Fixed-Volume Gas Fill Technique Following Pars Plana Vitrectomy in Retinal Re-Attachment Surgery

Abstract

Purpose : The commonly used fixed-concentration technique of gas fill, following retinal re-attachment by pars plana vitrectomy (PPV), fluid-air exchange (FAX) and endolaser (EL), involves an approximately 30-50cc lavage with iso-expansile or slightly expansile concentrations of either C3F8 or SF6 gas. This retrospective case series evaluated the efficacy and safety of a gas-sparing fixed-volume technique to achieve extended tamponade.

Methods : Following FAX and EL, trocars were removed and sclerotomies were closed with trans-conjunctival vicryl suture, leaving the retina temporarily under air. Using a 30-gauge needle on a 3cc syringe, 1.0cc of 100% C3F8 or SF6 was injected into the vitreous cavity through the pars plana. Using the same syringe, gas volume was then removed as needed while palpating the globe, ensuring that the eye was left at physiological intraocular pressure (IOP). The main outcome measures included post-operative ocular hypertension (OHTN, defined as IOP>24mmHg) rate, gas bubble duration, anatomical retinal re-attachment rate, and occurrence of endophthalmitis.

Results : The fixed-volume gas fill technique was used on 13 eyes of 13 patients (9 males, 4 females) with an average age of 51 years (range 39-67 years) (Table 1). Ten patients had rhegmatogenous RDs (RRDs), two had diabetic tractional RDs (TRDs) and one had combined diabetic TRD with RRD. Post-operative OHTN rate for C3F8 was 45% (5 out of 11 patients) within the first week (Table 2). Two of these patients had pre-existing glaucoma, one had history of ocular trauma, and two were diabetics. The post-operative OHTN was responsive to medical therapy. Neither of the 2 SF6 patients had post-operative OHTN. The average gas bubble duration for C3F8 was 8 weeks (range 6-12 weeks), and that for SF6 was 2 weeks. Anatomical retinal re-attachment rate was 92% (12 out of 13 patients). There were no cases of post-operative endophthalmitis.

Conclusions : The fixed-volume gas fill technique in this case series had similar post-operative OHTN rates compared to the fixed-concentration technique reported in the literature (6-67% of eyes with SF6, and 18-59% of eyes with C3F8), with similar gas duration and retinal re-attachment rates. The fixed-volume technique may have a few advantages, including gas conservation; and, avoiding hypotony during sclerotomy closure, especially with larger gauge sclerotomies.

This is a 2021 ARVO Annual Meeting abstract.