JP4536631B2 - Spacer - Google Patents

Description

  The present invention relates to a spacer.

  For example, as a treatment for cervical spondylotic myelopathy, posterior longitudinal ligament ossification, yellow ligament ossification, intervertebral disc herniation, etc., a median longitudinal split cervical vertebral laminoplasty is performed.

  In midline longitudinal split laminoplasty, the midline (center) of the vertebral arch and spinous process is cut, and the vertebral arches on both sides are opened like a hinge with the midline as the boundary. Enlarge the tube. At this time, a spacer is inserted into a gap formed by cutting a vertebral arch or spinous process (see, for example, Patent Document 1).

  This spacer is used by being inserted into the gap so that the narrow portion is on the spinal canal (vertebral foramen) side.

  However, in some cases, sufficient fusion does not occur at the contact portion between the cut end of the vertebral arch or spinous process and the spacer, and it may not be fixed securely.

JP 2003-79648 A

  An object of the present invention is to provide a spacer that can be more reliably and quickly fixed to a vertebral arch or spinous process.

Such an object is achieved by the present inventions (1) to (5) below.
(1) a spacer used to expand a spinal canal by inserting into a gap formed by cutting and opening a vertebral arch or spinous process;
A pair of abutment surfaces that respectively abut against the cut ends of the vertebral arch or spinous process in a state where at least a portion is inserted into the gap, and a flat located on the opposite side of the spinal canal A main body portion including a rear surface ,
In the main body portion, an opening is formed in each of the contact surfaces, and a storage portion formed for storing the own bone; and
A spacer having a posterior opening formed on the posterior surface by opening at least a part of the storage portion and capable of returning the separated spinous process back .

Thereby, bone fusion can be caused between the cut end and the autologous bone, and the spacer can be more reliably and early fixed to the vertebral arch or spinous process.
As a result, when the separated spinous process is returned to its original position as a surgical technique, early fusion between the spinous process and the spacer can be achieved.

(2) the housing unit, the spacer according to the above (1) from one of the abutment surfaces extends through the other of the abutment surface.

  Thereby, the volume of a storage part can be fully enlarged, without enlarging a main-body part. As a result, a sufficient amount of autologous bone that can be expected for early bone fusion with the cut end can be stored in the storage unit.

( 3 ) The spacer according to (1) or (2) , wherein the storage part is divided by a partition part.
Thereby, the mechanical strength on the rear side of the spacer can be improved.

( 4 ) The spacer according to any one of (1) to ( 3 ), wherein a ratio of the storage portion in the main body portion is 5 to 50 vol%.

  Thereby, it is possible to secure a sufficient space for storing the own bone while preventing the mechanical strength of the spacer from being lowered.

( 5 ) The spacer according to any one of (1) to ( 4 ), wherein an area of the opening of the storage portion is 10 to 90% of an area of the contact surface.

  As a result, it becomes possible for the osteoblasts to move more smoothly from the storage part to the cutting end part or from the cutting end part to the storage part, and bone fusion between the autologous bone and the cutting end part occurs earlier. It will be.

  According to the present invention, since the storage portion for storing the autologous bone is provided, it is possible to cause bone fusion between the cut end and the autologous bone, and the spacer can be more securely attached to the vertebral arch and spinous process. And it becomes possible to fix early.

Hereinafter, the spacer of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
FIG. 1 is a view showing a first embodiment of a spacer of the present invention ((a) perspective view, (b) side view), and FIGS. 2 to 5 are respectively a median longitudinal split type laminoplasty. It is a figure for explaining in order.

<Medium longitudinal split-type enlarged laminoplasty>
First, with reference to FIG. 2 to FIG. 5, the median longitudinal split type laminoplasty will be described. 2 to 5, the upper side is the dorsal side, and the lower side is the ventral side.

  As shown in FIG. 2, the vertebra 100 includes a vertebral body 110, a vertebral arch 120 that extends behind the vertebral body 110 (upper side in FIG. 2) and forms a spinal canal (vertebral foramen) 140, And a spinous process 130 protruding backward from the central portion.

  [1] First, as shown in FIG. 2, the spinous process 130 in the vertebra 100 is separated (cut) from the vertebral arch 120 at a cutting line 131.

  [2] Next, as shown in FIG. 3, the central portion (midline portion) of the vertebral arch 120 is cut using, for example, an air drill.

  Further, grooves 121a and 121b are formed on the outer side of the root portion of the vertebral arch 120 with the median plane 200 as a boundary, for example, using an air drill or the like.

  The depths of the grooves 121a and 121b are set such that only the outer plate is cut and the inner plate is not cut. The portions where the grooves 121a and 121b are formed are hinge portions (hinges) 122a and 122b.

  [3] Next, as shown in FIG. 4, the vertebral arch 120 is rotated around the hinges 122a and 122b, and the cut portion of the vertebral arch 120 is expanded. Thereby, the gap 150 is formed.

  If necessary, the cut ends 120a and 120b facing the gap 150 of the vertebral arch 120 are shaped.

  [4] Next, as shown in FIG. 5, the spacer 1 of the present invention is inserted into the gap 150. Thus, an enlarged vertebral arch 160 is formed by the patient's vertebral arch 120 and the spacer 1.

  The spinous process 130 separated in [1] may be returned to the center (midline), fixed to the spacer 1 with a thread or the like, and bone fusion may be achieved. It may be used.

  Further, the spinous process 130 may be cut along the median plane 200 in the step [2] without separating the spinous process 130 from the vertebral arch 120.

<Spacer>
Next, the spacer 1 of this invention is demonstrated with reference to FIG. 1 and FIG.

  In the following description, unless otherwise specified, the direction is specified based on the state in which the spacer 1 is inserted (attached) into the treatment site (gap 150) of the patient. That is, the patient's ventral side (vertebral canal 140 side) is called “front”, the dorsal side (opposite to the spinal canal 140) is called “rear”, the patient's head side is “up”, and the patient's leg side is “down”. "

  As shown in FIGS. 1 and 5, the spacer 1 includes a main body portion 2 partially inserted into the gap 150, and an engaging portion 3 that engages the rear side of the cut ends 120 a and 120 b of the vertebral arch 120. have.

As shown in FIG. 5, the main body 2 has a substantially trapezoidal shape when viewed from above (or from below).
Further, the front surface 11 of the main body 2 is configured by a curved concave surface, and the spinal canal 140 can be enlarged larger (wider) to prevent compression of the spinal nerve.

  Further, the pair of side surfaces 12 of the main body 2 constitute contact surfaces with which the cut end portions 120a and 120b of the vertebral arch 120 abut in a state of being inserted into the gap 150, respectively.

  A substantially U-shaped groove 4 is formed on the rear side of the main body 2 so as to be substantially parallel to the front surface 11.

  The groove 4 opens to each side surface 12 and opens to the rear of the main body 2 over its entire length.

  This groove | channel 4 comprises the accommodating part which accommodates a self-bone. When the spacer 1 is inserted into the gap 150, the autologous bone is housed in the groove 4 so that osteoblasts proliferate from the cut ends 120a and 120b and the autologous bone to produce new bone. As a result, bone fusion occurs between the cut ends 120a and 120b and the autologous bone, and the spacer 1 can be fixed to the vertebral arch 120 more reliably and early.

  Further, as in the present embodiment, when the storage portion for storing the autologous bone is configured to penetrate from the one side surface 12 to the other side surface 12, the volume of the storage portion is increased without enlarging the main body portion 2. Can be large enough. As a result, a sufficient amount of autologous bone can be stored in the storage unit so as to expect early bone fusion with the cut ends 120a and 120b.

  Here, as the autologous bone, for example, a spinous process 130 removed in the median longitudinal split-type laminoplasty, a bone section (bone fragment) collected from a bone (for example, pelvis) or the like at another site, or the like is used. be able to.

  These bone sections may be stored in the grooves 4 as they are, but are preferably used in a crushed state (bone chips).

  Further, it is preferable that the autologous bone is stored and used in the groove 4 so as to be exposed from both ends of the groove 4. Thereby, an autologous bone and the cutting | disconnection edge part 120a, 120b come to contact directly, and an earlier bone fusion can be aimed at.

  The ratio of the groove (housing part) 4 to the main body part 2 is preferably about 5 to 50 vol%, more preferably about 20 to 40 vol%. Thereby, it is possible to sufficiently secure a space for storing the own bone while preventing the mechanical strength of the spacer 1 from being lowered.

  Further, the area of the opening of the groove (housing part) 4 in the side surface (contact surface) 12 is preferably about 10 to 90% of the area of the side surface 12, and more preferably about 20 to 70%. This allows the osteoblasts to move more smoothly from the groove 4 to the cut ends 120a, 120b, or from the cut ends 120a, 120b to the groove 4, and the autologous bone and the cut ends 120a, 120b. And bone fusion will occur earlier.

  Further, if the storage part is configured to open to the rear of the main body part 2 as in the groove 4, for example, when returning the separated spinous process 130 to the original position as a surgical procedure, the spinous process is performed. As a result, the spinous process 130 can be reliably and quickly fixed to the vertebral arch 120 via the spacer 1.

  In addition, although the shape of the groove | channel 4 was U shape in the example of illustration, it may be U shape, V shape, etc. other than this, for example.

  Further, as shown in FIG. 1, a through-hole penetrating the main body 2 in the left-right direction (a direction substantially perpendicular to the front-rear direction) is provided on the front side of the groove 4 of the main body 2 (independently). 5 is formed. A thread 300 as a fixing member can be inserted into the through hole 5.

  As shown in FIG. 5, through-holes 123a and 123b are formed in the cut ends 120a and 120b of the vertebral arch 120, respectively, and a thread 300 is inserted and tied to the through-hole 5 and the through-holes 123a and 123b (sewn). ), The spacer 1 can be fixed to the vertebral arch 120. Thereby, it is possible to prevent the spacer 1 from being displaced with respect to the vertebral arch 120 early after the operation, and to more reliably cause bone fusion between the cut ends 120a and 120b and the autologous bone. Can do.

  Further, since the through hole 5 and the groove 4 are independent, that is, the through hole 5 and the groove 4 are not communicated with each other, the mechanical strength of the spacer 1 as a whole can be prevented from being lowered.

  In the configuration shown in FIG. 1, the cross-sectional shape of the through-hole 5 is substantially circular, but may be, for example, an ellipse, a rectangle, a square such as a square, a triangle, or the like.

  An engaging portion 3 is provided at a rear end portion of the main body portion 2. The engaging part 3 of the present embodiment is composed of four protrusions 31 protruding from the main body part 2 toward the side.

  When the spacer 1 is inserted into the gap 150, the four protrusions 31 come into contact with the rear sides of the cut end portions 120a and 120b, respectively. As a result, the spacer 1 is prevented from moving toward the spinal canal 140 and the spinal nerve can be reliably prevented from being compressed by the spacer 1, which is highly safe.

  Moreover, as shown in FIG. 5, it is preferable that the spacer 1 has a rounded corner (R-applied) over the whole. Thereby, it is possible to prevent the surrounding tissue from being damaged when the spacer 1 is inserted into the gap 150.

In such a spacer 1, the dimension of each part is set as follows, respectively.
The length of the spacer 1 in the front-rear direction (L in FIG. 1) is preferably about 5 to 10 mm, and more preferably about 5 to 7 mm.

The spacer 1 the horizontal length of the (main body portion 2) (Figure 1 during _{W 1)} is preferably about 6～23Mm, more preferably about 10～21Mm.

Also, the left-right direction of the length of the spacer 1 (main body part 2) (Figure 1 during _{W 2)} is preferably about 4～21Mm, more preferably about 6～18Mm.

  Moreover, it is preferable that the width | variety (w in FIG. 1) of the groove | channel 4 is about 1-6 mm, and it is more preferable that it is about 3-4 mm.

  Moreover, it is preferable that the depth (d in FIG. 1) of the groove | channel 4 is about 1-6 mm, and it is more preferable that it is about 3-4 mm.

  The average inner diameter (r in FIG. 1) of the through holes 5 is preferably about Φ0.5 to Φ5 mm, more preferably about Φ1 to Φ2 mm.

  Such a spacer 1 is preferably made of a ceramic material as a main material. Since the ceramic material is excellent in workability, in the manufacturing process of the spacer 1, it is easy to adjust its shape, size, etc. by cutting using a lathe, a drill or the like.

  Examples of the ceramic material include various materials, and bioceramics such as alumina, zirconia, and calcium phosphate compounds are particularly preferable. Among these, a calcium phosphate compound is particularly preferable as a constituent material of the spacer 1 because it has excellent biocompatibility.

  Examples of the calcium phosphate compound include apatites such as hydroxyapatite, fluorapatite, and carbonate apatite, dicalcium phosphate, tricalcium phosphate, tetracalcium phosphate, octacalcium phosphate, and the like. Species or a combination of two or more can be used. Of these calcium phosphate compounds, those having a Ca / P ratio of 1.0 to 2.0 are preferably used.

  Of such calcium phosphate compounds, hydroxyapatite is more preferable. Hydroxyapatite has an excellent biocompatibility because it has the same structure as the mineral main component of bone. Further, it is possible to expect the fusion between the spacer 1 itself and the cut ends 120a and 120b.

  Further, the porosity of the spacer 1 is preferably 70% or less, and more preferably 30 to 50%. By setting the porosity within this range, it is possible to smoothly enter osteoblasts into the spacer 1 while preventing the mechanical strength of the spacer 1 from being lowered, and to promote osteogenesis in the spacer 1. it can. As a result, in particular, when the spacer 1 is made of hydroxyapatite as a main material, it is possible to expect more reliable fusion between the spacer 1 itself and the cut ends 120a and 120b.

  As a constituent material of the spacer 1, in addition to the above ceramic material, a composite material of the ceramic material and a metal material having a low biological harm such as titanium can be used.

Such a spacer 1 can be manufactured as follows, for example.
Below, the case where the spacer 1 comprised with a ceramic material is manufactured is demonstrated to an example.

[A] First, a molded body having a shape corresponding to the shape of the target spacer 1 is manufactured.
This molded body is, for example, I: a method in which a slurry containing ceramic raw material powder is filled in a predetermined mold and molded, II: a method in which solid content is unevenly distributed to the slurry by precipitation or centrifugation, III : Slurry is put in a predetermined mold and dehydrated to leave the solid content in the mold. IV: Compression molding method (in the case of powder, compacting) V: Ceramic raw material powder and water paste It can be produced by various methods such as mixing, putting it in a mold and drying it.

  The slurry may contain secondary particles granulated in advance by a spray drying method or the like as a ceramic raw material powder.

  Moreover, the porosity of the spacer 1 obtained can be adjusted by adjusting whether or not a binder agent is added to the slurry, the amount of addition when added, the content of bubbles in the slurry, and the like.

  The obtained molded body is dried by, for example, natural drying, hot air drying, freeze drying, vacuum drying, or the like.

  In addition, the dimension of a molded object is set considering the shrinkage | contraction in baking of a post process with respect to the dimension of the spacer 1. FIG.

[B] Next, recesses to be the grooves 4 and the through holes 5 are formed in the molded body by, for example, machining such as cutting, cutting, grinding, and polishing.
In addition, since the hardness of the molded body is relatively low, machining by machining is easy.

  [C] Next, the molded body thus obtained is fired in, for example, a furnace. Thereby, the molded body is densified and sintered, and the spacer 1 is obtained.

<Second Embodiment>
Next, a second embodiment of the spacer of the present invention will be described.

  FIG. 6 is a view ((a) perspective view, (b) side view) showing a second embodiment of the spacer of the present invention.

  Hereinafter, the spacer 1 of the second embodiment will be described focusing on the differences from the spacer 1 of the first embodiment, and the description of the same matters will be omitted.

  The spacer 1 shown in FIG. 6 is the same as the spacer 1 shown in FIG. 1 except that the configuration of the groove 4 is different.

  That is, in the spacer 1 of the second embodiment, two bridge portions 6 are formed integrally with the main body portion 2 across the groove 4 at both end portions of the groove 4 and at the rear end portion of the main body portion 2. ing. Thereby, the groove | channel 4 has a part which does not open behind the main-body part 2 in a part of the longitudinal direction.

With such a configuration, the mechanical strength on the rear side of the spacer 1 can be improved.
In addition, the dimension of each part is the same as that of the spacer 1 of the said 1st Embodiment.

  The effect similar to the said 1st Embodiment is acquired also by the spacer 1 of such 2nd Embodiment.

<Third Embodiment>
Next, a third embodiment of the spacer of the present invention will be described.

  FIG. 7 is a diagram ((a) perspective view, (b) side view) showing a third embodiment of the spacer of the present invention.

  Hereinafter, the spacer 1 of the third embodiment will be described focusing on the differences from the spacer 1 of the first embodiment, and the description of the same matters will be omitted.

  The spacer 1 shown in FIG. 7 is the same as the spacer 1 shown in FIG. 1 except that the storage portion for storing the own bone and the configuration of the engaging portion 3 are different.

  That is, in the spacer 1 of the third embodiment, the storage portion is configured by the through hole 7 that penetrates the both side surfaces (contact surfaces) 12 but does not open to the rear of the main body portion 2.

  In the configuration shown in FIG. 7, the cross-sectional shape of the through-hole 7 is substantially circular, but may be, for example, an ellipse, a rectangle, a square such as a square, a triangle, or the like.

  The engaging portion 3 is composed of two plate-like flanges 32 protruding from the main body portion 2 toward the side at the rear end portion of the main body portion 2.

With such a configuration, the mechanical strength on the rear side of the spacer 1 can be improved.
In addition, the dimension of each part is the same as that of the spacer 1 of the said 1st Embodiment.

  The effect similar to the said 1st Embodiment is acquired also by the spacer 1 of such 3rd Embodiment.

<Fourth embodiment>
Next, a fourth embodiment of the spacer of the present invention will be described.

  FIG. 8 is a view ((a) perspective view, (b) side view) showing a fourth embodiment of the spacer of the present invention.

  Hereinafter, the spacer 1 of the fourth embodiment will be described focusing on the differences from the spacer 1 of the first and third embodiments, and the description of the same matters will be omitted.

  The spacer 1 shown in FIG. 8 is the same as the spacer 1 shown in FIG. 7 except that the overall shape is different.

That is, in the spacer 1 of the fourth embodiment, a portion 8 having a spinous process shape is formed integrally with the main body 2 at a substantially central portion of the rear surface of the main body 2. Thereby, the patient's appearance after the operation is made more natural, and an effect of being excellent in aesthetics can be obtained.
In addition, the dimension of each part is the same as that of the spacer 1 of the said 1st Embodiment.

  The effect similar to the said 1st and 3rd embodiment is acquired also by the spacer 1 of such 4th Embodiment.

<Fifth Embodiment>
Next, a fifth embodiment of the spacer of the present invention will be described.

  FIG. 9 is a view ((a) perspective view, (b) side view) showing a fifth embodiment of the spacer of the present invention.

  Hereinafter, the spacer 1 of the fifth embodiment will be described focusing on the differences from the spacer 1 of the first embodiment, and the description of the same matters will be omitted.

  The spacer 1 shown in FIG. 9 is the same as the spacer 1 shown in FIG. 1 except that the configuration of the groove 4 is different.

  That is, in the spacer 1 of the fifth embodiment, the groove 4 has a first portion 41 opened on one side surface 12 and a first portion 41 opened on the other side surface 12 by the partition wall portion 9 at a substantially central portion in the longitudinal direction. It is divided into two portions 42.

  With such a configuration, the mechanical strength on the rear side of the spacer 1 can be improved. Moreover, the effect that the handling at the time of an operation is made easy is acquired by making the partition part 9 function as a holding part.

In addition, the dimension of each part is the same as that of the spacer 1 of the said 1st Embodiment.
In addition, one or a plurality of through holes may be formed in the partition wall 9.

  The effect similar to the said 1st Embodiment is acquired also by the spacer 1 of such 5th Embodiment.

  In the present embodiment, both the first portion 41 and the second portion 42 are configured to open to the rear of the main body 2, but one or both of these are disposed to the rear of the main body 2. The structure which does not open | release may be sufficient.

  As mentioned above, although the spacer of this invention was demonstrated based on embodiment of illustration, this invention is not limited to this, Each structure can be substituted by the arbitrary things which can exhibit the same function. Or an arbitrary configuration can be added.

  For example, in the present invention, any two or more configurations shown in the first to fifth embodiments may be combined. For example, in the spacer of the fifth embodiment, a portion having a spinous process shape described in the fourth embodiment can be provided on the rear end surface of the partition wall.

  Moreover, in the spacer of the said embodiment, although all showed about the structure provided with an engaging part, you may abbreviate | omit an engaging part in the spacer of this invention.

  In addition, in the spacers of the above-described embodiment, the insertion portion has a substantially trapezoidal shape in plan view, but the spacer of the present invention has a columnar shape such as a columnar shape or a quadrangular prism shape. It may be an eggplant.

It is a side view which shows 1st Embodiment of the spacer of this invention. It is a figure for explaining the midline longitudinal split type laminoplasty step by step. It is a figure for explaining the midline longitudinal split type laminoplasty step by step. It is a figure for explaining the midline longitudinal split type laminoplasty step by step. It is a figure for explaining the midline longitudinal split type laminoplasty step by step. It is a side view which shows 2nd Embodiment of the spacer of this invention. It is a side view which shows 3rd Embodiment of the spacer of this invention. It is a side view which shows 4th Embodiment of the spacer of this invention. It is a side view which shows 5th Embodiment of the spacer of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spacer 11 Front surface 12 Side surface 2 Main body part 3 Engagement part 31 Projection 32 Flange 4 Groove 41 1st part 42 2nd part 5 Through-hole 6 Bridge part 7 Through-hole 8 Part which makes spinous process shape 100 Vertebral 110 110 Vertebral body 120 vertebral arch 120a, 120b cutting end 121a, 121b groove 122a, 122b hinge part 123a, 123b through hole 130 spinous process 131 cutting line 140 spinal canal 150 gap 160 enlarged vertebral arch 200 midline 300 thread

Claims (5)

A spacer used to expand the spinal canal by inserting into a gap formed by cutting and opening a vertebral arch or spinous process,
A pair of abutment surfaces that respectively abut against the cut ends of the vertebral arch or spinous process in a state where at least a portion is inserted into the gap, and a flat located on the opposite side of the spinal canal A main body portion including a rear surface ,
In the main body portion, an opening is formed in each of the contact surfaces, and a storage portion formed for storing the own bone; and
A spacer having a posterior opening formed on the posterior surface by opening at least a part of the storage portion and capable of returning the separated spinous process back .   The spacer according to claim 1, wherein the storage portion penetrates from one contact surface to the other contact surface.   The spacer according to claim 1, wherein the storage part is divided by a partition part.   The spacer according to any one of claims 1 to 3, wherein a ratio of the storage portion in the main body portion is 5 to 50 vol%.   The spacer according to any one of claims 1 to 4, wherein an area of the opening of the storage portion is 10 to 90% of an area of the contact surface.

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