Patent ID: 8864774

Claim:
A system for forming an incision in a tympanic membrane and delivering a pressure equalization tube into the incision, the system comprising: (a) a housing including a handle; (b) an elongate shaft assembly coupled with the housing, the shaft assembly comprising: (i) an outer shaft having a blunt distal tip portion, (ii) a cutter linearly moveable within the outer shaft, (iii) a pusher slidably disposed over the cutter within the outer shaft, (iv) a pressure equalization tube slidably disposed about the cutter at a distal end of the pusher, (v) a shield slidably disposed over the pusher and the pressure equalization tube, and (vi) a dilator slidably disposed over the shield, wherein the dilator has an expandable portion, wherein the shield is interposed between the dilator and the pressure equalization tube such that the shield separates the dilator from the pressure equalization tube along a radial dimension; (c) a cam assembly comprising: (i) a cam shaft rotationally coupled within the housing, the cam shaft including a first cam profile, a second cam profile, a third cam profile, and a fourth cam profile; (ii) a first cam follower moveably coupled to the first cam profile, the first cam follower attached to the cutter; (iii) a second cam follower moveably coupled to the second cam profile, the second cam follower attached to the pusher; (iv) a third cam follower moveably coupled to the third cam profile, the third cam follower attached to the shield; (v) a fourth cam follower moveably coupled to the fourth cam profile, the fourth cam follower attached to the dilator; (d) a spring biased between the housing and the cam shaft, the spring having a wound position which places a torsional load on the cam shaft, and a released position; and (e) a release member moveably coupled to the cam shaft, the release member having a first position which maintains the spring in the wound position and a second position which allows the spring to move into the released position; wherein the cam profiles are arranged and configured such that, when the release member is moved into the released position, the spring is released to move the cam shaft and cause the cam followers to linearly move respective portions of the shaft assembly to form an incision in a tympanic membrane using the cutting member, dilate the incision using the dilator, and advance the pressure equalization tube out of the shield and into the incision using the pusher.