Trocar

Details Trocar Trocar

1993-09-15

2001-03-06

Thaler, Michael H. (Department: 3731)

Surgery

Instruments

Cutting, puncturing or piercing

C604S164120

Reexamination Certificate

active

06197041

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a surgical instrument for piercing or puncturing a wall of body tissue to provide communication with the inside of an anatomical cavity, and more particularly this invention relates to a powered trocar with an optional safety feature for preventing the unintended puncturing of body tissue.
2. Background of the Art
Many medical procedures gain access to the inside of an anatomical cavity by using an implement such as a trocar, cannula or needle having a sharpened point to pierce or puncture the bodily tissues, muscles and membranes forming the cavity wall. A surgical needle, for example, connected to a catheter may be used to pierce a cavity (blood vessel, subarachnoid space, heart ventricle). After piercing the cavity, the needle is left in situ and used to inject or withdraw gaseous or liquid phase fluids from the cavity. similarly, in several endoscopic procedures, a small incision may be made in the skin of a patient along the abdomen for example, and the sharp point of a larger penetrating implement such as a trocar of suitable length and diameter is inserted into the incision, and pushed until the point punctures the cavity wall. Then, a sleeve follows the implement into the puncture wound to preserve the shape of the passageway created by the implement. After the sleeve is in place, the implement may be withdrawn and an endoscope and operating instruments may be inserted via the sleeve to view and operate upon organs within the cavity. Endoscopic instruments are those instruments having a relatively narrow and elongated portion for use in endoscopic surgical procedures wherein such instruments create or are inserted through a small diameter puncture in order to carry out surgical procedures within a human or animal body.
Penetrating the wall of an anatomical cavity with a surgical puncturing instrument can be quickly done and, usually creates a small neat passageway providing communication to the interior of the cavity. While the sharp point of a penetrating implement is being pushed through a cavity wall, it encounters great resistance from the tissue, muscle and membranes forming the cavity wall. Once the sharp point and blade of the implement pass through the cavity wall and into the cavity, the resistance drops significantly. The sharp point of the implement, however, can easily injure organ structure within the cavity upon the slightest contact. Unless a surgeon stops pushing the implement just as soon as penetration is complete, there is a risk that the implement will continue penetrating deeply into the cavity and injure neighboring organ structure. If an unintended bodily member is injured by the point of the implement, there is a risk that the injury may not become apparent until after completion of the surgery. At a minimum, such an injury will delay a patient's recovery. Severe injuries of this type may endanger the patient's health, and corrective surgery may be required.
Various instruments have been developed to deal with this problem. For example, U.S. Pat. No. 4,601,710 discloses a surgical instrument having a spring biased movable shield which retracts into a cannula to expose the sharp trocar tip when pressed against body tissue, but which moves forward to protect body tissue from contact with the trocar tip when the instrument has passed through the wall of body tissue.
While the instrument described in U.S. Pat. No. 4,601,710 provides an added degree of safety as opposed to an instrument without a shield, the aforementioned problem remains: the sudden drop in the resistance to the trocar blade when penetration has been made into the body cavity increases the chance of uncontrolled continued penetration and possible damage to the underlying body tissue. Moreover, tissue trauma may result from the shield. To alleviate this problem a powered trocar has been developed.
SUMMARY OF THE INVENTION
Presented herein is a pneumatically powered trocar assembly which includes a source of compressed gas which releases a metered amount of gas to chamber. A piston slidably positioned within the chamber is driven forward by the compressed gas introduced therein, and an obturator with a tissue piercing tip are advanced thereby. Optionally, a sensor detects the presence of body tissue within the cutting path of the tip and blocks the passage of compressed gas to the chamber, or alternatively, opens an escape vent to release compressed gas therefrom if insufficient body tissue resistance is encountered.
More particularly, the powered trocar assembly of the present invention includes a frame, a tissue piercing tip, drive means housed by the frame for advancing the tissue piercing tip in response to the application of pneumatic power, trigger means for releasing a predetermined quantity of compressed gas from a source thereof, and means for communicating said quantity of compressed gas to a chamber. The drive means includes a piston movable within said chamber in response to the entry or egress of compressed gas therein, and an obturator shaft mounted to said piston, the tissue piercing tip being mounted to the distal end of said obturator shaft.
The obturator may alternatively be fixedly mounted to the piston, or slidably mounted thereto. The apparatus may optionally include sensing means projecting distally beyond the cutting tip and movable proximally against a distal biasing force to indicate the presence of body tissue in the cutting path of the trocar tip. In another alternative the cutting tip serves as the sensing means by causing the release of compressed gas from the chamber if insufficient tissue resistance is encountered.
Activation of the apparatus, which places it in a ready to fire condition, may be accomplished by actuation of the tissue sensing means, or by assembling and firmly holding together the powered trocar with a cannula assembly.


REFERENCES:
patent: 1147408 (1915-07-01), Kells
patent: 1213001 (1917-01-01), Philips
patent: 2097039 (1937-10-01), Peterson
patent: 2525329 (1950-10-01), Wyzenbeek
patent: 3030959 (1962-04-01), Grünert
patent: 3561429 (1971-02-01), Jewett
patent: 3643649 (1972-02-01), Amato
patent: 3727613 (1973-04-01), Sorenson et al.
patent: 3752161 (1973-08-01), Bent
patent: 3762416 (1973-10-01), Moss et al.
patent: 3789752 (1974-02-01), Kim et al.
patent: 3882849 (1975-05-01), Jamshidi
patent: 3948271 (1976-04-01), Akiyama
patent: 3994287 (1976-11-01), Turp et al.
patent: 4013080 (1977-03-01), Froning
patent: 4177814 (1979-12-01), Knepshield et al.
patent: 4191191 (1980-03-01), Auburn
patent: 4230123 (1980-10-01), Hawkins, Jr.
patent: 4254762 (1981-03-01), Yoon
patent: 4299230 (1981-11-01), Kubota
patent: 4356826 (1982-11-01), Kubota
patent: 4375815 (1983-03-01), Burns
patent: 4393587 (1983-07-01), Kloosterman
patent: 4411653 (1983-10-01), Razi
patent: 4413985 (1983-11-01), Wellner et al.
patent: 4535373 (1985-08-01), Yoon
patent: 4556059 (1985-12-01), Adamson, Jr.
patent: 4559041 (1985-12-01), Razi
patent: 4601710 (1986-07-01), Moll
patent: 4654030 (1987-03-01), Moll et al.
patent: 4696298 (1987-09-01), Higgins et al.
patent: 4713057 (1987-12-01), Huttner et al.
patent: 4723545 (1988-02-01), Nixon et al.
patent: 4733662 (1988-03-01), DeSatnick et al.
patent: 4733671 (1988-03-01), Mehl
patent: 4747831 (1988-05-01), Kulli
patent: 4931042 (1990-06-01), Holmes et al.
patent: 5104382 (1992-04-01), Brinkerhoff et al.
patent: 5152754 (1992-10-01), Plyley et al.
patent: 5188118 (1993-02-01), Terwilliger
patent: 938979 (1956-02-01), None
patent: 350291A3 (1990-10-01), None
patent: 0479130 (1992-04-01), None
patent: 0495633 (1992-07-01), None
patent: 0499457 (1992-08-01), None
patent: 0630619 (1994-12-01), None
patent: WO 86 00815 (1986-02-01), None

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