endophthalmitis.3, 4 The true incidence of retained material following glaucoma surgery is unknown and probably much underreported.

The quest for better aqueous flow drives the insertion of pledgets as posteriorly as possible under the conjunctiva. Our pledget was eventually located but the guddle fuelled refinement to our standard technique.

We use polyvinyl alcohol (PVA) after evidence suggesting cellulose can be friable and shed microscopic filaments.5 A PVA wick is cut by hand to create pledgets which are ‘strung’ onto a 5/0 black silk suture (MersilkTM code W500). The resulting ‘necklace’ is then used without the need to deviate from usual antimetabolite application technique. To remove, the necklace suture is gently eased out. The remaining PVA wick is cut to a 20 mm length, which is soaked in Pilocarpine 2% and used as a corneal light shield providing additional miosis. To date (48 cases) we have zero incidence of the suture cheesewiring through the pledgets nor does the suture cause any additional snagging of sponges on removal Figure 1.

Figure 1
figure 1

(a) Instruments required including 5/0 Mersilk suture (code W500) and PVA wick. (b) PVA wick cut into pledgets. (c) Pledgets strung onto suture. Placing suture so 1/3rd of pledget above and 2/3rd below facilitates smoother subconjunctival sponge insertion. (d) Pledgets separated to approximately 6 cm to improve insertion.

Full size image

To summarise, the use of a ‘necklace’ suture prevents inadvertent pledget loss during trabeculectomy, a rare but significant cause of bleb-related inflammation.