Background
In 1998, Eavey first introduced butterfly graft myringoplasty for small central perforations1. The two main challenges are evaluation of perforation size and preparation of an appropriately fitting graft2. 

Objectives
We aim to introduce a simple technique for measuring perforation size. 

Method
Following local anaesthetic infiltration into the tragus, the perforation is freshened and measured with a 2mm Rosen round knife (Image 1&2). 

Tragal incision is made and a skin punch 2mm larger than the estimated perforation size is used to harvest the graft. The graft is prepared by creating a 1mm deep groove circumferentially with an 11-sized blade (Image 3). 

The groove of the graft is engaged with the anterior rim of perforation and manipulated until the perforation edges fit into the entire groove (Image 4). 

Conclusion  
Measuring perforation size with a Rosen round knife is simple and quick and provides a good size estimate for butterfly grafts.

A novel technique for measuring tympanic membrane perforation size in butterfly graft myringoplasty