JP7519074B2 - Needle guide device - Google Patents

Description

The present invention relates to a needle guide device for performing accurate percutaneous needle insertion into a target site in a subject's body using image data from a CT scanner (computer tomography device) or the like as an index.

When using CT or other image data as an indicator to perform a percutaneous needle puncture at a target site in a subject's chest or abdomen, the examiner confirms the target site, determines the insertion position, depth, and direction of the puncture needle (puncture route), and while checking the tip of the puncture needle under the image, punctures while holding the needle parallel to the cross section of the CT image so that the tip does not deviate from the cross section. In particular, the examiner is required to reproduce the puncture route determined on the image and perform the puncture, and therefore how accurately the puncture is performed is an important point in the procedure.

Nowadays, there are CT scanners that can continuously scan cross sections and observe images in real time, and by constantly checking the needle tip under CT fluoroscopy as the procedure progresses, it has become relatively easy to perform a highly accurate puncture. However, because X-rays are continually emitted inside the gantry of a continuous CT scanner, managing direct radiation exposure to the examiner during the procedure becomes an issue.

In order to solve this problem of radiation exposure, a puncture needle guide device has been proposed that provides a certain distance between the insertion position of the puncture needle and the insertion operation position of the puncture needle so that the needle can be inserted from outside the position inside the gantry where X-rays are irradiated (X-ray radiation area). The puncture needle guide device is an instrument that is composed of a guide tube with an insertion hole that serves as an insertion passage for the puncture needle, which is placed inside the gantry of the CT device, which is the X-ray radiation area, a support pillar that stands upright parallel to the guide tube and is placed outside the X-ray irradiation area, a beam with a certain length that connects the guide tube and the support pillar, and a leg that is placed coaxially with the support pillar and has a variable adjustment of the length of projection from the support pillar in the axial direction. (Patent Document 1) According to this device, the guide tube, which is the insertion position of the puncture needle, is positioned in the X-ray radiation area inside the gantry, the support pillar which serves as the operating grip of the guide device is positioned in a position not exposed to X-rays, the needle tube of the puncture needle is set long, and the puncture needle is inserted by bending the needle from outside the X-ray exposure area. This means that even when the needle is inserted under CT fluoroscopy, which allows accurate insertion into the target area, there is no risk of radiation exposure to the examiner, and there is no need to remove the examinee from the gantry during the puncture procedure.

JP 2000-116664 A

The conventional puncture needle guide device has a function of changing the length of the support and legs in the axial direction as one of the means for adjusting the position and angle of the device on the body surface for accurate needle insertion into the target puncture site (for example, to hold the needle parallel to the cross section of a CT image so that the needle tip does not come off the cross section). Specific means for this include a configuration using a concentric sliding tube, a configuration using a helical screw, a configuration in which legs that can slide up and down are stopped by tightening a screw, and a configuration in which legs that can slide up and down are attached to the support by a handle. However, there is no description of a specific proposal for the configuration using the concentric sliding tube, and there are concerns that with a configuration using a helical screw or tightening a screw, it takes time to adjust the length and the operation is cumbersome, and there is also a concern that with a configuration using a handle attached, the structure becomes complicated. In the conventional devices, adjusting the length of the support and legs is cumbersome.

The present invention aims to provide a puncture needle guide device that can quickly and easily adjust the settings of the device on the body surface when inserting a puncture needle into a specific area inside the body using image data such as CT scans as an indicator, without exposing the examiner to X-rays, and that is used to accurately insert the needle into the target area.

The present invention relates to a puncture guide device for percutaneously puncturing a target site of a subject using image data such as CT scans as an index, the device comprising: a guide section having a passage for guiding the puncture needle to an insertion position; a support post serving as a gripping section of the device and disposed substantially parallel to the guide section at a predetermined distance; a beam connecting the guide section and the support post; and an adjuster including a body surface contact section that is disposed coaxially with the support post and capable of varying the length of protrusion from the support post.
The inner peripheral surface of the support and the outer peripheral surface of the adjuster are formed with threaded portions that screw into each other, and either one of the threaded portions is formed only in a partitioned area that is a part of the inner peripheral surface or the outer peripheral surface and is partitioned from the surroundings, and the threaded portion of the partitioned area is formed so as to be able to be flexibly deformed outwardly or inwardly by contact and pressure from the threaded portion formed on the peripheral surface of the other side,
The means for adjusting the protruding length of the adjuster from the support includes a sliding means for moving the adjuster in a parallel direction along the axis of the support as a result of the partition portion being flexibly deformed, and a rotating means for moving the adjuster in a circumferential direction as the screw portion is screwed into the sliding means.

It is also preferable that the sliding means slides only in the extension direction in which the adjuster protrudes from the support, and sliding in the shortening direction in which the adjuster is stored in the support is restricted, and that the rotating means is configured to be able to move in both the extension and retraction directions .

As a specific configuration for enabling flexural deformation of the screw portion of the partitioned area, it is preferable that the partitioned area is partitioned from the surrounding area by gaps formed by cuts, except for the connection portion connecting to the inner or outer circumferential surface , and it is desirable to form the size of the partitioned area so that the width in the circumferential direction is 5 mm or more and 12 mm or less, and the length in the axial direction is 15 mm or more and 25 mm or less.

Furthermore, it is preferable that the partition portion is formed so as to protrude from the surrounding surface, and that the peripheral surface including the partition portion has a plurality of rows of ridges formed thereon, the ridges protruding from the surrounding surface and extending in the axial direction and having the same height as the valleys of the threaded portion formed in the partition portion, and that the outer diameter or inner diameter formed by the partition portion and the plurality of ridges matches the inner diameter or outer diameter of the threaded portion formed on the surface on the other side.

In addition, as a specific configuration , it is preferable that the sliding in the contracting direction is restricted by forming a screw portion provided in the partition portion into a sawtooth shape.

Furthermore, it is preferable that the partitioned area is formed on the inner surface of a cylindrical support.

According to the above-mentioned means, when adjusting the height of the support of the guide device by adjusting the protruding length of the adjuster from the support, by using a combination of a quick axial sliding means and a gradual circumferential rotating means as the operating means, it is possible to quickly adjust the approximate position by the sliding means, and then finely adjust to the exact position by the rotating means.

The threaded portion on either one of the threaded surfaces formed on the inner peripheral surface of the post or the outer peripheral surface of the adjuster is formed only in a partitioned area partitioned from the peripheral surface, and when they slide axially relative to each other, the threaded portion of the partitioned area is flexed and deformed toward the opposite side of the contact surface due to contact pressure from the threaded portion (thread portion) on the other side. This configuration allows for axial sliding even when the mating threaded portions are in contact with each other, and when no axial sliding force is applied, the threaded portions can be held in a specific position by engagement.

The partitioned area is partitioned by gaps between the surroundings and the cutouts, except for some connection parts, and the partitioned area is deformed by the pressure of the opposing screw part when sliding, as described above, making it possible to slide. In addition, by making the size of the partitioned area 5mm to 12mm wide and 15mm to 25mm long, the contact area with the other screw part is appropriate for the bending deformation of the sliding means and for holding it in the set position. Note that if the size is larger than the range value, the contact area with the other screw part will be large, making it difficult to bend when sliding, and there is a concern that the resistance to sliding will be large and quick sliding will not be possible. On the other hand, if the size is smaller than the range value, the contact area between the support and adjuster will be small, so the screw part will not have enough screw-in holding force, making the position fixation unstable, and there is a concern that it may become misaligned during use.

The peripheral surface that forms the partition area is configured with multiple rows of ridges protruding from the partition area, so the contact surface with the threaded portion that forms the peripheral surface on the other side is small, consisting only of the threaded portion of the partition area and the ridge surface, which reduces resistance when sliding and allows for smooth operation.

By forming the screw part of the partition area into a sawtooth shape, for example, the sliding means can only move in the extension direction, preventing the adjuster from accidentally sliding in the contraction direction when the device is held by placing it on the body surface. In addition, the rotating means allows movement in both directions, making it possible to fine-tune the position.

When inserting a puncture needle into a specific area inside the body using image data such as CT scans as an indicator, the puncture needle guide device is used to insert the needle accurately into the target area without exposing the examiner to X-rays. The puncture needle guide device can be set on the body surface with easy and quick height adjustment using a support and adjuster.

1 is an overall configuration diagram of a puncture needle guide device according to an embodiment of the present invention; 3A to 3C are a front view, a top view, and an enlarged view of a portion (circled portion) of the guide instrument body of the embodiment. 1A is a cross-sectional view of a support portion of the guide device body of the embodiment as viewed from the right side, and FIG. 1B is an enlarged cross-sectional view of a portion (circled portion). FIG. 4 is a diagram showing the configuration of an adjuster of the puncture needle guide device of the above embodiment. 4 is a cross-sectional view showing a state in which a support and an adjuster of the puncture needle guide device of the embodiment are connected, and an enlarged view of a part (circled portion) thereof. FIG. FIG. 2 is an explanatory diagram showing a situation in which the puncture needle guide device of the above embodiment is used on a subject.

A puncture needle guide device according to an embodiment of the present invention will be described in detail with reference to the drawings. The device of this embodiment is a guide device for accurately inserting a puncture needle into a target site inside a subject's body, and is a guide device that can prevent the examiner from being exposed to X-rays by setting the insertion operation part of the puncture needle outside the X-ray radiation area, even when the puncture operation is performed while checking CT images in real time.

1 shows the overall configuration of the puncture needle guide device of this embodiment. This puncture needle guide device is basically composed of a guide part 11 having an insertion hole 111 as a passage for guiding the puncture needle 9 to a preset insertion position, a support 13 as a grip part of the device standing upright almost parallel to the guide part 11 with a predetermined interval, a guide device body 10 consisting of a beam 14 connecting the guide part 11 and the support 13, and an adjuster 20 arranged coaxially with the support 13 and capable of changing the protruding length from the support 13. In this embodiment, the guide part 11 is configured with a separable holding plate 12 that divides the insertion hole 111 into two in the axial direction and is detachable by a set screw 122, so that after puncturing with the puncture needle using this guide device, the guide device can be removed from the body surface while leaving the inserted needle tube, and by clamping and fixing the puncture needle from both sides, it is possible to accommodate a wide range of needle tubes with different outer diameter sizes. In this embodiment, the main body of the guide section 11, the support pillars 13, and the beams 14 are integrally molded from ABS resin as the guide instrument main body 10.

FIG. 2 shows a top view (A), a front view (B), and an enlarged view (C) of the circled portion of the front view of the guide device body of the above-mentioned embodiment, and FIG. 3 shows a cross-sectional view (A) of the right side view, and an enlarged view (B) of the circled portion of the cross-sectional view.
The guide instrument body 10 is composed of the guide portion 11 body, the support pillars 13, the beams 14, and the holding plate 12 which is detachable from the guide portion 11 body, which are integrally molded as described above.

The guide section 11 is formed as a column with an insertion hole 111 for inserting the puncture needle 9 or the guide needle 8 that guides the insertion passage of the puncture needle 9 at a site set in the X-ray irradiation area 7 in the gantry of the CT device, and the guide section 11 body and the holding plate 12 are configured to be freely attached and detached in such a manner that the insertion hole 111 is divided into two in the axial direction. Then, the set screw 122 provided on the holding plate 12 is tightened into the screw hole 112 provided on the guide section 11 body, and the puncture needle 9 or the guide needle 8 inserted in the insertion hole 111 is clamped from both sides and held in a specific position. In this way, due to the detachable configuration, it is possible to remove the guide device after inserting the puncture needle, leaving only the needle tube. In addition, in this example, a needle puncture line 121 that allows confirmation from the outside that the needle tube inserted into the insertion hole 111 is parallel to the CT X-ray slice plane is provided at a position along the path of the insertion hole 111 on the outer surface of the holding plate 12.

The support pillars 13 are formed in a columnar shape parallel to the guide portion 11 at an interval equal to the length of the beam 14 described below, which is set in an X-ray non-irradiated area outside the gantry of the CT scanner, and serve as a gripping portion when fixing the device to a predetermined position on the body surface. In addition, at the position where the device is gripped by the fingers, a gripping portion 131 with unevenness to prevent slipping is provided. In this example, the support pillars 13 are formed in a cylindrical rectangular shape, and the gripping portions 131 are provided at the lower positions of the opposing sides of the outer periphery of the device (close to the side where the adjuster 20 is connected).

A partitioned portion is provided on a portion of the inner peripheral surface of the support 13, protruding from the peripheral surface, and the surface of the partitioned portion is formed as a convex thread 132 that becomes a female thread that screws into a male thread provided on the outer peripheral surface of the adjuster 20 described below. In addition, the inner peripheral surface is formed with multiple rows of axially extending protrusions 133 (in this example, each corner portion formed into a cylindrical rectangle and the three sides excluding the side with the convex thread 132 at the middle portion of each side, for a total of seven rows), and the diameter formed by the convex thread 132 and the multiple protrusions 133 matches the outer diameter of the adjuster 20 (thread portion), and the support 13 and the adjuster 20 are held and rotated by the screw thread engagement. In this example, the partition is provided at a lower position (close to the side where the adjuster 20 is connected) on one of the inner circumferential surfaces (one side of the side) of the rectangular support 13, at a position that corresponds to the rear surface of the gripping section 131. By providing the partition on the rear surface of the gripping section 131 in this manner, the screw threaded portion is pressed from the outside when gripped, preventing misalignment of the support 13 and the adjuster 20. In this example, the size of the partition is 9 mm in width in the circumferential direction and 20 mm in length in the axial direction, but it may be in the range of 5 mm to 12 mm in width and 15 mm to 25 mm in length that does not cause inconvenience in the operation of the device.

The convex screw 132 formed in the partitioned portion of the support 13 is partitioned by protruding from the inner peripheral surface toward the inner side as described above, but the periphery that divides the partitioned portion has gaps as cutouts 134 on the lower side and both sides, except for the connection portion with the support at the upper side, and is formed so that only the partitioned portion bends slightly inward and outward. This bending deformation allows the support 13 and the adjuster 20 to slide axially.

The shape of this convex screw 132 is formed like a sawtooth with an inclined surface facing upward, which allows the adjuster 20 to slide relative to the support 13 only in the extension side and restricts sliding in the shortening side.

The beam 14 is a beam-shaped connecting part that connects the guide part 11 and the support pillar 13 at a distance from each other, which is set from the X-ray irradiation area inside the CT device gantry to the X-ray non-irradiation area outside the gantry to prevent the examiner from being exposed to X-rays. In this example, the beam 14 connects the upper side of the guide part 11 to the lower side of the support pillar 13, and is set to a length of approximately 100 mm in consideration of radiation protection and operability.

FIG. 4 shows a configuration diagram of the adjuster of this embodiment, and FIG. 5 shows (A) a cross-sectional view of the state in which the support and the adjuster are connected, and (B) an enlarged cross-sectional view of the circled portion of the cross-sectional view.
The adjuster 20 is a cylindrical body that is attached coaxially to the support 13 of the guide instrument main body 10 so that the length of protrusion from the support 13 can be changed. The adjuster 20 is an operating grip part for adjusting the protrusion length, and is composed of a leg 22 with a body surface abutment part 221, and an adjuster main body equipped with a male thread-shaped adjustment screw 21 that serves as a connecting screw-type part with the support 13.

The leg 22 is made up of a cone with a body surface contact part 221 at its tip to prevent slipping on the body surface when it is set on the body surface and to facilitate maneuverability for adjusting the height and inclination of the device, and a cylindrical part that serves as a grip for rotating the device with the support 13, and the cylindrical part is formed in a top shape with an outer diameter larger than the adjuster body.

The adjustment screw 21 of the adjuster body is screwed into the convex thread 132 of the support 13, and is set to an outer diameter (diameter of the thread thread) that fits the protrusion 133 provided on the inner peripheral surface of the support 13. The shape of the adjustment screw 21 is formed like a sawtooth with an inclined surface facing downward, and when the inclined surface of the convex thread 132 is screwed into a screw that forms a sawtooth shape facing upward, the contact surfaces become inclined surfaces in the extension direction from the support 13, allowing sliding movement, and the contact surfaces become corners in the contraction direction, restricting sliding movement. In this example, the adjustment screw 21 portion is cylindrical, but it may be a solid cylinder.

The support 13 and adjuster 20 of the guide instrument body 10 are screwed together with the convex screw 132 and the adjustment screw 21, allowing the length of the adjuster 20 protruding from the support 13 to be freely adjusted. This allows the guide portion 11 of the guide instrument body 10, i.e., the puncture needle inserted into the guide portion 11, to be set parallel to the cross section of the CT image, for example, perpendicular to the body surface, on a non-flat body surface, and as a result, the puncture needle can be accurately inserted into the puncture target site 6.

In addition, by forming the female thread of the convex screw 132 and the male thread of the adjustment screw 21 into a sawtooth shape with inclined surfaces on opposite sides as described above, and by providing notches 134 on three sides around the partitioned area of the convex screw 132 of the support 13, the partitioned area can be flexibly deformed, allowing for rapid sliding movement in the extension direction, restriction of movement in the contraction direction, and temporary rotational movement in both directions. This allows the adjustment of the protruding length of the adjuster 20 from the support 13 to be set quickly and accurately, and the set position can be maintained.

In addition, in this device, the height of the guide section 11 is configured to be lower than the height of the support 13 and adjuster 20 that stand upright in parallel with the guide section 11. This allows a large spatial distance to be secured between the subject's body surface when the guide device is used inside a CT gantry, which gives the examiner a wider field of view and makes it easier to observe the subject's body surface and perform procedures.

FIG. 6 shows a situation in which the puncture needle guide device of the present invention is used on a subject.
In order to obtain image data of the CT tomographic plane (slice plane, scanner plane), the subject 3 is placed on the table 4 of the CT device. The examiner (not shown) percutaneously punctures the target site 6 from the epidermis 31 of the chest or abdomen of the subject 3. The puncture needle guide device is used to percutaneously insert the puncture needle 9 into the target site 6 accurately. The puncture needle guide device is placed on the epidermis 31 of the chest or abdomen of the subject 3 located at the X-ray radiation unit 7 of the gantry 5. The examiner confirms the target site 6, determines the insertion position, depth, and direction (puncture route) of the puncture needle 9, and fixes the puncture needle guide device in accordance with the puncture line. Immediately, while checking the tip of the puncture needle 9 under the image, it is inserted through the epidermis 31 so as to reach the target site 6 accurately, and is punctured while being held parallel to the cross section of the CT image. The needle puncture may be performed by first setting the guide needle 8 at the insertion position of the epidermis 31 using a puncture needle guide device, or by shallowly puncturing the epidermis 31. Next, the puncture needle 9 is inserted through the guide needle 8 toward the target site 6. The examiner uses the inserted puncture needle 9 to perform a predetermined procedure, such as drug injection or biopsy. In this case, the examiner is particularly required to reproduce the puncture route determined on the image, and by using the puncture needle guide device of the embodiment of the present invention, the target site can be punctured accurately.

Next, an example of the procedure for using the puncture needle guide device of the embodiment of the present invention on a subject will be described. Note that this example uses the needle puncture procedure in real-time CT fluoroscopic images as an indicator.

Step 1. Prior to needle puncture, the target site 6 and the puncture route are confirmed under CT fluoroscopy, the optimal cross section for puncture is determined, and the puncture point is marked.
Step 2. The introduction needle 8 and the puncture needle 9 are mounted in the insertion hole 111 of the guide part 11, and the position of the puncture needle 9 when it is advanced a previously measured distance is marked.
Step 3. After local anesthesia and skin incision, the guide instrument is placed on the body surface 31, and the length of the adjuster 20 protruding from the support 13 is adjusted by the sliding and rotating operations described above, referring to the laser marker that is standard equipment on the CT, so that the laser marker hits the entire puncture line 121 provided on the holding plate 12 of the guide instrument. By aligning the laser marker with the puncture line 121 in this way, the entire puncture needle 9 can always be kept within the CT cross section (X-ray irradiation area 7).
Step 4. Have the subject hold his/her breath, start CT fluoroscopy, confirm that the target site 6 is within the CT fluoroscopic section, and slowly adjust the inclination of the entire guide device while watching the CT fluoroscopic image to point the puncture needle 9 toward the target site 6. At this time, a black linear artifact is seen from the needle tip 82 or 92, and by making sure that this overlaps with the target site 6, more accurate puncture is possible.
Step 5: Turn off the CT fluoroscopy and advance the puncture needle 9 the measured distance.
Step 6. Restart the CT fluoroscopy and confirm that the needle tip 92 has reached just before the target site. If the needle tip 92 has fallen out of the CT section, move the table 4 under CT fluoroscopy and confirm the positional relationship between the needle tip 92 and the target site 6.
Step 7: After the tip 92 of the puncture needle 9 has been confirmed, the CT fluoroscopy is turned off and the intended procedure (biopsy, etc.) is performed.
Step 8: It is confirmed by CT fluoroscopy that the needle tip 92 is in the target area, and the needle 9 is removed.

In the embodiment of the present invention, when the puncture needle guide device is set on the body surface, first, adjustment is performed by any one of the following operations or a combination of operations.
1. The blade tip 82 of the guide needle 8 set in the guide unit 11 is aligned with the insertion position in accordance with the puncture position and puncture route previously set based on the CT fluoroscopic image.
2. In order to align the puncture route with the CT slice plane (slice plane, scan plane), the amount of protrusion of the adjuster 20 protruding from the support 13 is adjusted.
3. In order to align the angle at which the target position 6 can be reached along the pre-planned puncture route, the entire guide device is tilted left and right within the range of the CT slice plane to align it.
By performing the above steps 1 to 3, the puncture route can be set very easily and accurately.

According to the guide device of the embodiment of the present invention, the puncture needle 9 is inserted using the introducer needle 8, so the puncture direction of the puncture needle 9 is regulated, and the puncture needle 9 is also protected by the introducer needle 8, making it possible to accurately puncture the target site and reducing bending during puncture even with a thin needle tube.

REFERENCE SIGNS LIST 10 Guide instrument body 11 Guide portion 111 Insertion hole 112 Screw hole 12 Retaining plate 121 Puncture line 122 Set screw 13 Support 131 Grip processing portion 132 Convex screw 133 Protrusion 134 Notch portion (gap)
REFERENCE SIGNS LIST 14 Beam 20 Adjuster 21 Adjustment screw 22 Leg 221 Body surface contact portion 3 Human body 31 Body surface 4 Table 5 Gantry 6 Target portion 7 X-ray radiation area 8 Guide needle 81 Guide needle base 82 Guide needle tip 9 Puncture needle 91 Puncture needle base 92 Puncture needle tip

Claims (7)

A guide device for inserting a puncture needle into a specific position in a body, the guide device comprising: a guide section having a passageway for guiding the puncture needle to the insertion position; a support post serving as a gripping section of the device and disposed substantially parallel to the guide section at a predetermined distance; a beam connecting the guide section and the support post; and an adjuster including a body surface contact section disposed coaxially with the support post and capable of varying the length of protrusion from the support post;
The inner peripheral surface of the support and the outer peripheral surface of the adjuster are formed with threaded portions that screw into each other, and either one of the threaded portions is formed only in a partitioned area that is a part of the inner peripheral surface or the outer peripheral surface and is partitioned from the surroundings, and the threaded portion of the partitioned area is formed so as to be able to be flexibly deformed outwardly or inwardly by contact and pressure from the threaded portion formed on the peripheral surface of the other side,
The puncture needle guide device is characterized in that it comprises, as a means for adjusting the protruding length of the adjuster from the support, a sliding means for moving the adjuster in a parallel direction along the axis of the support as a result of the partition portion being flexibly deformed, and a rotating means for moving the adjuster in a circumferential direction as the screw portion is screwed into the sliding means. The puncture needle guide device of claim 1, in which the sliding means can slide only in the extension direction in which the adjuster protrudes from the support, and sliding in the shortening direction in which the adjuster is stored in the support is restricted, and the rotating means can move in both the extension and retraction directions. The puncture needle guide device according to any one of claims 1 to 2, wherein the partitioned area is partitioned from the surroundings by a gap formed by a cut, except for a connection part that connects to the inner or outer peripheral surface. The puncture needle guide device according to any one of claims 1 to 3, wherein the partitioned area is formed to have a circumferential width of 5 mm or more and 1 mm or less and an axial length of 15 mm or more and 25 mm or less. The puncture needle guide device according to any one of claims 1 to 4, wherein the partitioned portion is formed by protruding from the surrounding surface, and the peripheral surface including the partitioned portion has multiple rows of ridges that protrude from the surrounding surface and extend in the axial direction and are the same height as the valley height of the threaded portion formed in the partitioned portion, and the outer or inner diameter formed by the partitioned portion and the multiple ridges matches the inner or outer diameter of the threaded portion formed on the other surface. The puncture needle guide device according to any one of claims 1 to 5, wherein the threaded portion provided in the partitioned area is formed in a sawtooth shape. The puncture needle guide device according to claim 1 , wherein the partitioned area is formed on the inner surface of a support post formed in a cylindrical shape.

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