Endoscopic endonasal dacryocystorhinostomy (EEDCR), which was first described in the late 1980s , has gained considerable popularity in the recent two decades with the advent of the rigid fiber-optic endoscope and its use in paranasal sinus surgery. It avoids a facial incision, disruption of the medial canthal tendon, injury to the terminal branch of facial nerve, or a full thickness (skin to mucosa) ring contracture over the osteotomy site, all of which may lead to secondary lacrimal pump failure despite anatomical patency. Endoscopic DCR is not contraindicated during active dacryocystitis (minimal risk of fistula formation), presumably allowing faster healing process, and is perceivably less traumatic compared to external DCR. Recent published series of EEDCR reported higher success rates up to 95 % as compared to prior studies . This likely reflects an increased experience with endoscopic instrumentation and anatomy among lacrimal surgeons and an improved understanding and control of postoperative mucosal healing . The key to successful EEDCR relies on atraumatic creation of a large osteotomy  with adequate superior bony clearance, complete marsupialization of the lacrimal sac , maximal preservation of the nasal and lacrimal sac mucosa with close approximation of the mucosal edges [2, 5], as well as regular endoscopic monitoring of ostial healing during the early postoperative period.
Davies MJ, Lee S, Lemke S, et al. Predictors of anatomical patency following primary endonasal dacryocystorhinostomy: a pilot study. Orbit. 2011;30:49–53.PubMedCrossRefGoogle Scholar
Codere F, Denton P, Corona J. Endonasal dacryocystorhinostomy: a modified technique with preservation of the nasal and lacrimal mucosa. Ophthal Plast Reconstr Surg. 2010;26:161–4.PubMedCrossRefGoogle Scholar
Wormald PJ, Kew J, Van Hasselt CA. The intranasal anatomy of the nasolacrimal sac in endoscopic dacryocystorhinostomy. Otolaryngol Head Neck Surg. 2000;123:307–10.PubMedCrossRefGoogle Scholar
Caversaccio M, Hausler R. Insertion of double bicanalicular silicone tubes after endonasal dacryocystorhinostomy in lacrimal canalicular stenosis: a 10-year experience. ORL J Otorhinolaryngol Relat Spec. 2006;68:266–9.PubMedCrossRefGoogle Scholar
Chong KK, Lai FH, Ho M, Luk A, Wong BW, Young A. Randomized trial on silicone Intubation in endoscopic mechanical dacryocystorhinostomy (SEND) for primary nasolacrimal duct obstruction. Ophthalmology. 2013;120:2139–45.PubMedCrossRefGoogle Scholar
Ali MJ, Mariappan I, Maddileti S, et al. Mitomycin C in dacryocystorhinostomy: the search for the right concentration and duration – a fundamental study on human nasal mucosal fibroblasts. Ophthal Plast Reconstr Surg. 2013;29:469–74.PubMedCrossRefGoogle Scholar
Huang J, Malek J, Chin D, et al. Systematic review and meta-analysis on outcomes for endoscopic versus external dacryocystorhinostomy. Orbit. 2014;33:81–90.PubMedCrossRefGoogle Scholar