Cross type biodegradable sternum fixing device

Abstract

The utility model discloses a crossed biodegradable sternum fixing device which comprises a fixing block, a first binding belt and a second binding belt. The first binding belt and the second binding belt are combined and fixed to the two adjacent side edges of the fixing block respectively. The first binding belt and the second binding belt have the same structure, one side surface comprises a plurality of tooth blocks, and the other side is a smooth surface; the fixing block comprises a first channel, a second channel and a latch structure located between the first channel and the second channel, the first channel extends in the first direction, and the second channel extends in the second direction; the latch structure comprises a partition plate, first latches formed by protruding the partition plate towards the interior of the first channel, and second latches formed by protruding the partition plate towards the interior of the second channel. The first binding belt is arranged in the first channel in a penetrating mode after winding the sternum, the second binding belt is arranged in the second channel in a penetrating mode after winding the sternum, an X-shaped binding structure is formed, the sternum is fixed in multiple directions, and the mechanical strength needed by transverse and longitudinal fixation of the sternum can be guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of cardiovascular surgical medical devices. More specifically, it relates to a cross-type biodegradable sternal fixation device. Background Technology

[0002] Cardiac surgery is an important field in the treatment of cardiovascular diseases, and its surgical procedures include congenital heart disease, coronary artery bypass grafting, and heart valve replacement. Cardiac surgery requires splitting the patient's sternum in the middle to expose the heart for surgical manipulation. After the surgery, stainless steel wire is used to wrap around the two split sternal bones to re-fix them.

[0003] When stainless steel wire is used to fix the sternum, it often causes poor wound healing because the wire comes into contact with the patient's subcutaneous tissue. Furthermore, as a foreign body, the stainless steel wire requires a second surgery to remove after the sternum has healed. The formation of scar tissue during bone healing after the initial surgery further complicates the removal of the wire. Current technology proposes using biodegradable sternal fixation straps to replace stainless steel wires for sternal fixation. However, biodegradable materials have low mechanical strength, and this strength further decreases as the strap degrades, failing to meet the requirements for sternal fixation. Utility Model Content

[0004] In view of the above problems, the purpose of this utility model is to provide a cross-type biodegradable sternal fixation device that is biodegradable and can meet the mechanical strength requirements of sternal fixation.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A cross-type biodegradable sternal fixation device, comprising:

[0007] A fixing block and a first and second straps respectively attached to two adjacent sides of the fixing block;

[0008] The first and second straps have the same structure, with one side surface having multiple evenly distributed toothed blocks and the other side surface being a smooth surface;

[0009] The fixing block includes a first channel, a second channel, and a toothed structure located between the first channel and the second channel, wherein the first channel extends along a first direction and the second channel extends along a second direction;

[0010] The tooth structure includes a partition plate, a first tooth protruding from the partition plate into the first channel, and a second tooth protruding from the partition plate into the second channel. The first tooth and the tooth block of the first strap are correspondingly engaged, and the second tooth and the tooth block of the second strap are correspondingly engaged.

[0011] The first strap wraps around the sternum and is then inserted into the first channel, and the second strap wraps around the sternum and is then inserted into the second channel, forming an X-shaped binding structure.

[0012] Alternatively, the first channel can be positioned above the second channel.

[0013] The first strap and the fixing block are connected and fixed to one side of the partition plate extending in the second direction, and the first strap is located below the outlet side of the first channel;

[0014] The second strap and the connecting end of the fixing block are combined and fixed to one side of the fixing block extending in the first direction, and the second strap is located below the outlet side of the second channel.

[0015] Alternatively, the surface of the first strapping tape facing upwards towards the first channel is a smooth surface, while the surface facing upwards towards the second channel is provided with toothed blocks.

[0016] The second strap has toothed blocks on the side surface facing upwards towards the second channel, while the side surface away from the second channel is a smooth surface.

[0017] Alternatively, the tooth block may include intersecting inclined surfaces and straight surfaces.

[0018] Alternatively, the first locking tooth is formed by the portion of the partition plate near the entrance of the first channel protruding into the first channel and extending towards the exit of the first channel. The first locking tooth is inclined upward and divides the first channel into a first channel area and a first adjustment area, with the first adjustment area located between the first locking tooth and the partition plate.

[0019] The first strap is inserted into the first channel area. When the first strap passes through the first channel, the inclined surface of the toothed block of the first strap abuts against the first locking tooth. The first locking tooth is pushed into the first adjustment area by the forward movement of the inclined surface of the toothed block of the first strap.

[0020] Alternatively, the first locking tooth may be positioned on the side of the first channel outlet, with the first limiting surface being parallel to the side of the fixing block where the first channel outlet is located.

[0021] The first strap is inserted into the first channel, and the straight surface of the toothed block of the first strap abuts against the first limiting surface;

[0022] The angle at which the first tooth is tilted is the same as the angle at which the inclined surface of the tooth block located on the first strap is tilted.

[0023] Alternatively, the second locking tooth is formed by the portion of the partition plate near the entrance side of the second channel protruding into the second channel and extending towards the exit side of the second channel. The second locking tooth is inclined downward and divides the second channel into a second channel area and a second adjustment area, with the second adjustment area located between the second locking tooth and the partition plate.

[0024] The second strap is inserted into the second channel area. When the second strap passes through the second channel, the inclined surface of the toothed block of the second strap abuts against the second locking tooth. The second locking tooth is pushed into the second adjustment area by the forward movement of the inclined surface of the toothed block of the second strap.

[0025] Alternatively, the second locking tooth may have its end face near the outlet side of the second channel as the second limiting surface, and the second limiting surface and the side of the fixing block where the outlet side of the second channel are located are parallel.

[0026] The second strap is inserted into the second channel, and the straight surface of the toothed block of the second strap abuts against the second limiting surface;

[0027] The second tooth is tilted at the same angle as the inclined surface of the tooth block located on the second strap.

[0028] Alternatively, the cross-shaped biodegradable sternal fixation device may further include a tip structure, which is respectively attached to the end of the first strap and the second strap away from the fixation block.

[0029] Alternatively, the fixing block, the first strap, and the second strap can be made of polylactic acid or polycaprolactone.

[0030] The beneficial effects of this utility model are as follows:

[0031] To address the technical problems existing in the prior art, this utility model provides a cross-type biodegradable sternal fixation device. Through optimized design of the fixation block, the first strap, and the second strap, a single fixation block simultaneously locks the straps in two different directions, solving the problem that traditional sternal bandages cannot meet the required mechanical strength for sternal fixation. It also offers the advantages of quick and convenient installation, facilitating operation by medical personnel. The first and second straps form an X-shaped binding structure when binding the sternum, enabling fixation from multiple directions and ensuring the necessary mechanical strength for sternal fixation in both the lateral and longitudinal directions, reducing sternal displacement and deformation. Furthermore, this cross-type biodegradable sternal fixation device is made of biodegradable materials, allowing it to completely degrade within the human body, avoiding the need for a second surgery to remove the device and mitigating the risks associated with such procedures. In summary, this cross-type biodegradable sternal fixation device offers advantages such as high stability, high strength, high practicality, low risk, and promotion of wound healing. Attached Figure Description

[0032] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0033] Figure 1 This diagram illustrates the structure of the cross-type biodegradable sternal fixation device provided in an embodiment of the present invention.

[0034] Figure 2 This is a top view of the cross-type biodegradable sternal fixation device provided in an embodiment of the present invention.

[0035] Figure 3 Show Figure 2 Sectional view of AA.

[0036] Figure 4 Show Figure 2 A cross-sectional view of BB.

[0037] Figure 5 This diagram shows the first strap in a bundled state.

[0038] Figure 6 This diagram shows the second strap in a bundled state.

[0039] Figure 7 This diagram illustrates the use of a cross-type biodegradable sternal fixation device provided in an embodiment of the present invention to fix the sternum. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not the entire structure.

[0041] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0042] In this invention, unless otherwise expressly specified and limited, the first feature being "above" or "below" the second feature may include direct contact between the first and second features, or contact between the first and second features not being in direct contact but through another feature between them.

[0043] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0044] To address the shortcomings of existing technologies, this utility model provides a cross-type biodegradable sternal fixation device, combined with... Figure 1-7 As shown, the cross-type biodegradable sternal fixation device includes a fixation block 1 and a first strap 2 and a third strap 3 respectively attached to two adjacent sides of the fixation block 1.

[0045] The first strap 2 and the third strap 3 have the same structure, with one side surface including multiple evenly distributed toothed blocks 4 and the other side surface being a smooth surface.

[0046] The fixing block 1 has a cubic structure, including a first channel 11, a second channel 12, and a locking tooth structure located between the first channel 11 and the second channel 12. The first channel 11 extends along a first direction, and the second channel 12 extends along a second direction, with the first and second directions perpendicular to each other. It is understood that the first direction described in this embodiment is... Figure 1 The X-axis direction, the second direction is Figure 1 The Y-axis direction in the diagram.

[0047] The locking tooth structure is used to fix the first strap 2 and the third strap 3 within the first channel 11 and the second channel 12, respectively. The locking tooth structure includes a partition plate 13, a first locking tooth 14 protruding from the partition plate 13 into the first channel 11, and a second locking tooth 15 protruding from the partition plate 13 into the second channel 12. The first locking tooth 14 is correspondingly engaged with the toothed block 4 on the first strap 2 to limit the movement of the first strap 2; the second locking tooth 15 is correspondingly engaged with the toothed block 4 on the second strap 3 to limit the movement of the second strap 3.

[0048] During sternal fixation, the first strap 2 is wrapped around the sternum 100 and then inserted into the first channel 11; the second strap 3 is wrapped around the sternum 100 and then inserted into the second channel 12, forming a structure as follows: Figure 7 The X-shaped binding structure shown fixes the sternum from multiple directions, ensuring the mechanical strength required for fixation in the lateral and longitudinal directions, and reducing displacement and deformation of the sternum.

[0049] In a specific embodiment, such as Figure 1 As shown, the first channel 11 is located above the second channel 12. The connecting end of the first strap 2 and the fixing block 1 is fixed to one side of the partition plate 13 extending in the second direction. The first strap 2 is located below the outlet side A of the first channel 11. The connecting end of the second strap 3 and the fixing block 1 is fixed to one side of the fixing block 1 extending in the first direction. Specifically, the second strap 3 is fixed to the bottom wall of the fixing block 1, located below the outlet side B of the second channel 12.

[0050] During sternal fixation, the first strap 2 wraps downwards around the sternum 100, enters the first channel 11 from the entrance side C, and exits from the exit side A, where it is fixed in place by the contact of the toothed block 4 and the first locking tooth 14. The second strap 3 wraps downwards around the sternum 100, enters the second channel 12 from the entrance side D, and exits from the exit side B, where it is fixed in place by the contact of the toothed block 4 and the second locking tooth 15. In this embodiment, the surface of the first strap 2 facing the first channel 11 in the third-party upward direction is smooth, while the surface facing the second channel 12 is provided with the toothed block 4. The surface of the second strap 3 facing the second channel 12 in the third-party upward direction is provided with the toothed block 4, while the surface away from the second channel 12 is smooth. It can be understood that the third-party upward direction in this embodiment refers to... Figure 1 The Z-axis direction in the equation.

[0051] It should be noted that, in this embodiment, the side surface of the first strap 2 and the second strap 3 with the toothed block 4 includes a recessed groove 40, and the toothed block 4 is formed within the groove 40. This prevents excessive direct friction with human tissue during sternal fixation. In other embodiments, the protrusion 4 may also protrude from the surfaces of the first strap 2 and the second strap 3. This application does not impose specific limitations on this, and the design can be tailored to the actual situation.

[0052] In one specific embodiment, the tooth block 4 includes intersecting inclined surfaces 41 and straight surfaces 42. The inclined surfaces 41 press against the teeth as the strapping advances to allow the strapping to pass through smoothly. After the strapping reaches the appropriate position, the straight surfaces 42 and the ends of the teeth abut against each other to limit the strapping.

[0053] In one embodiment, such as Figure 4 As shown, the first locking tooth 14 protrudes into the first channel 11 from the portion of the partition plate 13 near the entrance side C of the first channel 11 and extends towards the exit side A of the first channel 11. The first locking tooth 14 is inclined upward, dividing the first channel 11 into a first channel area 111 and a first adjustment area 112. The first channel area 111 is located between the upper surface of the first locking tooth 14 and the top wall of the fixing block 1, and the first adjustment area 112 is located between the lower surface of the first locking tooth 14 and the partition plate 13.

[0054] The channel height L1 of the first channel area 111 corresponding to the outlet side A of the first channel 11 is less than the thickness d1 of the smooth surface of the first strap 2 at the intersection of the inclined surface 41 and the straight surface 42 of the toothed block 4. The first strap 2 is inserted into the first channel area 111. As the first strap 2 passes through the first channel area 111, the inclined surface of the toothed block 4 located on the first strap 2 abuts against the first locking tooth 14. The first locking tooth 14 is squeezed by the toothed block 4 and shifts into the first adjustment area 112, so that the first strap 2 can pass through smoothly. When the first strap 2 is adjusted to a suitable binding position, the tension on the first strap 2 is released, and the first locking tooth 14 springs back to its original position, locking the position of the first strap 2.

[0055] In this embodiment, the end face of the first locking tooth 14 near the outlet side A of the first channel 11 is the first limiting surface 141, and the first limiting surface 141 is parallel to the side of the fixing block 1 where the outlet side A of the first channel 11 is located. The first strap 2 is inserted into the first channel 11. After adjusting to a suitable binding position, the tension on the first strap 2 is released, and the first locking tooth 14 springs back to its original position. The straight surface 42 of the tooth block 4 abuts against the first limiting surface 141, locking the position of the first strap 2 so that the first strap 2 cannot move within the first channel 11, thereby achieving the purpose of fixing the sternum. Specifically, the tilt angle of the first locking tooth 14 is the same as the tilt angle of the inclined surface 41 of the tooth block 4 located on the first strap 2, so that one end of the first locking tooth 14 corresponding to the outlet side A of the first channel 11 can be engaged between the inclined surface 41 and the straight surface 42 of the adjacent tooth block 4, thereby limiting the first strap 2 and realizing the automatic locking function.

[0056] In one embodiment, the second locking tooth 15 is formed by the portion of the partition plate 13 near the inlet side D of the second channel 12 protruding into the second channel 12 and extending towards the outlet side B of the second channel 12. The second locking tooth 15 is inclined downward, dividing the second channel 12 into a second channel area 121 and a second adjustment area 122. The second channel area 121 is located between the lower surface of the second locking tooth 15 and the bottom wall of the fixing block 1, and the second adjustment area 122 is located between the upper surface of the second locking tooth 15 and the partition plate 13.

[0057] The channel height L2 of the second channel area 121 corresponding to the outlet side B of the second channel 12 is less than the thickness d2 of the smooth surface of the second strapping 3 at the intersection of the inclined surface 41 and the straight surface 42 of the toothed block 4. The second strapping 3 is inserted into the second channel area 121. As the second strapping 3 passes through the second channel area 121, the inclined surface of the toothed block 4 and the second locking tooth 15 located on the second strapping 3 abut against each other. The second locking tooth 15 is squeezed by the toothed block 4 and shifts into the second adjustment area 122, so that the second strapping 3 can pass through smoothly. When the second strapping 3 is adjusted to a suitable binding position, the tension on the second strapping 3 is released, and the second locking tooth 15 springs back to its original position, locking the position of the second strapping 3.

[0058] In this embodiment, the end face of the second locking tooth 15 near the outlet side B of the second channel 12 is the second limiting surface 151, and the second limiting surface 151 is parallel to the side of the fixing block 1 where the outlet side B of the second channel 12 is located. The second strap 3 is inserted into the second channel 12. After adjusting to a suitable binding position, the tension on the second strap 3 is released, and the second locking tooth 15 springs back to its original position. The straight surface 42 of the tooth block 4 and the second limiting surface 151 abut against each other, locking the position of the second strap 3 so that the second strap 3 cannot move within the second channel 12, thereby achieving the purpose of fixing the sternum. Specifically, the tilt angle of the second locking tooth 15 is the same as the tilt angle of the inclined surface 41 of the tooth block 4 located on the second strap 3, so that one end of the second locking tooth 15 corresponding to the outlet side B of the second channel 12 can be engaged between the inclined surface 41 and the straight surface 42 of the adjacent tooth block 4, thereby limiting the second strap 3 and realizing the automatic locking function.

[0059] In a specific embodiment, such as Figure 2 As shown, the cross-shaped biodegradable sternal fixation device also includes a tip structure 5, which is respectively attached to the ends of the first strap 2 and the second strap 3 away from the fixation block 1. The tip structure 5 is used to pass through the intercostal muscle tissue so that the first strap 2 and the second strap 3 can wrap around the sternum for sternal fixation. In this embodiment, the tip structure 5 is a stainless steel needle. The stainless steel needle has moderate rigidity, which ensures smooth passage through the muscle tissue, avoids bending or breakage of the needle, and improves the success rate and safety of the passage. Furthermore, the smooth surface of the needle reduces friction and damage to the muscle tissue during passage, thereby reducing the patient's pain.

[0060] In actual use, such as Figure 7 As shown, the tip structure 5 of the first strap 2 and the second strap 3 pierces the intercostal muscle tissue at the M and N positions of the patient, respectively, and then exits from the intercostal spaces at the P and Q positions. The tip structure 5 is cut off at the position where it connects with the toothed block 4. The first strap 2 and the second strap 3 are then inserted into the first channel 12 and the second channel 13 for fixation. During the fixation process, the tightness can be adjusted according to the width of the intercostal space of different patients. This cross-type biodegradable sternal fixation device will gradually decompose in the human body over time and does not require a second surgery to remove it.

[0061] In this embodiment, the fixing block 1, the first strap 2, the second strap 3, and the toothed block 4 disposed on the first strap 2 and the second strap 3 are all made of biodegradable materials. The biodegradable materials can be polylactic acid (PLA) or polycaprolactone (PCT). PLA is a green polymer material prepared from grains, possessing excellent biocompatibility and biodegradability. It can be degraded into carbon dioxide and water by microorganisms in nature, and is therefore widely used in the medical field. PCT is a polymer with good biodegradability. PCT has better elasticity and toughness than PLA, making it suitable for scenarios requiring high elasticity and more conducive to the automatic locking of the fixing block 1 to the first strap 2 and the second strap 3.

[0062] The cross-shaped biodegradable sternal fixation device provided in this embodiment of the invention, through optimized design of the fixation block, the first strap, and the second strap, achieves simultaneous locking of two straps in different directions by a single fixation block. This solves the problem that traditional sternal bandages cannot meet the required mechanical strength when fixing the sternum, and also has the advantages of quick and convenient installation, making it easy for medical staff to operate. The first and second straps form an X-shaped binding structure when binding the sternum, enabling fixation from multiple directions and ensuring the necessary mechanical strength for sternal fixation in both the lateral and longitudinal directions, reducing sternal displacement and deformation. Furthermore, this cross-shaped biodegradable sternal fixation device is made of biodegradable materials and can completely degrade within the human body, avoiding the need for a second surgery to remove the sternal fixation device and mitigating the risks associated with secondary surgery. In summary, this cross-shaped biodegradable sternal fixation device has the advantages of high stability, high strength, high practicality, low risk, and the ability to promote wound healing.

[0063] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of this utility model are still within the protection scope of this utility model.

Claims

1. A cross-type biodegradable sternal fixation device, characterized in that, include: A fixing block and a first and second straps respectively attached to two adjacent sides of the fixing block; The first and second straps have the same structure, with one side surface having multiple evenly distributed toothed blocks and the other side surface being a smooth surface; The fixing block includes a first channel, a second channel, and a toothed structure located between the first channel and the second channel, wherein the first channel extends along a first direction and the second channel extends along a second direction; The tooth structure includes a partition plate, a first tooth protruding from the partition plate into the first channel, and a second tooth protruding from the partition plate into the second channel. The first tooth and the tooth block of the first strap are correspondingly engaged, and the second tooth and the tooth block of the second strap are correspondingly engaged. The first strap wraps around the sternum and is then inserted into the first channel, and the second strap wraps around the sternum and is then inserted into the second channel, forming an X-shaped binding structure.

2. The cross-type biodegradable sternal fixation device according to claim 1, characterized in that, The first channel is located above the second channel; The first strap and the fixing block are connected and fixed to one side of the partition plate extending in the second direction, and the first strap is located below the outlet side of the first channel; The second strap and the connecting end of the fixing block are combined and fixed to one side of the fixing block extending in the first direction, and the second strap is located below the outlet side of the second channel.

3. The cross-type biodegradable sternal fixation device according to claim 1, characterized in that, The surface of the first strap facing upwards towards the first channel is smooth, while the surface facing towards the second channel is provided with toothed blocks. The second strap has toothed blocks on the side surface facing upwards towards the second channel, while the side surface away from the second channel is a smooth surface.

4. The cross-type biodegradable sternal fixation device according to claim 1, characterized in that, The tooth block includes intersecting inclined planes and straight planes.

5. The cross-type biodegradable sternal fixation device according to claim 4, characterized in that, The first tooth is formed by the portion of the partition plate near the entrance of the first channel protruding into the first channel and extending towards the exit of the first channel. The first tooth is inclined upward and divides the first channel into a first channel area and a first adjustment area. The first adjustment area is located between the first tooth and the partition plate. The first strap is inserted into the first channel area. When the first strap passes through the first channel, the inclined surface of the toothed block of the first strap abuts against the first locking tooth. The first locking tooth is pushed into the first adjustment area by the forward movement of the inclined surface of the toothed block of the first strap.

6. The cross-type biodegradable sternal fixation device according to claim 5, characterized in that, The end face of the first tooth near the outlet side of the first channel is the first limiting surface, and the first limiting surface is parallel to the side of the fixing block where the outlet side of the first channel is located. The first strap is inserted into the first channel, and the straight surface of the toothed block of the first strap abuts against the first limiting surface; The angle at which the first tooth is tilted is the same as the angle at which the inclined surface of the tooth block located on the first strap is tilted.

7. The cross-type biodegradable sternal fixation device according to claim 4, characterized in that, The second locking tooth is formed by the portion of the partition plate near the entrance side of the second channel protruding into the second channel and extending towards the exit side of the second channel. The second locking tooth is inclined downward and divides the second channel into a second channel area and a second adjustment area. The second adjustment area is located between the second locking tooth and the partition plate. The second strap is inserted into the second channel area. When the second strap passes through the second channel, the inclined surface of the toothed block of the second strap abuts against the second locking tooth. The second locking tooth is pushed into the second adjustment area by the forward movement of the inclined surface of the toothed block of the second strap.

8. The cross-type biodegradable sternal fixation device according to claim 7, characterized in that, The end face of the second tooth near the outlet side of the second channel is the second limiting surface, and the side of the fixing block where the second limiting surface and the outlet side of the second channel are located are parallel. The second strap is inserted into the second channel, and the straight surface of the toothed block of the second strap abuts against the second limiting surface; The second tooth is tilted at the same angle as the inclined surface of the tooth block located on the second strap.

9. The cross-type biodegradable sternal fixation device according to claim 1, characterized in that, The cross-shaped biodegradable sternal fixation device also includes a tip structure, which is respectively attached to the end of the first strap and the second strap away from the fixation block.

10. The cross-type biodegradable sternal fixation device according to claim 1, characterized in that, The fixing block, the first strap, and the second strap are made of polylactic acid or polycaprolactone.

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