1. Technical Field
The present invention relates to a medical device constructed for visualization within the body of a patient under medical imaging. More particularly, the invention relates to an echogenic medical device configured such that the location and rotational orientation of the device in the body of a patient may be observed in real time under ultrasound visualization.
2. Background Information
The ability to monitor the location and orientation of surgical instrumentation within intraluminal and extraluminal regions of the body of a patient has attained increased importance in recent years. Instruments formed of fluoroscopic and radiopaque materials are widely used to create visible regions within the body. Fluoroscopy is a technique in which an x-ray beam is transmitted through a patient to generate images of the target structure that can be displayed in a monitor. It can also be used to observe the position of instruments during diagnostic procedures. However, the use of x-ray exposes the patient to potentially harmful radiation. Additionally, health care workers must typically transport the patient to a specially-equipped radiology facility to obtain the x-ray, thereby increasing the cost and complexity of the procedure. Further, the images obtained via fluoroscopy may not achieve sufficient clarity to provide the desired level of detail to the medical professional.
Conventional endoscopy offers visualization of the immediate regions within which the endoscope is positioned by way of a video camera attached at the distal end of the endoscope. However, the video camera provides a field of view limited to only the immediate region. Surgical instrumentation within the immediate region that is obstructed by body features or by other instrumentation cannot be visualized. Similarly, instrumentation outside of the immediate region, such as outside the lumen in which the endoscope has been positioned, cannot be visualized with the endoscopic video camera.
Ultrasound imaging is another option that has been used to monitor the placement of medical instrumentation. Ultrasound imaging utilizes high frequency sound waves to create an image of living tissue. As ultrasound waves are emitted, the waves are reflected upon encountering a surface change. The reflected waves are captured to create an image, which image is displayed on a monitor in real time. Ultrasound imaging allows for monitoring of the medical devices in extraluminal regions, as well as in intraluminal regions. Such monitoring is readily used in modern medicine to guide a medical device to a target site, while at the same time minimizing the possibility of inadvertent injury to adjacent tissue resulting from a misplaced device.
Ultrasound visualization has additional favorable characteristics in that it can be performed at the bedside, and it eliminates exposure of the patient to hazardous radiation. Although ultrasound visualization provides benefits not available with other medical techniques, there are some shortcomings associated with this technique. For example, the device to be observed under ultrasound may not be easily visible at certain angles relative to the ultrasound probe. In addition, the ultrasound image may not provide sufficient detail to enable the medical professional to determine with a high degree of confidence the particular orientation of the instrument in the viewing region, such as the degree of rotation of the device in the region.
It would be desirable to provide an echogenic device that is structured such that specified features of the device can be visualized in real time when the device is positioned within the body of the patient with greater precision than available with prior art devices.
The present invention addresses the problems of the prior art. In one form thereof, the invention comprises a medical device configured for insertion into the body of a patient and ultrasound-guided movement therein to an interior target site. A shaft has a proximal portion and a distal portion, wherein the distal portion extends to a distal end. A first echogenic region at the distal portion is structured for providing a signal visible under ultrasound visualization. A second echogenic region proximal of the first echogenic region is structured and arranged for providing a signal visible under ultrasound visualization. The signal at the second echogenic region is visually distinguishable from the signal at the first echogenic region.
In another form thereof, a medical device configured for insertion into the body of a patient and ultrasound-guided movement therein to a target site is disclosed. A shaft has a proximal portion and a distal portion, wherein the distal portion extends to a distal end. An echogenic region at the distal portion comprises a plurality of geometric configurations disposed along the distal portion. At least some of the geometric configurations extend into a matrix of the shaft and define at least two wall angles1, 2. Each of the wall angles is configured and positioned to enhance an echogenicity of the geometric configuration under ultrasound visualization.
In still another form thereof, an echogenic needle is disclosed. The echogenic needle includes a shaft having a proximal portion, a distal portion extending to a distal end, first and second generally opposing longitudinal sides extending along the proximal and distal portions, and a passageway extending therethrough. The distal end defines a beveled opening communicating with the passageway. The beveled opening extends between a distal tip portion disposed along the first longitudinal side and a heel portion disposed along the second longitudinal side. A first echogenic region extending circumferentially around the shaft at the distal portion is structured for providing a signal visible along substantially the entire circumference of the shaft under ultrasound visualization. A second echogenic region extending along a length of the second longitudinal side and substantially aligned with the heel portion is structured and arranged for providing a generally linear signal visible under ultrasound examination along the second longitudinal side, and substantially not visible along the first longitudinal side.
For purposes of promoting an understanding of the present invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It should nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
In the following discussion, the terms “proximal” and “distal” will be used to describe the opposing axial ends of the device, as well as the axial ends of various component features of the device. The term “proximal” is used in its conventional sense to refer to the end of the device (or component thereof) that is closest to the operator during use of the device. The term “distal” is used in its conventional sense to refer to the end of the device (or component thereof) that is initially inserted into the patient, or that is closest to the patient during use.
As used herein, the term “echogenic” is defined as having enhanced echogenicity. Specifically, it is used to refer to a structure, or a portion of a structure, constructed or treated in a manner to provide greater reflectivity of ultrasonic waves than the structure, or structure portion, would exhibit in the absence of such construction or treatment, and/or that is capable of providing an echogenic profile relative to surrounding tissues during use of the structure in the body of a patient.
It is known in the art that materials used for medical devices, such as a needle, sheath, catheter, cannula, stylet, etc., will reflect some ultrasonic waves. However, the term “echogenic,” as used herein includes constructing or treating the device by creating, e.g., a textured, patterned, indented, angled or otherwise irregular surface including, for example, one or more dimples, divots, knurls, ridges, nubs, and the like (hereafter collectively referred to as “dimples”), each of which is known in the art to enhance echogenicity as compared to a more smooth or untreated surface for a similarly-sized/shaped object, and/or applying a material to the device capable of enhancing the echogenicity of the device when compared to a device not having the material applied thereto, and/or forming the device, or a discrete portion of the device, of a matrix suitable for enhancing echogenicity when compared to an otherwise similar device or device portion not formed of the echogenicity-enhancing matrix.
Prior art needle 10 includes an echogenic structure at its distal end. In this example, the echogenic structure comprises a pattern of dimpling 20 extending circumferentially around the distal end of the needle. It is known in the art to provide certain echogenic patterns along a medical device, such as a needle, and the pattern shown in
The known echogenic patterns, such as the pattern illustrated in the prior art needle of
It would be advantageous to have the capability of locating features of a medical device within the body of the patient with greater precision than available with prior art devices, such as the needle shown in
Without the ability to distinguish the rotational orientation of the needle as described, the medical professional may attempt to lead into the target site with the bevel heel side of the needle, instead of with the tip side. In this event, and particularly in those instances when entry is attempted at an angle to the vessel or other target structure, the stick may be unsuccessful, as the needle may deflect off the vessel or structure. When this occurs, the professional must rotate the needle in an attempt to lead with the needle tip 14. However, due to the lack of visibility on ultrasound, and in particular, an inability to distinguish the bevel heel from the distal tip on the ultrasound monitor, such rotation includes a certain element of trial and error. If sufficient rotation is not achieved, a second, or even a third attempt could also be unsuccessful. Any unsuccessful attempts add unnecessary time and effort to the procedure. Additionally, such unsuccessful attempts at entry may cause additional trauma to the patient. Even when entry is made, the professional can still not generally be certain of the exact orientation of the opening.
In this example, needle 100 includes a circumferential pattern of dimpling 120 formed at the distal end. This circumferential pattern of dimpling may be similar to dimpling pattern 20 that is shown on prior art needle 10. As stated above with regard to pattern 20 of
In the example shown in
By providing echogenic stripe 130 along a discrete longitudinal side of needle 100, in this case on the longitudinal side 134 of elongated body 102 that includes heel 108, the operator can readily distinguish one longitudinal side, or half, of the needle from the other on the ultrasound monitor. As a result, the operator is therefore able to readily determine the location of the heel. Armed with this knowledge, the operator can also readily determine the position, or more importantly, the rotational orientation of needle tip 104. The operator can then readily determine from the image on the screen whether tip 104 must be rotated in order to lead into the vessel or other structure to be penetrated by needle tip 104. If the needle must be rotated in order to maneuver tip 104 into position for initial entry, the image provided by the echogenic stripe enables the operator to determine when sufficient rotation has been carried out such that the tip is properly positioned for initial entry.
Although the respective echogenic stripe 130 and circumferential pattern 120 have been described for simplicity as comprising a series of dimples, the use if this terminology is not meant to limit the echogenic feature to a particular geometric or structural configuration. Rather, those skilled in the art are aware that echogenicity may be imparted to a substrate in other ways. Thus, for example, the surface of the device may be constructed or treated in a manner such that a textured, patterned, indented, angled, or otherwise irregular surface may be formed thereon. As stated above, the dimpling may include dimples, divots, knurls, ridges, nubs, and like structures and configurations that are capable of enhancing the echogenicity as compared to a smooth or untreated surface for an otherwise similarly-sized/shaped object.
As in the previous example, needle 200 includes a circumferential dimpling pattern 220 and an echogenic longitudinal stripe pattern 230. Longitudinal stripe pattern 230 may be provided along longitudinal side, or half, 234 of elongated body 202. One or both of patterns 220, 230 may comprise a plurality of geometrically-shaped echogenic elements. In this example, dimpling pattern 220 comprises alternating rows of echogenic dimples having different geometric shapes, and extending around the circumference of distal end 203. The alternating rows may comprise a sequential arrangement comprising a row 220a of generally circular dimples, a row 220b of generally triangular dimples, and a row 220c of generally square dimples. Similarly, longitudinal stripe pattern 230 may comprise respective longitudinal rows of generally circular dimples 230a, generally triangular dimples 230b, and generally square dimples 230c along longitudinal side 234. In this manner longitudinal side 234 may be distinguished from longitudinal side 236.
By providing respective echogenic regions 220, 230 formed of sequential rows of echogenic elements of various geometrical configurations, a suitable ultrasound image may be achieved from a wider range of insertion angles of the needle when compared to an image resulting from a single configuration.
As in the previous examples, needle 300 includes a circumferential dimpling pattern 320 and an echogenic stripe pattern 330. As in the example of
Rotating at least some of the echogenic elements around their respective axes as described enhances the echogenic signal from a respective row of the elements when compared to the same row without such rotation of the elements, thereby enhancing the visibility of stripe pattern 330.
Although the echogenic elements 120, 130, 220, 230, 320, 330 previously shown and described are either generally circular, generally triangular, or generally square, these are only examples of possible geometric configurations of the echogenic elements. Those skilled in the art will appreciate that other geometric shapes and configurations, such as hexagonal, pyramidal, etc., may be substituted for the shapes of the dimples shown and described, as long as the geometric shapes and configurations are capable of providing a suitable signal for ultrasound imaging.
Similarly, although each of the rows in the examples shown and described includes echogenic elements having the same geometric configuration, this is not required in all instances. Therefore, it is permissible to include dimples of a plurality of geometric configurations in a single row, or in each row, at least some of which may be rotated about their respective axes when compared to other elements in the row, as described above.
Needle 400 includes a first circumferential dimpling pattern 420 as before, and includes one or more sets of additional dimpling patterns. In this example, needle 400 includes second and third dimpling patterns 430, 440, respectively. Dimpling patterns 420, 430, 440 may be formed of echogenic elements of a type described above. In this example, the echogenic elements of the first circumferential pattern 420 are generally circular. The echogenic elements of the second circumferential pattern 430 are generally triangular. The echogenic elements of the third circumferential pattern are generally square. If desired, at least some of the echogenic elements may be rotated in any fashion about their axes. See, e.g., generally triangular elements 430 in the example shown. Those skilled in the art will appreciate that the specific geometric configurations of the echogenic elements are not restricted to the elements shown in this example, and may be varied as desired. Providing echogenic bands of different configurations spaced longitudinally along the length of the needle allows the operator to better determine penetration depth, and provides a scale along the shaft of the needle composed of various shapes and angles.
In addition to the dimples and related structures that may impart echogenicity to a medical device as described, echogenicity may be also imparted to the device in a manner other than by forming the echogenic elements into or onto the surface of the device in a manner described above. For example, more, or fewer, rows of dimples, etc., may be applied to form longitudinal stripes, such as stripes 130, 230, 330, and the other echogenic structures as shown and described hereinabove. In addition, the rows need not necessarily be adjacent as shown in
Those skilled in the art will appreciate that since an objective is to distinguish an amount of rotation of the device, other patterns capable of providing such orientation may be substituted. Preferably, however, all or most of the pattern will extend along a particular longitudinal side of the device. This arrangement provides a very favorable frame of reference, so that the rotational orientation of the medical device can be readily determined. Those skilled in the art will appreciate that any irregularities or other modification of the substrate should be carried out in a manner that does not adversely affect the mechanical properties of the substrate in any material fashion.
In this embodiment, rather than deforming the surface of the catheter to form the series of irregularities as described, one or more lengths of echogenic ribbon 610 may be provided along all, or a portion, of the length of catheter 600. Ribbon 610 may be formed of the same or a similar composition as catheter 600, such as a metal or a metal alloy, and deformations (e.g., dimples) are disposed along the surface of the ribbon. The deformations may be formed in the same manner as the deformations on the structures previously described, and may be dispersed along the surface of ribbon 610 in a manner such that an operator may discern the orientation of the catheter. Although catheter 600 and ribbon 610 have been described in this example as being formed of the same or a similar material, those skilled in the art will appreciate that this need not be the case, as long as suitable means (e.g., an adhesive or bonding) are provided for securing the ribbon along the surface of the catheter.
Although ribbon 610 is shown in
In addition to the foregoing, there are additional ways of providing echogenicity to a substrate of a type that will result in enhanced scatter and/or reflectance of ultrasound signals, and that may be substituted for the surface techniques described above. For example, an echogenic coating can be applied to a designated length of the substrate, such as the length of longitudinal echogenic stripes 130, 230, 330. Suitable echogenic coatings are described in, for example, U.S. Pat. Nos. 6,506,156 and 6,106,473, both incorporated by reference herein.
As yet another variation, instead of surface modification or utilizing a separate echogenic ribbon, stripe, coating, etc., the substrate may be formed to have an echogenic material incorporated into all or any designated portion of its matrix. Thus, for example, a known material for imparting echogenicity, such as glass spheres, echogenic metal or alloys (e.g., tungsten), etc., may be incorporated into the matrix during formation of the substrate, e.g., into a polymer matrix during substrate formation. Preferably, the materials (e.g., the glass spheres) will only be incorporated into the distal portion or other specifically designated portion of the substrate, and will be incorporated in a manner such that a distinct echogenic pattern is provided along the designated substrate portion, such as longitudinal side 134 (
It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.
The present patent document claims the benefit of the filing date under 35 U.S.C. §119(e) of Provisional U.S. Patent Application Ser. No. 61/590,495, filed Jan. 25, 2012, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
---|---|---|---|
61590495 | Jan 2012 | US |