Tympanostomy tube delivery device with replaceable shaft portion

Abstract

A tympanostomy tube delivery device comprises a shaft assembly and a handpiece. All or a portion of the shaft assembly is selectively coupleable and removable from the handpiece. The handpiece includes a housing defining an opening that can receive a portion of the shaft assembly. The shaft assembly comprises a cannula, a piercer/dilator tube, a shield tube, and a pusher tube operable to translate relative to the cannula. The pressure equalization tube is positioned within the shield tube of the shaft assembly. The piercer/dilator tube and the shield tube are operable to pierce the tympanic membrane and dilate an opening formed therein. The pusher tube is operable to drive the pressure equalization tube out of the shield tube of the shaft assembly and into the opening formed in the tympanic membrane. Upon completion of the procedure, all or a portion of the shaft assembly may then be removed and replaced.

I/we claim: 
     
         1 .- 20 . (canceled) 
     
     
         21 . A shaft assembly for a tympanostomy tube delivery device, the shaft assembly comprising:
 a shield tube defining a proximal end, a distal end, and a longitudinal central axis;   a first cam follower rigidly coupled to the proximal end of the shield tube;   a pusher tube defining a proximal end and a distal end, the pusher tube coaxially disposed within the shield tube;   a second cam follower rigidly coupled to the proximal end of the pusher tube;   a tympanostomy tube disposed within the shield tube, the distal end of the pusher tube abutting a proximal end of the tympanostomy tube, and the tympanostomy tube having a length measured along the longitudinal central axis; and   the first cam follower and the second cam follower separated by a distance greater than the length of the tympanostomy tube.   
     
     
         22 . The shaft assembly of  claim 21  further comprising:
 a cannula defining a proximal end and a distal end; 
 a dilator tube defining a proximal end and a distal end, the dilator tube coaxially disposed within the cannula; 
 a third cam follower rigidly coupled to the proximal end of the dilator tube; 
 the shield tube, the pusher tube, and the tympanostomy tube coaxially disposed within the dilator tube. 
 
     
     
         23 . The shaft assembly of  claim 22  wherein the dilator tube is further configured to both cut and dilate a tympanic membrane. 
     
     
         24 . The shaft assembly of  claim 22  wherein the dilator tube further comprises:
 a first flexible leaf on the distal end of the dilator tube; 
 a second flexible leaf on the distal end of the dilator tube; 
 a piercer tip on the distal end of the first flexible leaf, the piercer tip configured to pierce a tympanic membrane. 
 
     
     
         25 . The shaft assembly of  claim 22  wherein the cannula further comprises an annular flange on an outside surface of the cannula. 
     
     
         26 . The shaft assembly of  claim 22  further comprising the pusher tube is configured to translate along the longitudinal central axis relative to the shield tube, the shield tube is configured to translate along the longitudinal central axis relative to the dilator tube, and the dilator tube is configured to translate along the longitudinal central axis relative to the cannula. 
     
     
         27 . The shaft assembly of  claim 22  further comprising at least one component configured to maintain a distance between the first cam follower, the second cam follower, and the third cam follower. 
     
     
         28 . The shaft assembly of  claim 22  further comprising the first cam follower and the third cam follower separated by a distance greater than the length of the tympanostomy tube. 
     
     
         29 . The shaft assembly of  claim 21  wherein the tympanostomy tube is radially compressed with the shield tube. 
     
     
         30 . The shaft assembly of  claim 21  wherein the first cam follower further comprises:
 a first flange member extending laterally in a first direction; 
 a second flange member extending laterally in a second direction opposite the first direction, and the first and second flange members define a plane parallel to the longitudinal central axis; 
 each of the first and second cam followers includes an annular flange. 
 
     
     
         31 . The shaft assembly of  claim 30  wherein the first cam follower further comprises a pin extending from a first side of the first and second flange members, first side opposite a second side of the first and second flange members at which the proximal end of the shield tube couples to the first and second flange members. 
     
     
         32 . The shaft assembly of  claim 21  wherein the pusher tube is configured to translate along the longitudinal central axis relative to the shield tube. 
     
     
         33 . The shaft assembly of  claim 21  further comprising at least one component configured to maintain a distance between the first cam follower and the second cam follower. 
     
     
         34 . A shaft assembly for a tympanostomy tube delivery device, the shaft assembly comprising:
 a cannula defining a proximal end, a distal end, and a longitudinal central axis;   a dilator tube defining a proximal end and a distal end, the dilator tube coaxially disposed within the cannula;   a dilator cam follower rigidly coupled to the proximal end of the dilator tube;   a shield tube defining a proximal end and a distal end, the shield tube coaxially disposed within the dilator tube;   a shield cam follower rigidly coupled to the proximal end of the shield tube;   a pusher tube defining a proximal end and a distal end, the pusher tube coaxially disposed within the shield tube;   a pusher cam follower rigidly coupled to the proximal end of the pusher tube;   a tympanostomy tube disposed within the shield tube, the distal end of the pusher tube abutting a proximal end of the tympanostomy tube, and the tympanostomy tube having a length measured along the longitudinal central axis.   
     
     
         35 . The shaft assembly of  claim 34  further comprising the pusher cam follower and the shield cam follower separated by a distance greater than the length of the tympanostomy tube. 
     
     
         36 . The shaft assembly of  claim 34  further comprising the shield cam follower and the dilator cam follower separated by a distance greater than the length of the tympanostomy tube. 
     
     
         37 . The shaft assembly of  claim 34  wherein the dilator tube is further configured to both cut and dilate a tympanic membrane. 
     
     
         38 . The shaft assembly of  claim 34  wherein the dilator tube further comprises:
 a first flexible leaf on the distal end of the dilator tube; 
 a second flexible leaf on the distal end of the dilator tube; and 
 a piercer tip on the distal end of the first flexible leaf, the piercer tip configured to pierce a tympanic membrane. 
 
     
     
         39 . The shaft assembly of  claim 34  further comprising the pusher tube is configured to translate along the longitudinal central axis relative to the shield tube, the shield tube is configured to translate along the longitudinal central axis relative to the dilator tube, and the dilator tube is configured to translate along the longitudinal central axis relative to the cannula. 
     
     
         40 . The shaft assembly of  claim 34  wherein the tympanostomy tube is radially compressed with the shield tube.