The instruments* described here are designed to incise the skin of the bony external auditory meatus when creating the tympanometal flap for transtympanic surgical procedures. The wheels are 3 mm. in diameter, have a sharp cutting margin, and when they are rolled firmly against the bony wall, they cut through the skin and periosteum without tearing the skin. The wheel should be rolled two or three times in the same line of incision. One wheel is parallel and the other at right angles to the shaft. Ordinarily 50 to 100 operations can be performed with a set of knives without sharpening.
Henry Ford Hospital (2).
Roller knives