Congenital nasolacrimal duct obstruction (CNLDO) is a common cause of epiphora in young children1–4 that affects up to 20% of all newborns.5,6 Spontaneous resolution occurs in 80% to 96% of affected infants, and only 1% to 6% of these children become symptomatic.1,3 Standard management includes hydrostatic massage with topical antibiotics, which has a high success rate within the first 12 months.1–4,7 Probing is a standard therapeutic procedure where the condition persists beyond several months of conservative treatment. Although the results of probing in young children (younger than 2 years) are predictably good, controversy exists regarding the outcome of probing in older children.6,8,9 Some authors reported that increasing age significantly decreased the success rate of probing beyond the age of 1 year.6,8,10 Therefore, some clinicians prefer to perform silicone intubation as the initial surgical procedure for older children (typically older than 18 months) with CNLDO.11 However, some investigators reported that increasing age had no significant effect on the success rate of the probing in older children.12–15
There are two hypotheses for the lower cure rate of probing in older children with CNLDO: prolonged inflammation and fibrosis in the lacrimal drainage system with increasing age4,6,10–15 or the result of accumulation of complex obstruction with time as less severe obstruction clears spontaneously.10,11,14
The objective of the current study was to assess the success rate of probing in children older than 2 years.
Patients and Methods
In this prospective interventional case series, 110 eyes of 94 consecutive patients between 2 and 8 years old with CNLDO were probed under general anesthesia by one surgeon (VLU) from June 2016 to May 2017. The study was approved by the institutional research ethics committee. An informed consent was obtained from all parents or guardians of each study patient.
CNLDO was diagnosed clinically by the presence of epiphora beginning during the first few weeks of life and presence of at least one sign of CNLDO (epiphora, increased tear lake, and/or mucopurulent discharge or reflux of contents of the lacrimal sac with pressure in the absence of upper respiratory tract infection, ocular surface irritation, or glaucoma). Patients with a history of previous probing or trauma, punctal agenesis, and associated ocular disease were not included in the study. Six patients had punctal agenesis and were excluded from our study.
All procedures were performed under general anesthesia. During the procedure, punctum dilatation was followed by probing with Bowman's probes of increasing sizes. Initial probing was performed by Bowman's probe size 00 (0.90-mm diameter) followed by probe size 0 (1 mm), then 1, 2, and 3. Probing was carried through the upper puncta. Once the probe entered the canaliculus, it was passed until the hard medial wall of the lacrimal fossa was felt. At this time, the probe was turned to enter the nasolacrimal duct and gently advanced until resistance was felt. The breaking of the membrane was felt as the probe advanced to the obstruction. When a firm or hard resistance was encountered during probing, this was recorded as complex CNLDO. The patency of the nasolacrimal system was checked by obstruction of the upper puncta by a punctum dilator and irrigation of fluorescein stained saline from the lower puncta. Flow of saline in the throat was confirmed by placement of a pediatric-sized suction catheter in the throat and passage of fluorescein saline through it.
Each patient received antibiotic-steroid (fluorometholone) eye drops four times daily for 3 weeks. The patients were seen at 1 week, 1 month, and 3 months postoperatively by the operating surgeon. Success of probing was the main outcome measure and was defined as complete remission of signs and symptoms. Another probing was done after 4 to 6 weeks in cases with persistent manifestations. Patients who failed the two attempted probings were referred for endonasal dacryocystorhinostomy. Because the study was done in a government medical college and hospital, where the patient's financial situation has to be taken into consideration, we did not use the alternatives of a silicone stent or balloon catheter because these were not available free of cost. The cost of probing and subsequent endonasal dacryocystorhinostomy did not put any financial burden on the patient.
Patient data were analyzed as mean ± standard deviation using the chi-square test (SPSS, Inc., Chicago, IL).
Of 94 patients (110 eyes), 78 with unilateral and 16 with bilateral CNLDO were included in this study. The mean patient age was 55 months (range: 2 to 8 years), 62 (66%) patients were male, and 32 (34%) were female. CNLDO was present in the right eye of 40 (43%) patients, in the left eye of 38 (40%) patients, and both eyes in 16 (17%) patients.
The children were divided into two groups according to the age at which the probing was performed: 2 to 5 years (52 patients) and 6 to 8 years (42 patients). The mean age was 37 ± 4 months in the 2 to 5 years group and 68 ± 7 months in the 6 to 8 years group. Individual ducts of bilateral cases were considered independently, keeping in view the possibility that they might respond differently.
The success rate was 85% in the 2 to 5 years group and 73% in the 6 to 8 years group. The success rate of the entire cohort was 80%. The oldest child in this study was 8 years old and probing was successful in him. The results in children older than 24 months were encouraging. None of the patients had any surgery or complication related to anesthesia.
There were two types of obstructions encountered during probing: simple and complex. In simple obstruction, the resistance could be easily bypassed with the help of the Bowman's probe and irrigation after probing revealed a patent lacrimal system. However, in complex obstruction the probe could not be bypassed and there was firm resistance to its passage. There were no cases of a difficult valve of Rosenmueller or webbing within the lacrimal sac or nasolacrimal duct.
Chi-square analysis showed no significant difference in the cure rate with increasing age (chi-square value: 1.438; degrees of freedom = 1). The P value of .2305 was not significant.
One month postoperatively, 68 (72%) patients were epiphora free with negative results on fluorescein dye disappearance test, whereas 26 (28%) patients had persistent manifestations and needed another probing; of these, 3 had complex obstruction. The second probing was successful in 7 (27%) patients (including 1 complex obstruction) and failed in 19 (73%) patients. By the end of the follow-up period, 75 (80%) patients had a successful outcome and 19 (20%) patients failed. Of the failed cases, 50% were older than 5 years. The success rate was 33% for complex obstruction and 80% for simple obstruction. Nineteen (20%) patients who failed a second probing were referred for endonasal dacryocystorhinostomy.
Atresia of the nasolacrimal duct or dacryostenosis is the most common cause of epiphora in the pediatric population. It is thought to result from failure of the canalization of the column of epithelial cells that form the nasolacrimal duct. The most common site of obstruction is at the mucosal entrance into the nose (valve of Hasner) under the inferior turbinate.16
Probing has been a proven treatment for CNLDO. There is controversy regarding the timing of probing and its outcome in older children.6,9,12,17 Recent studies show encouraging results of probing in older children.
An overall success rate of 80% was found in this study, which is comparable with the success rate in early probing done around the first year of life. Kashkouli et al.,18 El-Mansoury et al.,14 Zwaan,13 and Honavar et al.19 found similar success rates of greater than 80% in initial late probing. Robb12 found no prominent effect of age on the cure rate of probing, reporting a cure rate of 94% in children older than 2 years who underwent probing.
On the other hand, Sturrock et al.20 reported that 86% of those probed who were younger than 1 year were corrected, compared to 72% of patients between 1 and 2 years of age and 42% of patients who were 2 years old. Katowitz and Welsh6 found that late management of CNLDO not only decreased the cure rate, but also increased the number and complexity of future procedures. Maheshwari and Maheshawri21 found that age older than 5 years significantly affected the outcome. We had cure rates of 72.91% in children older than 5 years as compared to 85.48% in those younger than 5 years, which is comparable.
The Pediatric Eye Disease Investigative Group (PEDIG) randomized clinical trial comparing early office-based probing with a 6-month period, followed by late probing in a surgical facility, reported similar resolution rates between the two interventions.22 The authors found that early probing reduced overall symptoms at 3 months and was slightly more cost-effective in comparison with the deferred procedure; however, the possibility of resolving CNLDO in two-thirds of the patients with only simple observation should be taken into consideration.
The PEDIG study analyzed the clinical efficacy of repeated probing in children with relapsing CNLDO aged 6 to 48 months in a multicenter, non-randomized, prospective study and found an overall success rate of 56% after the 6-month follow-up period.23 The success rate of repeated probing in our study was 27%.
Paul and Shepherd10 assumed that lower success in older children might be due to a self-selection process. These children may represent the pool of children with a more complicated type of obstruction. Kashkouli et al.18 and Honavar et al.19 showed that complex CNLDO was more likely to be found in older children, with a subsequent lower success rate. Kushner11 even suggested that a reasonable approach to older children with CNLDO is to plan a probing procedure with possible alternative surgical plans if a complex obstruction is found. In the current study, 3 patients only had complex CNLDO. A lower success rate (33.3%) in patients with complex obstruction was found compared to the 80% success rate with simple obstruction in our study, similar to Kashkouli et al.'s18 success rate of 90.2% for membranous and 33.3% for complex CNLDO.
Statistical analysis confirmed that there was no significant difference in success rate between age groups. This observation concurs with previous studies.12–14,18,19
Probing is an invasive and blind procedure that is not free from complications such as bleeding, damage to the nasolacrimal system and the adjacent structures, and inflammation with subsequent nasolacrimal duct fibrosis.24 Nasolacrimal intubation is an invasive technique initially considered for the resolution of persistent CNLDO, consisting of the placement of a silicone tube stent in one or both canaliculi.25,26 Balloon catheter dilatation is a more recent procedure that works by dilating the nasolacrimal duct through balloon inflation and was shown to reduce the probing-induced complications.27,28 In a non-randomized, prospective, multicenter study by PEDIG enrolling 159 children aged 6 to 48 months after failed probing, balloon catheter dilation demonstrated a resolution rate of 77% (95% confidence interval = 65 to 85) in comparison with 88% for intubation (95% confidence interval = 74 to 91) over a 6-month follow-up period.29
Although nasolacrimal intubation has shown considerable results in the management of CNLDO, the invasiveness of this procedure is associated with complications such as dropout rate, damage to the puncta, corneal or conjunctival abrasions, and granuloma formation and thus should be regarded more as an effective second-line strategy.30,31 The high cost of the equipment required for the balloon catheter dilatation should also be considered an efficient treatment modality in the management of complex cases of CNLDO.32 As a last resort, endoscopic dacryocystorhinostomy has proven to be a viable and effective second-line treatment, but probing is considered the first-line treatment for CNLDO.
In our study, we decided to proceed with probing as a prelude to more invasive procedures such as silicone intubation, balloon catheter, or endoscopic dacryocystorhinostomy. It was beneficial because most children could avoid the more expensive and slightly more prolonged procedures.
Results indicate that probing is a viable primary surgical option for CNLDO in the older age group and hence should not be withheld in children who are referred late. Increasing age does not affect the success rate of probing.
- Kenneth LP, Katowitz JA. Treatment of congenital nasolacrimal duct obstruction. Ophthalmol Clin North Am. 1991;4:201–209.
- Kerstein RC. Congenital lacrimal abnormalities. In: Bosniak S, ed. Principles and Practice of Ophthalmic, Plastic and Reconstructive Surgery. Philadelphia: W.B. Saunders; 1996:777–783.
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- Paul TO, Shepherd R. Congenital nasolacrimal duct obstruction: natural history and the timing of optimal intervention. J Pediatr Ophthalmol Strabismus. 1994;31:362–367.
- Kushner BJ. The management of nasolacrimal duct obstruction in children between 18 months and 4 years old. J AAPOS. 1998;2:57–60. doi:10.1016/S1091-8531(98)90112-4 [CrossRef]
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- El-Mansoury J, Calhoun JH, Nelson LB, Harley RD. Results of late probing for congenital nasolacrimal duct obstruction. Ophthalmology. 1986;93:1052–1054. doi:10.1016/S0161-6420(86)33621-2 [CrossRef]
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- Kashkouli MB, Beigi B, Parvaresh MM, Kassaee A, Tabatabee Z. Late and very late initial probing for congenital nasolacrimal duct obstruction: what is the cause of failure?Br J Ophthalmol. 2003;87:1151–1153. doi:10.1136/bjo.87.9.1151 [CrossRef]
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