Biopsy device with automatic aspiration

The invention provides a disposable endometrial biopsy device comprising an elongated blunt-end catheter with distally placed tissue acquisition side-hole and proximally attached aspiration syringe with spring-loaded plunger having latching mechanism to release plunger for induction of aspiration. The device has a pin-hole channel or filter acting as a tissue trap between the catheter channel and the syringe in order to prevent aspiration of tissue into the body of the syringe.

TECHNICAL FIELD

This invention relates generally to surgical instruments. More particularly, the invention relates to a biopsy device that automatically creates suction to aspirate a specimen into the device.

BACKGROUND OF THE INVENTION

Routine endometrial biopsy is commonly performed using a flexible 3-mm catheter with rounded distal end having a side-hole for curettage and collection of tissue. Such catheters typically contain a flexible internal plunger that seals with the internal surface of the catheter. When the internal plunger is pulled back, suction is created. The suction is used to obtain endometrial tissue as the catheter is passed back and forth with rotation within the uterine cavity while the distal side hole scrapes tissue from the internal walls of the cavity. See, e.g., Zinnanti U.S. Pat. No. 5,069,224, Fowler U.S. Pat. No. 5,807,282, and Cornier U.S. Pat. No. 6,042,552.

The use of a flexible catheter follows the natural contours of the uterine cavity, which is an advantage to patient care, causing less pain and tissue trauma compared to needle or ridged-cannula biopsy devices. However, the process of transferring the sample from the catheter to a specimen container is inherently difficult with such typical biopsy devices because the flexible plunger must be reintroduced into the flexible catheter to expel the contents. This process is slow and technically difficult, and may result in loss of the sample, leading to the need for a second procedure.

Additionally, the limited volume of such typical endometrial catheters frequently does not create enough suction to obtain an adequate sample, and multiple passes with the same catheter, consisting of multiple iterations of obtaining and expelling a sample, must be performed. This process is further complicated by the need to prevent the sterile catheter tip from touching a non-sterile specimen container in order to prevent contamination when multiple passes are required.

Thus, although such prior-art devices can be simple to use and manufacture, each suffers from the disadvantages of a limited amount of suction and the need to force a long, flexible plunger back into the device in order to retrieve the specimen. These disadvantages result in loss of time and increased patient discomfort because the catheter must be reintroduced multiple times to retrieve an adequate sample and because the difficulty of replacing the plunger to retrieve the sample frequently leads to loss of sample, thus requiring a second procedure.

A few endometrial tissue collection systems employ the use of a syringe. The syringe has the advantage of creating more suction for aspiration so that an adequate sample is obtained each time; however, in currently available products, the plunger must be manually withdrawn from the syringe barrel to create suction. This action of pulling on the syringe plunger at the same time the catheter is inserted into the uterine cavity is inherently dangerous and may cause inadvertent harm or uterine perforation as the catheter is being pushed forward toward the patient and as the syringe is being pulled backward.

Spring-biased aspiration biopsy devices have been previously described by Lee U.S. Pat. No. 4,664,128, Hut U.S. Pat. No. 5,159,933 and DeSantis et al. U.S. Pat. No. 5,971,939 A. These devices have a variety of disadvantages based on the complicated grips, guides, and holders that encase the syringe and therefore introduce difficulty in retrieving the specimen if it is suctioned into the syringe. Indeed, the guides and holders described in Hut U.S. Pat. No. 5,159,933 and DeSantis et al. U.S. Pat. No. 5,971,939 A are in place to prevent overpressure from suctioning the tissue sample into the syringe.

Therefore, it would be desirable to provide an aspiration biopsy device that overcomes the aforementioned and other disadvantages.

SUMMARY OF THE INVENTION

One aspect of the present invention is an aspiration biopsy device. In one embodiment, the device is an endometrial biopsy catheter with proximally attached aspiration syringe having a pin-hole channel or filter acting as a tissue trap to prevent aspiration of tissue from the catheter into the syringe. In another embodiment, the biopsy device is an aspiration biopsy device with proximally attached syringe having spring-loaded plunger and latching mechanism to automatically create aspiration suction when the latch is released.

Another aspect of the present invention is a method of performing a biopsy procedure. In the method, an aspiration biopsy device is provided, the device comprising a catheter having a distally placed tissue acquisition side hole and a proximally attached syringe having a spring-loaded plunger and a latching mechanism. A distal portion of the device is inserted into a body cavity. Once the device portion is in place within the body cavity, the latching mechanism is manipulated to release the spring-loaded plunger, thereby automatically producing aspiration suction within the syringe. The device portion is moved in and out with a twirling motion, thereby collecting a biopsy sample via the distally placed tissue acquisition side hole. Once the biopsy sample is obtained, the device is removed and the sample is easily expelled by depressing the spring-loaded plunger with a thumb

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

One aspect of the present invention is a biopsy device. In one embodiment, the device is an endometrial biopsy catheter with a proximally attached aspiration syringe, the catheter having a pin-hole channel or filter acting as a tissue trap to prevent aspiration of tissue from the catheter into the syringe. In another embodiment, the device is an aspiration biopsy device with a proximally attached syringe that has a spring-loaded plunger and a latching mechanism to automatically create aspiration suction when the latch is released. Devices in accordance with the present invention are illustrated inFIGS. 1-7.

FIG. 1shows a biopsy device, in accordance with the present invention, ready for use. The device includes a catheter110(also referred to herein as an endometrial biopsy catheter) and a proximally attached syringe120(also referred to herein as an aspiration syringe). The term “catheter” is defined herein as an elongated, at least semi-flexible tube such as is illustrated in the figures. The term “syringe” is defined herein as a structure that comprises a hollow barrel fitted with a plunger, such as is illustrated in the figures. The term “proximal” (and its variants) refers to the portion of a device, or the portion of an element of the device, that is adjacent to the operator when the device is in use. The term “distal” (and its variants) refers to the portion of the device, or the portion of an element of the device, that is adjacent to the patient when the device is in use. InFIGS. 1 and 2, the distal end of the device is at the left and the proximal end of the device is at the right.

As illustrated inFIG. 1, catheter110has a rounded distal end (i.e., the catheter has a blunt distal end) and includes a distally placed side hole111used for acquisition of a tissue sample into the interior or lumen of the catheter. Catheter110also includes a tissue trap112disposed in a proximal portion of the catheter that serves to prevent aspiration of biopsied tissue from the catheter into the aspiration syringe seen at120. Tissue trap112may include either a filter113, as illustrated inFIG. 1, or a pin-hole channel114, as illustrated inFIG. 3.

Syringe120is proximally attached to catheter110. I.e., syringe120is attached to a proximal portion of catheter110. Syringe120may be attached to catheter110by any appropriate means, including, for example, the two elements being manufactured together to form an integral whole, the two elements being adhesively or otherwise bonded one to the other, or the two elements being snap-fit or otherwise mechanically connected one to the other.

Syringe120comprises a plunger121and a barrel122. As seen inFIG. 1, plunger121is spring loaded, a spring123being held compressed between flange124of barrel122and the proximal end125of plunger121by a latching mechanism126. The plunger proximal end serves as both a thumb (or finger) control portion of plunger121(i.e., the portion of the plunger to which typically a thumb is applied to depress the plunger, as seen inFIG. 7) and as a seat for latching mechanism126when the mechanism is latched to hold spring123in a compressed state as seen inFIG. 1.

When latching mechanism126is released from proximal end125of plunger121, a distal portion of plunger121is automatically drawn through and partially out of barrel122by the expansion of spring123, as seen inFIG. 2. Because plunger121includes a tip127that substantially seals with the interior wall of barrel122, the withdrawing of plunger121in response to release of latching mechanism126automatically creates suction within barrel122that is communicated to catheter110via tissue trap112. This suction is used to aspirate a tissue sample into the biopsy device through side hole111. The aspirated tissue sample is prevented from entering syringe120and is maintained within the lumen of catheter110because, as is evident from, e.g.,FIG. 1, barrel122is in communication with catheter110via tissue trap112.

Operation of the device is illustrated, for example, inFIG. 2, which shows at least a portion of catheter110inserted into a uterine cavity130. A tissue sample140has been aspirated into the lumen of catheter110through tissue acquisition side hole111(indicated by the curved arrow adjacent to the hole) as a result of releasing plunger121while catheter110is in place within the body cavity. Tissue acquisition is facilitated by moving catheter110in and out with a twirling motion during aspiration.

FIG. 6also shows a tissue sample140within the lumen of catheter110. Syringe120may be sized to provide sufficient aspiration power to completely fill the lumen of catheter110with sample, thus avoiding the need for multiple passes with the device. Note that as seen inFIG. 6tissue trap112has prevented aspiration of tissue from catheter110into syringe120, the barrel122of syringe120being connected to catheter110via tissue trap112.

After latching mechanism126has been released from proximal end125of plunger121, allowing spring123to expand, plunger121then becomes a depressible plunger. I.e., the plunger may now be depressed by application of, for example, an operator's thumb to the proximal end125of plunger121. Depressing plunger121expels aspirated tissue from the lumen of catheter110as illustrated inFIG. 7, which shows the device being held stably over a specimen container150with the operator's thumb depressing spring-loaded plunger121to expel collected sample140from side hole111in a controlled fashion. Thus, there is no need to disassemble the syringe from the catheter to obtain the aspirated tissue, nor is any reconfiguration of the device required, the device being automatically configured for sample delivery into a specimen container.

FIG. 4illustrates one embodiment of latching mechanism126in which the latching mechanism is a single piece that is movably attached to one or more edges of flange124of barrel122. Flange124is illustrated in the figures as a substantially circular or oval ring at the proximal end of barrel122but could, alternatively, be one or more tabs extending outward from the body of barrel122or even a substantially straight proximal portion of barrel122.FIG. 5illustrates another embodiment of latching mechanism126in which the latching mechanism is fully detachable from syringe120and comprises two segments, the first segment126abeing sized and structured to be removably placed over plunger proximal end125to maintain spring123in a compressed state, and the second segment126bbeing a cap-like structure that may be fitted over flange124or the flange of a standard syringe. In both embodiments, the latching mechanism is movably attached to syringe120to permit not only easy release of the latching mechanism from the proximal end125of plunger121, but also reattachment of the latching mechanism to plunger end125when plunger121is depressed. Thus, latching mechanism126facilitates plunger121being returned to a spring-loaded state after expulsion of an aspirated sample from the biopsy device (i.e., providing a mechanism for re-latching the spring-loaded plunger), preparing the device for repeated use if desired. Note that the location and design of the latching mechanism allows the biopsy device to be operated with one hand. In each of the embodiments illustrated inFIGS. 1-7, the latching mechanisms126,126aare coupled to substantially diametrically opposing locations on barrel122.

Yet another aspect of the present invention is a method of performing a biopsy procedure. In the method, an aspiration biopsy device is provided, the device comprising a catheter having a distally placed tissue acquisition side hole and a proximally attached syringe having a spring-loaded plunger and a latching mechanism. The device may be a device such as has been described above and illustrated inFIGS. 1-7.

A distal portion of the device is inserted into a body cavity. For example, all or a portion of catheter110may be inserted into a uterine cavity130as seen inFIG. 2. Once the device portion is in place within the body cavity, the latching mechanism is manipulated to release the spring-loaded plunger, thereby automatically producing aspiration suction within the syringe that is communicated to the catheter. The device portion is moved in and out with a twirling motion, thereby collecting a biopsy sample via the distally placed tissue acquisition side hole (e.g., side hole111). Passage of the biopsy sample from the catheter into the syringe may be prevented by the inclusion within a proximal portion of the catheter of a tissue trap comprising a filter or a pin-hole channel.

After collecting the biopsy sample, the device portion is removed from the body cavity. The device may then be held over a specimen container, and the spring-loaded plunger may be depressed, e.g., using a thumb, to expel the sample into the specimen container as, for example, illustrated inFIG. 7. After the sample has been expelled into the specimen container, the latching mechanism may be manipulated to restrain the spring-loaded plunger (i.e., to return the spring-loaded plunger to its starting position and status), thereby preparing the device for repeated use if desired.