Actuation mechanism for use with an ultrasonic surgical instrument

Abstract

An ultrasonic clamp coagulator assembly that is configured to permit selective cutting, coagulation and clamping of tissue during surgical procedures. An elongated portion of the instrument can be configured for endoscopic applications and has an outside diameter of less than 6 mm. The construction includes a clamping mechanism, including a clamp arm pivotally mounted at the distal portion of the instrument, which is specifically configured to create a desired level of tissue clamping forces, exceeding 4 pounds when the trigger is fully closed. The clamping mechanism includes a two-piece pad design and pad material that enables the higher tissue clamping forces and a force-limiting mechanism that effectively smooths out abusive tissue forces. The assembly also features hand activation configured to provide an ergonomical grip and operation for the surgeon. Hand switches are placed in the range of the natural swing of the surgeon's thumb, whether gripping the surgical instrument right-handed or left handed.

Description

REFERENCE TO RELATED APPLICATIONS [0001] The present application claims the priority benefit of U.S. provisional patent application Ser. Nos. 60 / 617,427, filed on Oct. 8, 2004, and 60 / 676,709, filed on May 2, 2005, both of which are incorporated herein by reference. [0002] This application contains subject matter that relates to and incorporates by reference in their entirety, for any and all purposes, the following non-provisional applications: [0003] TISSUE PAD FOR USE WITH AN ULTRASONIC SURGICAL INSTRUMENT, Ser. No. (to be issued), filed Oct. 7, 2005; [0004] COMBINATION TISSUE PAD FOR USE WITH AN ULTRASONIC SURGICAL INSTRUMENT, Ser. No. (to be issued), filed Oct. 7, 2005; [0005] CLAMP MECHANISM FOR USE WITH AN ULTRASONIC SURGICAL INSTRUMENT, Ser. No. (to be issued), filed Oct. 7, 2005; [0006] FEEDBACK MECHANISM FOR USE WITH AN ULTRASONIC SURGICAL INSTRUMENT, Ser. No. (to be issued), filed Oct. 7, 2005; [0007] HANDLE ASSEMBLY HAVING HAND ACTIVATION FOR USE WITH AN ULTRASONIC SURGI...

AI Technical Summary

Benefits of technology

[0025] The clamp coagulator device also includes a force-limiting mechanism that effectively smooths out abusive tissue forces.

Problems solved by technology

Some current ultrasonic shears devices, however, have the tendency to create tissue tags.

Tissue tags may result from insufficient end-effector proximal loading and / or lower proximal blade activity.

This presents certain problems in terms of the pressure profile exerted on the tissue.

Additionally, the fact that blade amplitude decreases moving proximal of the tip of the blade makes the situation worse since the amount of energy transferred to the tissue, even if the pressure was constant, is reduced.

Although these designs have been adequate, they tend to suffer from longevity issues since the pads tend to deteriorate over long surgical procedures.

Additionally, newer designs of clamp coagulator shears increase blade amplitude and / or the loading of the pad against the tissue and blade and overwhelm the pad material, resulting in less than required tissue pad life.

The pad material limits the amount of force that may be applied against the tissue and blade, which in turn limits the tissue thickness or vessel size that some current clamp coagulator shears may effectively cut and coagulate.

During surgical procedures the clamp arm may be subjected to axial clamp forces exceeding 2.5 pounds and / or torsional abuse loads and may cause the clamp arm to disengage from the inner tube or completely from the shears.

In applications with high clamp forces, however, the difference in force attributable to the slope over the possible range of spring compressions becomes very significant and may exceed the maximum force allowable in the blade, in the tube assemblies or in other components of the system.

If this occurs the blade may bend, the actuation mechanism may fail or undesirable tissue effects may occur (i.e. fast cutting, but minimal tissue coagulation).

In some cases, though, the surgeon may, unknowingly, fail to apply the full force of the jaw against the tissue resulting in incomplete tissue cuts or insufficient coagulation.

Alternatively, the surgeon may unknowingly release full force of the jaw against the tissue during a transaction that results in incomplete tissue cuts or insufficient coagulation.

Key drawbacks with this type of instrument activation include the loss of focus on the surgical field while the surgeon searches for the foot pedal, the foot pedal getting in the way of the surgeon's movement during a procedure and surgeon leg fatigue during long cases.

This may be cumbersome, especially for surgeons with large hands.

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