Tubular cutter device and methods for cutting and removing strips of tissue from the body of a patient

Methods and devices for cutting strips of tissue from masses of tissue inside or outside of the bodies of human or animal subjects. The device generally comprises a) an elongate cutting tube that has a distal end and a lumen that opens through an opening in the distal end and b) first and second cutting edges formed on generally opposite edges of the distal end of the cutting tube and separated by a distance D. The device is advanced through tissue to cut a strip of tissue of approximate width W. Width W is approximately equal to distance D.

BACKGROUND OF THE INVENTION

There are numerous medical and surgical procedures in which it is desirable to cut and remove a strip of tissue of controlled width from the body of a human or veterinary patient. For example, it may sometimes be desirable to form an incision of a controlled width (e.g., an incision that is wider than an incision made by a typical scalpel or cutting blade) in the skin, mucous membrane, tumor, organ or other tissue or a human or animal. Also, it may sometimes desirable to remove a strip or quantity of tissue from the body of a human or animal for use as a biopsy specimen, for chemical/biological analysis, for retention or archival of DNA identification purposes, etc. Also, some surgical procedures require removal of a strip of tissue of a known width from an anatomical location within the body of a patient.

One surgical procedure wherein a strip of tissue of a known width is removed from an anatomical location within the body of a patient is an ophthalmological procedure used to treat glaucoma. This ophthalmological procedure is sometimes referred to as a goniectomy. In a goniectomy procedure, a device that is operative to cut or ablate a strip of tissue of approximately 2-10 mm in length and about 50-200 μm in width is inserted into the anterior chamber of the eye and used to remove a full thickness strip of tissue from the trabecular meshwork. The trabecular meshwork is a loosely organized, porous network of tissue that overlies a collecting canal known as Schlemm's canal. A fluid, known as aqueous humor, is continually produced in the anterior chamber of the eye. In normal individuals, aqueous humor flows through the trabecular meshwork, into Shlemm's Canal and out of the eye through a series of ducts. In patients who suffer from glaucoma, the drainage of aqueous humor from the eye may be impaired by elevated flow resistance through the trabecular meshwork, thereby resulting in an Increase in intraoccular pressure. The goniectomy procedure can restore normal drainage of aqueous humor from the eye by removing a full thickness segment of the trabecular meshwork, thus allowing the aqueous humor to drain through the open area from which the strip of trabecular meshwork has been removed. The goniectomy procedure and certain prior art instruments useable to perform such procedure are described In U.S. patent application Ser. No. 10/052,473 published as No. 2002/011608A1 (Baerveldt), the entirety of which is expressly incorporated herein by reference.

At present there remains a need in the art for the development of simple, inexpensive and accurate instruments useable to perform the goniectomy procedure as well as other procedures where it is desired to remove a strip of tissue from a larger mass of tissue.

SUMMARY OF THE INVENTION

The present invention provides a device for cutting a strip of tissue of approximate width W from a mass of tissue. The device generally comprises a) an elongate cutting tube that has a distal end and a lumen that opens through an opening in the distal end and b) first and second cutting edges formed on generally opposite edges of the distal end of the cutting tube and separated by a distance D. The cutting tube is advanceable through tissue such that the first and second cutting edges will cut a strip of tissue having approximate width W, wherein the approximate width W is approximately equal to the distance D between the first and second cutting edges. In some embodiments, the strip of tissue may be aspirated or otherwise removed through the lumen of the cutter tube. In some embodiments, the device may include apparatus useable to sever (e.g., transversely cut or transect) the strip of tissue when the strip of tissue has reached a desired length.

Further in accordance with the invention there is provided a method for cutting a strip of tissue of width W from a tissue mass. This method generally comprises the steps of a) providing a device that comprises i) an elongate cutting tube that has a distal end and a lumen that opens through an opening in the distal end and ii) first and second cutting edges formed on generally opposite edges of the distal end of the cutting tube and separated by a distance D that is approximately equal to the width W of the strip of tissue to be cut; and b) advancing the distal end of the cutting tube through the mass of tissue such that the first and second cutting edges cut a strip of tissue of approximate width W. Further aspects and elements of the invention will be understood by those of skill in the art upon reading the detailed description of specific examples set forth herebelow.

DETAILED DESCRIPTION

The following detailed description, and the drawings to which it refers, are provided for the purpose of describing and illustrating certain preferred embodiments or examples of the invention only, and no attempt has been made to exhaustively describe all possible embodiments or examples of the invention. Thus, the following detailed description and the accompanying drawings shall not be construed to limit, in any way, the scope of the claims recited in this patent application and any patent(s) issuing therefrom.

One example of a needle cutter device10of the present invention is shown inFIGS. 1-4. This needle cutter device10generally comprises an elongate cutting tube14that has a distal end and a lumen27that opens through an opening in the distal end. First and second cutting edges20,22are formed on generally opposite edges of the distal end of the cutting tube14. These first and second cutting edges20,22are separated by a distance D, as shown in the distal end view ofFIG. 3B. In the particular example shown in the drawings, the first and second cutting edges20,22are located on opposite lateral sides of the distal end of the cutting tube14and a blunt, protruding tip24is located on the bottom of the distal end of the cutting tube. Also, a blunt edge26is located at the top of the distal end of the cutting tube14. Thus, only the lateral cutting edges20,22are sharp and intended to cut tissue. The blunt, protruding tip24can, in some applications, be configured and used to facilitate insertion of the device10to its intended location and/or the blunt protruding tip24may be placed In an anatomical or man made grove or channel (e.g., Schlemm's Canal of the eye) such that it will then advance through the channel or groove and guide the advancement and positioning of the remainder of the device10.

One or more bends or curves may optionally be formed in the cutting tube14to facilitate its use for its intended purpose. For example, in the embodiment of the device10shown inFIG. 2, a single bend17of approximately 90 degrees is formed near the distal end of the cutting tube14. In the embodiment of the device10bshown inFIG. 6, two separate bends of approximately 90 degrees each are formed at spaced apart locations on the cutting tube14, thereby giving the cutting tube14a generally U shaped configuration. It will be appreciated that any number of bends or curves, in any direction and of any severity may be formed in the cutting tube14to facilitate its use in specific procedures or to enable it to be inserted through tortuous anatomical channels of the body. In most cases, the degree of curvature in embodiments where a single bend or curve is formed will be between approximately 30 and approximately 90 degrees and in embodiments where more than one bend or curve are formed in the cutting tube14each such bend or curve will typically be between approximately 15 to approximately 90 degrees.

As shown inFIG. 4, when the cutting tube14is advanced through tissue, distal end first, the first and second cutting edges20,22will cut a strip ST of tissue having approximate width W, such approximate width W being approximately equal to the distance D between the first and second cutting edges20,22. The severed strip ST of tissue will enter the lumen27of the cutting tube14as the device advances. Negative pressure may be applied to lumen27to aspirate the strip ST of tissue and/or fluid and/or other matter through lumen27.

The device10may optionally include a second lumen. Such second lumen may be used for infusion of fluid through the device10or for other purposes. In the embodiment shown InFIGS. 1 and 2, the device10comprises an outer tube16in addition to the cutting tube14. The cutting tube14is of smaller diameter than the outer tube16and the cutting tube14may extend through the lumen19of the outer tube16such that a distal portion of the cutting tube14extends out of and beyond the distal end of the outer tube16, as may be seen inFIG. 2. The distal end of the outer tube16is tapered and in close approximation with the outer surface of the cutting tube14. Fluid may be infused through the lumen19of the outer tube16, through the space between the outer surface of the cutting tube14and the inner surface of the outer tube16. Fluid that is infused through the lumen19of the outer tube16may flow out of one or more apertures11formed near the distal end of the outer tube.

In some embodiments, the device10may be equipped with severing apparatus for severing (e.g., transversely cutting or transecting) the strip ST of tissue to fully excise or detach the strip ST of tissue from the remaining tissue mass and/or from the body of a human or animal subject. Such severing apparatus may comprise any suitable type of tissue cutter such as a blade, scissor, guillotine, electrode(s), laser, energy emitting tissue cutter, mechanical tissue cutter, etc.FIG. 5shows an example of an embodiment of the device10awherein monopolar or bipolar electrode(s)40are located on the distal end of the cutting tube14. When it is desired to sever the strip ST of tissue, the electrode(s) is/are energized with sufficient energy to sever the strip ST, thereby disconnecting the strip ST from the remaining tissue mass and/or the body of the human or animal subject.

In some embodiments of the device10, the cutting edges20,22may be heated such that they will cauterize as the cut. As those of skill in the art will appreciate, such heating of the cutting edges20,22may be accomplished by placement of electrode(s) near the cutting edges20,22such that, when the electrode(s) is/are energized, the cutting edges20,22will become heated to a temperature suitable for the desired cauterization function.

The needle cutter device10of the present invention may optionally be used as part of a system12, as shown inFIG. 1. The basic components of the system12comprise an aspiration pump module74and a source of irrigation fluid72, mounted on a surgical roller cart70. Control of the console functions during procedures may be accomplished by an aspiration foot pedal78which controls an aspiration pump74and variation in the height of the source of infusion fluid72to change the gravity fed pressure or flow rate of infusion fluid through the device. A pinch valve, or other means, may also be incorporated in the console to control flow of the irrigation fluid to the needle cutter device10. In embodiments that include apparatus (e.g., electrode(s)) for heating the cutting edges20,22and/or for severing the strip ST of tissue (FIG. 5), the system11may additionally comprise an electrical current source, such as an electrosurgical generator76and electrosurgical foot pedal80which controls the electrosurgical generator to deliver desired amount(s) of energy to the electrode(s) or other electrical elements (e.g., resistance heater(s), etc.) on the device10. As an option, all of the basic control functions of system12may be integrated into a single footpedal to facilitate use.

The device10may be provided as a pre-sterilized, single-use disposable probe or tip that is attachable to a standard surgical irrigation/aspiration handpiece such as that commercially available as The Rhein I/A Tip System from Rhein Medical, Inc., Tampa, Fla. After the device10has been attached to the handpiece, It may be connected to any or all of the electrosurgical generator module76, aspiration pump module74and the source of irrigation fluid72, as shown. Thus, the device10may be fully equipped for irrigation, aspiration, and electrosurgical capabilities, as described herein.

FIGS. 3A-3Dshow an example of a method for manufacturing the cutting tube14from standard tubing (e.g., stainless steel hypodermic tubing). Initially, the distal end of a tube is cut to form the lateral cutting edges20,22, the protruding tip24and the blunt top edge26. Thereafter, if it is desired to have one or more bends or curves in the cutting tube14, angular cut out(s)30may be formed in the tube14, as shown inFIG. 3C. Thereafter, the tube14is bent to bring the edges of each angular cut out30into apposition and weld, adhesive or other joining techniques are used to weld or join the apposed edges of the cut outs together, thereby forming the desired bend(s) or curve(s) in the cutting tube14. Likewise, if it is desired to have one or more bends or curves in the cutting tube14, the tube14may be directly bent to form said curves or bends without the use of angular cut outs(s)30. It may be appreciated that the use of angular cut-out(s)30allow a tube10of a given diameter to incorporate a curve or angle in a more compact form than is possible by bending tubing10of a given diameter to said curve or angle without kinking or damaging tube10.

The device10and system12are useable to perform a variety of procedures wherein it is desired to form an incision or opening of a desired width or to remove, from a mass of tissue, a strip ST of tissue of a desired width.

One particular procedure that may be performed to treat glaucoma, using the device10and system12of the present invention, is a goniectomy. As explained herein a goniectomy procedure is an ab interno surgical procedure wherein a sector of the trabecular meshwork is removed from the eye of the patient to facilitate drainage of aqueous humor from the anterior chamber of the eye through Schlemm's Canal and the associated collector channels, thereby relieving elevated intraocular pressure.

To perform a goniectomy procedure using the device10, first a small incision is made in the cornea at about 3 o'clock in the left eye, or at about 9 o'clock in the right eye. A 1.5 mm slit knife may be used to make this incision.

The device10is attached to the source of irrigation fluid72(e.g., basic balanced salt solution) such that irrigation fluid will flow through lumen19of the outer tube16and out of outflow aperture11. The device10is then inserted through the incision and into the anterior chamber of the eye (with irrigation flowing). In some cases, during the insertion of the device10, the source of irrigation fluid72may initially connected to the device such that the irrigation fluid will flow through the lumen27of the cutter tube14. In this manner, irrigation fluid will begin to infuse into the anterior chamber of the eye as soon as the distal end of the cutter tube14has entered the anterior chamber, rather than being delayed until the larger outer tube16and aperture11have been advanced through the incision and into the anterior chamber. By this alternative approach. Irrigation fluid may be caused to flow out of the distal end of the cutter tube14as the device10is being inserted, thereby spreading or opening the incision by hydraulic force while in addition Increasing the fluid pressure in the anterior chamber. Such spreading or opening of the incision may facilitate advancement of the larger diameter outer tube16through the incision. Pressurizing the fluid in the anterior chamber causes the anterior chamber to deepen and may facilitate maneuvering of device10within the anterior chamber. In cases where this alternative approach is used, the source of infusion fluid72may be disconnected from lumen27of the cutter tube14after the device10has been inserted into the anterior chamber and, thereafter, the infusion fluid source72may be reconnected to lumen19of outer tube16such that infusion fluid will flow out of aperture11. Negative pressure (e.g., via aspiration pump module74) may then be applied to lumen27of the cutter tube14so as to aspirate fluid and debris through lumen27as shown inFIG. 4. The vertical height of the infusion fluid source72may be adjusted to provide sufficient gravity feed of infusion fluid to make up for the volume of fluid or matter being aspirated from the anterior chamber through lumen27, thereby maintaining the desired pressure of fluid within the anterior chamber during the procedure.

A lens device (e.g., Ocular Swan-Jacob Autoclavable Gonloprism, Model OSJAG, Ocular Instruments Inc., Bellevue, Wash.) may be positioned on the anterior aspect of the eye to enable the physician to clearly visualize the angle of the eye where the segment of trabecular meshwork is to be removed. Under direct visualization, the device10is advanced until the distal tip of the cutter tube14is positioned adjacent to the trabecular meshwork at the location where the strip ST is to be removed. Thereafter, the protruding tip24is advanced through the trabecular meshwork and into Schlemm's Canal.

The device10is then advanced along Schlemm's Canal, thereby causing the cutting edges20,22to cut a strip of the trabecular meshwork, thereby creating an opening through which aqueous humor may drain from the anterior chamber of the eye.

After a strip of tissue of the desired length (e.g., about 2-10 mm) has been cut by the lateral cutting edges20,22, any optional tissue severing apparatus (e.g., electrode(s)40may be used (if present) to transect or sever the strip ST of tissue thereby disconnecting it from the patient's body and allowing it to be aspirated or drawn into or through lumen27.

Thereafter, the aspiration is stopped, the device10is removed from the eye, and the infusion is stopped.

Following completion of the surgery, aqueous humor will drain from the anterior chamber through the opening that was created by removal of the strip of tissue from the trabecular meshwork TM.

Although the invention has been described above with respect to certain embodiments and examples, it is to be appreciated that such embodiments and examples are non-limiting and are not purported to define all embodiments and examples of the invention. Indeed, those of skill in the art will recognize that various modifications may be made to the above-described embodiments and examples without departing from the intended spirit and scope of the invention and it is intended that all such modifications be included within the scope of the following claims.