DRIVER FOR THE INSERTION AND REMOVAL OF FLEXIBLE FASTENING DEVICES
A driver for inserting and removing flexible and non-flexible fastening devices. The driver has an attachment for interfacing with the proximal end of the device and a flexible driver rod for interfacing with the distal end of the device. Alternatively, the flexible driver rod can interface with both the distal and proximal ends of the fastening device. The driver further interfaces with a guide wire or other means that connect with the interior of the device.
The present invention pertains to drivers for inserting and removing fastening devices and, more particularly, to a driver for inserting and removing flexible fastening devices.
BACKGROUNDThe application of flexible fastening devices encompasses a broad spectrum of industries, included, but not limited to, manufacturing, construction, mining, transportation, agriculture, aviation, automotive, and medical. Flexible fastening devices, either tipped like screws and or flat end like bolts, have the characteristic of the cylindrical portion of the device being bendable about the longitudinal length. Flexible fastening devices are useable in many applications, from manufacturing to medical, to secure two curved, or misaligned, objects together.
In manufacturing and construction, fastening devices are used to join curved members together, to join misaligned holes, to absorb vibration between two components, and numerous other applications. Flexible devices are used to connect two or more members whereby a straight passage of the bolt or device is impossible due to a curved, crooked, or misaligned passage in one or both members. For example, two curved tubes can be connected by inserting a flexible bolt, or device, through the internal diameter of one to thread into the internal diameter of the other tube to join them together.
In the medical industry, flexible devices are particularly useful in the intramedullary fixation of fractured or severed bone fragments. Bone devices are typically used in internal fixation to anchor the fixation system to the relevant bone portions or to join two or more fragments of a fractured bone into close proximity for bone union. For example, devices can be used in plate or rod systems to treat complex fractures of long bones or conditions such as vertebral instability. In small bone fractures, such as the bones of the hands, feet, and wrist, the device is placed across the fracture site to bring the fracture surfaces in close proximity. In medium (clavicle, rib and others) and long (lower and upper extremities) bone fractures, devices can be inserted into the intramedullary canal for minimally invasive fracture reduction.
Various surgical procedures utilize devices to fixate anatomical tissue for healing. An example of a fixation device is a compression bone fixation device, commonly referred to throughout the present description as “compression device”, used to fixate two or more bone fragments or intramedullary fixation of a bone.
A surgical device driver is commonly used to insert bone devices; however, removal can be an issue, especially with flexible devices.
SUMMARY OF THE INVENTIONA driver for insertion and removal of a fastening device is disclosed. The fastening device has a distal end and a proximal end, each having a cross-section configuration. The driver comprises a flexible drive rod with a proximal end, a distal end and a cross-section configuration along its length. The flexible drive rod is selected from the group consisting of Nitinol, spring steel, flexible polymers and flexible composites to provide durability and flexibility. A coupling mechanism with its proximal end part of an extension rod and a distal end a rod receiving area. An extension drive rod connects the handle and the coupling mechanism. The handle can be at right angles to the extension rod or the two can be inline to one another. The flexible rod is configured to interact with at least one of the distal end and proximal end of the fastening device to enable insertion into or removal of the fastening device from an element.
When the fastening device is hollow, the flexible drive rod can extend from the proximal end to the distal end of the fastening device to apply simultaneous rotation to the proximal and distal ends of the fastening device to prevent the fastening device from twisting. The distal and proximal ends of the fastening device of the fastening device have a cross section larger than the cross section of the flexible rod to create a gap between the flexible rod and the distal and proximal ends for torque transmission.
In one embodiment the rod receiving area has a cross section complimentary to the flexible drive rod of the driver to prevent rotation of the rod within the receiving area. In another embodiment the rod receiving area is circular and the flexible drive rod prevented from rotation by locking screws. The extension rod is provided with a hollow channel extend completely or part way through to the outside of the handle and dimensioned to receive the flexible drive rod. Threaded locking screw receiving areas extend from the outer surface of the extension rod to the hollow channel and are dimensioned to receive the locking screws. The locking screws contact the flexible drive rod to prevent its rotation within the rod receiving are and hollow channel.
When the fastening device is flexible it enables the connection of two curved or nonlinear elements. An example of this would be a bone screw where two curved bones are connected.
A method of inserting and removing a flexible fastening device, with a proximal end, a distal end and a channel along its length, comprises the steps of:
a. selecting a flexible drive rod having a cross-sectional configuration complimentary to the periphery of the proximal end and distal ends of the flexible fastening device;
b. inserting said flexible drive rod into the rod receiving area of a coupling mechanism extending from an extension rod affixed to a handle;
c. inserting said flexible rod into a flexible fastening device and engaging the distal end and proximal end of the flexible rod;
d. turning the handle to rotate the flexible fastening device from both said distal end and said proximal end and preventing the flexible fastening device from twisting during insertion and removal.
The flexible drive rod can be prevented from rotating within the rod receiving area by selecting a rod receiving area having a complimentary cross section with the flexible rod. Alternatively, the flexible drive rod can be prevented from rotating within the rod receiving area by selecting a circular rod receiving area and securing the flexible drive rod with locking screws placed within the extension rod.
Preferably the flexible drive rod has a cross section less than the periphery of the distal and proximal ends of the fastening device, creating a gap for torque transmission.
The objects, features, advantages and aspects of the present invention can be better understood with reference to the following detailed description of the preferred embodiments when read in conjunction with the appended drawing figures. All of the figures are drawn on an oversized scale, and like structure in different figures bears like reference numerals.
In
For the purposes herein the term “flexible fastening device” or “device” can be used interchangeably and shall refer to an externally threaded fastener having at least one threaded segment and at least one slotted, flexible segment that may be threaded or unthreaded.
For the purposes herein the term “screw” or “bolt” can be used interchangeably and shall refer to any externally threaded fastener having at least one threaded segment and at least one slotted, flexible segment that may be threaded or unthreaded.
For the purposes herein the term “flexible guide rod” and “flexible guide wire” can be used interchangeably and shall refer to a flexible rod or wire manufactured from a flexible, bio-compatible material.
The present invention addresses the insertion of a flexible fastening device into a curved channel or to secure two unaligned elements. The flexible driver can also be used to insert and remove flexible fastening devices that would twist when driven by only the proximal end through the engagement of both the proximal and distal ends of the fastening device. In addition, the disclosed provides a mechanism or tool to remove a proximal portion of a broken fastening device.
When the interior cavity of the distal end of a broken flexible fastening device has a shape complimentary to the disclosed flexible rod that can be inserted into the cavity from the proximal end, the device can be driven from the distal end. Since the cavity through which the rod must pass to enter the distal end of the broken device, the insertion rod is required to be flexible. The ideal choice of material for this application is Nitinol, a nickel-titanium alloy, although other metallic alloys, such as spring steel, or flexible polymers and composites that meet the criteria set forth herein are applicable. When inserted into the distal cavity, the complimentary rod can be used to rotate the device in a manner that it would back itself out.
In addition to flexibility, the material of manufacture must have the strength to be under high torque without snapping. This is especially applicable when used in industrial applications, and the selection of the appropriate material for the end use will be known to those skilled in the art based on the teachings herein.
Similarly, the drive rod can also be used to insert a flexible fastening device required to connect two elements having a non-linear connection channel, or cavity. Thus, when coupled with a driving attachment to the proximal end of the device, the driver is applying the driving torque to both the distal and proximal ends of the device thus relieving the twisting of the central flexible segment of the device. For exemplary purposes, the cross section of the drive rod and internal complimentary shaped internal cavity are shown as hexagonal, but any complimentary shapes that do not allow rotation relative to one another would be sufficient.
The disclosed driver has a flexible drive rod for rotating the flexible fastening device and advancing it along the longitudinal axis of the driver. The driver cooperatively engages with a drive recess, within the proximal end of the device, to achieve axial alignment of the device with the drive rod of the driver. When use in medical applications where a guide wire is required, the driver prevents rotation of the guide wire over which the device is placed.
Although a T-shaped handle is illustrated herein, the handle can be of any design convenient and that provides sufficient grip for the user. Alternatively, the extension rod and handle can be eliminated, such as illustrated in
The T-handle driver 100, illustrated in
In
In most situations the flexible rod 140 is connected to the coupling mechanism 130 to penetrate the intended fastening device's internal opening to couple with at least the internal distal end of the intended flexible fastening device. This is illustrated and described in more detail hereinafter in conjunction with
In the embodiment illustrated in
In another embodiment shown in
In this embodiment the interior receiving area 188 of the coupling mechanism 186 is circular rather than complimentary with the guide wire 190. To prevent rotation of the guide wire 190, the locking screws 182 and 184 are secured against the guide wire 190.
Removal of the screw 150 would involve placing the guide wire 190 into the screw 150 and then connecting the proximal end of the screw 150 to the extension rod 189. Conversely, to insert the screw 150, or flexible fastening device, into the bone, or other channel, the guide wire 190 would be threaded through the reamed bone, or channel. The screw 150, with the driver 180 attached, would then be inserted along the guide wire 190 and secured by the flexible fastening device threads.
In
In
In another embodiment illustrated in
It can be beneficial in some applications to have the configurations of the coupling mechanism, extension rod and/or flexible rod changed. In these embodiments, additional locking screws can be used within the extension rod to change out the coupling mechanism and/or flexible rod. In applications where the extension rod needs to be changed, the driver would need to be manufactured in two parts and the extension rod extended into, and secured, within the handle using methods known in the art.
Claims
1. A driver for insertion and removal of a fastening device, said fastening device having a distal end, a length, and a proximal end, each of said distal end and proximal end having a cross-section configuration, said driver comprising:
- a. a flexible drive rod, said flexible drive rod having a proximal end, a distal end, and a cross-section configuration along a length;
- b. a coupling mechanism having a proximal end and a rod receiving area;
- c. a handle; and
- d. an extension rod, said extension rod connecting said handle and said coupling mechanism
- wherein said cross-section configuration of said flexible drive rod is configured to interact with said cross-section configuration of said at least one of said distal end and said proximal end of said fastening device to enable said fastening device to be inserted into or removed from at least one element.
2. The driver of claim 1 wherein said fastening device is flexible to enable connection of two of said at least one element having non-linear connection channels.
3. The driver of claim 1 wherein said fastening device has a channel along its length for receiving said flexible drive rod, wherein said flexible drive rod extends from said proximal end to said distal end of said fastening device to apply simultaneous rotation to said proximal end and said distal end of said fastening device.
4. The driver of claim 1 wherein said flexible drive rod is dimensioned to be received within and extend through said proximal end of said fastening device.
5. The driver of claim 1 wherein said coupling mechanism rod receiving area has a cross section complementary to said proximal end of said fastening device.
6. The driver of claim 3 wherein said fastening device is a bone screw.
7. The driver of claim 3 wherein said distal end of said fastening device and said proximal end of said fastening device have a cross section larger than said cross section of said flexible drive rod to create a gap for torque transmission.
8. The driver of claim 1 wherein said rod receiving area is configured to compliment said flexible drive rod cross-section configuration to prevent rotation of said flexible rod.
9. The driver of claim 1 wherein said rod receiving area is circular.
10. The driver of claim 1 wherein said extension rod further comprises a hollow channel and threaded locking screw receiving areas extending from an outer surface of said extension rod to said hollow channel, said hollow channel dimensioned to receive said flexible drive rod and said locking screw receiving areas dimensioned to receive locking screws to secure said guide rod within rod receiving area and said extension rod.
11. The driver of claim 10 wherein said hollow channel extends through said handle to an outer surface of said handle.
12. The driver of claim 10 wherein said rod receiving area is circular and said locking screws prevent rotation of said flexible rod.
13. The driver of claim 1 wherein said flexible drive rod is selected from the group consisting of Nitinol, spring steel, flexible polymers and flexible composites.
14. The driver of claim 1 wherein said extension rod is connected to said handle at right angles.
15. A method of inserting and removing a flexible fastening device having a proximal end, a distal end and a channel along a length comprising the steps of:
- a. selecting a flexible drive rod having a cross-sectional configuration complimentary to a periphery of said proximal end and a periphery of said distal end of said flexible fastening device;
- b. inserting said flexible drive rod into rod receiving area of a coupling mechanism extending from an extension rod affixed to a handle;
- c. inserting said flexible drive rod into said flexible fastening device and engaging said distal end and said proximal end of said flexible rod;
- d. turning said handle to rotate said flexible fastening device from both said distal end and said proximal end;
- wherein rotating said flexible fastening device from said distal end and said proximal end prevents said flexible fastening device from twisting during insertion and removal.
16. The method of claim 15 further comprising the step of preventing said flexible drive rod from rotating within said rod receiving area by selecting a rod receiving area having a complimentary cross section with said flexible drive rod.
17. The method of claim 15 further comprising the step of selecting a flexible drive rod having a cross section less than said periphery of said distal end of said fastening device and said periphery of said proximal end of said fastening device, creating a gap for torque transmission.
18. The method of claim 15 further comprising the step of preventing said flexible drive rod from rotating within said rod receiving area by selecting a circular rod receiving area and securing said flexible drive rod with locking screws placed within said extension rod.
Type: Application
Filed: Mar 13, 2020
Publication Date: Sep 17, 2020
Inventors: William R. Krause (Charlottesville, VA), Daniel W. Christensen (Amherst, VA)
Application Number: 16/818,978