Apparatus and method for securing bone graft

A fastener for securing bone graft between a pair of bone portions. The fastener includes a curved elongated member having a shank for extending into the bone graft and pair of bone portions. The shank has an end portion which receives a force for driving the shank into the pair of bone portions and the bone graft. The shank has a plurality barbs projecting therefrom for resisting movement of the shank relative to the bone graft and the bone portions.

BACKGROUND OF THE INVENTION 
The present invention relates to securing bone graft between a pair of bone 
portions, and in particular, relates to a fastener for securing bone graft 
between a pair of bone portions. 
It is known that bone graft contracts as it resorbs. This characteristic of 
bone graft has resulted in difficulties in securing bone graft between 
spaced apart bone portions which are to be connected by the bone graft. 
Typically, staples are used to secure bone graft between bone portions. As 
the bone graft resorbs, it applies a force to a leg of the staple. The 
force acts through a moment arm and causes the leg to pivot relative to a 
portion of the staple base. This causes the staple to loose its 
effectiveness. 
SUMMARY OF THE PRESENT INVENTION 
The present invention is directed to a fastener for securing bone graft 
between a pair of bone portion. The fastener embodying the present 
invention comprises a curved elongated member having a shank for extending 
into the bone graft and the pair of bone portions to secure the bone graft 
and pair of bone portions together. The shank extends through the bone 
graft in a direction along a line extending through the bone graft and 
bone portions and along which the bone graft resorbs. Thus, the force 
applied to the shank by the bone graft as it resorbs acts generally along 
the longitudinal extent of the shank. Thus, the force does not act through 
a moment arm nor does it have a detrimental effect on the fastener. 
The shank has an end portion for receiving force for driving the shank into 
the pair of bone portions and the bone graft. Since the shank is curved, 
it may be driven into one bone portion through a surface thereof which may 
extend transversely relative to a surface of the bone graft through which 
the shank will extend. As it progresses through the bone portion it moves 
in a curved path into the bone graft and then into the other bone portion. 
The shank has barbs extending therefrom to resist movement of the shank 
relative to the bone graft and the bone portions once it has been driven 
into place. 
The shank also has an opening extending through the end portion for 
receiving a member such as a wire. Thus, it is possible to secure the bone 
graft and bone portions with two fasteners one of which is driven into the 
bone portions and bone graft in one direction and the other of which is 
driven into the bone portions and bone graft in the opposite direction. 
The wire can interconnect the opposite end portion of the respective 
fasteners and assist in retaining the fasteners in position. Specifically, 
if one of the fasteners tends to move out of the bone portions in a 
direction, opposite the direction in which it was driven, it would be 
resisted by the other fastener which would have to move in the same 
direction it was driven and further into the bone portions.

DESCRIPTION OF A PREFERRED EMBODIMENT 
It is well known that bone graft when located between a pair of bone 
portions contracts as it resorbs. This creates problems in securing the 
bone graft in position between the bone portions. A variety of different 
techniques have been utilized to secure bone graft between bone portions. 
The present invention is directed to a simple yet extremely effective 
fastener for securing bone graft in position between a pair of bone 
portions to be interconnected by the bone graft. 
An elongated curved fastener 10 embodying the present invention is 
illustrated in FIGS. 1-3. The fastener 10 includes a shank portion 12. The 
shank portion 12 has a pointed end 14 and at its opposite end has a 
driving head portion 16. A plurality of barbs 20 are spaced along the 
shank portion 12 and project therefrom. 
The fastener 10 is preferably made from a metal material which is 
compatible with human tissue. Such a metal material may be titanium or 
surgical grade stainless steel. 
The pointed end 14 of the fastener 10 is placed in contact with a surface 
22a of a bone portion 22 (FIG. 5). The fastener 10 is driven into the bone 
portion 22. As the fastener 10 is driven into the bone portion, due to its 
curved configuration, it progresses along a curved path A through the bone 
graft 24 and into bone portion 26. The part of the shank portion 12 which 
extends through the bone graft 24 lies along a line B which extends 
generally in the direction in which the bone graft resorbs. Thus, the bone 
graft 24, as it resorbs, applies a force on the shank portion 12 which 
acts generally along the path A of the shank portion 12. 
Each of the barbs 20 on the shank portion 12 have a width W (FIG. 2) which 
progressively increases as the barbs 20 extend in a direction along the 
path A opposite the direction in which the fastener is driven. Thus, the 
fastener 10 appears to be tapered, as viewed in FIGS. 2 and 3, from its 
end portion 14 and increases in width to the end portion 16 of the shank 
portion 12. Also, the barbs 20 have surfaces 25 which are inclined 
rearwardly. The surfaces 25 extend in a direction forming an acute angle 
with the path A along which the fastener is driven. The surfaces 25 are 
inclined to resist withdrawal of the fastener 10 from the bone portions 
22, 36 and the bone graft 24 in a direction opposite the path A along 
which the fastener is driven. 
The end 16 of the shank portion of the fastener includes a pair of opposite 
V-shaped grooves 30, 32. The grooves 30, 32 are adapted to receive 
gripping jaws 40, 42 respectively, of a driving tool 38 (FIG. 7). The tool 
38 holds and drives the fastener 10 into the bone portions 22, 26 and bone 
graft 24. The tool 38 includes the gripping jaws 40, 42, which are 
pivotally attached at pivot 44. A ratchet locking mechanism 46 locks the 
jaws 40, 42 in the grooves 30, 32. The fastener 10 is thus gripped in the 
jaws 40, 42. The driving tool 43 further includes a surface 48 which may 
be struck with a hammer to drive the fastener 10 into the bone portions 
22, 26 and the bone graft 24. 
The manner and the various locations in the body in which a fastener 
embodying the present invention may be utilized are numerous. FIGS. 4 and 
5 show one specific arrangement in which a pair of fasteners 50, 52 
embodying the present invention are driven into bone portions 22, 26 and 
bone graft 24 located therebetween. The procedure of which is described 
below. 
The fastener 50 is inserted between the fibrocartilaginous disk 60b and 
surface 22a of bone portion 22. The pointed end portion 62 of the fastener 
50 is driven through the surface 22a of the bone portion 22 by a driving 
force transmitted through a suitable tool, such as the driving tool 38 
(FIG. 7). The pointed end portion 62 of the fastener 50 is driven through 
the bone portion 22 and exits the bone portion through surface 22b. The 
surface 22b of the bone portion extends in substantially the same 
direction as surface 22a. The pointed end portion 62 of the fastener 50 is 
then driven through the entire thickness of the bone graft 24 and into the 
bone portion 26 through surface 26b. The pointed end portion 62 of the 
fastener 50 is stopped within the bone portion 26. The barbs 64 of the 
fastener 50 resist movement of the fastener in a direction along the path 
A opposite to the direction in which the fastener was driven. 
The end portion 66 of the fastener 52 is similarly driven in a direction 
opposite the direction in which fastener 50 was driven. The fastener 52 is 
spaced laterally from fastener 50 in the bone portions and extends 
completely through the bone portion 26 between surfaces 26a and 26b and 
the bone graft 24. The end portion 66 of the fastener 52 is stopped within 
the bone portion 22. The barbs 68 of the fastener 52 resist movement in a 
direction opposite the direction in which the fastener 52 was driven. 
After the fasteners 50, 52 have been driven into the bone portions 22, 26 
and the bone graft 24 a wire cable 70 is placed through openings 71 in the 
driving ends of the respective fasteners 50, 52. The wire cable 70 is made 
from a material compatible with human tissue, such as braided surgical 
grade stainless steel fibers. The ends 70a, 70b of wire cable 70 are 
secured together by a suitable connector 72. 
The connector 72 is made of a material which can be deformed or crimped to 
frictionally engage the ends 70a, 70b of the wire cable 70 and maintain 
the ends of the wire cable 70 in a desired position relative to one 
another. The connector 72 has a portion 74 which is split extending 
longitudinally of the length of the connector. The ends 70a, 70b are 
placed within the split portion 74 in the desired relative position. The 
connector is then deformed or crimped by a suitable tool to maintain the 
wire cable in a desired tension. 
The fastener 50 is driven into the bone portions 22, 26 and bone graft 24 
in the direction A. The fastener 52 is driven into the bone portions 22, 
26 and the bone graft 24 in the direction A'. If the fastener 50 tends to 
withdraw from the bone portions 22, 26 and bone graft 24 in a direction 
opposite the direction in which it was driven, it would tend to pull the 
fastener 52 further into the bone portions 22, 26 due to the wire cable 70 
which innerconnects the ends of the fasteners 50, 52. This obviously would 
occur also if the fastener 52 tended to withdraw from the bone portions 
22, 26 and bone graft 24. The withdrawal of fastener 52 would be resisted 
by the fastener 50 and the wire cable 70 which innerconnects the 
fasteners. Thus, this attachment of the bone portions 22, 26 and the bone 
graft 24 is made extremely reliable. 
Further it should be apparent that the fasteners 10 also have an opening 80 
at the end 12 thereof. As a result, a wire can be inserted between the 
opposite ends of the fastener. Further, if desired the fastener can be 
used with a tapered locking pin 82 in addition to the wire cable or the 
tapered locking pin may be used alone to lock the fastener 10 in position. 
Such an embodiment is illustrated in FIG. 6. 
Also shown in FIG. 6 is a modified type of mounting of the fasteners. In 
this alternative embodiment, the fasteners 90, 92 secure the bone graft 94 
between bone portions 100, 102. The fastener 90 extends through the bone 
portion 100 between surfaces 100a, 100b of the bone portion. The surfaces 
100a, 100b of the bone portion 100 are disposed adjacent one another and 
extend transversely relative to one another. The fastener 92 extends 
through the bone portion 102 between the surfaces 102a, 102b. The surfaces 
102a, 102b of the bone portion 102 are disposed adjacent one another and 
extend transversely relative to one another. 
A fastener 110 made in accordance with a second embodiment of the present 
invention is illustrated in FIGS. 8 and 9. The fastener 110 is an elongate 
curved member having a rectangular cross section. The fastener 110 
includes a shank portion 112. The shank portion 112 has a pointed leading 
end portion 114 and an end portion 116. The end portion 116 receives a 
driving force to drive the fastener 110 into a bone portion. The fastener 
110 is preferably made of a metal which is compatible with human tissue. 
Such a metal material may be titanium or surgical grade stainless steel. 
A plurality of barbs 120 extend away from a convex surface 118 of the shank 
portion 112 of the fastener 110. The barbs 120 are shaped to permit the 
fastener 110 to be easily driven into a bone portion. The shape of the 
barbs 120 also aids in resisting movement of the fastener 110 outwardly 
from the bone portion in a direction opposite to the direction in which it 
was driven. 
A plurality of ridges 122 are disposed along the concave surface 124 of the 
fastener 110. Each of the ridges 122 extend transversely to the 
longitudinal axis of the shank portion 112. The ridges 122 further aid in 
preventing the fastener 110 from moving relative to a bone portion. The 
ridges 122 extend a lesser distance away from the shank portion 112 than 
the barbs 120 extend. 
The fastener 110 includes an opening 132 for receiving a wire therethrough 
to connect a pair of fasteners together, as described above. The fastener 
110 also includes a second opening 134 extending through the pointed end 
portion 114. The opening 34 may receive a tapered pin, as described above, 
for further securing the fastener 110 from movement relative to a bone 
portion. 
It should be apparent that certain modifications, changes and adaptations 
may be made in the present invention and it is intended to cover all such 
changes, modifications and adaptations which come within the scope of the 
appended claims.