Angled rotary tissue cutting instrument and method of fabricating the same

Abstract

The present invention is generally characterized in an angled rotary tissue cutting instrument including an outer blade assembly, having a rigid tubular member with proximal and distal portions connected by a bead, and an inner blade assembly rotatably disposed within the outer blade assembly and including a tubular drive shaft at a proximal end, a cutting tip at a distal end, and a flexible coupling disposed between the drive shaft and the cutting tip. The drive shaft and cutting tip include neck portions which are disposed telescopically within proximal and distal ends of the coupling. The flexible coupling is formed of a flexible polymeric material, and each of the neck portions includes a lateral opening defining a predetermined flow path for the polymeric material during fabrication so that the flexible polymeric coupling includes flow portions extending into the openings in the neck portions of the drive shaft and the cutting tip to form permanent, interlocking mechanical joints therewith capable of receiving and transmitting torque.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates generally to surgical cutting instruments and, more particularly, to surgical cutting instruments having an elongate inner member rotatably disposed within an elongate outer tubular member having a cutting window at a distal end which cooperates with or permits the inner member to cut or abrade bodily tissue.2. Discussion of the Related ArtSurgical cutting instruments in which an elongate inner member is rotated within an elongate outer tubular member have become well accepted in surgical procedures where access to the surgical site is gained via a narrow portal or passage. Typically, the outer tubular member includes a distal end with an opening for defining a cutting port or window and the inner member includes a distal end with a cutting tip for engaging bodily tissue via the opening. Proximal ends of the inner and outer members are commonly secured to hubs which attach to a handpiece having a motor...

AI Technical Summary

Benefits of technology

Accordingly, it is a primary object of the subject invention to overcome the abovementioned disadvantages of the prior art and to improve angled rotary tissue cutting instruments by providing a rotary tissue cutting instrument capable of operating over an increased range of bend angles while at the same time reducing the radius of curvature of the bend for use in head and neck surgery and other parts of the body.

Some of the advantages of the present invention over the prior art are that permanent, interlocking joints can be formed between a flexible coupling and other rotating components of an inner blade member in a rotary cutting instrument without the use of adhesives or pins, that a wider range of manufacturing tolerances and clearances can be accommodated when forming such joints, that torsional forces can be more efficiently transmitted while allowing the coupling to bend, that preloading of the coupling is not required to transmit torsional forces, and that fluid leakage through the inner blade member is minimized.

Problems solved by technology

Variable-angle rotary tissue cutting instruments, such as that described in U.S. Pat. Nos. 5,411,514 and 5,601,586 to Fucci et al, permit the user to bend the outer tube to a user-selected angle while still enabling the inner tube to be selectively inserted into and removed from the outer tube; however, known fixed-angle and variable-angle rotary tissue cutting instruments typically have a bend with a radius of curvature on the order of about 2 to 4 inches and are typically not capable of being bent beyond 15.degree..

While the relatively small bend angle and relatively large radius of curvature of these angled tissue cutting instruments is generally suitable for most types of arthroscopic surgery, such instruments are of little use in certain types of head and neck surgery because they are not able to access surgical sites such as the maxillary sinus area which is normally accessed with hand instruments such as ball elevators and suction probes having bend angles of about 40.degree. and radii of curvature of the order of 1.5 inches or less.

One disadvantage of known flexible couplings is their inability to transmit sufficient torque at high speeds through angles much greater than 15.degree. and bend radii less than 2.0 inches.

In the case of flexible couplings in the form of coiled springs, there is also the possibility that gaps will develop between the coils as the coupling bends thereby resulting in a decrease of vacuum through the lumen of the inner member and a diminution of the ability of the instrument to aspirate loose tissue through the lumen.

Another disadvantage associated with the use of a coiled springs as flexible couplings is the tendency of such members to require tightening or preloading when torque is applied before they are capable of transmitting the torque to the cutting tip.

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