
==== Front
Sci Rep
Sci Rep
Scientific Reports
2045-2322
Nature Publishing Group UK London

39223204
71469
10.1038/s41598-024-71469-1
Article
Comparative efficacy of probing with or without intubation, and/or inferior turbinate fracture in simple congenital nasolacrimal duct obstruction: a randomized clinical trial
Soltani Shahgoli Sahel 1
Zand Amin 1
Jamshidian Tehrani Mansooreh 2
Bahremani Erfan 3
Rajabi Mohammad Taher 2
Aghajani Amirhossein 2
Rafizadeh Seyed Mohsen mohsen_raf1354@yahoo.com

2
1 grid.411705.6 0000 0001 0166 0922 Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
2 grid.411705.6 0000 0001 0166 0922 Department of Oculofacial Plastic and Reconstructive Surgery, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
3 https://ror.org/04krpx645 grid.412888.f 0000 0001 2174 8913 Nikoukari Eye Center, Tabriz University of Medical Sciences, Tabriz, Iran
2 9 2024
2 9 2024
2024
14 203249 5 2024
28 8 2024
© The Author(s) 2024
2024
https://creativecommons.org/licenses/by-nc-nd/4.0/ Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
To compare the success rates of probing with or without monocanalicular intubation, and/or inferior turbinate fracture in resolving simple congenital nasolacrimal duct obstruction (CNLDO). A randomized, double-blind clinical trial was conducted on children aged 12–36 months exhibiting symptoms of epiphora and/or mucous discharge along with a positive fluorescein dye disappearance test (DDT). Patients were randomly assigned to one of the following interventions: (1) probing; (2) probing and monocanalicular intubation; (3) probing and inferior turbinate fracture; (4) probing, inferior turbinate fracture, and monocanalicular intubation. Participants were categorized into two age groups (12–24 months and 24–36 months) and assessed for resolution of CNLDO three months post-surgery. Success was defined as the absence of epiphora or mucopurulent discharge and a negative DDT. Among the 201 participants, 51 underwent probing alone, 53 underwent probing with intubation, 47 underwent probing with turbinate fracture, and 50 underwent probing with turbinate fracture and intubation. No significant differences were observed in age, gender, or laterality of the disease between the groups (Ps > 0.05). While there was no significant difference in success rates among interventions in both age groups (Ps > 0.05), patients aged 24–36 months who underwent interventions involving intubation exhibited a significantly higher success rate compared to those without intubation (93.0% vs. 76.2%; P = 0.018). However, this difference was not observed in patients aged 12–24 months (95.7% vs. 92.9%; P = 0.551). Incorporating interventions such as intubation and/or turbinate fracture alongside conventional probing does not significantly alter the success rate of simple CNLDO resolution in children aged 12–24 months. However, older patients (24–36 months) may derive greater benefits from interventions involving intubation.

Keywords

Congenital nasolacrimal duct obstruction
Probing
Intubation
Monocanalicular
Turbinate fracture
Randomized clinical trial
Subject terms

Lacrimal apparatus diseases
Eye manifestations
issue-copyright-statement© Springer Nature Limited 2024
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pmcIntroduction

Congenital nasolacrimal duct obstruction (CNLDO) affects approximately 20–30% of newborns, often manifesting with symptoms such as epiphora and/or mucopurulent discharge from the eye1,2. While conservative management, including hydrostatic massage and topical antibiotics, is typically employed in the first year of life, spontaneous resolution occurs in over 90% of cases by this age1,3. However, persistent symptoms beyond the first year may necessitate intervention, with probing being the procedure of choice due to its high success rates4,5.

A conventional treatment approach for CNLDO involves initially considering a single procedure for all cases preoperatively, with additional procedures pursued if the initial attempt fails. In this approach, termed "one procedure for all", advancing age is regarded as the primary reason for the failure of primary probing3,6. Conversely, some researchers argue that the type of CNLDO, rather than age, is the primary factor in the failure of primary probing. They contend that simple (membranous) CNLDO cases can be adequately managed with less invasive procedures such as simple probing, whereas complex types require more invasive interventions such as intubation, inferior turbinate fracture, or balloon dilation. This obstruction-based approach considers CNLDO as a heterogeneous disease and tailors treatment based on intraoperative findings during probing, especially when guided by nasal endoscopy7,8. However, considering lower success of probing in older children, various combined interventions, such as nasolacrimal intubation and/or inferior turbinate fracture alongside probing or ballooning, have been documented in the literature9–11. These combined procedures may yield higher success rates, particularly in older patients, cases with complex disease presentations, or those with a history of unsuccessful probing attempts10,12,13. Presently, many clinicians favor probing with monocanalicular intubation as a primary procedure for CNLDO14,15. Alternatively, probing combined with inferior turbinate fracture may be suitable for cases with a history of failed probing, particularly in individuals with inferior turbinate hypertrophy11. Another treatment modality involves the combination of probing, canalicular intubation, and inferior turbinate fracture16.

With the multitude of management methods available for CNLDO and the challenges involved in selecting the most suitable approach for each case, coupled with discrepancies among treatment approaches, there arises a necessity to compare the outcomes of the treatment methods across various age groups. Therefore, this study represents the first randomized clinical trial to compare the success rates of probing with or without monocanalicular intubation and/or inferior turbinate fracture in cases of simple CNLDO.

Methods

Study design

The reporting of this study conforms to CONSORT guidelines17. This randomized, double-masked, controlled trial was conducted at the oculoplastic department of Farabi Eye Hospital in Tehran, Iran, between 01/04/2022 and 31/10/2023. The trial adhered to the principles of the Declaration of Helsinki, and written informed consent was obtained from the parent or guardian of each study participant. The study protocol was registered on the Iranian Clinical Trials Registry System (IRCT) website (https://irct.behdasht.gov.ir/trial/61428) under registration number IRCT20220120053771N1 as of 02/02/2022. Approval for the study protocols was obtained from the ethics committee of Tehran University of Medical Sciences, Tehran, Iran (Ethics Code: IR.TUMS.FARABIH REC.1401.006).

Subjects

Children aged 12–36 months with nasolacrimal duct obstruction (NLDO) were eligible for inclusion. The participants were selected using convenience sampling and enrolled consecutively based on specific criteria. Eligible participants were randomly assigned to the four intervention groups: (1) probing; (2) monocanalicular intubation; (3) probing and inferior turbinate fracture; (4) monocanalicular intubation and inferior turbinate fracture. Inclusion criteria encompassed symptom onset before 6 months of age, presence of epiphora and/or mucopurulent discharge, and a positive fluorescein dye disappearance test (DDT). The DDT, performed without topical anesthesia, evaluated dye disappearance after 3 min. It was considered negative (grades 0–1) if the dye disappeared or there was faint dye in the tear film. If pooling of the dye was presented (grades 3–4) it was considered positive18. If both eyes of a patient met the inclusion criteria, treatment was performed on both eyes in the same session. However, only one eye per participant was randomly selected for inclusion in the study. The selection was made using an R programming language function that generated a random sequence of left (coded as 0) and right (coded as 1) eyes19. Patients with simple (membranous) CNLDO were enrolled. It was defined as a membranous obstruction at the lower end of the nasolacrimal duct that is overcome with minimal resistance5,7. Exclusion criteria included upper respiratory infection, ocular surface irritation, prior nasolacrimal system trauma or surgery, complex disease presentations (the probe can be eventually retrieved from the nose or cannot be passed into the nose)5,7, acute dacryocystitis history, systemic disease contraindications for general anesthesia, craniofacial abnormalities, and Down syndrome. Furthermore, cases with any preexisting endonasal pathologies, such as septal deviation or turbinate hypertrophy, were excluded.

Randomization and intervention

Participants were randomly assigned (by S.S.) using computer-generated randomization lists created with Randlist software, and were allocated in a 1:1:1:1 ratio to the four intervention groups. Under general anesthesia, all participants underwent irrigation tests to confirm CNLDO. Probing involved dilation of the inferior punctum and passage of a Bowman's probe (size 0 or 00) through the nasolacrimal duct, with patency confirmed via metal-on-metal contact using a Crawford hook20. Monocanalicular intubation employed a medium Monoka tube (Crawford guided) inserted into the lower canalicular system via a Fayet-Bernard metal probe14,21. Inferior turbinate fracture was performed by positioning a blunt periosteal elevator in the inferior meatus adjacent to the outer edge of the inferior turbinate, followed by inward pivoting towards the septum and fracture at the base11.

Postoperative care

Following surgery, all participants received topical betamethasone 1% and chloramphenicol 0.5% every 6 h for one week. Intubated cases had tube's removal after 2 months. Surgeries were performed by a single oculoplastic surgeon (S.M.R), and the trial remained double-masked to ensure anonymity of subjects, investigators, and site staff until its conclusion.

Outcomes

Resolution of treatment success was defined as absence of epiphora or purulent discharge for 3 months post-surgery, along with a negative DDT14,22.

Statistical analysis

Data analysis utilized SPSS software version 29 (SPSS Inc., Chicago, IL, USA). Continuous variables were presented as mean ± standard deviation (SD), and categorical variables as percentages. Intergroup comparisons were performed using the Mann–Whitney and Kruskal–Wallis tests, with logistic regression employed to compare success likelihood among groups and adjust for potential age and sex effects. Statistical significance was set at P < 0.05.

Results

Subject dispositions

Among 287 individuals screened, 86 were excluded from the study: 53 declined participation, 7 cancellations of scheduled operations, and 26 due to complex CNLDO. Of the 201 individuals randomized, 51 were allocated to probing, 47 to probing with inferior turbinate fracture, 53 to monocanalicular intubation, and 50 to monocanalicular intubation and inferior turbinate fracture. No participants were lost to follow-up, and all were included in the analysis.

Baseline characteristics

Table 1 presents the demographic and disease laterality data. No significant differences were observed between groups regarding age, gender, or laterality of the disease (Ps > 0.05).Table 1 Baseline demographic and disease characteristics of the participants.

	Groups	P	
Probing, N (%)	Probing and monocanalicular intubation, N (%)	Probing and inferior turbinate fracture, N (%)	Probing, inferior turbinate fracture, and monocanalicular intubation, N (%)	
Age (months)	12–24	29 (56.9%)	23 (43.4%)	27 (57.4%)	23 (46.0%)	0.338	
24–36	22 (43.1%)	30 (56.6%)	20 (42.6%)	27 (54.0%)	
Gender	Female	24 (47.1%)	29 (54.7%)	23 (48.9%)	25 (50.0%)	0.882	
Male	27 (52.9%)	24 (45.3%)	24 (51.1%)	25 (50.0%)	
Laterality	Right	27 (52.9%)	32 (60.4%)	20 (42.6%)	19 (38.0%)	0.100	
Left	24 (47.1%)	21 (39.6%)	27 (57.4%)	31 (62.0%)	
N number.

Clinical outcomes

In the 12–24 months age group, the highest success rates were observed in the monocanalicular intubation and inferior turbinate fracture group (95.7%), followed by monocanalicular intubation (95.7%), probing (93.1%), and probing with inferior turbinate fracture (92.6%), respectively. However, these rates did not significantly differ between groups (P = 0.148, Table 2).Table 2 Treatment success rates in different intervention groups in each age group of patients.

Age group (months)	Probing, inferior turbinate fracture, and monocanalicular intubation, N (%)	Probing and inferior turbinate fracture, N (%)	Probing and monocanalicular intubation, N (%)	Probing, N (%)	P	
12–24	22 (95.7%)	25 (92.6%)	22 (95.7%)	27 (93.1%)	0.148	
24–36	25 (92.6%)	16 (80.0%)	28 (93.3%)	16 (72.7%)	0.243	
N number.

Among children aged 24–36 months, the highest success rates were observed in the monocanalicular intubation group (93.3%), followed by monocanalicular intubation and inferior turbinate fracture (92.6%), probing with inferior turbinate fracture (80.0%), and probing (72.7%), respectively. Nevertheless, these rates did not significantly differ between groups (P = 0.243, Table 2).

Patients aged 24–36 months who underwent interventions including intubation exhibited significantly higher success rates compared to those without intubation (93.0% vs. 76.2%; P = 0.018). Conversely, this difference was not observed in the 12–24 months age group (95.7% vs. 92.9%; P = 0.551). There was no significant difference in success rates between patients with and without turbinate fracture in both age groups (Ps > 0.05, Table 3).Table 3 Comparison of treatment success rates, based on interventions included intubation or turbinate fracture or not, by age groups.

	Success, N (%)	P	
Age group (months)	12–24	Intubation	No	52 (92.9)	0.551	
Yes	44 (95.7)	
Turbinate fracture	No	49 (94.2)	0.961	
Yes	47 (94.0)	
24–36	Intubation	No	32 (76.2)	0.018	
Yes	53 (93.0)	
Turbinate fracture	No	44 (84.6)	0.709	
Yes	41 (87.2)	
N number.

Complications were rare. One patient in the probing and inferior turbinate fracture group experienced nasal bleeding several hours post-procedure, managed with phenylephrine nasal drops. Premature tube removal occurred in two cases: one with monocanalicular intubation and another with inferior turbinate fracture and monocanalicular intubation, 6 and 7 weeks postoperatively, respectively. Tube migration to canaliculus was not observed in any cases.

Discussion

Considering the lower success rate of probing in older children with CNLDO, some investigators have explored alternative interventions such as intubation, inferior turbinate fracture, or balloon dilation as primary treatments for the condition9–11. This age-based approach considers CNLDO as a homogeneous disease, leading to all patients being treated with a single predetermined procedure3,6. In contrast, other investigators argue for a treatment strategy that targets the underlying issue, regardless of age or prior unsuccessful procedures. This approach, known as the one-stage approach, categorizes patients based on the type of obstruction (simple or complex). Patients with simple CNLDO may only require probing, while those with complex cases may benefit from additional interventions such as intubation, inferior turbinate fracture, or balloon dilation. All surgical options are considered viable in this approach, with the procedure of choice being individualized and determined intra-operatively7,8. In consistent with these findings, our randomized clinical trial reveals adding interventions including intubation and/or turbinate fracture to conventional probing will not change the success rate of simple CNLDO resolution in ages between 12 and 24 months, significantly. However, in older cases (age between 24 and 36 months) interventions, which include intubation, may have higher success rates for resolution of the disease. Therefore, surgeons' preferences for simple CNLDO treatment should consider factors such as patient age, surgical skills, available instruments, and parental preferences.

The success rates observed in our study align with previous literature. Probing alone has been shown to resolve CNLDO in 70–97% of cases, consistent with our rates of 93.1% and 72.7% for the 12–24 and 24–36 months age groups, respectively5,22,23. Similarly, the success rates after monocanalicular intubation in our study (95.7% and 93.3% for 12–24 and 24–36 months age groups, respectively) are comparable to previous studies reporting success rates between 79 and 96%13,24,25. Furthermore, the success rates for probing combined with inferior turbinate fracture in our study (92.6% and 80.0% for the 12–24 and 24–36 months age groups, respectively) are consistent with previous findings. Rajabi et al.11 reported combination of probing and inferior turbinate fracture had 91.2% success rate in 12–36 months old cases with CNLDO.

Our results regarding the efficacy of intubation alongside probing are consistent with existing literature. While some studies have shown no significant difference in success rates between probing with and without intubation, others have demonstrated higher success rates with intubation, particularly in cases of complex CNLDO or in older children20,23,26–29. In a clinical trial by Han et al.26 the investigators showed the success rates of probing with and without intubation were 94.23% and 92.08%, respectively, with no significant differences. A meta-analysis revealed that the use of intubation alongside probing in cases related to simple CNLDO did not significantly increase the success rate (87% for probing versus 92% for probing and intubation), while in cases of complex CNLDO, it significantly improved the success rate (46% for probing vs. 82% for probing and intubation)20. Some previous studies showed advanced age is related with higher rate of probing failure in cases with simple NLDO, and in these cases combined treatment with intubation may have more benefits, especially in children older than 2 years of age23,27–29. Similarly, we showed a significant higher resolution rates with intubation in children aged 24–36 months but not in those aged 12–24 months. In a study conducted by Rajabi et al.11 on 12–24 months old children with CNLDO, they showed the success rate of probing and inferior turbinate fracture was higher than the probing alone (91.2% vs. 86.4%), whereas this difference was not statistically significant. Another study by Attarzadeh et al.30 revealed the success rate of combined probing and inferior turbinate fracture were statistically not different from probing alone in > 6 months old children with CNLDO (91% vs. 82%). In consistent with these studies, we found inferior turbinate fracture has no additional benefit to decrease probing failure in cases with simple CNLDO.

Although our study provides valuable insights, it is not without limitations. The small sample size in each group and the relatively short 3-month follow-up period may have impacted our analyses. Moreover, the omission of nasal endoscopy during probing may lead to overlooking intraoperative findings associated with complex types of the disease, potentially impacting the accuracy of our results. Additionally, the single-center nature of the study limits generalizability, and further multi-center studies with larger sample sizes and longer follow-up periods are warranted. Furthermore, our study did not assess the impact of CNLDO on the health-related quality of life of parents and children, nor did it compare changes in quality of life after intervention between different surgical methods31.

In conclusion, our study underscores the importance of tailoring simple CNLDO treatment strategies to individual patient characteristics, particularly age. While additional interventions such as intubation may offer higher success rates in older children, they may not significantly impact outcomes in younger children.

Acknowledgements

The authors are grateful to the research participants and all the hospital staff who took interest and helped out in the study.

Author contributions

Conceptualization and study design: SMR; data acquisition: SMR, AZ, MTR, AA, and SSS; data analysis/interpretation: SSS and MJT; statistical analysis: SSS and SMR; supervision/mentorship: SMR and MJT; drafting of the manuscript: SSS, EB, and AZ; responsibility of submitting for publication: SSS. All authors had a critical role in revision of the manuscript for important intellectual content. The final manuscript was read and approved by all authors.

Data availability

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

Competing interests

The authors declare no competing interests.

Ethical approval

The study was approved by the ethics committee of Tehran University of Medical Sciences (ethics code: IR.TUMS.FARABIH REC.1401.006). The study was explained to eligible participants and written informed consents were obtained. The study was in accordance with Declaration of Helsinki and the national guidelines and regulations. The protocol of the study was registered in the Iranian clinical trials registry system (code: IRCT20220120053771N1) as of 02/02/2022 and is accessible at https://irct.behdasht.gov.ir/trial/61428.

Publisher's note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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