Objective: The present study was aimed to systematically explore how modifications to the original endoscopic dacryocystorhinostomy (DCR) contributed to the success or failure of the outcome.

Materials and Methods: Procedure and clinical outcome data in the Thai endoscopic dacryocystorhinostomy (TED) Collaborative were analyzed and compared with various modified endoscopic DCR techniques identified from published literatures. Main outcome measures were improved symptom of tearing, free flow of lacrimal sac irrigation, and ostium patency. The three periods of surgical technique modifications were 2004 to 2005, 2006 to 2007, and 2008 to 2015. The detailed steps of the present study approaches are described and comparatively discussed with the approaches used by the others.

Results: TED data contained 729 operations (primary NLDO 89.30%) performed in 537 patients (male 17.88%, age 58.29 years) at three sites between 2004 and 2015. Overall success rate was 92.04%. Primary DCR had significantly better success than revision DCR (93.55% versus 79.49%, p<0.001). Between 2004 and 2005, the conventional antero-posterior flap without suturing was performed in 150 operations with unsatisfactory outcomes. The success rate increased from 81.33% to 88.52% for 270 operations performed between 2006 and 2007. This is mainly because of the adequate bone removal, assessed by using the “45-degree” test, and partly because of the supero-inferior flap with suturing that was introduced in selected cases. Additionally, the suturing was added to the anterio-posterior flap technique. The suturing was aimed to promote primary intention healing. The success rate dramatically increased in the 309 operations performed between 2008 and 2015 because of appropriate selection of flap creation and suturing technique in addition to the use of the “45-degree” test to ensure adequate bone removal.

Conclusion: The improvement of endoscopic DCR outcomes has been contributed by at least two key modifications to the original technique, which are adequate bone removal assessed by using the “45-degree” test and primary intention healing using flap creation and suturing.

Keywords: Dacryocystorhinostomy, 45-Degree test, Nasolacrimal duct obstruction

Received 15 Mar 2019 | Revised 6 Jun 2019 | Accepted 7 Jun 2019