Internal Breakaway Set Screws and Drivers

Abstract

A method for engaging a set screw to an implant is provided. The method includes a surgical instrument. The surgical instrument may include a shaft having an elongated rigid structure, and a driver head positioned on a distal end of the surgical instrument. The driver head may include at least one groove or at least one protrusion extending in a longitudinal direction of the surgical instrument, and a pin at least partially positioned within the driver head. The pin may be configured to expand and retract from the driver head in a transverse direction.

Description

Background Art

[0001] Some surgeons may prefer to use a break-off set screw when fixing the rod to the collar of a spinal implant. A break-off set screw may be preferred, for example, to avoid insufficient and excessive torque of the set screw, loosening of the set screw, breakage of the set screw, or fracture of the screw or vertebra. The break-off set screw may be, for example, an external hexagonal break-off set screw. An example of a multiaxial screw comprising a break-off screw is described in U.S. Pat. No. 5,797,911, which is incorporated herein by reference in its entirety. However, in some cases, due to geometric interference problems, an external hexagonal break-off set screw cannot be used. In order to accommodate interference problems, a set screw with an internal drive feature may be used, such as a hexagonal groove or a hexagonal convex (hexalobe shaped) groove in the far end of the set screw. However, when the break-off head with an internal drive feature is separated from its set screw, the internal drive feature prevents the separated break-off head from being stacked on the nail magazine (magazine) of a break-off driver (breakoff driver). Furthermore, where multiple types of screws are used in a single construction, it can be cumbersome to repeatedly switch breakaway drivers or breakaway driver bits to accommodate various sizes of set screws and internal driver features. Summary of the invention

[0002] The present disclosure relates generally to spinal stabilization systems, and more particularly to surgical instruments for use with spinal stabilization systems.

[0003] In one or more embodiments, the disclosed technology is directed to a surgical instrument comprising a shaft having an elongated rigid structure and a driver head positioned at a distal end of the surgical instrument. In one or more cases, the driver head may include at least one groove or at least one protrusion extending in a longitudinal direction of the surgical instrument, and a pin at least partially positioned within the driver head. In one or more cases, the pin may be configured to extend and retract from the driver head in a transverse direction.

[0004] In one or more embodiments, the disclosed technology relates to a system for engaging a set screw to an implant. In one or more cases, the system may include a set screw comprising a breakaway head and a threaded portion coupled together via a breakaway region. In one or more cases, the breakaway head may include at least one interlocking portion. In one or more cases, the system may include a surgical instrument. In one or more cases, the surgical instrument may include a shaft having an elongated rigid structure, and a driver head positioned at the distal end of the surgical instrument. In one or more cases, the driver head may include at least one interlocking portion extending in the longitudinal direction of the surgical instrument and a pin at least partially positioned within the driver head. In one or more cases, the at least one interlocking portion of the driver head may be configured to interlock with the at least one interlocking portion of the breakaway head. In one or more cases, the pin may be configured to expand and retract from the driver head in a transverse direction.

[0005] The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of exemplary embodiments of the invention, as illustrated in the accompanying drawings in which like reference numerals generally represent like parts of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The following drawings illustrate specific embodiments of the present disclosure and therefore do not limit the scope of the present disclosure. The drawings are not drawn to scale and are intended to be used in conjunction with the explanations in the following detailed description.

[0007] Figure 1A is a side view showing an embodiment of a break-away screwdriver. Figure 1B An enlarged view of an embodiment of a magazine retaining portion is shown.

[0008] Figure 2A is a side view showing an embodiment of a break-away screwdriver. Figure 2B An enlarged view of an embodiment of a break-away driver's distal end is shown.

[0009] Figure 3A is an isometric view of an embodiment of a universal set screw. Figure 3B is another isometric view of an embodiment of a universal set screw.

[0010] Figure 4A is a cross-sectional side view of an embodiment of a break-away driver inserted into a universal set screw. Figure 4B is along Figure 4A A cross-sectional top view of an embodiment of a break-away screwdriver inserted into a universal set screw, taken along line AA in FIG.

[0011] Figure 5A, 5B , 5C and 5D show examples of universal fixation screws that engage various implants.

[0012] Figure 6 is a perspective view of an embodiment of a break-away screwdriver adapter.

[0013] Figure 7 is a perspective view of another embodiment of a break-away screwdriver. DETAILED DESCRIPTION

[0014] The following discussion omits or only briefly describes certain conventional features associated with spinal stabilization systems that are apparent to those skilled in the art. It should be noted that various embodiments are described in detail with reference to the accompanying drawings, wherein similar reference numerals represent similar parts and components throughout the several views. Reference to various embodiments does not limit the scope of the appended claims. In addition, any examples set forth in this specification are intended to be non-limiting and set forth only some of the many possible embodiments for the appended claims. In addition, the specific features described herein may be used in combination with other described features in each of the various possible combinations and arrangements.

[0015] Unless otherwise specifically defined herein, all terms should be given their broadest possible interpretation, including the meaning implicit from the specification and the meaning understood by those skilled in the art and / or as defined in dictionaries, papers, etc. It must also be noted that, unless otherwise indicated, the singular forms "a", "an", and "the" used in the specification and the appended claims include plural referents, and the terms "comprises" and / or "comprising" when used in this specification specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0016] Embodiments of the present disclosure relate generally to, for example, spinal stabilization systems, and more particularly to surgical instruments for spinal stabilization systems. Embodiments of apparatus and methods are described below with reference to the drawings.

[0017] It should be understood that the various aspects disclosed herein may be combined in combinations different from those specifically presented in the specification and drawings. It should also be understood that, depending on the instance, certain actions or events of any process or method described herein may be performed in a different order, may be added, combined, or omitted entirely (e.g., all described actions or events may not be necessary to perform the technique).

[0018] Figure 1Ais a side view showing an embodiment of a break-away driver 100 . Figure 1B An enlarged view of an embodiment of the magazine retaining portion 106 is shown. Figure 2A is a side view showing an embodiment of a break-away driver 100 . Figure 2B An enlarged view of an embodiment of the distal end of the break-away driver 100 is shown. Figure 3A is an isometric view of an embodiment of a break-away set screw, such as universal break-away set screw 110 (“set screw 110 ”). Figure 3B is another isometric view of an embodiment of a set screw 110 .

[0019] Figure 4A is a cross-sectional side view of an embodiment of a break-away driver 100 inserted into a set screw 110 (“set screw 110 ”). Figure 4B is along Figure 4A A cross-sectional top view of an embodiment of a break-away screwdriver 100 inserted into a set screw 110, taken along line AA in FIG. Figure 3A , 3B Examples of fixation screws 110 engaged with various implants are shown.

[0020] In one or more embodiments, the breakaway screwdriver 100 includes an optional handle 102; a screwdriver head, such as a magazine holding portion 106; and a shaft 104. The shaft 104 can be an elongated rigid member configured to connect the handle 102 and the magazine holding portion 106. The handle 102 and the magazine holding portion 106 can be disposed at opposite ends of the shaft 104. In one or more cases, the shaft 104 can have a linear shape. In one or more other cases, the shaft 104 can have a curved shape. In one or more cases, the handle 102 can be fixed to the shaft 104. In one or more other cases, the handle 102 can be removably attached to the shaft 104. The handle 102 can provide a grip for the user to manipulate the magazine holding portion 106.

[0021] The shaft 104 and the magazine retaining portion 106 may be individually or collectively made of materials such as stainless steel alloys, commercially pure titanium, titanium alloys, grade 5 titanium, superelastic titanium alloys, cobalt-chromium alloys, stainless steel alloys, and combinations thereof.

[0022] In one or more embodiments, the magazine holding portion 106 can be an elongated rigid member disposed on the distal end of the break-away screwdriver 100. The magazine holding portion 106 can include a pin 206 configured to be deployed and / or retracted from within the magazine holding portion 106, such as Figure 2A and 2B In one or more cases, the pin 206 can be configured to be perpendicular to the longitudinal direction L of the magazine holding portion 106. 1In one or more other cases, the pin 206 can be configured to extend and / or retract in the lateral direction L of the magazine holding portion 106. 2 Expand and / or retract.

[0023] In one or more embodiments, the pin 206 can be spring loaded. For example, the elongated member 230 of the pin 206 can extend through the partition wall 228, wherein the first end 224 of the pin 206 is located on one side of the partition wall 228 and the second end 226 of the pin 206 is located on the opposite side of the partition wall 228. In one or more embodiments, the elongated member 230 can be a cylindrical rigid member and its diameter can be smaller than the diameter of the second end 226. The portion of the first end 224 of the pin 206 can include a force F generated by the spring 208 to prevent the pin 206 from being moved. 1 The stop member 210 of the magazine holding portion 106 is completely withdrawn in the direction of the second end 226 of the pin 206. The second end 226 of the pin 206 may include a hemispherical shape 226a on the distal portion of the second end 226 and a flat surface 226b on the proximal portion of the second end 226. The flat surface 226b may be located on both sides of the elongated member 230. The pin 206 may be inserted through the spring 208, wherein one end of the spring 208 is configured to contact the partition wall 228 and the opposite end of the spring 208 is configured to contact the flat surface 226b of the second end 226. The spring 208 may be configured to apply a force F to the flat surface 226b 1 To move a portion of the second end 226 beyond the outer surface 232 of the magazine holding portion 106 .

[0024] In one or more embodiments, the set screw 110 includes a threaded portion 110a and a breakaway head 110b coupled to each other via a breakaway region 202. The threaded portion 110a can have external threads around an outer surface 232 of the set screw 110. The threaded portion 110a can be configured to attach to a collar, such as collars 306, 308, 310, and / or 312, and capture the longitudinal member 304. The set screw 110 can be sized to fit within the collar.

[0025] The breakaway zone 202 may extend circumferentially around the outer surface 232 of the set screw 110. In one or more cases, the recessed area 204 may be formed on a side of the breakaway head 110b opposite the breakaway zone 202. In one or more cases, the recessed area 204 may extend circumferentially around the inner surface 222 of the set screw 110. In one or more other cases, the recessed area 204 may extend circumferentially and intermittently around the inner surface 222 of the set screw 110. The recessed area 204 may be large enough to receive a portion of the second end 226 of the set screw 110. For example, the recessed area 204 may be configured to receive the hemispherical portion 226a of the second end 226. In one or more cases, the surface 238 of the recessed area 204 may be formed in a curved shape. The curved shape may be configured to correspond to the hemispherical portion 226a of the second end 226. In one or more other cases, the surface 238 of the recessed area 204 may be formed in a semi-trapezoidal shape.

[0026] In one or more cases, at least a portion of the second end 226 of the pin 206 can be configured to extend beyond the outer surface 232 of the magazine holding portion 106 in the deployed state. In the retracted state, the pin 206 can be housed within the magazine holding portion 106. In one or more cases, the pin 206 can be aligned to protrude through a portion of the recess 108 of the magazine holding portion 106. In one or more other cases, the pin 206 can be aligned to protrude through a portion of the outer surface 232 of the magazine holding portion 106 that does not include the recess 108.

[0027] In one or more embodiments, the diameter of the magazine holding portion 106 can be large enough to fit tightly within the opening 234 of the breakaway head 110b of the set screw 110. For example, the diameter of the magazine holding portion 106 can be large enough so that a portion of the distal end of the magazine holding portion 106 can fit within at least a portion of the breakaway head 110b. The outer circumferential surface 232 of the magazine holding portion 106 can be corrugated or formed as a hexagonal convex shape so that a plurality of grooves, such as the grooves 108, can be circumferentially disposed around the outer surface 232 of the magazine holding portion 106. The grooves 108 can be arranged in the longitudinal direction L of the magazine holding portion 106. 1 The groove 108 can be configured to align the disconnected screwdriver 100 in the groove 236 of the fixing screw 110. The groove 108 can be used as a guide for sliding the disconnected disconnected head along the nail magazine holding portion 106. When viewed from the top view of the nail magazine holding portion 106, the groove 108 can be formed in the nail magazine holding portion 106 in various shapes, such as an arc or curved shape, a square shape, a triangular shape, etc. In one or more cases, adjacent grooves 108 can be separated by a protrusion. In one or more other cases, the nail magazine holding portion 106 only includes one groove.

[0028] The inner surface 222 of the break-away head 110b may be corrugated or in a hexagonal convex shape so that the plurality of protrusions 236 are positioned in the longitudinal direction L of the break-away head 110b. 2 The inner surface 222 of the disconnected head 110b is arranged circumferentially. In one or more cases, adjacent protrusions 236 may be separated by grooves. In one or more cases, the plurality of protrusions 236 on the inner surface 222 of the disconnected head 110b may be configured to interlock with the plurality of grooves 108 arranged around the magazine holding portion 106. In addition, the plurality of grooves formed by the protrusions 236 of the disconnected head 110b may be configured to interlock with the plurality of protrusions formed by the grooves 108 of the magazine holding portion 106. By interlocking the plurality of protrusions 236 of the disconnected head 110b with the magazine holding portion 106, the fixing screw 110 may be prevented from rotating in a clockwise or counterclockwise manner around the magazine holding portion 106. In one or more cases, the interlocking portion of the disconnected head may be the protrusions 236, and the interlocking portion of the magazine holding portion 106 may be the grooves 108. In one or more cases, the interlocking portion of the break-away head can be a groove and the interlocking portion of the magazine retaining portion 106 can be a protrusion.

[0029] In one or more embodiments, the opening 234 of the disconnect head 110 may be larger than the opening 242 of the threaded portion 110a. In one or more cases, the inner surface 240 of the threaded portion 110a may be corrugated or have a hexagonal convex shape so that the plurality of protrusions 244 are positioned in the longitudinal direction L of the threaded portion 110a. 2 The screwdriver 242 of the threaded portion 110a is disposed circumferentially on and around the inner surface 240 of the breakaway head 110a. In one or more cases, after the breakaway head 110b is broken away from the threaded portion 110a, another screwdriver can be inserted into the opening 242 of the threaded portion 110a to tighten or loosen the set screw 110.

[0030] In one or more embodiments, the magazine holding portion 106 can be configured to disconnect the disconnect head 110b from the threaded portion 110a of the set screw 110. In one or more examples, the set screw 110 can be fixed into an implant, such as a uniaxial screw (UNI) 318, a multiaxial screw (MAS) 320, a reduction head multiaxial screw (RMAS) 322, or an extended tab MAS 324, such as Figure 3A-3BAs shown. The implant can be fixed to a bone structure, such as a vertebra. In order to disconnect the breakaway head 110b from the threaded portion 110a of the set screw 110, the user inserts the magazine holding portion 106 into the opening 234 of the breakaway head 110b so that the inner surface 222 of the breakaway head 110b interlocks with the outer surface 232 of the magazine holding portion 106, as described above. After the breakaway head 110b is interlocked with the magazine holding portion 106 in the circumferential direction, the user can rotate the handle 102 in a clockwise or counterclockwise manner, thereby rotating the shaft 104 and the magazine holding portion 106. Under a certain amount of torque generated by rotating the breakaway driver 100 in the set screw 110, the breakaway head 110b can be disconnected from the threaded portion 110a of the set screw 110. In one or more embodiments, the break-away head 110b can be broken away from the threaded portion 110a at a torque ranging from about 8 Newton meters (Nm) to about 12 Nm.

[0031] In one or more embodiments, the magazine holding portion 106 can be configured to hold one or more disconnected disconnected heads, such as broken heads 112, 114, 116, 118, 120, 122, and 124. In one or more cases, the size of the magazine holding portion 106 can be designed to hold one or more disconnected disconnected heads. For example, the magazine holding portion 106 can be long enough to hold at least six disconnected disconnected heads. In another example, the size of the magazine holding portion 106 can be designed to hold eight disconnected disconnected heads. When each disconnected head is disconnected from the set screw, the disconnected heads can be stacked on each other so that the first disconnected head is positioned at the top of the stack, followed by the next first disconnected head.

[0032] As the magazine holding portion 106 is inserted into the opening 234 of the fixing screw 110, the groove 108 of the magazine holding portion 106 is aligned with the groove 236 of the disconnected head 110b, and the spring 208 is configured to be in an expanded state. As the magazine holding portion 106 is inserted into the opening 234 of the fixing screw 110, the curved bottom 216 of the second end 226 contacts the tapered distal end 220 of the disconnected head 110b. The tapered distal end 220 can taper downward toward the center of the disconnected head 110b. As the magazine holding portion 106 is inserted deeper into the disconnected head 110b, the tapered distal end 220 and / or the inner surface 222 can force the pin 206 to retract into the magazine holding portion 106, thereby compressing the spring 208. When the pin 206 reaches the recessed area 204, the spring 208 forces the pin 206 to enter the expanded state, wherein the pin 206 enters the recessed area 204.

[0033] In the case where the break-away head 110b is broken away from the threaded portion 110a, the curved upper surface 218 of the second end 226 protrudes far enough to prevent the separated break-away head 110b from sliding out of the magazine holding portion 106. In the case where the second break-away head is separated from the second set screw, the separated second break-away head forces the first separated break-away head 110b to slide upward along the magazine holding portion 106. As each separated break-away head is added to the magazine holding portion 106, the separated break-away heads can be stacked on top of each other.

[0034] Figure 6 is a perspective view of an embodiment of a break-away screwdriver adapter 200. In one or more embodiments, the break-away screwdriver adapter 200 is an elongated member that includes a magazine retaining portion 106 disposed on one end of the break-away screwdriver adapter 200 and a screw receiver 202 disposed on an opposite end of the break-away screwdriver adapter 200. The magazine retaining portion 106 of the break-away screwdriver adapter 200 includes one or more features that are the same or similar to the magazine retaining portion 106 of the break-away screwdriver 100. Therefore, the description of such features will not be repeated. In one or more cases, the screw receiver 202 is configured into an external shape to achieve a secure, non-slip engagement with a multi-bit driver. For example, the screw receiver 202 may be formed as 1 / 4 inch hexagonal drill bit, wherein the insertion end 204 is inserted into the drill receiving portion of the multi-bit driver. The driver receiver 202 can be removably coupled to the multi-bit driver so that other break-away driver adapters configured to engage setscrews of different shapes can be inserted into the multi-bit driver.

[0035] Figure 7 is a perspective view of another embodiment of a break-away screwdriver 300. In one or more embodiments, the break-away screwdriver 300 includes a magazine retaining portion 106 disposed on one end of the break-away screwdriver 300 and an optional handle 102 disposed on an opposite end of the break-away screwdriver 300. The magazine retaining portion 106 and the handle 102 of the break-away screwdriver 300 include one or more features that are the same or similar to the magazine retaining portion 106 and the handle 102 of the break-away screwdriver 100. Therefore, the description of such features will not be repeated.

[0036] In one or more cases, the break-away screwdriver 300 includes a shaft 104. The shaft 304 can be an elongated rigid member configured to connect the handle 102 and the magazine holding portion 106. The handle 102 and the magazine holding portion 106 can be disposed at opposite ends of the shaft 304. In one or more cases, the shaft 304 can have a linear shape. In one or more other cases, the shaft 304 can have a curved shape.

[0037] Axis 304 includes a first shaft portion 306a that is removably connected to a second shaft portion 306b. In one or more cases, the nail magazine holding portion 106 can be connected to the first shaft portion 306a. Axis 304 and nail magazine holding portion 106 can be made of materials such as stainless steel alloy, commercial pure titanium, titanium alloy, grade 5 titanium, superelastic titanium alloy, cobalt chromium alloy, stainless steel alloy and combinations thereof, individually or jointly. In one or more cases, handle 102 can be fixed to the second shaft portion 306b. In one or more other cases, handle 102 can be attached to the second shaft portion 306b in a removable manner. In one or more embodiments, the first shaft portion 306a and nail magazine holding portion 106 can be manufactured together, and the second shaft portion 306b can be manufactured separately from the first shaft portion 306a and the nail magazine holding portion 106. Subsequently, the first shaft portion 306a and the second shaft portion 306b can be connected together, thereby forming the shaft 304. In one or more cases, the first shaft portion 306a includes a protrusion 302a configured to fit within the receiving portion 302b of the second shaft portion 306b. In some cases, the protrusion 302a can have a threaded end configured to mate with the threaded end of the receiving portion 302b. In some other cases, the protrusion 302a can snap fit within the receiving portion 302b. In one or more other cases, the second shaft portion 306b includes a protrusion 302a configured to fit within the receiving portion 302b of the first shaft portion 306a.

[0038] As used herein, the term "about" with respect to a numerical value means plus or minus 10% of the numerical value of the number being used.

[0039] The above-mentioned features and functions and alternatives can be combined into many other different systems or applications. Those skilled in the art may make various alternatives, modifications, changes or improvements, each of which is also intended to be covered by the disclosed embodiments.

Claims

1. A surgical instrument, include: A shaft with a slender and rigid structure, a fixing screw including a threaded portion and a breakaway head connected to each other via a breakaway region, a recessed area being formed on a side of the breakaway head opposite to the breakaway region; as well as a screwdriver head positioned at the distal end of the surgical instrument, Wherein the screwdriver head comprises: a nail magazine holding portion configured to hold a plurality of disconnected breakaway heads, at least one groove or at least one protrusion extending in the longitudinal direction along the magazine holding portion; a spring and a pin at least partially positioned within the driver head, the spring and the pin being positioned between the distal end of the surgical instrument and the magazine holding portion, and The pin includes a first end and a second end, the first end of the pin includes a stop member, the second end of the pin includes a hemispherical shape on a distal portion and a flat surface on a proximal portion, the pin is inserted through the spring, the spring is configured to apply a force to the flat surface to move a portion of the second end of the pin beyond the outer surface of the magazine holding portion, the recessed area is configured to receive the hemispherical shape of the second end of the pin, wherein the pin is configured to expand and retract from the driver head in a lateral direction, and the pin is constructed so that when the break-away head of the fixing screw is broken away from the threaded portion, the second end protrudes far enough to prevent the separated break-away head from sliding out of the magazine holding portion.

2. The surgical instrument of claim 1, further comprising a handle positioned on an end of the surgical instrument opposite the driver head.

3. The surgical instrument of claim 1, wherein the at least one groove is configured to interlock with at least one groove positioned on an inner surface of an opening of a set screw. 4 . The surgical instrument of claim 1 , wherein the at least one protrusion is configured to interlock with at least one groove positioned on an inner surface of an opening of the set screw.

5. The surgical instrument of claim 1, wherein a distal portion of the pin positioned in the deployed state extends beyond an outer surface of the driver head.

6. The surgical instrument of claim 5, wherein the distal portion of the pin positioned in the deployed state is configured to prevent at least one broken-away head of a break-away set screw from sliding off the driver head.

7. A system for engaging a fixation screw to an implant, the system include: a set screw including a breakaway head and a threaded portion coupled together via a breakaway zone, a recessed area formed on a side of the breakaway head opposite to the breakaway zone; wherein the break-away head comprises at least one interlocking portion; and Surgical instruments including the following: A shaft having a slender rigid structure, and a screwdriver head positioned at the distal end of the surgical instrument, Wherein the screwdriver head comprises: a nail magazine holding portion configured to hold a distance between a plurality of disconnected breakaway heads, at least one groove or at least one protrusion extending in the longitudinal direction along the magazine holding portion; at least one interlocking portion extending in the longitudinal direction of the surgical instrument and a spring and a pin at least partially positioned within the driver head, the spring and the pin being positioned between the distal end of the surgical instrument and the magazine holding portion, and wherein the pin comprises a first end and a second end, the first end of the pin comprising a stop member, the second end of the pin comprising a hemispherical shape on a distal portion and a flat surface on a proximal portion, the pin being inserted through the spring, the spring being configured to apply a force to the flat surface to move a portion of the second end of the pin beyond an outer surface of the magazine holding portion, The recessed area is configured to receive the hemispherical shape of the second end of the pin, wherein the pin is configured so that when the breakaway head of the set screw is broken away from the threaded portion, the second end protrudes far enough to prevent the separated breakaway head from sliding out of the magazine holding portion, wherein the at least one interlocking portion of the driver head is configured to interlock with the at least one interlocking portion of the break-away head, and Wherein the pin is configured to be extended and retracted from the driver head in a lateral direction.

8. The system of claim 7, wherein the surgical instrument further comprises a handle positioned on an end of the surgical instrument opposite the driver head.

9. The system of claim 7, wherein the at least one interlocking portion of the break-away head comprises a groove, and wherein the at least one interlocking portion of the driver head comprises a protrusion.

10. The system of claim 7, wherein the at least one interlocking portion of the break-away head comprises a protrusion, and wherein the at least one interlocking portion of the driver head comprises a groove.

11. The system according to claim 7, in, The driver head is configured to disconnect the break-away head from the threaded portion when rotated when the at least one interlocking portion of the driver head is interlocked with the at least one interlocking portion of the break-away head.

12. The system of claim 7, wherein the set screw further comprises a recessed area positioned on an inner surface of the set screw opposite the breakaway zone.

13. The system of claim 12, wherein the recessed area is formed in a shape complementary to a shape of a distal portion of the pin.

14. The system of claim 12, wherein the distal portion of the pin is configured to be inserted into the recessed region of the set screw.

15. The system of claim 14, wherein the distal portion of the pin positioned in the deployed state is configured to prevent the breakaway head disconnected from the set screw from sliding off the driver head.

16. The system of claim 12, wherein a distal portion of the pin positioned in the deployed state extends beyond an outer surface of the driver head, and wherein the distal portion of the pin is configured to be inserted into the recessed region of the set screw.

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