The role of lacrimal stent in endoscopic dacryocystorhinostomy

Abstract

Dear Editor, We are grateful to the questioner for the comments on our manuscript [1]. The correspondent’s first question was about the size of bone resection during endoscopic dacryocystorhinostomy (DCR). I agree that complete bone resection exposing the full length of the lacrimal sac is one of the most important parts affecting the surgical result. The boundaries of complete bone resection are inferiorly from the level of the inferior turbinate, superiorly to the level of the fundus (the level common canaliculus joining to the lacrimal sac), and anteriorly and posteriorly the edge of the lacrimal sac. The bone covering the posterior part of the lacrimal sac is lacrimal bone, which is thin and can be easily fractured and removed with an elevator. The anterior part is the frontal process of the maxilla. After removal of lacrimal bone, we use a rongeur (Koros Osteo-Punch Rongeurs , 2 mm, T. Koros Surgical Instruments Corp., CA, USA) engaging and removing the free edge of the frontal process of the maxilla. However, sometimes there is a limitation in resection of the superior part with the rongeur; then, a diamond DCR bur (High Speed Diamond DCR Bur , 2.5 mm, 20 curved, Medtronic Xomed, Inc., FL, USA) is introduced. The questioner has mentioned articles [2,3] recommending creation of a 15–20 mm antero-posterior diameter osteotomy. Because we do not perform postoperative computed tomography (CT) scans, we have no data on how large we make bone resections in length, but we estimate that it is around 10 mm antero-posteriorly. The articles the questioner has mentioned were based on external DCR, not endoscopic DCR. In endoscopic DCR, because the bone work is performed under direct visualization of the lacrimal sac from the nose, the appropriate amount of bone resection is possible and it is not same for everyone. Several previous articles on endoscopic DCR showed excellent success rates without mentioning such a large size of bone resection, 15–20 mm [4–6]. The second comment was on our surgical results. In the common canalicular obstruction group of our series, the success rate of the no stent group was 57.1%, compared with 84.5% in the stent group. Even though there was no statistical significance, we concluded that the silicone stent group seems to have a higher success rate. Just like the questioner said, the statistical significance would have been reached with a greater sample size. Although there was no statistical significance, we thought that the silicone stent seems to have a beneficial role in common canalicular obstruction. However, we agree with the questioner’s point and have no further comments on this matter. The third criticism concerned the assessment of the surgical outcome. Surgery was considered successful if the patients had marked improvement of preoperative chronic epiphora and endoscopic findings revealing a patent rhinostomy on nasal endoscopy. We used a visual analog scoring system, 0 to 10. Zero stands for no symptom and 10 for the most severe symptom. Every enrolled patient’s preoperative score was more than 5, and ‘marked improvement’ was considered if the score was 2 or less. An objective method like a flow test of fluorescein from the conjunctiva to the nose could have made this study more perfect. However, we still think that the patients’ symptom improvement is the most important part. Again, we thank the questioner for the interest in our manuscript.