阅读说明：本技术 脊柱畸形去旋转器械 (Spinal deformity rotation-removing instrument ) 是由 雅各布·帕克 于 2020-04-01 设计创作，主要内容包括：一种用于矫正脊柱畸形的外科器械(100),所述外壳器械(100)包括管状体(110),所述管状体(110)适于接收穿过所述管状体(110)的第二器械(200)。所述管状体(110)形成横向通道(126),所述横向通道(126)适于接收穿过所述管状体(110)的纵向固定元件。所述管状体(110)还包括用于将所述手术器械(100)连接到椎骨锚(300)的第一臂和第二臂(150,160)。所述第一臂和第二臂(150,160)包括一个或多个防张开特征,所述一个或多个防张开特征适于与所述第二器械(200)上的防张开特征配合,以在所述第二器械(200)插入所述管状体(110)中时防止所述第一臂和第二臂(150,160)张开。(A surgical instrument (100) for correcting a spinal deformity, the housing instrument (100) comprising a tubular body (110), the tubular body (110) being adapted to receive a second instrument (200) therethrough. The tubular body (110) forms a transverse channel (126), the transverse channel (126) being adapted to receive a longitudinal fixation element through the tubular body (110). The tubular body (110) further comprises first and second arms (150, 160) for connecting the surgical instrument (100) to a vertebral anchor (300). The first and second arms (150, 160) include one or more anti-deployment features adapted to mate with anti-deployment features on the second instrument (200) to prevent the first and second arms (150, 160) from deploying when the second instrument (200) is inserted into the tubular body (110).)

1. A surgical instrument (100) for correcting a spinal deformity, the surgical instrument (100) comprising a tubular body (110), the tubular body (110) having a proximal end (112), a distal end (114) opposite the proximal end (112), and a middle section (116) extending between the proximal end (112) and the distal end (114), the tubular body (110) defining a longitudinal axis (118) and a longitudinal channel (120) extending from the proximal end (118) to the distal end (114) along the longitudinal axis (118), the longitudinal channel (120) adapted to receive a second instrument (200) through the tubular body (110),

the tubular body (110) further defining a first longitudinal slot (122) and a second longitudinal slot (124) opposite the first longitudinal slot (122), the first longitudinal slot (122) and the second longitudinal slot (124) terminating at the distal end (114) of the tubular body (110) and forming a latitudinal channel (126) through the tubular body (110), the latitudinal channel (126) adapted to receive a longitudinal fixation element through the tubular body (110),

the tubular body (110) further comprising a first extension (132) and a second extension (134) opposite the first extension (132), the first extension (132) being separated from the second extension (134) by the first longitudinal slot (122) and the second longitudinal slot (124), the first extension (132) comprising a first pivot arm (150) for detachably connecting the surgical instrument (100) to a first connector on the vertebral anchor (300), and a second pivot arm (160) for detachably connecting the surgical instrument (100) to a second connector on the vertebral anchor (300), the first pivot arm (150) having a first activation end (152) and a first attachment end (154) opposite the first activation end (152), and the second pivot arm (160) having a second activation end (162) and a second attachment end (164) opposite the second activation end (162),

the first pivot arm (150) defines a first anti-splay slot (170) extending from the first activation end (152) to the first attachment end (154), the first anti-splay slot (170) being open to the longitudinal channel (120) and adapted to receive a first anti-splay element (250; 260) on the second instrument (200), and the second pivot arm (160) defines a second anti-splay slot (180) extending from the second activation end (162) to the second attachment end (164), the second anti-splay slot (180) being open to the longitudinal channel (120) and adapted to receive a second anti-splay element (250, 260) on the second instrument (200).

2. The surgical instrument (100) of claim 1, wherein the tubular body (110) defines a first elongate aperture (142) and a second elongate aperture (144), at least a portion of the first elongate aperture (142) extending into the first extension (132), at least a portion of the second elongate aperture extending into the second extension (134).

3. The surgical instrument (100) of claim 2, wherein the first pivot arm (150) is pivotally mounted in the first elongated aperture (142) and the second pivot arm (160) is pivotally mounted in the second elongated aperture (144), and/or wherein the first pivot arm (150) is mounted in the first elongated aperture (142) by a first pivot connection (147) and the second pivot arm (160) is mounted in the second elongated aperture (144) by a second pivot connection (148).

4. The surgical instrument (100) of any one of the preceding claims, wherein the first activation end (152) of the first pivot arm (150) is connected to the first attachment end (154) by a first dog leg segment (156) and the second activation end (162) of the second pivot arm (160) is connected to the second attachment end (164) by a second dog leg segment (166).

5. The surgical instrument (100) of claim 4, wherein the first anti-splay slot (170) defines a first hole (171) in the first dog leg segment (156) facing the proximal end (112) of the tubular body (110), the first hole (171) being configured to axially receive the first anti-splay element (250) on the second instrument (200), and wherein the second anti-splay slot (180) defines a second hole (181) in the second dog leg segment (166) facing the proximal end (112) of the tubular body (110), the second hole (181) being configured to axially receive the second anti-splay element (260) on the second instrument (200), and/or wherein the first pivot arm (150) is connected to the first pivot connection (147) at the first dog leg segment (156), and the second pivot arm (160) is connected to the second pivot connection (147) at the second dog leg segment (166) (148).

6. The surgical instrument (100) of any one of the preceding claims, wherein the first and second pivot arms (150, 160) are pivotally displaceable relative to the tubular body (110) between an attached position in which the first and second attachment ends (154, 164) are attachable to the vertebral anchor (300) and a released position in which the first and second attachment ends (154, 164) are removable from the vertebral anchor (300).

7. The surgical instrument (100) of claim 6, wherein the first activation end (152) of the first pivot arm (150) is closer to the longitudinal axis (118) in the release position than in the attachment position, and the second activation end (162) of the second pivot arm (160) is closer to the longitudinal axis (118) in the release position than in the attachment position.

8. The surgical instrument (100) of claim 6 or 7, further comprising a first biasing element biasing the first pivot arm (150) toward the attachment position and a second biasing element biasing the second pivot arm (160) toward the attachment position.

9. The surgical instrument (100) of claim 8, wherein the first biasing element comprises a first spring (153), the first spring (153) exerting a first radially outward biasing force (F) on the first activation end (152) of the first pivot arm (150)₁) And the second biasing element comprises a second spring (163), the second spring (163) exerting a second radially outward biasing force (F) on the second activation end (162) of the second pivot arm (160)₂)。

10. The surgical instrument (100) of claim 9, wherein the first and second pivot arms (150, 160) are configured to overcome the first radially outward biasing force (F) in response to radially inward forces applied to the first and second activation ends (152, 162) of the first and second pivot arms (150, 160), respectively₁) And said second radially outward biasing force (F)₂) And pivotally displaced towards the release position.

11. The surgical instrument (100) of claim 9 or 10, wherein pivotal displacement of the first and second pivot arms (150, 160) to the release position compresses the first and second springs (153, 163) under stored energy.

12. The surgical instrument (100) of claim 9, 10 or 11, wherein the first activation end (152) of the first pivot arm (150) includes a first groove (151) that receives the first spring (153), and the second activation end (162) of the second pivot arm (160) defines a second groove (161) that receives the second spring (163).

13. The surgical instrument (100) according to any one of the preceding claims 6 to 12, wherein the first activation end (152) of the first pivot arm (150) protrudes radially outward from the first hole (171) when the first pivot arm (150) is in the attached position and the second activation end (162) of the second pivot arm (160) protrudes radially outward from the second hole (181) when the second pivot arm (160) is in the attached position, and/or wherein the first hole (171) comprises a first stop for limiting the pivotal displacement of the first pivot arm (150) beyond the attached position and a second stop for limiting the pivotal displacement of the first pivot arm (150) beyond the released position.

14. The surgical instrument (100) of any one of the preceding claims 6 to 13, wherein the first attachment end (154) of the first pivot arm (150) extends into the longitudinal channel (120) when the first pivot arm (150) is displaced to the attachment position, and when the second pivot arm (160) is displaced to the attachment position, the second attachment end (164) of the second pivot arm (160) extends into the longitudinal channel (120), and/or wherein when the first pivot arm (150) is moved to the release position, the first attachment end (154) of the first pivot arm (150) is outside of the longitudinal channel (120), and when the second pivot arm (160) is moved to the release position, the second attachment end (164) of the second pivot arm (160) is outside of the longitudinal channel (120).

15. Surgical instrument (100) according to any one of the preceding claims, wherein the proximal end (112) of the tubular body (110) comprises a connecting element for axially guiding the second instrument (200) within the longitudinal channel (120).

Technical Field

The present disclosure relates generally to instruments for correcting spinal deformities, and more particularly to an instrument for performing de-rotation actions with other procedures.

Background

As disclosed in U.S. patent No. 7,454,939, spinal fixation systems may be used during surgery to align, adjust and/or fix portions of the spine, i.e., vertebrae, in a desired spatial relationship with respect to one another. Many spinal fixation systems employ spinal fixation rods to support the spine and properly position the spine of the spine for various therapeutic purposes. Spinal rods formed of metals such as cobalt chromium or titanium are commonly implanted to correct deformities, prevent movement of the vertebral bodies relative to each other, or for other purposes. Vertebral anchors include pins, bolts, screws, and hooks that engage the vertebrae and connect the rod to different vertebrae.

Adult Spinal Deformities (ASD) refer to a variety of spinal conditions in which the degree of curvature of the spine is outside of a defined normal range. In some patients, the deformities are measured at an angle of rotation relative to a particular plane (such as the sagittal plane). "Derotation" refers to surgery used to adjust rotation and correct abnormal spinal curvature. In a derotation procedure, one or more instruments are used to apply a bending moment to one or more vertebral anchors implanted in a vertebral body. The bending moment causes rotational and translational movement of the vertebral bodies relative to adjacent vertebral bodies. Each vertebral anchor is implanted deep within the incision, making it difficult to apply force directly to the anchor. Thus, bending moments are typically applied indirectly to the vertebral anchor by applying a derotation force to an elongate extension tube attached to the vertebral anchor extending over the incision.

In addition to applying a derotation force to the vertebral anchor, the extension tube may perform a variety of functions. For example, the extension tube can provide a hollow guide tube into which a second instrument can be inserted to access the vertebral anchor before or after de-rotation. Occasionally, insertion of a second instrument into the extension tube may create an outward force on the extension tube, causing the extension tube arms to deflect outward. This outward deflection (referred to herein as "splaying") can cause the extension tube arms to break away from the vertebral anchors and disrupt the surgical procedure.

Disclosure of Invention

A derotation instrument according to the present description provides a multi-functional extension tube that resists splaying when other instruments are inserted therein. These de-rotation instruments may include features that cooperatively engage with features on other instruments to prevent the attachment arms on the de-rotation instrument from splaying and disengaging from the vertebral anchors.

The derotation instrument according to the present description may be used not only to perform derotation actions, but also to position a fixation element (e.g., a spinal fixation rod) in a fixation element receiver and lock the fixation element receiver to a vertebral anchor. In addition, a derotation instrument according to the present description may provide access to allow other instruments to access vertebral anchors.

In one advantageous aspect of the present disclosure, an instrument for correcting a spinal deformity includes a surgical instrument for correcting a spinal deformity including a tubular body having a proximal end, a distal end opposite the proximal end, and a mid-section extending between the proximal and distal ends. The tubular body defines a longitudinal axis and a longitudinal channel extending along the longitudinal axis from the proximal end to the distal end, the longitudinal channel adapted to receive a second instrument therethrough.

In another advantageous aspect of the invention, the tubular body may further define a first longitudinal groove and a second longitudinal groove opposite the first longitudinal groove. The first and second longitudinal grooves may terminate at the distal end of the tubular body and form a transverse passageway through the tubular body. The transverse channels may be adapted to receive longitudinal fixation elements through the tubular body.

In another beneficial aspect of the present disclosure, the tubular body can further include a first extension and a second extension opposite the first extension. The first extension is separated from the second extension by a first longitudinal slot and a second longitudinal slot. The first extension can include a first pivot arm for detachably connecting a surgical instrument to a first connector on a vertebral anchor and a second pivot arm for detachably connecting a surgical instrument to a second connector on the vertebral anchor. The first pivot arm may include a first activation end and a first attachment end opposite the first activation end, and the second pivot arm may include a second activation end and a second attachment end opposite the second activation end.

In another beneficial aspect of the present disclosure, the first pivot arm can define a first anti-splay slot extending from the first activation end to the first attachment end. The first anti-splay channel may be open to the longitudinal channel and adapted to receive a first anti-splay member on a second instrument. The second pivot arm may define a second anti-stretch slot extending from the second activation end to the second attachment end. The second anti-splay channel may be open to the longitudinal channel and adapted to receive a second anti-splay member on a second instrument.

In another beneficial aspect of the present disclosure, the tubular body may define a first elongated aperture, at least a portion of which extends into the first extension, and a second elongated aperture, at least a portion of which extends into the second extension.

In another advantageous aspect of the invention, the first pivot arm is pivotally mounted in the first elongated aperture and the second pivot arm is pivotally mounted in the second elongated aperture.

In another beneficial aspect of the present disclosure, the first pivot arm may be mounted in the first elongated aperture via a first pivot connection and the second pivot arm may be mounted in the second elongated aperture via a second pivot connection.

In another beneficial aspect of the present disclosure, the first activation end of the first pivot arm may be connected to the first attachment end by a first dog leg segment, and the second activation end of the second pivot arm may be connected to the second attachment end by a second dog leg segment.

In another beneficial aspect of the present disclosure, the first anti-splay slot may define a first aperture in the first dog leg segment facing the proximal end of the tubular body, the first aperture configured to axially receive a first anti-splay element on the second instrument.

In another beneficial aspect of the present disclosure, the second anti-splay channel may define a second aperture in the second dog leg segment facing the proximal end of the tubular body, the second aperture configured to axially receive a second anti-splay element on a second instrument.

In another beneficial aspect of the present disclosure, the first pivot arm can be connected to the first pivot connection at the first dogleg section and the second pivot arm can be connected to the second pivot connection at the second dogleg section.

In another beneficial aspect of the present disclosure, the first and second pivot arms are pivotally displaceable relative to the tubular body between an attachment position in which the first and second attachment ends are attachable to the vertebral anchor and a release position in which the first and second attachment ends are removable from the vertebral anchor.

In another beneficial aspect of the present disclosure, the first activation end of the first pivot arm is closer to the longitudinal axis in the release position than in the attachment position, and the second activation end of the second pivot arm is closer to the longitudinal axis in the release position than in the attachment position.

In another beneficial aspect of the present disclosure, the first biasing element may bias the first pivot arm toward the attachment position and the second biasing element may bias the second pivot arm toward the attachment position.

In another advantageous aspect of the present disclosure, the first biasing element may include a first spring exerting a first radially outward biasing force on the first actuating end of the first pivot arm, and the second biasing element may include a second spring exerting a second radially outward biasing force on the second actuating end of the second pivot arm.

In another beneficial aspect of the present disclosure, the first and second pivot arms are configured to overcome the first and second radially outward biasing forces and pivotally displace toward the release position in response to radially inward forces applied to the first and second actuation ends of the first and second pivot arms, respectively.

In another beneficial aspect of the present disclosure, the pivotal displacement of the first and second pivot arms to the release position may compress the first and second springs under stored energy.

In another advantageous aspect of the present disclosure, the first actuating end of the first pivot arm may include a first groove that receives the first spring, and the second actuating end of the second pivot arm may define a second groove that receives the second spring.

In another advantageous aspect of the present invention, the first activation end of the first pivot arm can project radially outward from the first aperture when the first pivot arm is in the attached position, and the second activation end of the second pivot arm can project radially outward from the second aperture when the second pivot arm is in the attached position.

In another advantageous aspect of the present disclosure, the first aperture may include a first stop for limiting pivotal displacement of the first pivot arm beyond the attachment position and a second stop for limiting pivotal displacement of the first pivot arm beyond the release position.

In another advantageous aspect of the invention, the first attachment end of the first pivot arm may extend into the longitudinal channel when the first pivot arm is displaced to the attachment position, and the second attachment end of the second pivot arm may extend into the longitudinal channel when the second pivot arm is displaced to the attachment position.

In another beneficial aspect of the present disclosure, the first attachment end of the first pivot arm may be outside of the longitudinal channel when the first pivot arm is moved to the release position and the second attachment end of the second pivot arm may be outside of the longitudinal channel when the second pivot arm is moved to the release position.

In another advantageous aspect of the present disclosure, the proximal end of the tubular body may include a coupling element for axially guiding a second instrument within the longitudinal channel.

Drawings

The foregoing summary, as well as the following detailed description, will be better understood when read in conjunction with the non-limiting examples illustrated in the accompanying drawings, wherein:

FIG. 1 is a perspective view of a derotation instrument according to one embodiment;

FIG. 2 is a side view of the derotation instrument of FIG. 1 shown in partial cross section;

FIG. 2A is an enlarged view of a region of the derotation instrument of FIG. 2;

FIG. 3 is an exploded perspective view of the derotation instrument of FIG. 1;

FIG. 4 is an enlarged, truncated side view of a distal segment of one of the components of the de-rotation instrument of FIG. 1;

FIG. 5 is a side view of the derotation instrument of FIG. 1 in a first operating condition;

FIG. 6 is a side view of the derotation instrument of FIG. 1 in a second operational condition;

FIG. 7 is a perspective view of the derotation instrument of FIG. 1 and a separate insert pusher instrument usable with the derotation instrument;

FIG. 8 is an exploded perspective view of a vertebral anchor that may be used with the derotation instrument of FIG. 1;

FIG. 9 is an enlarged view of the distal end of the insert pusher instrument of FIG. 7 and the vertebral anchor of FIG. 8, with a portion of the vertebral anchor having been cut away;

FIG. 10 is a side view of the insert pusher instrument of FIG. 7;

FIG. 11 is another side view of the insert pusher instrument of FIG. 7 shown in partial cross-section; and

fig. 11A is an enlarged view of a region of the insert pusher instrument shown in fig. 11.

Detailed Description

Referring to fig. 1 and 2, a derotation instrument 100 is shown according to one embodiment. The derotation instrument 100 is configured to be removably coupled to a vertebral anchor implanted in a vertebral body to perform corrective adjustments to the spine and subsequently secure a fixation element to the vertebral anchor. For example, the rotation instrument 100 can be operated to induce a bending moment in the vertebral anchors to adjust the curvature of the spine. This can be accomplished by attaching the derotation instrument 100 to the vertebral anchor and manually applying the derotation force. The surgeon may manually apply the derotation force directly to the derotation instrument or indirectly to the derotation instrument through another instrument or attachment attached to the derotation instrument. The derotation force is transmitted to the vertebral body through the derotation instrument and the vertebral anchor. As used herein, the term "de-rotational force" refers to a force manually applied by a spinal surgeon or other user that induces a bending moment in the vertebral bodies to correct abnormal curvature of the spine. As used herein, the term "force applying instrument" refers to an instrument configured to apply a derotating force, which may be the derotating instrument itself, or an instrument or attachment attached to the derotating instrument. The force applying instrument may also be configured to perform other functions before, during, and/or after the application of the derotation force.

As will be explained, the derotation instrument 100 may be used with another instrument to temporarily lock the rod receiver to the bone screw. The de-rotation instrument 100 may also be used with a rod inducer instrument to perform rod inducement. In addition, the derotation instrument 100 can be used as a portal that allows other instruments to access the vertebral anchor to which the derotation instrument is attached. In some applications, the derotation instrument 100 may be operated in conjunction with one or more other derotation instruments attached to other vertebral bodies in the spine.

The derotation instrument 100 includes a tubular body 110 having a proximal end 112, a distal end 114 opposite the proximal end, and a middle section 116 extending between the proximal and distal ends. The tubular body 110 defines a longitudinal axis 118 and a longitudinal channel 120 extending along the longitudinal axis. The longitudinal channel 120 extends from the proximal end 112 to the distal end 114 of the tubular body 110.

The tubular body 110 defines a first longitudinal slot 122 and a second longitudinal slot 124 opposite the first longitudinal slot. The first longitudinal slot 122 and the second longitudinal slot 124 terminate at the distal end 114 of the tubular body 110 and form a transverse passageway 126 through the tubular body. The transverse channel 126 is adapted to receive a longitudinal fixation element, such as a spinal fixation rod, through the tubular body. The derotation instrument 100 can be used with the help of other instruments to insert the longitudinal fixation element into the vertebral anchor, position the longitudinal fixation element in the vertebral anchor, and fix the longitudinal fixation element in the vertebral anchor with the locking element.

The tubular body 110 also includes a first extension 132 and a second extension 134 opposite the first extension. The first and second extensions 132, 134 merge with the middle section 116 of the tubular body 110 and have a free end 137 that terminates at the distal end 114. The first extension 132 is separated from the second extension 134 by the first longitudinal slot 122 and the second longitudinal slot 124.

The first and second extensions according to the present disclosure are configured to detachably connect to a vertebral anchor. For example, first and second extensions according to the present disclosure may be configured to detachably connect to a rod receiver or "tulip" member associated with a vertebral anchor. In this regard, the first and second extensions can have an internal geometry adapted to conform to the external geometry of the vertebral anchor. For example, the extension can be an arcuate extension having a concave inner surface that conforms to a circular outer geometry associated with a rod receiver or tulip member of a vertebral anchor. In this example, the first extension 132 and the second extension 134 each form a partial cylinder with a concave inner surface 133, the concave inner surface 133 conforming to the circular outer geometry of the rod receiver of the vertebral anchor. In this configuration, the first extension 132 and the second extension 134 are configured to receive the rod receiver therebetween and to clamp securely onto the rod receiver.

The first and second extensions 132, 134 include a coupling mechanism 140, the coupling mechanism 140 being configured to lock and unlock the clamping engagement between the first and second extensions and the vertebral anchor. The coupling mechanism 140 includes a first pivot arm 150 for detachably coupling the first extension 132 to a first connector on a vertebral anchor. The coupling mechanism 140 further includes a second pivot arm 160 for detachably connecting the second extension 134 to a second connector on the vertebral anchor. Pivot arms according to the present disclosure may be mounted to the tubular body in a variety of arrangements. In the present example, the tubular body 110 defines a first elongated aperture 142 and a second elongated aperture 144, with a portion of the first elongated aperture 142 extending into the first extension 132 and a portion of the second elongated aperture 144 extending into the second extension 134. The first pivot arm 150 is pivotally mounted in the first elongated aperture 142 and the second pivot arm 160 is pivotally mounted in the second elongated aperture 144. In particular, the first pivot arm 150 is configured to pivot about the first pivot axis 143 through the first elongated aperture 142 and the second pivot arm 160 is configured to pivot about the second pivot axis 145 through the second elongated aperture 144. The first pivot axis 143 and the second pivot axis 145 are parallel to each other and perpendicular to the longitudinal axis 118 of the tubular body 110.

Referring to fig. 3, additional details of the derotation instrument 100 and its components are shown. The first pivot arm 150 has a first activation end 152 and a first attachment end 154 opposite the first activation end. Similarly, the second pivot arm 160 has a second activation end 162 and a second attachment end 164 opposite the second activation end. The first pivot arm 150 is mounted in the first elongated aperture 142 by a first pivot connection in the form of a pin 147 passing through the first elongated aperture. The second pivot arm 160 is mounted in the second elongated aperture 144 by a second pivot connection in the form of a pin 148 passing through the second elongated aperture.

The first activation end 152 of the first pivot arm 150 is connected to the first attachment end 154 by a first dog leg segment 156. The second activation end 162 of the second pivot arm 160 is connected to the second attachment end 164 by a second dog leg segment 166. The first dog leg segment 156 defines a through hole 157, the through hole 157 adapted to receive the pin 147 to mount the first pivot arm 150 in the first elongated aperture 142. The second dog leg segment 166 defines a through hole 167, the through hole 167 adapted to receive the pin 148 to mount the second pivot arm 160 in the second elongated aperture 152. In this arrangement, the first and second pivot arms 150 and 160 may pivot about pins 147 and 148, respectively. That is, the first and second pivot arms 150 and 160 are retained in the first and second elongated apertures 142 and 152, respectively, but are pivotally displaceable within the first and second elongated apertures.

The first and second pivot arms 150 and 160 are independently pivotable relative to the tubular body 110 between an attached position and a released position. In the attachment position shown in fig. 5, the first and second pivot arms 150 and 160 are positioned such that the first and second attachment ends 154 and 164 are pivoted inward toward the longitudinal axis 118 of each pivot arm in which the vertebral anchor can engage. As will be explained, the first attachment end 154 and the second attachment end 164 engage the vertebral anchor in a form-locking manner to connect the derotation instrument 100 to the vertebral anchor. In the release position shown in fig. 6, the first and second attachment ends 154, 164 are pivoted outward and away from the longitudinal axis 118 to allow the derotation instrument 100 to be separated from the vertebral anchor. As will be appreciated from fig. 5 and 6, the first attachment end 154 and the second attachment end 164 are closer to the longitudinal axis 118 in the connected position than in the released position. Conversely, the first and second activation ends 152, 162 are closer to the longitudinal axis 118 in the release position than in the connection position.

A derotation instrument according to the present disclosure may be configured with one or more biasing mechanisms that maintain the attachment between the attachment end and the vertebral anchor until the biasing mechanism is released or overcome by some counter force. In this example, derotation instrument 100 includes a first biasing element that biases first pivot arm 150 toward the attached position and a second biasing element that biases second pivot arm 160 toward the attached position. Various types of biasing mechanisms may be used, including, but not limited to, leaf springs, wave springs, torsion springs, coil springs, spring washers, and other biasing elements that store and release energy when a force is applied and removed.

The first pivot arm 150 defines a circular blind hole or groove 151, the blind hole or groove 151 receiving a biasing element in the form of a first spring 153. Similarly, the second pivot arm 160 defines a circular blind hole or recess 161, the blind hole or recess 161 receiving a biasing element in the form of a second spring 163. The first and second springs 153, 163 are wave springs configured to store energy in response to an axial compressive force and release energy when the axial compressive force is removed.

Fig. 2A provides an enlarged view of the first spring 153 assembled within the groove 151 of the first pivot arm 150. The first spring 153 has a first end 155, the first end 155 abutting a wall in the form of a washer 157 secured inside the tubular body 110. The first spring 153 also has a second end 158, the second end 158 abutting an inner surface or spring seat 159 within the groove 151. As shown, the axial length LS of the first spring 153 is greater than the axial depth DR of the groove 151 such that the first spring protrudes outside the groove in a relaxed or uncompressed state.

The second spring 163 is assembled with the second pivot arm 160 in the same arrangement and manner as the first spring 153 is assembled with the first pivot arm 150. Thus, the arrangement of the second spring 163 in the second pivot arm 160 is the same as the first spring 153 in the first pivot arm 150 shown in fig. 2A. Like the first spring 153, the second spring 163 has a first end 165, the first end 165 abutting a wall in the form of a washer 167 secured inside the tubular body 110. The second spring 163 also has a second end 168, the second end 168 abutting an inner surface or spring seat 169 within the recess 161. The axial length of the second spring 163 is greater than the axial depth of the groove 161 so that the second spring protrudes outside the groove in a relaxed or uncompressed state.

Referring to fig. 1, the first spring 153 is configured to exert a first radially outward biasing force F1 on the first activation end 152 of the first pivot arm 150. The second spring 163 is configured to exert a second radially outward biasing force F2 on the second activation end 162 of the second pivot arm 160. The biasing force F1 is directed in a first radially outward direction and the biasing force F2 is directed in a second radially outward direction opposite the first radially outward direction. The first activation end 152 and the second activation end 162 are diametrically opposed to each other relative to the longitudinal axis 118 such that the biasing forces F1, F2 have the effect of urging the first attachment end 154 and the second attachment end 164 toward each other, i.e., toward their respective attachment positions.

The first and second pivot arms 150, 160 are pivotally displaceable against biasing forces F1, F2, respectively, to displace the first and second actuation ends 152, 162 toward their respective release positions. That is, the first activation end 152 may be pivotally displaced inwardly toward the longitudinal axis 118 in response to a first inwardly directed force applied to the first activation end. Likewise, the second actuation end 162 may be pivotally displaced inwardly toward the longitudinal axis 118 in response to a second inwardly directed force applied thereto, wherein the direction of such force is more or less opposite to the direction of the first inwardly directed force. The spacing between the first and second actuation ends 152, 162 is small, allowing a user to manually compress or squeeze the first and second actuation ends together by pressing their thumb against one of the actuation ends and their forefinger against the other of the actuation ends.

The first and second attachment ends according to the present disclosure can have various configurations for attachment to a vertebral anchor. For example, the first and second pivot arms can have one or more engagement structures designed to mate with one or more complementary engagement structures on the vertebral anchor. These engagement structures may take the form of bosses, pins, tabs or other regularly or irregularly shaped protrusions, with or without a spring-biased mechanism, that releasably engage holes, slots, cutouts or other regularly or irregularly shaped voids. It should be understood that any such protrusion may be formed on the pivot arm and any such void may be formed on the vertebral anchor and vice versa.

Referring to fig. 3 and 4, the first and second attachment ends 154, 164 have engagement structures in the form of first and second locking tabs 172, 182, respectively. The first and second locking tabs 172, 182 are identically configured and are arranged in a mirror image arrangement, as are other features of the first and second pivot arms 150, 160. For the sake of brevity, only the details of the first locking tab 172 will be described, it being understood that the same description applies to the second locking tab 182.

The first locking tab 172 has an irregularly shaped tab body 173 that projects radially inward from the abutment section 150a of the first pivot arm 150. The adjoining section 150a of the first pivot arm 150 has a constant width section 150b that transitions into a tapered end section 150 c. The tapered end section 150c has two linear sides 150d that transition to a rounded end 150 e. Tab body 173 has a proximal end 174, a distal end 175, and a mid-section 176 between the proximal and distal ends. The middle section 176 includes a constant width narrow section 176a that is narrower than the width of the constant width section 150b of the adjoining section 150 a. The narrow section 176a transitions into a widened section 176b, the width of the widened section 176b being the same as the width of the constant width section 150b of the adjoining section 150 a. The widened section 176b transitions into a narrower neck 176c having a width that is narrower than the width of the constant width section 150b of the adjoining section 150 a. Finally, neck 176c transitions into rounded end 176d, a portion of its perimeter abutting rounded end 150e of abutting section 150 a.

Tab 173 is configured to be inserted into a first cutout in the outer sidewall of the rod receiver of the vertebral anchor. The cutout is adapted to receive the tab 173 in a keyed arrangement when the first pivot arm 150 is pivoted towards the longitudinal axis 118 to the attachment position. The shape of the cutout may be the same as some or all of the above-described segments of the tab body 173. In either case, the shape of the cutout may have narrowed and widened sections to fit around narrow section 176a, widened section 176b, neck 176c, and/or end 176d in a shape-locking manner. Once the tab 173 is pivoted into the cut-out to assume the attachment position, the outer wall of the tab abuts the inner wall of the cut-out in a form-locking engagement to prevent the tab from moving in the cut-out in any direction other than outward in response to pivotal displacement of the first pivot arm 150 towards the release position.

The vertebral anchor can have a second cutout adapted to receive the second locking tab 182 of the second pivot arm 160 in the same arrangement and manner as described above with respect to the first locking tab 172.

The first and second pivot arms 150, 160 are thus responsible for locking the derotation instrument 100 to the vertebral anchor.

Referring now to FIG. 7, the de-rotation instrument 100 is shown having a second instrument in the form of an insert pusher instrument or "insert pusher" 200. The primary purpose of insert pusher 200 is to temporarily lock the position of the rod receiver relative to the position of the bone screws on the vertebral anchors without inserting the rod and locking screws (e.g., set screws) into the vertebral anchors. This is done as a temporary locking procedure that inhibits polyaxial rotation of the rod receiver about the bone screw (referred to as "polyaxial locking"). Once polyaxial locking is performed, the bone screw and the rod receiver may form a single fixation structure, allowing an adjustment force to be simultaneously applied to the rod receiver and the bone screw.

Fig. 8 and 9 illustrate one example of a vertebral anchor 300 that may be used with a derotation instrument and insert pusher according to the present disclosure. The vertebral anchor 300 includes a polyaxial bone screw 310 having a spherical screw head 312 and a threaded shank 314. The bone screw 310 is configured to be received in the rod receiver 320. The rod receiver 320 has an upper portion 322, the upper portion 322 defining a U-shaped channel 323 to receive an elongated fixation element, such as a spinal rod. The stem receiver 320 also has a lower portion 324 that defines a spherical seat 326 and a through bore 328 therein. The diameter of the through hole 328 is smaller than the diameter of the screw head 312. Thus, the rod receiver 320 is configured to receive the bone screw 320 in a seated arrangement with the screw head 312 seated in the spherical seat 326 and the threaded rod 314 protruding from the through-hole 328.

The stem receiver 320 has a pair of diametrically opposed cutouts 321, the cutouts 321 opening out of the stem receiver and extending into the walls of the stem receiver. The cutout 321 has an irregular shape that conforms to the irregular shape of the locking tabs 172, 182 on the derotation instrument 100.

Vertebral anchor 300 further includes an insert 330. The insert 330 has an upper portion 332 that defines a U-shaped recess 334 to receive an elongated fixation element, such as a spinal rod. The insert 330 also has a lower portion 336, the lower portion 336 having a spherical recess 338. When the vertebral anchor 300 is assembled, the insert 330 is positioned in the rod receiver 320 adjacent to the screw head 312. In this position, the groove 334 is positioned to receive an elongated fixation element, such as a spinal rod, and the recess 338 is positioned against and in frictional engagement with the screw head 312.

Fig. 9 shows a cross-sectional view of insert pusher 200 in vertebral anchor 300 and engaged with insert 330. The insert pusher 200 is operable to lock the position of the rod receiver 320 by applying an axial force on the insert 330. To this end, the insert pusher 200 has four pusher posts 236 that engage a platform 331 on top of the insert 330. The axial force on the platform 331 compresses the insert into frictional engagement with the screw head 312 of the bone screw 310. The frictional engagement is sufficient to stabilize the rod receiver 320 on the screw head 312 such that the rod receiver does not pivot or "jump" on the bone screw 310.

Once the rod receiver and the polyaxial screw are polyaxially locked, a derotation force may be applied to the vertebral anchor using a derotation instrument. Polyaxial locking of the vertebral anchor is helpful, but not necessary, when a derotation force is applied. Thus, it is contemplated that the derotation instrument 100 may be used to apply derotation forces on the vertebral anchor 300 without polyaxial locking and without inserting the advancer 200 into position.

When de-rotation is performed with the insert pusher 200 in place, the de-rotation force applied to the de-rotation instrument 100 is transferred to the multi-axial locking rod receiver 320 and the bone screw 310 to adjust the position of the vertebral body.

The features of the insert pusher 200 are shown in more detail in fig. 10-11A. Insert pusher 200 includes a tubular body 210, with tubular body 210 having a proximal end 212, a distal end 214 opposite the proximal end, and a mid-section 216 extending between the proximal and distal ends. The tubular body 210 defines a longitudinal axis 218 and a longitudinal channel 220 extending along the longitudinal axis. Longitudinal passageway 220 extends from proximal end 212 to distal end 214 of tubular body 210.

The tubular body 210 defines a first longitudinal slot 222 and a second longitudinal slot 224 opposite the first longitudinal slot. First longitudinal slot 222 and second longitudinal slot 224 terminate at distal end 214 of tubular body 210 and form a transverse passageway 226 through the tubular body. Like the transverse channel 126 of the derotation instrument 100, the transverse channel 226 is adapted to receive a longitudinal fixation element, such as a spinal fixation rod, through the tubular body. The tubular body 210 further includes a first extension 232 and a second extension 234 opposite the first extension. The first extension 232 is separated from the second extension 234 by the first longitudinal slot 222 and the second longitudinal slot 224. In addition, first and second extensions 232, 234 merge with the middle section 216 of the tubular body and terminate at the distal end 214. Each of the first and second extensions 232, 234 has a pair of push posts 236. As described above, the push post 236 is configured to apply an axial force to the insert in the vertebral anchor to lock the position and orientation of the rod receiver relative to the bone screw.

Proximal end 212 of insert pusher 200 has a connector ring 221, and connector ring 221 is configured to couple insert pusher 200 to the interior of derotation instrument 100. Connector ring 221 is also operable to axially move the insert pusher within the de-rotation instrument and maintain the insert pusher in coaxial alignment with the de-rotation instrument. Connector ring 221 is connected to middle section 216 of insert pusher 200 by rotatable coupling 223. Referring to fig. 11A, rotatable coupling 223 includes a snap ring 225, which snap ring 225 is partially received in an annular groove 227 within connector ring 221 and partially received in circumferential groove 217 in middle section 216. In this arrangement, the connector ring 221 is rotatable relative to the intermediate section 216 and the distal end 214 of the insert pusher 200, but is axially fixed thereto.

Connector ring 221 has a toothed surface 222, which toothed surface 222 is configured to engage a similar toothed surface of another instrument that may be coupled to the connector ring to apply torque to insert pusher 220. Connector ring 221 also has male threads 229 extending around its circumference. The male threads 229 are configured to mate with female threads 129 (shown in fig. 2 and 3) within the proximal end 112 of the derotation instrument 100. When male thread 229 is mated with female thread 129, insert pusher 200 is axially displaced and guided within longitudinal channel 120 in response to rotation of connector ring 221. The engagement between the male thread 229 and the female thread 129 maintains the insert pusher 200 in coaxial alignment with the derotation instrument 100. This alignment, as well as the pre-aligned placement of the pushing post 236 and the insert in the polyaxial screw, ensures that the pushing post contacts the appropriate portion of the insert to apply axial force and lock the rod receiver onto the pedicle screw.

An insert pusher and de-rotation instrument according to the present disclosure may have one or more mechanisms that prevent the first and second pivot arms from opening when the instruments are combined. If not prevented, the splaying may cause the first and second pivot arms to disconnect from the vertebral anchor and interrupt the surgical procedure.

The term "splay-proof" as used herein refers to any feature that maintains the first and second pivot arms in their locked positions and prevents the locking arm from splaying. An anti-splay mechanism according to the present disclosure prevents splaying of the first and second pivot arms on the derotation instrument while the insert pusher is advanced into the derotation tube and engages the vertebral anchor to apply the polyaxial locking force. In this example, the middle section 216 of the insert pusher 200 has a first pair of anti-splay elements in the form of locking rails 250. In addition, the first and second extensions 232, 234 have a second pair of anti-deployment elements in the form of locking tracks 260 that are axially aligned with the locking tracks 250. Locking track 260 is axially longer than locking track 250.

Each locking track 250, 260 has a T-shaped body 270, the T-shaped body 270 including a stem portion 272 extending outwardly from the body 210 and a flange portion 274 extending generally perpendicular to the stem portion 272. Referring again to fig. 3, the first pivot arm 150 defines a first anti-splay slot 170 extending from the first dog leg segment 156 to the first attachment end 154. Similarly, the second pivot arm 160 defines a second anti-tension slot 180 extending from the second dog leg segment 166 to the second attachment end 164. The first and second anti-stretch slots 170, 180 are adapted to axially receive the first and second locking rails 250, 260 through their proximal ends and allow the locking rails to slide axially to the distal ends of the pivot arms 150, 160. In particular, first anti-splay slot 170 defines a first aperture 171 in first dog leg segment 156 facing proximal end 212 of body 210. The second anti-stretch slot 180 similarly defines a second aperture 181 in the second dog leg segment 166 facing the proximal end 212 of the barrel 210. The first and second holes 171, 181 are each configured to axially receive the first and second locking rails 250, 260 to allow the locking rails to slide axially to the distal ends of the pivot arms 150, 160.

The first anti-stretch slot 170 and the second anti-stretch slot 180 define respective openings 170A, 180A that open to the longitudinal channel 120. The openings 170A, 180A receive the stems 272 of the locking rails 250, 260 when the locking rails are inserted into the pivot arms 150, 160. The locking tracks 250, 260 are positioned axially on the insert pusher 200 such that when the insert pusher is advanced as far as possible into the longitudinal channel 120 to engage the insert 330 of the vertebral anchor, the locking tracks prevent the distal ends of the pivoting arms 150, 160 from splaying or bending outward. This maintains pivot arms 150, 160 in a straight configuration with locking tabs 172, 182 securely fixed in cut-outs 321 of lever receiver 320.

The derotation instrument 100 and the insert pusher 200 may be operated in the following manner to adjust or correct the curvature of the spine. The described mode of operation assumes that the vertebral anchor is the aforementioned vertebral anchor 300 or similar polyaxial screw assembly. However, it should be understood that the derotation instrument 100 and the insert pusher 200 may be used with other types of vertebral anchors. After the vertebral anchor 300 is implanted in the vertebral body, the derotation instrument 100 is attached to the rod receiver 320 by lowering the free end 137 about the rod receiver such that the rod receiver is received into the longitudinal channel 120 between the first extension 132 and the second extension 134. The derotation instrument 100 is also oriented relative to the rod receiver 320 such that the first locking tab 172 and the second locking tab 182 are aligned with the cut-outs 321 in the outside of the rod receiver 320. Once the first and second locking tabs 172, 182 are properly aligned with the cut-outs 321, the de-rotation instrument 100 is axially advanced over the rod receiver 320 until the rod receiver is sandwiched between the first and second extensions 132, 134.

The derotation instrument 100 may be in gripping engagement with the rod receiver 320 in a variety of ways. In a first locking method, de-rotation instrument 100 is advanced over shaft receiver 320 with first pivot arm 150 and second pivot arm 160 in the attached position. That is, no force is applied to either the first activation end 152 or the second activation end 162. In this case, as shown in fig. 5, the first attachment end 154 and the second attachment end 164 are closer together, protruding into the longitudinal channel 120. As the derotation instrument 100 is advanced over the rod receiver 320, the locking tabs 172, 182 slide axially into the notches 321 and lockingly engage the rod receiver.

In a second locking method, de-rotation instrument 100 is advanced over shaft receiver 320 while first pivot arm 150 and second pivot arm 160 are moved to a release position. That is, as shown in fig. 6, a radially inward compressive force is applied to the first and second activation ends 152, 162 to spread the first and second attachment ends 154, 164 farther apart. When the first pivot arm 150 is in the attached position, the first activation end 152 protrudes radially outward from the first elongated aperture 142. The second activation end 162 of the second pivot arm 160 projects radially outward from the second elongated aperture 144 when the second pivot arm is in the attached position.

The pivotal displacement of the first and second pivot arms 150, 160 to the release position compresses the first and second springs 153, 163 under the stored energy and moves the first and second attachment ends 154, 164 outside of the longitudinal channel 120. In this state, the derotation instrument 100 may be fully advanced on the rod receiver, which may be determined by the tactile sensation when stop surfaces on the derotation instrument and the rod receiver contact each other, or by other means. Once the derotation instrument 100 is fully advanced over the rod receiver, the inward compression forces on the first and second activation ends 152, 162 are removed. This releases the pressure on the first and second springs 153, 163, allowing the springs to expand and urge the first and second actuating ends 152, 162 radially outward. This, in turn, causes the first attachment end 154 and the second attachment end 164 to pivot radially inward such that the first and locking tabs 172 and the second locking tab 182 enter their corresponding cutouts 321 in the stem receiver 320. Once the first attachment end 154 and the second attachment end 164 are pivoted in this manner, the first attachment end and the second attachment end assume their respective attachment positions in the cutout 321 to lock the derotation instrument 100 to the rod receiver 320.

The de-rotation instrument according to the present invention may further comprise one or more features to limit the pivotal movement of the first and second pivot arms when the insert pusher is not inserted in the pivot arm. This may be desirable to control the position of the activation end and the attachment end after pivoting and limit the amount of force applied to the spring. For example, a derotation instrument according to the present disclosure may have one or more stop elements that limit the range of pivotal movement of the pivot arm. In the present example, the first and second elongated apertures 142, 144 each have a proximal stop 192 and a distal stop 194 along each side. The first and second pivot arms 150 and 160 have proximal and distal stop surfaces 196 and 198. The proximal stop surface 196 is configured to abut the proximal stop 192 when the first and second pivot arms 150, 160 are pivoted to the release position. This limits the deflection of the springs 153, 163 and limits the outward displacement of the first attachment end 154 and the second attachment end 164. The distal stop surface 198 is configured to abut the distal stop 194 when the first and second pivot arms 150, 160 are pivoted to the attached position. This limits inward displacement of the first and second attachment ends 154, 164 and limits outward displacement of the first and second activation ends 152, 162 out of their respective elongated apertures 142, 144.

Once the derotation instrument 100 is attached to the vertebral anchor, the derotation instrument can receive a force applying instrument for applying a polyaxial locking tightening force to the vertebral anchor. For example, the insert pusher 200 may be inserted into the derotation instrument 100 by axially aligning the tubular body 210 with the longitudinal channel 120. Prior to advancing the insert pusher 200 into the rotation instrument 100, the insert pusher must be oriented in the correct orientation such that the rails 250, 260 are axially aligned with the first and second force-transmitting slots 170, 180, respectively. To this end, the derotation instrument 100 and the insert pusher 200 have an orientation mechanism 280, the orientation mechanism 280 maintaining the insert pusher in the proper orientation as the insert pusher is inserted and advanced into the longitudinal channel 120 of the derotation instrument.

Instruments according to the present disclosure may feature many different types of orientation mechanisms, including but not limited to unique geometric features on the mating surfaces. In the present example, as shown in FIG. 11, the orientation mechanism 280 includes a pair of diametrically opposed longitudinal rods 281 extending along the tubular body 210. Longitudinal rod 281 is offset at a 90 degree angle from track 250. The orientation mechanism 280 further includes a pair of diametrically opposed longitudinal channels 101 extending into the inner wall of the tubular body 110. A portion of one channel 101 is shown in fig. 3 on one side of the tubular body 110, it being understood that the same longitudinal channel extends in the inner wall of the opposite side of the tubular body. The insert pusher 200 can be inserted and advanced in the longitudinal channel 120 of the derotation instrument 100 only when the longitudinal rod 281 is axially aligned with the longitudinal channel 101. The width of each longitudinal channel 101 is slightly wider than the width of each longitudinal rod 281. Accordingly, longitudinal channel 101 is adapted to receive longitudinal rod 281 in a restrained orientation that prevents insert pusher 200 from rotating relative to de-rotation instrument 100 when longitudinal rod 281 is inserted into de-rotation instrument 100. This ensures that the rails 150, 160 remain axially aligned with the first anti-splay slot 170 and the second anti-splay slot 180 during insertion of the insert pusher 200.

Although the description makes reference to particular embodiments and illustrations, the invention is not intended to be limited to the details shown. For example, it should be understood that a derotation instrument according to the present disclosure need not work exclusively with an insert pusher, but may be used with other types of instruments that do not have an insert pusher in place. For example, a derotation instrument according to the present disclosure may be configured to work with a rod inducer instrument. In such an assembly, the rod inducer instrument can include a locking track arranged to cooperate with the pivoting arms of the de-rotation instrument in the same manner as the locking tracks 250, 260 described on the inserter pusher 200.

Thus, the present disclosure encompasses various modifications and combinations of the specific embodiments described herein and illustrated, including variations that may be made within the scope of the equivalents of the claims as initially filed.

According to a first aspect, the present invention is directed to a surgical instrument 100 for correcting a spinal deformity, the surgical instrument 100 including a tubular body 110, the tubular body 110 having a proximal end 112, a distal end 114 opposite the proximal end 112, and a middle section 116 extending between the proximal end 112 and the distal end 114, the tubular body 110 defining a longitudinal axis 118 and a longitudinal channel 120 extending along the longitudinal axis 118 from the proximal end 112 to the distal end 114, the longitudinal channel 120 adapted to receive a second instrument 200 through the tubular body 110, the tubular body 110 further defining a first longitudinal slot 122 and a second longitudinal slot 124 opposite the first longitudinal slot 122, the first and second longitudinal slots 122, 124 terminating at the distal end 114 of the tubular body 110 and forming a transverse channel 126 through the tubular body 110, the transverse channel 126 adapted to receive a longitudinal fixation element through the tubular body 110, the tubular body 110 further including a first extension 132 and a second extension 134 opposite the first extension 132, the first extension 132 is separated from the second extension 134 by a first longitudinal slot 122 and a second longitudinal slot 124, the first extension 132 including a first pivot arm 150 for detachably connecting the surgical instrument 100 to a first connector on the vertebral anchor 300, and a second pivot arm 160 for detachably connecting the surgical instrument 100 to a second connector on the vertebral anchor 300, the first pivot arm 150 having a first activation end 152 and a first attachment end 154 opposite the first activation end 152, the second pivot arm 160 having a second activation end 162 and a second attachment end 164 opposite the second activation end 162, the first pivot arm 150 defining a first anti-splay slot 170 extending from the first activation end 152 to the first attachment end 154, the first anti-splay slot 170 being open to the longitudinal channel 120 and adapted to receive a first anti-splay element 250 on the second instrument 200; 260 and the second pivot arm 160 defines a second anti-splay slot 180 extending from the second activation end 162 to the second attachment end 164, the second anti-splay slot 180 being open to the longitudinal channel 120 and adapted to receive a second anti-splay element 250, 260 on the second instrument 200.

According to a second aspect of the present invention, the surgical instrument 100 according to the first aspect is further characterized in that the tubular body 110 defines a first elongated aperture 142 and a second elongated aperture 144, at least a portion of the first elongated aperture 142 extending into the first extension 132, and at least a portion of the second elongated aperture 144 extending into the second extension 134.

According to a third aspect of the present invention, the surgical instrument 100 according to the second aspect is further characterized in that the first pivot arm 150 is pivotally mounted in the first elongated aperture 142 and the second pivot arm 160 is pivotally mounted in the second elongated aperture 144.

According to a fourth aspect of the present invention, the surgical instrument 100 according to the second or third aspect is further characterized in that the first pivot arm 150 is mounted in the first elongated aperture 142 by a first pivot connection 147 and the second pivot arm 160 is mounted in the second elongated aperture 144 by a second pivot connection 148.

According to a fifth aspect of the present invention, the surgical instrument 100 according to one of the previous aspects is further characterized in that the first activation end 152 of the first pivot arm 150 is connected to the first attachment end 154 by a first dog leg segment 156 and the second activation end 162 of the second pivot arm 160 is connected to the second attachment end 164 by a second dog leg segment 166.

According to a sixth aspect of the present invention, the surgical instrument 100 according to the fifth aspect is further characterized in that the first anti-splay slit 170 defines a first hole 171 in the first dog leg segment 156 facing the proximal end 112 of the tubular body 110, the first hole 171 being configured to axially receive a first anti-splay element 250 on the second instrument 200, and wherein the second anti-splay slit 180 defines a second hole 181 in the second dog leg segment 166 facing the proximal end 112 of the tubular body 110, the second hole 181 being configured to axially receive a second anti-splay element 260 on the second instrument 200.

According to a seventh aspect of the present invention, the surgical instrument 100 according to the fifth or sixth aspect is further characterized in that the first pivot arm 150 is connected to the first pivot connection 147 at a first dog leg section 156 and the second pivot arm 160 is connected to the second pivot connection 148 at a second dog leg section 166.

According to an eighth aspect of the present invention, the surgical instrument 100 according to one of the previous aspects is further characterized in that the first and second pivot arms 150, 160 are pivotally displaceable relative to the tubular body 110 between an attachment position in which the first and second attachment ends 154, 164 are attachable to the vertebral anchor 300, and a release position in which the first and second attachment ends 154, 164 are removable from the vertebral anchor 300.

According to a ninth aspect of the present invention, the surgical instrument 100 according to the eighth aspect is further characterized in that the first activation end 152 of the first pivot arm 150 is closer to the longitudinal axis 118 in the release position than in the attachment position, and the second activation end 162 of the second pivot arm 160 is closer to the longitudinal axis 118 in the release position than in the attachment position.

According to a tenth aspect of the present invention, the surgical instrument 100 according to the eighth or ninth aspect is further characterized by a first biasing element that biases the first pivot arm 150 toward the attachment position and a second biasing element that biases the second pivot arm 160 toward the attachment position.

According to an eleventh aspect of the present invention, the surgical instrument 100 according to the tenth aspect is further characterized in that the first biasing element comprises a first spring 153, the first spring 153 exerting a first radially outward biasing force F on the first activation end 152 of the first pivot arm 150₁And the second biasing element comprises a second spring 163, the second spring 163 exerting a second radially outward biasing force F on the second actuating end 162 of the second pivot arm 160₂。

According to a twelfth aspect of the present invention, the surgical instrument 100 according to the eleventh aspect is further characterized in that the first and second pivot arms 150 and 160 are configured to overcome the first radially outward biasing force F in response to radially inward forces applied to the first and second activation ends 152 and 162 of the first and second pivot arms 150 and 160, respectively₁And a second radially outward biasing force F₂And pivotally displaced towards the release position.

According to a thirteenth aspect of the present invention, the surgical instrument 100 according to the eleventh or twelfth aspect is further characterized in that the pivotal displacement of the first and second pivot arms 150, 160 to the release position compresses the first and second springs 153, 163 under stored energy.

According to a fourteenth aspect of the present invention, the surgical instrument 100 according to the eleventh, twelfth or thirteenth aspect is further characterized in that the first activation end 152 of the first pivot arm 150 includes a first groove 151 that receives the first spring 153, and the second activation end 162 of the second pivot arm 160 defines a second groove 161 that receives the second spring 163.

According to a fifteenth aspect of the present invention, the surgical instrument 100 according to the eighth, ninth, tenth, eleventh, twelfth, thirteenth or fourteenth aspect is further characterized in that the first activation end 152 of the first pivot arm 150 protrudes radially outward from the first hole 171 when the first pivot arm 150 is in the attached position, and the second activation end 162 of the second pivot arm 160 protrudes radially outward from the second hole 181 when the second pivot arm 160 is in the attached position.

According to a sixteenth aspect of the present invention, the surgical instrument 100 according to the eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth or fifteenth aspect is further characterized in that the first aperture 171 comprises a first stop for limiting the pivotal displacement of the first pivot arm 150 beyond the attachment position and a second stop for limiting the pivotal displacement of the first pivot arm 150 beyond the release position.

According to a seventeenth aspect of the present invention, the surgical instrument 100 according to the eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth or sixteenth aspect is further characterized in that the first attachment end 154 of the first pivot arm 150 extends into the longitudinal channel 120 when the first pivot arm 150 is displaced to the attachment position, and the second attachment end 164 of the second pivot arm 160 extends into the longitudinal channel 120 when the second pivot arm 160 is displaced to the attachment position.

According to an eighteenth aspect of the present invention, the surgical instrument 100 according to the eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, sixteenth or seventeenth aspect is further characterized in that the first attachment end 154 of the first pivot arm 150 is outside the longitudinal channel 120 when the first pivot arm 150 is displaced to the release position, and the second attachment end 164 of the second pivot arm 160 is outside the longitudinal channel 120 when the second pivot arm 160 is displaced to the release position.

According to a nineteenth aspect of the present invention, the surgical instrument 100 according to one of the preceding aspects is further characterized in that the proximal end 112 of the tubular body 110 includes a connecting element for axially guiding the second instrument 200 within the longitudinal channel 120.