A Comparison between Pulled and Pushed Monocanalicular Silicone Intubation in Management of Congenital Nasolacrimal Duct Obstruction

Background: Congenital nasolacrimal duct obstruction (CNLDO) is usually caused by a membranous block at the valve of Hasner. Symptoms of CNLOD include epiphora, mucous discharge, or mucopurulent discharge. Many CNLDOs can resolve spontaneously by the first year of life. Children who ultimately have unsuccessful responses to canalization will undergo invasive procedures for CNLDO, including probing, silicone intubation, balloon dacryocystoplasty and dacryocystorhinostomy. There are two types of lacrimal intubation, monocanalicular and bicanalicular. Pushed monocanalicular stent is characterized by the probe guide actually placed inside the silicone tube, rather than attached at the end as in conventional ‘‘pulled’’ intubations stents.
Aim of the work: was to compare the success rate of pulled monocanalicular (MCI) versus pushed monocanalicular silicone intubation (PMCI) of the nasolacrimal duct for congenital nasolacrimal duct obstruction.
Patients and methods: In a prospective randomized clinical trial 67 eyes of 67 patients with CNLDO underwent either pulled monocanalicular silicone intubation (MCI) (=32 eyes) or PMCI ( =35 eyes).      Cases were considered successful if reached grade 0 or 1 in fluorescein dye disappearance test -complete or partial resolution of symptoms - after two months after tube removal.
Results: This study included only patients with simple obstruction at the level of the Hasner valve and diagnosed intraoperative during the initial probing thus, the surgical outcome was assessed in 30 eyes of 30 patients in the MCI groups. 15 eyes received MCI in the upper punctum and 15 eyes received MCI in the lower punctum. The other 30 eyes 30 patients did PMCI with Masterka tube. 15 eyes received PMCI in the upper punctum and 15 eyes received PMCI in the lower punctum. 33 females (55%) & 27 males (45%) with age ranged from 12 to 46 months with mean of 26 ± 11 months. Follow-up of the patients was done at 1 week, 1 month, 2 and 3 months post-operative. Tube removal was done 3 months post operatively in both types of tube. The overall success rate in the MCI intubation groups was 86.7%, whereas in the PMCI intubation groups was 80%. However, the difference in the success rates between the two groups was statistically insignificant (P= 0.4884) using Chi-square test.
Conclusion: Results indicate that MCI has higher success rate in CNLDO treatment compared with PMCI in this small series of patients.