Template manufacturing method

Abstract

To provide a template that teaches an extent of the curve of a rod by which a correction effect optimum for a patient can be obtained to operation staff members including an operator at a stage prior to the installation in a body without depending on experience, intuition, etc. of the operation staff members including the operator.SOLUTION: A template 10 teaches an extent of the curve of an overall rod corresponding to an angle of shape of the pelvis unique to a patient to operation staff members including an operator at a stage prior to the installation of the rod in a body. By the rod having an optimum curve taught by the template 10, correction and fixing can be performed for spinal deformity without depending on experience, intuition, etc. of the operation staff members including an operator, thereby achieving a correction effect optimum for the patient.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention is used in the stage prior to placing a rod, which is attached to each vertebra of the spinal column and configured as an implant material in the patient's body, and indicates the degree of curvature of the rod. Templates This relates to a manufacturing method of the above. [Background technology]

[0002] Conventionally, surgical treatments for stabilizing the spine, such as by making a large incision in the midline of a patient's back and inserting pedicle screws and rods through the incision and attaching them to the spine, have been performed. In such spinal deformity correction and fixation procedures, rods made of biocompatible materials such as titanium alloys and cobalt-chromium alloys are held in place by pedicle screws threaded into the pedicles, thereby correcting and fixing the spine. The rods are usually manually bent during surgery, i.e., immediately before being attached to the pedicle screws, using a surgical instrument such as a bender. Furthermore, even before the rods are firmly attached to the pedicle screws (temporarily attached), the surgeon may manually fine-tune the curvature of the rods as needed.

[0003] The shape of the bent rod (rod curvature) largely determines the state of the spine after correction. Therefore, rod curvature is an important factor in spinal deformity correction and fixation surgery. In previous spinal deformity correction and fixation surgery, the surgeon or surgical staff appropriately bent a straight rod using specialized surgical instruments during surgery. However, the degree of curvature of the entire rod, i.e., the direction and angle of curvature, depended on the experience and intuition of the surgeon and surgical staff, and could vary slightly depending on the surgeon and surgical staff, making it difficult to achieve the optimal correction effect for the patient. In other words, in the past, there was no way to instruct the surgeon or surgical staff on the degree of curvature of the entire rod that would achieve the optimal correction effect for the patient before placing the rod inside the patient's body.

[0004] Recently, minimally invasive surgery has been adopted, in which pedicle screws and rods are inserted percutaneously (through a few small incisions) into the patient's back and fixed to each vertebra to stabilize the spine. Compared to procedures requiring large back incisions, percutaneous spinal stabilization offers many advantages to patients, including reduced blood loss, shorter surgery time, and reduced surgical site infections. In such minimally invasive surgery, the aforementioned issue of rod curvature becomes more pronounced and becomes a major problem. This is because, as with procedures requiring large back incisions, even in such minimally invasive surgery, the rods are appropriately bent by the surgeon and other surgical staff using specialized surgical instruments before being inserted into the patient's body. However, once the bent rods are inserted percutaneously, it is difficult to easily adjust the curvature of the rods.

[0005] Furthermore, procedures that involve large incisions in the patient's back involve releasing all of the muscles and ligaments attached to the vertebral tissue, opening the surgical field, and correcting the spinal alignment using a spinal stabilization system (including pedicle screws and rods). This reduces the load on the rods, resulting in a smaller amount of deformation of the rods after placement compared to their pre-placement state. In contrast, percutaneous procedures do not release the muscles and ligaments attached to the vertebral tissue, but instead use a spinal stabilization system to correct the spinal alignment. This places a greater load on the rods, resulting in a larger amount of deformation after placement compared to their pre-placement state. Therefore, in percutaneous procedures, the experience and intuition gained from back incision procedures regarding the degree of rod curvature before placement is completely useless. Therefore, even in percutaneous procedures, the precise degree of rod curvature before placement becomes even more important.

[0006] Patent document 1 discloses an instrument for bending a surgical rod, comprising a handle forming a receiving area for receiving a surgical rod, a lever rotatably connected to the handle, and a template rod holder configured to hold a template rod having a bent shape that can be used as a template for bending a surgical rod around a bending axis, the template rod holder being attached to one of the handle and the lever at a position adjacent to the receiving area. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2021-519171 Summary of the Invention [Problem to be solved by the invention]

[0008] However, while the surgical rod bending instrument described in Patent Document 1 is equipped with a template rod holder for holding a template rod, this template rod is simply used to locally bend the surgical rod and does not instruct the surgeon or surgical staff on the overall curvature direction or exact angle of the surgical rod that will provide the optimal correction effect for each patient. In other words, the template rod described in Patent Document 1 does not instruct the surgeon or surgical staff on the optimal curvature of the entire surgical rod based on the patient's specific pelvic morphological angle (PI). Therefore, even if a surgical rod curved along the template rod is used to correct and fix a spinal deformity, it is difficult to achieve the optimal correction effect for each patient.

[0009] In short, even with the template rod described in Patent Document 1, when performing spinal deformity correction and fixation surgery using a procedure that involves making a large incision in the patient's back or a percutaneous procedure (minimally invasive surgery), it is difficult for the surgical staff, including the surgeon, to obtain the degree of curvature of the rod, i.e., the detailed direction and angle of curvature, that will provide the optimal correction effect for the patient when curving the rod before placing it inside the patient's body.

[0010] The present invention has been made in consideration of the above points, and teaches the surgical staff, including the surgeon, the degree of curvature of the rod that will provide the optimal correction effect for the patient, before the rod is placed inside the body, without relying on the experience or intuition of the surgical staff, including the surgeon. Templates The object of the present invention is to provide a method for producing the above-mentioned compound. [Means for solving the problem]

[0011] For reference, the first aspect of the template is a template that is attached to each vertebra of the spine and is used when placing a rod configured as an implant material inside the patient's body, and is characterized in that, prior to placing the rod inside the body, it instructs the surgical staff, including the surgeon, on the degree of curvature of the entire rod that corresponds to the morphological angle of the pelvis specific to the patient. First aspect of this template In the MRI system, the template allows the surgeon and other surgical staff to learn the degree of curvature of the entire rod that corresponds to the patient's specific morphological angle before the rod is placed inside the body. As a result, the rod, which is curved according to the template, can be used to correct and fix the spinal deformity, achieving the optimal correction effect for the patient.

[0012] The pelvic morphological angle (PI) is an angle specific to each patient, and the anatomically normal sagittal alignment (arrangement of the vertebrae) of the spine is established based on this morphological angle. In other words, differences in the morphological angle result in different angles of kyphosis of the thoracic spine and lordosis of the lumbar spine, resulting in the thoracic and lumbar vertebrae being balanced in the sagittal plane according to the morphology of the pelvis.

[0013] and, First aspect of this template In this method, the template can be used to teach the optimal rod shape, i.e., the rod shape with the optimal curvature, that corresponds to the morphological angle of the pelvis specific to the patient, so that the spinal deformity can be corrected and fixed using the rod with the optimal curvature taught by the template without relying on the experience or intuition of the surgical staff, including the surgeon, thereby making it possible to approach normal spinal alignment, that is, to obtain the optimal correction effect for each patient. First aspect of this template In this method, the surgical staff, including the surgeon, uses a template to bend the rod to the optimal rod shape that corresponds to the morphological angle specific to each patient, thereby realizing semi-customized treatment for each patient.

[0014] In addition, the template must be prepared appropriately for different approaches to the patient (such as a procedure that involves making a large incision in the patient's back or a percutaneous procedure), different rod materials (such as titanium or cobalt-chromium alloy), and different rod outer diameters.

[0015] The second aspect of the template is the first aspect The template is characterized by having a display section that displays the rod shape showing the degree of curvature of the entire rod in two dimensions. Second aspect of this template With this, the surgical staff, including the surgeon, can easily bend the rod to conform to the rod shape shown on the display portion of the template.

[0016] A third aspect relating to the template is the second aspect, The template is characterized in that the display portion is provided on the surface of a plate material. Third aspect of this template In the present invention, a display unit is provided on the surface of the plate, i.e., the upper surface and / or the lower surface, and the plate can be easily brought into the operating room, thereby improving its handling.

[0017] A fourth aspect relating to the template is the second aspect, The display unit is characterized in that an inflection point of the rod shape is displayed. Fourth aspect of this templateIn this case, when the rod is curved using a template, the position of the inflection point (the inflection point that marks the boundary between lumbar lordosis and thoracic kyphosis) can be grasped as one of the indicators for sagittal plane correction by rod fixation for spinal deformity, allowing the surgeon to imagine the corrected position of the patient after surgery.

[0018] A fifth aspect relating to the template is the first aspect, The template is characterized in that it is made of a temporary rod that has been bent two-dimensionally or three-dimensionally to the same degree of curvature as the entire rod. Fifth aspect of this template This is particularly effective when the degree of curvature of the entire rod (rod shape) is three-dimensional.

[0019] Claim 1 The invention relating to the manufacturing method of the template is a manufacturing method of a template that is attached to each vertebra of the spine and that instructs the surgical staff, including the surgeon, on the degree of curvature when curving a rod configured as an implant material in the patient's body before the rod is placed inside the patient's body. a rod shape acquisition step of acquiring, based on a large number of past cases, data on rod shapes curved while placed in the body and rod shapes bent before being placed in the body; a morphology angle classification step of classifying the large number of rod shapes curved while placed in the body acquired in the rod shape acquisition step into groups for each patient-specific pelvic morphology angle; an approximate rod shape acquisition step of calculating an approximate curve for each pelvic morphology angle based on the large number of rod shapes classified into groups for each pelvic morphology angle in the morphology angle classification step, and acquiring a single rod shape having the curve; a rod deformation amount calculation step of comparing the rod shape curved while placed in the body of the same patient acquired in the rod shape acquisition step with the rod shape bent before being placed in the body, and calculating a rod deformation amount for each morphology angle; and a template manufacturing step of deriving a rod shape having an optimal curvature for each morphology angle by taking the deformation amount calculated for each morphology angle in the rod deformation amount calculation step into account for the rod shape for each morphology angle acquired in the approximate rod shape acquisition step, and manufacturing a template based on the rod shape. It is characterized by the following. Claim 1 In the invention, the optimal rod shape, i.e., the rod shape having the optimal curvature, can be derived for each morphological angle of the pelvis specific to the patient, and a template can be produced that teaches the degree of curvature of the entire rod corresponding to the morphological angle. 、 By correcting and fixing the spinal deformity with rods instructed by the template, it is possible to obtain optimal correction effects for each patient without relying on the experience or intuition of the surgical staff, including the surgeon.

[0021] Furthermore, depending on the degree of hardness or softness of each patient's spinal deformity for correction, or in the surgical environment, for example, in the surgical environment after placing an LIF cage between vertebral bodies, even if the morphological angle is approximately the same for each patient, the amount of deformation of the rod may differ significantly when comparing the curved rod shape when placed in the body with the rod shape bent before being placed in the body.

[0022] In view of these circumstances, The invention of claim 1In particular, the method includes a rod deformation amount calculation process in which the rod shape curved when placed inside the body, acquired in the rod shape acquisition process, is compared with the rod shape bent before being placed inside the body, and the deformation amount is calculated for each morphological angle; and a template manufacturing process in which the deformation amount calculated for each morphological angle in the rod deformation amount calculation process is added to the rod shape for each morphological angle acquired in the approximate rod shape acquisition process to derive an optimal rod shape for each morphological angle, and a template is manufactured based on the rod shape, thereby improving the accuracy of obtaining a rod shape with an optimal curvature for each patient.

[0023] Claim 2 The invention relating to the manufacturing method of the template is as follows: 1 In the invention described above, between the morphological angle classification step and the approximate rod shape acquisition step, a rod length classification step is provided in which, based on the numerous rod shapes classified into groups for each pelvic morphological angle, the rods are classified into groups for each of a plurality of set total lengths at each morphological angle, and the approximate rod shape acquisition step calculates an approximate curve based on the numerous rod shapes classified into groups for each rod total length at each morphological angle acquired in the morphological angle classification step and the rod length classification step, and a single rod shape having the curve is acquired. Claim 2 In the invention, in the rod length classification step, the rod shapes are obtained by classifying into groups according to rod length at each morphological angle, so that the accuracy can be further improved to obtain the optimal rod shape for each patient.

[0024] Claim 3 The invention relating to the manufacturing method of the template is as follows: 1 In the invention described above, the deformation amount includes a difference in the lumbar lordosis angle. Claim 3 In the invention, the amount of deformation can be calculated with high accuracy by calculating at least the difference in the lumbar lordosis angle (LL) on the lumbar side from the inflection point of the rod.

[0025] Claim 4The invention relating to the manufacturing method of the template is as follows: 1 In the invention described above, in the template manufacturing process, when the configuration angle is in the range of 40° to 49°, multiple rod shapes having optimal curvatures are set, and also when the configuration angle is in the range of 50° to 59°, multiple rod shapes having optimal curvatures are set. Claim 4 In this invention, it is possible to select a rod shape with the optimal curvature taking into consideration the degree of hardness or softness for the correction of each patient's spinal deformity, as well as the special surgical environment, such as the surgical environment after placing an LIF cage between adjacent vertebrae. From this point of view, it is possible to improve the accuracy in obtaining the optimal rod shape for each patient. [Effects of the Invention]

[0026] It is a reference The template allows the surgical staff, including the surgeon, to learn the degree of rod curvature that will provide the optimal correction effect for the patient before the rod is placed inside the body, without relying on the experience or intuition of the surgical staff, including the surgeon. Furthermore, the template manufacturing method according to the present invention allows for the determination of rod shapes having the optimal curvature for each morphological angle of the patient's pelvis based on a large number of past cases, and for the manufacturing of templates based on these rod shapes. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a schematic diagram illustrating a percutaneous spinal stabilization system. [Figure 2] FIG. 2 is a plan view of a display section on the top surface of a plate material used in the template according to this embodiment, on which the shapes of the rods are displayed. [Figure 3] FIG. 3 is a plan view of a display section on the underside of the plate material used in the template according to this embodiment, on which the shapes of the rods are displayed. [Figure 4] FIG. 4 is a perspective view of a temporary rod which is a template according to another embodiment. [Figure 5]FIG. 5 is a diagram showing the balance of the spine on the sagittal plane. [Figure 6] FIG. 6 is an enlarged view of part A in FIG. [Figure 7] FIG. 7 is a flow diagram showing a method for manufacturing a template according to an embodiment of the present invention. [Figure 8] Figure 8(a) shows a number of rod shapes that were classified into a morphological angle range of 30° to 39° in the morphological angle classification process from a large number of data on rod shapes bent while placed inside the body, and were also classified by total rod length in the rod length classification process, and (b) shows a single rod shape (central axis line) having an approximate curve (average curve) calculated from the large number of classified rod shapes. [Figure 9] FIG. 9 is a diagram showing angle parameters from the thoracic vertebra T10 to the sacrum S of the spinal column. [Figure 10] FIG. 10 is a diagram showing the shape of a rod having a morphological angle (PI) of 40° to 49° and a total length of 305 mm, acquired through the rod shape acquisition step, morphological angle classification step, rod length classification step, and approximate rod shape acquisition step. [Figure 11] Figure 11 shows the T10-L1 kyphosis angle, lumbar lordosis angle (LL), and lower lumbar lordosis angle (LLL) for each morphological angle (PI) obtained through the rod shape acquisition process, morphological angle classification process, rod length classification process, and approximate rod shape acquisition process. [Figure 12] Figure 12 shows the lumbar lordosis angle of the rod shape (patient) after placement in the body obtained in the rod shape acquisition process, the patient's corrected target lumbar lordosis angle, the deformation amount obtained in the rod deformation amount calculation process, and the final rod shape lumbar lordosis angle obtained in the template manufacturing process in patterns 1 to 6. [Figure 13] FIG. 13 shows the central axes of the rod shapes finally calculated and derived in patterns 1 to 6. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. As shown in Figure 1, a percutaneous spinal stabilization system 1, which corrects and stabilizes spinal deformities by percutaneously approaching a patient from behind, is used in various surgical treatments for adult spinal deformities, such as degenerative kyphoscoliosis, lumbar spondylolisthesis, and dislocated spinal tumors. The percutaneous spinal stabilization system 1 includes multiple pedicle screws 2 that are screwed into the vertebral bodies via the pedicles of each vertebra in the spine, and rods 3 that are arranged along the craniocaudal direction of the spine and connected to the heads 2A of each pedicle screw 2, thereby correcting, fixing, and stabilizing spinal deformities. In this embodiment, the pedicle screws 2 and rods 3 are made of titanium.

[0029] The percutaneous spinal stabilization system 1 shown in FIG. 1 corrects and fixes spinal deformities by percutaneously inserting pedicle screws 2 and rods 3 into the patient's body (through several small incisions) from the back and fixing them to each vertebra. The percutaneous spinal stabilization system 1 shown in FIG. 1 includes an LIF cage 4 interposed between adjacent lumbar vertebrae. The LIF cage 4 is a cage used in lateral lumbar interbody fusion (LLIF). In FIG. 1, the LIF cage 4 is interposed at three locations. The rods 3 of the percutaneous spinal stabilization system 1 are bent before being placed percutaneously in the body to achieve optimal correction for the patient. This bending is performed by staff, including the surgeon, based on the shape of each rod shown on the display section 12 of the template 10 (described later). A dedicated surgical instrument, such as a plate bender, is used to appropriately bend the rods 3. In this embodiment, the pedicle screws 2, rods 3, and LIF cage 4 correspond to implants.

[0030] Next, a template 10 according to an embodiment of the present invention will be described with reference to FIGS. 2 and 3. The template 10 according to this embodiment is intended to instruct the surgical staff, including the surgeon, on the degree of curvature of the entire rod 3 before the rod 3 is placed inside the patient's body. Specifically, the template 10 according to this embodiment is intended to instruct the surgical staff, including the surgeon, on the degree of curvature of the entire rod 3 corresponding to the patient-specific pelvic morphological angle (PI) (described in detail later) before the rod 3 is placed inside the patient's body. The template 10 according to this embodiment is provided with display units 12 on the surfaces of a thin plate 11, i.e., on the upper surface (see FIG. 2) and lower surface (see FIG. 3) of the plate 11, which display rod shapes for each morphological angle (PI) (for each of patterns 1 to 6 shown in FIG. 12, which will be described in detail later) that can achieve the optimal correction effect for the patient. The rod shapes for each morphological angle (PI) (for each of patterns 1 to 6 shown in FIG. 12) represent the overall curvature of the rod 3 in two dimensions. The plate 11 is made of metal, synthetic resin, or the like. The plate material 11 is not limited to these materials as long as it is compatible with sterilization.

[0031] Specifically, the display unit 12 (upper and lower surfaces of the plate material 11) of the template 10 displays rod shapes for each configuration angle (PI), which will be described in detail later, i.e., for patterns 1 to 6 (45°, 50°, 55°, 60°, 65°, and 70°, which correspond to the lumbar lordosis angle (LL) in the final rod shape shown in FIG. 12 ), with the rods 3 having the same overall length (285 mm in FIGS. 2 and 3 ) and outer diameter (5.5 mm in FIGS. 2 and 3 ). These rod shapes for patterns 1 to 6 are displayed based on the finally calculated rod axis shown in FIG. 13 . On the upper surface, which is the display unit 12 of the template 10, rod shapes for a configuration angle (PI) in the range of 30° to 39° (Pattern 1), a configuration angle (PI) in the range of 40° to 49° (Pattern 2), and a configuration angle (PI) in the range of 50° to 59° (Pattern 3) are displayed, from top to bottom, as shown in FIG. 2 . On the other hand, on the bottom surface of the template 10, which is the display unit 12, as shown in FIG. 3, from top to bottom, rod shapes with a configuration angle (PI) in the range of 40° to 49° (pattern 4), rod shapes with a configuration angle (PI) in the range of 50° to 59° (pattern 5), and rod shapes with a configuration angle (PI) in the range of 60° or more (pattern 6) are displayed.

[0032] Furthermore, each rod shape displayed on the display unit 12 shows the positions of the thoracic vertebra (T10) to the sacrum (S2) of the spine when the rod 3 is placed inside the body, three 1 / 4 reference lines for the entire length of the rod 3, the position of the apex, and the position of the inflection point (IP). The display unit 12 also displays the entire length and the outer diameter of the rod 3. It is known that the inflection point (IP) of the rod shape, i.e., the inflection point (IP) which is the boundary between lumbar lordosis and thoracic kyphosis, is located closer to the cranial side as the morphological angle (PI) of the patient increases, and similarly, the position of the apex vertebra of the lumbar lordosis is located closer to the cranial side as the morphological angle (PI) increases.

[0033] Understanding the location of the inflection point and apical vertebra as indicators for sagittal plane correction using rod fixation also helps the surgeon visualize the patient's corrected position after surgery. Furthermore, it is known that an inflection point located too close to the cephalad side (more cephalad than the thoracic vertebra T12) is associated with postoperative collapse of the non-fixed vertebrae above the fused vertebra and loss of correction (technically referred to as PJK / PJF (proximal junctional kyphosis / failure)). Therefore, understanding the location of the inflection point and apical vertebra is an important factor in determining the appropriate corrective fixation position. Furthermore, the position of the three 1 / 4 reference lines relative to the entire length of the rod 3 is the position at which the rod 3 is supported by a dedicated surgical instrument, such as a plate bender, when bending the rod 3 according to its shape. The aforementioned template 10 is available in four lengths for the rod 3: 285 mm, 295 mm, 305 mm, and 320 mm, as described below. Therefore, a total of four templates are prepared, one for each length of the rod 3.

[0034] In the template 10 according to this embodiment, the rod shapes for patterns 1 to 6 are displayed on the display units 12 on the upper and lower surfaces of the plate 11. Alternatively, the rod shapes for patterns 1 to 6 may be displayed on either one surface (the upper surface) of the plate 11. In the template 10 according to this embodiment, the rod shapes are displayed as lines on the upper and lower surfaces of the plate 11. Alternatively, recesses having a width substantially equal to the rod diameter may be formed along the rod shapes. In this embodiment, after the rod 3 is bent, the rod 3 can be fitted into the recess of the taught rod shape to confirm the bending. As shown in FIG. 4, a template 10A according to another embodiment may be formed using a temporary rod 15 that has been bent in advance in three dimensions to determine the degree of curvature of the entire rod 3.

[0035] Next, a method for manufacturing the template 10 according to an embodiment of the present invention will be described. Regarding the method for manufacturing the template 10, a method for deriving a rod shape for each configuration angle (PI) displayed on the display unit 12 of the template 10 shown in FIGS. 2 and 3, i.e., for each of patterns 1 to 6, which will be described in detail later, will be described in detail. In the method for deriving a rod shape for each of patterns 1 to 6 described below, a titanium rod 3 with an outer diameter of 5.5 mm is used in this embodiment. Based on numerous past cases, a rod shape having an optimal curvature is derived and displayed on the display unit 12 of the template 10 for each patient-specific pelvic configuration angle (PI). As described above, the pelvic configuration angle (PI) shown in FIGS. 5 and 6 is an angle specific to each patient, and an anatomically normal sagittal alignment (vertebral arrangement) of the spine is established based on the configuration angle (PI). In other words, differences in the morphological angle (PI) result in different thoracic kyphosis angles (TK) and lumbar lordosis angles (LL), resulting in the thoracic and lumbar vertebrae being balanced in the sagittal plane depending on the pelvic morphology.

[0036] More specifically, the method for manufacturing the template 10 according to this embodiment involves performing the following steps in this order, as shown in Fig. 7: rod shape acquisition step S1 → morphology angle classification step S2 → rod length classification step S3 → approximate rod shape acquisition step S4 → rod deformation amount calculation step S5 → template manufacturing step S6. First, in the rod shape acquisition step S1, data on the shape of the rod curved when placed in the body and the shape of the rod bent before being placed in the body are acquired based on many past cases.

[0037] In the rod shape acquisition step S1, first, data on the shape of the rod bent before being placed inside the body is acquired. Specifically, an image of the rod 3 bent before being placed is loaded into CAD (Computer Aided Design). Next, multiple plots are manually made at predetermined intervals along the central axis of the rod 3 loaded into the CAD. Next, the coordinates of each of the multiple plots are measured, and an approximation curve (cubic equation) is calculated based on each of the coordinates. Next, a rod shape (two-dimensional) is calculated with the approximation curve as the central axis. Next, the coordinates of the inflection points are calculated for each of the many bent rod shapes accumulated as data.

[0038] Next, in the rod shape acquisition step S1, data on the curved rod shape when placed inside the body is acquired. Specifically, an X-ray image of the pedicle screw 2 including the rod 3 attached to the patient's spine is loaded into CAD. Next, multiple central positions of the connection portion between the rod 3 and the head 2A of the pedicle screw 2, specifically the overlapping portion of the rod 3 and the head 2A of the pedicle screw 2, are manually plotted (the same number as the pedicle screw 2). Next, the coordinates of each of the multiple plots are measured, and an approximate curve (cubic equation) is calculated based on the coordinates. Next, a rod shape (two-dimensional) is calculated with the approximate curve as the central axis. Next, the coordinates of the inflection points are calculated for each of the many rod shapes after placement inside the body that have been accumulated as data.

[0039] Next, a morphological angle classification step S2 is performed. In the morphological angle classification step S2, the rod shapes curved while placed in the body, acquired in the rod shape acquisition step S1, are classified into groups according to the pelvic morphological angle (PI) specific to the patient. The pelvic morphological angle (PI) is set to four types, for example, a range of 30° to 39°, a range of 40° to 49°, a range of 50° to 59°, and a range of 60° or more. Next, a rod length classification step S3 is performed. In the rod length classification step S3, the morphological angles (PI) (the four types mentioned above) are classified into groups according to the set total lengths of the rods 3. The total lengths of the rods 3 are set to four types, for example, 285 mm, 295 mm, 305 mm, and 320 mm. In this embodiment, the total lengths of the rods 3 are set to four types, 285 mm, 295 mm, 305 mm, and 320 mm, but are not limited to these four types.

[0040] The method of classification by rod length will be described in detail. That is, the rod shape obtained from the X-ray image is obtained by plotting multiple connection points between the rod 3 and the head 2A of each pedicle screw 2, and the rod shape is calculated appropriately so that the total length of the rod shape matches the set total length of each rod 3. For example, if the total length of the rod shape obtained from the X-ray image is approximately 275 mm, the rod shape is appropriately enlarged using a similarity ratio so that the total lengths become 285 mm, 295 mm, 305 mm, and 320 mm, respectively, to calculate rod shapes with total lengths of 285 mm, 295 mm, 305 mm, and 320 mm, respectively. Also, if the total length of the rod shape obtained from the X-ray image is approximately 300 mm, the rod shape is appropriately enlarged using a similarity ratio so that the total lengths become 285 mm, 295 mm, 305 mm, and 320 mm, respectively, to calculate rod shapes with total lengths of 285 mm, 295 mm, 305 mm, and 320 mm, respectively. In this way, all rod shapes obtained from X-ray images were appropriately enlarged or reduced using a similarity ratio to have four different total lengths: 285 mm, 295 mm, 305 mm, and 320 mm. All rod shapes obtained from X-ray images were then classified into four different total lengths.

[0041] The shapes of the many curved rods placed inside the body, acquired in the rod shape acquisition step S1, are classified into a total of 16 types, including four types for each morphological angle (PI) and four types for the total length of the rod 3. Note that Fig. 8(a) illustrates many rod shapes (central axes) acquired from X-ray images, classified into four total lengths of the rod 3 (285 mm, 295 mm, 305 mm, 320 mm) within the range of morphological angle (PI) 30° to 39°.

[0042] Next, an approximate rod shape acquisition step S4 is performed. In the approximate rod shape acquisition step S4, an approximate curve (average curve) of the rod shape is calculated for each of the 16 types based on the numerous rod shapes (central axes) classified into 16 types acquired in the rod shape acquisition step S1, the morphological angle classification step S2, and the rod length classification step S3, and a single rod shape having this curve is acquired for each of the 16 types. In FIG. 8(b), a single rod shape (central axis) is illustrated based on numerous rod shapes (central axes) classified into four total lengths of the rod 3 (285 mm, 295 mm, 305 mm, 320 mm) in the morphological angle (PI) range of 30° to 39°. In short, a single rod shape is derived for each of the 16 types through the rod shape acquisition step S1, the morphological angle classification step S2, the rod length classification step S3, and the approximate rod shape acquisition step S4.

[0043] FIG. 10 shows rod shapes, for example, with a morphological angle (PI) of 40° to 49° and a total length of 305 mm, acquired through the rod shape acquisition step S1, morphological angle classification step S2, rod length classification step S3, and approximate rod shape acquisition step S4. The coordinates (positions) of the inflection points are calculated for each of the 16 types of rod shapes. Furthermore, for each of the 16 types of rod shapes, the T10-L1 kyphosis angle, lumbar lordosis angle (LL), and lower lumbar lordosis angle (LLL) are calculated using a specific calculation method based on X-ray images. FIG. 11 shows the T10-L1 kyphosis angle, lumbar lordosis angle (LL), lower lumbar lordosis angle (LLL), and inflection point positions for the rod shapes for each morphological angle (PI) acquired through the rod shape acquisition step S1, morphological angle classification step S2, rod length classification step S3, and approximate rod shape acquisition step S4. In the approximate rod shape acquisition process S4, a total of 16 types of rod shapes are calculated for each morphological angle (PI) and each rod length, but the T10-L1 kyphosis angle, lumbar lordosis angle (LL), lower lumbar lordosis angle (LLL), and inflection point position for each morphological angle (PI) are constant regardless of the rod length (4 types).

[0044] Next, a rod deformation amount calculation step S5 is performed. In the rod deformation amount calculation step S5, the rod shape curved when placed in the body of the same patient, acquired in the rod shape acquisition step S1, is compared with the rod shape bent before being placed in the body, and the deformation amount of the rod 3 is calculated for each morphological angle (PI). Specifically, the rod shape curved when placed in the body in the X-ray image of the same patient, acquired in the rod shape acquisition step S1, and the rod shape bent before being placed in the body (drawn in the diagram) are superimposed on the CAD so that their inflection points match. Next, on the CAD, the difference in the lumbar lordosis angle (LL) (see FIG. 9) is calculated as the deformation amount between the rod shape curved when placed in the body in the X-ray image and the rod shape bent before being placed in the body. This deformation amount is shown in FIG. 12. This deformation amount varies between 5° and 15° as the difference in lumbar lordosis angle (LL) for each morphological angle (PI), that is, for patterns 1 to 6 in FIG.

[0045] Next, a template manufacturing process S6 is performed. In the template manufacturing process S6, the deformation amount (difference in lumbar lordosis angle (LL)) calculated for each configuration angle (PI) in the rod deformation amount calculation process S5 is added to the single rod shape calculated for each configuration angle (PI) (and for each rod length) acquired in the approximate rod shape acquisition process S4 to derive a rod shape for each configuration angle (PI) (and for each rod length), and a template 10 is manufactured based on the rod shape. In detail, referring to FIG. 12, in pattern 1 (configuration angle (PI): 30° to 39°), the deformation amount is 10°, so the lumbar lordosis angle (LL) after target patient correction of 35° is added to the deformation amount of 10°, and the lumbar lordosis angle (LL) of the final rod shape is set to 45°. Then, for all rod shapes of total lengths of 285 mm, 295 mm, 305 mm, and 320 mm in the morphological angle (PI) range of 30° to 39° acquired in the approximate rod shape acquisition step S4, the lumbar lordosis angle (LL) is set to 45°. In pattern 1 (morphological angle (PI): 30° to 39°), the inflection point of the final rod shape is at the position of the second lumbar vertebra (L2).

[0046] In addition, in pattern 2 (configuration angle (PI): 40° to 49°), the deformation amount is 5°, so the deformation amount of 5° is added to the lumbar lordosis angle (LL) of 45° after target patient correction, and the lumbar lordosis angle (LL) of the final rod shape is set to 50°. Then, for all rod shapes with total lengths of 285 mm, 295 mm, 305 mm, and 320 mm in the configuration angle (PI): range of 40° to 49° acquired in the approximate rod shape acquisition step S4, the lumbar lordosis angle (LL) is set to 50°. Furthermore, in pattern 4 (configuration angle (PI): 40° to 49°), the deformation amount is 15°, so the deformation amount of 15° is added to the lumbar lordosis angle (LL) of 45° after target patient correction, and the lumbar lordosis angle (LL) of the final rod shape is set to 60°. Then, for all rod shapes of total lengths of 285 mm, 295 mm, 305 mm, and 320 mm in the morphological angle (PI) range of 40° to 49° acquired in the approximate rod shape acquisition step S4, the lumbar lordosis angle (LL) is set to 60°. In patterns 2 and 4 (morphological angle (PI): 40° to 49°), the inflection point of the final rod shape is at the position of the first lumbar vertebra (L1).

[0047] In Patterns 2 and 4, the amount of deformation differs between 5° and 15° at the same configuration angle (PI): 40° to 49°, so the lumbar lordosis angle (LL°) of the final rod shape is set to 50° or 60°, but this is set appropriately taking into consideration the degree of hardness or softness in correcting each patient's spinal deformity and the circumstances of the surgical environment, for example, the surgical environment after placing the LIF cage 4 between the vertebral bodies. Therefore, in Patterns 2 and 4, which have a configuration angle (PI): range of 40° to 49°, if it is determined that the range is too hard (difficult to correct) for correcting the patient's spinal deformity, the final rod shape of Pattern 4 is adopted.

[0048] Furthermore, in pattern 3 (configuration angle (PI): 50° to 59°), the deformation amount is 5°, so the deformation amount of 5° is added to the lumbar lordosis angle (LL) of 50° after target patient correction, and the lumbar lordosis angle (LL) of the final rod shape is set to 55°. Then, for all rod shapes with total lengths of 285 mm, 295 mm, 305 mm, and 320 mm in the configuration angle (PI): range of 50° to 59° acquired in the approximate rod shape acquisition step S4, the lumbar lordosis angle (LL) is set to 55°. Furthermore, in pattern 5 (configuration angle (PI): 50° to 59°), the deformation amount is 10° (or 15°), so the deformation amount of 10° (or 15°) is added to the lumbar lordosis angle (LL) of 55° (or 50°) after target patient correction, and the lumbar lordosis angle (LL) of the final rod shape is set to 65°. Then, for all rod shapes of total length 285 mm, 295 mm, 305 mm, and 320 mm in the morphological angle (PI): range of 50° to 59° acquired in the approximate rod shape acquisition step S4, the lumbar lordosis angle (LL) is set to 65°. In patterns 3 and 5 (morphological angle (PI): 50° to 59°), the inflection point of the final rod shape is at the position of the first lumbar vertebra (L1).

[0049] In Patterns 3 and 5, the amount of deformation differs between 5° and 10° (15°) at the same configuration angle (PI): 50° to 59°, so the lumbar lordosis angle (LL) of the final rod shape is set to 55° or 65°, but this is set appropriately taking into consideration the degree of hardness or softness in correcting each patient's spinal deformity and the circumstances of the surgical environment, for example, the surgical environment after placing the LIF cage 4 between the vertebral bodies. Therefore, in Patterns 3 and 5, which have a configuration angle (PI): range of 50° to 59°, if it is determined that the patient's spinal deformity is too hard (difficult to correct), for example, the final rod shape of Pattern 5 is adopted.

[0050] Furthermore, in pattern 6 (configuration angle (PI): 60° or more), the deformation amount is 10°, so the deformation amount of 10° is added to the lumbar lordosis angle (LL) of 60° after the target patient correction, and the lumbar lordosis angle (LL) of the final rod shape is set to 70°. Then, for all rod shapes with total lengths of 285 mm, 295 mm, 305 mm, and 320 mm at a configuration angle (PI): 60° or more acquired in the approximate rod shape acquisition step S4, the lumbar lordosis angle (LL) is set to 70°. In pattern 6 (configuration angle (PI): 60° or more), the inflection point of the final rod shape is the position of the first lumbar vertebra (L1). FIG. 13 shows the rod shapes (central axes) finally calculated and derived for all rod shapes with total lengths of 285 mm, 295 mm, 305 mm, and 320 mm in patterns 1 to 6. In this embodiment, in patterns 1 to 6, the lumbar lordosis angle (LL) of all 16 types of rod shapes (actually 4 types due to differences in morphological angle (PI)) calculated in the approximate rod shape acquisition process S4, i.e., the values ​​in the column for lumbar lordosis angle LL (°) of rod shape (patient) after placement in the body in Figure 12 (values ​​of patterns 1 to 6) are reference values ​​and are not directly taken into consideration when calculating the final rod shape.

[0051] Subsequently, in the template manufacturing process S6, the template 10 is manufactured based on each rod shape that has been finally calculated and derived as described above. That is, in the template manufacturing process S6, the rod shape along the central axis that has been finally calculated and derived for each of patterns 1 to 6 shown in Fig. 13 is displayed on the display unit 12 on the surface of the plate material 11, i.e., the upper and lower surfaces, to manufacture the template 10. The detailed display form has been described above, so a description thereof will be omitted here.

[0052] In this embodiment, in the rod deformation amount calculation step S5, the deformation amount of the rod 3 obtained by comparing the shape of the rod curved in the X-ray image while it is placed inside the body with the shape of the rod bent before being placed inside the body on CAD is calculated as the difference in the lumbar lordosis angle (LL), but in order to improve the accuracy of the deformation amount, the deformation amount may be calculated taking into consideration the difference in the lumbar lordosis angle (LL) and the difference in the T10-L1 kyphosis angle on the thoracic side from the inflection point of the rod 3. Furthermore, in this embodiment, the difference in the lumbar lordosis angle (LL) and the difference in the T10-L1 kyphosis angle are used as evaluation indices for the deformation amount, but other evaluation indices may also be used.

[0053] Furthermore, the manufacturing method of the template 10 according to this embodiment includes the rod length classification step S3, which is the best mode from the viewpoint of handling (sales strategy, etc.), but the rod length classification step S3 is not necessarily included in the process of setting the final rod shape. That is, the T10-L1 kyphosis angle, lumbar lordosis angle (LL), and lower lumbar lordosis angle (LLL) for each morphological angle (PI) calculated in the approximate rod shape acquisition step S4 are constant regardless of the rod length (four types). Furthermore, when setting the final rod shape in the template manufacturing step S6, the lumbar lordosis angle (LL) is different for each of patterns 1 to 6 (different morphological angles (PI)), and rod length is not involved. Therefore, the rod length classification step S3 is not necessarily included. In short, the final rod shapes in FIGS. 12 and 13 may be appropriately scaled by a similarity ratio according to the set rod length to derive a rod shape for each set rod length.

[0054] The template 10 according to the present embodiment described above can teach the surgical staff, including the surgeon, the degree of curvature of the entire rod corresponding to the patient's specific pelvic morphological angle (PI), before placing the rod 3 inside the body. This makes it possible to correct and fix spinal deformity using the rod 3 having the optimal curvature taught by the template 10 according to the present embodiment, without relying on the experience or intuition of the surgical staff, including the surgeon, thereby achieving the optimal correction effect for each patient.

[0055] Furthermore, the template 10 according to this embodiment includes a display unit 12 that displays the rod shape, which shows the degree of curvature of the entire rod in two dimensions. This allows the surgeon and other surgical staff to easily bend the rod 3 so that it follows the rod shape shown on the display unit 12 of the template 10.

[0056] Furthermore, the template 10 according to this embodiment has a display unit 12 provided on the surface of the plate 11, i.e., on the upper and / or lower surface. This allows the plate 11 to be easily brought into an operating room, making it easier to handle. If the plate 11 is made of sterilizable synthetic resin, it can be made lighter, making it easier to handle.

[0057] Furthermore, the display unit 12 of the template 10 according to this embodiment displays inflection points for the rod shape, which shows the degree of curvature of the entire rod in two dimensions. This allows the position of the inflection point to be grasped as one of the indicators for sagittal plane correction by rod fixation for spinal deformity in the rod 3 curved using the template 10 according to this embodiment, and allows the correction position of the patient after surgery to be visualized.

[0058] Furthermore, the template 10 according to this embodiment is ideal for teaching surgical staff, including surgeons, the degree of curvature of the rod 3 employed in the percutaneous spinal stabilization system 1. In other words, the load on the rod 3 differs between percutaneous surgical procedures (minimally invasive surgery) and those involving a large back incision, resulting in a different amount of deformation of the rod 3. Therefore, it is not possible to teach the curvature of the rod 3 that corresponds to a procedure involving a large back incision. However, even in a procedure involving a large back incision, the manufacturing method for the template 10 according to this embodiment can be adopted, and the final rod shape can be derived from analysis results corresponding to those shown in FIG. 12 to manufacture the template 10. This template 10 is intended solely to teach the curvature of the rod 3 that corresponds to a procedure involving a back incision, and is not intended to teach the curvature of the rod 3 that corresponds to a percutaneous surgical procedure.

[0059] Furthermore, the template 10A according to another embodiment is configured with a temporary rod 15 that has been bent three-dimensionally to change the degree of curvature of the entire rod. This is particularly effective when the degree of curvature of the entire rod (rod shape) is three-dimensional.

[0060] On the other hand, according to the manufacturing method of the template 10 according to the present embodiment described above, a rod shape having an optimal curvature is derived for each patient-specific pelvic morphological angle (PI) based on a large number of past cases, and the template 10 is manufactured based on the rod shape. As a result, even if the surgeon has little experience in percutaneous surgical procedures, the rod 3 having the optimal curvature taught by the template 10 can be used to correct and fix the spinal deformity, thereby achieving the optimal correction effect for each patient, without relying on the experience or intuition of the surgical staff, including the surgeon.

[0061] Furthermore, the manufacturing method of the template 10 according to this embodiment is particularly provided with a rod deformation amount calculation step S5, and the calculation results in the rod deformation amount calculation step S5 are reflected in the final rod shape in the template manufacturing step S6. Therefore, it is possible to obtain an optimal rod shape for each patient (even if the morphological angle (PI) is the same) depending on the degree of hardness or softness in correcting the spinal deformity of each patient and in the surgical environment, for example, in the surgical environment after the LIF cage 4 is installed between the vertebral bodies.

[0062] Furthermore, the manufacturing method of the template 10 according to this embodiment includes a rod length classification process S3, in which the rod shapes are obtained by classifying the rods into groups according to rod length at each morphological angle (PI), thereby further improving the accuracy in obtaining the optimal rod shape for each patient.

[0063] Furthermore, in the manufacturing method of the template 10 according to this embodiment, in the template manufacturing step S6, when the patient-specific configuration angle (PI) is in the range of 40° to 49°, two types of rod shapes having optimal curvatures are set, and also when the configuration angle (PI) is in the range of 50° to 59°, two types of rod shapes having optimal curvatures are set. As a result, even if the patient-specific configuration angle (PI) is the same, it is possible to select the optimal rod shape for each patient based on the degree of flexibility in correcting the spinal deformity of each patient and the special surgical environment, for example, the surgical environment after placing the LIF cage 4 between vertebral bodies. This also makes it possible to improve the accuracy in obtaining the optimal rod shape for each patient.

[0064] The template 10 according to the present embodiment described above is applicable to percutaneous surgical procedures in which the rod 3 is made of titanium and has an outer diameter of 5.5 mm, but the template 10 must be prepared appropriately according to the approach to the patient to which it is applied, and the material and outer diameter of the rod 3 to be applied.

[0065] Furthermore, the template 10 of this embodiment described above is intended to instruct the surgical staff, including the surgeon, on the degree of curvature of the entire rod corresponding to the patient's specific pelvic morphological angle (PI) prior to placing the rod 3 of the percutaneous spinal stabilization system 1 inside the body. However, the template 10 of this embodiment may also be used as an educational tool for doctors and surgical staff who have little experience in percutaneous spinal deformity correction and fixation surgery, particularly for educating them on the degree of curvature of the rod 3 before surgery, for example, in surgical treatment of adult spinal deformity, etc., in which the percutaneous spinal stabilization system 1 is used. [Explanation of symbols]

[0066] 3 Rod, 10, 10A Template, 11 Plate, 12 Display, 15 Temporary Rod

Claims

1. A method for manufacturing a template that instructs surgical staff, including the surgeon, on the degree of curvature when a rod that is attached to each vertebra of the spine and configured as an implant material is to be curved before being placed inside the patient's body, comprising: a rod shape acquisition step for acquiring data on the shape of the rod bent when placed in the body and the shape of the rod bent before being placed in the body, based on many past cases; a morphological angle classification step of classifying the shapes of the rods curved when placed in the body, which are acquired in the rod shape acquisition step, into groups according to the morphological angles of the pelvis specific to the patient; an approximate rod shape acquisition step of calculating an approximate curve for each pelvic morphological angle based on the multiple rod shapes classified into groups for each pelvic morphological angle in the morphological angle classification step, and acquiring a single rod shape having the curve; a rod deformation amount calculation step of comparing the rod shape curved when placed in the body of the same patient, acquired in the rod shape acquisition step, with the rod shape bent before being placed in the body, and calculating the deformation amount of the rod for each morphological angle; a template manufacturing step of adding the deformation amount calculated for each configuration angle in the rod deformation amount calculation step to the rod shape for each configuration angle acquired in the approximate rod shape acquisition step to derive a rod shape having an optimal curvature for each configuration angle, and manufacturing a template based on the rod shape; A method for manufacturing a template, comprising:

2. Between the morphological angle classification step and the approximate rod shape acquisition step, a rod length classification step is provided for classifying the rods into a plurality of groups for each set total length at each morphological angle based on the many rod shapes classified into groups for each pelvis morphological angle, 2. The method for manufacturing a template according to claim 1, characterized in that in the approximate rod shape acquisition process, an approximate curve is calculated based on a large number of rod shapes classified into groups based on the total length of the rod at each morphological angle acquired in the morphological angle classification process and the rod length classification process, and a single rod shape having the curve is acquired.

3. The method for manufacturing a template according to claim 1 , wherein the deformation amount includes a difference in a lumbar lordosis angle.

4. In the template manufacturing process, In the range of the configuration angle of 40° to 49°, a plurality of rod shapes having optimal curvatures are set, The template manufacturing method according to claim 1, further comprising the step of setting a plurality of rod shapes having optimum curvatures even when the configuration angle is in the range of 50° to 59°.

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