CORRECTIVE APPLIANCE

To provide a corrective appliance capable of properly assisting in correction of spinal deformity by a spinal deformity correction and fusion system while limiting damage on a rod member when the spinal deformity is subjected to correction and fusion by the spinal deformity correction and fusion system. A corrective appliance includes: a clamp member to be attached detachably to a screw member, for example, and to be arranged close to the screw member; and an auxiliary rod member to be attached detachably to the clamp member and to be used for correcting spinal deformity. This allows the corrective appliance to properly assist in correction of spinal deformity by a spinal deformity correction and fusion system while limiting damage on a rod member when the spinal deformity is subjected to correction and fusion by the spinal deformity correction and fusion system.

TECHNICAL FIELD

The present invention relates to a corrective appliance for assisting in correction and fusion during implementation of spinal deformity correction and fusion surgery in which spinal deformity is subjected to the correction and fusion by a spinal deformity correction and fusion system including a vertebra fixing tool to be fixed to each of a plurality of vertebrae and a rod member to be coupled to the vertebra fixing tool.

BACKGROUND ART

In a normal condition of a spine, the spine is generally straight when viewed from the back, cervical vertebrae and lumbar vertebrae curve forward and thoracic vertebrae and sacral vertebrae curve backward when viewed from the side. In this way, the spine shows an approximately S-shaped appearance. Spinal deformity causing abnormality at the spine is a disease with the deformed spine, and includes scoliosis, kyphosis, and kyphoscoliosis, for example. Scoliosis is a disease in which the spine is twisted while being curved laterally. Kyphosis is a disease in which the angle of thoracic kyphosis becomes extremely large, or lumbar lordosis is lost to be deformed toward kyphosis. Kyphoscoliosis is a disease caused by a combination of scoliosis and kyphosis.

For treatment of such types of spinal deformity, spinal deformity correction and fusion surgery is widely conducted. The spinal deformity correction and fusion surgery is an operation for correcting a deformed spine to a normal state or a state close to the normal state and then fixing the corrected spine using a spinal deformity correction and fusion system (self-contained member, which is what is called an implant) described later. Posterior correction and fusion surgery or anterior correction and fusion surgery is employed for such operation. In particular, the posterior correction and fusion surgery is conducted as follows. For implementation of the posterior correction and fusion surgery, a patient is positioned on an operating table in a prone position. Then, an operative wound or a percutaneous surgical wound using minimally invasive technique is placed along the median line of the patient's back, and posterior elements of the spine are unfolded. Subsequently, a spinal deformity correction and fusion system described later (see patent literature 1, for example) is mounted on the spine to three-dimensionally correct the spinal deformity. The spine is fixed in this state.

Generally, a system to be employed as the spinal deformity correction and fusion system includes: a plurality of screw members each to be screwed into a vertebral body through a pedicle of each vertebra of a spine; a hook member to be hooked on a pedicle, a vertebral arch, or a transverse process, for example, of each vertebra; rod members in a pair to be coupled to a top-opened groove of each screw and that of each hook member, extending along an axis direction of the spine, and arranged at an interval in a crosswise direction of a patient, etc.

For example, when a patient with scoliosis is subjected to posterior correction and fusion surgery conducted to correction and fusion of spinal deformity by mounting the above-described spinal deformity correction and fusion system on a spine, the screw member and the hook member are first fixed to each of a plurality of vertebrae to be corrected. Next, the rod member is engaged with the top-opened groove of the screw member and that of the hook member. At this time, the rod member extends linearly while the spine is deformed to make it quite difficult to engage the rod member with the top-opened groove of the screw member and that of hook member. In response to this, an operator uses a dedicated surgical instrument to give a curve to the rod member along the scoliosis deformity of the spine. Then, the curved rod is engaged with the top-opened groove of the screw member and that of the hook member fixed to each vertebra. Then, in order to prevent the rod member from coming off the top-opened groove of each screw member and that of each hook member, set screws are temporarily tightened in these top-opened grooves.

Next, the outer peripheral surface of the rod member is sandwiched with a dedicated surgical instrument corresponding to a pair of pliers and this surgical instrument is rotated about 90° to rotate the rod member about 90° about its axis. In this way, operation of correcting the scoliosis deformity including twisting of the spine is performed. Operation of correcting the scoliosis deformity of the spine is also performed by applying compressive load or tensile load between members such as a plurality of screw members arranged in the axis direction (cranio-caudal direction) of the spine and screw members arranged adjacent to each other in the axis direction of the spine, for example, using a dedicated surgical instrument. After implementation of such operation for the correction, the set screws are fully tightened to form firm coupling of the rod member with each screw member and each hook member, thereby correcting and fixing the spine.

CITATION LIST

Patent Literatures

Patent Literature 1: Japanese Patent Application Publication No. 2012-213625

SUMMARY OF INVENTION

Problem to be Solved by Invention

According to the conventional correction and fusion method using the spinal deformity correction and fusion system, the rod member is engaged with the top-opened groove of each screw member and that of each hook member while being curved along the scoliosis deformity of the patient. As the spine is under the scoliosis deformity including twisting, however, it becomes quite difficult to engage the rod member, even in the curved state, with the top-opened groove of each screw member and that of the hook member. Additionally, as a range of the correction and fusion using the spinal deformity correction and fusion system becomes longer, it becomes more difficult to engage the rod member with the top-opened groove of each screw member and that of the hook member.

According to the conventional correction and fusion method using the spinal deformity correction and fusion system, operation of correcting the scoliosis deformity including twisting of the spine is performed by sandwiching the outer peripheral surface of the rod member firmly with a dedicated surgical instrument corresponding to a pair of pliers (such as a rod gripper) and by rotating the rod member about 90°. If the rod member curved along the scoliosis deformity of the patient is rotated about 90° about its axis, however, this curvature of the rod member is replaced with backward curvature and forward curvature of the patient. However, as this curvature of the rod member does not conform to the physiological backward curvature and forward curvature of the patient, another trouble might be caused.

Furthermore, according to the conventional correction and fusion method using the spinal deformity correction and fusion system, the outer peripheral surface of the rod member is sandwiched firmly with a dedicated surgical instrument corresponding to a pair of pliers and is rotated 90°. This causes a risk of damage on the outer peripheral surface of the rod member at positions sandwiched with the surgical instrument corresponding to a pair of pliers. Additionally, as the set screws are temporarily tightened in the top-opened groove of each screw member and that of each hook member, rotating the rod member also causes a risk of damage on the outer peripheral surface of the rod member at positions of contact with the set screw. As a result, many of such damaged positions become causes for breakage of the rod member after indwelling inside a body.

The present invention has been made in view of the foregoing issues, and is intended to provide a corrective appliance capable of properly assisting in correction of spinal deformity by a spinal deformity correction and fusion system while limiting damage on a rod member when the spinal deformity is subjected to the correction and fusion by the spinal deformity correction and fusion system.

Means of Solving Problem

The aspects of the invention described below exemplify the configuration of the present invention, and are described separately by items in order to facilitate the understanding of various configurations of the present invention. Each item does not limit the technical scope of the present invention. While the best mode for carrying out the invention is taken into consideration, partial replacement and deletion of some of the components in each item, or further addition of other configurations should be included in the technical scope of the present invention.

(1) A corrective appliance is used for assisting in correction and fusion when spinal deformity is subjected to the correction and fusion by a spinal deformity correction and fusion system including a vertebra fixing tool to be fixed to each vertebrae of a spine and a rod member to be coupled to the vertebra fixing tool. The corrective appliance includes: a clamp member to be attached detachably to the vertebra fixing tool and to be arranged close to the vertebra fixing tool; and a corrective member to be attached detachably to the clamp member and to be used for correcting the spinal deformity (corresponding to the invention recited in Claim1).

When the spinal deformity is subjected to the correction and fusion by the spinal deformity correction and fusion system, the corrective appliance described in the item (1) is capable of assisting in the correction using the clamp member and the corrective member. Specifically, after the vertebra fixing tool is fixed to each vertebra, the clamp member is attached to each vertebra fixing tool and the corrective member is attached further to each clamp member. Next, the corrective member is operated to correct the spinal deformity properly though each clamp member and each vertebra fixing tool and the corrected state is retained. Next, the rod member is coupled to each vertebra fixing tool to fix a spine in the corrected state. Then, the corrective member and each clamp member are detached from each vertebra fixing tool and taken out of a body. During the correction and fusion of the spinal deformity in this way by the spinal deformity correction and fusion system, unlike in the conventional case, it is not necessary to engage the rod member of the spinal deformity correction and fusion system with each vertebra fixing tool fixed to each vertebra under scoliosis deformity including twisting, or to perform operation of giving a curve to the rod member of the spinal deformity correction and fusion system using a dedicated surgical instrument or operation of firmly sandwiching the rod member and rotating (turning) the rod member using a dedicated surgical instrument. As a result, it becomes possible to limit damage on the rod member as a self-contained member. Furthermore, using the corrective appliance allows the rod member of the spinal deformity correction and fusion system to be easily engaged with (coupled to) each vertebra fixing tool. As a result, correction of the spinal deformity becomes easier to facilitate implementation of a surgery itself, thereby contributing to reduction in a duration of the surgery.

The corrective appliance described in the item (1) is used effectively, particularly if the correction and fusion by the spinal deformity correction and fusion system covers a long range. Specifically, if the range of the correction and fusion by the spinal deformity correction and fusion system is long, the clamp member is attached selectively to the vertebra fixing tool fixed to each vertebra, the corrective member is attached to each clamp member, a deformed spine is corrected partially, and the corrected state is retained using these clamp member and corrective member. Then, the rod member is coupled to each vertebra fixing tool. By doing so, the spine can be fixed in the corrected state.

(2) The corrective appliance described in the item (1) is characterized in that the clamp member includes a groove, and the corrective member is an auxiliary rod member configured to be engaged with the groove of the clamp member (corresponding to the invention recited in Claim2).

In the corrective appliance described in the item (2), the auxiliary rod member can be given a curve along scoliosis deformity and can be engaged with the groove of each clamp member fixed to each vertebra, instead of the rod member of the spinal deformity correction and fusion system (self-contained member). The auxiliary rod member can be used for correcting spinal deformity through the clamp member and the vertebra fixing tool. Then, the correction using the corrective appliance is completed and the correction is retained. In this state, the rod member as the self-contained member is coupled to each vertebra fixing tool, thereby allowing retention of the corrected state of the spinal deformity by the spinal deformity correction and fusion system. As a result, it becomes possible to limit damage on the rod member as the self-contained member, thereby reducing the occurrence of breakage of the rod member easily after the rod member indwells in a body.

(3) The corrective appliance described in the item (1) or (2) is characterized in that the clamp member includes supporting pieces in a pair movable closer to and farther from each other to support a head of the vertebra fixing tool in such a manner as to sandwich the head (corresponding to the invention recited in Claim3).

In the corrective appliance described in the item (3), the clamp member can be attached to support the head of the vertebra fixing tool in such a manner as to sandwich the head using the supporting pieces in a pair of the clamp member. Furthermore, a top-opened groove provided at the top face of the head of the vertebra fixing tool and used for engagement with the rod member can be exposed to the outside. As a result, after correction of spinal deformity and retention of the corrected state using the clamp member and the corrective member, the rod member can be engaged easily with the top-opened groove of each vertebra fixing tool. Furthermore, the vertebra fixing tool can be supported firmly from opposite lateral sides of the head using the supporting pieces in a pair of the clamp member. Thus, force of the correction applied from the clamp member can be transmitted properly to a vertebra through the vertebra fixing tool, making it possible to correct the spinal deformity properly.

(4) The corrective appliance described in the item (1) or (2) is characterized in that the clamp member includes a ring-like member to support a head of the vertebra fixing tool in such a manner as to surround an outer periphery of the head (corresponding to the invention recited in Claim4).

In the corrective appliance described in the item (4), the clamp member can be attached to support the head of the vertebra fixing tool in such a manner as to surround the outer periphery of the head using the ring-like member of the clamp member. This allows the head entirely of the vertebra fixing tool to be supported firmly using the ring-like member of the clamp member. Thus, force of the correction applied from the clamp member can be transmitted properly to a vertebra through the vertebra fixing tool, making it possible to correct spinal deformity properly.

(5) The corrective appliance described in any one of the items (2) to (4) is characterized in that the clamp member includes a fixing tool for fixing the auxiliary rod member to the groove of the clamp member (corresponding to the invention recited in Claim5).

In the corrective appliance described in the item (5), by operating the auxiliary rod member while the auxiliary rod member is temporarily tightened to the groove of each clamp member using the fixing tool, it becomes possible to correct spinal deformity easily through each clamp member. The auxiliary rod member is fixed firmly to the groove of each clamp member using the fixing tool. By doing so, the spinal deformity can be retained in the corrected state using the clamp member and the auxiliary rod member.

(6) The corrective appliance described in the item (4) or (5) is characterized in that the clamp member includes stopper pawl sections in a pair for sandwiching the head of the vertebra fixing tool (corresponding to the invention recited in Claim6).

In the corrective appliance described in the item (6), the stopper pawl sections in a pair can be used for fixing the clamp member to the vertebra fixing tool firmly. As a result, force of the correction applied from the clamp member can be transmitted properly to a vertebra through the vertebra fixing tool, making it possible to correct spinal deformity properly.

(7) The corrective appliance described in any one of the items (1) to (6) is characterized in that the corrective appliance is configured as a surgical instrument detachable from the vertebra fixing tool to be taken out of a body while the spinal deformity is corrected and fixed by the spinal deformity correction and fusion system (corresponding to the invention recited in Claim7).

As the corrective appliance described in the item (7) functions as a surgical instrument, it is not required to be made of a material having excellent biocompatibility such as titanium alloy or cobalt-chromium alloy. This imposes no limitation on a material to be used, leading to cost reduction.

(8) The corrective appliance described in any one of the items (2) to (7) is characterized in that the auxiliary rod member has an outer diameter same as that of the rod member.

The corrective appliance described in the item (8) can entirely be given a compact configuration.

(9) The corrective appliance described in any one of the items (6) to (8) is characterized in that the head of the vertebra fixing tool is provided with concaved sections for supporting tips of the stopper pawl sections.

In the corrective appliance described in the item (9), the stopper pawl sections of the clamp member are engaged with the concaved sections at the vertebra fixing tool. This makes it possible to minimize backlash of the clamp member relative to the vertebra fixing tool occurring during attachment of the clamp member to the vertebra fixing tool.

Advantageous Effects of Invention

The corrective appliance according to the present invention is capable of properly assisting in correction of spinal deformity by a spinal deformity correction and fusion system while limiting damage on a rod member when the spinal deformity is subjected to correction and fusion by the spinal deformity correction and fusion system.

DESCRIPTION OF EMBODIMENTS

Embodiments for carrying out the present invention will be described below in detail on the basis ofFIGS. 1 to 14.

A corrective appliance1A according to a first embodiment of the present invention will be described first in detail on the basis ofFIGS. 1 to 8.

The corrective appliance1A according to the first embodiment of the present invention is to assist in correction and fusion when spinal deformity is subjected to the correction and fusion by a spinal deformity correction and fusion system2(seeFIG. 8(f)). The spinal deformity correction and fusion system2briefly includes: a plurality of screw members3(seeFIGS. 1 and 2) each to be screwed into a vertebral body through a pedicle of each vertebra of a spine; a plurality of hook members4(seeFIG. 3) each to be hooked on a pedicle, a vertebral arch, or a transverse process, for example, of each vertebra; and a rod member5(seeFIG. 1) to be coupled to a groove10of each screw member3and to a groove24of each hook member4and extending along an axis direction of a spine. These screw members3and hook members4correspond to a vertebra fixing tool. The spinal deformity correction and fusion system2further includes another constituting member such as a connector member (not shown in the drawings) provided to bridge the rod members5,5in a pair. A plurality of the screw members3and the rod members5,5in a pair of the spinal deformity correction and fusion system2are shown inFIG. 8(f).

The screw member3, the hook member4, and the rod member5are made of a material of excellent biocompatibility such as titanium alloy. As shown inFIG. 1, the rod member5is formed into a circular shape in a section. The length of the rod member5is set appropriately in response to a degree of spinal deformity of a patient. As shown inFIGS. 1 and 2, the screw member3is to be screwed into a vertebral body through a pedicle of each vertebra from the back of a spine. The screw member3is generally called a pedicle screw. The screw member3includes a rod receiving section11(head) with a groove10to receive the rod member5, and a screw portion12coupled to the rod receiving section11and to be screwed into a vertebral body through a pedicle of a vertebra.

The rod receiving section11is formed into a block-like shape in a plan view with planar portions15,15in a pair and arc-like portions16,16in a pair. The rod receiving section11is provided with the U-shape groove10opened on the opposite side of the screw portion12and extending in an axis direction of the rod member5. The groove10is formed in such a manner as to penetrate the planar portions15,15in a pair. The groove10is configured to receive the rod member5. The rod receiving section11has walls with inner wall surfaces facing each other across the groove10at which corresponding female threads17,17are formed. A set screw20is screwed into the female threads17,17. The planar portions15,15of the rod receiving section11are provided with concaved sections22,22in a pair formed at positions close to the respective tops of the planar portions15,15. The arc-like portions16,16of the rod receiving section11have outer peripheral surfaces where engagement grooves23,23extending in a peripheral direction are formed at positions close to the respective tops of the arc-like portions16,16. The screw portion12is coupled to the rod receiving section11in such a manner as to be swingable relative to the rod receiving section11in a direction in which the groove10extends. A range of the swinging motion of the screw portion12relative to the rod receiving section11is within 25° from the center to each side (a total swinging range of about 50°).

As shown inFIG. 3, the hook member4is to be engaged with a vertebra by being hooked on a pedicle, a vertebral arch, or a transverse process, for example, of the vertebra from the back of a spine. The hook member4includes a rod receiving section25(head) with a groove24to receive the rod member5, and a hook portion26integrally connected to the rod receiving section25. The rod receiving section25is formed into a block-like shape in a plan view with planar portions30,30in a pair and arc-like portions31,31in a pair. The rod receiving section25is provided with the U-shape groove24opened on the opposite side of the hook portion26and extending in the axis direction of the rod member5. The groove24is formed in such a manner as to penetrate the planar portions30,30in a pair. The U-shape groove24is configured to receive the rod member5.

The rod receiving section25has walls with inner wall surfaces facing each other across the groove24at which corresponding female threads32,32are formed. A set screw35is screwed into the female threads32,32. The planar portions30of the rod receiving section25are provided with concaved sections37,37in a pair formed at positions close to the respective tops of the planar portions30. The arc-like portions31,31of the rod receiving section25have outer peripheral surfaces where engagement grooves38,38extending in a peripheral direction are formed at positions close to the respective tops of the arc-like portions31,31. In some cases, the hook member4includes a sandwiching part39arranged in such a manner as to face the hook portion26and to be movable in an axis direction. The sandwiching part39and the hook portion26can be used for firmly sandwiching a transverse process, etc.

A corrective appliance1A according to the first embodiment of the present invention will be described next in detail on the basis ofFIGS. 1 and 4 to 6. For the convenience of description, the following explanation is given on the assumption that, inFIGS. 1 and 4 to 6, the screw portion12of the screw member3shown inFIG. 1is on a lower side and the rod receiving section11of the screw member3is on an upper side (on the opposite side of the screw portion12). The corrective appliance1A according to the first embodiment of the present invention functions as a surgical instrument to be taken out of a body after spinal deformity is subjected to correction and fusion by the spinal deformity correction and fusion system2(seeFIG. 8(f)). As shown inFIG. 1, the corrective appliance1A according to the first embodiment includes a clamp member50A to be attached detachably to the rod receiving section11(head) of the screw member3and to be arranged close to the rod receiving section11of the screw member3, and an auxiliary rod member51as a corrective member to be attached detachably to the clamp member50A and to be used for correcting spinal deformity.

As shown inFIG. 1, in the present embodiment, the clamp member50A of the corrective appliance1A according to the first embodiment is attached to the rod receiving section11of the screw member3. The clamp member50A is also attachable to and detachable from the rod receiving section25of the hook member4shown inFIG. 3. The auxiliary rod member51is formed into a circular shape in a section. The auxiliary rod member51has an outer diameter substantially the same as that of the rod member5of the spinal deformity correction and fusion system2.

As shown inFIGS. 1 and 4 to 6, the clamp member50A used in the corrective appliance1A according to the first embodiment includes: a screw support54with supporting pieces111,111in a pair spaced apart from each other to support the rod receiving section11of the screw member3; a rod receiving section55with a U-shape groove63with an opened upper surface; a first gear56arranged in the rod receiving section55, a second gear57in meshing engagement with the first gear56extending from the interior of the screw support54to the interior of the rod receiving section55; and a rotary member58in meshing engagement with the second gear57and rotatably supported in such a manner as to bridge respective tips of the supporting pieces111,111in a pair of the screw support54. The supporting pieces111,111in a pair of the screw support54and the rotary member58correspond to a ring-like member.

The screw support54and the rod receiving section55are each composed of a single part. As understood fromFIG. 5, the screw support54and the rod receiving section55are connected integrally to each other in such a manner as to overlap each other partially, and are arranged side by side in a top-bottom direction in a plan view. The rod receiving section55has the U-shape groove63with the opened upper surface. The groove63is formed in a direction in which the rod member5extends. One of walls defined across the groove63of the rod receiving section55is formed into an arc-like wall65having an arc-like outer peripheral surface. The other of the walls defined across the groove63is formed into a block-like wall66having a shape like a block as a whole. A surface of the arc-like wall65and that of the block-like wall66facing each other are provided with corresponding female threads67,67. A set screw70(seeFIG. 1) is screwed into the female threads67,67. The set screw70corresponds to a fixing tool.

While not shown in the drawings, the bottom of the groove63of the rod receiving section55is provided with a circular concaved section opened at the bottom, and a through hole formed concentrically with the bottom of the circular concaved section. The first gear56(seeFIG. 6) is rotatably supported in the circular concaved section. As understood fromFIG. 5, a polygonal hole72penetrating the first gear56is formed at the center of the first gear56in a radial direction. The first gear56can be rotated by fitting a dedicated surgical instrument in the polygonal hole72and operating the fitted surgical instrument. A C-ring73is arranged on the first gear56. The C-ring73projects slightly from the bottom surface of the groove63of the rod receiving section55.

The block-like wall66is composed of a block body75and a supporting wall76projecting upward from the block body75. The above-described female threads67are formed in a range from the supporting wall76to the block body75. As understood fromFIG. 4, a surface of the block body75close to the screw support54is provided with a supporting cavity78for supporting one of the arc-like portions16of the rod receiving section11of the screw member3(seeFIG. 2). The supporting cavity78has a bottom surface where an engagement convex80is formed that is to be engaged with the engagement groove23(seeFIG. 2) provided at the outer peripheral surface of the arc-like portion16of the rod receiving section11of the screw member3. Poles79,79in a pair are formed across the supporting cavity78in such a manner as to extend in a direction in which the groove63extends, and the poles79are provided with female screw holes (not shown in the drawings) with opened upper surfaces. A fixing screw member100described later is threadedly engaged with each of the female screw holes. The supporting wall76having a substantially trapezoidal shape in a plan view is provided between the female screw holes of the block body75in such a manner as to project upward from the block body75.

A tiny gap82(seeFIG. 4) is provided between the block body75and the supporting wall76and close to the screw support54. A plate-like stopper member83is arranged in the gap82. The stopper member83is fixed in the gap82using two screw members85,85. The stopper member83is formed into a shape elongated in the direction in which the groove63extends in a plan view. The stopper member83has opposite ends as viewed in its lengthwise direction where concaved stoppers84,84are provided each arranged in such a manner as to block a tiny area around the female screw hole of the block body75. By doing so, even if the fixing screw member100described later is rotated excessively in a direction of being pulled out, male threads105of the fixing screw member100interfere with the concaved stopper84of the stopper member83, thereby preventing the fixing screw member100from coming off the corresponding female screw hole of the block body75.

As shown inFIGS. 4 and 5, the poles79,79of the block body75are provided with corresponding supporting spaces88,88rectangular in sections extending upward diagonally from outside toward the supporting cavity78in such a manner as to intersect the corresponding female screw holes and to penetrate the corresponding poles79,79. The supporting space88is formed in such a manner as to open the pole79on a side close to the screw support54. By referring further toFIG. 6, a stopper pawl section92is supported in each of the supporting spaces88in such a manner as to be movable back and forth. The stopper pawl section92has a plate-like shape and is formed into a substantially rectangular shape in a plan view. The stopper pawl section92is provided with a long hole93extending in a lengthwise direction in such a manner as to penetrate the stopper pawl section92. The fixing screw member100described latter is passed through the long hole93. The stopper pawl section92has a tip where a pawl94is formed at an end thereof as viewed in a width direction in such a manner as to project in a lengthwise direction. The stopper pawl section92is configured to allow the pawl94at the tip of the stopper pawl section92to go into and out of the supporting cavity78of the block body75, as will be described later.

As shown inFIG. 6, the fixing screw member100is composed of a hexagonal hole head101, and a shaft102with male threads105. The shaft102is composed of a small-diameter shaft section104, the male threads105, a large-diameter shaft section106, a tapered shaft section107, and a minimum-diameter shaft section108arranged in this order as viewed from the head101toward a tip. The small-diameter shaft section104has an outer diameter less than the outer diameter of the male threads105. The large-diameter shaft section106has an outer diameter less than the outer diameter of the male threads105and greater than the outer diameter of the small-diameter shaft section104. The tapered shaft section107is formed in such a manner that the outer diameter thereof is reduced gradually from the large-diameter shaft section106toward the minimum-diameter shaft section108.

As shown inFIGS. 4 to 6, the male threads105of the fixing screw member100are screwed into the female screw hole of the pole79of the block body75and the tapered shaft section107of the fixing screw member100is passed through the interior of the long hole93of the stopper pawl section92arranged in the supporting space88of each pole79. As the fixing screw member100is screwed in and is moved in the axis direction, the fixing screw member100is moved while the tapered shaft section107of the fixing screw member100is in contact with the inner wall surface of the long hole93of the stopper pawl section92. This allows the stopper pawl section92to go into and out of the supporting cavity78of the block body75.

As understood fromFIG. 5, the screw support54includes: a gear housing110connected to the rod receiving section55in such a manner as to overlap the rod receiving section55in the top-bottom direction, and the supporting pieces111,111in a pair provided integrally with the gear housing110and extending like branches from the gear housing110, and each provided integrally with and extending from a lower end portion of each of the poles79,79of the block body75of the rod receiving section55. The gear housing110has an opened lower section and the second gear57(seeFIG. 6) is housed in the gear housing110. Each of the supporting pieces111,111in a pair is provided with a housing cavity (not shown in the drawings) having an opened lower section. The rotary member58is arranged in the housing cavities in the supporting pieces111,111in a pair in such a manner as to cross the gear housing110. A substantially C-shaped cover member115is arranged at the screw support54in such a manner as to cover the second gear57in the gear housing110and to cover the rotary member58in the supporting pieces111,111in a pair from below.

By referring toFIG. 6, the cover member115is provided with a projection116projecting outward in a radial direction toward the opposite side of the opened part thereof in the radial direction. The second gear57is supported rotatably on a support pin117standing from the projection116. The second gear57is arranged to cover an area from the gear housing110of the screw support54to a position adjacent to the first gear56in the bottom of the rod receiving section55, and is in meshing engagement with the first gear56. The second gear57is also in meshing engagement with a gear118of the rotary member58. A distance between the supporting pieces111,111in a pair is set to a distance that allows the planar portions15,15in a pair at the rod receiving section11of the screw member3to come into abutting contact with the supporting pieces111,111in a pair and to be fitted therebetween.

The rotary member58is formed into a C-shape. The rotary member58extends in the housing cavities in the supporting pieces111,111in a pair in such a manner as to cross the gear housing110, and is rotatably supported in such a manner as to bridge the tips of the supporting pieces111,111in a pair. The rotary member58has an outer peripheral surface where the gear118is formed. The gear118is in meshing engagement with the second gear57. The inner diameter of the rotary member58is substantially equal to an outer diameter defined by the arc-like portions16,16in a pair of the rod receiving section11of the screw member3(seeFIG. 2). Rotating the first gear56using a dedicated surgical instrument allows the second gear57and the rotary member58to rotate. The resultant rotation of the rotary member58makes it possible to open and close the supporting pieces111,111in a pair of the screw support54relative to each other.

By referring toFIGS. 1 and 4 to 6, for attachment of the clamp member50A to the rod receiving section11of the screw member3, a dedicated surgical instrument (not shown in the drawings) is fitted in the polygonal hole72of the first gear56arranged in the bottom of the groove63of the rod receiving section55and is then rotated to one direction, thereby rotating the first gear56, the second gear57, and the rotary member58to open the supporting pieces111,111in a pair of the screw support54relative to each other. Next, while one of the arc-like portions16of the rod receiving section11of the screw member3is located in the supporting cavity78provided at the block body75of the block-like wall66at the rod receiving section55of the clamp member50A, the supporting pieces111,111in a pair of the screw support54of the clamp member50A are brought into abutting contact with the planar portions15,15in a pair of the rod receiving section11of the screw member3at positions below the groove10. Locating the one arc-like portion16of the rod receiving section11of the screw member3in the supporting cavity78at the rod receiving section55of the clamp member50A engages the engagement groove23(seeFIG. 2) provided at the outer peripheral surface of the one arc-like portion16of the rod receiving section11of the screw member3with the engagement convex80provided at the supporting cavity78of the rod receiving section55of the clamp member50A (seeFIG. 4). By doing so, the movement of the clamp member50A in the top-bottom direction relative to the screw member3is regulated.

Next, the dedicated surgical instrument (not shown in the drawings) is fitted again in the polygonal hole72of the first gear56arranged in the bottom of the groove63of the rod receiving section55and is then rotated to the opposite direction, thereby rotating the first gear56, the second gear57, and the rotary member58to close the supporting pieces111,111in a pair of the screw support54relative to each other using the rotary member58. As a result, the inner peripheral surface of the rotary member58is brought into abutting contact with the outer peripheral surface of the other arc-like portion16at the rod receiving section11of the screw member3. By doing so, while the rod receiving section11of the screw member3is held using the rotary member58, the groove10of the screw member3(rod receiving section11) is exposed to the outside.

Next, a dedicated surgical instrument (not shown in the drawings) is fitted in the hexagonal hole head101of each fixing screw member100and the surgical instrument is rotated to one direction. By doing so, each fixing screw member100is screwed in to cause each fixing screw member100to move forward in the axis direction. At this time, each fixing screw member100moves forward while the tapered shaft section107of each fixing screw member100contacts the inner wall surface of the long hole93of each stopper pawl section92, thereby causing each stopper pawl section92to move forward toward the interior of the supporting cavity78of the block body75. As a result, the pawl94of each stopper pawl section92presses the concaved section22at each planar portion15of the rod receiving section11of the screw member3. By doing so, the rod receiving section11of the screw member3is sandwiched and fixed firmly from the sides of the planar portions15,15in a pair with the stopper pawl sections92,92in a pair. In this way, by attaching the clamp member50A to the rod receiving section11of the screw member3, the clamp member50A is located close to the rod receiving section11of the screw member3.

For detaching the clamp member50A from the rod receiving section11of the screw member3, like in the case of attaching the clamp member50A, a dedicated surgical instrument (not shown in the drawings) is fitted in the hexagonal hole head101of each fixing screw member100and the surgical instrument is rotated to the opposite direction, thereby causing each fixing screw member100to move backward in the axis direction. This causes the tapered shaft section107of each fixing screw member100to move backward to cause each stopper pawl section92to move slidably under its own weight inside the supporting space88. As a result, the pawl94of each stopper pawl section92is separated from the concaved section22at each planar portion15of the rod receiving section11of the screw member3, thereby releasing the rod receiving section11of the screw member3from the sandwiching action exerted by each stopper pawl section92.

Furthermore, a dedicated surgical instrument (not shown in the drawings) is fitted in the polygonal hole72of the first gear56arranged in the bottom of the groove63of the rod receiving section55and is rotated to one direction, thereby rotating the first gear56, the second gear57, and the rotary member58to open the supporting pieces111,111in a pair of the screw support54relative to each other. In this state, the clamp member50A becomes detachable from the rod receiving section11of the screw member3.

The following describes a method of assisting in correction and fusion using the corrective appliance1A according to the first embodiment when spinal deformity is subjected to the correction and fusion by the spinal deformity correction and fusion system2on the basis ofFIGS. 7 and 8and by also referring toFIGS. 1 and 4, if appropriate. While the spinal deformity correction and fusion system2inFIGS. 7 and 8simply performs correction and fusion of the spinal deformity by using only a plurality of the screw members3and the rod members5in a pair, this is intended to facilitate understanding of the method of assisting in the correction and fusion using the corrective appliance1A according to the first embodiment. In some actual cases, a member such as the hook member4or a connector member (not shown in the drawings) is used as well as the screw member3, or another rod member is used in addition to the rod members5,5in a pair, if necessary.

As shown inFIG. 7(a), in response to spinal deformity such as scoliosis, the screw member3is first screwed into a vertebral body through a pedicle of each of vertebrae (ten vertebrae in the drawing, for example) in a range of correction and fusion of a spine from the back of the spine. Next, in response to a case such as a single curve like the one shown inFIG. 7(a), for example, the clamp member50A is attached to the rod receiving section11of the screw member3screwed into each of vertebrae that may be five vertebrae within a range from the apex to the vicinity of the apex of the curve, for example. In this method, the clamp member50A is attached in such a manner that the rod receiving section55of this clamp member50A is arranged external to the rod receiving section11of the screw member3as viewed in a crosswise direction of a patient. The explanation of the method of attaching the clamp member50A to the rod receiving section11of the screw member3is omitted here as it has already been given above.

Next, one auxiliary rod member51is prepared and the auxiliary rod member51is curved using a dedicated surgical instrument (not shown in the drawings) along a curve of the scoliosis of the spine. Then, as shown inFIG. 7(b), the auxiliary rod member51is engaged with the groove63of the rod receiving section55of each clamp member50A. Next, the set screw70is screwed into the female threads67,67of the rod receiving section55of each clamp member50A using a dedicated surgical instrument (not shown in the drawings) to temporarily tighten the auxiliary rod member51. At this time, when the auxiliary rod member51is pressed with the set screw70against the bottom surface of the groove63of the rod receiving section55of each clamp member50A, the C-ring73on the first gear56presses the first gear56against the bottom of the circular concaved section of the rod receiving section55. By doing so, the rotation of the first gear56is regulated, so that the rod receiving section11(head) of the screw member3is continuously held using the rotary member58.

Next, in the state ofFIG. 7(b), operation is performed using a dedicated surgical instrument (not shown in the drawings) to grasp and rotate the auxiliary rod member51or to move the clamp members50A in a direction of getting closer to or farther from each other, thereby correcting the spinal deformity including twisting. Next, as shown inFIG. 7(c), the set screw70of the corrective appliance1A according to the first embodiment is fully tightened to fix the auxiliary rod member51firmly to the groove62of the rod receiving section55of each clamp member50A. In this way, it becomes possible to correct the spinal deformity and to retain the corrected state using the corrective appliance1A according to the first embodiment. Next, as shown inFIG. 8(d), the rod member5is engaged with the grooves10of the rod receiving sections11of all the screw members3(ten screw members3) on the left side without the attached clamp member50A. Then, using a dedicated surgical instrument (not shown in the drawings), the set screw20is screwed into the female threads17,17of the rod receiving section11of each screw member3(seeFIG. 2) and fully tightened, thereby fixing the rod member5firmly to the groove10of the rod receiving section11of each screw member3. At this time, the rod member5may be curved slightly in such a manner as to conform to (physiological) normal backward curvature and forward curvature of the patient, if necessary, and the rod member5in this state may be engaged with the grooves10of the rod receiving sections11of all the screw members3(ten screw members3).

Next, as shown inFIG. 8(e), the rod member5is engaged with the grooves10of the rod receiving sections11of all the screw members3(ten screw members3) on the right side on which the clamp members50A are attached. Furthermore, the set screw20is screwed into the female threads17,17of the rod receiving section11of each screw member3(seeFIG. 2) and fully tightened, thereby fixing the rod member5firmly to the groove10of the rod receiving section11of each screw member3.

Next, as shown inFIG. 8(f), the set screw70is detached from the rod receiving section55of each clamp member50A and the auxiliary rod member51is detached from each clamp member50A. Then, each clamp member50A is detached from the rod receiving section11of each screw member3. By doing so, the correction and fusion of the spinal deformity by the spinal deformity correction and fusion system2(a plurality of the screw members3and the rod members5in a pair) is completed. The explanation of the method of detaching the clamp member50A from the rod receiving section11of the screw member3is omitted here as it has already been given above.

In the method shown inFIGS. 7 and 8, the clamp member50A is attached in such a manner that the rod receiving section55of this clamp member50A is arranged external to the rod receiving section11of the screw member3as viewed in the crosswise direction of the patient. Alternatively, the clamp member50A may be attached to the rod receiving section11of the screw member3in such a manner that the rod receiving section55of this clamp member50A is arranged internal to the rod receiving section11of the screw member3as viewed in the crosswise direction of the patient. In the method shown inFIGS. 7 and 8, the clamp member50A is attached to the rod receiving section11of each screw member3on the right side as viewed in the crosswise direction of the patient. Alternatively, the clamp member50A may be attached to the rod receiving section11of each screw member3on the left side as viewed in the crosswise direction. Still alternatively, the clamp member50A may be attached to the rod receiving section11of each screw member3on the both sides as viewed in the crosswise direction.

As described above, in addition to the method shown inFIGS. 7 and 8, correction and fusion of spinal deformity by the spinal deformity correction and fusion system2may be assisted in response to an intention by an operator by attaching the clamp member50A to the rod receiving section11of the selected screw member3and performing operation for correction using the attached clamp member50A and the auxiliary rod member51. In summary, the corrective appliance1A according to the first embodiment is applicable not only to the method shown inFIGS. 7 and 8but to a method different from the method shown inFIGS. 7 and 8responsive to an intention by an operator.

As described above, the corrective appliance1A according to the first embodiment of the present invention includes: the clamp member50A to be attached detachably, for example, to the rod receiving section11of the screw member3of the spinal deformity correction and fusion system2and to be arranged close to the rod receiving section11of the screw member3; and the auxiliary rod member51to be attached detachably to the rod receiving section55of the clamp member50A and to be used for correcting spinal deformity.

In this configuration, the clamp member50A is attached to each of a plurality of the screw members3, and the auxiliary rod member51is attached further to the groove63of the rod receiving section55of each clamp member50A. Next, the auxiliary rod member51is operated, making it possible to correct the spinal deformity properly through each clamp member50A and each screw member3and to retain the corrected state. Then, the rod member5is coupled to the groove10of the rod receiving section11of each screw member3to fix a spine in the corrected state. Next, the auxiliary rod member51and each clamp member50A are detached from each screw member3and then taken out of a body.

During the correction and fusion of the spinal deformity in this way by the spinal deformity correction and fusion system2, unlike in the conventional case, it is not necessary to engage the rod member5of the spinal deformity correction and fusion system2with each screw member3or each hook member4fixed to each vertebra under scoliosis deformity including twisting, or to perform operation of giving a curve to the rod member5of the spinal deformity correction and fusion system2along the scoliosis deformity or operation of firmly sandwiching the rod member5and rotating the rod member5using a dedicated surgical instrument such as a pair of pliers. As a result, it becomes possible to limit damage on the rod member5as a self-contained member. Furthermore, using the corrective appliance1A according to the first embodiment allows the rod member5of the spinal deformity correction and fusion system2to be easily engaged with (coupled to) the groove10(24) of the rod receiving section11(25) of each screw member3(hook member4). As a result, correction of the spinal deformity by the spinal deformity correction and fusion system2becomes easier to facilitate implementation of a surgery itself, thereby contributing to reduction in a duration of the surgery.

The clamp member50A used in the corrective appliance1A according to the first embodiment of the present invention includes, as a ring-like member to support the rod receiving section11of the screw member3in such a manner as to surround an outer periphery of the rod receiving section11, the supporting pieces111,111in a pair of the screw support54, and the rotary member58rotatably supported in such a manner as to open and close respective tips of the supporting pieces111,111in a pair relative to each other. This allows the groove10provided at the rod receiving section11of the screw member3and used for engagement with the rod member5to be exposed to the outside. As a result, while spinal deformity is corrected and the corrected state is retained using the clamp member50A and the auxiliary rod member51, the rod member5can be engaged easily with the groove10of each screw member3.

The clamp member50A used in the corrective appliance1A according to the first embodiment of the present invention further includes the set screw70to be used for fixing the auxiliary rod member51to the groove63of the rod receiving section55of the clamp member50A. By operating the auxiliary rod member51while the auxiliary rod member51is temporarily tightened to the groove63of each clamp member50A using the set screw70, it becomes possible to correct spinal deformity easily through each clamp member50A. After the correction, the auxiliary rod member51is fixed firmly to the groove63of the rod receiving section55of each clamp member50A using the set screw70. By doing so, the spinal deformity can be retained in the corrected state using the clamp member50A and the auxiliary rod member51.

The clamp member50A used in the corrective appliance1A according to the first embodiment of the present invention further includes the stopper pawl sections92,92in a pair for sandwiching the rod receiving section11of the screw member3, in addition to the supporting pieces111,111in a pair of the screw support54and the rotary member58rotatably supported in such a manner as to open and close respective tips of the supporting pieces111,111in a pair relative to each other. The stopper pawl sections92,92in a pair can be used for fixing the clamp member50A to the screw member3more firmly. As a result, force of the correction applied from the clamp member50A can be transmitted properly to a vertebra through the screw member3, making it possible to correct spinal deformity properly.

Furthermore, the planar portion15of the screw member3is provided with the concaved section22for supporting the tip of the pawl94of the stopper pawl section92of the corrective appliance1A according to the first embodiment of the present invention. When the clamp member50A is attached to the screw member3, the stopper pawl section92of the clamp member50A is engaged with the concaved section22of the screw member3. This makes it possible to minimize backlash of the clamp member50A relative to the screw member3occurring during attachment of the clamp member50A to the screw member3.

The corrective appliance1A according to the first embodiment uses the auxiliary rod member51as a corrective member to be engaged with the groove63of the rod receiving section55of the clamp member50A. This corrective member may be a shaft member, for example, to be attached detachably to the clamp member50A and to extend from the clamp member50A toward the outside of a body. If such a shaft member is used, spinal deformity can be corrected properly by causing an operator to grasp and operate each shaft member projecting to the outside of the body or to operate the shaft member using a surgical instrument. A member such as that for retention of correction for retaining a corrected state may be mounted on a tip of each shaft member.

While the corrective appliance1A according to the first embodiment functions as a surgical instrument to be taken out of a body after spinal deformity is subjected to correction and fusion by the spinal deformity correction and fusion system2, it can indwell as it is in the body. In this case, like the screw member3, the hook member4, the rod member5, etc., of the spinal deformity correction and fusion system2, the corrective appliance1A according to the first embodiment is required to be made of a material of excellent biocompatibility such as titanium alloy. This allows improvement of the rigidity of the spinal deformity correction and fusion system2as a whole, making it possible to reduce the occurrence of breakage of the rod member5, for example.

A corrective appliance1B according to a second embodiment of the present invention will be described in detail on the basis ofFIGS. 9 to 14. In describing the corrective appliance1B according to the second embodiment, only a difference from the corrective appliance1A according to the first embodiment will be described. In the corrective appliance1B of the second embodiment, the configuration of a clamp member50B used in the corrective appliance1B differs from that of the clamp member50A used in the corrective appliance1A according to the first embodiment. Thus, in the following, the configuration of the clamp member50B will be described in detail.

As shown inFIGS. 9, 10, and 14, the clamp member50B includes: supporting pieces160,170in a pair movable closer to and farther from each other to support the rod receiving section11of the screw member3; a rod receiving section162connected integrally to the one supporting piece160of the supporting pieces160,170in a pair and having a U-shape groove167with an opened upper surface; and a wedge slide member152to move in the top-bottom direction to make the other supporting piece170of the supporting pieces160,170in a pair movable closer to and farther from the one supporting piece160. In other words, the clamp member50B is formed by coupling and integrating a main body unit150shown inFIGS. 11 and 12, a secondary body unit151shown inFIG. 13, the wedge slide member152shown inFIG. 14, an operative screw member153shown inFIG. 14, and a regulating plate member154shown inFIG. 14each configured using a single part.

As shown inFIGS. 11 and 12, the main body unit150is formed by connecting the one supporting piece160, a main body unit section161, and the rod receiving section162integrally to each other. The one supporting piece160extends from the lower end of the main body unit section161in a direction substantially orthogonal to a direction in which the groove167of the rod receiving section162extends. The one supporting piece160extends from the lower end of the main body unit section161, which corresponds to one end side as viewed in the direction in which the groove167of the rod receiving section162extends. The main body unit section161has a front side (a side closer to the one supporting piece160) where an arc-like screw abutting surface163is provided in such a manner as to be continuous with the one supporting piece170. One of the arc-like portions16provided at the rod receiving section11of the screw member3shown inFIG. 9is to abut on the screw abutting surface163. The main body unit section161has a back side (a side on the opposite side of the one sporting piece160) to which the rod receiving section162is integrally connected.

A housing hollow section165is formed in the main body unit section161. The housing hollow section165has an opened upper surface having an arbitrary shape, is opened at the other end side as viewed in the direction in which the groove167of the rod receiving section162extends, and has an opened front side (a side closer to the one supporting piece160) having a substantially rectangular shape as viewed in the direction in which the groove167of the rod receiving section162extends. A secondary body unit section171of the secondary body unit151and the wedge slide member152described later in detail are housed in the housing hollow section165while a wedge projection182provided at the wedge slide member152is engaged with an inclined space178provided at the secondary body unit section171. A housing cavity164is formed at the upper surface of the main body unit section161and at one end of the main body unit section161closer to the one supporting piece160.

The rod receiving section162has the U-shape groove167with the opened upper surface. The groove167is formed in the direction in which the rod member5extends (seeFIG. 9). Walls166,166facing each other across the groove167of the rod receiving section162have inner wall surfaces at which corresponding female threads168,168are formed. A set screw169shown inFIG. 9is screwed into the female threads168,168. The set screw169corresponds to a fixing tool for fixing the auxiliary rod member51to the groove167of the clamp member50B.

The rod receiving section162, specifically, the wall166,166thereof project more upward than the upper surface of the main body unit section161as shown inFIG. 11, and more upward than the regulating plate member154fixed in such a manner as to cover the upper surface of the main body unit section161as shown inFIG. 10. This allows a rod-like surgical instrument (not shown in the drawings), used for assisting in the operation of inserting the auxiliary rod member51(seeFIG. 9) into the groove167of the rod receiving section162, to be mounted at its tip on the projecting portions of the walls166,166. As shown inFIG. 11, the bottom surface of the groove167of the rod receiving section162is located above the one supporting piece160. As shown inFIG. 13, the secondary body unit151is formed by connecting the other supporting piece170and the secondary body unit section171to each other integrally. The other supporting piece170extends from the lower end of the secondary body unit section171in a direction substantially orthogonal to the direction in which the groove167of the rod receiving section162extends. The other supporting piece170extends from the lower end of the secondary body unit section171, which corresponds to the other end side as viewed in the direction in which the groove167of the rod receiving section162extends.

The secondary body unit section171includes: a plate-like body174having a plate-like shape of a predetermined width and extending in a standing position in the direction in which the groove167of the rod receiving section162extends; and a large inclination piece175A and a small inclination piece175B in a pair connected integrally to the back surface (a surface on the opposite side of the other supporting piece170) of the plate-like body174. An arc-like screw abutting surface172is provided spaced from and below the plate-like body174of the secondary body unit section171in such a manner as to be continuous with the other supporting piece170. One of the arc-like portions16at the rod receiving section11of the screw member3shown inFIG. 9is to abut on the screw abutting surface172. The inclined space178of a predetermined width inclined downward toward the other supporting piece170(toward the other end) is formed between the large inclination piece175A and the small inclination piece175B in a pair. The thickness of the small inclination piece175B on one end side is smaller than that of the large inclination piece175A on the other end side. The wedge projection182provided at the wedge slide member152(seeFIG. 14) is engaged with the inclined space178.

As shown inFIG. 14, the wedge slide member152includes a plate-like section180and a cylindrical section181connected integrally to one end portion of the plate-like section180. The wedge slide member152is housed in its entirety in the housing hollow section165at the main body unit section161of the main body unit150. The plate-like section180is provided in a standing position, and has a front side where the wedge projection182projects at the other end on the opposite side of the cylindrical section181. The wedge projection182is formed into a shape like a parallelogram in a front view having a predetermined width and inclined downward toward an attachment bolt193(toward the other end). The wedge projection182is engaged with the inclined space178at the secondary body unit151and has a width substantially equal to that of the inclined space178. The cylindrical section181has an inner peripheral surface provided with female threads (not shown in the drawings). Male threads190of the operative screw member153are threadedly engaged with these female threads.

The operative screw member153is composed of a head189having an upper surface with a hexagonal hole188, and the male threads190provided continuously in an axis direction from the head189. The male threads190are threadedly engaged with the female threads provided at the inner peripheral surface of the cylindrical section181of the wedge slide member152. The head189of the operative screw member153is housed in the housing cavity164provided at the upper surface of the main body unit section161of the main body unit150. The regulating plate member154for regulating the movement of the operative screw member153in the top-bottom direction is arranged on the head189of the operative screw member153. Specifically, as shown inFIG. 10, the head189of the operative screw member153is sandwiched between the housing cavity164of the main body unit150(main body unit section161) and the regulating plate member154to support the operative screw member153rotatably while being unmovable in the top-bottom direction.

The regulating plate member154is provided with an opening192formed at a position corresponding to the head189of the operative screw member153so as to expose the hexagonal hole188at the head189of the operative screw member153to the outside. As shown inFIG. 10, the regulating plate member154is fixed to the main body unit150with the attachment bolt193in such a manner as to cover the upper surface of the main body unit section161of the main body unit150and the head189of the operative screw member153. As described above, as the opening192is formed at the regulating plate member154, the hexagonal hole188at the head189of the operative screw member153is exposed to the outside.

While the wedge projection182at the wedge slide member152is engaged with the inclined space178at the secondary body unit151, the secondary body unit section171of the secondary body unit151and the wedge slide member152are arranged in the housing hollow section165of the main body unit150. In this state, the wedge slide member152is housed movably in the top-bottom direction and the secondary body unit151is housed movably in the direction in which the groove167of the rod receiving section162extends. As a result, as shown inFIG. 10, the one supporting piece160of the main body unit150and the other supporting piece170of the secondary body unit151are arranged in such a manner as to face each other.

The male threads190of the operative screw member153are arranged in the housing hollow section165of the main body unit150while being threadedly engaged with the female threads at the cylindrical section181of the wedge slide member152. The head189of the operative screw member153is housed in the housing cavity164of the main body unit150(main body unit section161), and the upper surface of the head189and the upper surface of the main body unit150(main body unit section161) except the housing cavity164are arranged on substantially the same plane. Furthermore, the regulating plate member154is arranged in such a manner as to cover the upper surface of the main body unit section161of the main body unit150and the head189of the operative screw member153, and is fixed with the attachment bolt193to the main body unit150. In this way, the clamp member50B used in the corrective appliance1B according to the second embodiment is completed.

For attachment of the clamp member50B of the corrective appliance1B according to the second embodiment to the rod receiving section11of the screw member3, a dedicated surgical instrument not shown in the drawings is fitted in the hexagonal hole188of the head189of the operative screw member153and the dedicated surgical instrument is operated to one direction, thereby rotating the operative screw member153to the one direction. As a result, as the operative screw member153is supported in such a manner as to be unmovable in the top-bottom direction, the wedge slide member152is moved upward. This produces wedge effect between the wedge projection182at the wedge slide member152and the large inclination piece175A and the small inclination piece175B in a pair at the secondary body unit section171of the secondary body unit151to move the other supporting piece170of the secondary body unit151in a direction of getting father from the one supporting piece160of the main body unit150.

Next, the clamp member50A is arranged in such a manner as to locate the supporting pieces160,170in a pair thereof at positions on the planar portions15,15in a pair of the rod receiving section11of the screw member3below the groove10. At this time, one of the arc-like portions16of the rod receiving section11of the screw member3comes into abutting contact with the screw abutting surface163belonging to the main body unit150of the clamp member50A and with the screw abutting surface172belonging to the secondary body unit151.

Next, the dedicated surgical instrument not shown in the drawings is fitted again in the hexagonal hole188of the head189of the operative screw member153and the fitted dedicated surgical instrument is rotated to the opposite direction, thereby rotating the operative screw member153to the opposite direction. As a result, the wedge slide member152moves downward to produce wedge effect between the wedge projection182at the wedge slide member152and the large inclination piece175A and the small inclination piece175B in a pair at the secondary body unit section171of the secondary body unit151, thereby moving the other supporting piece170of the secondary body unit151in a direction of getting closer to the one supporting piece160of the main body unit150.

As a result, it becomes possible to firmly clamp the screw member3at positions on the planar portions15,15in a pair of the rod receiving section11below the groove10in such a manner as to clamp the screw member3from opposite lateral sides using the supporting pieces160,170in a pair of the clamp member50B. At this time, as the screw member3is sandwiched at the positions on the planar portions15,15in a pair of the rod receiving section11of the screw member3below the groove10using the supporting pieces160,170in a pair of the clamp member50B, the groove10of the screw member3(rod receiving section11) can be exposed to the outside.

The clamp member50B used in the corrective appliance1B according to the second embodiment of the present invention includes the supporting pieces160,170in a pair movable closer to and farther from each other. This makes it possible to firmly clamp the screw member3at positions on the planar portions15,15in a pair of the rod receiving section11below the groove10in such a manner as to clamp the screw member3from opposite lateral sides using the supporting pieces160,170in a pair. Thus, the groove10at the rod receiving section11of the screw member3can be exposed to the outside. As a result, while spinal deformity is corrected and the corrected state is retained using the clamp member50B and the auxiliary rod member51, the rod member5can be engaged easily with the groove10of each screw member3.

REFERENCE SINGS LIST

2Spinal deformity correction and fusion system

50A,50B Clamp member