Set screw reducer for modular reduction screws

Systems, instruments, and methods for advancing a set screw in an object. The methods comprise: disposing a shank tip of a set screw reducer in a socket of the set screw; causing a sleeve integrated with the set screw reducer to slidingly engage a shank of the set screw reducer and move in a direction towards the shank tip; transferring torque from the set screw reducer to the set screw such that the set screw is advanced in a threaded hole of the object; and using the sleeve of the set screw reducer to substantially prevent splaying of at least one sidewall of the object while the torque is being transferred from the set screw reducer to the set screw.

BACKGROUND

Spinal disorders such as degenerative disc disease, disc herniation, osteoporosis, spondylolisthesis, stenosis, scoliosis and other curvature abnormalities, kyphosis, tumor, and fracture may result from factors including trauma, disease and degenerative conditions caused by injury and aging. Spinal disorders typically result in symptoms including pain, nerve damage, and partial or complete loss of mobility.

Non-surgical treatments, such as medication, rehabilitation, and exercise can be effective, however, may fail to relieve the symptoms associated with these disorders. Surgical treatment of these spinal disorders includes correction, fusion, fixation, discectomy, laminectomy, and/or implantable prosthetics. As part of these surgical treatments, spinal constructs, which include implants such as bone fasteners, connectors, plates, and vertebral rods are often used to provide stability to a treated region. These implants can redirect stresses away from a damaged or defective region while healing takes place to restore proper alignment and generally support the vertebral members. Surgical instruments are employed, for example, to engage the fasteners for attachment to two or more vertebral members. This disclosure describes improvements over these prior technologies.

SUMMARY

The present disclosure relates to implementing systems and methods for advancing a set screw in an object. The methods comprise: sliding a sleeve of a set screw reducer along an elongate length of a shank of the set screw reducer in a direction away from the shank's tip until the sleeve is in a position which decreases, reduces or eliminates the sleeve's interference with a coupling between the set screw reducer (or driver) and the set screw; disposing the shank's tip in a socket of the set screw; causing the sleeve to slidingly engage the shank of the set screw reducer and move in a direction towards the shank tip; transferring torque from the set screw reducer to the set screw such that the set screw is advanced in a threaded hole of the object (e.g., in response to a rotational force being applied to a handle of the set screw reducer); and using the sleeve of the set screw reducer to substantially prevent splaying of at least one sidewall of the object while the torque is being transferred from the set screw reducer to the set screw. The term “substantially” as used herein means the object's sidewall remains disposed within the sleeve and/or remains in contact with a sidewall of the sleeve.

In some scenarios, the sleeve, as part of splaying prevention, resists an outward bending of the at least one sidewall of the object throughout the advancement of the set screw in the object. A free end of the at least one sidewall of the object may be continuously disposed within a recess formed in the sleeve, while the set screw reducer is being used to advance the set screw in the object. The free end of the at least one sidewall of the object causes the sleeve to move along an elongate length of the shank in a direction away from the shank tip while the set screw is being advanced in the object.

In those or other scenarios, the methods may further comprise: receiving an end of an external instrument or tool in a socket formed in a handle of the set screw reducer; and using the external instrument or tool to cause rotation of the handle.

Additionally or alternatively, the methods comprise establishing a frictional engagement between the shank tip and the set screw. The frictional engagement may be established by resiliently biasing at least one engagement part of the set screw reducer into a detent or a groove formed in a sidewall of the socket of the set screw. The engagement part may include, but is not limited to, a ball bearing that is resiliently biased by a resilient member in a direction out and away from the shank tip.

The disclosure also relates to a surgical instrument (e.g., a set screw reducer or driver). The surgical instrument comprises: a shank having a shank tip sized and shaped to fit in a socket of a set screw; and a sleeve disposed on the shank such that the sleeve slidingly engages the shank to move at least in a first direction towards the shank tip. Torque is transferable from the shank to the set screw such that the set screw is advanced in a threaded hole of an object (e.g., in response to a rotational force being applied to a handle of the surgical instrument). The sleeve prevents splaying of at least one sidewall of the object while the torque is being transferred from the shank to the set screw.

The sleeve is also able to slide along an elongate length of the shank in a direction away from the shank tip until the sleeve is in a positon which substantially eliminates the sleeve's interference with a coupling between the surgical instrument and the set screw. The term “substantially” as used here means the sleeve is not blocking the coupling. As part of the splaying prevention, the sleeve resists an outward bending of the at least one sidewall of the object throughout the advancement of the set screw in the object. In this regard, it should be understood that a free end of the at least one sidewall of the object is continuously disposed within a recess formed in the sleeve, while the surgical instrument is being used to advance the set screw in the object. The free end of the at least one sidewall of the object causes the sleeve to move along an elongate length of the shank in a direction away from the shank tip while the set screw is being advanced in the object.

In some scenarios, the surgical instrument also comprises a handle having a socket to receive an end of an external instrument or tool that facilitates rotation of the handle during advancement of the set screw in the object. Additionally or alternatively, the surgical instrument comprises a frictional retention structure that establishes a frictional engagement between the shank tip and the set screw. The frictional engagement may be established by resiliently biasing at least one engagement part of the frictional retention structure into a detent or a groove formed in a sidewall of the socket of the set screw. The engagement part may include, but is not limited to, a ball bearing that is resiliently biased by a resilient member in a direction out and away from the shank tip.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts of the disclosure.

DETAILED DESCRIPTION

The following discussion omits or only briefly describes certain conventional features related to surgical systems for treating the spine, which are apparent to those skilled in the art. It is noted that various embodiments are described in detail with reference to the drawings, in which like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims appended hereto. Additionally, any examples set forth in this specification are intended to be non-limiting and merely set forth some of the many possible embodiments for the appended claims. Further, particular features described herein can be used in combination with other described features in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be given their broadest possible interpretation including meanings implied from the specification as well as meanings understood by those skilled in the art and/or as defined in dictionaries, treatises, etc. It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless otherwise specified, and that 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.

Embodiments of the present disclosure relate generally, for example, to medical devices and methods for treating musculoskeletal disorders, and more particularly, to surgical systems and methods for treating the spine. Embodiments of the devices, methods, and systems are described below with reference to the Figures.

FIGS. 1-3provide perspective views of a set screw reducer100. A cross-sectional view of the set screw reducer is provided inFIG. 4. As shown inFIGS. 1-4, the set screw reducer100comprises a shank102and a handle104. The handle104resides at a proximal end108of the shank102. The shank102and handle104may be integrally formed as one part (not shown), or alternatively be coupled to each other via a coupling means as shown inFIG. 4. The coupling means can include, but is not limited to, a weld, adhesive, and/or threads. The shank102and handle104are formed of stainless steel, titanium or other alloy which is resistant to corrosion. The handle104has a size and shape that allows an individual to easily grip and turn the same without discomfort. The handle104transfers torque from the individual to the shank102.

Notably, the handle104has a socket200formed therein as shown inFIG. 2andFIG. 4. The socket200is sized and shaped to receive an end of an external instrument or tool (e.g., a power attachment, or a manual wrench) that can facilitate the rotation of the shank102. The external instrument or tool may optionally be employed when it becomes difficult for the individual to apply torque to the set screw reducer100when driving a screw (e.g., such as screw600shown inFIGS. 6-7) into an object (e.g., a bone, an implant or a receiver during a medical procedure).

The external instrument or tool can include, but is not limited to, a power attachment with a hex bit, or a manual Allen wrench. Power attachments and Allen wrenches are well known in the art, and therefore will not be described here. For example, an illustrative Allen wrench is shown inFIG. 5. In the Allen wrench scenario, the socket200has a hexagonal shape and the Allen wrench500has a hexagonal head at each end502,504which can be inserted into the hexagonal shaped socket200of the set screw reducer100. A torque may be applied to the set screw reducer100by the Allen wrench500, whereby the set screw reducer is caused to rotate. The set screw reducer100transfers the torque to the set screw (e.g., set screw600ofFIGS. 6-7), whereby the set screw is caused to rotate such that the set screw is advanced into or driven out of an object (e.g., a bone, an implant, or a receiver during a medical procedure). The present solution is not limited to the particulars of this example.

Set screws are well known in the art, and therefore will not be described herein. Any known or to be known set screw can be used herein without limitation. Still, an illustrative set screw600is shown inFIGS. 6-7. The features of set screw600will become apparent as the discussion progresses.

The set screws that are used with the set screw reducer100may be of the Phillip type having cross, hexalobe or star-shaped recesses in their heads. In this regard, a distal end110of the shank102has a tip112that is sized and shaped to fit in the cross, hexalobe or star-shaped recesses of the set screws. A perspective view of an illustrative architecture for the tip112of shank102is provided inFIG. 3. As shown inFIG. 3, the tip112has a star-shape in which a plurality of protrusions300are provided for engaging recess sidewalls of the set screws. This engagement between the tip112and a set screw allows torque to be transferred from the set screw reducer100to the set screw.

The tip112also comprises a means302to frictionally engage a set screw (e.g., set screw600ofFIGS. 6-7) such that: the set screw remains coupled to the set screw reducer100prior to thread engagement between a threaded section (e.g., section602ofFIGS. 6-7) of the set screw and the object, and during the driving of the set screw into the object; a break-off section (e.g., section604ofFIGS. 6-7) of the set screw remains coupled to the set screw reducer100while being broken apart from the threaded section of the set screw via an application of torque thereto, and while the set screw reducer100is being removed away from the object; and the break-off section (e.g., section604ofFIGS. 6-7) of the set screw can be released from the set screw reducer100after the set screw reducer has been moved away from the object. The frictional retention means can include, but is not limited to, a tapered hex shaped tip112, at least one resiliently biased engagement part (e.g., a ball bearing), and/or a rough surface provided on the tip112.

The set screw reducer100is shown inFIGS. 1-4as comprising a frictional retention means including resiliently biased engagement parts. In this architecture, the engagement parts comprise ball bearings304,308that are aligned with each other and disposed on opposing sides402,404of the shank's tip112. The ball bearings304,308are disposed in the shank's tip112so that the ball bearings304,308can slide into and out of the shank's tip112. A resilient member400is disposed between the two ball bearings304,308. The resilient member400is normally in an uncompressed state, and therefore resiliently biases the ball bearings304,308away from each other as shown inFIG. 4. The resilient member400can include, but is not limited to, a coil or spring. The ball bearings304,308and resilient member400are held in position relative to each other by a cap306.

When the shank's tip112of the set screw reducer100is being slid into a socket of a set screw (e.g., set screw600ofFIGS. 6-7), the ball bearings304,308slide against a sidewall (e.g., sidewall702ofFIG. 7) of a socket (e.g., socket700ofFIGS. 6-7) formed in the set screw. This sliding engagement causes the ball bearings304,308to move towards each other and into the shank's tip112. In effect, the resilient member400is compressed by the ball bearings304,308. When the ball bearings304,308become aligned with detents (e.g., detents704,706ofFIG. 7), a groove or an interior circumferential undercut of the set screw, the resilient member400resiliently biases the ball bearings304,308into the detents704,706. At this time, a frictional engagement is provided between the set screw reducer100and the set screw.

An illustration showing the ball bearings304,308of the set screw reducer100disposed in detents704,706of a set screw600is provided inFIG. 8. The present solution is not limited to this particular type of frictional means. Other frictional engagement solutions may alternatively or additionally be used as noted above.

As shown inFIGS. 1-4, the set screw reducer100also comprises a sleeve106slidingly disposed on the shank102. The sleeve106is able to slide in two opposing directions114,116along an elongate length of the shank102. This sliding ability of the sleeve106ensures that the sleeve106does not obstruct, prevent and/or interfere with the coupling of the set screw to the set screw reducer100. In this regard, it should be understood that the sleeve106may be slid in direction116towards handle104prior to when the set screw reducer's operational tip112is inserted into the socket/recess of the set screw. In this way, the sleeve106is moved to a position (e.g., the position shown inFIG. 9) in which (i) the sleeve does not cover or otherwise block an individual's ability to view tip112and/or (ii) a possibility of the sleeve interfering with a coupling between the set screw reducer and the set screw is decreased or eliminated. The sleeve106may be maintained in this position while a frictional engagement between the set screw reducer100and the set screw is being established.

Notably, the sleeve106is provided to prevent or substantially prevent splaying (or spreading outward) of a receiver (e.g., receiver900ofFIG. 9) while the set screw (e.g., set screw600ofFIGS. 6-7) is being driven into the same via the set screw reducer100. Illustrations showing the set screw reducer being used to drive a set screw into a receiver are provided inFIGS. 9-16.

As shown inFIG. 9, a set screw600is frictionally coupled to the set screw reducer100in the manner described above. As such, the components100,600are simultaneously or concurrently moved in a direction902towards the receiver900during a set screw driving process as also shown inFIG. 9.

In some scenarios, a sleeve106of the set screw reducer100may slidingly move in direction902towards receiver900along the elongate length of the shank102while the components100,600are being moved towards the receiver900. The sliding movement of the sleeve106may be caused by a gravitational force being applied thereto. The present solution is not limited in this regard. For example, the sleeve106could be held (e.g., manually or via a mechanical means (e.g., a depressible post of the shank)) at a certain location on shank102until a later time in the process as discussed below.

Once the set screw600is aligned and in contact with a threaded hole904of the receiver900, an individual applies a rotational force to the set screw reducer100(e.g., directly via handle104or indirectly via use of an external instrument or tool). This rotational force is applied by rotating the set screw reducer100in a counter clockwise direction1000(not shown) or alternatively in a clockwise direction (shown inFIG. 10). This rotational force or torque is transferred from the set screw reducer100to the set screw600, and causes a threaded portion602of the set screw to threadingly engage threads906of the receiver900.

Rotation of the set screw600is continued as shown inFIG. 10so that the set screw600abuts a bar, rod or post1002that is at least partially inserted through channels formed between sidewalls1004,1006of the receiver900. Thereafter, the sleeve106is slidingly moved in direction902towards receiver900along the elongate length of the shank102. The sliding movement of the sleeve106may be caused manually by the individual or caused by a gravitational force being applied thereto. The sleeve106is slid in direction902until either (i) its internal engagement surface1100abuts an engagement surface1102of the receiver900or (ii) stop structures (not shown inFIGS. 9-16) (e.g., one or more protruding structures) of the shank102prevent further movement of the sleeve106in direction902. In either case, top portions1104of the receiver's sidewalls1004,1006are received in a recess1106of the sleeve106, as shown inFIG. 11. Consequently, the receiver's top portions1104are enclosed by a sidewall1108of the sleeve106. Notably, the sleeve sidewall1108prevents or substantially prevents the splaying of the receiver's top portions1104by the set screw reducer100as the set screw is being advanced through the threaded hole904, as will become apparent with the following discussion.

As shown inFIGS. 12-14, the set screw reducer100is continuously rotated so as to advance the set screw600through a threaded hole904of the receiver900. During this set screw advancement, the set screw600applies a pushing force in direction902directly to the bar/rod/post1002as it is being advanced through the threaded hole904. This pushing force causes the bar/rod/post1002to travel in direction902along with the set screw600towards a distal end1200of the receiver900.

Also during the set screw advancement process, the receiver900applies a pushing force on the sleeve106such that the sleeve slides in direction1202along the elongate length of the shank102. In effect, the receiver's top portions1104are continuously disposed in the sleeve106while the set screw is being advanced through the threaded hole904, as shown inFIGS. 12-14. Consequently, the sleeve106provides a means to resist the outward splaying of the receiver's top portions1104with the set screw reducer100throughout the set screw advancement process, and thereby also facilitates an increase speed and efficiency of the set screw advancement process.

As shown inFIG. 14, the set screw600is then tightened against the bar/rod/post1002to prevent the bar/rod/post from moving relative to the object1400(e.g., a screw1402with a crown1404). The set screw600exerts a compression or clamping force to the bar/rod/post1002. In this way, the bar/rod/post1002is securely retained in a given position relative to the object1400by the set screw600and the receiver900.

Once the set screw600is tightened against the bar/rod/post1002, the set screw reducer100is removed from the receiver900, as shown byFIGS. 15-16. In this regard, a pulling force is applied to the set screw reducer100in direction1500. This pulling force causes the frictional engagement between the set screw reducer100and set screw600to be discontinued, i.e., the set screw reducer's tip112is pulled out of the recess/socket of the set screw600.

Another tool (not shown) may then be used to apply torque to the set screw so as to (i) cause the break-off section604of the set screw to break away from the threaded section602of the set screw, and (ii) remove the break-off section604of the set screw from the threaded hole904of the receiver900. The present solution is not limited in this regard. Alternatively, the set screw reducer100is used instead of the additional tool for performing actions (i) and (ii).

Yet another tool may be used to apply a lateral force to the receiver900so as to (i) cause the break-off section1600of the receiver to break away from the retainer section1602of the receiver, and (ii) move the break-off section1600away from the object.

Notably, during some medical procedures, a plurality of set screws may need to be advanced through a plurality of receivers. A plurality of set screw reducers100can be concurrently used in such scenarios to advance the set screws through receivers at the same time or in an alternating manner during a single process. For example, a first set screw reducer is used to advance a first set screw by a first amount during a first time period, and a second set screw reducer is used to advance a second set screw by a second amount during a second subsequent time period, where the first and second amounts are the same or different. This process is repeated until the first and second set screws are advanced by a desired amount into one or more objects. The present solution is not limited to the particulars of this example.

Referring now toFIG. 17, there is provided a flow diagram of an illustrative method1700for advancing a set screw (e.g., set screw600ofFIG. 6-7) in an object (e.g., receiver900ofFIGS. 9-16) (e.g., during a medical procedure). Method1700begins with1702and continues with1704where a sleeve (e.g., sleeve106ofFIGS. 1-4) of a set screw reducer (e.g., set screw reducer100ofFIGS. 1-4) is slid along an elongate length of a shank (e.g., shank102ofFIGS. 1-4) of the set screw reducer in a direction (e.g., direction116ofFIG. 1) away from the shank's tip (e.g., tip112ofFIG. 1) until the sleeve is in a positon (e.g., the position shown inFIG. 9) which decreases or eliminates the sleeve's interference with a coupling between the set screw reducer and the set screw. Notably, the sleeve is integrated with the operational parts (e.g., handle104and shank102ofFIGS. 1-4) of the set screw reducer such that the set screw reducer has multiple purposes. These purposes include, but are not limited to, advancing a set screw into an object, removing a set screw from an object, and/or preventing splaying of at least one sidewall of the object while the torque is being transferred from the set screw reducer to the set screw.

Next in1706, the shank's tip is disposed in a socket (e.g., socket700ofFIGS. 6-7) of the set screw. A frictional engagement is established in1708between the shank's tip and the set screw. In some scenarios, the frictional engagement is established by resiliently biasing at least one engagement part of the set screw reducer into a detent or a groove (e.g., detent or groove704,706ofFIG. 7) formed in a sidewall (e.g., sidewall702ofFIG. 7) of the set screw's socket. The at least one engagement part can include, but is not limited to, a ball bearing (e.g., ball bearing304,308ofFIG. 3) that is resiliently biased by a resilient member (e.g., resilient member400ofFIG. 4) in a direction out and away from the shank tip. The present solution is not limited to the particulars of this scenario.

In1710, the sleeve is caused to slidingly engage the shank of the set screw reducer and move in a direction (e.g., direction114ofFIG. 1) towards the shank's tip. A rotational force is then applied in1712to the handle of the set screw reducer. The rotational force can be applied with or without the assistance of an external instrument or tool (e.g., wrench500ofFIG. 5). In this regard, it should be understood that an end (e.g., end502,504ofFIG. 5) of the external instrument or tool can be received in a socket (e.g., socket200ofFIG. 2) formed in the handle of the set screw reducer, and thereafter used to cause rotation of the handle and shank of the set screw reducer.

In1714, torque is transferred from the set screw reducer to the set screw such that the set screw is advanced in a threaded hole (e.g., threaded hole904ofFIG. 9) of the object. The torque is transferred from the set screw reducer to the set screw in response to a rotational force being applied to a handle of the set screw reducer.

In1716, the sleeve of the set screw reducer is used to prevent or substantially prevent splaying of at least one sidewall (e.g., sidewall1004,1006ofFIG. 10) of the object while the torque is being transferred from the set screw reducer to the set screw. As part of splaying prevention, the sleeve resists an outward bending of the at least one sidewall of the object throughout the advancement of the set screw in the object. In this regard, it should be understood that: a free end (e.g., end1104ofFIG. 11) of the at least one sidewall of the object is continuously disposed within a recess (e.g., recess1106ofFIG. 11) formed in the sleeve, while the set screw reducer is being used to advance the set screw in the object; and the free end of the at least one sidewall of the object causes the sleeve to move along an elongate length of the shank in a direction away from the shank tip while the set screw is being advanced in the object. Subsequently,1718is performed where method1700ends or other actions are performed.