Patent Application
20080228164
The present disclosure relates generally to site markers for breast biopsy procedures.
In the diagnosis and treatment of breast cancer, it is often necessary to perform a biopsy to remove tissue samples from a suspicious mass. The suspicious mass is typically discovered during a preliminary examination involving visual examination, palpation, X-ray, magnetic resonance imaging (MRI), ultrasound imaging or other detection means.
When a suspicious mass is detected, a sample is taken by biopsy, and then tested to determine whether the mass is malignant or benign. This biopsy procedure can be performed by an open surgical technique, or through the use of a specialized biopsy instrument. To minimize surgical intrusion, a small specialized instrument such as a biopsy needle is inserted in the breast while the position of the needle is monitored using fluoroscopy, ultrasonic imaging, X-rays, MRI or other suitable imaging techniques.
In stereotactic needle biopsy, the patient lies on a special biopsy table with her breast compressed between the plates of a mammography apparatus and two separate X-rays are taken from two different points of reference. A computer then calculates the exact position of the mass or lesion within the breast. The coordinates of the lesion are then programmed into a mechanical stereotactic apparatus which advances the biopsy needle into the lesion with precision. At least five biopsy samples are usually taken from locations around the lesion and one from the center of the lesion.
Regardless of the method or instrument used to perform the biopsy, subsequent examination of the surgical site may be necessary, either in a follow up examination or for treatment of a cancerous lesion. Treatment often includes a mastectomy, lumpectomy, radiation therapy, or chemotherapy procedure that requires the surgeon or radiologist to direct surgical or radiation treatment to the precise location of the lesion. Because this treatment might extend over days or weeks after the biopsy procedure, and the original features of the tissue may have been removed or altered by the biopsy, it is desirable to insert a site marker into the surgical cavity to serve as a landmark for future identification of the location of the lesion.
However, some biopsy site markers may not be visible under all available modalities. When cancer is found at a biopsy site that has been previously marked with a site marker, the poor visibility of the biopsy site marker under ultrasound or other visualization modalities, may require that the patient undergo an additional procedure that places an additional device at the biopsy site to enable the surgeon to find the biopsy site in subsequent procedures. One known technique has been to place a breast lesion localization wire at the biopsy site. The localization wire is typically placed at the biopsy site via mammography and/or ultrasound.
Commonly assigned US Patent Publication 2006/0173296 discloses markers that use expandable filament portions to ‘hold’ a site marker in place within a biopsy cavity. That is, a site marker may include a bio-absorbable filament portion, such as a suture, with a marker attached thereto, where the marker is visible under multiple modalities and the suture will inhibit migration of the marker within the biopsy cavity. The filament portions of these structures typically define a site marker diameter that is greater than the outer diameter of the cannula. To insert a site marker within a biopsy site, the site marker is compressed (at least partially elastically deformed) to a dimension that will permit the site marker to be interposed within the cannula, the site marker is interposed within an opening of the cannula, the site marker and cannula are sterilized, the cannula is inserted within the biopsy canal such that the opening is within the biopsy site, and the marker is deployed into the biopsy site. Once deployed, the site marker will expand as the filament portions exit the cannula in reaction to the elastic deformation. The site marker will expand until the elastic deformation is eliminated or portions of the site marker interfere with the inside portions of the biopsy cavity.
The site marker and cannula must be sterile in order to be placed into a biopsy cavity. However, the elastically deformed filament portions, or other materials, plastically deform within the cannula due to the heat of sterilization (essentially converting some of the elastic deformation to plastic deformation) and may expand less upon exiting the cannula than a site marker that has no plastic deformation due to the heat of sterilization. Such a site marker may undesirably migrate within the biopsy cavity.
Accordingly, there is a need for site markers made from biocompatible materials that are visible under various modes of imaging to reduce the number of procedures that patients must undergo in detection and treatment of cancer, while being compatible with sterilization and packaging techniques.
An embodiment includes a site marker deployment system that includes a deployment device having an inner cannula and a site marker that may be selectively interposed within the inner cannula. The site marker includes at least one generally elongated filament member. The filament member is selectively configurable between a first configuration, where the site marker can not be interposed within the inner cannula, and a second configuration, where the site marker may be interposed within the inner cannula. A portion of the site marker is elastically deformed when the site marker is interposed within the inner cannula. The site marker deployment system also includes a restraining member selectively interposed within the inner cannula and selectively engaging the site marker such that a force exerted on the restraining member may urge the site marker at least partially into the inner cannula.
Referring now to the drawings, illustrative embodiments are shown in detail. Although the drawings represent some embodiments, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present invention. Further, the embodiments set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description.
Referring now to the drawings, preferred illustrative embodiments are shown in detail. Although the drawings represent some embodiments, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present invention. Further, the embodiments set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description.
Referring to
The outer cannula 38 has an axis B-B and extends from an open proximal end 60 to an open distal end 62, which is separated from proximal end 60 by a distance B. The outer cannula 38 may be made from a medical grade resin or other MRI compatible material. A depth limiting member 64, such as a rubber o-ring, may be moveably disposed on outer cannula 38 to limit the insertion depth of outer cannula 38 into the patient's body. The outer cannula 38 also includes an inner lumen 66 therethrough, which is open to communication with a fluid conduit 68 for supplying fluids, such as saline and anesthetics, or removing fluids, such as blood, from the patient's body. In the embodiments illustrated, the distance A is slightly greater than the distance B.
In the embodiment of
As best seen in
At least one of the filament members 80, 82, 84, 86 are selectively configurable between a first deployed configuration (
The inventors have discovered that some site markers, when sterilized by heat in the retracted configuration (with the site marker completely interposed within an inner cannula, such as the inner cannula 42) may impose a permanent ‘set’ in the site marker. That is, the site marker, while elastically deformed within an inner cannula, may plastically deform due to the application of heat. When a plastically deformed site marker is deployed, the site marker will not fully expand to the deployed configuration, and may migrate from the desired deployment location.
The site marker 24 may be packaged in a sterile enclosure (not shown) in the configuration generally illustrated in
In this sterilization configuration of
Alternatively, the site marker 24 would be pulled into the inner cannula 42 as the trigger wire 70 is pulled adjacent the proximal wire end (toward the direction of arrow R). The trigger wire 70 is further pulled generally in the direction of the arrow R toward the configuration of
As illustrated, the site marker 24 is deformed when the site marker 24 is interposed within the inner cannula. At least a portion of the site marker 24 is elastically deformed, although the site marker may be partially plastically deformed. That is, not all portions of the filament members 80, 82, 84, 86 may rebound to the sterilization configuration after being released from the inner cannula 42. Additionally, the deployed configuration may be restricted as the site marker 24 contacts portions of the biopsy cavity 30, thereby preventing a full expansion of the site marker 24.
As discussed above, a sterilization configuration is illustrated in
The device 140, further includes a restraining member, or retracting member, 160 having a pair of finger members 162 (as best seen in
The device 140 also includes a biasing member 174 interposed between the inner cannula inner lip 148 and the retracting member flange 166. Thus positioned, the biasing member 174 will urge the retracting member 160 in the direction R relative to the inner cannula 142. In the configuration illustrated in
The inner cannula inner lip 148 circumscribes the outer retracting surface 172, while the inner retracting surface 170 circumscribes the push rod outer surface 158. The push rod outer surface 158 is defined by a push rod distal edge 176 (as best seen in
As discussed in greater detail below, the biasing member 174 is adapted to urge the retracting member 160 such that the site marker 124 is urged into the inner cannula 142. The biasing member 174 provides a predetermined force to urge the site marker 124 within the inner cannula 142, thereby preventing a user from providing an undesirable amount of force on the site marker 124.
As best seen in
Each of the filament members 180, 182, 184, 186, 194 extend between the first end connection 188 and the second end connection 190. In the embodiment illustrated, the filament member 180 is shorter than the filament members 182, 184, 186, 194. Thus configured, the filament member 180 will remain generally straight while the filament members 182, 184, 186, 194 are resiliently curved.
At least one of the filament members 180, 182, 184, 186, 194 is selectively configurable between a first deployed configuration (
As best illustrated in
As illustrated in
In an embodiment of operation, the device 140 may be used as follows. A user removes the device 140 from a sterile package (not shown). The user then detaches the retracting member 160 from the inner cannula 142 by uncoupling the flange retainer 202 from the device 140 to permit the biasing member 174 to expand. As the biasing member 174 expands, the retracting member 160 moves in the direction of arrow R relative to the inner cannula 142 while the pushrod 150 remains generally in a constant axial position relative to the inner cannula 142. As the retracting member 160 moves, the pushrod retainer 200 prevents the pushrod 150 from moving in the direction of the arrow R. As the retracting member 160 moves in the direction of arrow R relative to the inner cannula 142 from the configuration of
The user then detaches the pushrod retainer 200 from the device 140 and inserts the inner cannula 142 into an introducer, such as the outer cannula 38, to position the device 140 relative to the biopsy cavity 30. The user may then urge the push rod 150 in the direction D to move the site marker 124 out of the inner cannula 124 and into the biopsy cavity 30, or other desired location, as best illustrated in
As discussed in greater detail below, the inner cannula 242 may be interposed within an outer cannula (not shown) that extends from an open proximal end to an open distal end. The outer cannula may be made from a medical grade resin or other MRI compatible material. A depth limiting member, such as a rubber o-ring, may be moveably disposed on outer cannula to limit the insertion depth of outer cannula into the patient's body.
In the embodiment illustrated, the deployment device 240 includes a restraining member, or trigger wire, 270 interposed therein. The trigger wire 270 extends from a distal wire end 272 to a proximal wire end 274. The deployment device 240 also includes a push rod 276 and a biasing member 278. As discussed in greater detail below, the trigger wire 270 is configured to pull a site marker, such as the site marker 224, into the inner cannula 242 after sterilization and prior to insertion of the inner cannula 342 into the tissue 20.
As best seen in
At least one of the filament members 280, 282, 284, 286 is selectively configurable between a first deployed configuration (
The push rod 276 is at least partially interposed within the inner cannula 242. The push rod 276 includes a push rod distal end 312, a push rod handle 314 at a push rod proximal end 316, and a generally cylindrical push rod outer surface 318.
The biasing member 278 is interposed between the proximal inner cannula end 246 and the push rod handle 314. Thus positioned, the biasing member 278 will urge the push rod 276 in the direction R relative to the inner cannula 242. In the configuration illustrated in
The site marker 224 may be packaged in a sterile enclosure in the configuration generally illustrated in
In this sterilization configuration of
As illustrated, the site marker 224 is deformed when the site marker 224 is interposed within the inner cannula 242. At least a portion of the site marker 224 is elastically deformed, although the site marker 224 may be partially plastically deformed. That is, the filament members 280, 282, 284, 286 may not rebound to the sterilization configuration of
As illustrated in
In the embodiment illustrated,
An embodiment of deploying a site marker using the device 240 is as follows. The device 240 is assembled as generally seen in
After sterilization, the device 240 may be then stored for later use, as the site marker 224 is generally retained in the sterilization configuration of
After removal of the device 240 from the packaging 298, the trigger wire 270 and the push rod 276 are urged by the biasing member 278 generally in the direction of arrow R as the site marker 224 is retracted within the inner cannula toward the position of
To deploy the site marker 224, the trigger wire 270 is pulled in the general direction of the arrow R as the push rod is held in a generally unmoved position relative to the inner cannula 242. Once the trigger wire 270 is pulled out of contact with the site marker 224, the trigger wire 270 may be removed from the inner cannula 242 and the inner cannula 242 may be interposed within an outer cannula such as the outer cannula 38 to position the distal inner cannula end 244 adjacent a desired location for marker deployment. The push rod 276 may then be moved generally in the direction of the arrow D until the site marker 224 is no longer interposed within the inner cannula 242, thereby deploying the site marker 224 into the desired location, such as the biopsy cavity 30. After deployment, the device 240 may be removed from the patient.
The deployment device 340 also includes a trigger wire 370 and a push rod 376 interposed within the inner cannula 342. The site marker 324 also includes filament members 380, 382, 384, 386 connected to the marker end 328. The central filament member 390 extends from the marker end 328 and may be looped to retain the permanent marker 330.
Similar to the discussion above, the deployment device 340 is sterilized in generally the configuration of
After sterilization, the trigger wire 370 and the push rod 376 are urged generally in the direction of arrow R as the site marker 324 is retracted within the inner cannula toward the position of
To deploy the site marker 324, the trigger wire 370 is pulled in the general direction of the arrow R as the push rod is held in a generally unmoved position relative to the inner cannula 342. Once the trigger wire 370 is pulled out of contact with the site marker 324, the push rod 376 may be moved generally in the direction of the arrow D until the site marker is no longer interposed within the inner cannula 342, thereby deploying the site marker 324.
As desired, the devices 140, 240 may be positioned within the packaging 298 the pushrod retainer 200, or any suitable device that will axially restrain portions of a device relative to other portions.
In general, the site markers described herein are made, at least in part, from biocompatible materials such as, but not limited to, titanium, stainless steel, and platinum. These materials have appropriate densities for radiographic imaging, appropriate surface characteristics for ultrasonic imaging, and appropriate magnetic characteristics for magnetic resonance imaging. The site markers are preferably made from titanium; however, it is understood that any suitable biocompatible material may be used. Alternatively, the site markers may be made of a bio-absorbable material with a permanent marker attached thereto. In the embodiments illustrated, the filament members have an aspect ratio of at least about 10:1, although other suitable aspect ratios may be used.
After installation in a biopsy cavity, over a predetermined time period such as three weeks to six months, the bio-absorbable materials described herein may be absorbed by the body, such that only permanent marker 196 (if provided), remains within the body at the biopsy cavity 30. Because permanent markers are captured within the tissue 20 prior to absorption thereof by the body, permanent markers are restricted from migrating from within the tissue 20, such as within the biopsy cavity 30. Indeed, movement of a permanent marker is limited to the internal cavity immediately adjacent where a site marker is deployed. This insures that permanent markers remain within an area, such as the biopsy cavity 30 location, after the biopsy cavity 30 has closed to permit follow-up imaging of the biopsy site.
In other embodiments, a site marker may be constructed, at least in part, of a temperature dependent material. These site markers would not fully expand from the retracted configuration into the deployed configuration until heat is applied to the site marker. Deploying the site marker into a biopsy cavity provides a sufficient level of heat generated from the body to encourage the site marker to automatically expand into the second post-deployment configuration after deployment. Such materials include the shape-memory metal nitonol.
Once released from the deployment device and into the biopsy cavity, the site marker automatically springs (due to the elastic deformation) into the deployed configuration having a size and shape defined by the biopsy cavity such that the site marker is easily visible under various imaging modalities.
After installation in a biopsy cavity, such as biopsy cavity 30, over a predetermined time period such as three weeks to six months, the bio-absorbable filament members are absorbed by the body, such that only a permanent marker remains within the body within the biopsy cavity location, and is visible under one or more modalities such as X-ray, magnetic resonance imaging (MRI), or ultrasound imaging. Filament member may be absorbed by tissue ingrowth, leaving only a permanent marker, which may be retained in place by the tissue ingrowth.
In the embodiments illustrated, the permanent markers may be constructed of a material that is not absorbed by the body. Alternatively, the permanent markers may be a semi-permanent marker that bio-absorbs slower than the filament member. Because the movement of the permanent markers is restricted by the filament members prior to absorption thereof by the body, the permanent markers are restricted from migrating from within biopsy cavity. This insures that the permanent markers remain within the biopsy cavity to permit follow-up imaging of the biopsy site. The permanent marker may also be contained within the filament members to ‘free float’ while not being attached to any portion of the site marker. Further, the first end connection 88, 188, 288, 388, and/or the second end connection 90, 190, 290 may be constructed of a material that has permanent marker qualities.
The filament member may have an aspect ratio of greater than about 10:1, or other suitable dimensions, to prevent migration of the site marker from a biopsy site. Further, a site marker end cap may be ‘permanent’ materials having suitable echogenic properties such as, but not limited to, titanium, stainless steel, or platinum.
Since a site marker, such as the site marker 24, 124, 224, 324 may be deployed with the aid of a MRI, the user will visually detect when the site marker has been deployed and may confirm that the site marker has been successfully deployed in the desired location.
Although the steps of the method of deploying the site markers described herein are listed in a preferred order, the steps may be performed in differing orders or combined such that one operation may perform multiple steps. Furthermore, a step or steps may be initiated before another step or steps are completed, or a step or steps may be initiated and completed after initiation and before completion of (during the performance of) other steps.
Among other features, the medical system of the present invention localizes the target biopsy site in a manner that allows confirmation of the target biopsy site under MRI or other visualization modality, and allows increased accuracy of positioning of a biopsy device to ensure the cutting element of the biopsy device can be accurately placed at the target biopsy site. The medical system also prevents migration of site markers by reducing any predeployment plastic deformation of the site markers, thereby permitting the site markers to expand and engage the inside surfaces of a biopsy cavity with a greater force.
While the embodiments of site markers 24, 124, 224, 324 are described as having four filament members, it is understood that one or more filament members may be adequate to retain the marker in the desired biopsy cavity or other location. In addition, while the present invention has been particularly shown and described with reference to the foregoing preferred embodiments, it should be understood by those skilled in the art that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention without departing from the spirit and scope of the invention as defined in the following claims. It is intended that the following claims define the scope of the invention embodiments within the scope of these claims and their equivalents be covered thereby. This description of the invention should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. The foregoing embodiment is illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.
