Universal pedicle screw removal device and related methods

A pedicle screw removal device comprises a rod having a first end and a second end opposite the first. A clamping member is located at the first end of the rod, and a handle is located at the second end. The clamping member is configured to remove a pedicle screw via clamping to a pedicle screw socket. To remove a pedicle screw, the rod is inserted into a pedicle screw socket until a screw engagement surface on the first end portion of the rod is met by a head of the pedicle screw. The clamping member is lowered to a desired position and clamped to the pedicle screw socket. Rotating the handle unscrews the pedicle screw while the screw engagement surface is pressing on the screw head.

FIELD OF THE INVENTION

The present invention relates to orthopedic devices, more particularly to pedicle screws, and more particularly to pedicle screw removal devices.

BACKGROUND OF THE INVENTION

Spinal pain can result from the wearing of vertebral joints over time. Surgery performed to reduce this spinal pain often involves a combination of polyaxial pedicle screws and rods to create a spinal fixation system. Often, a surgeon will use a certain tool to remove a certain type of pedicle screw. This increases the complexity and reduces the efficiency of a surgery. Various tools have been developed for pedicle screw removal, but their deficiencies suggest that further improvements can be realized.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention to provide an improved pedicle screw removal device and related methods. According to one embodiment of the invention, the pedicle screw removal device includes a rod having a first end and a second end opposite the first. A clamping member is located at the first end and a handle at the second end. The clamping member is configured to remove a pedicle screw by clamping to a pedicle screw socket.

According to another embodiment of the invention, a method of removing a pedicle screw using the pedicle screw removal device includes inserting the rod into a pedicle screw socket until a screw engagement surface on the first end of the rod is met by the head of the pedicle screw. The clamping member is lowered to a desired position and clamped to the pedicle screw socket. The handle is rotated to remove the pedicle screw while the screw engagement surface presses on the screw head.

These and other objects, aspects and advantages of the present invention will be better appreciated in view of the drawings and following detailed description of preferred embodiments.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

According to an embodiment of the present invention, and referring toFIGS. 1-3, the pedicle screw removal device10includes a rod12, a clamping member14located at a first end16of the rod12and a handle18on a second end20of the rod12opposite the clamping member14. The pedicle screw removal device10clamps to a pedicle screw socket26to unscrew and remove a pedicle screw22.

The rod12is elongated, and a substantially circular or square cross-section is preferred, though other cross-sections will be possible. A screw engagement surface24is integrally formed at the first end16of the rod12, stabilizing the polyaxial pedicle screw22once the rod12is inserted into a pedicle screw socket26and pushed against the head of the pedicle screw22. The rod12further includes an integrated gear track28at the first end portion of the rod12, allowing the clamping member14to be engaged with the rod12. Metal is the preferred material for rod12, but any suitably durable material can also be used. The screw engagement surface24has a preferred diameter of 3-10 mm.

In one embodiment of the present invention, the clamping member14includes a sleeve30and a lever32. The sleeve30is open-ended and defines a rod guide area34, allowing the rod12to be inserted therethrough. The dimensions are such that the rod12is closely accommodated in the rod guide area34. The sleeve30surrounds and moves along the rod12. It will advantageous for the design and configuration of sleeve30to be such that it is split into two sections, each clamping to the inner or outer surface of the pedicle screw socket26.

The lever32is configured at the top end of the sleeve30, providing locking and clamping mechanisms for the clamping member14. When the lever32is pulled away from the sleeve30, the lever32disengages from the integrated gear track28of the rod12and unlock a sleeve lock (not shown), making the clamping member unsplittable. Thus, the clamping member14can move along (e.g., slide over, screw along, etc.) the rod12. When the lever32is pushed toward the sleeve30, the lever32can engage the gear track28, stabilize the sleeve30, and engage the sleeve lock (not shown) such that each half of the sleeve30is tightly clamped to the outer surface of the pedicle screw socket26, as shown inFIG. 2.

Referring toFIG. 3, in an alternate embodiment of the present invention, the clamping member14can be designed and configured to clamp the pedicle screw22from an inner surface of the pedicle screw socket26. A clamping surface36is formed and extends outwardly from the bottom end of a sleeve wall38. When the lever32is pulled away the clamping member14, the clamping member14can be lowered into the pedicle screw socket26. The lever32can then pushed toward the sleeve30such that it can split into two half sections, each pushing against the inner surface of the pedicle screw socket26. Other adjustment mechanisms, collars or the like could be used for releasable clamping of the sleeve30to the inner or outer surface of the socket26.

In the embodiment depicted inFIGS. 1-3, the handle18comprises an ergonomically-shaped knob, though other shapes are possible, for example, a T-shaped knob. The size of the knob will be such that it will fit comfortably in a user's hand.

Referring toFIGS. 4-15, according to anther embodiment of the invention, the rod12A has screw threads designed to connect to the clamp member14A on the first end and the handle18A on the second end by the respective matching conforming thread.

The clamp member14A comprises the sleeve30A, the lever32A and a pair of clamping arms42A. The sleeve30A is dimensioned so as to conform to the rod guide area34A and thus closely accommodate the rod12A and the lever32A. The sleeve30A and the lever32A can move (e.g., screw) along the rod12A in the rod guide area34. The pair of clamping arms42A is attached to the lever32A via a spring biased mechanism44A. In the depicted embodiment, the lever32A is wedge-shaped, wider at the upper side and tapering toward the bottom apex with an elongated protrusion24A formed extending from the apex. As such, the pair of clamping arms42A is forced to split outwardly along a plane to an extended position, generally transverse to the longitudinal axis of the rod12A, when the lever32A moves downwards, as shown inFIGS. 9 and 10. Likewise, the pair of clamping arms42A is withdrawn to a retracted position at least partially within the elongated protrusion24A when the lever32A moves upwards along the rod12A, as shown inFIGS. 11 and 12.

The pair of clamping arms42A, when in an extended position can clamp to the inner surface of the pedicle screw socket26A, as shown inFIG. 13. The bottom end of the pair of clamping arms42A has grooves46A that engages grooves of the thread of an inner surface of the pedicle screw socket26A. As such, when the pedicle screw22is unscrewed (seeFIG. 3for typical pedicle screw22and socket26arrangement), the grooves46A can push against grooves of the thread of an inner surface of the pedicle screw socket26A. In a preferred embodiment, the grooves46A are silver soldered with carbide for enhanced durability and longevity.

When the lever32A moves upward, the pair of clamping arms42A gradually moves inward from an extended position to a retracted position. The pair of arms42A will now be closed, enabling easy withdrawn from the screw socket26A, as shown inFIG. 14. The pair of clamping arms42A can now transit from the extended position to the retracted position. That is, when the handle18A is rotated clockwise, the screw head40is moved upward, pushing the lever32A upwards, the distance between the pair of clamping arms42A is reduced, enabling the pedicle removal device10A to be withdrawn from the screw socket26A.

Referring toFIG. 16, a method for removing a pedicle screw22using the pedicle screw removal device10is described. Before positioning the pedicle screw removal device10on the pedicle screw22, a pedicle screw cap is removed from a socket26. The rod of the previously implemented fixation system will also need to be removed from the socket26. At step1602, the rod12is inserted into the pedicle screw socket26until the screw engagement surface24of the rod12is met by the head40of the screw22. At step1604, the clamping member14is lowered to a desired position with the lever32moved upward along the rod12. At step1606, once the clamping member14reaches to the desired position, the lever32is moved downward along the rod12, allowing the pair of clamping arms42to clamp to the inner surface of the pedicle screw socket26. The bottom point of the lever32is pressed against the head40of the pedicle screw22, firmly engaging it. At step1608, the pedicle screw removal device10is then rotated with the handle18, unscrewing and removing the pedicle screw22. The pedicle screw removal device10can be used to remove any type or size of polyaxial pedicle screw.

From the foregoing, it will be appreciated that a pedicle screw removal device according to the present invention enables the easy removal of a polyaxial pedicle screw by effective locking of the pedicle screw against the socket and removing both as a single unit. Moreover, the device is readily adaptable to a wide range of pedicle screw sizes from a variety of manufacturers. The present invention thus eliminates the need for a surgeon to have a wide range of manufacturer-specific tools on hand to remove a pedicle screw. The invention will be particularly useful in cases where the manufacturer(s) of such screws are unknown until after surgery has commenced, if they can be identified then.

In general, the foregoing description is provided for exemplary and illustrative purposes; the present invention is not necessarily limited thereto. Rather, those skilled in the art will appreciate that additional modifications, as well as adaptations for particular circumstances, will fall within the scope of the invention as herein shown and described and of the claims appended hereto.