Flexible sleeve for bone fixation and related systems and methods - Patents.com

Abstract

A flexible tubular member for guiding the insertion of an instrument into a bone screw secured within a bone includes a tubular body that is flexible and constructed from a woven material and defines a longitudinal axis. The tubular body also defines proximal and distal ends opposed to one another along the longitudinal axis. The tubular body further defines a guide channel extending from a proximal opening at the proximal end to a distal opening at the distal end. An attachment member is disposed at the distal end of the tubular body and configured to couple the distal end to a proximal portion of the bone screw. The attachment member has an annular shape about the guide channel and is configured to expand in response to a predetermined tension applied to the tubular body to separate from the bone screw.

Description

[Technical Field]

[0001] The present invention relates to a flexible sleeve for coupling to a bone fixation device, and in particular for extending from an implanted bone fixation device to provide a guide channel through soft tissue between the bone fixation device and an ex vivo location. [Background technology]

[0002] Traditional spinal surgery is performed using open procedures, resulting in relatively large incisions, destruction, or resection of substantial soft tissue and prolonged patient recovery times. Minimally invasive techniques, particularly for spinal surgery, are becoming increasingly popular, in which relatively small incisions and surgical pathways are used to perform surgical procedures on patients, generally resulting in smaller or fewer relatively small incisions, less soft tissue retraction and resection, and shorter patient recovery times compared to open procedures. Minimally invasive procedures can, in certain circumstances, achieve comparable or improved long-term surgical results compared to open procedures and may offer short-term benefits including reduced postoperative pain, reduced use of postoperative anesthesia, reduced tissue destruction, thereby reducing scar tissue and potential benefits if revisions are necessary, reduced blood loss, accelerated recovery time, shorter hospital stays, and cosmetically appealing smaller incisions. However, because the patient's soft tissue often limits the surgeon's ability to view the surgical site, one or more smaller incisions reduce the surgeon's direct line of sight to the surgical site.

[0003] A common procedure in spinal surgery involves securing screws to several vertebrae and fixing the screws and vertebrae relative to one another with rods. Such spinal structures are typically implanted by attaching a surrounded or substantially surrounded rigid cannula or sleeve to the screw, such that the surrounded rigid cannula or sleeve forms a surgical pathway through the soft tissue and allows the surgeon access to the surgical site. Minimally invasive spinal instruments utilized for such procedures, such as those employing K-wires, can be difficult to assemble, tend to be bulky, and can extend a significant distance from the patient's skin, limiting the surgeon's ability to visualize the surgical site. They can also, as a result of their size and material composition, interfere with imaging using a C-arm or fluoroscopy, and can be difficult to separate from the screw at the end of the procedure. Furthermore, current minimally invasive fixation of screws and placement of rods in spinal surgery often results in undesirable levels of trauma to the patient's soft tissue in and around the surgical site along the surgical pathway and in close proximity to the incision. Once assembled for rod insertion, these conventional minimally invasive systems are typically locked in place, limiting the surgeon's options in adapting their surgical technique to a particular patient's anatomy or adapting the instruments to implant components in a manner that will benefit the patient. Summary of the Invention [Means for solving the problem]

[0004] According to one embodiment of the present disclosure, a flexible tubular member for guiding insertion of an instrument into a bone screw fixed in a bone is flexible; textile materialsThe bone screw includes a tubular body constructed from a tubular member and defining a longitudinal axis. The tubular body also defines proximal and distal ends opposed to one another along the longitudinal axis. The tubular body further defines a guide channel extending from a proximal opening at the proximal end to a distal opening at the distal end. The attachment member is disposed at the distal end of the tubular body and configured to couple the distal end to a proximal portion of the bone screw. The attachment member has an annular shape around the guide channel and is configured to expand in response to a predetermined tension applied to the tubular body to separate from the bone screw.

[0005] According to another embodiment of the present disclosure, a system for bone fixation includes a bone screw having a head portion and a shaft extending distally therefrom toward a distal end of the bone screw. The head portion also defines a tapered portion that narrows distally. The system is flexible and textile materials The bone screw includes a sleeve constructed from a bone screw having a longitudinal axis and a proximal end and a distal end opposed along the longitudinal axis. The sleeve also defines a guide channel extending from a proximal opening at the proximal end to a distal opening at the distal end. A mounting ring is disposed at the distal end of the sleeve and configured to couple the distal end of the sleeve to a tapered portion of the bone screw. The mounting ring extends annularly around the guide channel and is configured to expand in response to a predetermined tension applied to the sleeve to separate the sleeve from the bone screw.

[0006] According to an additional embodiment of the present disclosure, a method for securing a bone screw to bone includes attaching a flexible sleeve to a head of the bone screw such that the sleeve extends proximally from the bone screw. Attaching the sleeve includes advancing the bone screw through a guide channel defined by the sleeve until a distal face of the head contacts an attachment ring disposed at a distal end of the sleeve. The attachment ring defines an inner diameter smaller than a maximum diameter of the head. The method also includes inserting a driver into a socket defined by the head, advancing the bone screw through soft tissue to a fixation site in the bone, and rotating the driver about a central axis, thereby threading the shaft of the bone screw into the fixation site such that the sleeve extends through the soft tissue and a proximal end of the sleeve is disposed ex vivo. The method also includes applying tension to the sleeve, thereby expanding the attachment ring to separate the sleeve from the bone screw. [Brief explanation of the drawings]

[0007] The foregoing summary and the following detailed description of exemplary embodiments of the present application will be better understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the structure of the present application, there are shown in the drawings exemplary embodiments. It should be understood, however, that the present application is not limited to the precise arrangements and instrumentalities shown. In the drawings: [Figure 1] FIG. 1 is a rear plan view of a spinal surgery system including a flexible sleeve extending from an implanted bone fixation device to an ex vivo location, according to one embodiment of the present disclosure. [Figure 2] 2 is a perspective view of the flexible sleeve shown in FIG. 1, the sleeve being shown in a theoretical neutral configuration. [Figure 3] 2 is a perspective view of the ex vivo portion of the flexible sleeve shown in FIG. 1. FIG. [Figure 4] FIG. 4 is an enlarged perspective view of the flexible sleeve shown in FIG. 3. [Figure 5] FIG. 5 is a side view of a prior art bone fixation device for use with the flexible sleeve shown in FIGS. 1-4. [Figure 6]6 is a perspective view of a distal portion of a flexible sleeve coupled to the head of the bone anchoring device shown in FIG. 5. FIG. [Figure 7] FIG. 5 is an exploded perspective view of a spinal surgery system using the flexible sleeve shown in FIGS. [Figure 8] 8 is a plan view of a sleeve coupled to a bone fixation device and a screwing tool of the spinal surgery system shown in FIG. 7. [Figure 9] 8 is a plan view of a sleeve for guiding insertion of a second screwing tool carrying an extension member of the spinal surgical system shown in FIG. 7 into a bone fixation device. [Figure 10] 10 is a partial cross-sectional side view of the extension member shown in FIG. 9 coupled to a bone fixation device, with the flexible sleeve omitted for purposes of illustration. [Figure 11] 10 is a plan view of the extension member shown in FIG. 9 coupled to a bone fixation device with the second threaded member removed from the flexible sleeve. [Figure 12] 12 is an enlarged perspective view of a distal portion of the extension member shown in FIG. 11 shown within a sleeve and coupled to a bone fixation device. [Figure 13] 13 is a perspective view of a distal portion of the flexible sleeve shown in FIG. 12 coupled to a bone fixation device. [Figure 14] 14 is a perspective view of the distal portion of the flexible sleeve shown in FIG. 13 with the attachment members of the sleeve broken and the sleeve partially withdrawn to expose the distal portion of the extension member coupled to the bone fixation device. [Figure 15] FIG. 8 is a perspective view of various components of the spinal surgery system shown in FIG. 7 attached to adjacent vertebral bodies during an intermediate stage of spinal surgery, according to an embodiment of the present disclosure. [Figure 16] FIG. 16 is a perspective view of various components of the spinal surgery system shown in FIG. 15 attached to adjacent vertebral bodies during the final stage of a spinal surgery according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present disclosure may be understood more readily by reference to the following detailed description in conjunction with the accompanying drawings and examples, which form a part of this disclosure. It is to be understood that the present disclosure is not limited to the specific devices, methods, applications, conditions, or parameters described and / or illustrated herein, and that the terminology used herein is for the purpose of describing specific embodiments, by way of example, only and is not intended to limit the scope of the disclosure. Also, as used in the specification, including the appended claims, the singular forms "a," "an," and "the" include plurals, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise.

[0009] The term "plurality," as used herein, means more than one. When a range of values ​​is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed in approximation, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. All ranges are inclusive and combinable.

[0010] When used herein with respect to dimensions, angles, and other features, the terms "about" and "substantially" take into account manufacturing tolerances. Furthermore, the terms "about" and "substantially" may include 10% greater or less than the stated dimension or angle. Furthermore, the terms "about" and "substantially" may equally apply to the specific values ​​stated.

[0011] The embodiments described below relate to a flexible sleeve configured to couple to an implantable member, such as a bone fixation device, and to provide a guide channel through soft tissue to guide the insertion of instrumentation and / or additional implantable components through the soft tissue to the implantable member. Current spinal fixation procedures, such as spinal fusion procedures, particularly minimally invasive spinal fusion procedures, tend to use percutaneous pedicle screws for fixation to the pedicles of one or more vertebral bodies at a surgical treatment site. Such percutaneous pedicle screws generally comprise a bone screw having a reduced-profile head and a separate extension member that can be coupled to the reduced-profile head of the bone screw. These extension members tend to define a distal fixation head that can be severed or otherwise separated from the remainder of the extension member. The fixation head generally defines a U-shaped channel for receiving a spinal rod therein to fix the relative positions of adjacent vertebral bodies. Alternatively, the fixation head may define a C-shaped channel, such as for use with a screw system configured for lateral loading of a spinal rod therein. The fixation head may be configured for polyaxial angulation with respect to a bone screw to provide excellent adjustability for the orientation of a spinal rod receiveable therein.

[0012] The current state of the art prefers attaching extension members to bone screws before implanting them. However, this technique can result in bulky components extending outward from the patient, particularly as the number of inserted pedicle screws and attached extension members increases, thereby creating a physical obstacle at the surgical site and obstructing the surgeon's direct line of sight. This technique can also exert excessive force on soft tissue, potentially resulting in ischemia therein. Furthermore, these components tend to be radiopaque, thus similarly interfering with electronic imaging of the surgical site, such as radiology and fluoroscopy. However, coupling an extension member to a bone screw in vivo also presents challenges in that it tends to be difficult to position the head of the bone screw within the patient in a blind spot, particularly when the surgeon has limited percutaneous access to the implanted bone screw. Furthermore, coupling an extension member to a bone screw head in vivo can be complicated by fluid and / or tissue that may be interposed between the mating surfaces of the bone screw and the extension member.

[0013] The flexible sleeve disclosed herein provides a reliable guide channel through soft tissue, such as for inserting an extension member. In this manner, bone screws can be implanted prior to coupling with the extension member, thereby reducing physical obstruction at the surgical site and allowing easier movement for the surgeon during surgery. Furthermore, the flexible material of the sleeve allows its ex vivo portion to lie substantially flat along the outer surface of the patient's skin, thereby also reducing visual obstruction of the surgical site, including electronic visualization, e.g., fluoroscopy. Furthermore, the flexible sleeve material is preferably constructed to allow the sleeve to expand radially (i.e., outward) without reducing its overall length, thereby reducing friction imposed on the surrounding soft tissue.

[0014] 1 , an exemplary embodiment of a bone fixation system 100 includes a flexible tubular body 2, also referred to herein as a flexible sock or flexible sleeve 2, configured to couple to a bone fixation device 4, such as a bone screw, securable at a target site within a bone 102. The sleeve 2 is configured to extend from its distal end 6, which is attached to the bone fixation device 4, proximally through soft tissue 104 to a proximal end 8, which is positioned in an ex vivo position relative to the patient's anatomy. The sleeve 2 is configured to guide insertion of implant components and / or instruments through the soft tissue 104 and into the bone fixation device 4. In the illustrated embodiment, the bone fixation device 4 is a pedicle bone screw configured to be inserted into the vertebral body 105 through its pedicle, and the sleeve 2 extends proximally from the pedicle screw 4 through the soft tissue 104 along the orbital axis 106 to an incision 108 at a skin line 110 of the patient's anatomy, and further extends from the incision 108 to the proximal end 8. As shown, the sleeve 2 is preferably configured such that its proximal ex vivo portion can be folded away from the orbital axis 106 and placed along the outer surface of the patient's skin 110.

[0015] Referring now to FIG. 2 , sleeve 2 is elongated along a longitudinal direction L and defines a longitudinal axis X oriented along the longitudinal direction L. Distal end 6 and proximal end 8 of sleeve 2 oppose one another along the longitudinal direction L, such that distal end 6 is spaced apart from proximal end 8 in a distal direction D along the longitudinal direction L, and proximal end 8 is spaced apart from distal end 6 in a proximal direction P along the longitudinal direction L. It should be understood that proximal direction P and distal direction D oppose one another and are each unidirectional components of the longitudinal direction L, which is bidirectional. Similarly, it should be understood that FIG. 2 shows sleeve 2 in a theoretical neutral configuration, free of external forces (including gravity).

[0016] The sleeve 2 further defines a guide channel 10 that extends along a longitudinal axis X from a distal opening 12 at the distal end 6 to a proximal opening 14 at the proximal end 8. The sleeve 2 also defines an outer surface 16 and an inner surface 18 that are spaced apart along a radial direction R that is perpendicular to the longitudinal axis X (and thus perpendicular to the longitudinal direction L). A wall 20 of the sleeve 2 extends radially (i.e., along the radial direction R) between the outer surface 16 and the inner surface 18. It should be understood that the inner surface 18 defines the guide channel 10.

[0017] The sleeve 2 includes an attachment member 22 at or adjacent the distal end 6 for coupling the distal end 6 to a proximal portion of the bone fixation device 4, as described in more detail below. The proximal end 8 of the sleeve 2 preferably includes an introduction member 24 configured to facilitate insertion of an instrument into the guide channel 10. As shown, the introduction member 24 may be a ring that extends annularly around the guide channel 10 and defines the proximal opening 14. The ring 24 is preferably configured to provide a funnel-shaped structure at the proximal opening 14. The sleeve 2 defines a length L1 measured along a longitudinal direction L from the proximal end 8 to the distal end 6. The sleeve 2 also defines a cross-sectional dimension R1 measured along a radial direction R.

[0018] The sleeve 2 is preferably textile materials Constructed from textile materials can be a woven, braided, knitted, and / or electrospun structure. textile materials may be an implantable-grade biocompatible material such as, by way of non-limiting example, polyethylene terephthalate (PET), ultra-high-molecular-weight polyethylene (UHMWPE), polydioxanone (PDS), polypropylene (PP), polyester, and nylon. However, because sleeve 2 is configured for temporary use during a surgical procedure and not as a permanent or long-term implant, textile materials It should be understood that the material does not have to be an implantable grade material, but can be a medical grade material and / or a biodegradable material.

[0019] The sleeve 2 is also preferably configured to be radially flexible, in particular to be able to expand radially (i.e., along the radial direction R) and circumferentially while maintaining a substantially constant length. In other words, the sleeve 2 is preferably constructed such that the cross-sectional dimension R1 is configured to expand while the length L1 remains substantially constant. Such a configuration can be provided by the manner in which the sleeve 2 is constructed. As a non-limiting example, the sleeve 2 textile materialsThe sleeve 2 may be constructed by knitting polyethylene terephthalate (PET) fibers in a weft knit pattern that provides high radial extensibility. Other materials and structures may be used to provide the sleeve 2 with high radial extensibility. In this manner, the sleeve 2 may radially expand to accommodate passage of implanted components and / or instruments through the guide channel 10 without substantially lengthening or shortening the length L1, thereby avoiding or at least reducing friction between the outer surface 16 of the sleeve 2 and the soft tissue 104 adjacent the sleeve 2. The sleeve 2 is also preferably configured to collapse in a substantially flat manner within the soft tissue 104 (i.e., without folding over on itself). In this manner, the sleeve 2 may be configured to avoid compression of the soft tissue 104 surrounding the sleeve 2. Additionally or alternatively, the material of the sleeve 2 may also be configured to prevent or at least reduce moisture penetration into the guide channel 10, for example, by employing a low porosity. In other embodiments, the sleeve 2 need not inhibit moisture within the guide channel 10. Furthermore, sleeve 2 is preferably configured to be substantially radiolucent, thereby avoiding obstruction of fluoroscopic images. Additionally or alternatively, one or more portions of sleeve 2 may be partially radiopaque so as to be visible in fluoroscopic or X-ray images. Furthermore, sleeve 2 may be configured to be at least partially visible in magnetic resonance imaging (MRI). This may include, for example, by way of non-limiting example: textile materials This can be achieved by incorporating a metal filament into the sleeve 2. Additionally or alternatively, the sleeve 2 may deliver antibiotic and / or antiseptic solutions to provide therapeutic benefit to soft tissue in contact with or adjacent to the sleeve 2. Furthermore, the sleeve 2 textile materials may optionally include light emitting fibers, such as for providing illumination within the guide channel 10 and / or for emitting ultraviolet (UV) light to sterilize soft tissue adjacent to the sleeve 2.

[0020] 3 and 4 , the sleeve 2 can also be configured so that any portion thereof, or at least any portion between the attachment member 22 and the introduction member 24, is configured to be substantially flat when in its resting configuration when its guide channel 10 is unoccupied. Thus, a physician can lay the ex vivo portion of the sleeve 2 extending from the incision 108 substantially flat along the outer surface of the patient's skin 110. In this manner, the sleeve 2 can advantageously provide access to the implanted bone fixation device 4 while reducing disturbance to the surgical site. In other words, the ex vivo portion of the sleeve 2 can be folded out of the way until access to the bone fixation device 4 is desired. If necessary, a physician can manually flatten the ex vivo portion of the sleeve 2, such as by running a finger or thumb along the outer surface 16 of the sleeve 2 in a manner that presses the sleeve 2 down against the skin 110, or by pinching the sleeve 2 between the thumb and index finger and running the thumb proximally toward the proximal end 8, as non-limiting examples.

[0021] Referring now to FIG. 5 , the bone fixation device 4 may be a bone screw, such as a pedicle screw, having a head portion 30 and a shaft 32 extending from the head portion 30 in a distal direction D. A proximal surface 34 of the head portion 30 defines the proximal end of the bone screw 4. The proximal surface 34 may therefore be referred to as the proximal end of the bone screw 4. The shaft 32 preferably defines external threads 36 for engaging bone material at the target site. The external threads 36 may be helical, as shown, and may extend toward a distal tip 38 that defines the distal end of the bone screw 4. The distal tip 38 may therefore be referred to as the distal end of the bone screw 4. The bone screw 4 defines a central thread axis 40 along a longitudinal direction L. Bone screw 4 preferably defines a cannulation along central thread axis 40 for receiving a guide wire, such as a Kirschner wire or "K-wire," to guide insertion of bone screw 4 into the target site.

[0022] The head 30 of the bone screw 4 is preferably configured for attachment to an extension member that extends from the bone screw to an ex vivo location. Accordingly, the head 30 shown throughout the illustrated embodiments does not include external threads, although it should be understood that the sleeve 2 may be used with threaded screw heads. The head 30 defines an outer surface 42 that is preferably smooth and has a curved or hemispherical shape to facilitate rotation relative to the extension member, as described in more detail below. Accordingly, the head 30 defines a maximum width W1 and a tapered portion 43 that narrows distally (i.e., in the distal direction D) to a neck 45 having a second width W2 that is preferably less than the maximum width W1.

[0023] The head portion 30 also preferably defines one or more sockets 44a, 44b for receiving one or more complementary driving tools. As shown, the head portion 30 may define a first socket 44a configured to receive a first driving tool, such as a driver for driving the bone screw 4 into a target site within the bone 102. The head portion 30 may also define a second socket 44b configured to receive a second driving tool, such as a driver for driving an extension member into engagement with the head portion 30, as described in more detail below. Each socket 44a, 44b may define a threading surface configured to mate with a corresponding bit of an associated driving tool. For example, by way of non-limiting example, the threading surface of the first socket 44a may be a star-hex pattern configured to mate with a star-hex driving bit, and the threading surface of the second socket 44b may define female threads configured to engage with male threads on a threaded post driving bit. It should be understood that other threaded surface patterns are within the scope of the present disclosure. The bone screw 4 and its features may be configured as more fully described in U.S. Patent No. 8,262,662, issued September 11, 2012 to Beardsley et al. (hereinafter the "Beardsley reference"), U.S. Patent No. 10,136,923, issued November 27, 2018 to Keyer et al. (hereinafter the "Keyer reference"), and U.S. Patent Publication No. 2019 / 0150989, filed May 23, 2019 to Biester et al. (hereinafter the "Biester reference"), the entire disclosures of each of which are incorporated herein by reference.

[0024] 6 , the sleeve 2 is configured to couple to the bone fixation device 4, particularly at or adjacent its head portion 30. As shown, the attachment member 22 is preferably configured to couple to the bone screw 4 at a location distally spaced from the maximum width W1 of the head portion 30, such as, by way of non-limiting example, at the neck portion 45 as shown or at the tapered portion 43 of the head portion 30. The attachment member 22 preferably defines an annular shape that extends around the guide channel 10 at or adjacent the distal end 6 of the sleeve 2. For example, the attachment member 22 may be an annular ring or band and may define a distal opening 12, although in other embodiments, the attachment member 22 may be spaced proximally from the distal opening 12. The mounting member 22 may define an inner diameter D1 equal to or slightly larger than the second width W2 of the bone fixation device 4, whereby the inner surface of the mounting member 22 preferably forms a snug fit with the outer surface of the bone fixation device 4, such as at the neck portion 45 or the tapered portion 43 of the head portion 30.

[0025] The attachment member 22 is also configured to expand, particularly by increasing its inner diameter D1, in response to a separation force, such as a predetermined tension applied to the sleeve 2 along the longitudinal axis X. In this manner, a physician can apply a predetermined tension to the sleeve 2, such as by pulling on the introducing member 24, when it is desired to separate the sleeve 2 from the bone fixation device 4. As a non-limiting example, the attachment member 22 may be defined by an adhesive, epoxy, or other material configured to be applied in a liquid or semi-liquid phase in an annular ring around the guide channel 10 or at least partially around the guide channel 10 and further configured to harden to a solid phase. In other embodiments, the attachment member 22 may be defined by a portion of the sleeve 2 that is at least substantially melted and then solidified in an annular ring around the guide channel 10 or at least partially solidified around the guide channel 10. The exemplary attachment members 22 described above may be configured to expand by breaking, tearing, ripping, or otherwise undergoing a mechanical failure mode. In additional embodiments, attachment member 22 may be a spring member, such as an annular or semi-annular spring, such as a slotted or C-ring, or a spiral spring, configured to open or otherwise expand (such as by expanding its inner diameter D1) in response to a predetermined tension. These embodiments using spring members as attachment member 22 may be advantageous because they do not have to undergo a mechanical failure mode to expand and separate from bone screw 4. It should be understood that other techniques for constructing attachment member 22 are within the scope of this disclosure.

[0026] 7-16, further uses of spinal fixation system 100 in accordance with a representative surgical procedure will be described. In this example, the surgical procedure is a spinal fixation procedure, such as to provide spinal decompression, although it should be understood that sleeve 2 may be used with similar benefit for other types of surgical procedures.

[0027] Referring now to FIG. 7 , the spinal fixation system 100 may include a sleeve 2 and a bone fixation device 4 as described above, and may further include a first screwing member, such as a first screwing bit 120, having a distal end 122 configured to engage with the first socket 44a of the bone fixation device 4 and a proximal end 124 configured to engage with a screwing tool.

[0028] The system 100 may further include an extension member 130 elongated along the longitudinal direction L and configured to couple to the head portion 30 of the bone fixation device 4. The extension member 130 defines a proximal end 132 and a distal end 134 spaced apart from one another along the longitudinal direction L. The extension member 130 may include a main portion 136 extending distally from the proximal end 132, a fixation head portion 138 extending to and defining the distal end 134, and a weakened portion 140 interposed between the main portion 136 and the fixation head portion 138. The extension member 130 may also define a longitudinally elongated channel 142 extending from, for example, the proximal end 132 along the main portion 136 and extending along a portion of the fixation head portion 138. The elongated channel 142 also extends from opposing sides 144 a, 144 b of the main portion 136 and the fixation head 138, respectively, along a transverse direction T that is substantially perpendicular to the longitudinal direction L. In this manner, the elongated channel 142 may define a pair of elongated tabs along the main portion 136. Accordingly, the main portion 136 may also be referred to as “extension tabs” 136. The elongated channel 142 is configured for guided insertion of a spinal rod into the fixation head 138, as described in more detail below.

[0029] The fixation head 138 preferably defines a chamfered surface 146 extending to the distal end 134 to facilitate advancement of the extension member 130 through the sleeve 2. The fixation head 138 also defines an attachment formation, such as a receptacle portion 148, configured to receive the head portion 30 of the bone fixation device 4. The weakened portion 140 is configured to break in response to a predetermined force, such as a predetermined torsional force and / or a tensile force, thereby separating the extension tab 136 from the fixation head 138 after the fixation head 138 couples to the bone fixation device 4. The extension member 130, including the extension tab 136 and the fixation head 138, is more fully described in the Biester and Beardsley references.

[0030] The system 100 may include a second screwing member, such as a second screwing tool 150, configured to extend longitudinally within the elongated channel 142 of the extension member 130 to couple with and advance the extension member 130 through the guide channel 10 of the sleeve 2 and to the head portion 30 of the bone fixation device 4. The second screwing tool 150 may include a handle 152 disposed at its proximal end. The handle 152 may define a proximal attachment formation, such as an annular recess 154, for attachment to the proximal end 132 of the extension member 130. The second screwing tool 150 may further define a cannulation portion 153 extending from the proximal end to the distal end of the second screwing tool 150. The cannulation portion 153 may be sized to receive the first screwing bit 120 therein. In this manner, the second screwing tool 150 can advance the extension member 130 along the first screwing bit 120 through the guide channel 10 of the sleeve 2 while its distal end 122 is engaged with the first socket 44a of the bone fixation device 4.

[0031] The distal end of the second screwing tool 150 may define a distal attachment formation, such as a threaded mounting post 155 having external threads for engaging the internal threads of the second socket 44b of the bone fastener 4, thereby positioning the head portion 30 of the bone fastener 4 within the receptacle portion 148 of the fixation head portion 138. Such threaded engagement between the threaded mounting post 155 and the internal threads of the second socket 44b effectively holds the bone fastener 4 in place and prevents the bone fastener 4 from angulating relative to the second screwing tool 150 while additional connecting elements are attached to the fixation head portion 138.

[0032] The second screwing tool 150 may also include one or more additional formations for supporting one or more associated coupling elements for securely coupling the fixation head 138 to the head 30 of the bone fixation device 4. For example, the second screwing tool 150 may include a first boss 156 for supporting a retaining member 160, such as a snap-on collar, for insertion onto the head 30 in a manner to reside within the receptacle 148 between the fixation head 138 and the head 30 of the bone fixation device 4. The second screwing tool 150 may also include a second boss 158 for supporting a locking member 170, such as a locking cap, for engaging a complementary locking formation on the fixation head 138 in a manner to retain the spinal rod within the channel 142 of the fixation head 138, as described in more detail below. It should be understood that the second screwing tool 150 may also include a formation configured to engage a complementary formation on the main portion 136 of the extension member 130 to apply a predetermined twisting and / or pulling force thereto to separate the main portion 136 from the fixed head portion 138.

[0033] 8 , the physician may engage the first screw bit 120 with the bone fixation device 4 by, in particular, inserting the distal end 122 of the bit into the first socket 44 a of the head portion 30 of the bone fixation device 4. In the exemplary embodiment, the bone fixation device 4 is a pedicle screw 4. The physician may then insert the connected pedicle screw 4 and first screw bit 120 into the guide channel 10 of the sleeve 2 through its proximal opening 14 and advance the pedicle screw 4 and first screw bit 120 distally through the guide channel 10 until the attachment member 22 engages a desired portion of the pedicle screw 4, such as the neck portion 45 or tapered portion 43 of the head portion 30 (as more clearly shown in FIG. 6 ). With the pedicle screw 4, first screw bit 120, and sleeve 2 coupled in this manner, the physician can use the first screw bit 120 to advance the pedicle screw 4 and a distal portion of the sleeve 2 through an incision, such as a stab incision, through the soft tissue 104 along the trajectory axis 106 to a target site in the first vertebral body 105, and screw the screw shaft 32 into the bone material 102 at the target site. After the shaft 32 has been inserted to a desired depth within the first vertebral body 105, the first screw bit 120 can be withdrawn proximally from the guide channel 10, leaving the distal portion of the sleeve 102 along the trajectory axis 106 and into the soft tissue 104.

[0034] With the first screw bit 120 removed from the sleeve 2, the physician may lay the ex vivo portion of the sleeve 2 flat and out of the way along the outer surface of the patient's skin, as described above. The physician may then use a screwing tool, such as the first screw bit 120, to couple a second pedicle screw 4 to the second sleeve 2 and insert the second pedicle screw 4 into a second target site within the bone 102, such as into another pedicle, such as the pedicle of the second vertebral body 105 or the pedicle opposite the first vertebral body 105, from which the sleeve extends proximally through the soft tissue 104 to the second ex vivo location, similar to the first sleeve 2. The physician may repeat the above steps as necessary to insert additional pedicle screws into additional target sites, with the associated sleeve 2 extending therefrom to their respective ex vivo locations. The physician may lay the ex vivo portion of the sleeve 2 flat and out of the way along the outer surface of the patient's skin to reduce obstruction of the surgical site and may also reduce imaging obstruction.

[0035] If it is desired to couple the extension member 130 to the pedicle screw 4, the physician may ensure that the extension member 130 is properly coupled to the second screwing tool 150. The physician may manipulate and align the ex vivo portion of the sleeve 2 along the trajectory axis 106, such as by lifting the introducer member 24. Referring now to FIG. 9 , with the ex vivo portion of the sleeve 2 aligned, the physician may manipulate the second screwing tool 150 to insert the distal end 134 of the extension member 130 through the introducer member 24 and into the guide channel 10. The physician may further advance the second screwing tool 150 and the extension member 130 coupled thereto in a distal direction until the threaded mounting post 155 engages the second socket 44b of the screw head portion 30.

[0036] 10 , the physician may rotate the second driving tool 150 to thread the threaded mounting post 155 into the internal threads of the second socket 44b until the threaded mounting post 155 is fully seated within the second socket 44b, thereby placing the head 30 at a desired depth within the receptacle portion 148 of the fixation head 138. The collar 160 may be advanced distally along the outer surface 42 of the head 30 until the collar 160 is fully seated against the head 30. In its fully seated position, the inner surface 162 of the collar 160 may extend distally across the location of maximum width W1 and along the tapered portion 43 of the head outer surface 42, while the outer surface 164 of the collar 160 engages the inner surface 149 of the fixation head 138, which defines its receptacle portion 148. The collar 160 of the illustrated embodiment is configured to snap into place on the head 30 once the distal end of the collar 160 passes the location of maximum width W1, thereby providing the physician with tactile feedback and preferably also audible feedback (e.g., a snap or click) indicating when the collar 160 is fully seated against the screw head 30 and the locking head 138. The collar 160 is further configured to provide polyaxial angulation to the locking head 138 relative to the screw head 30, as described more fully in, for example, the Keyer and Biester references.

[0037] 11 and 12 , with the fixation head 138 coupled to the pedicle screw 4, the second driving tool 150 can be decoupled from the second socket 44b and withdrawn from the sleeve 2, leaving the extension member 130 within the sleeve 2 and coupled to the pedicle screw 4. The flexibility of the sleeve 2 allows a physician to manipulate the extension member 130 through the sleeve 2, such as by grasping around the extracorporeal portion of the sleeve 2 including the extension member 130, to polyaxially angle the extension member 130 relative to the pedicle screw 4 as needed, such as to position the elongated channel 146 in a desired orientation for receiving a spinal rod.

[0038] 13 and 14 , when it is desired to remove the sleeve 2, a physician may apply a predetermined tension F1 thereto, thereby breaking the attachment member 22. The physician may then pull out the sleeve 2, thereby exposing the extension tab 136 and the elongated channel 142. In this manner, the sleeve 2 may protect the screw head 30, fixation head 138, and extension tab 136 in vivo until it is desired to insert a spinal rod into the channel 142.

[0039] 15 and 16 , a physician may repeat one or more of the foregoing steps as necessary to insert pedicle screws 4 into multiple vertebral bodies, such as a pair of adjacent vertebral bodies 105, and couple extension members 130 to the pedicle screws 4. It should be understood that a physician may choose to fully or only partially remove the sleeve 2 from the associated extension tab 136 in order to insert a spinal rod into the elongated channel 142. For example, FIG. 15 illustrates a first pair of extension members 130 a with the sleeve 2 fully withdrawn. Relative to these extension members 130 a, an associated spinal rod 180 may be inserted into the elongated channel 142, such as from the proximal end 132 of the extension member 130, and the spinal rod 180 may be advanced distally along the channel 142 until the spinal rod 180 is seated within the channel 142 of the fixation head 138.

[0040] Also shown is a second pair of extension members 130b, one with its associated sleeve 2 fully retracted and the other with its associated sleeve 2 partially retracted, exposing a distal portion of the elongated channel 142. With these extension members 130b, a physician may choose to insert a spinal rod 180 distally along the channel 142 of the extension member 130b from which the sleeve 2 has been fully withdrawn, with the aid of a rod delivery tool 182 or the like. Using the tool 182, the physician may insert the distal end of the rod 180 into the exposed fixation head 138 of the extension member 130b from which the sleeve 2 has only partially withdrawn. The physician may then seat the rod 180 in both of the associated fixation heads 138 as desired. In this manner, at least one of the sleeves 2 may continue to provide a barrier between the soft tissue 104 and the associated extension member 130. It should be noted that by advancing the spinal rod 180 distally along only one of the second pair of extension members 130b, less compressive force may be applied to the soft tissue adjacent to, and particularly between, those extension members 130b. The remaining sleeve 2 may optionally remain in place on the associated extension tab 136 for subsequent operation, thereby reducing the ingress of biological fluids into the associated channel 142 and thus providing a cleaner channel 142 for insertion therein of a subsequent member, such as a locking cap 170 for locking the spinal rod 180 within the fixation head 128, and for a separation tool to apply a predetermined twisting and / or pulling force to the frangible portion 140 to separate and remove the extension tab 136. In such an embodiment, a portion of the extension tab 136 may optionally remain within the sleeve 2 while the frangible portion 140 is broken, and the sleeve 2, extension tab 136, and separation tool may be removed from the patient in unison, if desired. In this manner, the sleeve 2 may be used to reduce friction and / or wear between the extension member 130 and associated instruments during a surgical procedure.

[0041] It should be understood that the sleeve 2 described herein may be used with other types of bone fixation procedures, or any procedure in which it is advantageous to provide a guide channel through soft tissue to a bone fixation device.

[0042] Although the present disclosure has been described in detail, it should be understood that various changes, substitutions, and alterations may be made herein without departing from the spirit and scope of the present invention, as defined by the appended claims. For example, features of various embodiments described herein may be incorporated into one or more, and up to all, of the other embodiments described herein. Furthermore, the scope of the present disclosure is not limited to the specific embodiments described herein. As one skilled in the art would readily appreciate from the process, any now-existing or later-developed machine, manufacture, composition of matter, means, method, or step that performs substantially the same function or achieves substantially the same result as the corresponding embodiment described herein may be utilized in accordance with the present disclosure.

[0043] [Embodiment] (1) A flexible tubular member for guiding the insertion of an instrument into a bone screw fixed in a bone, comprising: It is flexible, textile materials a tubular body constructed from: the tubular body defining a longitudinal axis and proximal and distal ends opposed to one another along the longitudinal axis, the tubular body defining a guide channel extending from a proximal opening at the proximal end to a distal opening at the distal end; an attachment member disposed at the distal end of the tubular body and configured to couple the distal end of the tubular body to a proximal portion of the bone screw, the attachment member defining an annular shape around the guide channel, the attachment member configured to expand in response to a predetermined tension applied to the tubular body to separate the tubular body from the bone screw. (2) A flexible tubular member as described in embodiment 1, wherein the tubular body is expandable along a radial direction perpendicular to the longitudinal axis while maintaining a substantially constant length along a longitudinal direction oriented along the longitudinal axis. (3) The above textile materials 3. The flexible tubular member of embodiment 2, wherein the flexible tubular member is one or more of woven, braided, knitted, and electrospun. (4) The flexible tubular member of embodiment 1, wherein the attachment member is defined by a material configured to be applied in a liquid or semi-liquid phase in an annular ring around the guide channel at the distal end and further configured to harden to a solid phase to define the attachment member. (5) The flexible tubular member of embodiment 1, wherein the attachment member is defined by a portion of the tubular body that is at least substantially melted into a ring annularly around the guide channel at the distal end and solidified to define the attachment member.

[0044] (6) The flexible tubular member of embodiment 1, further comprising an introduction member at the proximal end, the introduction member extending annularly around the guide channel and defining the proximal opening. (7) The flexible tubular member of embodiment 1, wherein the tubular body is configured to be flat when in a rest configuration when the guide channel is unoccupied. (8) The flexible tubular member of embodiment 1, wherein the tubular body defines a moisture barrier between the soft tissue and the guide channel. (9) The above textile materials 2. The flexible tubular member of claim 1, wherein the flexible tubular member is at least partially visible under magnetic resonance imaging (MRI). (10) A system for bone fixation, comprising: a bone screw having a head portion and a shaft extending distally from the head portion toward a distal end of the bone screw, the head portion defining a tapered portion narrowing in the distal direction; It is flexible, textile materialsa sleeve constructed from: the sleeve defining a longitudinal axis and proximal and distal ends opposed along the longitudinal axis, the sleeve defining a guide channel extending from a proximal opening at the proximal end to a distal opening at the distal end; a mounting ring disposed on the distal end of the sleeve and configured to couple the distal end of the sleeve to the tapered portion of the bone screw, the mounting ring extending annularly around the guide channel and configured to expand in response to a predetermined tension applied to the sleeve to separate the sleeve from the bone screw.

[0045] (11) The system of claim 10, further comprising a longitudinally elongated extension member configured to advance from the proximal opening in the distal direction through the guide channel and to couple to the head of the bone screw. (12) The extension member has a main portion, a fixed head portion defining a distal end of the extension member, and a weakened portion interposed between the main portion and the fixed head portion; the fixation head portion defines 1) a chamfered surface extending to the distal end of the extension member to facilitate advancement of the extension member through the guide channel, and 2) a receptacle portion configured to receive a head portion of the bone screw to couple the fixation head portion to the head portion of the bone screw; 12. The system of claim 11, wherein the weakened portion is configured to break in response to a predetermined force, thereby separating the main portion from the fixation head portion. (13) The fixed head portion an inner surface defining a bore extending along the longitudinally extending central bore axis, the inner surface defining the receptacle portion; a transverse channel extending along a transverse direction substantially perpendicular to the longitudinal direction, the transverse channel configured to receive a spinal rod; The system comprises: a retaining member configured to reside within the receptacle portion, the retaining member having an inner surface configured to engage the head portion of the bone screw and an outer surface configured to engage the inner surface of the fixation head portion in a manner to maintain a connection between the fixation head portion and the head portion of the bone screw; The system of embodiment 12, further comprising a locking cap configured to reside within the bore at the proximal end of the fixation head, the locking cap having a locking formation configured to engage with a complementary locking formation defined by the inner surface of the fixation head to lock the spinal rod within the transverse channel. (14) a first driver configured to engage a socket defined in the head portion of the bone screw to drive the bone screw into bone; 14. The system of claim 13, further comprising: a second driver configured to advance the extension member through the guide channel and couple the fixation head to the head of the bone screw, the second driver further configured to apply the predetermined force to the extension member to break the weakened portion and separate the main portion from the fixation head. (15) The system of embodiment 11, wherein the sleeve further comprises an introduction member at the proximal end, the introduction member extending annularly around the guide channel and defining the proximal opening, the introduction member defining an inner diameter greater than a maximum cross-sectional dimension of the extension member measured along a direction perpendicular to the longitudinal axis.

[0046] (16) A method for securing a bone screw to a bone, comprising: attaching a flexible sleeve to a head of a bone screw, whereby the sleeve extends proximally from the bone screw, the attaching step including advancing the bone screw through a guide channel defined by the sleeve until a distal surface of the head contacts a mounting ring at a distal end of the sleeve, the mounting ring defining an inner diameter less than a maximum diameter of the head; inserting a driver into a socket defined by the head portion of the bone screw, the driver being positioned within the guide channel of the sleeve while the driver is within the socket; advancing the bone screw through soft tissue to a fixation site in the bone; rotating the driver about a central axis, thereby threading the shaft of the bone screw into the fixation site, with the sleeve extending through the soft tissue and the proximal end of the sleeve disposed ex vivo; applying tension to the sleeve, thereby expanding the attachment ring to separate the sleeve from the bone screw. 17. The method of claim 16, further comprising, after threading the shaft into the fixation portion and before fracturing the attachment ring, inserting an extension member ex vivo through the proximal end of the sleeve and advancing the extension member distally through the guide channel until the head of the bone screw resides in a receptacle defined in a fixation head at the distal end of the extension member. 18. The method of claim 17, wherein the fixation head is configured to be polyaxially angled relative to the head of the bone screw. (19) Inserting a spinal rod into a channel defined by the fixation head, the channel extending from both sides of the fixation head along a direction substantially perpendicular to the central axis; The method of embodiment 17, further comprising advancing a locking member through the guide channel to the fixation head portion and connecting the locking member to a proximal portion of the fixation head portion, thereby attaching the spinal rod to the fixation head portion. (20) breaking a weakened portion of the extension member longitudinally disposed between the fixation head portion and a pair of extension tabs, wherein the extension tabs extend to a proximal end of the extension member, and the weakened portion is broken while at least a portion of the extension tabs are within the guide channel of the sleeve; 18. The method of claim 17, further comprising simultaneously removing the extension tab and the sleeve from the soft tissue.

Claims

1. A flexible tubular member for guiding the insertion of an instrument into a bone screw fixed in a bone, comprising: a tubular body that is flexible and constructed from a fibrous material, the tubular body defining a longitudinal axis and proximal and distal ends, the tubular body defining a guide channel that extends from a proximal opening at the proximal end to a distal opening at the distal end; an attachment member disposed at the distal end of the tubular body and configured to couple the distal end of the tubular body to a proximal portion of the bone screw, the attachment member defining an annular shape around the guide channel, the attachment member configured to expand in response to a predetermined tension applied to the tubular body to separate the tubular body from the bone screw.

2. 2. The flexible tubular member of claim 1, wherein the tubular body is expandable along a radial direction perpendicular to the longitudinal axis while maintaining a substantially constant length along a longitudinal direction oriented along the longitudinal axis.

3. The flexible tubular member of claim 2 , wherein the fibrous material is one or more of woven, braided, knitted, and electrospun.

4. The flexible tubular member of claim 1 , further comprising an introducer member at the proximal end, the introducer member extending annularly around the guide channel and defining the proximal opening.

5. The flexible tubular member of claim 1 , wherein the tubular body is configured to be flat when in a rest configuration when the guide channel is unoccupied.

6. The flexible tubular member of claim 1 , wherein the tubular body defines a moisture barrier between soft tissue and the guide channel.

7. The flexible tubular member of claim 1 , wherein the fiber material is at least partially visible under magnetic resonance imaging (MRI).

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