Kuchar and Steinkogler used antegrade balloon DCP combined with silicone stent intubation for 3 to 6 months for complete NLDO, and the success rate was 90% at 3 months and 70% at 6 months postoperatively . In the present study, antegrade balloon DCP was combined with pushed-type MCI intubation for only 1 month, which is the shortest reported intubation duration to date [5–9, 12–14, 16]. Our success rate at 3 months postoperatively seemed lower when compared to a previous study in which antegrade balloon DCP with silicone stent intubation was combined (73.0% vs. 90%, respectively), but the result was similar at 6 months postoperatively (70.2% vs. 70%) . Since a longer postoperative follow-up period has been suggested, the differences between previous studies and the current study at 3 months and 6 months postoperatively were not significant [13, 17]. Also, the current study revealed that the additional pushed-type MCI for antegrade balloon DCP did not significantly improve the surgical outcomes in general since the success rates were not significantly higher at 3 months and 6 months postoperatively despite the significantly higher success rate at 1 month postoperatively.
A randomized trial conducted by Andalib et al. compared bicanalicular intubation (BCI) and MCI for partial PANDO, revealing no significant differences in the surgical outcome between the two . However, to date, there have been no comparative studies for complete PANDO. Mimura et al. reported a clinical success rate of 91.7% at 6 months postoperatively using BCI for complete PANDO without canaliculi involvement, while Inatani et al. reported a success rate of 68% [14, 15]. However, surgical outcomes for MCI for complete PANDO have not yet been studied.
We favored MCI stents because repeated manipulations at the inferior meatus were not required during intubation. In addition, despite the use of prophylactic antibiotics, the postoperative infection rate with BCI for complete PANDO has been reported in previous studies to be as high as 9.5% [12, 14]. Furthermore, a high punctal laceration rate (13.6%) was also reported by Kashkouli et al . Among MCI stents, the pulled-type MCI was still required some intervention at the inferior turbinate while the pushed-type one did not . We chose the pushed-type MCI in this study since it was easier to perform than the pulled-type.
To our knowledge, our study is the first to compare the differences in success rates between patients younger than 65 years old and those older than 65 for balloon DCP and silicone stent intubation. Interestingly, we found the success rates when combining balloon DCP with pushed-type MCI were always significantly higher than when using balloon DCP alone in patients younger than 65 years old regardless of the postoperative timing. On the other hand, there were no significant differences found in the success rates between patients receiving balloon DCP combined with pushed-type MCI and those receiving balloon DCP alone if the patients were aged over 65 years old. We assumed that it was resulted from the silicone stent, which was intubated for 1 month, played an important role especially in patients younger than 65 years old with complete PANDO by maintaining the patency of the nasolacrimal duct just as the surrounding tissue began to scar , while balloon DCP only creates a perioperatively patent nasolacrimal duct (NLD). The stent intubation might weigh more in younger patients due to the increased inflammation and possibility of adhesion from their better healing ability and significant inflammatory reaction. By combining balloon DCP with pushed-type MCI, the patency of the NLD was maintained by avoiding excessive scarring, and consequently resulted in a better surgical outcome.
DCR is currently considered the standard treatment for PANDO due to its high success rate, which was reported with approximately 90% [1, 2, 4]. When it comes to complete PANDO, DCR has also been suggested as the gold standard. Nevertheless, DCR resolves the PANDO at the cost of invasiveness, such as osteotomy regardless of whether the approach is endonasal or external. In order to decrease the level of invasiveness and bleeding while operating, transcanalicular laser-assisted DCR was developed as an alternative to the conventional DCR by Michalos et al . However, a recent study conducted on transcanalicular laser-assisted DCR by Ayintap et al. revealed a significantly lower success rate in younger patients with complete PANDO that the overall success rate in patients younger than 65 years old was approximately 62% at 2-year follow-up, which was lower than the success rate in the present study with 72.7% at 6-month follow-up .
Although our overall long-term success rates with balloon DCP combined with pushed-type MCI (70.2%) did not achieve that using conventional DCR (around 90%), the procedure still yielded several advantages. First, no general anesthesia was required for our surgical methods. Second, we minimized the degree of invasiveness by preserving the original nasolacrimal system instead of performing an osteotomy. Third, our method did not require further manipulation of the inferior nasal meatus; thus, we decreased the possibility of significant bleeding. Last but not least, no postoperative complications were found after antegrade balloon DCP with the pushed-type MCI in current study.
The current study was limited by its retrospective and non-randomized design. Also, we did not use any radiographic assistance to confirm the diagnosis of complete PANDO; for example, transcanalicular endoscopy or dacryocystography [10, 13]. In addition, we did not perform subjective parameters such as the Munk score as the outcome parameter since some of the patients suffered from dry eye, which may also present with epiphora due to reflex tearing. In addition, our case number was relatively small, which may limit the statistical power. Current results implied efficiency and few complications with antegrade balloon DCP followed by pushed-type MCI for patients with complete PANDO at 6 months postoperatively, and further large-scaled investigations with longer follow-up duration were needed for a more definite long-term result.
In general, the combination of balloon DCP and pushed-type MCI did not lead to a significantly higher success rate as compared to balloon DCP alone for complete PANDO. However, in patients under 65 years old with complete PANDO, the combination of balloon DCP and pushed-type MCI was associated with significantly higher surgical success rates as compared to balloon DCP alone. In addition, the former procedure had several advantages over DCR, including its non-invasiveness and the avoidance of general anesthesia as well as hospitalization for postoperative care. Balloon DCP followed by pushed-type MCI could be of value when it comes to treating complete PANDO in younger patients and it could also serve as an alternative for the elderly who are poor candidates for general anesthesia.