Spinal implant and device for spinal fixing

1. A spinal fixation device comprising:

a screw part having a screw body part configured to be implanted in a spine;

a head part that is attached to a portion on an opposite side of the screw part to the screw body part and has a slit into which a fixing rod for fixing a plurality of vertebrae is to be inserted, wherein the head part includes:

a base part that is provided as a portion on the screw part side of the head part and in which the fixing rod inserted into the slit is held; and

a pair of tab parts that are formed so as to face each other across the slit extend in a first direction, wherein the first direction extends from the base part to an opposite side to the screw part,

a pair of extenders that each engage a respective tab part from the pair of tab parts, wherein each of the pair of extenders includes a blade that extends in the first direction, and

weak parts formed between the base part and each of the pair of tab parts, wherein the weak parts are configured to be broken by an external force from the pair of extenders; and

an extender guard that is substantially cylindrical and elongated in the first direction, wherein the extender guard includes two grooved parts formed on an inner circumference surface of the extender guard that extend in the first direction, wherein the two grooved parts are configured to receive each blade from the pair of extenders.

2. The spinal fixation device according to claim 1 ,

wherein each of the pair of tab parts include:

a slide guide part that is formed on the tab parts to enable a slide part formed on the extender to slide, and

a receiving part that is formed on the tab parts and into which a protrusion of a spring of the extender is to fit.

3. The spinal fixation device according to claim 2 ,

wherein the slide guide part is formed, so as to extend in the first direction, in a portion on both sides of the tab parts in a width direction, which is a second direction that is orthogonal to the first direction, so as to enable the slide part of which two are formed on each of the pair extenders to slide.

4. The spinal fixation device according to claim 3 ,

wherein each tab from the pair of tabs further includes a slide guide part and a receiving part that are formed on the tab parts, and

wherein each of the pair of extenders further includes an extender-side engagement part includes a slide part that is able to slide with respect to the slide guide part, and a protrusion that is formed on a spring attached to each of the pair of extenders and is configured to fit into the receiving part formed on the tab parts.

5. The spinal fixation device according to claim 2 ,

wherein the slide part is formed so as to extend in the direction in which the fixing rod is guided in the extender, and

the spring is formed so as to extend in the direction in which the slide part extends, and is provided as a blade spring that has the protrusion formed at one end and is fixed at the other end to each of the pair of extenders.

6. The spinal fixation device according to claim 1 ,

wherein the each blade of the pair of extenders includes guide members are more elastically deformable than the weak parts.

7. The spinal fixation device according to claim 6 ,

wherein each of the pair of extenders further includes: a base end part on an opposite side and separated along in the first direction from an extender-side engagement part; and an intermediate part between the extender-side engagement part and the base end part, and

the spinal fixation device further comprises a cap that is configured to externally cover the base end of each of the pair of extenders so as to restrict each blade of the pair of extenders from moving closer to or away from each other.

8. The spinal fixation device according to claim 1 , wherein each of blade of the pair of extenders includes an elongated through-hole that extends in first direction;

wherein the pair of extenders are configured to position each blade so that each elongated through-hole faces each other.

9. The spinal fixation device according to claim 8 , wherein the a pair of extenders each further includes a marking formed in a vicinity of a center of each elongated through-hole, wherein the marking enables a relative positioning of the extender guard with respect to the pair of extenders.

10. The spinal fixation device according to claim 1 , further comprising:

a tab remover that is configured by a member that is less elastically deformable than each blade of each of the pair of extenders and the weak parts, and is configured to separate the pair of tab parts from the base part by the external force being applied to the tab remover mounted on the extender to break the weak parts.

11. The spinal fixation device according to claim 1 , wherein the extender guard further includes a plurality of recesses.