TIGHTENING DEVICE FOR SPINE SURGERY
A device for spinal surgery that may be used for tightening a locking cap onto at least a portion of a pedicle screw. The device may include a torque-generating body having a proximal end and an opposing distal end and a drive shaft rotatably driven by the torque-generating body. A proximal end of the drive shaft may be operatively engaged to the distal end of the torque-generating body and an opposing distal end of the drive shaft may engage at least a portion of one of the locking cap and the pedicle screw. An anti-torque device is provided that has an elongated and generally hollow member defining a longitudinal axis. The member has a proximal end and an opposing distal end, where the proximal end of the anti-torque device may be fixed from rotating relative to at least a portion of the torque-generating body and the distal end may be fixed from rotating relative to a spine rod or a pedicle screw.
The present invention claims priority to U.S. Provisional Application No. 61/278,671, filed Oct. 9, 2009, and entitled “Anti-Torque Device for Spine Surgery,” which is incorporated herein by reference in its entirety.
BACKGROUNDThe present invention relates to an apparatus and method for performing spine surgery and, more particularly, to a tightening device that may be used for, e.g., spinal surgery that includes an anti-torque or zero-torque device for securing a locking cap or nut to a body of a pedicle screw during spine surgery and a method of using same.
Referring to prior art
In
The natural aging process can cause a deterioration of the intervertebral disks and, therefore, their intrinsic support, strength and stability is diminished. Sudden movements may cause a disk to rupture or herniate. A herniation of the disk is primarily a problem when the nucleus pulposus protrudes or ruptures into the spinal canal 108 placing pressure on nerves, which in turn causes spasms, tingling, numbness, and/or pain in one or more parts of the body, depending on the nerves involved. Further deterioration of the disk can cause the damaged disk to lose height and as bone spurs develop on the vertebrae 100, result in a narrowing of the spinal canal 108 and foramen 111, and thereby causes pressure on the nerves emanating from the spinal cord 128.
Presently, there are several techniques, in addition to non-surgical treatments, for relieving the symptoms related to intervertebral disk deterioration. Surgical options include chemonucleolysis, laminectomy, diskectomy, microdiskectomy, and spinal fusion. After spine surgery, adjacent vertebrae 100 may require a fixation system to be clamped to the side where the surgeon accessed the gap between the vertebrae 100. As seen in
As seen in prior art
The above-identified method of tightening the locking cap 148, rod 147 and pedicle screw 146 requires a relatively large locking torque TL, requires the surgeon or other user to employ both hands and may require significant physical effort by the surgeon. As a result, this method often causes fatigue to the surgeon, especially considering that this method may be performed toward the end of a long day of surgery or at the end of a long surgery that attaches a plurality of screws. Furthermore, it can be difficult to produce a perfectly balanced reaction torque TR, which helps to eliminate additional injury to the patient. In addition, applying the reaction torque TR may lead to an excessive force load on the screwdriver 130, the anti-torque device 140 and/or connecting soft tissue of the patient, which may result in additional injury to the patient.
Therefore, it would be desirable to provide an anti-torque device for spine surgery that overcomes the above-identified deficiencies. Specifically, it would be desirable to provide an anti-torque device that rotatably fixedly and axially removably attaches to at least a portion of a torque-generating body, such as a hand-actuated screwdriver or electric power driver, that allows a surgeon or other user to apply a locking torque and generate a generally equal and opposite reaction torque to the pedicle screw, locking cap and/or fixation rod with only a single hand.
SUMMARYA device for spinal surgery that may be used for, e.g., tightening a locking cap onto at least a portion of a pedicle screw. In some implementations, the device may include a torque-generating body having a proximal end and an opposing distal end and a drive shaft rotatably driven by the torque-generating body. A proximal end of the drive shaft may be operatively engaged to the distal end of the torque-generating body and an opposing distal end of the drive shaft may engage at least a portion of one of the locking cap and the pedicle screw. An anti-torque device is provided that has an elongated and generally hollow member defining a longitudinal axis. The member has a proximal end and an opposing distal end, where the proximal end of the anti-torque device may be fixed from rotating relative to at least a portion of the torque-generating body.
In other implementations, there is provided an anti-torque device for spinal surgery that includes an elongated and generally hollow member defining a longitudinal axis, the member having a proximal end and an opposing distal end. The proximal end is fixed from rotating relative to a portion of a torque-generating body and the distal end is fixed from rotating relative to at least a portion of one of a pedicle screw, a locking cap, a fixation rod and a clamp.
In yet other implementations, there is provided a method of tightening a locking cap onto a pedicle screw during spine surgery. The method may include providing a torque-generating body having a drive shaft rotatably attached thereto; engaging at least a portion of a drive shaft with a locking cap; rotatably fixedly attaching a first end of an anti-torque device to at least a portion of the torque-generating body; rotatably fixedly attaching a second end of the anti-torque device to at least a portion of one of a pedicle screw, the locking cap, a fixation rod and a clamp; and rotating the drive shaft to apply a locking torque to one of the locking cap and pedicle screw to generate an equal and opposite reaction torque to one of the pedicle screw, the locking cap, the fixation rod and the clamp.
In some implementations, there is provided a surgical device that includes a torque-generating body having a proximal end and an opposing distal end and a gearbox that receives an input torque from the torque-generating body and provides an increased output torque to a drive shaft to rotatably drive the drive shaft. A proximal end of the drive shaft may be operatively engaged to the gearbox and an opposing distal end of the drive shaft engaging at least a portion of one of a locking cap and a pedicle screw. An anti-torque device may be provided that is comprised of an elongated and generally hollow member defining a longitudinal axis. The member has a proximal end and an opposing distal end, where the proximal end of the anti-torque device may be slidably engaged to the gearbox and fixed from rotating relative to at least a portion of the torque-generating body.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
The foregoing summary, as well as the following detailed description of embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, several implementations are shown in the drawings. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:
Certain terminology is used in the following description for convenience only and is not limiting. The words “right,” “left,” “upper,” and “lower” designate directions in the drawings to which reference is made. The words “anterior,” “posterior,” “superior,” “inferior” and related words and/or phrases designate preferred positions and locations in the human body to which reference is made and are not meant to be limiting. The words “first” and “second” designate an order of operations in the drawings to which reference is made, but do not limit these steps to the exact order described. The words “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the object(s) described herein and designated parts thereof. Additionally, the terms “a,” “an” and “the,” as used in the specification, mean “at least one.” The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import.
Referring to the drawings in detail, wherein like numerals indicate like elements throughout, there is shown in
The fixation rod 17 is an internally-mounted device, with respect to a patient, for fixing two or more adjacent vertebrae after a surgical procedure such as installing a fusion cage (not shown) and the like. The pedicle screw 16 preferably includes a bone screw, thread or anchor 16a at a distal portion and a machine or other mating thread (not shown) at a proximal portion or body 16b. The proximal portion of the pedicle screw 16 may define a U-shaped groove and the machine thread is preferably adapted to receive at least a portion of the treaded cap 18. The pedicle screw 16 may be polyaxial or monoaxial. For the sake of brevity, specific discussion of mounting the pedicle screw(s) 16, cap(s) 18 and fixation rod 17 is omitted herein. Those of ordinary skill in the art recognize how the pedicle screw(s) 16 is/are attached to a vertebrae 100, how the fixation rod 17 is attached to the pedicle screw(s) 16, and how the locking cap 18 is attached to each pedicle screw 16. The pedicle screw(s) 16, fixation rod 17 and locking cap 18 generally comprise an internal fixation system for securing together adjacent vertebrae 100.
Referring again to
The drive shaft 14 is preferably rotatably attached to at least a portion of the torque-generating body 12 and is rotatably driven by the torque-generating body 12. However, in the embodiment employing a hand-actuated screwdriver, the drive shaft 14 may be fixedly attached to the handle of the screwdriver. In the present embodiment, a proximal end 14a of the drive shaft 14 is operatively, and preferably rotatably, engaged to the distal end 12b of the torque-generating body 12 and an opposing distal end 14b of the drive shaft 14 engages at least a portion of one of the locking cap 18 and pedicle screw 16. The drive shaft 14 preferably defines a longitudinal axis 13 between the proximal and distal ends 14a, 14b.
Preferably, the anti-torque device 10 is an elongated and generally hollow member that defines a longitudinal axis 15 generally extending from a first or proximal end 10a of the anti-torque device 10 to an opposing second or distal end 10b of the anti-torque device 10. The proximal end 10a of the anti-torque device 10 is preferably rotatably fixedly attached to and/or fixed from rotating relative to at least a portion of the torque-generating body 12 so as to not rotate with the drive shaft 14. However, the proximal end 10a is preferably not axially and/or pivotally fixed to the torque-generating body 12, such that the anti-torque device 10 is removably attached to the torque-generating body 12.
The distal end 10b of the anti-torque device 10 is preferably rotatably fixedly attached to and/or fixed from rotating relative to at least a portion of one of the pedicle screw 16, locking cap 18 and the fixation rod 17. However, the distal end 10b is preferably not axially and/or pivotally fixed to one of the pedicle screw 16, locking cap 18 and the fixation rod 17, such that the anti-torque device 10 is removably attached to the pedicle screw 16, locking cap 18 and the fixation rod 17.
As seen in
An interior surface of the distal end 10b of the anti-torque device 10 may include one or more generally equally spaced-apart recesses, notches, lugs and/or ridges (not shown) that extend generally perpendicularly therefrom to engage at least a portion of one of the pedicle screw 16, locking cap 18 and the fixation rod 17. Alternatively or additionally, the distal end 10b of the anti-torque device 10 may have a generally ovular or not-perfectly-circular cross-sectional shape to engage at least a portion of one of the pedicle screw 16, locking cap 18 and the fixation rod 17. In the present embodiment, the anti-torque device 10 generally surrounds at least a portion of the drive shaft 14, such that the longitudinal axis 13, 15 of each are parallel and/or coincide.
The anti-torque device 10 may be designed to selectively accommodate either a power driver, as shown in
The torque-generating body 12 may include a clutch (not shown) to release the torque to disengage the torque-generating body 12 from the pedicle screw 16 and/or locking cap 18. The clutch may be selectively manually operated by the surgeon through a push button (not shown) or may be automatically activated to set the torque applied by the torque-generating body 12 at or close to zero.
Most, if not all, components of the anti-torque device 10 and the torque-generating body 12 are formed of a high-strength material, such as a metallic material. For example, in the embodiment, the anti-torque device 10 and at least the drive shaft 14 of the torque-generating body 12 are formed of a type of stainless steel. However, the anti-torque device 10 and the torque-generating body 12 are not limited to such materials. For example, alternate materials may include titanium and its alloys, aluminum and its alloys, polymers, phenolic and/or silicone.
Tightening the treaded cap 18 onto a pedicle screw 16 may be done as follows:
(i) mounting a first end of the fixation rod 17 to one pedicle screw 16 and mounting a second end of the fixation rod 17 to another pedicle screw 16;
(ii) mounting the locking cap 18 onto each pedicle screw 16 over the fixation rod 17;
(iii) attaching the distal end 14b of the drive shaft 14 of the torque-generating body 10 to at least a portion of one of the locking cap 18 and pedicle screw 16;
(iv) attaching the distal end 10b of the anti-torque device 10 to at least a portion of one of the pedicle screw 16, a portion of the locking cap 18, the fixation rod 17 or virtually any other structure fixedly secured to one of the screw 16, cap 18 and/or rod 17; and
(v) rotating the drive shaft 14 (i.e., clockwise) to apply a locking torque TL to the locking cap 14, while preventing the pedicle screw 16 from rotating, thereby generating an equal and opposite reaction torque TR (i.e., counterclockwise) to the pedicle screw 16 or fixation rod 17.
The procedure may be performed with working channels or tubes that include a slot at the distal-most portion of the working channels or tubes for facilitating the complex dexterous work to be performed, such as screwing in the pedicle screws 16, fixation rods 17 and/or tightening mounting hardware, such as the locking caps 18 and the like.
Referring to
In this embodiment, a first gear 24a′ is operatively connected to a distal end of the torque limiting mechanism 24′ and operatively engages a first spur gear 28′. The first spur gear 28′ preferably has twice the number of gear teeth as the first gear 24a′, such as a twenty (20) to ten (10) gear tooth ratio. A spur 28a′ of the first spur gear 28′ operatively engages a second spur gear 28′. The second spur gear 28′ preferably has twice the number of gear teeth as the spur 28a′ of the first spur gear 28′, such as a twenty (20) to ten (10) gear tooth ratio. The proximal end 14a′ of the drive shaft 14′ is operatively engaged with the second spur gear 28′. In an embodiment, at least a portion of the proximal end 14a′ of the drive shaft 14′ extends through at least a central portion of the second spur gear 28′ and is fixedly connected thereto, such that rotation of the second spur gear 28′ directly rotates the drive shaft 14′. Thus, rotation of the first gear 24a′ by or through the torque limiting mechanism 24′ rotates the drive shaft 14′ and increases the torque applied by the surgeon. In some implementations, the overall gear ratio of the gearbox maybe 4-to-1, with a range between 2-to-1 and 10-to-1.
As with the first embodiment, a proximal end 10a′ of the anti-torque device 10′ is preferably rotatably fixedly attached to at least a portion of the torque-generating body 12′. A distal end 10b′ of the anti-torque device 10′ preferably rotatably fixedly attaches to one of a pedicle screw 16, and fixation rod 17 that is part of the internal fixation system. In operation, rotation of the T-shaped handle 22′ rotates the drive shaft 14′ with respect to the anti-torque device 10′. Thus, the drive shaft 14′ applies a locking torque on one of the locking cap 18 and the pedicle screw 16, while the anti-torque device 10′ prevents the pedicle screw 16 from rotating and, thus, a generally equal and opposite reaction torque is applied to at least one of the pedicle screw 16, locking cap 18, fixation rod 17 and clamp. As with the first embodiment, the above-identified structure of the second embodiment allows the user to accomplish proper tightening of the locking cap 18 to the pedicle screw 16 with only a single hand.
As seen in
Referring to
The anti-torque device 10″ may include a handle 34″ that defines a longitudinal axis that preferably extends generally perpendicularly from a longitudinal axis 15″ defined by an elongated and generally hollow member 36″. The handle 34″ is not a necessary component and is merely provided in the instance of replacing the power tool with a hand-actuated screwdriver or in providing an additional holding/carrying feature for the surgeon. A proximal end 10a″ of the hollow member 36″ preferably includes an eye 38″ having an eccentrically-shaped interior surface. In the present embodiment, the interior surface of at least a portion of the eye 38″ is octagonally-shaped and is sized to matingly receive at least a portion of the motor shaft 20″, which also preferably includes an exterior surface that is octagonally-shaped.
In operation, the user initially inserts the distal end 14b″ of the drive shaft 14″ into the proximal end 10a″ of the hollow member 36″ of the anti-torque device 10″ (see
Once power is supplied to the torque-generating body 12″, the drive shaft 14″ applies a locking torque on one of the locking cap (not shown in
Referring to
In the fourth embodiment, an input drive axis 23′″, as defined by the shaft connecting the T-shaped handle 22′″ to the worm gear 40′″, is roughly perpendicular to a longitudinal axis 13′″ of a drive shaft 14′″. Thus, all of the torque applied through the drive shaft 14′″ is balanced by a distal end 10b′″ of a hollow member 36′″ of the anti-torque device 10′″ and little or no net torque is applied to the pedicle screw. The anti-torque device 10′″ of the present embodiment preferably includes archways 30′″ and operates in a similar manner to the anti-torque device 10′ of the second embodiment described above. The anti-torque device 10′″ may include a handle 34′″, which preferably extends generally perpendicularly from the shaft of the T-shaped handle 22′″ and serves a similar purpose to the handle 34″ of the third embodiment described above. In a variation of the forth embodiment, the worm gear arrangement is replaced by a set of bevel gears to accomplish the same effect of gear reduction while lowering the friction inherent in the use of bevel gears.
Referring to
In operation, as a distal end 14biv of the drive shaft 14iv is engaged with one of a pedicle screw (not shown in
Referring to
In this embodiment, the distal end 222a of the input handle 222 engages a notched shaft 226 that is connected to a first gear 24av (
As shown in
A proximal end 10av of the anti-torque device 10v is slidably attached to a portion of the torque-generating body 12v. As such, the anti-torque device 10v may slide in the longitudinal direction for engagement, but is not able to rotate about the torque-generating body 12v. The proximal end 10av may be provided with a grip pattern, as shown in
In operation, rotation of the handle 222 rotates the drive shaft 14v with respect to the anti-torque device 10v. Thus, the drive shaft 14v applies a locking torque on one of the locking cap 18 and the pedicle screw 16. Meanwhile the anti-torque device 10v, as fixed by the cooperation of the keyed interface 232 and the face 230, prevents the pedicle screw 16 from rotating and, thus, a generally equal and opposite reaction torque is applied to at least one of the pedicle screw 16, locking cap 18, fixation rod 17. The above-identified structure of the fifth embodiment allows the user to accomplish proper tightening of the locking cap 18 to the pedicle screw 16 with only a single hand.
As seen in
It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. For example, the embodiments shown typically engage pedicle screws, nuts and/or rods used in the thoracic and lumbar spine. However, other applications in the spine may include pedicle screws, nuts and/or rods used in the cervical spine, pedicle hooks used in the cervical, thoracic or lumbar spine, plates or fixation rods used in anterior or lateral fixation of the spine, a vertical expandable rib, transconnectors as used as part of a spine rod construct, transverse bars as used as part of a spine rod construct, rod-to-rod connectors as used as part of a spine rod construct, and setscrews used in holding an end position in distractable devices such as vertebral interbody spacers and interspinous process spacers. Further, other applications may be tightening of locking screws or nuts used in bone fixation in various regions of the human body. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the present disclosure.
Claims
1. A system for tightening a locking cap onto at least a portion of a pedicle screw during spinal surgery, the system comprising:
- a torque-generating body including an elongated shaft having a proximal end and an opposing distal end and defining a longitudinal axis extending therebetween, the distal end of the elongated shaft coupled to a handle;
- a drive shaft rotatably driven by the torque-generating body, the drive shaft having a proximal end, an opposing distal end and a longitudinal axis extending therebetween, the proximal end of the drive shaft being operatively engaged to the distal end of the torque-generating body such that the longitudinal axis of the torque-generating body extends in a direction away from a longitudinal axis of a drive shaft, the opposing distal end of the drive shaft engaging at least a portion of one of a locking cap and the pedicle screw; and
- an anti-torque device comprised of an elongated and generally hollow member defining a longitudinal axis, the member having a proximal end and an opposing distal end, the proximal end of the anti-torque device being fixed from rotating relative to at least a portion of the torque-generating body,
- wherein the drive shaft is operatively engaged with the torque-generating body such that rotational movement of the elongated shaft about the longitudinal axis of the torque-generating body translates into rotational movement of the drive shaft about the longitudinal axis of the drive shaft.
2. The system of claim 1, wherein the distal end of the anti-torque device is fixed from rotating relative to at least a portion of one of the pedicle screw, the locking cap and a fixation rod.
3. The system of claim 1, wherein the anti-torque device and torque-generating body cooperate to create a generally balanced reaction between a locking torque TL generated by the torque-generating body and an opposite reaction torque TR generated by the anti-torque device.
4. The system of claim 3, wherein the torque TL generated by the drive shaft of the torque-generating body is provided to one of the locking cap and the pedicle screw, and the opposite reaction torque TR generated by the anti-torque device is provided to one of the locking cap, the pedicle screw and a fixation rod.
5. The system of claim 1, wherein the torque-generating body is one of a motorized power tool, a pressurized fluid or a hand-actuated screwdriver.
6. The system of claim 1, wherein the anti-torque device is removably attached to the torque-generating body.
7. The system of claim 1, wherein the proximal end of the anti-torque device may selectively engage at least a portion of one or more generally unique distal portions of the torque-generating body.
8. The system of claim 7, wherein the proximal end of anti-torque device frictionally engages the distal portion of the anti-torque device.
9. The system of claim 7, wherein a projection of the proximal end of anti-torque device engages a groove of the distal portion of the anti-torque device.
10. The system of claim 1, wherein the anti-torque device further comprises a torque limiting mechanism that is connected to one of the torque-generating body.
11. The system of claim 10, further comprising a gearbox that includes a first spur gear and a second spur gear, wherein the first spur gear engages the second spur gear, and wherein the second spur gear receives the drive shaft.
12. The system of claim 11, wherein a gear ratio of the gearbox is between 2-to-1 and 10-to-1.
13. The system of claim 11, wherein the gearbox increases the input torque applied by the torque-generating body.
14. The system of claim 11, wherein the distal end of torque-generating body engages a notched shaft that is connected to a first gear, wherein the first gear drives the first spur gear.
15. The system of claim 1, wherein the anti-torque device comprises radially spaced-apart archways that extend radially inwardly from the distal end of the anti-torque device.
16. The system of claim 15, wherein a portion of one of the archways engages at least a portion of a fixation rod to maintain the distal end of the anti-torque device stationary.
17. The system of claim 1, wherein the torque-generating body is connected to a worm gear by a shaft, and wherein rotation of the torque-generating body rotates the worm gear to turn the drive shaft.
18. The system of claim 1, wherein the drive shaft comprises an outer sleeve that encloses a spring, wherein a distal portion of the outer sleeve is slidable along an axis of the drive shaft and is supported by the spring, and wherein the distal portion of the outer sleeve is rotationally engaged with the drive shaft.
19. The system of claim 1, wherein a proximal end of the anti-torque device slidably engages the distal end of the torque-generating body.
20. (canceled)
21. An anti-torque device for spinal surgery comprising:
- an elongated and generally hollow member defining a longitudinal axis, the member having a proximal end and an opposing distal end,
- wherein the proximal end is fixed from rotating relative to a portion of a torque-generating body, and
- wherein the distal end is fixed from rotating relative to at least a portion of one of a pedicle screw, a locking cap and a fixation rod.
22. The device of claim 21, further comprising:
- a drive shaft rotatably driven by the torque-generating body, a proximal end of the drive shaft being operatively engaged to the distal end of the torque-generating body and an opposing distal end of the drive shaft engaging at least a portion of one of the locking cap and the pedicle screw.
23. The device of claim 22, wherein the anti-torque device and torque-generating body cooperate to create a generally balanced reaction between a locking torque TL and an opposite reaction torque TR, and wherein the torque TL generated by the drive shaft of the torque-generating body is provided to one of the treaded cap and the pedicle screw, and the opposite reaction torque TR generated by the anti-torque device is provided to one of the treaded cap, the pedicle screw and the fixation rod.
24. The device of claim 21, wherein the anti-torque device is removably attached to the torque-generating body.
25. The device of claim 24, wherein a proximal end of the anti-torque device slidably engages the distal end of the torque-generating body.
26. The device of claim 25, wherein the proximal end of the anti-torque device has a keyed interface that engages a receiving face of an end member at the distal end of the torque-generating body.
27. The device of claim 21, wherein the anti-torque device further comprises a torque limiting mechanism that is connected to the a torque-generating body and to a gearbox, wherein the gearbox has a first spur gear that engages a second spur gear, and wherein the second spur gear receives a drive shaft that engages at least a portion of one of the locking cap and pedicle screw.
28. The device of claim 27, wherein rotation of the gearbox by the torque limiting mechanism rotates the drive shaft and increases the torque applied by the torque-generating body.
29. The device of claim 21, wherein the anti-torque device comprises radially spaced-apart archways that engage at least a portion of the fixation rod to maintain the distal end of the anti-torque device stationary.
30. A method of tightening a locking cap onto a pedicle screw during spine surgery, the method comprising:
- providing a torque-generating body having a drive shaft rotatably attached thereto;
- engaging at least a portion of a drive shaft with a locking cap;
- rotatably fixedly attaching a first end of an anti-torque device to at least a portion of the torque-generating body;
- rotatably fixedly attaching a second end of the anti-torque device to at least a portion of one of a pedicle screw, the locking cap and a fixation rod; and
- rotating the drive shaft to apply a locking torque to one of the locking cap and pedicle screw, thereby generating an equal and opposite reaction torque to one of the pedicle screw, the locking cap and the fixation rod.
31. The method of claim 30, further comprising:
- rotating the torque-generating body to create a generally balanced reaction between a locking torque TL generated by rotation of the torque-generating body and a generally equal and opposite reaction torque TR generated by the anti-torque device.
32. The method of claim 30, further comprising fixing a proximal end of the anti-torque device from rotating relative to at least a portion of the torque-generating body so as to not rotate with the drive shaft.
33. The method of claim 32, wherein fixing the proximal end of the anti-torque device comprises slidably engaging the proximal end of the anti-torque device with the distal end of the torque-generating body.
34. The method of claim 33, wherein the anti-torque device has a keyed interface that engages a receiving face of an end member at the distal end of the torque-generating body.
35. The method of claim 30, further providing a gearbox to increase the input torque provided by the torque-generating body applied to the drive shaft.
36. The method of claim 30, further comprising:
- providing radially spaced-apart archways at the second end of the anti-torque device; and
- engaging at least a portion of the fixation rod with the archways to maintain the anti-torque device stationary.
37. A surgical device, comprising:
- a torque-generating body having a proximal end and an opposing distal end;
- a gearbox that receives an input torque from the torque-generating body and provides an increased output torque to a drive shaft, a proximal end of the drive shaft being operatively engaged to the gearbox and a opposing distal end of the drive shaft engaging at least a portion of one of a locking cap and a pedicle screw; and
- an anti-torque device comprised of an elongated and generally hollow member defining a longitudinal axis, the member having a proximal end and an opposing distal end, the proximal end of the anti-torque device being slidably engaged to a housing of the gearbox and fixed from rotating relative to at least a portion of the torque-generating body.
38. The device of claim 37, wherein the anti-torque device and torque-generating body cooperate to create a generally balanced reaction between a locking torque TL and a generally equal and opposite reaction torque TR generated by the anti-torque device.
39. The device of claim 38, wherein the torque TL generated by the drive shaft of the torque-generating body is on one of the treaded cap and the pedicle screw, and the opposite reaction torque TR generated by the anti-torque device is on one of the treaded cap, the pedicle screw and a fixation rod.
40. The device of claim 37, wherein the proximal end of the anti-torque device is rotatably fixedly attached to and fixed from rotating relative to at least a portion of the torque-generating body so as to not rotate with the drive shaft.
41. The device of claim 37, wherein the anti-torque device further comprises a torque limiting mechanism that is connected to the a torque-generating body and to a first spur gear, and wherein the first spur gear engages a second spur gear that receives the drive shaft.
42. The device of claim 41, wherein the distal end of torque-generating body engages a notched shaft that is connected to a first gear, wherein the first gear drives the first spur gear.
43. The device of claim 37, wherein a gear ratio of the gearbox is between 2-to-1 and 10-to-1.
44. The device of claim 43, wherein the gearbox increases the input torque applied by the torque-generating body.
45. The device of claim 37, wherein the proximal end of the anti-torque device has a keyed interface that engages a receiving face of an end member at the distal end of the torque-generating body.
Type: Application
Filed: Oct 8, 2010
Publication Date: Apr 16, 2015
Applicant: SYNTHES USA, LLA (West Chester, PA)
Inventors: Jason Yim (San Francisco, CA), Dennis Chien (West Chester, PA), Barclay Davis (Glenmoore, PA), David Rathbun (West Chester, PA), Josef Gabelberger (West Chester, PA), Zoher S. Bootwala (Wilmington, DE), Scott Larsen (Devon, PA)
Application Number: 12/901,473
International Classification: A61B 17/70 (20060101); A61B 17/56 (20060101);