Penttilä 2011.

Methods	Study design: randomized controlled trial, parallel group Unit of analysis: eyes Number randomized: 30 in total, 15 per group Number of arms: 2 Enrollment start year: 2004 Length of follow‐up: 6 months Sample size calculations: not reported Losses to follow‐up: 2 (6.25%) lost to follow‐up (reasons and groups not reported)
Participants	Country: Finland Age (mean (SD)): 65 (11) in the MMC group, 70 (10) in the EN‐DCR only group Females (n (%)): 27 (90) in total, 13 (86.7) in the MMC group, 14 (93.3) in the EN‐DCR only group Inclusion criteria: aged 18 years, American Society of Anesthesiologist physical status was I‐III, scheduled for revision lacrimal pathway surgery due to tearing or recurrent infection after failed EX‐DCR or EN‐DCR Exclusion criteria: presaccal obstruction; malignancy in the paranasal sinuses, nasal cavity, or lacrimal pathway; mental disability; pregnancy; breastfeeding Study group differences: not significant
Interventions	Intervention: EN‐DCR with application of 0.4 mg/mL MMC Comparison intervention: EN‐DCR alone
Outcomes	Measured outcomes: functional success, defined as the relief of epiphora anatomic success, defined as patency to lacrimal irrigation ocular symptom score Nasolacrimal Duct Obstruction Symptom Score Adverse events: additional surgery for abnormalities
Identification	Author name: Elina Penttila Institution: Department of Otorhinolaryngology at Kuopio University Hospital Email: grigori.smirnov@kuh.fi
Notes	Funding source: not reported Declarations of interest: none Trial registration number: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"The allocation was computer‐generated and a sealed opaque envelope method was used to ensure blinding."
Allocation concealment (selection bias)	Low risk	"The allocation was computer‐generated and a sealed opaque envelope method was used to ensure blinding."
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Masking of participants and personnel was not reported.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Masking of outcome assessors was not reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Intention‐to‐treat analysis was not followed: 2/32 (6.25%) participants were withdrawn and not included in the final analysis, however we determined that this was unlikely to have impacted on the results.
Selective reporting (reporting bias)	Unclear risk	No trial or protocol registration available for comparison to ascertain selective outcome reporting.
Other bias	Unclear risk	There was insufficient information to permit a judgement of 'low risk' or 'high risk'.