CA2223572A1

CA2223572A1 - Identification and locating transponder for implants

Info

Publication number: CA2223572A1
Application number: CA002223572A
Authority: CA
Inventors: Terry R. Knapp; Elizabeth Mary Belsey
Original assignee: Individual
Current assignee: Lipomatrix Inc
Priority date: 1995-06-05
Filing date: 1996-03-27
Publication date: 1996-12-12
Also published as: WO1996039099A1; EP0830105A1; AU5497196A; US5725578A; BR9608971A; JPH11500335A

Abstract

A passive transponder (28) may be encoded with a binary number or code of 64 bits or more and then associated with or mounted to virtually any implant intended for implantation in a human including temporary implants such as drug release implants (130) and organ displacement devices (134). After implantation, the transponder's code may be conveniently read with a hand-held electromagnetic reader (34) which may merely be brought within proximity of the transponder (28). The encoded transponder (28) may thus be read in a non-invasive procedure and without the use of any sophisticated or potentially harmful medical equipment or technology such as X-rays. Where the position of the implant in the human changes over time, or is otherwise unknown to attending medical personnel, the transponder and implant can be located by using a strength of signal indicator on the electromagnetic reader (34). The information encoded in the transponder may simply be a tag for locating the implant, or may correspond to patient demographics and implant data to aid in tracking the implant and patient for medical as well as legal reasons.

Description

, CA 02223~72 1997-12-04 TITLE: Temporary implant with transponder and methods for locating and identifying DESCRIPTION

Background and Summarv of the Invention With the advance of medical technology, there are a number of medical prostheses and devices which are implantable in humans for re-constructive and/or cosmetic purposes. These include breast implants; penile implants; musculature and other soft tissue implants; pace makers; valves; artificial joints and limbs such as knees, shoulders, legs, fingers, etc.; pins; screws; plates; rods; nails and other braces and supports. In order to ensure the continued safety and health of patients receiving these implants, the Safe Medical Device Act of 1990 has been enacted which dictate that manufacturers of Class III implantable medical devices institute a device registry for tracking of their devices, notification of patients, and otherwise monitoring these implants after they have been placed in a patient. Compliance with this Act has been proposed through a method of tracking which required the surgeon who implants the device to complete and return a form or card with patient demographic data and implant data to the manufacturer or to a third party registry service. This method required careful accumulation of data by a surgeon or his staff as well as secure inventory control procedures in order to ensure that the date is properly associated with the correct implant. Additionally, there is a risk of loss ~_ ~

A~.~.ENDED S~

CA 02223~72 1997-12-04 W096~9099 PCT~P96/01349 of the data entirely resulting from misdirected or lost communications. Furthermore, Access to this data can be impeded in the event of an emergency situation or other circumstAnceC which interfere with a patient's ability to 5 recall or report the proper information which me~ OAl per~o~nel may then use to access the registry and data contA~ned therein.
The issues described above wlth respect to more permanent types of medical ~lG:j Lhesis and devices are lO very similar for devices temporarily implanted for therapeutic and other pUL ~oses, including drug release implants and organ displacement devices. An example of a drug release implant is an implant for releasing a birth control drug over a period of time, such as six months or 15 a year. An organ displacement device is a device which is implanted into a patient, either before or after the device has been inflated with a filler material, to separate healthy organs from ~s~as~ or o~heL.~ise afflicted organs which are undergoing therapeutic 20 treatment, such as radiation therapy. As with permanently implanted medical yLos~hec~ and devices, temporary implants are sub~ect to re~ection, infection, and a host of other medical complications. For temporary implant patients, the ready availability of information 25 relating to the temporary implant and the medical procedure utilized would be very helpful in treating the patient as well as in trAck~ ng and monitoring the patients pLoyLess. In emergency situations, access to this data may well be critical to ~LU~JeL Al Agnoc~ and 30 treatment, especially if a disorder relating to the temporary implant is what causes the me~cAl emergency.
There have been some suggestions in the prior art of marking the implants themselves with, for example, a radiopaque marker or other marker which contains the 35 information relating to the implant. Ideally, this data could then be viewable by X-ray or some other non-inva-- - -CA 02223~72 1997-12-04 W O 96~9099 PCTAEP96/01349 sive manner. However, there are difficulties with these prior art approaches. First of all, a breast implant with a radiopaque marker would at least partially obscure or mask tissue which is desired to be viewed in order to 5 detect artifacts relating to tumors or the like for diag-nOQ~ ns~ c~n~er. Obviously, this is highly undesirable as the ~nc~nce of breast c~nC~r presents a significant risk to many females. Additionally, repeated exposure to X-ray is not generally conc~red healthful or desirable 10 and represents at least an added in~unv~lience ent~ ng some degree of expense to recall or ACcecs the implant data. Therefore, radiopaque markers have not been viewed as a suitable long-term solution to this problem.
In order to solve these and other problems in the 15 prior art, and in order to provide a ~o.lv2..ient, fool proof marker ~QQor~Ated with or secured to the implant itself, and yet readable in a non-invasive manner, the inventorS herein have s~ccee~ in desl gn~ n~ and dev~l ~r~ ng an implant which i~u~ulates a passive 20 transponder which may be en~,o~G~ and subsequently ~c~QQe~ with a hand held electromagnetic reader in a quick and ~n~Yp~ncive ~.~ed~re. The passive transpon~r may be secured to the implant by any ~onve--ient means.
For example, in a breast implant, the multi-layered shell 25 for the implant may be laminated around the transpon~-to thereby be permanently and securely fixed to the implant. The transpon~er may be laminated in the Q~ all of the shell, or between layers whlch comprise the seal patch which is applied to the shell to seal the 30 mandrel open~ng. Similarly, the tranSpon~er may be laminated onto the surface of most other implants in an unobtrusive location. In some other implants, the transpon~er may be inserted into a hole or inlay and -~e~le~ in place. Other a~ce~able methodologies for 35 ~ssn~ ting the transpon~r with the implant include ut~l~ 7~ng a non-absorbable "string and bas~et" tether or CA 02223~72 1997-12-04 W O 96~9099 PCTrEP96/01349 by locating the transponder according to an "adjacent slte" stAn~rd. This adjacent site may be in very close proximity to the implant or in a stAndArdized location that may be device specific.
As passive transronAers are commercially available in a cylindrical shape sized at 2 mm in diameter and 11 mm in length, the patient will not sense any discom-fort or even the pre-C~nce of the transponA~r. Also, the transponAer may be encoA~A with any suitable enco~ng 10 scheme. A commercially available transronAer presently provides for the storage of up to 64 binary bits of data.
This data cApArity may accommodate the direct storage of much, if not all, of the information desired to be re-corded and maintAi neA in a device registry. Furthermore, 15 the storage cArAc1ty of the transponA~-r is expected to be increased as further development occurs over time. Al-ternately, a number, collection of numbers, combination of numbers and letters, or other indirect code may be s~o~ed which after reA~1~g may be used to A~C~ a data 20 bank which itself contains the desired information. Of course, if information is directly stored in the implant, it becomes immediately available upon reAAing the tran-sponA?r. This provides ready Acc~ce to information in emeLyen~y situations. However, with the widespread 25 avAilAh1l1ty, ACc~csibility~ and use of computers over telecommunications networks including tel~rhone lines, it is not generally considered to be unduly limiting to provide that the code read from the transponA~r be then used to Acces~ an appropriate data bank in order to ob-30 tain the patient demograph1r~ manufacturer's name, dateof manufacture, surgeon's name, date of implantation, etc.
A companion hand held electromagnetic reader is also commercially avAi ] ~hl e which emits a low frequency 35 magnetic field to activate the passive trAnCponA~r and thereby cause it to transmit its çncoAeA data to the CA 02223~72 1997-12-04 W096/39099 PCT~P96/01349 reader. With this particular commercial device, no bat-tery or other source of electrical power need be included in the passive transronAe~. This further r~ ce-c the size required for the transponder and renders it particu-5 larly suitable to this application. Moreover, in thecase of implants that are susceptible to movement within the patient over a period of time, or where the atten~ ng me~rAl perCo~n~l are uncertain as to the position of the implant within the patient's body, the electromagnetic 10 reader can be utilized for locating the transron~er and implant by monitoring the strength of signal indicator provided with the reader.
While the principal advantages and features of the present invention have been described above, a more com-15 plete and thorough understA~ng of the invention may beattA~nA~ by referring to the drawings and descriptlon of the preferred embodiment which follow.

CA 02223~72 1997-12-04 W096~9099 PCT~P96/01349 8rief Descri~tion of the Drawinas Figure 1 is a perspective view of a breast implant contA~n~ng a passive transpon~r with a hand held reader in position to read the ~nco~P~ data cont~i nP~ therein;
Figure 2 is a partial cross-sectional view of the transpon~Pr as laminated between the multiple layers of a seal patch for a breast implant;
Flgure 3 is a perspective view of a ~e~o~alis muscle implant with a passive transpon~er mounted there-10 in;
Figure 4 is a perspective view of a soft chin im-plant with passive transpon~er mounted therein;
Figure 5 is a perspective view of a rigid chin implant with a passive transponder mounted therein;
Figure 6 is a ~eLx~ective view of a nipple trans-plant with a passive transponder mounted therein;
Figure 7 is a pe~s~e~Live view of an otoplasty implant with a passive transpo~r mounted therein;
Figure 8 is a ~Lx~e~Live view of a pen~ 19 im-20 plant, surgically implanted, with a passive transpon~rmounted therein;
Figure 9 is a top view of a pace maker with a pas-sive tranSpon~er mounted theLeo--;
Figure 10 is a top view of a heart valve with a 25 passive transponder mounted to the edge thereof;
Figure 11 is a peL~ecLive view of a total knee ~oint prosthesis with a passive transponder mounted thereon;
Figure 12 is a peLs~e~Live view of a shoulder ar-30 throplasty system wlth a passive transpon~er mountedtherein;
Figure 13 is a partial cross-sectional view of a passive transponder inlaid into and below the surface of an implant:

CA 02223~72 1997-12-04 W O 96~9099 PCTAEP96/01349 Figure 14 is a perspective view of a femoral fixa-tion system implanted in a femur with a passive trans-ron~r mounted thereto:
Figure 15 is a perspective view of an orthopedic S nailing system with a passive trans~sn~r mounted there-in;
Figure 16 is a perspective view of a finger joint ~LO~ Lhe~ic with a passive transrsnAer mounted therein;
Figure 17 is a perspective view of a craniomaxil-10 lofacial plating system with a passive transpon~er mount-ed therein;
Figure 18 is a perspective view of still another plating system with a passive tran~ pr mounted there-in;
Figure 19 is a partial cross-sect~on~l view of a typical implant with a passive transpo~r mounted within a cored hole drilled therein;
Figure 20 is a perspective view of a drug release implant with a passive transrsn~r affixed thereto; and Figure 21 is a partially cu~a ay view of an organ d~srlA~ement device with a passive transpon~r mounted therein.

Detailed Descri~tion of the Preferred Embodiment As shown in Figure 1, a breast implant 20 has been 25 implanted in a female's breast 22 and includes a silicone shell 24 inflated with an ap~lu~ iate fill material 26.
At the posterior side of the implant 20 is shown the transpon~?r 28 which has been laminated between ad~acent layers 30, 32 of the shell 24. Transpo~ 28 may be any 30 passive transpsn~Dr such as a Trovan Model ID100 avail-able from Electronic Identification Systems Ltd. of Santa Barbara, California. This particular transpon~r is designed to be environmentally ~dep~ndent and suitable for operation while being directly submerged in liquids.
35 Furthermore, it may be read spherically from any direc-CA 02223~72 1997-12-04 W096~99 PCT~P96/01349 tion through most materials, and including most impor-tantly those materials comprising implants for the human body. The transponAPr may be directly ~nc-o~e~ with 64 binary bits or more of data to provide almost one tril-5 lion possible different code combinations. The limit ofdata ,e~,ded is a function of the further ~oy~ess and development of ele~lollic memory terhnology. It is anticipated that FDA a~oval will be forthcoming for its use as part of the invention ~lcclo-s~A and claimed lO herein.
A hand held reader 34 is also shown in Figure l and may be a Trovan Model LID500, or other suitable de-vice. Its principle of operation includes emitting a low frequency magnetic field for activating the passive tran-15 spqnA-r 28. As such, transronA~r 28 has no power source and instead derives the energy nePA~A for its operation from the magnetic field generated by the reader 34. This permits the tranSponA~r 28 to have a virtually unlimited life span. The hand held reader 34 is shown ronnected to 20 a Aec~A~r controller 36 which ~cce-cce-s a data bank 38 in ~-1~'~ to the deLec~ed code contA1neA within transpond-er 28 to thereby Acr-~ss such data which has been stored correspond1ng to transpon~er 28. Alternately, as men-t1o~eA above, the hand held reader 34 may be used to ac-25 cess the code contAlne~ within tranxl~ Aer 28 and then other means used to ~ccesc a data bank for the retrieval of the desired information. Such means might include the use of a telepbone and modem to Acr~cs a registry con-tAlne~ in a yeGy~a~hically centrally located site.
As shown in Figure 2, the transpon~-r 28 may be laminated between ad~acent layers 40, 42 of the seal patch 44 which is commonly used to seal the mandrel open-ing 46 in a shell 48 of a breast implant 50. For other implants, convenient mounting locations may be readily 35 determined with due consideration given to avoiding dis-CA 02223~72 1997-12-04 W O 96~9099 PCT~EP96tO1349 comfort to the patient as well as optimizing readability of the transpo~Aer with the hand held reader.
As shown in Figure 3, a pectoralis muscle implant 52 may conveniently have a passive transpo~r 54 con-5 tA1nP~ therein. The passive transpon~er 54 may be moldedin place, or a hole or inlay drilled for placement of the implant, after which the implant surface may then be ref~ n~ ~h~ .
As shown in Figures 4 and 5, a soft chin implant 10 56 or a hard chin implant 58 may also have a passive transpo~de- 60, 62 mounted therein. As shown in Figure 6, a nipple implant 64 has a passive transpo~d~r 66 mounted internally. In all of these transplants, the mounting of the passive transpon~Dr is achieved to pro-15 vide minimal discomfort or sensation to the patient, aswell as to avoid interference with the cosmetic appear-ance of the implant. As shown in Figure 7, an otoplActy implant 68 may have a passive transpon~Pr 70 mounted therein. As shown in Figure 8, a penile implant 72 may 20 have a passive transpon~er 74 mounted therein.
As shown in Figure 9, a pace maker 76 may also have a passive transpon~er 78 mounted either on its sur-face or below the protective metal casing thereof. The inventors have found that rPAA'I ng of the passive tran-25 spon~er by the hand held reader may be achieved even whenthe transpon~P,r is obscured by metallic surfaces. As shown in Figure 10, a heart valve 80 may have a passive transpon~er 82 mounted to its edge in order to avoid interference with the operability thereof, or fixation 30 thereof.
As shown in Figures 11 and 12, a total knee joint prosthesis 84 or a shoulder prosthe~is 86, either one of which includes a ma~ority of parts made from titanium or the like, may also ~ollv~liently carry a passive trans-35 ponder 88, 90.

CA 02223~72 1997-12-04 W096/39099 PCT~P96/01349 As shown in Figure 13, the passive transpon~r 92 may be placed within a trough 94 or the like and covered with a QeAl~nt 96 so that the surface of the transpon~er 98 is uninterrupted and smooth as is desirable in many 5 tr~ncpon~?rs.
As shown in Figures 14 and 15, a femoral fixation implant 100, or an orthopedic n~ ng system 102 may .~v~,liently have a passive transron~r 104, 106 inlaid therein. As shown in Figure 16, a finger joint ~lG~he-10 sis 108 may also have a passive transpon~or llO locatedin a position which does not interfere with the movable joint portion 112 of the prosthes~ 108. As shown in Figures 17 and 18, a craniomaxillofacial plating system 114 or any other plating system 116 may also ~ eniently 15 include a passive trAneronAor 118, 120. As an alterna-tive to the inlay mounting shown in Figure 13, a hole 122 may be drilled in any ~onv~.~ient location of an implant 124 and the passive transponder 126 inserted therein and ~alo-d in place by seAl~r 128, with the outer surface of 20 s~ler 128 being finished to provide a smooth surface on implant 124, as shown in Figure 19.
A passive transpon~er may also be utilized with implants inte~ed for temporary implantation in humans including, but not limited to, drug reloAso implants and 25 organ displacement devices. As shown in Figure 20, a drug release implant 130 may have a transp~nder 132 mounted thereto in such a manner that transronAQr 132 does not interfere with the controlled role~e of a drug from the implant 130. The transpo~or 132 may contain a 30 code relatlng to information such as the date of implantation, the type of drug cont~ no~ in the implant 130, and the date when the implant 130 should be removed or replaced. As shown in Figure 21, an organ displacement device 134 may have a passive transpondor 35 136 affixed to the interior surface of the device such that the transpondor 136 does not interfere with the CA 02223~72 1997-12-04 W096~90g9 PCT~P96/01349 inflation or deflation of the organ displacement device 134, or wlth the therapeutic process for which the device 134 is being used. In this case, the passive transp~nd~r 136 may contain a code relating to information such as 5 the date of implantation and the particular type of organ displacement device, as well as information pert~ n~ ng to the history of the therapy undergone by the patient in which the organ displacement device is implanted.
Altho~gh all of the implants ment~o~eA above have 10 been described as having a passive transronAPr mounted to the interior or the exterior of the part~rl~lAr device, other ac~ey~able methodologies for Assoc~Ating the transponA~r with the implants are avA~lAhle. Examples of these alternative methods include ut~l~ 7~ ng a non-15 absorbable string and basket tether or by locating the trAncronA~r according to an ad~acent site StAnAArd. In the case of uff l~7~g the ad~acent site stAnA~rd, the slte may be in close prox$mity to the implant or in a stAnAArdized location that may be device specific.
In addition to uff l~ 7~ ng a passive transro~Aer in con~unction with an implant to identify the part~cl~lAr implant and retrieve data relating to the implant and patient, the passive transponder can also be ut~l~ 7eA to locate the particular implant in cases where the implant 25 is su~e~ible to movement within the patient's body overa period of time, or where the att~nA~ng meA~cAl pel~o~-el are otherwise u,~ aln as to the position of the implant within the patient's body. For example, where a drug release implant is implanted into a patient 30 for several months or years, the implant may move from the position in the patient's body where the implant was originally plA~-~A. Hence, the part~lllAr location of the implant must be ascertA~neA before the implant can be removed. Similarly, an organ displacement device may be 35 susceptible to movement within a patient's body during the period of time between s~cc~ssive therapeutic CA 02223~72 1997-12-04 W096~9099 PCT~P96/01349 treatments. Because these devices may be inflated in situ after implantation but prior to a therapeutic treatment, and then deflated thereafter, the precise location of the organ displacement device, as well as an 5 inflation/deflation valve associated therewith, must be ascert~neA prior to performing these proceA~res, as well as prior to removal of the device.
In these cases, the passive transponAPr ~scoc~ated with an implant can be ut~l~ 7eA to locate the specific lO positlon of the implant in the patient's body. 8y ut~ ng an electromagnetic reader having a strength-of-signal meter, the reader can be used to externally scan over a portion of the patient's body where the implant is generally e~yec~ed to be located. By referring to the 15 strength-of-Q~g~l meter on the electromagnetic reader, the specific location of the implant can be ascert~ineA.
This specific location will correspond to the location on the patient's body where the electromagnetic reader generated the s~o.~yest read s~gn~l. In other words, as 20 the electromagnetic reader appro~ch~s the external position of the body that corresponds to the internal location of the implant and transponA~r, the ~ LL el~yLh of the read s~gnAls generated by the electromagnetic reader, and ~ nA ~ c~ted thereon, will increase. As the reader 25 moves away from this external position of the body, the 51,1e~ h of the read signals will decrease. In this manner, the electromagnetic reader and transronAer can be ut~ 1~ 7eA to find an implant. Where the transpon~r is used in this manner for the purpose of subsequently 30 locating the position of the implant in the patient's body, the transpo~A~r may be en~n~A with a simple code or tag solely for this purpose, or may additionally be e~coA~A to identify particular information about the implant and patient, as described above.
As disclosed herein, a wide variety of implants made of all sorts of material may conveniently include a .
CA 02223~72 1997-12-04 W O 96/39099 PCTrEP96/01349 passive transpon~r which may be implanted, and then read by the hand held reader. This compatibility and ease of operation permits the use of a passive transponder with virtually any implant. The inventors have disclosed 5 herein a representative sample of such implants. Howev-er, the scope of the present invention is broad enough to encompass any implant presently known to the inventors hereln.
There are various changes and modifications which 10 may be made to the invention as would be apparent to those skilled in the art. However, these changes or modifications are included in the t~ch~g of the disclo-sure, and it is int~A~ that the invention be limited only by the scope of the claims app~nA~A hereto.

Claims

1. An implant intended for human implantation, said implant including a transponder (132) associated therewith so that said transponder is implanted as said implant is implanted, said implant having means for being encoded with a unique identifier so that said transponder may be readily identified after implantation by reading said unique identifier characterised in that the implant is for temporary human implantation and the unique identifier enables data relating to the date of implant and the date of removal or replacement of the implant to be readily obtained.

2. An implant as claimed in claim 1, wherein said transponder (132) has means for its unique identifier to be read with a non-invasive protocol (34).

3. An implant as claimed in claim 2, wherein said transponder has means for its unique identifier to be read electromagnetically.

4. An implant as claimed in claim 3, wherein said transponder (132) has means for being energized by a remote reader (34) thereby obviating a need for a battery to be contained in said transponder.

5. An implant as claimed in any one of claims 1 to 4, wherein said unique identifier is a binary number having up to 64 bits.

6. An implant as claimed in any one of the preceding claims, wherein said temporary implant is a drug release implant (130).

7. An implant as claimed in any one of claims 1 to 5, wherein said temporary implant is an organ displacement device (134).

8. An implant as claimed in any one of the preceding claims, wherein said transponder (136) is mounted to said implant.

9. An implant as claimed in any one of the preceding claims, wherein the unique identifier has a unique tag so that said tag may be read after implantation to locate said transponder.

10. An implant as claimed in claim 9, wherein said tag is a binary number.

11. An implant as claimed in claim 10, wherein said binary number corresponds to a profile of data contained in an external data base.

12. A method for locating an implant implanted into a human, said implant having a transponder (132) associated therewith characterised in that at least a portion of the human is externally scanned with a remote reader (34) to generate read signals whereby the strongest read signal generated by said remote reader determines the location of the implant.

13. A method as claimed in claim 12, wherein the transponder (132) is encoded with a unique tag so that said transponder may be readily identified.

14. A method as claimed in claim 12 or 13, wherein the transponder (132) is physically secured to said implant prior to implantation so that said implant and transponder are implanted in physical proximity to each other.

15. A method as claimed in claim 12 or 13, wherein the transponder is affixed to said implant prior to implantation.

16. A method for identifying an implant (130) adapted for temporary implantation in a human, said method comprising the steps of:
associating a transponder (132) with said implant;
encoding said transponder (132) with a unique tag so that said transponder may be readily identified; and contemporaneously implanting said implant (130) and said transponder (132) in a human.

17. The method of claim 16 wherein the step of associating includes the step of physically securing said transponder (132) to said implant (130) so that said implant and transponder are implanted in physical proximity with each other.

18. The method of claim 16 wherein the step of associating includes the step of affixing said transponder (132) to said implant (130).

19. A method for locating an implant (130) adapted for implantation in a human, said method comprising the steps of:
associating a transponder (132) with said implant;
encoding said transponder with a tag so that said tag may be read to locate said transponder; and implanting said implant and said transponder in a human.

20. The method of claim 19 wherein the step of associating includes the step of physically securing said transponder (132) to said implant (130) so that said implant and transponder are implanted in physical proximity with each other.

21. The method of claim 20, further comprising the steps of:
externally scanning at least a portion of said human with a remote reader (34) to generate read signals; and determining a location of said human that corresponds to a strongest read signal generated by said remote reader.