WO2012020707A1 - Three-dimensional guide for wire for preparing pedicle screw insertion hole - Google Patents

Abstract

[PROBLEM] To provide a three-dimensional guide for a wire used to prepare an insertion hole for the insertion of a pedicle screw when inserting a pedicle screw at an appropriate anatomic location, and a manufacturing method thereof. [SOLUTION] The three-dimensional guide for a wire for preparing a pedicle screw insertion hole is prepared on the basis of a CT image of the spine, and is characterized in that the three-dimensional guide has a contact surface section, which abuts and is in surface contact with the surface of the bone at the insertion site, and a guide block section provided so as to stand upright from the contact surface section, wherein the guide block section has a guide hole that restricts the direction of insertion of the wire for preparing the insertion hole.

Description

Three-dimensional guide for insertion hole preparation wire for pedicle screw

The present invention relates to an insertion guide for an insertion hole producing wire for a pedicle screw suitable for inserting a pedicle screw used in spinal surgery into an anatomically appropriate site, and a method for manufacturing the same. About.

The spine bone not only allows movement in any direction, but also serves to protect many veins, arteries, nerves, and the like in the body.
In adults, the spine consists of more than 20 separate bones that are interconnected via a posterior intervertebral joint located between adjacent vertebrae and a cartilage disc (disc).
The bones of the spine are anatomically classified into four parts and are called cervical vertebrae, thoracic vertebrae, lumbar vertebrae and sacral vertebrae.
These areas also form unique curvatures and are known as cervical lordosis, thoracic kyphosis, lumbar lordosis and sacral kyphosis.

In such spine surgery, a pedicle screw may be used to obtain a therapeutic effect by fixing the spine.
However, the shape of the spine varies greatly from person to person, especially in the case of scoliosis, etc., and large deformation has occurred, and death due to limb paralysis due to spinal cord injury or vertebral artery damage during pedicle screw insertion Have been reported to cause serious complications.
Therefore, in Non-Patent Document 1, the CT image was developed at the same magnification, the position and angle for inserting the pedicle screw were directly drawn on the CT film, and the line was cut to include the contour of the vertebral dorsal side. A CT cutout method using a CT film has been proposed.
However, this technique was uneasy about the stability of the insertion direction even if the insertion position was obtained accurately.

Hiroshi Miyamoto, Japanese Society for Spine and Spinal Cord Disease 19 (1) 2008, P31

The present invention relates to a three-dimensional guide device for a wire used for making an insertion hole for inserting a pedicle screw when inserting the pedicle screw into an anatomically appropriate position, and its manufacture. The purpose is to provide a method.

A three-dimensional guide device according to the present invention is a three-dimensional guide device for a pedicle screw insertion hole manufacturing wire manufactured based on a CT image obtained by imaging a spine. It has a contact surface portion that abuts and contacts the bone form surface in a planar manner, and a guide block portion erected from the contact surface portion, and the guide block portion has a guide hole that regulates the insertion direction of the insertion hole forming wire. It is characterized by having.
In order to insert the pedicle screw into the pedicle, an insertion hole of the pedicle screw needs to be made in the pedicle in advance in an anatomically appropriate direction and depth.
In such a case, a K-wire is inserted into the pedicle, and then a pilot hole is created in the pedicle using a drill having a hollow center based on the K-wire inserted into the pedicle.
Next, it is necessary to extract the drill while leaving the K wire, and to form a screw thread on the inner peripheral portion of the prepared hole previously formed by using the tap having a hollow center.
The present invention is characterized by providing a three-dimensional guide that contributes to stabilization of the insertion position and insertion direction of the K wire.
In this case, the spinal vertebral arch has lateral processes, spinous processes, articular processes, etc., so that the abutting surface portion is pierced so that the position of the three-dimensional guide is easily stabilized during surgery. In addition to the morphological surface of the bone at the entry site, it is preferable to have a protrusion abutting portion that abuts against the protrusion portion of the vertebral arch, and in terms of insertion stability, the length of the guide hole is 15 mm to 30 mm. The degree is preferred.
If the length of the guide hole is less than 15 mm, the direction of insertion becomes unstable. If the length of the guide hole exceeds 30 mm, the insertion direction becomes stable, but the standing height of the guide block increases.

As a method of manufacturing such a three-dimensional guide device, there are a step of taking a spine as a CT image, a step of extracting a site for inserting a pedicle screw based on the CT image, and a step of extracting the inserted site of insertion. It is possible to form a block-shaped plan having a contact surface portion that matches the bone form surface, to produce a mold based on the plan, and to mold based on the mold.

The three-dimensional guide device for the pedicle screw insertion hole producing wire according to the present invention has a contact surface portion so as to coincide with the morphological surface of the bone, and three-dimensionally guides the insertion direction of the wire. Since it has a guide hole, it can be safely and stably inserted into an appropriate place in any part of the spine.

An example of a bone model of a cervical vertebra is shown, and an example of a three-dimensional guide device manufactured so as to abut and come into contact with the morphological surface of the bone is shown. An example in which the three-dimensional guide device according to the present invention is brought into contact with the cervical vertebra and the guide hole is positioned is shown. ) Shows an example in which the guide hole 13 is positioned by applying the projection contact portion 14 to the projection portion 2 of the bone. A state in which the cervical vertebra is viewed from the side is shown, and an example in which the insertion direction of the K wire is determined by the guide hole 13 so as not to damage the vertebral artery 3 is shown. (A) is before applying a three-dimensional guide tool to a cervical spine, (b) shows the subsequent. The positional relationship between the pedicle and the three-dimensional guide is shown using a cross-sectional view of the pedicle. (A) is before the three-dimensional guide device is applied to the pedicle, and (b) is a state in which the concave projection contact surface 14a formed on the three-dimensional guide device is in contact with the bone projection 2. Indicates. (C) shows the figure which looked at the three-dimensional guide tool from the bottom. The front view which applies a three-dimensional guide implement to a pedicle is shown. (A) is a partial cross-sectional view of the state before applying and (b) is applied. The state which inserts K wire along the guide hole formed in the three-dimensional guide tool is shown. (A) shows before insertion of K wire, and (b) shows the state of insertion. (C) shows the state which removes a three-dimensional guide tool from K wire. An example of drilling K-wires on the pedicle using a hollow drill is shown. (A) shows a state through a hollow portion of the drill K wire, state, a state (c) is the formation of the prepared hole P ₁ (b) is obtained by drilling. An example will be shown in which a K wire is tapped using a hollow tap on the inner periphery of the prepared hole. (A) shows the state where the tap is passed through the K wire, (b) shows the tapped state, and (c) shows the state where the insertion screw hole of the pedicle screw is formed. An example is shown in which a pedicle screw is inserted into an insertion screw hole formed in the pedicle using a dedicated screwdriver. (A) shows the state before insertion of the pedicle screw, (b) shows the inserted state, and (c) shows the state where the driver is removed. The example which connected the some pedicle screw with the rod is shown.

DESCRIPTION OF SYMBOLS 1 Bone 2 Process 10 Three-dimensional guide 11 Contact surface part 12 Guide block part 13 Guide hole 14 Projection contact part 20 Pedicle screw

The three-dimensional guide device according to the present invention can be applied to any part of the spine, and will be described below using the cervical spine as an example.
First, the bone shape of the surgical site is captured and captured as a CT image, and a bone model A shown as an example in FIG.
Since the bone has a complex shape in which the vertebra is connected via the intervertebral disc, the anatomically appropriate insertion direction and depth of the pedicle screw are planned from this bone model A and CT images. To do.

The spine bone (vertebral arch) 1 has processes 2 such as a transverse process, a spinous process, and an articular process, and the surface of the bone has a complicated uneven shape.
Further, as shown in FIGS. 3 and 4, the vertebral artery 3 is running.
When these are taken into consideration and the insertion site and the insertion direction are determined anatomically, the shapes (plans) of a plurality of, for example, three three-dimensional guides 10, 10A, 10B in FIG. To set up.
In preparing the shapes of the three-dimensional guides 10, 10A, and 10B, the sizes of the contact surface portions 11, 11A, and 11B that are in contact with each other in a surface contact state along the shape of the unevenness of the bone at the insertion site, And it is necessary to set the shape and size of the guide block parts 12, 12A, 12B.
Hereinafter, the description will be given by using the three-dimensional guide tool 10, and the other parts are denoted by corresponding reference numerals and the description thereof is omitted.
In that case, the abutment surface portion is provided with a protrusion abutting portion 14 that abuts also on the protrusion (spinous process) 2 of the vertebral arch so that the three-dimensional guide device 10 can be positioned simply by abutting on the vertebra.
In this way, just by placing the three-dimensional guide 10 near the insertion site, the shape of the contact surface consisting of a gentle uneven surface of the bone at the insertion site and the projection contact portion consisting of a sharp slope The position of the three-dimensional guide 10 is inevitably accurately determined by the shape and does not shift.
Although details will be described later, after inserting the K-wire to form an insertion hole for inserting the pedicle screw, it is necessary to remove the three-dimensional guide tool 10 so as to be pulled out from the rear. An undercut portion is prevented from occurring in the shape of the contact surface portion 11 and the protrusion contact portion 14.
In the present embodiment, the projection contact portion 14 is formed with a recess-shaped projection contact surface 14 a that matches the shape of the spinous process 2, but the projection contact portion 14 may be an effective projection portion for positioning the three-dimensional guide 10. It is not limited to this.

The shape of the guide block portion 12 is to guide and guide the insertion direction of the K wire 20 by forming guide holes 13 along the guide block portion 12.

When the shape (plan) of the three-dimensional guide tool 10 is determined, a mold having this plan is manufactured.
A resin or the like is injected into the mold to produce a three-dimensional guide having a predetermined shape.
The three-dimensional guide 10 manufactured in this manner can accurately determine the insertion position and direction of the K wire simply by being applied to the insertion site of the spine.

Next, a procedure for producing an insertion hole for a pedicle screw using the three-dimensional guide 10 produced in this manner will be described.
FIG. 2 is a view from the back of the cervical spine, and FIG. 3 is a view from the side.
4 shows a cross-sectional view of the pedicle, and FIG. 5 shows an enlarged view of the spinous process 2 portion.
As shown in FIG. 2 to FIG. 5A, a three-dimensional guide 10 manufactured in advance based on a CT image has a protrusion contact surface 14a formed with a recess-shaped protrusion contact surface 14a that matches the protrusion shape of the spinous process 2. It has a contact portion 14, a contact surface portion 11 that makes contact with the surface along the morphological surface of the bone from the spinous process 2 to the insertion site of the pedicle screw 50, and a guide block portion 12 in which a guide hole 13 is formed.
Here, the abutment surface portion 11 is intended to contact the surface substantially along the morphological surface of the bone, and does not necessarily need to be in contact with the entire surface of the abutment surface portion 11.

When the three-dimensional guide 10 is applied to a bone morphological surface corresponding to a planned surgical site, the concave-shaped protrusion abutting surface 14a matches the shape of the spinous process 2 of the bone, and guides from the spinous process 2 Positioning is performed when the uneven surface shape of the surface contact portion up to the hole 13 matches the uneven surface shape of the bone, and the insertion direction of the K wire 20 is the guide hole as shown in FIG. It is accurately determined by the direction of 13 through holes.
The K wire is a wire having a diameter of 1 to 2 mm, and the guide hole 13 preferably has an inner diameter slightly larger than the outer diameter of the K wire, and its length is preferably 15 mm or more.
The longer guide hole 13 improves the stability in the insertion direction, but may be 30 mm or less in consideration of insertion workability and manufacturability of the guide block portion 12.
Thus, since the K wire 20 is inserted along the guide hole 13 of the three-dimensional guide 10, the artery 3 and the like are not damaged.
When the K wire 20 is inserted into the pedicle as shown in FIG. 6B, the three-dimensional guide 10 is removed from the K wire 20 as shown in FIG. 6C.
Next, as shown in FIG. 7, a drill 30 having a hollow center portion is inserted into the pedicle while rotating through the K wire 20, thereby forming a pilot hole P _{1 as} shown in FIG. 7C. .
Then the insertion hole P ₂ of the pedicle screw thread groove by inserting while rotating the tap 40 along a prepared hole P ₁ relying the K wire 20 (tapping drill) is formed as shown in FIG. 8 can get.
Next, as shown in FIG. 9, the male screw portion 50 a of the pedicle screw 50 is screwed in using a dedicated driver 60.
The bone 1 is fixed by adjusting the angle of the head 50b of the pedicle screw 50 inserted in this way and connecting with the rod 70 as shown in FIG.
The external diameter of the male screw portion of the pedicle screw 50 is generally 3.5 to 4 mm.

Can be used at many facilities where spine surgery is performed.

Claims (4)

A three-dimensional guide for a pedicle screw insertion hole production wire produced based on a CT image of the spine,
The three-dimensional guide device has a contact surface portion that abuts and comes into contact with the bone form surface of the insertion site, and a guide block portion erected from the contact surface portion,
The three-dimensional guide tool characterized in that the guide block portion has a guide hole for regulating the insertion direction of the insertion hole producing wire. The three-dimensional guide device according to claim 1, wherein the contact surface portion includes a protrusion contact portion that contacts the protrusion portion of the vertebral arch in addition to the bone morphological surface of the insertion site. The three-dimensional guide device according to claim 1 or 2, wherein the guide hole has a length in a range of 15 mm to 30 mm. Capturing the spine as a CT image;
Extracting a site to insert a pedicle screw based on the CT image;
Creating a block-like plan having a contact surface portion that matches the bone morphological surface of the extracted insertion site;
Producing a mold based on the method;
A method for producing a three-dimensional guide device for an insertion hole producing wire for a pedicle screw, which is formed on the basis of the mold.

Images