The present invention relates to an endovascular medical system. In particular, the present invention is directed to an improved mechanical thrombectomy device with enhanced visibility during diagnostic imaging.
Acute ischemic stroke is caused by a thrombotic or embolic occlusion (e.g., blockage) in a cerebral artery of the brain. The occlusion is typically caused by a blood clot liberated from another part of the body which travels in an anterograde direction (in the direction of normal blood flow) through the vessel and eventually become lodged in the cerebral artery of the brain. Clots are subject to a pulsatile pressure gradient (i.e., systemic blood pressure acting on the proximal thrombus face minus the pressure from retrograde collateral blood flow at the distal thrombus face) which may compact and further wedge in place the clot within the vessel over time. In addition, some degree of biological adhesion may occur between the clot and the interior wall of the vessel.
A procedure known as a thrombectomy may be used to remove the thrombus, occlusion, blockage or clot lodged in the vessel using a mechanical device. Thrombectomy treatment or procedure is typically performed on patients within a relative short period of time following a stroke (e.g., less than an approximately 48-hour period after the occurrence of a stroke) and is best suited for large vessel occlusions typically with a diameter greater than approximately 1.0 mm. Imaging, for example, angiography, MRI, CT or CT angiography (CTA), is typically used to determine if thrombectomy treatment is suitable for that particular patient.
During the thrombectomy procedure or treatment a physician or interventionalist endovascularly introduces a guidewire through the vasculature, typically in an artery located in the groin or arm, or by direct access through the carotid artery. The guidewire is advanced through the vasculature to the target location of the clot, blockage or occlusion. Once the guidewire is properly positioned, a microcatheter with an outer diameter typically less than approximately 1.0 mm, tracks over the guidewire passing through a lumen defined axially through the microcatheter. The guidewire and microcatheter are used to cross the clot or occlusion using standard intervention techniques. While in a compressed state, a stent or mechanical thrombectomy device may be guided through the lumen of the microcatheter to the target site. Upon deployment from the microcatheter the stent or mechanical thrombectomy device automatically expands to its original enlarged state. Stents or mechanical thrombectomy devices are typically made of a biocompatible material such as stainless steel, nickel-titanium or tantalum.
Thrombectomy procedures are conducted in a cardiac catheterization laboratory of a medical facility assisted by diagnostic imaging, typically fluoroscopy (i.e., continuous x-ray imaging). During thrombectomy procedures diagnostic imaging assists the interventionalist or physician to deploy the thrombectomy device in the optimum position in the occlusion. It may also help to visualize the shape of the vessel, the location of the thrombus on the mechanical thrombectomy device and if the thrombus retracts (withdrawals proximally through the vessel) at substantially the same speed as the mechanical thrombectomy device. Diagnostic imaging may also be used to determine if there is an underlying stenosis in the vessel.
Conventional mechanical thrombectomy devices are typically constructed of Nitinol (55 w. % Nickle, balance Titanium) or other super-elastic or shape memory alloy that is deformable/compressible, yet automatically (i.e., without the need for application of any external physical force) returns (“remembers”) to its pre-deformed original shape when deployed or heated.
The shape memory alloy is subsequently set in a secondary shape by positioning on a mandrel and heating. The shape memory alloy advantageously provides a sturdy skeleton or frame while its elasticity properties allows it to recover its original shape after being deformed to be receivable within the lumen of the microcatheter. Because of the ability to set the shape of the mechanical device through mechanical constraint and heat treatment, the nitinol piece may be produced in a geometry that collapses (wraps down) to a smaller or reduced radius after being forced into the lumen of a catheter. Once the mechanical device is unsheathed from the distal end of the catheter it automatically recovers or reverts to its larger radius geometry. Despite these beneficial characteristics, one significant drawback associated with using a shape memory alloy for manufacture of the mechanical thrombectomy device is its relatively poor visibility under fluoroscopic imaging, that is, its relatively low radiopacity. To circumvent this shortcoming, conventional mechanical thrombectomy devices often are designed to incorporate additional radiopaque components (e.g., markers) such as platinum coils or gold rivets in order to improve visibility during diagnostic imaging.
The present invention is directed to an improved mechanical thrombectomy device having enhanced visibility during diagnostic imaging (e.g., fluoroscopy).
An aspect of the present invention is directed to a thrombectomy device with improved visibility during diagnostic imaging.
Another aspect of the present invention relates to an expandable mechanical device for use during a vascular medical procedure, wherein the device includes a strut having an eyelet defined therein having a geometric shape that includes at least one indent or outdent. Secured within the eyelet of the strut is a marker rivet. The geometric shape of the eyelet may include one or more indent or outdent. In addition, the indents or outdents in the eyelet may be mirror symmetrical images of one another along a longitudinal axis and/or a lateral axis. In a particular configuration, the geometric shape of the eyelet may be one of a butterfly bandage shape, a rocket shape, or a bow tie shape.
Yet another aspect of the present invention is directed to an expandable mechanical device for use during a vascular medical procedure including a strut having an outer surface and an outer diameter radial profile, wherein a recess is defined in the outer surface of the strut and extends radially inward. The device also including a U shape marker rivet received and secured within the recess of the strut. After assembly, an overall radial profile of an assembly of the strut and the U shape marker rivet is equal or less than the outer diameter radial profile of the strut alone, preferably flush with one another. In such configuration the recess may be an annular groove or an angled recess having a wedge shape radial cross-sectional profile.
Still another aspect of the present invention relates to an expandable mechanical device for use during a vascular medical procedure, the device including a plurality of struts each having an eyelet defined therein. Adjacent of the eyelets are positioned along a longitudinal axis of the mechanical device being radially offset relative to one another.
While still further another aspect of the present invention is directed to an expandable mechanical device for use during a vascular medical procedure, the device including a strut having an eyelet defined therein, the eyelet having tapered side walls forming one or more stepped layers. A marker rivet is secured within the eyelet of the strut.
Yet another aspect of the present invention relates to an expandable mechanical device for use during a vascular medical procedure, the device including a strut with an eyelet having walls defined therein. Along at least one of an outermost top edge or an innermost bottom edge of the walls of the strut having a chamfer cut.
In accordance with the present invention still another aspect is directed to an expandable mechanical device for use during a vascular medical procedure, the device including a strut having an eyelet defined therein and a strut profile, wherein the eyelet has an S shape. A complementary S shape marker rivet is secured within the S shape eyelet of the strut.
Another aspect of the present invention relates to an expandable mechanical device for use during a vascular medical procedure, the device including a single strut defined between two adjacent crowns of the expandable medical device. The single strut has a set of plural eyelets defined therein; and within each of the plural eyelets in the set a marker rivet is secured. In one aspect of the invention the plural eyelets in the set overlap one another in series, while in another aspect of the invention the plural eyelets in the set are arranged in linear series one after the other without overlap.
The foregoing and other features of the present invention will be more readily apparent from the following detailed description and drawings illustrative of the invention wherein like reference numbers refer to similar elements throughout the several views and in which:
The terms “distal” or “proximal” are used in the following description with respect to a position or direction relative to the treating physician or medical interventionalist. “Distal” or “distally” are a position distant from or in a direction away from the physician or interventionalist. “Proximal” or “proximally” or “proximate” are a position near or in a direction toward the physician or medical interventionalist. The terms “occlusion”, “clot” or “blockage” are used interchangeably.
Referring to
From the single expanded strut 205 shown post polishing depicted in
As previously mentioned above, the radiopacity and hence visibility during diagnostic imaging of the mechanical thrombectomy device may be improved by attaching or securing to the struts of the stent one or more markers made of a material having a greater radiopacity (e.g., gold, platinum or tantalum) than that of the strut.
To prevent dislodgement of the riveted marker from within the opening or eyelet of the struts of the stent, the present invention increases the contact area and overlap area, hence increasing the retention force of the rivet in the eyelet of the strut. Rather than the conventional oval cross-sectional profile of the eyelet (having no indents/recesses and/or outdents/protrusions) of prior art stents (
As an alternative to riveting radiopaque markers in the eyelets defined in the struts of the stent, the radiopacity of the mechanical thrombectomy device may be improved by crimping markers made of a radiopaque material (e.g., gold or platinum) directly to portions or segments of the strut itself. Such approach unfortunately results in an unwanted increase in the overall profile, i.e., an increase in the outer diameter (OD) and/or a decrease in the inner diameter (ID) of the crimped assembled device. With any increase in overall profile of the marker, its leading edge may disadvantageously act as a snag point during loading or re-sheathing. To overcome these problems, the outer surface or profile of the super memory alloy tubing 600 (e.g., Nitinol tubing), in accordance with the present invention, is processed to accommodate the swaging or welding thereto of the radiopaque markers without increasing the overall profile of the assembled components. Specifically, prior to laser cutting of the strut pattern, one or more annular recesses, channels or grooves 605 are defined radially inward by removing only a portion from the outer surface of the super memory alloy raw tubing 600, as illustrated in
However, as previously noted, any number of one or more annular recesses, channels or grooves 605 may be defined in the outer surface of the tubing. The annular recess, channel or groove 605 is located where the desired radiopaque marker is to be positioned. Annular recess, channel or groove 605 has a radially inward depth “r” as measured from the outermost perimeter of the tubing to the opposing bottom surface of the annular recess, channel or groove that typically varies from approximately 10% to approximately 50% of the wall thickness. The radially inward depth “r”, preferably, approximately 25-50 μm, is sufficient to accommodate a U shape or C shape marker to be crimped therein without the U shape or C shape marker extending radially outward beyond the outer diameter of the strut. Rather, the U shape or C shape marker is preferably flush with the outer diameter of the strut.
Once the material has been removed from the outer surface of the super memory alloy tubing to form the one or more annular recesses, channels or grooves the desired strut pattern may then be laser cut into the processed tubing so that following device expansion, the recesses may be aligned with the key strut locations of the device. In the exemplary radial cross-sectional profile in
An alternative configuration is depicted in
Each marker rivet is secured in place within an associated eyelet defined in the strut to avoid dislodgement during the medical procedure. Retention of the marker in the eyelet is sufficient to resist forces acting to dislodge the rivet in the direction of the inside of the strut towards the outside and from the outside of the strut towards the inside. An overhang of the marker over that of the eyelet is a typical method used to improve securement of the components with the disadvantage of creating an increase in overall profile.
It is therefore desirable to develop a still further enhanced design for secure marker retention in an eyelet defined in a strut without the undesirable trade off of increase in overall profile that makes it difficult to wrap down the mechanical device during delivery through a microcatheter. A novel design in accordance with the present invention has the tapered or angled side walls 1215d of the eyelet 1200d further defined by a plurality of steps or staggered tapered layers defined in the strut 1205d, (
Mechanical thrombectomy procedures are typically performed under fluoroscopy and radiopaque markers on the mechanical thrombectomy device provide the interventionalist with a visual indication of the position and expansion/crimped state of a device during the medical procedure. By way of illustrative example, information provided by visual indicators of use to an interventionalist during the medical procedure may include: position of the device in the microcatheter on delivery; expansion of the device on deployment; changes in expansion of the device on retrieval.
Radiopaque markers arranged in clearly defined rings around the circumference at several locations along the mechanical device provide observable information to the physician or interventionalist during the medical procedure. Typically, during a procedure there are two fluoroscopic views used by the physician or interventionalist, namely, the anterior-posterior view (parallel with a patient's torso) and lateral view (parallel with patient side). Distinguishing the ring a particular identified marker belongs to is potentially beneficial and may be a challenge for the physician or interventionalist.
The present invention seeks to improve the visibility of the marker and geometrically differentiate markers in each ring around the circumference to readily discern which marker ring each individually identified marker belongs and hence allow the physician or interventionalist to determine the expansion/crimped state of the device at the discrete location along the length of the device the markers are located.
Differentiation or identification of the marker during imaging is achieved, in accordance with the present invention, without increasing overall profile of the mechanical device or negatively impacting its performance (e.g., greater delivery force when advanced through the microcatheter). A top view in
The present inventive features illustrated and described can be use in a mechanical thrombectomy procedure but is also suitable for use in other neurovascular or endovascular medical procedures.
Thus, while there have been shown, described, and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions, substitutions, and changes in the form and details of the systems/devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the invention. For example, it is expressly intended that all combinations of those elements and/or steps that perform substantially the same function, in substantially the same way, to achieve the same results be within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated. It is also to be understood that the drawings are not necessarily drawn to scale, but that they are merely conceptual in nature. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
Every issued patent, pending patent application, publication, journal article, book or any other reference cited herein is each incorporated by reference in their entirety.
Number | Name | Date | Kind |
---|---|---|---|
5906606 | Chee et al. | May 1999 | A |
6004310 | Bardsley et al. | Dec 1999 | A |
6022374 | Imran | Feb 2000 | A |
6293966 | Frantzen | Sep 2001 | B1 |
6315757 | Chee et al. | Nov 2001 | B1 |
6334871 | Dor | Jan 2002 | B1 |
6391037 | Greenhalgh | May 2002 | B1 |
6503271 | Duerig et al. | Jan 2003 | B2 |
6620192 | Jalisi | Sep 2003 | B1 |
6702782 | Miller et al. | Mar 2004 | B2 |
6855161 | Boylan et al. | Feb 2005 | B2 |
6863685 | Davila et al. | Mar 2005 | B2 |
6929635 | Shelso | Aug 2005 | B2 |
6955685 | Escamilla et al. | Oct 2005 | B2 |
7063707 | Bose et al. | Jun 2006 | B2 |
7335227 | Jalisi | Feb 2008 | B2 |
7708771 | Chuter et al. | May 2010 | B2 |
7766049 | Miller et al. | Aug 2010 | B2 |
7810223 | Hemerick et al. | Oct 2010 | B2 |
8021418 | Gerberding et al. | Sep 2011 | B2 |
8313503 | Cully et al. | Nov 2012 | B2 |
8337520 | Cully et al. | Dec 2012 | B2 |
8500786 | Simpson et al. | Aug 2013 | B2 |
8500787 | Simpson et al. | Aug 2013 | B2 |
8545548 | Lorenzo | Oct 2013 | B2 |
8623071 | Lundkvist et al. | Jan 2014 | B2 |
8852205 | Brady et al. | Oct 2014 | B2 |
8926560 | Dinh et al. | Jan 2015 | B2 |
8974517 | Pelton et al. | Mar 2015 | B2 |
9011374 | Lentz et al. | Apr 2015 | B2 |
9232992 | Heidner | Jan 2016 | B2 |
9232997 | Sugimoto et al. | Jan 2016 | B2 |
9445829 | Brady et al. | Sep 2016 | B2 |
9532792 | Galdonik et al. | Jan 2017 | B2 |
9532873 | Kelley | Jan 2017 | B2 |
9533344 | Monetti et al. | Jan 2017 | B2 |
9539011 | Chen et al. | Jan 2017 | B2 |
9539022 | Bowman | Jan 2017 | B2 |
9539122 | Burke et al. | Jan 2017 | B2 |
9539382 | Nelson | Jan 2017 | B2 |
9549830 | Bruszewski et al. | Jan 2017 | B2 |
9554805 | Tompkins et al. | Jan 2017 | B2 |
9561125 | Bowman et al. | Feb 2017 | B2 |
9572982 | Burnes et al. | Feb 2017 | B2 |
9579484 | Barnell | Feb 2017 | B2 |
9585642 | Dinsmoor et al. | Mar 2017 | B2 |
9615832 | Bose et al. | Apr 2017 | B2 |
9615951 | Bennett et al. | Apr 2017 | B2 |
9622753 | Cox | Apr 2017 | B2 |
9636115 | Henry et al. | May 2017 | B2 |
9636439 | Chu et al. | May 2017 | B2 |
9642675 | Werneth et al. | May 2017 | B2 |
9655633 | Leynov et al. | May 2017 | B2 |
9655645 | Staunton | May 2017 | B2 |
9655989 | Cruise et al. | May 2017 | B2 |
9662129 | Galdonik et al. | May 2017 | B2 |
9662238 | Dwork et al. | May 2017 | B2 |
9662425 | Lilja et al. | May 2017 | B2 |
9668898 | Wong | Jun 2017 | B2 |
9675477 | Thompson | Jun 2017 | B2 |
9675782 | Connolly | Jun 2017 | B2 |
9676022 | Ensign et al. | Jun 2017 | B2 |
9692557 | Murphy | Jun 2017 | B2 |
9693852 | Lam et al. | Jul 2017 | B2 |
9693885 | Lorenzo | Jul 2017 | B2 |
9700262 | Janik et al. | Jul 2017 | B2 |
9700399 | Acosta-Acevedo | Jul 2017 | B2 |
9717421 | Griswold et al. | Aug 2017 | B2 |
9717500 | Tieu et al. | Aug 2017 | B2 |
9717502 | Teoh et al. | Aug 2017 | B2 |
9724103 | Cruise et al. | Aug 2017 | B2 |
9724526 | Strother et al. | Aug 2017 | B2 |
9750565 | Bloom et al. | Sep 2017 | B2 |
9757260 | Greenan | Sep 2017 | B2 |
9764111 | Gulachenski | Sep 2017 | B2 |
9770251 | Bowman et al. | Sep 2017 | B2 |
9770577 | Li et al. | Sep 2017 | B2 |
9775621 | Tompkins et al. | Oct 2017 | B2 |
9775706 | Peterson et al. | Oct 2017 | B2 |
9775732 | Khenansho | Oct 2017 | B2 |
9788800 | Mayoras, Jr. | Oct 2017 | B2 |
9795391 | Saatchi et al. | Oct 2017 | B2 |
9801980 | Karino et al. | Oct 2017 | B2 |
9808599 | Bowman et al. | Nov 2017 | B2 |
9833252 | Sepetka et al. | Dec 2017 | B2 |
9833604 | Lam et al. | Dec 2017 | B2 |
9833625 | Waldhauser et al. | Dec 2017 | B2 |
20040088039 | Lee et al. | May 2004 | A1 |
20040143317 | Stinson et al. | Jul 2004 | A1 |
20040167619 | Case | Aug 2004 | A1 |
20060064151 | Guterman | Mar 2006 | A1 |
20060212068 | Boylan et al. | Sep 2006 | A1 |
20070266542 | Melsheimer | Nov 2007 | A1 |
20070276476 | Llanos et al. | Nov 2007 | A1 |
20080281350 | Sepetka | Nov 2008 | A1 |
20090005853 | Osman | Jan 2009 | A1 |
20100324649 | Mattsson | Dec 2010 | A1 |
20110245806 | Patterson | Oct 2011 | A1 |
20120089219 | Fircho et al. | Apr 2012 | A1 |
20120283768 | Cox et al. | Nov 2012 | A1 |
20130319603 | Wu | Dec 2013 | A1 |
20140135812 | Divino et al. | May 2014 | A1 |
20140200607 | Sepetka et al. | Jul 2014 | A1 |
20150174363 | Sutermeister et al. | Jun 2015 | A1 |
20150305826 | Loganathan et al. | Oct 2015 | A1 |
20160001040 | Yamaguchi et al. | Jan 2016 | A1 |
20160008152 | Green | Jan 2016 | A1 |
20160015402 | Brady et al. | Jan 2016 | A1 |
20160022292 | Stigall et al. | Jan 2016 | A1 |
20160058971 | Leeflang et al. | Mar 2016 | A1 |
20160354584 | Hanson et al. | Dec 2016 | A1 |
20170007264 | Cruise et al. | Jan 2017 | A1 |
20170007265 | Guo et al. | Jan 2017 | A1 |
20170020670 | Murray et al. | Jan 2017 | A1 |
20170020700 | Bienvenu et al. | Jan 2017 | A1 |
20170027640 | Kunis et al. | Feb 2017 | A1 |
20170027692 | Bonhoeffer et al. | Feb 2017 | A1 |
20170027725 | Argentine | Feb 2017 | A1 |
20170035436 | Morita | Feb 2017 | A1 |
20170035567 | Duffy | Feb 2017 | A1 |
20170042548 | Lam | Feb 2017 | A1 |
20170049596 | Schabert | Feb 2017 | A1 |
20170056616 | Leeflang et al. | Mar 2017 | A1 |
20170071737 | Kelley | Mar 2017 | A1 |
20170072452 | Monetti et al. | Mar 2017 | A1 |
20170079671 | Morero et al. | Mar 2017 | A1 |
20170079680 | Bowman | Mar 2017 | A1 |
20170079766 | Wang et al. | Mar 2017 | A1 |
20170079767 | Leon-Yip | Mar 2017 | A1 |
20170079812 | Lam et al. | Mar 2017 | A1 |
20170079817 | Sepetka et al. | Mar 2017 | A1 |
20170079819 | Pung et al. | Mar 2017 | A1 |
20170079820 | Lam et al. | Mar 2017 | A1 |
20170086851 | Wallace et al. | Mar 2017 | A1 |
20170086996 | Peterson et al. | Mar 2017 | A1 |
20170095259 | Tompkins et al. | Apr 2017 | A1 |
20170100126 | Bowman et al. | Apr 2017 | A1 |
20170100141 | Morero et al. | Apr 2017 | A1 |
20170100143 | Grandfield | Apr 2017 | A1 |
20170100183 | Iaizzo et al. | Apr 2017 | A1 |
20170113023 | Steingisser et al. | Apr 2017 | A1 |
20170147765 | Mehta | May 2017 | A1 |
20170151032 | Loisel | Jun 2017 | A1 |
20170165062 | Rothstein | Jun 2017 | A1 |
20170165065 | Rothstein et al. | Jun 2017 | A1 |
20170165454 | Tuohy et al. | Jun 2017 | A1 |
20170172581 | Bose et al. | Jun 2017 | A1 |
20170172766 | Vong et al. | Jun 2017 | A1 |
20170172769 | Ta et al. | Jun 2017 | A1 |
20170172772 | Khenansho | Jun 2017 | A1 |
20170189033 | Sepetka et al. | Jul 2017 | A1 |
20170189035 | Porter | Jul 2017 | A1 |
20170215902 | Leynov et al. | Aug 2017 | A1 |
20170216484 | Cruise et al. | Aug 2017 | A1 |
20170224350 | Shimizu et al. | Aug 2017 | A1 |
20170224355 | Bowman et al. | Aug 2017 | A1 |
20170224467 | Piccagli et al. | Aug 2017 | A1 |
20170224511 | Dwork et al. | Aug 2017 | A1 |
20170224953 | Tran et al. | Aug 2017 | A1 |
20170231646 | Epstein et al. | Aug 2017 | A1 |
20170231749 | Perkins et al. | Aug 2017 | A1 |
20170252064 | Staunton | Sep 2017 | A1 |
20170259034 | Leeflang et al. | Sep 2017 | A1 |
20170265983 | Lam et al. | Sep 2017 | A1 |
20170281192 | Tieu et al. | Oct 2017 | A1 |
20170281331 | Perkins et al. | Oct 2017 | A1 |
20170281344 | Costello | Oct 2017 | A1 |
20170281909 | Northrop et al. | Oct 2017 | A1 |
20170281912 | Melder et al. | Oct 2017 | A1 |
20170290593 | Cruise et al. | Oct 2017 | A1 |
20170290654 | Sethna | Oct 2017 | A1 |
20170296324 | Argentine | Oct 2017 | A1 |
20170296325 | Marrocco et al. | Oct 2017 | A1 |
20170303939 | Greenhalgh et al. | Oct 2017 | A1 |
20170303942 | Greenhalgh et al. | Oct 2017 | A1 |
20170303947 | Greenhalgh et al. | Oct 2017 | A1 |
20170303948 | Wallace et al. | Oct 2017 | A1 |
20170304041 | Argentine | Oct 2017 | A1 |
20170304097 | Corwin et al. | Oct 2017 | A1 |
20170304595 | Nagasrinivasa et al. | Oct 2017 | A1 |
20170312109 | Le | Nov 2017 | A1 |
20170312484 | Shipley et al. | Nov 2017 | A1 |
20170316561 | Helm et al. | Nov 2017 | A1 |
20170319826 | Bowman et al. | Nov 2017 | A1 |
20170333228 | Orth et al. | Nov 2017 | A1 |
20170333236 | Greenan | Nov 2017 | A1 |
20170333678 | Bowman et al. | Nov 2017 | A1 |
20170340383 | Bloom et al. | Nov 2017 | A1 |
20170348014 | Wallace et al. | Dec 2017 | A1 |
20170348514 | Guyon et al. | Dec 2017 | A1 |
Number | Date | Country |
---|---|---|
10235868 | Feb 2004 | DE |
2438891 | Apr 2012 | EP |
Entry |
---|
Co-Pending, co-owned U.S. Appl. No. 16/441,389, filed Jun. 14, 2019. |
Number | Date | Country | |
---|---|---|---|
20200390459 A1 | Dec 2020 | US |