ChiCTR‐INR‐16008616.

Trial name or title	Mitomycin, Intubation vs No adjuvant In MUcosal‐preserving Mechanical endonasal dacryocystorhinostomy for primary acquired nasolacrimal duct obstruction (MINIMUM endonasal DCR for PANLDO)
Methods	Randomized parallel‐group design
Participants	Inclusion criteria: 340 adults ≥ 18 years old and there is no maximum age limit; primary acquired nasolacrimal duct obstruction (PANLDO) diagnosed by lacrimal irrigation and probing, confirmed intraoperatively after incision of lacrimal sac; informed consent for operation, randomization, and recording; compliance to follow‐up and treatment Exclusion criteria: pregnancy, lactation, allergy to mitomycin, cocaine, adrenaline, steroid, silicone material; contraindications of endonasal DCR or inability to undergo nasal endoscopy; acute (< 3 months) or non‐bacterial dacryocystitis, e.g. tuberculosis, fungal, or parasitic; ipsilateral canalicular disorder, e.g. obstruction, canaliculitis, canaliculocele, diverticulum; ipsilateral recurrent NLDO or any prior lacrimal intervention except punctoplasty; ipsilateral facial paralysis despite apparent clinical recovery; ipsilateral conditions affecting bony nasolacrimal outflow, e.g. midfacial trauma/fracture, osteoma, fibrous dysplasia and other skull‐base disorders; ipsilateral suspected or confirmed nasolacrimal or sino‐orbital neoplasm; ipsilateral severe ocular surface disorders, e.g. ocular cicatricial pemphigoid, chemical burns, Steven Johnson syndrome, toxic epidermal necrolysis; conditions affecting mucosa of the nose or nasolacrimal system, e.g. rhinosinusitis, Wegener’s granulomatosis, sarcoidosis, radioactive iodide, head and neck radiotherapy, ipsilateral maxillectomy, systemic chemotherapy (5‐fluorouracil, docetaxel); ipsilateral topical antiglaucomatous or chemotherapy drops (e.g. timolol, mitomycin C); intraoperative false passage of Bowman probe or metal part of silicone stent; dacryolith or intrasaccular mass
Interventions	Intervention: topical mitomycin C Comparison intervention: normal saline
Outcomes	Primary outcome: anatomical patency, functional patency, ostium morphologies, additional procedure(s), and trial‐related complication(s) Secondary outcome: preoperative (demographic), intraoperative (endonasal, lacrimal sac), and postoperative (ostial) features associated with poor outcomes Maximum follow‐up: 12 months
Starting date	Not reported Estimated end date: not reported
Contact information	www.chictr.org.cn/showprojen.aspx?proj=14599
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