Pneumatic Trabeculectomy: A Modification in Conventional Trabeculectomy

We developed a novel technique called "pneumatic trabeculectomy"(PTB) which uses constant pressure air infusion via the Constellation Vision System (Alcon. Laboratories, Inc., Fort Worth, TX, USA) system to prevent anterior chamber collapse/intraocular pressure fluctuations during trabeculectomy in high-risk cases. In this study, we compared the efficacy and safety of PTB with conventional trabeculectomy surgery.

In this prospective, interventional, nonrandomized, comparative pilot study, certain high-risk cases planned for trabeculectomy were assigned to Group A (conventional trabeculectomy) or Group B (pneumatic trabeculectomy). The primary outcome measure was to assess the anterior chamber (AC) fluctuations (through assessing anterior chamber shallowing/collapse), the frequency of need to form AC, and the occurrence of any intra-operative/early postoperative complications.

Of the 48 eligible participants, 24 were assigned to Group A and Group B. The mean surgical time required to complete the surgery was 17.63 ± 1.44 min in group A and 17.21 ± 1.50 min in group B (p = 0.83). In group A, 83.3% (20/24)eyes, anterior chamber collapsed during the step of scleral osteotomy/iridectomy compared to 4.17% (1/24) eyes in group B (p < 0.001) (Fischer's test). The anterior chamber remained stable throughout the surgery in Group B, while AC formation was required at least twice (mean 2.3 ± 0.7) in eyes undergoing conventional trabeculectomy in group A (p < 0.001).

PTB in high-risk cases had a significantly lower incidence of intra-operative anterior chamber collapse, requiring less frequent AC reformations, making it a safer alternative to conventional trabeculectomy.