WO1988008286A1

WO1988008286A1 - Artificial hair filament and method for implanting same

Info

Publication number: WO1988008286A1
Application number: PCT/US1988/001362
Authority: WO
Inventors: Bernard A. Kirshbaum
Original assignee: Kirshbaum Bernard A
Priority date: 1987-04-28
Filing date: 1988-04-25
Publication date: 1988-11-03
Also published as: IL86204A0; AU1721188A

Abstract

An artificial hair filament (10) for implanting in living tissue as a replacement for natural hair includes a stem section consisting essentilly of expanded polytetrafluoroethylene having an open microstructure formed of nodes with interconnecting fibrils having a length of from about 50 to about 500 microns, and wherein the filaments (10) include at least one radially extending anchoring member (e.g. 34, 36, 44, 54, 56) adjacent a downstream end thereof. An apparatus (70) in accordance with this invention includes an outer needle and guide member (72) having a lower piercing end (74) for piercing tissue (e.g., 14) as part of a filament implantation procedure, and an inner, stepped driving member (76) movable relative to the needle and guide member (72) for engaging the anchoring member of the filament at different locations for forcing the filament out of the needle and guide member (72). A method of implanting the artificial filament (10) of this invention also forms a part of the present invention.

Description

ARTIFICIAL HAIR FILAMENT AND METHOD FOR IMPLANTING SAME

Field of the Invention This invention relates generally to artificial hair filaments for implantation into the scalp of balding indivi¬ duals, and more specifically to a unique artificial hair filament for that purpose, and to a method and apparatus for implanting the filament.

Background Art Hair implants are becoming increasingly more popular more and more balding individuals realize that such implants significantly enhance their appearance. However, attempts to implant synthetic fibers such as polyesters and polyacrylics, ■ often by non- edically trained personnel, have led to uniform unsuccessful results, leading to a ban on such implantation b the Food and Drug Administration under the Medical Device Amendments of 1976.

The prior art techniques for implanting artificial fibers employ the fibers singly or in groups or bunches of th to eight strands each. It is quite common for implantation o full scalp to require the use of up to as many as 1,800 indivi dual hair filaments; thus requiring on the order of 300 implan each with a grouping of approximately six strands. As stated above, the use of synthetic fibers in these transplants has generally been unsuccessful, very often producing serious infection, inflammation and other undesired tissue and foreign body reactions, with spontaneous rejection or sometimes requiring extirpation.

Some of the complications associated with the implan¬ tation of artificial fibers or filaments has been traced to th absence of a suitable interface between the synthetic implant and the scalp tissue. What occurs in the prior art techniques is that the scalp tissue in the epidermis and dermis layers fo a loose envelope of cellular and fibrous tissue around the implanted filament, with the space between the envelope and th shaft of the implant providing an open area for the accumulati of debris and bacterial growth, thus permitting infection and inflammation to occur. A number of hair implant structures are disclosed in the patent literature_r as is exemplified by U.S. Patent Nos. 3,119,398 (Bennett, et al. ) ; 3,596,292 (Erb) and, 3,003,155 (Mielzynski, et al. ) . The patent literature also discloses a number of methods and apparatus for implanting natural and/or synthetic fibers as part of a hair implant procedure, as is exemplified in U.S. Patent Nos. 1,059,631 (Popovics); 1,061,00 (Parsegan); 3,062,214 (Maxwell); 3,699,969 (Allen); 3,998,230 (Miller) and 4,004,592 (Ya ada).

U.S. Patent No. 4,321,914, issued to Begovac, et al. , while being unrelated to hair implant methods and devices, doe disclose a percutaneous implant for providing a port of entry internal body spaces, and states that chronic use of such devices can result in infection and/or encapsulation of the implant by the epidermis. To eliminate this problem Begovac, al. teach that the subcutaneous portion of the button of the implant be provided with an upper skirt 12 and a lower skirt 1 of a porous polytetrafluoroethylene (PTFE). The upper and low skirts are described as being biologically inert, thus eliminating chronic inflammatory or foreign body responses. This patent specifically teaches that the upper skirt portion should terminate below the outer surface of the skin so as to permit the epidermis 22 to migrate down the implant and grow into the upper skirt microstructure, rather than growing completely around the device. Begovac, et al. suggests that attempts to avoid infection were unsuccessful when the PTFE layer covered portions of the button which projected completel through the skin surface; thus teaching the undesirability of such a construction in percutaneous implants of the type employing a porous PTFE skirt.

U.S. Patent Nos. 3,953,566 and 4,187,390, both issued to Gore, disclose processes for forming expanded, amorphously locked porous materials made from polytetrafluoroethylene and products produced by such processes. These materials are described as consisting of a number of nodes interconnected by small fibrils. The nodes are specified to have an average micron size of about 55 and are fairly irregular in shape. These nodes are interconnected to each other by fibrils havin lengths which vary from about 5 to 500 microns, depending upo the amount of expansion employed to form the materials. These materials also are described as having an extremely high tensi strength, as compared to the materials identified by Gore as constituting prior art. Similar processes and products are disclosed in Gore U.S. Patent No. 3,962,153, with a specific disclosure of making highly expanded filaments being set forth in Example 18 of said patent.

U.S. Patent No. 4,482,516, issued Bowman et al. , and assigned to W.L. Gore & Associates, Inc., teaches the manufac¬ ture of porous articles of PTFE, which are coarser than the structures disclosed in the above discussed Gore '566 and '390 patents. The filaments described in the '516 patent are chara terized by relatively large nodes interconnected by relatively long fibrils, as compared to the prior art structures. Bowman et al. state that, in many instances, a coarser microstructure is desired, and in particular, in the biological field where t microstructure needs to be large enough to allow cellular ingrowth and incorporation of body tissue.

It is applicant's understanding that filaments of expanded polytetrafluoroethylene of the type disclosed in one more of the Gore '566, '153 and '390 patents or of the type disclosed in the Bowman et al. '516 patent, presently are bein used in an experimental or test environment for suture applica tions. These filaments have an outer diameter on the order of 0.18 millimeters.

To the best of applicant's knowledge, prior to the instant invention, there has been no teaching of utilizing expanded polytetrafluoroethylene filaments of the type disclos in either the Gore '566 patent or the Bowman et al. '516 paten in hair transplants. In fact, in the area of percutaneous implants, wherein a portion of the implant is intended to exte outwardly beyond the epidermal layer, the prior art, and in particular the earlier discussed Begovac, et al. patent No. 4,321,914, suggests that expanded PTFE material of the type disclosed in the Gore and Bowman et al. patents should termina within the epidermis to prevent infection and/or encapsulation of the implant.

Objects of the Invention

It is a general object of this invention to provide a improved synthetic or artificial hair filament and a method an apparatus for implanting same.

It is a more specific object of this invention to provide a synthetic or artificial hair filament which minimize the likelihood of infection and/or rejection by body tissue.

It is a further object of this. invention to provide a synthetic or artificial hair filament which cooperates with cellular structure in the epidermis and fibrous structure in t dermis to assist in positively anchoring the filament in the scalp. Optionally the^* filament may cooperate with inflammator cellular structure in the subcutaneous layer of the scalp to further assist in anchoring the filament in the scalp.

It is a further object of this invention to provide a synthetic or artificial hair filament and a method of implanti same which provides a durable, strong and permanent constructi

It is a further object of this invention to provide a apparatus for implanting artificial hair filaments into the scalp in an efficient and reliable manner.

Summary of the Invention

In accordance with this invention an artificial hair filament implanted in living tissue within the scalp as a replacement for natural hair includes expanded polytetra- fluoroethylene (PTFE) having an open microstructure formed by nodes interconnected by fibrils having a length in the range o from about 50 to about 500 microns. Preferably the diameter o the filament is on the order of 0.15-0.25 millimeters.

In accordance with the preferred construction the fil ment of this invention includes a lower anchoring section whic preferably extends at least partially into the subcutaneous tissue immediately below the dermis or coriu . The anchoring section can take on a wide variety of forms, including radia extending fingers, barbs, disks and the like.

In accordance with another aspect of this invention apparatus for implanting the artificial hair filament includ an outer, substantially elongate needle and guide member hav a hollow interior in which the filament to be implanted is retained, with the lower anchoring section of the filament flexed in an upstream direction, into engagement with inner surfaces of said needle and guide member. A stepped, hollow driving member is positioned within the needle and guide mem and receives the stem of the artifical hair filament to be implanted. The stepped driving member has an upper cylindric section which is dimensioned to be positioned closely adjacen the inner su'rface of the needle and guide member, and a lower cylindrical section of a smaller diameter than the upper cylindrical section. The upper and lower cylindrical section are interconnected to each other through a downwardly facing shoulder which is closely adjacent the inner surface of the needle and guide member to thereby engage the outer periphery the flexed anchoring section of the filament. The distal end the lower cylindrical section closely surrounds the axial sha of the filament for engaging the anchoring section substantia at the junction of said anchoring section with the axial stem After a lower piercing end of the needle and guide member has been inserted into the scalp to the level at which the filame is to be implanted, the driving member is moved in an axially downward direction to thereby apply a force to the anchoring section at both its radially outward end and at its junction with the axial stem to thereby drive the filament out of the needle and guide member for implantation into the scalp.

Brief Description of the Drawings Other objects and many of the attendant advantages o this invention will be readily appreciated as the same become better understood by reference to the following detailed desc tion when considered in connection with the accompanying drawings wherein: Fig. 1 is a fragmentary view on a reduced scale illus trating a plurality of artificial filaments in accordance with this invention, implanted in the scalp of a human being;

Fig. 2 is a greatly enlarged, fragmentary sectional view through the scalp of a human being, illustrating the icroporous structure of the artificial filament of this inven tion and a preferred orientation of the filament within the scalp;

Fig. 3 is an enlarged, fragmentary elevational view o the downstream end of an apparatus of this invention for inser ing artificial filaments of this invention into the scalp, wit parts of the apparatus broken away to show details of construction;

Fig. 4 is an enlarged, fragmentary elevational view showing an artificial filament of this invention implanted int the scalp, and with the apparatus illustrated in Fig. 3 partially withdrawn from the implanted filament;

Fig. 5 is an enlarged, fragmentary isometric view ill traitng a modified anchoring section of the filament of this invention employing barbs as the anchors;

Fig. 6 is a view similar to Fig. 5, but illustrating further modified anchoring section of the filament of this invention employing discs as anchors.

Detailed Description of the Preferred Embodiment _ Referring now in greater detail to the various figure of the drawings wherein like reference characters refer to lik parts, an artificial hair filament embodying the present invention is generally shown at 10 in Figs. 1 and 2.

As can be seen best in Fig. 1 a plurality of filament 10 in accordance with this invention are implanted in the skin 12 of a human scalp. The skin is made up of well known layers which are most clearly shown in schematic form in Fig. 2. In particular, the skin includes an outer epidermis 14 directly overlying the corium or dermis 16 which, in turn, merges into the subcutaneous tissue 18. The epidermis 14 includes an outermost layer known a the stratum corneum 19, which is composed of scale-like, keratinized cells which are continuously sloughed off from th skin surface. Underlying the stratum corneum (but separated an intermediate layer referred to as the stratum granulosum, which is not shown in the drawings) is the prickle layer 22 which consists predominantly of prickle cells 24. As will be explained hereinafter, the prickle cells cooperate with the h filaments of this invention to aid in positively securing the filaments within the scalp. The final, or innermost layer of the epidermis is the basal cell layer which contains the stem mother cells from which the other cells of the epidermis^" deri

The corium or dermis 16 is predominantly made up of fibrous structure, and predominantly collagen fibers 28, whic account for over 90% of the bulk of the corium. These collag fibers 28 are generally wavy, non-branching structures which also cooperate with the artificial filaments 10 of this inven tion to stabilize the filaments within the s^'calp.

The subcutaneous tissue 18 is a fatty layer formed predominantly of fatty cells. As will be explained in greate detail hereinafter, the fatty cells of the subcutaneous tissu also cooperate with the artificial filaments of this inventio in those embodiments of the invention wherein the filaments a implanted into the. subcutaneous tissue.

Referring specifically to Fig. 2 an artificial filam 10 in accordance with this invention is formed of expanded po tetrafluoroethylene (PTFR) made in accordance with either the teachings of the earlier mentioned Gore Patent No. 3,953,566, of the earlier-mentioned Bowman et al. Patent No. 4,482,516. However, the coarser filaments made in accordance with the tea ings in the "516 patent are preferred. The subject matter of both the '566 patent and '516 patent are herein incorporated b reference.

Suffice it to state that each of the filaments are of very small diameter, approximately the diameter of natural hai (e.g. , in the range of approximately 0.15-0.25 millimeters). The expanded filaments of this invention have a high matrix tensile strength (i.e., preferably above 7,000 p.s.i., as computed in accordance with the method described in the Gore '566 patent), and are characterized by an opened microstructur defined by a plurality of nodes interconnected by fibrils havi a length in the range from about 50 to about 500 microns. The openings or pores extending through the filaments 10 are illustrated at 30 in the various Figures.

Referring to Fig. 2 , the filaments 10 preferably include an anchoring section 32 at the lowermost end thereof. This anchoring section can be molded directly into the filamen as part of the formation process. In the illustrated embodime the anchoring section 32 is unitarily formed with the elongate filament stem. As can be seen best in Fig. 2 the anchoring section 32 includes axially spaced-apart, upper and lower sets of anchoring members 34 and 36, respectively. The set of anch ing members 34 includes circuraferentially spaced apart, radial extending locking or anchoring fingers 38 which are generally flexible. The lower set of anchoring members 36 includes an identical arrangement of circuraferentially spaced apart, radi¬ ally extending, flexible fingers 39. As is most clearly shown in Fig. 2 the raicroporous structure of the filament extends in and throughout the anchoring section 32.

Referring in Fig. 5 an alternate embodiment of an artificial filament in accordance with this invention is illus trated at 40. This embodiment is identical to the filament 10 except for the construction of the lower anchoring section 42. In the filament 40 the anchoring section 42 is provided by a plurality of circuraferentially spaced-apart and axially offset barbs 44. These barbs each include an inclined outer peripher surface 46 which tapers in a downstream direction (in the direction in which the filament is to be inserted into the scalp) to a postion wherein it is flush with the axially extending stem of the filament. Preferably these barbs are integrally molded as part of the filament ^"40, and include the same microporous structure as the axial stem of said filament. Referring to Fig. 6 a further embodiment of an artificial filament in accordance with this invention is show at 50. This embodiment is identical to the earlier described embodiments, except for the construction of the anchoring section 52. In particular, the anchoring section 52 of the artificial filament 50 includes axially spaced-apart anchorin members 54 and 56. Each of these anchoring members is identi cal, including a generally planar disk 56 disposed generally horizontally to the main stem of the filament and extending radially therefrom, and a plurality of circumferentially spaced-apart, radially extending ribs 60 integrally molded as part of each disk for the purpose of reenforcing each said di In all embodiments of this invention the anchoring s tions include flexible elements which, in use, extend radiall outward from the axial stem of the filament to assist in anch ing, the filaments to the scalp, and thereby assist in establi ing and maintaining a permanent hair implantation.

It should be noted that known implant techniques can employed to implant the artificial filaments (10, 40 and 50) this invention into the scalp of a human being. For example, method and device similar to that described in Miller U.S. Patent No. 3,998,230 can be employed for this purpose. The Miller '230 patent is herein incorporated by reference. The present invention also relates to a unique apparatus 70 employed to insert a filament of this invention into the scalp of the human being. As can be seen in Fig. 3 apparatus 70 includes an outer, generally cylindrical needle guide member 72 having a sharp, piercing end 74 at the lower thereof. The piercing end is adapted to penetrate the epider 14, the corium 16, and, if desired, the subcutaneous tissue 18 so as. to position the lower anchoring section of a filament in the desired region of the scalp.

As can be seen ^'best in Fig. 3 the needle and guide member 72 has a hollow interior for receiving an inner, steppe driving member 76 and a filament (e.g., 10) which is to be implanted into the scalp. The stepped driving member has an upper cylindrical section 78 which is dimensioned to be positioned closely adjacent the inner surface 80 of the needle and guide member 72, and a lower cylinder section 82 of a smaller diameter than the upper cylindrical section. The uppe and lower cylindrical sections are interconnected through a downwardly facing shoulder 83 which is adapted to engage portions of the anchoring section 38 adjacent to the inner surface 80 of the needle and guide member 72. The lower cylindrical section 82 terminates in a distal end 85 which is adapted to engage the anchoring section 38 at its junction wit the stem of the filament.

As shown in Fig. 3 the anchoring fingers 38, 39 are flexed in an upstream direction, relative to the direction in which the filament is inserted into the scalp, with peripheral surfaces of the fingers 38 and 39 in engagement with the inner surface 80 of the outer needle and guide member 72. The downwardly facing shoulder 83 at the junction between- the uppe cylindrical^* section 78 and lower cylindrical section 82 of the driving member 76 engages the outer marginal ends of the flexe fingers 38 of the anchoring section 32. The distal end 85 of the lower cylindrical section 82 of the driving member 76 is dimensioned to closely surround the axial stem of the filament 10, engaging the fingers 38 (or any other members forming the anchoring section) adjacent the junction between the fingers 3 and the axial stem of the filament.

The manner in which the apparatus 70 is employed to insert the filament will now be described in connection with t filament 10 of this invention. However, it should be understo that the apparatus 70 will operate in a similar manner in conn tion with inserting the other filaments in accordance with thi invention.

In operation the filament 10 first is inserted into t driving member 76, until the distal end 85 of the lower cylind cal section 82 engages the fingers 38, at the junction of said fingers with the axial stem of the filament. The driving memb 76, with the filament therein, is then inserted into the needl and guide member 72. At this time the radially extending fingers 38 and 39 will be flexed in an upstream direction, relative to the direction in which the filament is inserted i the scalp, with the peripheral surfaces of the fingers 38 and in engagement with the inner surface 80 of the outer needle a guide member 72. When the fingers are so flexed, the downwar facing shoulder 83 of the driving member 76 is in position to engage the outer marginal ends of the fingers 38, in the regi adjacent the inner surface 80 of the needle and guide members 72, as is shown in Fig. 3.

After the filament to be implanted is inserted into t apparatus 70, the lower piercing end 74 of the needle and guid member 72 is forced into the scalp, through the epidermis 14 a dermis 16, and, if desired, partially into the subcutaneous tissue layer 18. Thereafter the inner driving member 76 is moved relative to the .outer needle and guide member 72 in an axial .downstream direction. This forces the filament 10 in a downstream direction until at least a portion of the anchoring section 32 clears the lower periphery of the needle and guide member 72, to permit the anchoring fingers 39 (and possibly fingers 38) to move radially outwardly and thereby aid in locking the filament within the scalp. Thereafter the outer needle and guide member 72 and inner driving member 76 are removed as a single unit from the scalp, as is illustrated in Fig. 4.

It should be noted that in accordance with this invention the prickle cells 24 in the prickle layer 22, as wel as the fibers 28 in the dermis 16 penetrate through and grow into the pores 30 of the filament. This provides a strong anchor for the filaments of this invention, and a tight interface^, between the tissue and filaments so as to preclude t accumulation of debris and bacterial growth, which can lead to infection and inflammation.

As is shown in Fig. 2 the radially extending fingers of the anchoring section 32 are disposed partially in the derm 16 and partially in the subcutaneous tissue 18, whereas the radially extending fingers 39 are disposed completely in the subcutaneous tissue. The portion of the subcutaneous tissue surrounding the fingers 39 has been omitted to more clearly sh the structural configuration of the lower set of anchoring members 36. If desired, the entire anchoring section 32 can b disposed in either the dermis 16 or subcutaneous tissue 18, or alternatively, as illustrated in Fig. 4, the upper set of anchoring members 34 can be disposed completely within the dermis 16, and the lower set of anchoring members 36 can be disposed completely with the subcutaneous tissue 18.

When the filament is to be implanted into the subcutaneous tissue 18, the subcutaneous tissue experiences an "insult" from the penetration of the apparatus 70 therein. Th evokes an inflammatory cellular response, thereby causing the inflammatory cells of the subcutaneous tissue to move to the site- of the antagonism (i.e., the site of filament implantatio to thereby encounter and grow into the pores 30 of the filamen

Without further elaboration, the foregoing will so fully illustrate my invention that others may, by applying current or future knowledge, adopt the same for use under various conditions of service.

Claims

What is claimed as the invention is:

1. An artificial hair filament having a central, axially extending stem with an anchoring section at the lower end thereof, characterized in that said stem consisting essentially of expanded polytetra luoroethylene having an ope microstructure formed of a plurality of nodes interconnected fibrils having a length of from about 50 to about 500 microns

2. The artificial hair filament of Claim 1 characterized in that the anchoring section includes at least one member which extends radially outwardly from the axially extending stem.

3. The artifical hair filament of Claim 1 characterize'd in that said anchoring section includes at leas one set of circuraferentially spaced-apart flexible fingers extending radially from the stem.

4. The artificial hair filament of Claim 3 characterized in that at least two sets of said circumferenti ally spaced-apart flexible fingers extend radially from the stem, said sets being axially spaced-apart from each other.

5. The artificial hair filament of Claim 2 characterized in that said anchoring section includes circumferentially and axially spaced-apart barbs which taper radially inwardly toward said stem in a downstream direction the filament.

6. The artificial hair filament of Claim 2 characterized in that said anchoring section includes at leas one radially extending disk.

7. The artificial hair filament of Claim 6 characterized in that said anchoring section includes at least two radially extending disks which are axially spaced-apart fr each other adjacent a downstream end of said filament.

8. In the method of implanting artificial filaments i living tissue as a replacement for natural hair, characterized by the steps of implanting artificial hair filaments having an axially extending stem consisting essentially of expanded polytetrafluoroethylene having an open microstructure formed of a plurality of nodes interconnected by fibrils having a length of from about 50 to about 500 microns.

9. The method of Claim 8 wherein the artificial hair filaments include radially extending anchoring means adjacent the downstream end thereof, characterized by the step of implanting the artificial hair filaments with said anchoring means extending at least partially into subcutaneous tissue below the dermis, and wherein the microstructure provides pores through which cells in the prickle layer of the epidermis and fibers in the derrais can infiltrate.

10. An apparatus for use in implanting artifical filaments in living tissue as a replacement for natural hair,

• characterized in that said apparatus comprises an outer needle and guide member having a hollow interior for receiving a driving member therein; a stepped driving member having an uppe cylindrical section positioned closely adjacent an inner surfac of the needle and guide member, and a lower cylindrical section of a smaller diameter than said upper cylindrical section and terminating in a lower distal end, said upper cylindrical section and lower cylindrical section being interconnected through a downwardly facing shoulder, said driving member havin an axial passage for closely surrounding an axial stem of the artificial filament to be implanted, said distal end and downwardly facing shoulder of the stepped driving member being adapted to engage different regions of a radially extending anchoring section of the filament to force said filament out of the needle and guide member.

11. The apparatus of claim 10 characterized in that the needle and guide member includes a lower piercing end adapted to penetrate the portion of the living tissue into whi the filament is to be implanted.

12. The apparatus of claim 10 charcterized in that radial dimension of the anchoring member of the filament, whe unconfined, is greater than the radius of the needle and guid member, whereby the radially extending anchoring section is flexed in an upstream direction against the inner surface of said needle and guide member prior to the filaments being for out of the needle and guide member.