Surgery – Instruments – Cutting – puncturing or piercing
Reexamination Certificate
1997-07-25
2001-07-03
Thaler, Michael H. (Department: 3731)
Surgery
Instruments
Cutting, puncturing or piercing
Reexamination Certificate
active
06254622
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ultrasonically driven surgical blade.
2. Description of Related Art
Ultrasonic knives are commonly used to cut and coagulate tissue. An ultrasonic knife assembly includes a blade that is coupled to an ultrasonic horn. The horn contains a transducer that is excited by an electrical source. The excitation of the transducer induces a corresponding vibratory movement of the blade. It has been found that the vibratory movement of the blade can increase the cutting and/or coagulation of tissue. Generally speaking, a sharp blade will increase the cutting efficiency of the knife, while a dull blade has been found to improve hemostasis.
U.S. Pat. No. 5,324,299 issued to Davison et al. discloses an ultrasonic blade which has a hook. The hook has a sharpened blade recess which terminates into a dull tip. The dull tip tends to grab and pull the patient tissue into tension, so that the sharp blade portion can more readily cut the tissue. Although potentially effective in cutting unsupported fatty tissue, the Davison blade would be relatively ineffective in cutting non-hydrogenous tissue.
U.S. Pat. No. 3,086,288 issued to Balamuth et al., discloses an arcuate shaped surgical blade which has a cutting surface that extends from the base of the blade to the blade tip. Although potentially efficient in cutting tissue, the sharpness of the entire blade works against coagulation. Additionally, the wide profile of the Balamuth blade does not allow the knife to be inserted into a trocar, thereby limiting the use of the blade in laparoscopic procedures. It would be desirable to provide a low profile ultrasonically driven blade that is efficient in both cutting and coagulating tissue, and has a profile that allows the knife to be inserted through a trocar.
SUMMARY OF THE INVENTION
The present invention is an ultrasonically driven surgical blade which has a recessed cutting portion that extends to a pointed tip. The interface between the tip and the recessed cutting portion provides a cutting edge which has a relatively low attack angle. The recessed cutting portion is located on only one side of the blade to create an unsymmetrical cutting action. When the surgical blade is ultrasonically driven, the unsymmetrical cutting surface and the offset center of gravity creates a transverse movement of the blade. The transverse movement of the blade more efficiently transfers the ultrasonic energy to the tissue to increase tissue coagulation. The blade may be driven by an acoustic wave that has a first base frequency that is modulated by, or switched with, a second frequency to further improve hemostasis. The blade may be coupled to a horn by a sleeve that contains electro-cautery pins, and/or lumens that provide gas for an argon plasma, or a pressure or vacuum source. The profile of the blade tip is no larger than the profile of the blade body so that the blade can be easily inserted into an instrument such as a trocar sleeve.
REFERENCES:
patent: 3086288 (1963-04-01), Balamuth et al.
patent: 4931047 (1990-06-01), Broadwin et al.
patent: 5176677 (1993-01-01), Wuchinich
patent: 5207675 (1993-05-01), Canady
patent: 5261922 (1993-11-01), Hood
patent: 5281216 (1994-01-01), Klicer
patent: 5324299 (1994-06-01), Davison et al.
patent: 5391144 (1995-02-01), Sakurai et al.
patent: 5562610 (1996-10-01), Brumbach
patent: 014708 (1993-08-01), None
Irell & Manella, LLP.
Thaler Michael H.
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