Radiolucent orthopedic chuck

A radiolucent orthopedic chuck includes a housing having a driver stem protruding from the top surface and a drill bit protruding from the underside in radially spaced relation from the driver stem so as to displace a drill secured to the driver stem from the axis of the drill bit so that fluoroscopy may be used to ensure accurate alignment of the drill bit with a hole of an intramedullary nail both prior to and during its operation. A drive train interconnects the driver stem and drill bit for rotation in unison. All parts of the chuck but for the drill bit preferably radiolucent.

BACKGROUND OF THE INVENTION 
The present invention is directed generally to a radiolucent orthopedic 
drill chuck which displaces the drill bit sufficiently away from the 
orthopedic drill that x-rays may be directed axially of the bit without 
interference by the drill for prompt and precise alignment and drilling. 
Although the critical applications for the present invention are diverse, 
its conception and prototypic clinical trials have involved intramedullary 
nails. In this country alone, annual tibia surgeries include approximately 
twenty-three thousand closed reductions and one hundred eleven thousand 
open reductions. Femur fractures result annually in approximately 
thirty-three thousand closed reductions and one hundred thirty-one 
thousand open reductions. For femur fractures, an elongated intramedullary 
nail is inserted through the center of the bone from an incision in the 
hip whereupon the nail is stabilized by a single screw inserted through 
the bone and nail at an angle to the axis of the nail. It has long been a 
problem to then accurately drill holes aligned with the holes at the 
distal end of the nail for the interlocking screws. 
The current techniques include various free hand techniques as well as 
techniques using various stationary metal devices. Whereas a fluoroscope 
is used to assist with proper positioning of the drill, all of these 
techniques have in common the necessity for removing the fluoroscopic 
image while drilling. The problem inherent with all of these techniques 
therefore is that they in fact require blind drillings. 
In one manual technique, a large incision is made near the distal end of 
the nail to expose the bone. The surgeon manipulates an awl to mark the 
drilling site on the bone with the aid of a fluoroscopic screen. The 
surgeon gets radiated while positioning the awl. The awl is then set by 
pounding it against the bone. Alternately, the holes may be drilled 
percutaneously by positioning the awl to mark the skin, after which the 
awl is removed and a drill is directed toward the bone through the marked 
spot on the skin. In either event, the double step of first marking the 
drilling location with an awl and then moving the awl and inserting a 
drill increases the chances for error over and above the inherent 
difficulty of blind drilling. 
Certain of the positioning devices afford six degrees of freedom of 
movement but these require much education on the techniques of using the 
machine and still result in blind drilling. 
Olerud, et al., U.S. Pat. No. 4,625,718 discloses an aiming apparatus for a 
wire drill. Whereas this devise enables live action sighting, it has 
several shortcomings which are believed to be resolved by the present 
invention. First, the Olerud apparatus is awkward for a surgeon to use 
since it has two handles on both sides of the fluoroscopic beam. Since the 
head of the x-ray machine is generally positioned about ten inches from 
the drilling site, it is awkward to reach in and manipulate both handles 
simultaneously. It requires the drill to be positioned at a right angle to 
its normal drilling position so that the drill is pushed sideways in an 
unfamiliar manner during use. Secondly, the metal around the opening of 
the Olerud, et al., device is radio opaque which is a big disadvantage for 
sighting. Finally, the Olerud device rotates a wire, not the actual drill 
bit. Since wire burns bone, it is not a good idea to drill bone with it. 
Furthermore, since the diameter of the wire is much smaller than a drill 
bit, it is very difficult to accurately center the wire within the larger 
diameter nail openings. If the wire opening is eccentrically positioned, a 
hollow drill bit following the wire will strike the nail rather than be 
directed through the distal hole as intended. 
Accordingly, a primary object of the invention is to provide a radiolucent 
orthopedic drill chuck which displaces the drill bit from the radio opaque 
drill for live sighting of the drill bit during the operation. 
Another object is to provide a radiolucent orthopedic chuck which protects 
the surgeon's hand from exposure to the fluoroscopic sighting beam. 
Another object is to provide a radiolucent orthopedic chuck which is 
lightweight, simple in construction and readily usable without special 
instruction. 
Another object is to provide a radiolucent orthopedic chuck which enables 
the drilling of a hole for an interlocking screw to be quickly and 
accurately performed thereby reducing trauma to the patient and x-ray 
exposure of the surgeon. 
Another object is to provide a radiolucent orthopedic chuck which is 
substantially entirely radiolucent but for the drilling bit to afford 
optimum sighting in use. 
Another object is to provide a radiolucent orthopedic chuck which is simple 
and rugged in construction, economical to manufacture and efficient in 
operation. 
SUMMARY OF THE INVENTION 
A radiolucent orthopedic chuck is provided for precision drilling of holes 
through which interlocking screws may be accurately directed through the 
distal holes of an intramedullary nail positioned within a bone. The chuck 
includes a housing having a rotatable upright driver stem accessible from 
the top of the housing for attachment to a power drill. A rotatable drill 
bit support device is positioned within the housing for supporting a drill 
bit in upright relation with the bit protruding from the underside of the 
housing at a position radially spaced from the driver stem. A power 
transfer mechanism on the driver stem and drill bit support device rotates 
the drill bit support device in response to rotation of the driver stem. 
Both the housing and drill bit support device are substantially 
radiolucent so that a fluoroscopic beam directed axially of a drill bit 
secured within the drill bit support device is effective both prior to and 
during the actual drilling operation for aligning the drill bit with one 
of the distal holes of an intramedullary nail. The drilling operation is 
thus substantially simplified by combining the aligning and drilling steps 
for reduced trauma to the patient and reduced exposure of the surgeon to 
x-rays. 
The drill bit support device is a radially spaced from the driver stem 
sufficiently that a drill fixed on to the driver stem is displaced from 
the path of the fluoroscopic beam directed axially through a drill bit in 
the drill bit support device. Despite this displacement, it is preferred 
that the driver stem be oriented parallel to the drill bit so that the 
drill and chuck are advanced toward the bone by the same type of motion 
that is used by the surgeon without the chuck of the invention. The drill 
is stationarily secured relative to the chuck by a pair of universal 
brackets on the chuck. Likewise, whereas variances are easily built into 
the chuck, it is preferred that a drill bit supported within the chuck is 
rotated in the same direction as the driver stem and at the rotational 
speed so as to be most similar to that which the surgeon is already 
accustomed. It is furthermore preferred that the drill bit be permanently 
secured to a support collar within the housing and that the housing be 
formed of radiolucent plastic materials so that the entire chuck is 
disposable after each patient use for maintaining optimum sanitary 
conditions for the operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The radiolucent orthopedic chuck 10 of the invention is shown in FIGS. 1, 2 
and 3 including a housing 12 including a top surface 14 and underside 16. 
The housing is formed of top and bottom half sections 18 and 20 which are 
secured together by a plurality of screws 22. The shape of the housing and 
means for affording access to the internal components are not critical to 
the invention and may be designed as desired. For a disposable chuck, the 
housing half sections may be permanently secured together by adhesives or 
the like since access to the components within it would not be required 
for repair or cleaning. 
An upright driver stem 24 seats within a recess 26 and protrudes upwardly 
through an opening 28 in housing top half section 18 for engagement by a 
surgeon's pneumatic drill in the same manner that the drill usually 
receives a drill bit. Stem 24 carries a first gear 30 and spacer 32 for 
rotation within housing chamber 34. 
A drill bit 36 is received within a support collar 38 and is preferably 
permanently secured thereto for rotation in unison. For certain purposes, 
it may be desirable to manufacture a chuck with a replaceable drill bit 
but the sanitation advantages associated with a disposable chuck have been 
given precedence over that feature. Housing bottom half section 20 has a 
circular recess 40 formed therein for receiving a first bearing 42 into 
which the lower end of support collar 38 is received. A second bearing 44 
fits over the upper end of support collar 38 and is received within a 
recess 46 in the housing top half section 18. The second bearing 44 rests 
on a second gear 48 which is permanently fixed onto the drill bit support 
collar 38 for rotation therewith. 
Finally, a small idler gear 50 is carried on a stub shaft 52 receivable 
within aligned recesses 54 and 56 in the housing half sections at a 
position in meshed engagement with both the first and second gears 30 and 
48. Accordingly, rotation of the driver stem 24 in a clockwise direction 
effects a counterclockwise rotation of idler gear 50 which produces a 
clockwise rotation of drill bit 36. It is preferred that the first and 
second gears 30 and 48 have an equal number of teeth so that the rotation 
of the drill bit is in a one to one relation with the rotation of the 
driver stem. 
Referring to FIGS. 12 and 13, each of the first and second bearings 
includes an inner race 58, and outer race 60 and a plurality of balls 
engaged there between. 
The radiolucent orthopedic chuck 10 is adapted for connection to a 
conventional surgical drill 64 as illustrated in FIGS. 18 and 19. The 
conventional chuck 66 of drill 64 simply engages the driver stem 24 as 
illustrated. To secure housing 12 relative to the drill 64, a pair of 
brackets 68 and 70 are secured to housing top wall by a pair of the screws 
22. The L-shaped brackets extend upwardly on opposite sides of the drill 
for detachable securement thereto by a pair of thumbscrews 72. Brackets 
may be designed to accommodate a drill of a particular manufacturer or a 
universal bracket may be provided for securement of any of the most common 
commercial surgical drills. 
The operation of the radiolucent orthopedic chuck of the invention is 
described with reference to FIG. 19. In this illustration, a patient's 
femur 74 is fractured at 76. Whereas only the bone is illustrated, it is 
understood that that bone is incorporated within the leg of a patient 
whose leg is positioned to overlie a fluoroscopic receiver plate 78. After 
insertion of the intramedullary nail 80 in the usual manner and after 
securement of the nail by an inclined screw 82, the leg is positioned so 
that the pair of holes 84 and 86 adjacent the distal end 88 of the nail 
are positioned above and directed perpendicular to the receiver plate 78. 
An x-ray machine head 90 is positioned for directing a fluoroscopic beam 
downwardly through the leg so that the radio opaque nail 80 is visible on 
a fluoroscopic screen 92 of monitor 94. 
All methods of drilling the interlocking screw holes begin with the 
obtainment of perfect circles on the fluoroscopic screen 92. This 
indicates that the axis of the fluoroscopic beam is parallel with the 
central axis 98 between the near and far screw holes 84 and 86 of the 
intramedullary nail 80. 
Once this step is achieved, a skin cut is made and tip 100 of drill bit 36 
is placed down on the near cortex of the bone and manipulated until the 
tip 100 is centered on the respective hole 86 on the fluoroscopic screen 
92. The drill is then rotated upwardly until the axis of the bit 36 is 
collinear with the axis of the respective screw hole 86. This will be seen 
on the screen 92 as the prior perfect circle, representing hole 86, being 
converted to a thin ring of lucency 102. The thickness of the ring is the 
difference between the diameter of the screw hole 86 and the drill bit 36. 
Several still shots or live action, if so desired, may be taken during the 
drilling process to ensure accurate alignment of the drill bit with the 
nail holes 84 and 86. The drill is then depressed in the usual fashion to 
move the drill bit through the bone 74, the respective hole 86 of 
intramedullary nail 80 and into the bone on the opposite side of the nail. 
The drill and chuck are then withdrawn from the leg. During both the 
drilling and withdrawal, the drill is oriented in the usual position for 
drilling so as to be comfortably familiar to even a surgeon who has not 
previously used the chuck of the invention. 
For optimum use of the chuck of the invention, it is preferred that the 
entire housing 12, drill bit support collar 38, first and second gears 30 
and 48 and first and second bearings 42 and 44 all be formed of a 
radiolucent plastic material. Whereas the dimensions of one prototype 
chuck are five inches long by four inches wide by three inches deep, it is 
only important that the length of the chuck be sufficient to displace the 
drill 64 out of the path of x-rays directed through the drill bit 36. 
The chuck of the invention may be used for both holes and any other 
drilling required for a single patient, after which the chuck is disposed 
of for reasons of sanitation. Whereas the drill bit may be formed of hard 
conventional metal material, the remaining parts may be formed of a 
radiolucent plastic material such as polyethylene. More expensive 
ultra-high molecular weight polymers could be used for nondisposable 
chucks having replaceable drill bits. Whereas a three sixteenths drill bit 
is most commonly used for fractures of the femur, a smaller bit is used 
for tibia fractures. 
The radiolucent orthopedic chuck of the invention is a significant 
advantage for orthopedic surgery by combining in a single step the 
aligning and drilling functions, thereby significantly reducing the time 
of the operation resulting in both less trauma to the patient and less 
x-ray exposure to the surgeon. 
Whereas the invention has been shown and described in connection with a 
preferred embodiment thereof, it is understood that many modifications, 
additions and substitutions may be made which are intended within the 
broad scope of the appended claims. 
Thus there has been shown and described a radiolucent orthopedic chuck 
which accomplishes at least all of the stated objects.