Patent Publication Number: US-2004049206-A1

Title: Scalp tensioner

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to harvesting of hair grafts in preparation for hair transplantation, and in particular relates to a scalp tensioner which tensions the scalp at the harvest site so as to facilitate harvesting of the hair grafts.  
       [0003] 2. Description of the Related Art  
       [0004] With increasingly better surgical techniques and refined procedures, hair transplantation has become an increasingly popular treatment for male pattern baldness. According to this technique, hair grafts from a donor site are usually taken in a fully-haired region at the lower scalp of the patient and then are harvested and the hair grafts are transplanted to a recipient site.  
       [0005] Although many harvesting techniques have been used, one older, popular technique uses a simple punch-harvest of the hair graft. According to this technique, the donor site is prepared by close cutting of the hair, leaving only a hair stub which serves as a marker to the surgeon so as to locate potential grafts. Then, a generally circular punch (rotating or non-rotating) is positioned over a desired harvest site, as shown in FIG. 1A, which in cross-section shows punch  10  positioned over harvest site  111  in scalp  12  over skull  14 . The surgeon then presses punch  10  through scalp  12  until the proper depth is obtained, whereafter the punch and the harvested hair graft are withdrawn.  
       [0006] This punch-harvesting technique was initially developed at a time when hair grafts were formed of plugs of a large number of hairs, such as 20 to 30 hairs each. More recent hair transplantation techniques have achieved more realistic and natural results through the use of very small grafts, where each plug contains only a few hairs. To accomplish this, if the diameter of the punch has decreased, it leads to difficulties in the punch-harvest technique.  
       [0007]FIG. 1B illustrates one such difficulty. As seen there, as the punch  10  is depressed onto the scalp, scalp  12  deforms causing the target graft  15  to deflect in a more-or-less unpredictable way. Then, as the surgeon continues to depress punch  10 , the punch  10  often will amputate the lower end  15   a  of the graft as illustrated by dotted line  16 . Such a graft may be non-viable and may fail after transplantation.  
       [0008] This result is well-understood by skilled hair transplantation surgeons. To harden the scalp, such surgeons generally utilize tumescence, rock-hard tumescence or apply lateral hand pressure to the scalp. Tumescence is a technique whereby fluid is injected directly into tissue, skin, and the area below the skin, to such a degree that the injection area swells as a result of the volume of fluid injected. The amount of swelling is directly proportional to the amount of fluid injected, however, within seconds of the injection, much of the fluid diffuses out of the local area. Rock-hard tumescence occurs when an area is rapidly injected with a large volume of fluid. These skilled surgeons understand that a hardened scalp provides less latitude for the scalp to deform during punch-harvesting, with consequent reduction in the deformation of the skin when the grafts are taken. However, because tumescence, as well as rock-hard tumescence, is temporary, lasting only seconds, good hair graft harvesting is highly dependent on a small window of time. Therefore, recurring tumescence is required, making this approach unacceptable for any significant number of grafts.  
       SUMMARY OF THE INVENTION  
       [0009] It is an object of the invention to provide a scalp tensioner which provides automatic tensioning of the scalp in the area of a donor site so as to facilitate harvesting of hair grafts, preferably with a higher proportion of viable grafts as compared to tumescence or manual tensioning.  
       [0010] According to one aspect, a scalp tensioner according to the invention includes two or more generally opposed support structures which are arranged to form an open space therebetween, with each support structure having a gripping mechanism for gripping the scalp. A biasing mechanism biases the support structures outwardly away from each other, yet also permits movement of the support structures toward each other for placement on the scalp.  
       [0011] In use, the support structures and their corresponding gripping mechanisms are moved toward each other against bias by the biasing mechanism. The gripping mechanisms are engaged with the scalp, and the biasing mechanism is activated so as to tension the scalp, whereby the open space between the support structures permits harvesting of hair grafts from the tensioned scalp.  
       [0012] Preferably, the support structures are slidingly engaged on guide rods, and the biasing mechanism is comprised of a coil spring coaxially mounted around the rods. Such a structure permits the surgeon to grip the support structures and move them toward each other against the coil spring, and thereafter engage the gripping mechanism with the scalp and permit the coil springs to expand and tension the scalp.  
       [0013] Good results are also obtainable when the biasing mechanism is a geared, ratchet, screw or head brace mechanism.  
       [0014] In particularly preferred embodiments, the gripping mechanism is a linear or planar array of needles, teeth, or other pointed structures that pierce the epidermis of the scalp so as to grip it. Effective results are also obtained when the gripping structure is hair clamp which clamps uncut hair in the vicinity of the donor site.  
       [0015] This brief summary has been provided so that the nature of the invention may be understood quickly. A more complete understanding of the invention can be obtained by reference to the following detailed description of the preferred embodiment thereof in connection with the attached drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0016]FIGS. 1A and 1B are views showing a conventional punch-harvesting procedure for hair grafts.  
     [0017]FIG. 2 is a perspective view showing a scalp tensioner according to a preferred embodiment of the invention.  
     [0018]FIG. 3 is a cross-sectional view illustrating harvesting of hair grafts using a scalp tensioner according to the invention.  
     [0019]FIG. 4 is a view showing a second embodiment of a scalp tensioner according to the invention.  
     [0020]FIGS. 5 and 6 are cross-sectional and perspective views, respectively, showing a third embodiment of a scalp tensioner according to the invention.  
     [0021]FIG. 7 is a perspective view showing a fourth embodiment of a scalp tensioner according to the invention.  
     [0022]FIGS. 8, 9 and  10  are cross-sectional views illustrating using a scalp tensioner according to the fourth embodiment of the invention.  
     [0023]FIGS. 11 and 12 are perspective views showing a fifth embodiment of a scalp tensioner according to the invention.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0024]FIG. 2 is a perspective view of a scalp tensioner according to one preferred embodiment of the invention. As shown in FIG. 2, scalp tensioner  100  includes a pair of support structures  110  generally opposed to each other and formed of a surgically sterilizable material which in this embodiment is light weight aluminum formed into blocks. Each support structure  110  supports a gripping mechanism  120  which in this embodiment is formed of a linear array of stainless steel needles or rods sharpened to a point. Through-holes  115  on support structures  110  slidingly receive guide rods  130 , each having a stop  132  to ensure that the support structures  110  remain on the guide rods  130 . In this embodiment, the stop is a cotter ring but other arrangements, such as a flared end, are also possible. The guide rods are formed from aluminum.  
     [0025] Coil springs  140  form a biasing mechanism for biasing the support structures  110  away from each other yet allowing movement between a closed position in which the support structures are generally close to each other, and an open position which corresponds to a scalp tensioning position. The coil springs  140  are formed of stainless steel and are coaxially mounted around guide rods  130 .  
     [0026]FIG. 2 shows a scalp tensioner in its open position in which an open space, generally designated at  150 , is formed between the support structures  110 . In the open position, the open space permits harvesting of hair grafts from a scalp tensioned by the device.  
     [0027] To use the scalp tensioner shown in FIG. 2, a surgeon grips support structures  110  and moves them to the closed position, against the biasing force of coil springs  140 . Gripping mechanisms  120  are then engaged against the scalp so as to pierce it, and the surgeon&#39;s grip is released. Coil springs  140  thereafter bias the tensioner to its open position, as shown generally in FIG. 3. As seen there, the scalp in the donor region is tensioned laterally outwardly, which causes a thinning of scalp  112  against skull  114 , and a general straightening and alignment of hair grafts  115 . Thereafter, a punch-harvester  10  is aligned over a hair graft, and pushed in a downward direction. Because of the tensioning effected by scalp tensioner  100 , the scalp  112  and the target hair graft  115  do not deform significantly, thereby allowing a clean punch-harvesting of the target graft.  
     [0028]FIG. 4 shows an alternative embodiment of the present invention. As seen in FIG. 4, this embodiment features more than two support structures, in this case three support structures  210 . The support structures are generally opposed, and in this case form a generally triangular open region  250 . Because the FIG. 4 embodiment tensions in three directions rather than the single direction of the FIG. 2 embodiment, superior tensioning may be achieved.  
     [0029] The FIG. 4 embodiment also uses a linear array of teeth as a gripping mechanism. Other gripping mechanisms are also usable, as described below in connection with the embodiment shown in FIGS. 5 and 6.  
     [0030] Various arrangements are also possible in which the gripping mechanism on one support structure differs from the gripping mechanism on another support structure, such as teeth on one support structure and needles on another. It is also possible to arrange one of the support structures to be fixed with respect to its guide rods, with the remaining supporting structures being movable on the guide rods relative to the fixed support structure.  
     [0031]FIGS. 5 and 6 illustrate a further embodiment of the invention in which the biasing mechanism is formed from a geared assembly  330  in which a central gear  331  engages with opposed gear faces  332  and  334  on a pair of opposed guide rods  335 . Using this geared ratchet assembly, support structures  310  are able to move between a closed position and an open position, and be biased in the open position by the geared ratchet assembly  330 .  
     [0032] This embodiment also features a further example of a gripping mechanism, in the form of a hair clamp. In particular, hair clamp  320  clamps uncut hair at the periphery of the donor region of otherwise closely-cut hair, so as to allow the scalp tensioner to adhere to the scalp.  
     [0033]FIG. 7 demonstrates another embodiment of the present invention. As seen in FIG. 7, this embodiment features a biasing mechanism incorporating hinge assembly  760 . Pivoting hinge arms  765  and  766  of hinge assembly  760  attach at hinge pivot  762 . Through-holes  715  in pivoting hinge arms  765  and  766  house opposite ends of coil spring  740  which is coaxially mounted around guide rod  730 . Guide rod  730  has stop  132  to ensure that hinge arm  766  remains on the guide rod  730 .  
     [0034] Support structures  710  are secured perpendicularly to the unhinged free ends of pivoting hinge arms  765  and  766  and are extended in the same direction to be generally opposed to each other. Stationary gripping mechanism guards  770  extend from support structures  710  in a direction opposite the opposing support structure  710  to form a safety partition guarding gripping mechanisms  720 . Moveable gripping mechanism guards  780  are also pivotally attached to support structures  710  to form another safety partition guarding gripping mechanisms  720 . A first moveable gripping mechanism guard arm  782  is pivotally attached the free end of support structures  710 . A second moveable gripping mechanism guard arm  783  is pivotally attached to pivoting hinge arms  765  and  766  opposite the support structures  710 . Moveable gripping mechanism guards  780  are biased to a default position adjacent stationary gripping mechanism guards  770  through attachment to biasing springs  785 . Biasing springs  785  are further secured to biasing spring anchors  787 . Biasing spring anchors  787  are attached to pivoting hinge arms  765  and  766  generally opposite the support structures  710 .  
     [0035] The surface of moveable gripping mechanism guards  780  opposite gripping mechanisms  720  is textured or serrated so as to grip the scalp in a manner that disfavors lateral slipping when biased toward and along the surface of the scalp. Various constructions are also possible in which the moveable gripping mechanism guards  780  are solid, mesh or grill.  
     [0036] To use the embodiment of the scalp tensioner shown in FIG. 7, a surgeon grips support structures  710  and moves them to the closed position, against the biasing force of coil spring  740 . Moveable gripping mechanism guards  780  are then engaged against the scalp and pressure is applied toward the scalp using the tensioner, as generally shown in FIG. 8. The surgeon&#39;s grip biasing the closed position is then released while maintaining the pressure toward the scalp with the tensioner. The coil spring  740  thereafter biases the tensioner toward its open position. The textured surface of the moveable gripping mechanism guards  780  grip the scalp and pivot inward toward one another as the tensioner opens. Gripping mechanisms  720  are exposed and move away from each other along the scalp and lower until contact with the scalp is achieved, as generally shown in FIG. 9. Thus, constant pressure toward the scalp from the tensioner as the coil spring  740  biases the tensioner toward its open position results in the recession of moveable gripping mechanism guards  780  and gripping mechanisms  720  engaging the scalp, as generally shown in FIG. 10 which demonstrates the utilization of a linear array of needles as gripping mechanisms  720 .  
     [0037] Once the surgeon disengages the scalp tensioner from the scalp, the moveable gripping mechanism guards  780  automatically return to their default position baised against stationary gripping mechanism guards  770 .  
     [0038] This embodiment therefore safely covers the gripping mechanisms  720  when not in use as well as allows the surgeon to access the donor region of the scalp from an area perpendicular to the donor region as well as an area lateral to the donor region. This access permits harvesting of hair grafts from a scalp tensioned by the device from multiple directions.  
     [0039]FIG. 11 shows a further embodiment of the invention. As illustrated in FIG. 11, this embodiment features support structures  1110  formed from a band like head brace. Support structures  1110  are integrated with a biasing mechanism incorporating screw assembly  1160 . Screw  1162  is engaged with support structures  1110  through nuts  1165  and  1166 . Gripping mechanisms  1120  are placed at free ends of support structures  1110 .  
     [0040] To use the embodiment of the scalp tensioner shown in FIG. 11, a surgeon unscrews screw  1162 , loosening support structures  1110  to the closed position. The scalp tensioner is then placed circumferentially around the perimeter of head and oriented so that the donor region is accessible between gripping mechanisms  1120 . The surgeon engages gripping mechanisms  1120  with the scalp and screws screw  1162  through nuts  1165  and  1066  contracting support structures  1110  toward each other at screw  1162  and biasing the tensioner toward its open position resulting in tensioning scalp  1112 .  
     [0041] Various arrangements are also possible in which three or more band like support structures encompass various regions of the head providing for numerous gripping mechanism engagement areas.  
     [0042]FIG. 12 illustrates another possible arrangement of this embodiment in which the gripping mechanism  1220  on support structure  1210  is formed from a planar array of needles.  
     [0043] The invention has been described with respect to particular illustrative embodiments. It is to be understood that the invention is not limited to the above-described embodiments and that various changes and modifications may be made by those of ordinary skill in the art without departing from the spirit and scope of the invention. The various embodiments can be combined with each other to yield embodiments different from those shown herein. As one example, a feature or features from one embodiment can be substituted for corresponding features in another embodiment. In particular, gripping mechanisms can be substituted, and they can be substituted asymmetrically such that a gripping mechanism on one support structure differ from that on another support structure. Thus, the invention should not be limited to the disclosed structures but rather should be measured by the appended claims.