Human Lacrimal Drainage System Reconstruction, Recanalization, and Regeneration

Purpose: This review examines the broad contexts of the reconstructive and recanalization strategies of the human lacrimal drainage system.Materials and methods: A PubMed search was performed using individually and combination of the terms "lacrimal," "reconstruction", "recanalization," "canaliculus," "canalicular," "stenosis," "obstruction," "block," "drainage," "disorder," "disease," "nasolacrimal duct (NLD)," "endoscopy," "dacryoendoscopy," "trauma," "laceration," "stents," "repair," "tubes," "tear," "eyelid," "Sisler," "trephine," and "trephination". Selections from these lists were the basis of examination of reconstruction and recanalization strategies of multiple lacrimal disorders and their outcomes.Results: The major focus areas of this review are obstructions of the canaliculi and the NLD, traumatic involvement of the lacrimal drainage and their reconstruction strategies, and dacryoendoscopy-guided recanalization of the NLDs. The review found evidence for lack of uniformity in accurately defining the concepts of lacrimal drainage stenosis, partial or complete obstructions. Canalicular obstructions are difficult to manage and outcomes depend on the location of the obstruction. High success rates were reported in cases of canalicular lacerations managed by repair and silicone intubation. Controversies exists in the recanalization strategies involving the NLD. In the absence of any current regenerative strategies, NLD recanalization appears to be promising, but skepticism is well justified until its long-term effects are well known.Conclusions: Reconstructive strategies in canalicular trauma are highly successful. Recanalization strategies for the lacrimal drainage system are promising and there is a need to explore stem cells and regenerative modalities to take the lacrimal drainage science a step forward.