Surgical cutting accessory with nickel titanium alloy cutting head

#This invention relates generally to a surgical cutting accessory that is used to cut tissue and, more particularly, to a surgical cutting accessory with a nickel titanium alloy cutting head.

#One component that is an integral part of many surgical tool systems is the cutting accessory. This cutting accessory is a device that is typically attached to some sort of driving unit. Often, but not always, the driving unit is some type of handpiece that contains an electrically or pneumatically driven motor. The cutting accessory is an elongated member that extends from the handpiece. The distal end of the cutting accessory, the end furthest from the surgeon, is shaped to define a cutting head. In order to remove tissue, the surgeon actuates the handpiece and applies the cutting head of the accessory to the tissue to be removed. If the tissue being cut is bone, the cutting head is used to form a bore in the bone or to otherwise shape the bone.

#Often cutting accessories are fabricated from stainless steel. Advantages of making an accessory out of this material are that it is relatively economical to provide, the steel can be shaped to define the sharp cutting surfaces of the head, and it can also withstand the rigors of post manufacture sterilization without physical degradation.

#The invention is pointed out with particularity in the claims. The above, and further features and advantages of the invention, are understood by reference to the drawings in which:

#FIG. 1 is a plan and partially cutaway view of a surgical cutting accessory of this invention;

#FIG. 2A is an exploded view of a cutting accessory;

#FIGS. 1, 2A and 2B illustrate one surgical cutting accessory 20 of this invention. The particular accessory is a subchondral drill used to cut holes in bone that is surrounded by soft tissue. This particular type of drill is designed for use in an endoscopic surgical procedure in which its elongated body is inserted into a portal formed in the body of the patient. It should be understood that other cutting accessories are designed to perform other types of surgical procedures, including non-endoscopic, open cut procedures.

#The depicted cutting accessory 20 has an outer tube 22 that, in this version of the cutting accessory, is sometimes referred to as a retractable housing. The proximal end of the outer tube 22, the end opposite the distal end, is coupled to an outer hub assembly 24. The outer hub assembly 24 is used to releasably hold the cutting accessory 20 to the handpiece with which it is used, (handpiece not illustrated). One such handpiece is sold by the Applicants' Assignee under the trademark TPS 12K Shaver. Located within, and extending axially through outer tube 22 and outer hub assembly 24, is a tubular drive shaft 26. An inner hub 28 is attached to the proximal end of the drive shaft that extends out of the outer hub assembly 24. The inner hub assembly is shaped to releasably engage with a motor coupling that is connected to the motor drive shaft that is part of the handpiece with which the cutting accessory 20 is used. This inner hub 28 is coupled to the handpiece so as to transfer the rotational movement of the handpiece drive shaft to the accessory drive shaft 26. It should, of course, be recognized that this rotational movement may not, at all times, be unidirectional. Some cutting accessories, in some or all surgical procedures, are driven in an oscillatory movement pattern by the complementary handpiece in order to perform the desired surgical procedure.

#A head 30 is attached to the distal end of the drive shaft 26. Head 30 is the portion of the cutting accessory 20 that performs the tissue removal function.