Objectives To identify 'on-table optimal meatal opening size' that predicts post-operative mastoid cavity healing in the canal wall down tympanomastoidectomy. To develop a specific, measurable, achievable, acceptable, replicable and time-bound (SMAART) meatoplasty.Method A double-blind randomised control trial where patients were randomly assigned to standard Portmann 3 flap and new SMAART 2 flap technique.Results There were 18 and 17 participants in the former and latter, respectively. Dry ear was achieved when the on-table ratio of tympanomastoid cavity volume to meatal opening size was 2:1. In a mastoid cavity of 6 ml or less, among the 2 flap patients, the majority had epithelialisation completed by the first month, meatoplasty having significantly shorter duration (12.2 versus 32.3 minutes) and cosmetically better than 3 flap.Conclusion Optimal meatoplasty is when tympanomastoid cavity volume ratio to meatal opening size is 2:1. When the on-table mastoid cavity is either 6 ml and less or is obliterated to 6 ml and less, the new SMAART 2 flap meatoplasty should be considered.