Endoscopic Endonasal Dacryocystorhinostomy with Ostial Stent Intubation Following Nasolacrimal Duct Stent Incarceration

We appreciate doctor Yildirim’s attention and comments on the study describing a novel ostial stent for using in dacryocystorhinostomy (DCR) surgery. In general, for patients with pure acute and/or chronic dacryocystitis, performing endoscopic endonasal dacryocystorhinostomy (EE-DCR) with meticulous preparation of the lacrimal sac flaps, precise anastomosis of the lacrimal sac and nasal mucosal flaps,1^,2 MeroGel application1^,3 is sufficient to maintain the neo-ostium patent, with almost no need of ostial implants or anti-fibrotic agents. However, this study is very special. All the patients in this study suffered from chronic dacryocystitis with incarceration of a previously implanted nasolacrimal duct stent.4 According to results of the lipiodol dacryocystography and pathological characteristics previously reported, their lacrimal sacs probably became very small. For these cases, fibril tissue proliferation is almost unavoidable due to the serious chronic inflammation infiltration and surgical injury.5–7 The excessive proliferation and subsequent contraction of the fibril tissues around the small neo-ostium may, to a large degree, lead to ostial closure or occlusion.2^,8 Therefore, we implanted a novel lacrimal ostium stent (LOS) developed by us to prevent unwanted ostial closure due to scar contraction.

Different from the traditional silicone tubes or stents, our novel LOS consists of three parts: the central hollow pipe with 6–8 mm in outer diameter and 1–2 mm inner diameter for tear drainage; ellipse positioning plate with 18–20 mm in diameter; and four buckles 1–2 mm in length for fixation4. It was the central hollow pipe with 6–8 mm in outer diameter, not the fan-like positioning plate with 18–20 mm in diameter, which was inserted into the ostium, and the fan-like positioning plate was only placed between the exterior wall of the nasal cavity and the middle turbinate for fixation. As described in our manuscript, it could easily be inserted into the neo-ostium to expand and support the lacrimal flap enough to prevent it from closing4. The authors did not observe that it allowed scar tissue to re-extend and close the ostium, as is your main concern. To further promote wound healing and subsequent epithelization, MeroGel was used to seal the space between the ostial wound and the lacrimal ostium stent.1^,3^,4

We agree that silicone tube/stent intubation can induce or enhance risks of inflammation and granulation, which may be one of the major causes of surgical failure in DCR surgery. When the LOS or the silicone tube remained, 7 of 117 patients (5.98%) in the EE-DCR group underwent isolated removal of significant granuloma causing occlusion of the ostium. However, compared to traditional silicone tube intubation, the implanted LOS did not aggravate further inflammation and granulation. When the LOS or the silicone tube was removed, 73 of 117 patients (62.4%) in the EE-DCR group exhibited scarring and/or granulation tissues of 1–3 mm around the ostium, which was significantly less than the 86.1% of patients (31/36) in the E-DCR group with the same outcome (χ²= 7.114, p = 0.008). At the final review, 64 patients in the EE-DCR group and 19 patients in the E-DCR group had scars and/or granuloma of 1–3 mm around the ostia (p > 0.05), no significant statistical difference existed in the rate of scars, granuloma, and scars with granuloma between the groups (p > 0.05). Of course, we do not know the results if compared to the group without silicone tube intubation. We hope to study it further.

We also appreciate your suggestion that it would have been a more proper approach to first apply additional treatment to alleviate the inflammation following the incarcerated nasolacrimal duct stent removal, and consequently implant the stent as a second step. However, we do not think it is necessary. In this study, before the lacrimal ostial stent was removed, none of the 117 patients complained of epiphora or lacrimal secretions or nasal disorders, and all showed free-flowing lacrimal irrigation from the central hollow pipe of the LOS into the nose. When the lacrimal ostial stent was removed, the ostium remained patent in all patients, only with slight epithelial edema and/or granuloma visible under the endoscope in a small portion of patients.4 Meanwhile, we believe that implanting the LOS after the inflammation was alleviated will not only increase patients’ worries, pain, and burden due to an additional surgery, but also probably lead to some injury to the fragile neo-ostium. Moreover, we could not determine with certainty when the inflammation was completely resolved.

We admit that it is still not ideal and needs further improvement. In this study, in 126 patients (127 eyes), the implanted lacrimal ostial stent was not retained for more than 3 months and detached from 3 patients (3 eyes) after surgery. However, we do not think it corresponds to the difficulty of its stabilization. Once it was implanted to the intra-ostium, we feel that it would seldom move because it was functionally adequate. Before the LOS was removed, none of the 117 patients complained of epiphora or lacrimal secretions, and all showed free-flowing lacrimal irrigation from the central hollow pipe of the LOS into the nose.4 If it had moved, it would probably obstruct the ostium and the patients would have complained of significant epiphora or lacrimal secretions. Even though the LOS could be easily inserted into the small neo-ostium, we agree with you that it would be better and less traumatic to apply the stent through a special injection system as you suggested.

DECLARATION OF INTEREST

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.