US 3176316 A
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April 6, 1965 B. R. BODELL PLASTIC PROSTHETIC TENDON Filed Jan. 7, 1963 Inventor BRUCE R. BODELL 35/ MM, 611mm zMflaeaw United States Patent 0 3,176,316 PLASTIC PROSTEETIC TENDON Bruce R. Bodeil, 808 PM Ava, River Forest, Ell. Filed Jan. 7, 1963, Ser. No. 249,818 2 Qlaims. (Cl. 3-1) This invention relates to improvements in plastic tendon prostheses and to methods for effecting improved plastic prosthetic tendon grafts. More particularly, the invention is directed to a tendon substitute which by reason of improved structure, especially end structure, and which, by reason of improved suture methods, obviates, in use, many of the undesirable and objectionable features and the shortcomings of prior art devices and techniques.
, Up to the present there have been no completely satisfactory techniques and no uniformly successful procedures by which transected tendons of the fingers could be reapproximated or replaced by autogenous tendon grafts to give normal finger function, particularly when the transection occurs in the area of the middle and proximal phal-anges of the fingers. The principal cause for this I failure has been adherence of scar tissue (at the site of tendon suture) to the sheath which surrounds the tendon. In many instances, the overall result has been immobiliza tion of the tendon. Attempts to prevent adhesion have met with only limited success, and because of these frequent adhesions, neither primary repeir nor delayed autogenous tendon grafting has yielded consistently good funcare also suitable.
Teflon grafts have been used in the prior art, to replace the extensor communis or anterial tibial tendons of dogs. These particular tendons were selected for research, experimentation, investigative work, and testing because,
being covered by sheaths where they pass beneath an extensor retinaculum, they present problems which approximate very closely similar problems which must be considered in dealing with other fiexor tendons, such as tendons of the fingers in the human.
In prior art plastic prosthetic tendon research and investigations, grafts of closely woven or braided Teflon, coated with liquid Teflon to prevent tissue ingrowth, have been used. A bifurcation V was provided at each end of the prosthetic tendon. The arms of the bifurcation were flat bars of limited flexibility. These Y bars were sutured to the tendon ends, either with Teflon or with mattress sutures of 4-0 silk. While these plastic prosthetic tendons and the suturing techniques used have produced encouraging results in initial investigations, they have not been completely successful in several important applications, particularly when directed to transections in the area of the middle and proximal phalanges of the fingers. Frequently, the failures were due to scar tissue which formed at the site of tenton suture, where the bars of the plastic tendons were sutured to the living tendon. This scar tissues adhered to the sheath which surrounds the tendon and the tendon was immobilized.
The principal object of the present invention is to provide an improved prosthetic tendon which is acceptable to and compatible with human tissues and which will glide freely in the tissues to ensure adequate motion of the part controlled.
Another important object is to provide an improved 3,l76,3l6 Patented Apr. 6, 1955 end structure for joining prosthetic tendons to natural living tendons or other tissues.
Still another object of the invention is to provide a prosthetic tendon in which the junction of the prosthetic with the living tendon is at a site away from the tendon sheath.
Related important objects of the present invention are to provide improved overall structures for prosthetic tendons; to provide improved methods of joining prosthetic tendons to living tendons and to muscles and other tissues; to provide an improved prosthetic tendon which can be joined with living tendon in a manner to avoid disruption when usual and ordinary stresses are imposed after healing has occurred; to provide a prosthetic tendon which can be used to replace a transected tendon or a fixed tendon; to provide a prosthetic tendon which may be used to replace not only transected tendons, but which may also be used as a replacement in the case of destruction of tendons anywhere in the body where destruction of the natural tendon, as for example through crushing, burns, or missile injuries, has been so extensive as to preclude reapproximation of the severed ends; and to provide a prosthetic tendon which can be connected to a living tendon in a manner to minimize the formation of motion-impairing scar tissue.
Through a technique of tendon transfer to a nonparalyzed muscle, the prosthesis may be used to restore the function of a body part immobilized by muscle paralysis. It may also be used for manipulating parts of limb prosthesis by connection with body muscles through the artificial tendon.
Other objects, advantages, and utilities of the present invention will become apparent as the detailed description continues and upon consideration of the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same.
FIGURE 1 is a schematic representation of the prosthetic tendon of the invention;
FIGURE 2 is an end view of the prosthesis of the invention taken along the line 22 of FIGURE 1;
FIGURE 3 is an enlarged view of an end detail of the prosthesis of the invention; and
FIGURE 4 is a schematic idealized representation of the manner of suture of the prosthesis to a tendon.
Referring now to FIGURE 1, there is shown, for the purpose of illustrative disclosure, a preferred embodiment of the tendon prosthesis of the invention. The prosthesis, indicated generally at 11, consists of a body in the form of a strong solid or semi-solid flexible shaft 12 having an outer shell or sheath 13 of finely braided, woven, or intertwined inelastic synthetic plastic material such as Teflon, Kel-F, or Silastic, some of the fibers or threads 14 of which continue to and beyond the ends of the principal structure forming an expanding, conically shaped loosely woven casing or sleeve 15 near the ends and terminating, finally, in a plurality of well defined individual or composite strands, threads, or distinct thread-like fibers 16 extending longitudinally beyond the ends of the main portion of the device. Instead of constituting a direct extension of the hollow sleeve or casing 15, the threads may be anchored at a position within the sleeve 15 or even to the shaft portion of the prosthesis. As illustrated in FIG- URE 1, the terminating threads extending outwardly of the ends of the body of the prosthesis proper are four in number. While more than four end threads may be used, if desired, it has been found that four threads are adequate for efiecting a good and a balanced suture bond between the prosthesis of the invention and the natural tendon to which it is connected. Three end threads have provided satisfactory suture bonds, and prosthetic tendons having cial problems in establishing a balanced mechanical stresssupporting bond between the prosthesis and the tendon The flexible shaft portion'12' of the prosthetic tendon maybe of any desired length, depending .upon the particular use and function intended. In cross-section, as depictedin thepreferred embodiment of FIGURE 2, the prosthesis is circular. It may be oval or'elliptical, and in certain cases a shaft having a double-bowed or a fairly flat cross-sectional configuration may be a satisfactory form. In most instances, the shape of the original natural tendon itself will be adapted for the prosthesis. The shaft 'l2 of the prosthetic tendon isof a braided or of a finely woven mesh of a synthetic m aterial such. as Teflon, Kel-F, Silastic, etc; This structural form imparts both flexibility and strength to the tendon. Elasticity is should be longenough to, permit their use as sutures for connecting the prosthetic tendon to the natural tendon.
' A thread length of 3" to 4" is preferred for many applications. Shorter lengths may be used and special uses may require longer terminal-threads.
' While preferred embodiments of the invention'have to be avoided. The shaft maybe essentially solid throughf out the major portion of its length, :but as described and depicted in the drawings, the shaft is formed to provide a loosely woven hollow cylindrical casing or sleeve at either end (see FIGURE 3). It is into this hollow po'r tion 17 or open cylindrical sleeve-that the end 18 of the of livingtendon fibers 20 to form an integral firm and v 1 strong union between the-prosthetic'tendon and the living been provided;-it will be apparent-that numerous modifications and variations thereof maybe without de'parting from underlying principles of'the invention. It is therefore desired by the following claims to include within the scope of the inventionall' such variations and modifications by which substantially the results of thisEinvention may be-obtained through the use of substantially, the same or equivalent means. a Y a What is claimed is: 1 i a l. A tendon prosthesis comprisinga solid central section longitudinally aligned between and integrally joined to hollow end sleeve sections, said central section having an elongatedv substantially inelastic, flexible shaft including a tight mesh .lubric plastic outer sheath portion impenetrable to livingfibers and scar tissue, each said hollow end sleeve section extending longitudinally from" said cenliving tendon 19 is inserted at the time theprosthetic tendon is sutured or otherwise fastened to the natural tral section and having anopen end to'receive therewithin the end of a living tendon, each said hollow end sleeve section being a loose mesh to facilitate ingrowth of living tissue, and each said hollow end sleeve section having a plurality of endwise projecting connection threads for suture into the corresponding tendon for fixingsuchtentendon 19. The bond developed through ingrowth of the a living tendon into the sleeve 15:0f the prosthesis is important in supplementing themechanical bond provided by suturing the plastic end-threads" 16-or fibers of'thei prosthetic tendon to the end 18 of the living tendon 19.
' WhileQas is apparent from the above discussion, it is, important to encourage ingrowth of natural tendon fibers" atthe ends of the prosthetic tendon,]that is, withinthe sleeve 15, :it is essential that ingrowth of tissues into the shaft portion 12 of the prosthesis be avoided and that the shaft be smooth and fiber-impervious. The outer sheath shaft by natural fibers and tissuesh Inorder to provide a still'smoother and more impervious outer surface a coat- 13'is tightly woven or braided to preclude invasion of, the
don to the prosthesis while living tissue ingrows in the loose mesh to form a secure bond,
. 2.;A-tendon prosthesis comprising a: solid central-section longitudinally aligned between and i'nte grally joined to hollow end sleeve sections, saidcentral section 'provid ing an elongated substantially inelastic,fflexible shaft and 1 comprising "a large number of interwoven 'lubi'ic plastic threads defining a 't'ight mesh outer sheath portion impenetrable to living fibers and scartissue, with only some of said threads continuing endwisein each direction from said central section to-constitute each end section as a loose mesh sleeve having'a main length region to facilitate ingrowth of living tissue and having an ,open end to receive therewithin the endof a living tendon, and
Y several of the threads comprising each said hollow end The overall diameter of the shaft 12 will be dictated by the dimensions of the particular natural tendoni with which it is to be associated 'or which it is to replace in whole or in part. Ordinarily. the thickness or the diameter willbe" in the order of to /1 inch; The length ofjithe 7 loosely woven sleeve or hollowed end portion 15 of the prosthesisshould be sufficient to receive the natural tendon segment 22' which isrto be inserted; Ordinarily, a; length of about A to about of an inch .is sufiicient'.
For larger tendons, longer. sleeves are to be preferred.
The terminal threads or strands 16 of the prosthesis sleeve section continuing therebeyond fonsuture into the,
corresponding tendon for fixingsuch'tendon to the prosform a secure bond;
'thesis whileliving tissue ingrows in the loose mesh to References Cited by the Examiner 7 UNITEDSTATES PATENTS V 8/38 1 Bowen 3-1 OTHER REFERENCES Williams: Teflon as a Tendon Substitute, from Surgical Forum,'vol. XI, October 1960, pp...'39-40.
RICHARD A. GAUDET, Primary Examiner,