CA2103024A1

CA2103024A1 - Thyroplasty implant

Info

Publication number: CA2103024A1
Application number: CA002103024A
Authority: CA
Inventors: William W. Montgomery; Stuart K. Montgomery
Original assignee: Individual
Current assignee: Boston Medical Products Inc
Priority date: 1991-05-30
Filing date: 1992-05-08
Publication date: 1992-12-01
Also published as: JPH06511159A; US5358522A; AU1904792A; US5344453A; EP0586503B1; JP3252373B2; EP0586503A4; DE69220944D1; ES2104924T3; US5326375A; EP0586503A1; DE69220944T2; WO1992021303A1

Abstract

A thyroplasty implant (10) having a tiered base (12) for anchoring in a window cut through a thyroid lamina and a projecting member (14) for causing medial displacement of a vocal cord. The tiered base has a bottom tier (16), a middle tier (18), and an upper tier (20), the bottom tier and upper tier being larger in area than the middle tier so as to facilitate anchoring the base in the window. The base is made of a firm biocompatible material to facilitate firm anchoring of the implant, and the projecting member being made of softer, biocompatible material that is sufficiently soft to avoid damage to the vocal cord. The projecting member (14) is generally triangular in shape and has a portion (26) that extends in a posterior direction from the base. A measuring tool (44) having a projecting member (46) of similar shape to that of the implant and movable stop member (60) is used to measure the optimum size implant.

Description

WO~2/21303 2 ~ ~ 3 ~ 2 ~ PCI/US~2/03937 q~HYROPI~STY IMP~NT
ield of the Im~ention The invention relates to a thyroplas~y implan~
5 which is anc:hored in a window aut throuqh a thyroid lamina and cause~; medial di~;placement of a vocal cord.

B~ckqround of the Inventic)n When ~ patient ' s vocal cord has b~en par21lyzed or is okherwise impaired, treatment can include medially ~ ~ 10 displac:ing the nonfuns::tioning vocal cord to reduce the ;' distance be~ween it and the other t functimling vocal cord to improve ~roice and preYent a~ iration. ~; is discussed n Is~;hi~i, Nobuhiko, Phc nosuraery, (5pring~r-Verla~, .Y., l98g), pp. 77-104 , the most co~on surgical .~` 15 technique to ~chieve this ~edial displacement is ~he c:ordal injec :~on of ~e~lon. ~ :~nother ltechni~ described in~ s ~refQrenae:~is~ cutting a: window ~in ~e thyroid lamisna and~medially; displacing~ the ¢ut:w~ndow material r~ erred to therein as the ~Iwindow~ ) by implanting a shi~or~a:plug~in:;the r~sulting window ~r~iEerred l~o h~ein-t~ a~:the`openingicut th~o~gh~th~ thyroid lamina~:7::the:plug~r:~shim having a projecting portion : that~:~extends in~ard~beyond th~ wind~w to di~place the cut ;: window ~aterial~,~and ~hus:~he paralyæed vocal cord on the 25: other:side~, toward~the functioning Yocal cord. One of : the~pluys d~scribe~in Ii~shiki ha~ a ! an ~nglea projecti~
portion~of ~rying height and a flange that i~ larger han the cut~window:and:r~sts on t~e outside surface of ; the lamina. Another~plug descri~ed in Isshiki has a : 30 proje ing portion:that has a pos~erior w~idge extension : that extends posteriorly beyond the windDw.
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Summar of the Invention In one aspect, the invention features, in general, a thyroplasty implant having a tiered ba~e with bottom and upper tiers that are larger in area than a wi~dow cut in the thyroid lamina and a middle ~ier that Ifi~s in the thyroid lamina. ~ projecting mem~er ext~nd~ng ~rom the upper tier causes medial displacement of a vocal cord.
: The triple-tiered approach ~acilitates firm anchoring of the implant at the desired location and orientation in the thyroid lamina.
In preferred embodiments the bottom tier extends beyond the middle tier around all sides, and the upper tier extends beyond the middle tier at only the antPrior and posterior sides. The middle tier is about between 5 mm nd 7 ~m wide and about between 10 mm and 12 ~m long.
: The projecting member has an inward dimension from the ~;1 base to the innermost surface of about ~etween 6 mm to ~: In another a~pect, the invention feature~, in general, a two-piece thyrvpla~ty implant haYing a base : made o~ a firm biocompatible material ~e.g., Shore A
d~rometer between:50 and 90, ~ost preferably about 703 to ~, ~ facilitate fi ~:anchoring of the implant and a projecting `~ ; member khat i~:~adapted to directly contact the vocal cord of softer, bioco~patible material (e.g.~, Shore A
J~ durome~er between 30 and 70, most preferably about 30, and in any event at least ten 1sss than the projecting ~emb~r) ~hat is sufficiently soft to avoid damage to the ~ vocal cord.
ri~ 30 In another a~pect, the invention features, in ; general, a thyr~plasty implant having a projecting member : that has tw~ generally parallel side walls that extend inward ~r~m two sides of a cut window and are generally riangula~ in shape. The triangle has a fir~t, base side :35 that extends along a base of the implant and extends .~, ''2 :, . ' I
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WO 92/21~03 2 1 ~ 3 ~ 2 ~ Pcr/usg2/o3g37 generally parallel to the thyroid lamina when implanted, a ~;econd, rear ~;ide that extends posteriorly (when implanted) from the base side and makes an oblique angle with the base side, and a third, inner side that make~
S acute angles with the ba~;e side and the rear side. . The inn~rmo~;t sur~ace of the projecting member ~etween the inner sides c: f the triangles s:~f the two side walls) is arcuake at its junctions with ~he ~;ide wall~; and with the rear ~;urface between the rear sides of the triangle. The 10 shape of the triangle permits medial displac~metlt at a preferred location on the vocal cord (making desired contact with the vocal proce~;s of the arytenoid) at the æame time as anchoring the base in a pref erred location f or cutting a window in the thyroid lamina, the latter 15 location beinçl offset from the former (preferably by about between 2 mm to 3 mm from the posterior side of the : ~ window to the posterior ;ide of the projecting member).
~h,e arcuate surfaces are designed to ~acilitate desired ~; direct cont~ct and reduce potential tr~uma to the vocal 2 0 cord . : :
In ano~her aspect the invention f ~a~ure~
determining ~he optimum i~nplant: - ize by: u~i~g a measuring ~: : tool havin~ a~ proj~cting ~ember o~E similar shape to that ~: of the implant and a~ movable stop member that rests out~;ide of the ~window~. ~he stop member pre~erably i~ an ela~to~@ric ring ;~ha is engaged betw~Qn ridges on a calibrated portion of the tool.
' :: Other ~advantages and faatures of the invention will be ~apparent from the following description of a '''.! 30 pre~erred embodiment thereof and from the claims.

DescriDtion of the Pref erred 13mbodiment he pref erred embodiment will n~w be described .
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3 PCr/USs2/03937 ~3~7~4 Drawinqs Fig " 1 is an eleva ~ ion of a thyroplasty implant ~: , according to the invention.
Fig. 2 i~; a side view of the FigO 1 ~hyroplasty 5 implant. , ~ --;, Fig~;. 3 and 4 are ~;ide and end eleva1~ions of a .
tool us~d to determine what size implant should be us~d.
Fig. 5 is a diagrammati ::, horizontal ~;ectional :: view howing the Fig. 1 ~hyroplasty implant mounted in a 10 window cut through a patient ' thyroid lamina and .~ medially displac:ing a vscal cord.

;, Structure ,, . ~
Referring to Figs. 1 and 2, thyroplasty i~plant 10 has tiered base 12 and triangular projes:ting member 14.
; 15 I~plant 10 is made in four ~or more) fe~aIe sizes and in four ~or more) male izes. The female siz~s have one ;ize base 12, ~ and the male ~izes ha~e a different size ba~;e 12, irl order to accommodate the differen~ #iZeS of fema~e and male larynges. Within he female and male size~, the~riangular projecting members 14 have different height6, permitting the surgeon to select the heigh~ ~hat will give ~the best results.
Base 12~ s bottom tier 16 (1 mm ~hial~, middle tier: ~18 (2 mm~- thick for; femal~ E;iZ2S and 3 mm thick for male ~size~;), and:upper tier 20 (l ~n ~ick). In the femal~ imp~ant~,: bottom tier 16 i~; ;12 mm long ahd 7 wid@, middle tier- 18 is 10 mm long and 5 mm wide, and ~- ~ upper tier 20 is l~ mm long ind 5 mm wide. In the male !
:implants p bottom tier 16 is 14 mIa long and 9 mm wide, : 30 middle tier 18 is 12 mm long and 7 mm wide, and upper tier 20 is 14 mm long and 7 mm wide.
Projecting member 14 has the Bame width and length ?.`` ~ at its bottom as the l~pper tier 20 below it. Projectirag member 14 has two generally parallel side surfaces 22 1 .
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W092/2~303 2 1 ~ 3 0 2 4 PCT/US92/03937 that are generally triangular in shape. The triangle has a first, base ~ide 24 that extends along upper tier 20 of base 1~ of the imp~ant, a second, rear side 26 that extends posteriorly (when implanted) from base side 24 and makes an oblique angle ~ with base side 2A, and a--third, upper side 28 that ~akes ~cute angle ~ with the ba e side 24 and acute angle 7 with rear ~ide 26. Side wall~ 22 curve toward each sther at upper ~ide 28 at a radius that is equal to one-half of its width, so that the uppermost surface of projecting member 14 is arcuate..
The junction 30 between the second and third sides 26, 28 on all sizes has a radius o~ curvature Rl of 1,59 mm, and the junction 3~ between the fir~t and third sides 24, 28 on all sizes has a radius of curvature R2 of 1.4 mm.
~xis 34 along first side 24 intersects axis 36 along ! third side 2~ at a point 38 that is 2.5 mm beyond upper tier 20 in th~ female sizes and 3.5 mm beyond upper tier 20 in the male sîzes. ~he rearmost por~ion 40 of projecting member 14 is 2 mm behind upper tier 20 in the female sizes and 3 mm behind upper ti~r 20 in the male sizes; *his offset permits contact with the vocal process of the arytenoid at the same time as anchoring the base ..
`. in a preferred location for eutting a window in the thyroid lami~a. The arcuate surfaces are designed to ~: 25 facilitate de~ired direct contact and reduce potential trauma to the vocal cord. The heights H of the uppermost por~ions 42 of projecting member 14 above upper tier 20 are 6 mm, 7 m~, 8 mm and 9 mm for the f~male sizes, and 8 mm, 9 mm, 10 mm and 11 mm~for the m~le sizes.
Implan~ 10 is made of bioco~patible materials, in particular two medical gra~e silicone or thermoplastic elastomer polymers of dif~erent durometer (available from Dow Corning Midland, Michigan under the Silastic trade ` : desi~nation and Concept Polymers t Clearwater, Florida, under the C-Flex ~rade designation, respectively). Base , .

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W~ 92/21303 ~ P~/USg2/03937 ':

12 is made of high durometer (approximately 70 durometer Shore A) material in order to be suf f iciently f irm to provide secure anchoring in thl3 thyroid lami~a.
Prs~jecting member 14 is made o~ low durometer material (approximately 30 durc~meter Shore ~) in order,to be -suf f ic:iently soft to avoid damage to the voca~l cord.
I~plant 10 is ~nade by insert ~o~ ding, f ir~t molding one piece, and then placing it in the mold f or the other piece .
Referring to Fig~. 3 and 4, there is shown tool 44 for use in determining which size implant should be used.
Going frGm top to bottom, tool 44 has triangu~ar projecting member 46, extension d.8, calibrated att~chment portion 50, shaft 52, b~ase 54, and knurled handle 56.
Two ~;izes are provided for tool 40, one size for use with women, and another size for use with men. Extension 48 has ~ rectangular cross-~;ection the same . ize as middle tier 18 of implant lOo Triangular projecting member 40 ~, iæ of the sam~ material as and i5 gen rally C3~ the ame : '!
: 20 ~;hape as projecting memb r 14 of implant 10. Calibrated ~: portion 50 has ridges~ 58 spaced 1 m~n, apart (center to ~r center) ad~pted to receive resilient ring 60 at different location~; corresponding to different heights ~ ~or ~Z~ implant 10. In,dicia 62 ~etween adjace~t ridges 58 : ~ :
irldicate ~he height H for implant 10 that :Eunction imi3 arly to tool 40 when ring 60 is in, the indicat~d ~ ~ ~ position.

'~`' ! Use The surgical procedure for imp~anting thyroplasty 30 implant 10 is performed under local anesthesia. P,fter surgical exposure of the larynx, window 64 is created in th~roid lamina 66 by cutting a rectangular ~ection of cartilage using either a surgical blade or ~urgical saw.
., The dimensions of window 64 are 5 mm ~y 10 mm for females ~ ..
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WO92/21303 21~ 3 0 2 ~ PCT/US92~03937 and 7 mm by 12 mm for males. The anterior edge of window 64 is located a di~ ance laterally from the anterior midline of the thyroid cartilage of S mm in th~ female and of 7 mm in the male. The perichondrium is elevated unde~neath the cartilage window, and the cut portiQn of cartilage is carefully removed from the win~ow. Th~
perichondri~m is el~vated in all direction~ underneath the windowO An anterior anteroposterior line of cautery is m~de in the perichondrium along the length of the mid portion of the window. An incision of the perichondrium is carefully accomplished wi~hout touching the underlying muscle fibers.
Tool 44 is then used to determine which size impl~nt 10 should be selected, with ring 60 initially in the position corresponding to the shortest height implant. Triangular projecting me~ber 46 i5 intrcduced through window~64 until ring 60 r~sts against outer ,~ surface 6~ of ~he thyroid lamina. The patient is asked `'f to p~onate to~see i~ ~hare is a good improv~ment in his ; ~ ~ 20 or ~Qr voice, and a fiberoptic laryngoscope is inserted ~; i~t~ tha area above the larynx to ~2e if the vocal cord ~,~ has been medialized:to a point where the vocal cords touch during phonation. If the optimum voice has not t; ~ been achie~ed, and the vocal cord~ need to ~e moved more medially, tool 44 ~s:~emoved, and ring 60 is moved to the ,i .
ne~t groo~e position on calibrated portion 50. `
~,fl ' Triangular projecting meimber 46 is introduced through-~: window 64 and the voice is analyzed and the cords ~- examin~d, and so on until the optimum size i~plant has : 30 been determined.
The physician then salects the optimum size implant 10~ Obtuse triangular projecting member 14 of ~; impl~.nt 10 is first introduced through the window in the thyroid lamina, the overhanging portion at the ~unction i~ 35 of ~ides 26, 28 being posterior. Upper tier 20 of base c.~;., W092~2~303 3~ P~T/US9~/03~37 12 i~ also inserted in the window, using a curved instrument inserted between the top and bottom tiers of the base of the implant, and implan~ 10 snaps into place.
Upper tier 20 becomes an internal flange that helps prev2nt displacement of i~plant 10. Middle ~ier 18 of base 12 remains in thyroid lamina window 64. Bottom ti~r 16 of base 12 acts as an ext~rnal flange to help prevent i~plant 10 from mo~ing through thyroid lamina window.
The perichondrium is ~utured over the implant to further enhance its ~tability, and the incision is repaired.
Once the implant has been inserted, the chance of medial and lateral displacement is remote, as is migration o~
the implant. I~ the implant requires changing either at the time of surgery o~ durinq a secondary procedure, the posterior end of the implant is grasped with forceps or a mosquito he~ost~t. With outward pressure, the implant snap~ out easily without damaging ~ither cartilaginou~ or s~ft kissue structur~s. Because of uniformity o~ base .~ design, different size implants can be reinserted with no change in th~ thyroid cartilage window.
., ;' Impl~nt 10 has a~plic~tion for treatment for unila~ral vocal cord paralysis, after a h~milaryngectomy, following laryngeal trauma when vocal : cords do not approximate, for tr~atment of bowed vocal ~, 25 cord~, and for treatme~t of vocal cord atrophy. The u~e '~ of a plurality of izes and measuring instrument 44 `~ guarantees that the optimum size is employed ~or the p~tient, It also avoids~the need to fashion or alter the implant at time of ~urgery. ~ !
i~: 30 Other embodiments of the invention are within the cope of the appended claims.
j ~ What is claimed is:
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Claims

1. A thyroplasty implant for anchoring in a window cut through a thyroid lamina and causing medial displacement of a vocal cord comprising a tiered base having a bottom tier, a middle tier, and an upper tier, said bottom tier and said upper tier being larger in area than said middle tier so as to facilitate anchoring of said base in a said window that is shaped to receive said middle tier therein and has an area that is less than the areas of said bottom and upper tiers, and a projecting member extending from said upper tier for causing medial displacement of a vocal cord, said base and said projecting member being made of biocompatible material.

2. A thyroplasty implant for anchoring in a window cut through a thyroid lamina and causing medial displacement of a vocal cord comprising a base for anchoring in a said window, and a projecting member extending from said base for causing medial displacement of a vocal cord, said base being made of a firm biocompatible material to facilitate firm anchoring of the implant, said projecting member being made of softer, biocompatible material that is sufficiently soft to avoid damage to the vocal cord.

3. A thyroplasty implant for-anchoring in a window cut through a thyroid lamina and causing medial displacement of a vocal cord comprising a base for anchoring in a said window, and a projecting member extending from said base for causing medial displacement of a vocal cord, said projecting member having two generally parallel side walls that extend inward from two sides of said window and are generally triangular in shape, the triangle having a first, base side that extends along a base of the implant, a second, rear side that makes an oblique angle with the base side, and a third, inner side that makes acute angles with the base side and the rear side, the innermost surface of said projecting member between the inner ides of said triangles of the two side walls being arcuate at its junctions with the side walls and with the rear surface between the rear sides of said triangle, said base and said projecting member being made of biocompatible material.

4. The implant of claim 1 wherein said base is made of a firm biocompatible material to facilitate firm anchoring of the implant, and said projecting member is made of softer, biocompatible material that is sufficiently soft to avoid damage to the vocal cord.

5. The implant of claim 4 wherein said projecting member has two generally parallel side walls that extend inward from two sides of said window and are generally triangular in shape, the triangle having a first, base side that extends along said base of the implant, a second, rear side that makes an oblique angle with the base side, and a third, inner side that makes acute angles with the base side and the rear side, the innermost surface of said projecting member between the inner sides of said triangles of the two side walls being arcuate at its junctions with the side walls and with the rear surface between the rear sides of said triangle.

6. The implant of claim 3 wherein said base is made of a firm biocompatible material to facilitate firm anchoring of the implant, and said projecting member is made of softer, biocompatible material that is sufficiently soft to avoid damage to the vocal cord.

7. The implant of claim 2 wherein said base is made of material having a Shore A durometer between 50 and 90, and said projecting member is made of material having a Shore A durometer between 30 and 70, and the base material durometer is at least ten greater than the projecting member durometer.

8 . The implant of claim 7 wherein said projecting member durometer is between 30 and 50:, and the base durometer is between 50 and 90.
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9. The implant of claim 8 wherein said projecting member durometer is between 30 and 40, and the base durometer is between 60 and 80.

10. The implant of claim 1 wherein said bottom tier extend outward beyond said middle tier all of the way around said middle tier.

11. The implant of claim 10 wherein said upper tier extends outward beyond said middle tier on two ends of said base.

12. The implant of claim 1 wherein said middle tier is about between 5 mm and 7 mm wide and about between 10 mm and 12 mm long.

13. The implant of claim 11 wherein said middle tier is about between 5 mm and 7 mm wide and about between 10 mm and 12 mm long.

14 . The implant of claim 3 wherein said projecting member has an inward dimension from said base to said innermost surface of about between 6 mm and 10 mm.

15. The implant of claim 14 wherein said rear side extends about between 2 mm and 3 mm beyond said base.

16. A method of implanting a thyroplasty implant used to cause medial displacement of a vocal cord comprising cutting the border of a window in a thyroid lamina, removing the material within said border to create said window through said thyroid lamina, and anchoring the base of an implant in said window, said implant having a projecting member contacting and causing medial displacement of said vocal cord.

17. The method of claim 15 wherein said base of said implant is a tiered base having a bottom tier, a middle tier, and an upper tier, said bottom tier and said upper tier being larger in area than said middle tier so as to facilitate anchoring said base in a said window that is shaped to receive said middle tier therein and has an area that is less than the areas of said bottom and upper tiers.

18. The method of claim 17 wherein said base is made of a firm biocompatible material to facilitate firm anchoring of the implant, said projecting member being made of softer, biocompatible material that is sufficiently soft to avoid damage to the vocal cord.

19. The method of claim 18 wherein said projecting member has two generally parallel side walls that extend inward from two sides of said window and are generally triangular in shape, the triangle having a first, base side that extends along said base of the implant, a second, rear side that makes an oblique angle with the base side, and a third, inner side that makes acute angles with the base side and the rear side, the innermost surface of said projecting member between the inner sides of said triangles of the two side walls being arcuate at its junctions with the side walls and with the rear surface between the rear sides of said triangle.

20. A method of implanting a thyroplasty implant used to cause medial displacement of a vocal cord comprising cutting the border of a window in a thyroid lamina, removing the material within said border to create said window through said thyroid lamina, manually displacing said vocal cord through said.
window and observing phonation to determine the desired displacement providing the desired affect on phonation, and implanting an implant that is sized to have the same displacement as said desired displacement.

21. The method of claim 20 wherein said manually displacing and said observing include providing a tool having a projecting member having a shape similar to the shape of a projecting member of said implant and a movable stop member that is larger than and rests against the outside surface of the thyroid lamina around said window at one of a plurality of calibrated positions on said tool, said calibrated position being at different distances with respect to the end of said projecting member of said tool and corresponding to different sizes of implants, and introducing said projecting member through said window and evaluating phonation with said stop member at different positions to determine the best size of implant.

22. A tool for determining the height of a thyroplasty implant to be implanted, said implant having a flanged base adapted to sit outside of a window through the thyroid lamina and a projecting member adapted to medially displace a vocal cord, said tool comprising a projecting member having a shape that is similar to the shape of said projecting member of said implant, and a movable top member that is larger than said window and rests against the outside surface of the thyroid lamina around said window at one of a plurality of calibrated positions on said tool, said calibrated positions being at different distances with respect to the end of said projecting member of said tool and corresponding to different sizes of implants.

23. The tool of claim 22 wherein said movable stop member is an elastomeric ring.

24. The tool of claim 23 wherein said calibrated positions are separated by ridges.