Surgery – Instruments – Electrical application
Reexamination Certificate
1999-12-23
2001-10-30
Dvorak, Linda C. M. (Department: 3739)
Surgery
Instruments
Electrical application
C600S564000
Reexamination Certificate
active
06309388
ABSTRACT:
FIELD OF THE INVENTION
The present invention discloses a device for electrocautery of tissue, in particular, for an improved electrocautery for performing a symmetric conization, and more particular, a device for performing electrocautery conization of a uterine cervix.
BACKGROUND OF THE PRESENT INVENTION
In medicine, biopsying a sample of tissue remains the gold standard for pursuing a diagnosis of tissue pathology. The biopsied tissue is then examined histologically for evidence of dysplasia and cancerous transformation to yield the diagnosis.
The treatment of choice, particularly in the women of childbearing age, for cervical dysplasia involving the cervical canal or for more than one degree of discrepancy between the degree of dysplasia represented on the Pap smear versus colposcopic directed biopsy is conization of the cervix. In a conization of the cervical tissue, the traditional cold knife procedure involved removing a cone shaped tissue specimen from the cervix with the axis of the cone centered on the axis of the endocervical canal. The cone base is positioned at the external cervical os, oriented with the cone apex toward the internal cervical os. With the advent of electrocautery devices the specimen shape may be refined to a more anatomically directed biopsy specimen that maintains a more accurate depth of surgical resection but seldom resembles an actual cone. There are a number of methods and devices for performing this procedure.
The ideal endocervical biopsy yields a cylinder of tissue approximately two centimeters in length and five to seven mm deep on all faces centered on the axis of the endocervical canal. Seldom is the ideal achieved, but there are several methods available. First, surgically excise the tissue. Surgical excision, i.e., cold knife conization, is accomplished with a conventional scalpel.
Second, use a loop electrosurgical excision procedure (LEEP) to first create a superficial excision followed by a second deeper excision extending further along the endocervical canal toward the internal cervical os. The loop excision uses a loop of wire for electrocautery excision of the specimen. The loop is handheld with the first pass depth less than two centimeters, consequently, the need for more than one pass in order to approach the ideal endocervical treatment depth.
Third, use a modified LEEP electrode that is shaped to combine the superficial and deep excisions into one pass. The modified LEEP conization electrodes consist of an insulated stiff rod with a wire electrode extending from the tip of the rod to a cross arm, which approximates the configuration of a cone specimen.
A fourth method uses CO
2
laser energy in lieu of a scalpel for performing an excisional cervical conization.
Sharp excision techniques using devices such as a scalpel, have the advantage for controlled tissue removal and minimal tissue injury with preservation of resection margins for clarity of histologic analysis, but the procedure has poor anatomic control. A drawback to cold knife conization excision over LEEP is the increased blood loss from the wound edge. Because of their size, including the handle, scalpels are more difficult to wield in the closer confines of the vaginal vault. A number of devices for mounting, holding, and modifying scalpel blades have been developed, but these devices have proven to be either difficult to keep the excision centered or difficult to turn while in the vaginal vault.
LEEP has improved blood loss control, but the straight stiff rods are difficult to use within the confines of the vaginal vault because of the angle differences between the long axis of the vaginal vault to the long axis of the endocervical canal. The difficulty in obtaining proper alignment of the device to the axis of the endocervical canal leads to off centered and or tilted excisions that run a significant risk of only partially excising abnormal tissue, completely missing the abnormal tissue, and or removing excessive amounts of normal tissue.
What is needed is a device that is capable of concentrically removing cervical tissue around the endocervical axis of rotation at an appropriate biopsy depth with minimal blood loss and minimal injury to cervical margin tissues.
SUMMARY OF THE INVENTION
The present invention is an improved device for symmetric electrocautery removal of tissue of a human patient. The device comprises a hollow housing, an electrocautery head and a mechanism for rotating the electrocautery head while conducting electricity to the electrocautery head.
The housing is elongate along a first longitudinal axis and has a proximal portion, the proximal portion having a proximal end and a distal end. The hollow housing may also have a distal portion, which has a second longitudinal axis, and is distal to the distal end of the proximal portion. This second longitudinal axis is at a selectable angle to the first longitudinal axis.
The rotating mechanism is operably engageable within the hollow housing along the first and second longitudinal axes and is adapted to conduct electrocautery energy from an electrode proximate to the housing proximal portion proximal end to a coupling proximate the distal end of the first portion or proximate the distal portion, if the distal portion is used. The rotating mechanism ends in a coupling that is aligned along the second longitudinal axis. The rotating mechanism rotates the coupling with a removable handle proximate the proximal end of the housing.
The present invention anticipates several different types of rotating mechanisms. In one embodiment, the rotating mechanism uses a flexible cable, preferably metal, or at least electrically conducting. The flexible cable may be single strand or multi-strand as either a braid or a coil.
The electrocautery head carries an electrocautery wire and is operably and electrically engageable with the coupling and rotatable around the second longitudinal axis. When electrocautery energy is delivered to the electrocautery head, the rotating mechanism rotates the electrocautery head about the second longitudinal axis, symmetrically electrocauterizing tissue of a human patient about that second longitudinal axis. The present invention anticipates that the electrocautery head is removable and replaceable with different styles, shapes and configurations for the body and the wire.
The present invention anticipates several conformations for the housing. Where only a proximal portion for the housing, is used, the present invention may use either a flexible cable or a U-joint for completing the bend and aligning the electrocautery head with the endocervical canal. With this arrangement, it is preferable to use an electrocautery head that has an extended tip for maintaining alignment and orientation of the electrocautery head with the endocervical canal.
Where a proximal portion and a distal portion are used for the housing, preferably a flexible hinge joins these two portions. The hinge may be friction fit to provide for some movement when sufficiently forced, but readily maintaining a selected angle when not forced to move. Alternatively, the present invention contemplates a locking mechanism using a bracket pivotably mounted to the distal portion and having a more proximal end that may operable engage the housing proximal portion. Preferably, the bracket includes two halves shaped to provide for shielding from possible electrical energy exposure at the hinge area and provide for selectable angular movement of the proximal portion with respect to the distal portion. The engagement of the bracket with the proximal portion may be with nibs engaging detents, a ratchet and pawl, interdigitating teeth, or similar engaging mechanisms.
The bracket is preferably spring biased relative to the distal portion for holding the bracket in the locking position with the proximal portion. Squeezing the bracket halves against the spring bias pivots the bracket in relation to the distal portion and releases the bracket from the proximal portion. While released the angle of the proximal portion in relation to
Cotterell Gregory F.
Dvorak Linda C. M.
Mayo Foundation for Medical Education and Research
Ruddy David M.
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