Recent Methods in Treatment of Congenital Nasolacrimal Duct Obstruction

Abstract

Congenital nasolacrimal duct obstruction (CNLDO) is the most common abnormality of the lacrimal system in childhood, occurring in 20-30% of the newborns. Most obstructions open spontaneously within 4-6 weeks after birth. CNLDO is usually caused by a membranous block of the valve of Hasner and becomes clinically evident in 6%. Rarely, there may be other associated abnormalities or agenesis of the puncta, lacrimal sac, or absence of valves (valve of Hasner ± valve of Rosenmüller). Approximately 80-90% of all symptomatic CNLDO present the symptoms within one month of age, which include epiphora, mucous or mucopurulent discharge accumulating at lid margin & eye lashes. The physical examination may show swollen lacrimal sac with inflammation, & reflux of mucoid or mucopurulent material from punctum when pressure applied over lacrimal sac, the eye is otherwise white. Fluorescein dye disappearance test may also be helpful (a functional test which is useful in children) place Fluorescein in both eyes, check in 10 min; Fluorescein will remain in the eye with CNLDO. Other investigations may be used include: contrast dacryocystography (DCG), CT scan, CT with dacryocystography & lacrimal scintigraphy. Because spontaneous resolution occurs in 80-90% of affected infants by one year of age, Urgent treatment of CNLDO is usually unnecessary. Patient infants undergo conservative management including warm compresses, massage of the lacrimal sac & intermittent use of topical antibiotics ointment or drops. Lacrimal sac massage has been proposed as helping to open the duct by increasing hydrostatic pressure in the sac & rupturing the membranous obstruction, Which can be performed by placing the index finger over the common canaliculus to block reflux through the puncta & then massaged firmly downwards, Ten strokes are applied four times a day. Massage should be accompanied by lid hygiene; Topical antibiotics should be reserved for super added bacterial conjunctivitis. The timing of probing for CNLDO obstruction has been a matter of controversy in recent years. Many reports have shown that delay in probing until after 13 months is associated with a decreasing success rate which may be caused from chronic inflammation in the lacrimal drainage system. On the other hand, other reports have shown a high success rate from probing in children older than two years without an age related decline in success. Probing is still accepted as the most useful method for CNLDO in older children. Failed initial probing may be followed by 2nd probing, which can be associated with in fracture of the inferior turbinate especially for children younger than 18-24 months of age. For older children (typically older than 18 months) or those with more complex obstruction noted during initial probing or both, probing with silicone intubation has a greater likelihood of success. Intubation may be performed blind or under direct intranasal endoscopic visualization. Many types of intubation sets are described including: the bicanalicular silicone intubation, which is the most commonly, used techniques, as well as the monocanalicular silicone tubing. Recently, silicone intubation with Ritleng system has been found to be an effective treatment for patients with CNLDO, especially at young age. Balloon catheter dilatation of the NLD has been recently successfully used in CNLDO. Although early results seem promising, the role of this modality has not been defined. As the necessary of catheter equipment, this modality is expensive treatment comparing with simple probing which has a high success rate. Thus balloon catheter dacryoplasty is now limited to difficult cases or probing failures. In patients for whom those procedures fail to establish and maintain patency of NLD or whom have a malformation of the lacrimal drainage anatomical structures, dacryocystorhinostomy (DCR) can be performed to bypass the NLD. Since the development of functional endoscopic sinus surgery, the endonasal approach has become an alternative to the conventional external approach.