Lacrimal dilator-facilitated incisionless vs. standard sub-Tenon’s block: a randomized, prospective and non-inferiority comparative study

Abstract

Background/objectives: Standard sub-Tenon’s block (STB) involves incision (dissection) of conjunctiva and Tenon’s capsule with the help of blunt scissors and forceps, insertion of a blunt sub-Tenon’s cannula under the Tenon’s capsule and injection of local anaesthetic agent. STB is frequently associated with minor complications such as chemosis and postoperative subconjunctival haemorrhage but rare sight and life-threatening complications. To reduce these minor complications, several variations of incisionless STB have been described however, there are no comparative data. One such incisionless STB involves the use of lacrimal dilator which is easily available in the operating theatre. We compared incisionless lacrimal dilator-facilitated with the standard STB for effectiveness, chemosis, and postoperative subconjunctival haemorrhage. Subjects/methods: After obtaining ethical approval, patients scheduled to undergo elective phacoemulsification cataract surgery were enroled to receive incisionless lacrimal dilator-facilitated STB (Group LD) or a standard STB using Wescott scissors and blunt forceps (Group WS). All patients received 3 mL 2% lidocaine without any adjuvant. No sedation was administered. Demographics of the patients, duration of the procedure, analgesia, akinesia, duration of the procedure intraoperative chemosis, and postoperative subconjunctival haemorrhage were compared. Results: Both groups were comparable for demographic data, duration of the procedure, analgesia, and akinesia (p > 0.05). The severity of chemosis and postoperative subconjunctival haemorrhage were significantly lower in Group LD (n = 32) in comparison to Group WS (n = 31) (p < 0.001). Conclusions: Incisionless lacrimal dilator-facilitated STB decreases intraoperative chemosis and postoperative conjunctival haemorrhage in comparison to standard STB. Analgesia and akinesia are comparable in both techniques.