# US 11,998,255 B1 · Cannulated continuous compression screw > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,998,255 B1 - Document ID: US11998255B1 - Status: Granted - Kind: B1 - Application number: 18/375,483 - Filed: 2023-09-30 - Granted: 2024-06-04 - Earliest claimed: 2023-08-26 - Assignees: University of Utah Research Foundation - Applicants: University of Utah Research Foundation - Inventors: Colin S. Gregersen; T. Wade Fallin; Charles L. Saltzman; Chase Hagman - Web page: https://patentgrep.com/patent/US11998255B1 ## CPC - A61B 17/864: {hollow, e.g. with socket or cannulated} - A61B 17/8605: {Heads, i.e. proximal ends projecting from bone} - A61B 17/863: {with thread interrupted or changing its form along shank, other than constant taper} - A61B 17/8635: {Tips of screws} - A61B 17/866: {Material or manufacture} - A61B 17/8685: {comprising multiple separate parts} - A61B 2017/00867: {shape memory effect} - A61B 2017/564: {Methods for bone or joint treatment} - A61B 2017/681: {Alignment, compression, or distraction mechanisms} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A bone screw may be insertable into a bone. The bone screw may have a distal member with bone-engaging threads, a proximal member configured to slidably engage the distal member, and a tension member with a proximal end coupled to the proximal member, and a distal end coupled to the distal member such that, in response to motion of the distal member away from the proximal member, the tension member elongates and urges the distal member to move toward the proximal member. The tension member may be configured such that, at a minimum length of the bone screw, the tension member is pre-stretched so that the tension member is under tension to urge the bone screw to shorten. The bone screw may be inserted in the pre-stretched state. A pre-stretch driver may be used to tension the bone screw prior to or during insertion. ## Claims ### Claim 1 A bone screw insertable into a bone, the bone screw comprising: a distal member comprising bone-engaging threads; a proximal member configured to slidably engage the distal member; and a tension member comprising: a proximal end coupled to the proximal member; and a distal end coupled to the distal member such that, in response to motion of the distal member away from the proximal member, the tension member elongates and urges the distal member to move toward the proximal member; wherein: the proximal member comprises a head configured to resist insertion into the bone such that distal motion of the bone-engaging threads within the bone causes elongation of the tension member; wherein: the proximal member and the distal member define a longitudinal axis; the distal member comprises a distal engagement surface facing away from the longitudinal axis; the proximal member comprises a proximal engagement surface facing toward the longitudinal axis; and the distal engagement surface is positioned to abut the proximal engagement surface to transmit bending loads from the distal member to the proximal member without transmission of torque about the longitudinal axis between the distal engagement surface and the proximal engagement surface. ### Claim 2 (depends on 1) The bone screw of claim 1, wherein the tension member further comprises a shaft extending from the proximal end to the distal end, the shaft comprising a cannula sized to receive a guidewire. ### Claim 3 (depends on 1) The bone screw of claim 1, wherein: the bone screw has a length from a proximal-most end of the proximal member to a distal-most end of the distal member; and the proximal member and the distal member cooperate to define a length limiting mechanism configured to: prevent the length from exceeding a maximum length; and prevent the length from decreasing below a minimum length. ### Claim 4 (depends on 1) The bone screw of claim 1, wherein: the distal member and the proximal member cooperate to define a driver engagement feature configured to mate with a pre-stretch driver such that the pre-stretch driver is actuatable to urge the proximal member to move proximally relative to the distal member to cause elongation of the tension member independently of engagement of the bone screw with the bone; and the driver engagement feature comprises: a push feature on the distal member, configured to engage the pre-stretch driver in a manner that allows the push feature to be pushed distally by the pre-stretch driver; and a retention feature on the proximal member, configured to engage the pre-stretch driver in a manner that allows the retention feature to remain in place while the push feature advances distally. ### Claim 5 (depends on 4) The bone screw of claim 4, wherein: the push feature comprises a slot formed on a proximal surface of the distal member; and the retention feature comprises an internal groove formed on an interior surface of the proximal member. ### Claim 6 (depends on 5) The bone screw of claim 5, wherein the push feature is shaped to be rotatable by the pre-stretch driver to enable the pre-stretch driver to rotate the distal member independently of the proximal member during insertion of the bone screw into bone, causing the bone screw to elongate beyond a pre-stretch level induced by the pre-stretch driver. ### Claim 7 (depends on 6) The bone screw of claim 6, wherein the push feature comprises a slot shaped to receive a blade-shaped torque output feature of the pre-stretch driver. ### Claim 8 A system for providing compression within a bone, the system comprising: a bone screw comprising: a distal member comprising bone-engaging threads; a proximal member resiliently coupled to and configured to slidably engage the distal member; and a pre-stretch driver configured to urge elongation of the bone screw, the pre-stretch driver comprising: a sleeve configured to engage the proximal member; a driver shaft slidably retained within the sleeve, wherein the driver shaft is configured to engage the distal member; and an actuator configured to urge the driver shaft to move distally relative to the sleeve to urge the distal member to move distally relative to the proximal member. ### Claim 9 (depends on 8) The system of claim 8, wherein the bone screw further comprises a tension member comprising: a proximal end coupled to the proximal member; a distal end coupled to the distal member such that, in response to motion of the distal member away from the proximal member, the tension member elongates and urges the distal member to move toward the proximal member; and a shaft extending from the proximal end to the distal end, the shaft comprising a cannula sized to receive a guidewire. ### Claim 10 (depends on 8) The system of claim 8, wherein: the bone screw has a length from a proximal-most end of the proximal member to a distal-most end of the distal member; and the proximal member and the distal member cooperate to define a length limiting mechanism configured to: prevent the length from exceeding a maximum length; and prevent the length from decreasing below a minimum length. ### Claim 11 (depends on 8) The system of claim 8, wherein the proximal member and the distal member cooperate to define a driver engagement feature comprising: a push feature on the distal member, configured to engage the pre-stretch driver in a manner that allows the push feature to be pushed distally by the pre-stretch driver; and a retention feature on the proximal member, configured to engage the pre-stretch driver in a manner that allows the retention feature to remain in place while the push feature advances distally. ### Claim 12 (depends on 11) The system of claim 11, wherein: the push feature comprises a slot formed on a proximal surface of the distal member; and the retention feature comprises an internal groove formed on an interior surface of the proximal member. ### Claim 13 (depends on 12) The system of claim 12, wherein the push feature is shaped to be rotatable by the pre-stretch driver to enable the pre-stretch driver to rotate the distal member independently of the proximal member during insertion of the bone screw into bone, causing the bone screw to elongate beyond a pre-stretch level induced by the pre-stretch driver. ### Claim 14 (depends on 13) The system of claim 13, wherein: the pre-stretch driver further comprises a blade-shaped torque output feature; and the push feature comprises a slot shaped to receive the blade-shaped torque output feature. ### Claim 15 (depends on 8) The system of claim 8, wherein the pre-stretch driver further comprises a proximal end comprising a torque input feature that facilitates rotation of the pre-stretch driver, while coupled to the bone screw in a pre-stretched condition. ### Claim 16 (depends on 8) The system of claim 8, wherein: the actuator is configured to be rotated by hand to urge the distal member to move distally relative to the proximal member; and the pre-stretch driver further comprises a scale positioned to indicate a level of elongation of the bone screw by visual comparison of the scale with a position of the actuator. ### Claim 17 A method for inserting a bone screw into a bone, the method comprising: positioning the bone screw proximate the bone, the bone screw comprising: a distal member comprising bone-engaging threads; a proximal member configured to slidably engage the distal member; and a tension member coupled to the proximal member and the distal member such that, in response to motion of the distal member away from the proximal member, the tension member elongates and urges the distal member to move toward the proximal member; with the bone screw at a minimum length, stretching the tension member to move the tension member from a relaxed state to a stretched state; and with the tension member in the stretched state, inserting the bone screw into the bone. ### Claim 18 (depends on 17) The method of claim 17, wherein: the tension member further comprises a shaft extending from a proximal end to a distal end of the tension member, the shaft comprising a cannula; and inserting the bone screw into the bone comprises inserting the bone screw over a guidewire placed in the bone such that the cannula receives the guidewire. ### Claim 19 (depends on 17) The method of claim 17, further comprising, prior to positioning the bone screw proximate the bone: coupling the tension member to the proximal member and the distal member; and with the tension member coupled to the proximal member and the distal member and with the tension member at the minimum length, tensioning the tension member. ### Claim 20 (depends on 19) The method of claim 19, wherein: the bone screw further comprises a nut comprising interior threads; one of a proximal end and a distal end of the tension member comprises threads; and coupling the tension member to the proximal member and the distal member comprises engaging the interior threads of the nut with the threads of the tension member to couple the tension member to one of the proximal member and the distal member. ### Claim 21 (depends on 20) The method of claim 20, wherein: the threads are on the distal end of the tension member; coupling the tension member to the proximal member and the distal member further comprises, with the proximal member and the distal member at the minimum length, abutting a corresponding surface of the distal member with the nut; and tensioning the tension member comprises, with the bone screw at the minimum length, further actuating the nut after coupling the tension member to the distal member via the nut to pre-stretch the tension member.