Epiphora in the pediatric population often originates from a disorder of the lacrimal drainage system. In most cases, the cause is congenital nasolacrimal duct obstruction (CNLDO), which often presents during the first year of life, with a prevalence ranging from 1.2% to 6% ( Fig. 16.1 ). Additional symptoms and signs of CNLDO may include a high tear meniscus, positive dye disappearance test result, recurrent mucopurulent discharge, and reflux of lacrimal sac contents with digital pressure.
The nasolacrimal drainage system arises during the third month of fetal development. A rudimentary drainage system initially forms from the cord of epithelium between the maxillary and frontonasal recesses. Canalization then occurs uniformly throughout its entire length. The lateral portion of the cord differentiates into the ocular end with the creation of the superior and inferior canaliculi. In the sixth month of fetal development, the medial portion of the cord canalizes to create a drainage communication with the inferior nasal meatus. Incomplete canalization leading to a residual membranous barrier between the nasolacrimal duct and the nasal cavity at the level of the valve of Hasner is the most common cause CNLDO. Jones and Wobig have also described seven other anatomic variations that cause obstruction of the lower nasolacrimal duct system ( Box 16.1 ). These variations constitute a significant cause of failure for spontaneous CNLDO resolution and are theorized to contribute to cases of failed nasolacrimal duct probing.
The duct extends to the floor of the nose lateral to the nasal mucosa.
The duct extends several millimeters down lateral to the nasal mucosa without an opening.
The duct fails to canalize owing to failure of osseous nasolacrimal canal formation
An impacted inferior turbinate blocks the duct meatus.
The duct ends blindly in the anterior end of the inferior turbinate.
The duct ends blindly in the medial wall of the maxillary sinus.
A bony nasolacrimal duct extends to the floor of the nose without an opening ( Fig. 16.2 ).
Because neonatal tear secretion does not reach adult volume until 4 weeks after birth, CNLDO symptoms are not typically seen in newborns. Symptomatic infants may attain spontaneous absorption of the membranous obstruction at the valve of Hasner up to 6 to 8 months of age. Nasolacrimal duct probing and irrigation are typically used for persistent obstruction. Endoscopy is a powerful addition to the typically blind nasolacrimal duct probing, as it minimizes nasal mucosa trauma, decreases the chance of creating a false passage, and provides an optimum management option of different congenital variants of CNLDO.
Simple Congenital Nasolacrimal Duct Obstruction
Spontaneous resolution of CNLDO is seen in 85% to 96% of children by 1 year of age, so conservative management is recommended with lid hygiene, topical antibiotic drops, and a hydrostatic massage known as a Crigler massage. Digital pressure is applied on the common canaliculus with firm downward pressure onto the lacrimal sac to increase hydrostatic pressure, leading to the rupture of the membranous obstruction. There is no definitive consensus on the timing of intervention for children with persistent CNLDO, and probing and irrigation with the patient under general anesthesia is often delayed until 12 months of age and has a success rate of 55% to 95%. Nasolacrimal duct probing is a reliable primary management of CNLDO; however, this blind procedure mainly depends on the surgeon’s knowledge of anatomy and feel of metal-on-metal contact, or proprioceptive intuition, to determine the location and severity of the obstruction and to confirm the passage of the probe through the inferior meatus. Metal-on-metal contact may traumatize the nasal mucosa surrounding the delicate valve of Hasner. The leading factors implicated in the failure of probing include improper technique, anatomic variations, complex NLDO, inferior turbinate impaction or hypertrophy, or associated nasal pathology. Even with positive metal-on-metal touch, false passages can be created, especially in cases of “buried probe” with the nasolacrimal duct extends into the nose down the submucosa for several millimeters or even to the floor without opening into the meatus, or the duct may end in the medial wall of the maxillary sinus blindly. Adjunctive use of the nasal endoscope has revealed a high incidence of false passage creation with this technique; thus nasal endoscopy is now increasingly used with nasolacrimal duct probing to improve the unexplained variable success rate, anatomic anomalies causing difficulty in probe advancement, and difficulty in accurately identifying the variants of CNLDO. In cases of obstruction caused by collapse of the inferior turbinate onto the nasolacrimal duct ostium, medialization, or fracturing, of the turbinate is also required in addition to probing to improve the outflow tract.
The success rate for the first nasolacrimal probing after 13 months of age is 54.7%. Many recommend probing before 13 months of age, as it is theorized that the risk of infection and scarring increases if probing is postponed. Conversely, other studies on conservative treatment have shown that the timing of probing can be postponed while still achieving a safe, satisfactory outcome with comparable success rates until the child reaches the age of 36 months. Additional factors associated with decreased success are severity of symptoms, bilateral symptoms, canalicular stenosis, atony of the lacrimal sac, and nonmembranous obstruction of the nasolacrimal duct (NLD). Repeat probing with intubation of a silicone stent and sometimes balloon catheter dilation are reserved for cases of failure. When the obstruction is refractory to such measures, or in those children with a more proximal NLDO, dacryocystorhinostomy (DCR) is needed. DCRs have been reported in children as young as 12 to 18 months without disturbance of bone growth; it is recommended that this procedure be deferred until the patient is 2 to 5 years old.
Complex Congenital Nasolacrimal Duct Obstruction
Complex CNLDO can results from other causes of obstruction, including bony obstruction, craniofacial deformities such as congenital facial cleft syndrome, cyclopia, and cryptophthalmos. As clefting can causes abnormalities of the soft tissues and bony structures, Tessier cleft types 2, 3, 4 are located in the lower medial canthal and nasolacrimal area and can lead to abnormalities of the nasolacrimal drainage system. Preoperative imaging with computed tomography scanning can be advantageous for surgical planning. The open cleft may preclude the need for endoscopic visualization.
Dacryocele/Dacryocystocele, and Dacryocystitis
Dacryocele typically appears as a bluish cystic mass just below the medial canthal tendon at birth or, as tear production increases, within the first few weeks of life ( Fig. 16.3 ). Epidemiologically, dacryoceles have a female predominance with a possible genetic predilection and occur more frequently in Caucasians than other racial groups. They may be unilateral or bilateral, although bilateral symptomatic presentation is infrequent.