A 3D printed hollow external fixation brace and its preparation method

Abstract

The present invention provides a 3D printed hollow external fixation brace and a preparation method thereof, belonging to the field of medical device technology, comprising a brace body, a medicine port reserved on the brace body, a brace block installed in the medicine port, and the pillars and the brace body connected via a connector; the connector comprises a connector piece, an upper connector module and a lower connector module; the upper connector module is installed on the connector piece, the upper connector module comprises an inner column, an outer shell and a stop unit, the inner column is installed in the outer shell, and the stop unit is installed in the inner column; the lower connector module is installed on the brace body, the lower connector module comprises a lower connector tube, a connector sleeve and a traction unit, and the lower connector tube is installed on the outer wall surface of the brace body. The present invention solves the problem that the current use of damaging external fixators for fixation is prone to infection, inconvenience in movement, muscle atrophy, poor patient experience, and certain medical risks.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and in particular relates to a 3D printed hollow external fixation brace and a preparation method thereof. Background Art

[0002] When a patient suffers a severe fracture, they need to undergo orthopedic surgery to reduce the fracture. After the surgery, they need to be fixed with an external fixator. The external fixator is an invasive fixation method that requires steel pins to pass through both ends of the bone for fixation.

[0003] Currently, damaging external fixators are used for fixation, which can easily cause infection, difficulty in movement, and muscle atrophy, and the patient experience is poor. If improperly cared for, it can easily cause complications such as pin tract infection and loosening, causing unnecessary pain to the patient. In addition to pin tract infection, external fixators may also cause complications such as delayed fracture healing, nonunion, and joint stiffness. These complications need to be discovered and treated by doctors in a timely manner, otherwise it will affect the healing of fractures and the recovery of limb function, and there are certain medical risks. Summary of the Invention

[0004] The present invention provides a 3D printed hollow external fixator and a preparation method thereof, which aims to solve the problem that the current use of damaging external fixators for fixation is prone to infection, inconvenience in movement, muscle atrophy, and poor patient experience. If improperly cared for, it is easy to cause complications such as needle tract infection and loosening, causing unnecessary pain to the patient. In addition to needle tract infection, the external fixator may also cause complications such as delayed fracture healing, nonunion, and joint stiffness. These complications need to be discovered and treated by doctors in a timely manner, otherwise they will affect the healing of the fracture and the recovery of limb function, and there are certain medical risks.

[0005] An embodiment of the present invention provides a 3D printed hollow external fixation brace, comprising a brace body, a medicine port reserved on the brace body, a brace block mounted in the medicine port, a plurality of pillars fixedly connected to the outer side of the brace block, and the pillars connected to the brace body via connectors;

[0006] The connecting piece includes a connecting piece, an upper connecting module and a lower connecting module;

[0007] The upper connecting module is mounted on the connecting piece, and the upper connecting module comprises an inner column, an outer shell, and a stop unit. The inner column is mounted in the outer shell, and the stop unit is mounted in the inner column.

[0008] The lower connecting module is mounted on the brace body, and comprises a lower connecting cylinder, a connecting sleeve, and a traction unit. The lower connecting cylinder is mounted on the outer wall of the brace body, the connecting sleeve is mounted in the lower connecting cylinder, and the connecting sleeve is mounted above the traction unit.

[0009] A connecting seat 1 is arranged around the connecting piece;

[0010] The two ends of the inner column pass through the connecting seat 1, and the inner column is reserved with a strip groove, a through-opening, channel 1, channel 2 and channel 3. The strip groove is reserved on both sides of the inner column, and the through-opening intersects with the vertical center line of the inner column. The two ends of the through-opening respectively pass through the corresponding strip groove. The lower end of the through-opening is reserved for channel 2. Channel 1 is reserved between the through-opening and channel 2. Channel 1 connects the through-opening and channel 2. Channel 3 is reserved on the side of the inner column, and channel 3 and channel 2 are connected to each other.

[0011] The outer shell is provided with a second connecting seat, a movable piece and a spiral beryllium copper wire. The second connecting seat is provided on both sides of the outer shell, and the movable piece is provided on both sides of the inner shell. The movable piece and the strip groove are movably connected. The spiral beryllium copper wire is provided between the outer shell and the connecting seat. A U-shaped opening is reserved on the second connecting seat, and a restraining groove is reserved on the movable piece.

[0012] Furthermore, the stop unit includes a stop bar, a movable column, a rotating disc, a rotating shell and two spiral beryllium copper wires, the stop bar and the through-hole are movably connected, the movable column and the first channel are movably connected, the rotating disc and the second channel are screwed together, the inner wall of the rotating shell and the inner column are screwed together, and the second spiral beryllium copper wire is installed between a pair of stop bars;

[0013] The end of the stop bar farther from the spiral beryllium copper wire is reserved with a wedge-shaped surface.

[0014] Furthermore, the rotating disc is provided with a skewed mouth 1 and a connecting rod, the skewed mouth 1 is reserved on the rotating disc, the skewed mouth 1 is movably connected to the movable column, the connecting rod is movably connected to the channel 3, and the rotating disc and the rotating shell are connected via the connecting rod.

[0015] Furthermore, cavity one, cavity two, a square groove, a circular groove, a strip opening, a connecting opening and a circular strip are arranged on the lower connecting tube. Cavity one is reserved at the end of the lower connecting tube close to the upper connecting module, and cavity two is reserved at the end of the lower connecting tube farther from the upper connecting module. Cavity one and cavity two are connected to each other. The circular strip is arranged at the position where cavity one and cavity two are connected. The square groove is reserved on the inner wall of cavity one. The square groove and connecting seat two are adapted to each other. The circular groove is reserved in the inner wall of the lower connecting tube. The circular groove and the square groove are connected to each other. The strip opening is reserved on the inner wall of cavity two. The circular groove and the strip opening are connected via the connecting opening.

[0016] Furthermore, the connecting sleeve and the annular groove are screwed together, and a circular opening, a docking opening and a second skewed opening are reserved on the connecting sleeve. The circular opening is reserved in the center of the connecting sleeve, the docking opening is reserved on both sides of the circular opening, and the second skewed opening is reserved on the connecting sleeve.

[0017] Furthermore, the traction unit includes a connecting bar, a traction column and a movable seat. The middle of the connecting bar is screwed to the side wall of the bar opening, the bottom of the connecting bar passes through the bar opening, the traction column is installed on the top of the connecting bar, the traction column passes through the connecting opening and the second skewed opening, and the movable seat and cavity two are movably connected.

[0018] Furthermore, circular piece 1, circular piece 2, a connecting frame and spiral beryllium copper wire 3 are installed on the movable seat, circular piece 1 is installed at one end of the movable seat close to the upper connecting module, circular piece 2 is installed below circular piece 1, the connecting frame is installed between circular piece 1 and circular piece 2, and the spiral beryllium copper wire 3 is installed between circular piece 2 and the bottom wall of cavity 2; a wedge-shaped surface 2 is reserved on the side wall of the connecting frame, and the wedge-shaped surface 2 is in contact with the side wall of the bottom of the connecting strip.

[0019] A method for preparing a 3D printed hollow external fixation brace comprises the above-mentioned 3D printed hollow external fixation brace and further comprises the following steps:

[0020] Step M1: Obtain medical imaging information of the fracture and soft tissue injury site;

[0021] Step M2: importing medical imaging information into a 3D reconstruction system to obtain a preliminary 3D model;

[0022] Step M3: Perform biomechanical analysis of the preliminary three-dimensional model using the finite element method and according to the first strength theory;

[0023] Step M4: Based on the biomechanical analysis, the preliminary three-dimensional model information of the 3D printed medical external fixation brace is updated to obtain the final three-dimensional model;

[0024] Step M5: performing layered slicing and printing path planning on the final 3D model;

[0025] Step M6: The final three-dimensional model is processed and printed using polylactic acid printing materials through a 3D printing process to obtain a brace body;

[0026] Step M7: Print the brace block using a 3D printing process according to the specifications of the medication port, then print the pillars on the brace block. Next, print the components of the connectors, and then assemble the components into an upper connector module and a lower connector module. Then, adhere the lower connector module and the connector piece to the brace body and the pillars, respectively. Finally, assemble the brace body and the brace block together using the upper connector module and the lower connector module.

[0027] Furthermore, the finite element analysis method in step M3 includes the following steps:

[0028] Step M31: Meshing: importing the preliminary three-dimensional model into finite element analysis software to mesh the model;

[0029] Step M32: Material property definition: create a new material after importing the model and assign elastic modulus, Poisson's ratio and density;

[0030] Step M33: Create and assign sections;

[0031] Step M34: Set loads and boundary conditions, and apply corresponding loads and boundary conditions to the outer surface of the brace according to the actual use of the brace and based on biomechanical analysis;

[0032] Step M35: Analysis and Solution. After applying loads and setting boundary conditions for the model, create and set a static analysis step for the simulation. Finally, create a new job, submit it, and wait for the software to run and output the results.

[0033] Furthermore, the biomechanical analysis in step M4 includes the following steps:

[0034] Step M41: Obtaining an optimization model, and obtaining an optimization model for biomechanical optimization design based on the finite element analysis results of the model under the conditions of step M3;

[0035] Step M42: Set the optimization response form, and set a single response or a combined response according to the required optimization content;

[0036] Step M43: Setting optimization parameters. After obtaining the optimization model of the optimal design, the optimization parameters of the model must be specifically set.

[0037] Step M44: Analysis and solution. After completing all optimization parameter settings for the model, submit and wait for the software to run and the final results to be output.

[0038] The beneficial effects of the present invention are:

[0039] The 3D printed hollow external fixation brace of the present invention replaces the external fixation bracket under specific circumstances (the specific circumstances here specifically refer to the absence of other open wounds, that is, there are no other large-area wound surfaces except the surgical incision) to fix the injured part with the surgical incision. After reserving a medicine port on the brace body, the brace block is assembled at the medicine port. When it is necessary to change the dressing, the brace block is disassembled and taken out, and the medicine port is opened to change the dressing. The brace block is provided with a support, a connecting piece and an upper connecting module on the lower connecting module on the outer wall of the brace body, so that the brace body and the brace block can be quickly assembled. After the upper connecting module is placed against the lower connecting module, it is pressed downward to achieve the purpose of tightening the connection. When it is necessary to change the dressing, the brace block is disassembled and taken out, and the medicine port is opened to change the dressing. When removing the brace block, only the rotating shell needs to be rotated to cancel the fastening connection. The connection and assembly are very convenient, and the brace block can be quickly disassembled to open the medicine port for dressing change. There is no need to drill holes on the skin of the upper and lower ends of the limb or fracture for fixation, which reduces the difficulty and risk of the operation. At the same time, the operation site can be isolated from the outside world, thereby reducing the risk of infection at the surgical incision. The entire external fixation brace is prepared by 3D printing, has a high aesthetics, and is convenient for daily work and life. The surgical incision is on the inside of the brace, which is not easy to touch and is not easy to cause pain in the wound. It improves the patient's medical experience and avoids the medical risks brought by traditional external fixators.

[0040] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the structures particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0042] Figure 1 The main structure of the embodiment of the present invention is shown as follows Figure 1 ;

[0043] Figure 2 The main structure of the embodiment of the present invention is shown as follows Figure 2 ;

[0044] Figure 3 Schematic diagram of the cross-sectional structure of the medicine feeding port according to an embodiment of the present invention;

[0045] Figure 4 A schematic structural diagram of an upper connection module and a lower connection module according to an embodiment of the present invention;

[0046] Figure 5This is a schematic diagram of the disassembled structure of the lower connection module according to an embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram of the disassembled structure of the upper connection module according to an embodiment of the present invention;

[0048] Figure 7 This is a schematic diagram of the inner column structure of an embodiment of the present invention;

[0049] Figure 8 Schematic diagram of the housing structure of an embodiment of the present invention;

[0050] Figure 9 A schematic diagram of the rotating shell structure according to an embodiment of the present invention;

[0051] Figure 10 A schematic diagram of the connection structure between the upper connection module and the lower connection module according to an embodiment of the present invention;

[0052] Figure 11 The displacement cloud diagram of the finite element analysis of the embodiment of the present invention;

[0053] Figure 12 This is a model diagram before biomechanical optimization design of an embodiment of the present invention;

[0054] Figure 13 This is a model diagram after biomechanical optimization design according to an embodiment of the present invention;

[0055] Figure 14 This is a diagram of the maximum tensile stress in the X direction of an embodiment of the present invention;

[0056] Figure 15 Graph showing the maximum tensile stress in the Y direction according to an embodiment of the present invention;

[0057] Figure 16 This is a diagram of the maximum tensile stress in the Z direction of an embodiment of the present invention;

[0058] 1. Brace body; 2. Medication port; 3. Brace block; 4. Pillar; 5. Connector; 51. Connecting piece; 52. Upper connecting module; 521. Inner column; 522. Outer shell; 523. Stop unit; 53. Lower connecting module; 531. Lower connecting cylinder; 532. Connecting sleeve; 533. Pulling unit; 511. Connecting seat 1; 5211. Strip groove; 5212. Through-hole; 5213. Channel 1; 5214. Channel 2; 5215. Channel 3; 5221. Connecting seat 2; 5222. Movable piece; 5223. Spiral beryllium copper wire 1; 5224. U-shaped opening; 5225. Constraint groove; 5231. Stop strip; 5232. Movable column; 5233, rotating disc; 5234, rotating shell; 5235, spiral beryllium copper wire (II); 5236, skewed opening (I); 5237, connecting rod; 5238, wedge-shaped surface (I); 5311, cavity (I); 5312, cavity (II); 5313, square groove; 5314, circular groove; 5315, strip opening; 5316, connecting opening; 5317, circular strip; 5321, circular opening; 5322, docking port; 5323, skewed opening (II); 5331, connecting strip; 5332, pulling column; 5333, movable seat; 5334, circular disc (I); 5335, circular disc (II); 5336, connecting frame; 5337, spiral beryllium copper wire (III); 5338, wedge-shaped surface (II). DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the technical solution of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of specific embodiments of the present invention. The same figure marks in the drawings represent the same components. It should be noted that the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] See Figures 1-10 The embodiment of the present invention provides a 3D printed hollow external fixation brace, comprising a brace body 1, a medicine port 2 reserved on the brace body 1, a brace block 3 installed in the medicine port 2, a plurality of pillars 4 fixedly connected to the outside of the brace block 3, and the pillars 4 are connected to the brace body 1 via a connector 5.

[0061] See Figure 1 and Figure 2 The medicine port 2 can be round, plum blossom-shaped, etc., and the brace block 3 is adapted to the medicine port 2.

[0062] See Figure 3-Figure 5 The connecting member 5 includes a connecting piece 51 , an upper connecting module 52 and a lower connecting module 53 .

[0063] The upper connecting module 52 is mounted on the connecting piece 51 and includes an inner column 521, an outer shell 522, and a stop unit 523. The inner column 521 is mounted in the outer shell 522, and the stop unit 523 is mounted in the inner column 521. The outer shell 522 is used to connect and fasten with the lower connecting module 53. The stop unit 523 fastens the outer shell 522 and the inner column 521 during connection. When disassembling, the stop unit 523 can also allow the outer shell 522 and the inner column 521 to disassemble.

[0064] The lower connecting module 53 is mounted on the brace body 1 and includes a lower connecting tube 531, a connecting sleeve 532, and a traction unit 533. The lower connecting tube 531 is mounted on the outer wall of the brace body 1, and the connecting sleeve 532 is mounted in the lower connecting tube 531. The connecting sleeve 532 is mounted above the traction unit 533. The traction unit 533 pulls the connecting sleeve 532 to rotate, and the traction unit 533 is pulled by the inner column 521 to move.

[0065] When assembling the brace block 3, the inner column 521 is connected to the lower connecting module 53. The inner column 521 pulls the traction unit 533 to move, and then the traction unit 533 pulls the connecting sleeve 532 to rotate, so as to achieve the purpose of connecting the connecting sleeve 532 and the outer shell 522. When the inner column 521 is embedded in the lower end of the lower connecting module 53, the stop unit 523 tightens the inner column 521 and the outer shell 522 to complete the connection with each other. When disassembling, the stop unit 523 is controlled to allow the inner column 521 and the outer shell 522 to disintegrate, and the upper connecting module 52 and the lower connecting module 53 disassemble themselves.

[0066] See Figure 4-10 Among them, a connecting seat 511 is installed around the connecting piece 51, which is used to fix a spiral beryllium copper wire 5223.

[0067] The two ends of the inner column 521 pass through the connecting seat 1 511. The inner column 521 is reserved with a strip groove 5211, a through-port 5212, a first channel 5213, a second channel 5214, and a third channel 5215. The strip groove 5211 is reserved on both sides of the inner column 521. The through-port 5212 intersects with the vertical center line of the inner column 521. The two ends of the through-port 5212 respectively pass through the corresponding strip groove 5211. The lower end of the through-port 5212 reserves the second channel 5214. The first channel 5213 is reserved between the through-port 5212 and the second channel 5214. The first channel 5213 connects the through-port 5212 and the second channel 5214. The third channel 5215 is reserved on the side of the inner column 521. The third channel 5215 and the second channel 5214 are connected to each other.

[0068] The strip groove 5211 is reserved at the head end of the inner column 521 , and the channel two 5214 and the channel three 5215 are reserved at the tail end of the inner column 521 .

[0069] The outer shell 522 is provided with a second connector 5221, a movable piece 5222, and a first spiral beryllium copper wire 5223. The second connector 5221 is provided on both sides of the outer shell 522, and the movable pieces 5222 are provided on both sides of the inner shell 522. The movable pieces 5222 are movably connected to the strip groove 5211. The first spiral beryllium copper wire 5223 is provided between the outer shell 522 and the first connector 511. The second connector 5221 is provided with a U-shaped opening 5224, and the movable piece 5222 is provided with a restraining groove 5225.

[0070] The movable piece 5222 and the strip groove 5211 are adapted to each other to ensure that the inner column 521 cannot rotate in the outer shell 522, and the U-shaped opening 5224 on the connecting seat 2 5221 and the lower connecting module 53 are adapted to achieve the purpose of connection; the constraint groove 5225 is used to cooperate with the stop unit 523 to achieve the purpose of tightening the outer shell 522 and the inner column 521.

[0071] The stop unit 523 includes a stop bar 5231, a movable post 5232, a rotating disc 5233, a rotating housing 5234, and a second spiral beryllium copper wire 5235. The stop bar 5231 is movably connected to the through-hole 5212, the movable post 5232 is movably connected to the first channel 5213, the rotating disc 5233 is screwed to the second channel 5214, and the inner wall of the rotating housing 5234 is screwed to the inner post 521. The second spiral beryllium copper wire 5235 is installed between the pair of stop bars 5231. The end of the stop bar 5231 farther from the second spiral beryllium copper wire 5235 is reserved with a first wedge-shaped surface 5238.

[0072] The stop bar 5231 is used to tighten the housing 522 during connection. Initially, the shape of the spiral beryllium copper wire 2 5235 does not change, the movable column 5232 is located at the end of the channel 1 5213 farther from the vertical center line of the rotating disc 5233, the wedge surface 1 5238 passes through the through-hole 5212, and the angle between the wedge surface 1 5238 and the side of the stop bar 5231 closer to the connecting seat 1 511 is less than 90 degrees.

[0073] The rotating disc 5233 is provided with an inclined opening 1 5236 and a connecting rod 5237. The inclined opening 1 5236 is reserved on the rotating disc 5233. The inclined opening 1 5236 is movably connected to the movable column 5232. The connecting rod 5237 is movably connected to the channel 3 5215. The rotating disc 5233 is connected to the rotating housing 5234 via the connecting rod 5237.

[0074] The connecting line at both ends of the skewed opening 5236 deviates from the radius of the rotating disc 5233. Initially, the movable post 5232 is located at the end of the skewed opening 5236 that is farther from the vertical center line of the rotating disc 5233. When the rotating shell 5234 is rotated, the movable post 5232 is brought closer to the vertical center line of the rotating disc 5233 through the skewed opening 5236, and then the stop bar 5231 is retracted into the through opening 5212. At this time, the spiral beryllium copper wire 5235 is compressed and shortened. When the rotating shell 5234 is released, the spiral beryllium copper wire 5235 returns to its original shape, and the stop bar 5231 passes through the through opening 5212 again.

[0075] Among them, the lower connecting tube 531 is provided with cavity 1 5311, cavity 2 5312, square groove 5313, circular groove 5314, strip opening 5315, connection opening 5316 and circular strip 5317. Cavity 1 5311 is reserved at the end of the lower connecting tube 531 close to the upper connecting module 52, cavity 2 5312 is reserved at the end of the lower connecting tube 531 farther from the upper connecting module 52, cavity 1 5311 and cavity 2 5312 are connected to each other, and circular strip 5317 is provided. At the position where cavity one 5311 and cavity two 5312 are connected, a square groove 5313 is reserved on the inner wall of cavity one 5311, the square groove 5313 and connecting seat two 5221 are adapted to each other, an annular groove 5314 is reserved in the inner wall of the lower connecting tube 531, the annular groove 5314 and the square groove 5313 are connected to each other, and a strip opening 5315 is reserved on the inner wall of cavity two 5312, the annular groove 5314 and the strip opening 5315 are connected via the connecting opening 5316.

[0076] The connecting sleeve 532 and the circular groove 5314 are screwed together. The connecting sleeve 532 is provided with a circular opening 5321, a docking opening 5322, and a second skewed opening 5323. The circular opening 5321 is provided in the center of the connecting sleeve 532, the docking openings 5322 are provided on both sides of the circular opening 5321, and the second skewed opening 5323 is provided on the connecting sleeve 532.

[0077] The structure of the docking interface 5322 and the square groove 5313 are adapted to the structure of the connecting seat 2 5221. At the beginning, the docking interface 5322 and the square groove 5313 overlap, and the connection lines at both ends of the skewed mouth 2 5323 deviate from the vertical center line of the connecting sleeve 532. At the beginning, the head of the skewed mouth 2 5323 farther from the vertical center line of the connecting sleeve 532 overlaps with the connecting port 5316.

[0078] The traction unit 533 includes a connecting bar 5331, a traction post 5332, and a movable seat 5333. The center of the connecting bar 5331 is screwed to the sidewall of the bar opening 5315. The bottom of the connecting bar 5331 passes through the bar opening 5315. The traction post 5332 is mounted on the top of the connecting bar 5331. The traction post 5332 passes through the connecting opening 5316 and the second skewed opening 5323. The movable seat 5333 is movably connected to the second cavity 5312.

[0079] At the beginning, the traction column 5332 is located at the end of the connecting port 5316 and the second skewed port 5323 that is farther from the vertical center line of the lower connecting tube 531, and the lower wall surface of the bottom of the connecting strip 5331 is parallel to the lower wall surface of the strip-shaped port 5315; when the connecting strip 5331 rotates around its rotation center, the traction column 5332 rotates in the connecting port 5316, and then the traction column 5332 changes in the second skewed port 5323, and then pulls the connecting sleeve 532 to rotate.

[0080] Circular piece 1 5334, circular piece 2 5335, connecting frame 5336, and spiral beryllium copper wire 3 5337 are mounted on movable seat 5333. Circular piece 1 5334 is mounted on the end of movable seat 5333 close to upper connecting module 52. Circular piece 2 5335 is mounted below circular piece 1 5334. Connecting frame 5336 is mounted between circular piece 1 5334 and circular piece 2 5335. Spiral beryllium copper wire 3 5337 is mounted between circular piece 2 5335 and the bottom wall of cavity 2 5312. Wedge-shaped surface 2 5338 is reserved on the side wall of connecting frame 5336, and wedge-shaped surface 2 5338 contacts the side wall of the bottom of connecting strip 5331.

[0081] The circular piece 2 5335 is used to assemble the spiral beryllium copper wire 3 5337 and pull the connecting bar 5331 back to its original position. The connecting frame 5336 is used to pull the connecting bar 5331 to rotate. At the beginning, the shape of the spiral beryllium copper wire 3 5337 does not change. The lower wall surface of the bottom of the connecting bar 5331 is in contact with the circular piece 2 5335. The installation of the wedge surface 2 5338 requires that when the movable seat 5333 moves downward, it can pull the top of the connecting bar 5331 and the traction column 5332 to rotate around the rotation center toward the vertical center line of the connecting cylinder 531.

[0082] During use, when assembling the support block 3, it is only necessary to make the connecting seat 2 5221 face the square groove 5313, and insert the upper connecting module 52 into the lower connecting module 53. When the bottom of the outer shell 522 is in contact with the circular strip 5317, the outer shell 522 stops moving downward. At this time, the bottom of the inner column 521 is in contact with the circular piece 1 5334, and the upper connecting module 52 is pressed downward. At this time, only the inner column 521 continues to move downward, and the movable seat 5333 is pulled to press the spiral beryllium copper wire 3 5337. During this period, the wedge surface 2 5338 presses one end of the bottom of the connecting strip 5331, so that the pulling column 5332 is in contact with the inclined mouth 2 5 323 and the vertical center line of the downward connecting tube 531 in the connecting port 5316 change, and then the connecting sleeve 532 is pulled to rotate, and then the docking port 5322 and the U-shaped port 5224 are moved apart, allowing the connecting sleeve 532 to tighten the outer shell 522. When the inner column 521 is embedded at the bottom, the pulling column 5332 is at one end of the vertical center line of the skew port 2 5323 close to the connecting sleeve 532, and the wedge-shaped surface 1 5238 on the stop bar 5231 is pressed by the movable piece 5222 and pressed into the constraint groove 5225, so as to achieve the purpose of tightening the inner column 521 and the outer shell 522. At this time, the support block 3 is assembled. When changing the dressing, the brace block 3 is removed and the upper connecting module 52 on the connecting piece 51 and the lower connecting module 53 on the brace block 3 are sequentially disengaged. The rotary shell 5234 is simply rotated to disengage the stop bar 5231 and the restraining groove 5225. With the cooperation of the first spiral beryllium copper wire 5223 and the third spiral beryllium copper wire 5337, the inner column 521 moves toward the side farther from the lower connecting module 53. The second circular piece 5335 presses the bottom of the connecting bar 5331, causing the connecting bar 5331 to return to its original position. This then pulls the connecting sleeve 532 back to its original position, thus achieving the purpose of disassembling the upper connecting module 52 and the lower connecting module 53. By sequentially performing the same action on the remaining upper connecting modules 52, the purpose of disassembling the brace block 3 can be achieved, and then the dressing of the affected area can be changed. After applying the dressing, the brace block 3 can be assembled according to the above steps. There is no need to drill holes on the skin of the upper and lower ends of the limb or the fracture for fixation, which reduces the difficulty and risk of the operation. At the same time, the operation site can be isolated from the outside world, thereby reducing the risk of infection at the surgical incision. The entire external fixation brace is prepared by 3D printing, has a high aesthetics, and is convenient for daily work and life. The surgical incision is on the inner side of the brace, which is not easy to touch and is not easy to cause pain at the wound.

[0083] A method for preparing a 3D printed hollow external fixation brace comprises the following steps:

[0084] Step M1: Obtain medical imaging information of the fracture and soft tissue injury site;

[0085] Collect relevant medical imaging information of medical 3D printed personalized external fixation braces, which can be obtained through MRI or other three-dimensional imaging technologies.

[0086] Step M2: importing medical imaging information into a 3D reconstruction system to obtain a preliminary 3D model;

[0087] Open the 3D reconstruction system, select the "Import Image Information" function, and then follow the system prompts to import the medical image information into the system. Preprocess the medical image information, including alignment and segmentation, to ensure data quality and prepare for 3D reconstruction. After the preprocessing is completed, start the 3D reconstruction. Depending on the system and algorithm used, generate a preliminary 3D model from the 2D image data. The preliminary 3D model needs to be further optimized and adjusted, including smoothing the surface, repairing holes, and optimizing the geometric structure to improve its quality. After completing the above steps, export the preliminary 3D model to stl or obj format for use in finite element analysis software, which involves saving the preliminary 3D model as a file and viewing it directly in the system or performing further analysis and processing.

[0088] Step M3: Perform biomechanical analysis of the preliminary three-dimensional model using the finite element method and according to the first strength theory;

[0089] The finite element analysis method comprises the following steps:

[0090] Step M31: Meshing: Import the preliminary 3D model into finite element analysis software (such as ANSYS or ABAQUS) and mesh the model. In principle, the model should be meshed using an appropriate mesh type and size to ensure a balance between calculation accuracy and efficiency. If no problems are found after inspection, proceed to the subsequent steps. If any problems exist, re-mesh the model.

[0091] Step M32: Define material properties. Create a new material after importing the model and assign elastic modulus, Poisson's ratio, and density to 2000 MPa, 0.34, and 1.25e, respectively. -9 T / mm 3 , these values ​​are the basic properties of PLA polylactic acid materials;

[0092] Step M33: Create and assign a section. Create a "Shell" section with the "Mean" type. Select the area to which the interface will be assigned. In the viewport, select the entire model with your mouse. Click Finish. Select the shell section created in the previous step as the section for the entire model. Enter a thickness of 4mm based on the actual size of the model.

[0093] Step M34: Set loads and boundary conditions. According to the actual use of the brace and based on biomechanical analysis, apply corresponding loads and boundary conditions to the outer surface of the brace, such as simulating the brace being subjected to the weight of the human body and the maximum single arm / leg force. According to the "Study on the Maximum Strength Characteristics of Different Body Parts of Adult Male Residents in my country", the maximum upper limb strength is 148.9 ± 29.0b, which can be derived as the maximum single arm strength of approximately 33.77 + 6.58kg, and the maximum lower limb strength is 260.9b ± 53.2b, which can be derived as the maximum single leg strength of approximately 59.53 + 12.06kg. The analysis is based on these loads to simulate the biomechanical environment of the actual use of the brace;

[0094] Step M34: Analysis and Solution. After applying loads and setting boundary conditions for the model, create and set a static analysis step for the simulation. Finally, create a new job, submit it, and wait for the software to run and output the results.

[0095] After the calculation is completed, the obtained data can be analyzed on the result interface, mainly analyzing the calculated stress cloud map and displacement cloud map.

[0096] In the stress cloud diagram, the stress distribution of the model can be determined. The location and magnitude of the maximum stress can be obtained. By comparing it with the yield strength of the material, it can be determined whether there is a risk of yielding or failure and whether the model has mechanical strength and stability.

[0097] The biomechanical analysis of the preliminary three-dimensional model according to the first strength theory is as follows:

[0098] The maximum tensile stress of the model in three directions is read from the finite element analysis results and compared with the tensile fracture strength of the material. This is used as the basis for determining whether the model is damaged. This analysis is more in line with the strength and damage of the model itself.

[0099] The maximum tensile stresses in the three directions are: the maximum tensile stress in the X direction is 8.897 MPa, the maximum tensile stress in the Y direction is 5.648 MPa, and the maximum tensile stress in the Z direction is 0 (because in this analysis the model is mainly under compression and there is no tension in the Z direction);

[0100] Depend on Figure 14 、 Figure 15 and Figure 16 It can be seen that the maximum tensile stress in the three directions is less than the tensile fracture strength of the PLA material (40-60 MPa). Therefore, the model will not be damaged under the action of the load, and the branch has mechanical strength and stability.

[0101] The failure mode of the hollow brace printed with PLA is brittle failure. The fourth strength theory mainly targets the yield failure of materials and is not suitable for finite element analysis of brittle failure. Therefore, the first strength theory, namely the maximum tensile stress theory, which targets brittle failure, was selected during the analysis process to improve the accuracy of the analysis results.

[0102] In the displacement cloud map, determine the distribution of model displacement, and read the position and size of the maximum displacement. According to the maximum displacement, evaluate the degree of model deformation and judge the impact of the deformation on the use function.

[0103] Reference Figure 11 The maximum displacement is located in the bright area in the figure, i.e., the proximal edge of the brace. The maximum displacement is 10.89 mm, which is less than 5% of the overall size of the brace and can be ignored. Therefore, the deformation of the brace under this load will not affect its function.

[0104] In summary, the results of finite element analysis can verify the design safety, and the design model can be further optimized based on the results of finite element analysis.

[0105] Step M4: Based on the biomechanical analysis, the preliminary three-dimensional model information of the 3D printed medical external fixation brace is updated to obtain the final three-dimensional model;

[0106] The biomechanical analysis comprises the following steps:

[0107] Step M41: Obtaining an optimization model, and obtaining an optimization model for biomechanical optimization design based on the finite element analysis results of the model under the conditions of step M3;

[0108] Step M42: Set the optimization response type. Set a single response or a combined response based on the desired optimization content. In the optimization design used in this patent, the specific optimization type is "topology optimization." To ensure the accuracy of the entire model, freeze the load area and boundary condition area of ​​the optimization model (i.e., ensure that these two areas will not be optimized to cause changes in the load and boundary conditions).

[0109] Step M43: Setting Optimization Parameters. After obtaining the optimized model of the optimal design, the optimization parameters of the model must be specifically set. Based on biomechanical analysis, one or more specific parameters of the model, such as strain energy, strain, stress, volume, and displacement, are constrained. For example, the optimization constraint is that the change in strain energy value is ≤ 150% of the strain energy under the initial load, and the volume size optimization is ≥ 50% of the initial volume, in order to control the optimization results.

[0110] Step M44: Analysis and solution. After completing all optimization parameter settings for the model, submit and wait for the software to run and the final results to be output.

[0111] The optimization result is based on the results of the finite element analysis before the optimization process in step M41, and the specific optimization parameter constraints in step M43. The model diagram before and after the biomechanical optimization design can be obtained. Figure 12 and Figure 13 The optimization results have greatly optimized the volume size of the model (mainly in terms of thickness) while keeping the strain energy within the constraint value (that is, ensuring that the model will not be damaged). This optimization makes the patented product more excellent in mechanical properties and further enhances the stability of the product. The optimized product has greatly reduced its volume and weight, and improved the use effect of the brace and the comfort of the patient.

[0112] Based on the biomechanical analysis in the above steps, the existing preliminary three-dimensional model data is used for the next step of analysis and design. The preliminary three-dimensional model data is processed and adjusted in the digital modeling software using the principles of 3D printing technology. The objects printed by the 3D printing process need to be simulated and analyzed in the modeling software. According to the simulation results and the needs of the biomechanical analysis, the preliminary three-dimensional model data is adjusted, including changing the shape and structure of the brace to optimize the biomechanical properties and adaptability of the brace. After repeated simulations and adjustments, the three-dimensional model data of the brace is finally determined. This step requires ensuring that the model data meets all design requirements and that the brace can be prepared in the 3D printing equipment.

[0113] Step M5: performing layered slicing and printing path planning on the final 3D model;

[0114] First, the final 3D model is imported into the slicing software. After importing, the model needs to be adjusted, such as scaling, rotating, or translating, to better suit the printer's printing requirements. Before slicing, some basic printing parameters need to be set, such as printing temperature, layer height, wall thickness, and infill density. These parameters will affect print quality and printing time, so they need to be adjusted according to actual needs and printer performance. Next, the model is layered. The software divides the model into a series of layers from top to bottom, each corresponding to the printer's printing plane. The thickness of the layer is determined by the "layer height" in the printing parameters, as the rationality of the layering directly affects print quality and printing efficiency. After the model is layered, the software generates a print path for each layer. This path instructs the printer how to move when printing each layer, including when to move to a new position and when to infill. After generating the print path, the software will optimize it to improve printing efficiency and reduce printing errors. At the same time, the user can preview the entire printing process to check for any adjustments that need to be made. Finally, the sliced ​​data is exported to the printer GCode format to obtain the final processed 3D model.

[0115] Step M6: The final three-dimensional model is processed and printed using polylactic acid printing materials through a 3D printing process to obtain the brace body 1;

[0116] When printing begins, the printer prints the brace layer by layer according to the final processed 3D model. During the 3D printing process, conventional printing parameters such as fill density, layer height, wall thickness, and printing temperature need to be set, as these parameters affect the final shape and performance of the brace. After printing is completed, the brace body 1 is obtained. Finally, the brace body 1 is quality inspected, including shape inspection and size measurement. The brace that passes the inspection is used for external fixation of the affected area.

[0117] Step M7: Print the brace block 3 using a 3D printing process according to the specifications of the medication port 2. Then print the pillar 4 on the brace block 3. Next, print the components of the connector 5. Then, assemble the components into the upper connector module 52 and the lower connector module 53. Then, adhere the lower connector module 53 and the connector piece 51 to the brace body 1 and the pillar 4, respectively. Finally, assemble the brace body 1 and the brace block 3 together through the upper connector module 52 and the lower connector module 53.

[0118] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A 3D printed hollow external fixation brace, comprising a brace body (1), characterized in that: A medicine-applying opening (2) is reserved on the brace body (1), a brace block (3) is installed in the medicine-applying opening (2), a plurality of pillars (4) are fixedly connected to the outer side of the brace block (3), and the pillars (4) are connected to the brace body (1) via a connecting piece (5); The connecting member (5) comprises a connecting piece (51), an upper connecting module (52) and a lower connecting module (53); The upper connecting module (52) is installed on the connecting piece (51), and the upper connecting module (52) includes an inner column (521), an outer shell (522), and a stop unit (523). The inner column (521) is installed in the outer shell (522), and the stop unit (523) is installed in the inner column (521); The lower connecting module (53) is mounted on the brace body (1), and the lower connecting module (53) comprises a lower connecting cylinder (531), a connecting sleeve (532), and a traction unit (533); the lower connecting cylinder (531) is mounted on the outer wall surface of the brace body (1), the connecting sleeve (532) is mounted in the lower connecting cylinder (531), and the connecting sleeve (532) is mounted above the traction unit (533); A connecting seat 1 (511) is arranged around the connecting piece (51); The two ends of the inner column (521) pass through the connecting seat (511), and the inner column (521) is reserved with a strip groove (5211), a through-port (5212), a channel one (5213), a channel two (5214) and a channel three (5215). The strip groove (5211) is reserved on both sides of the inner column (521), and the through-port (5212) intersects with the vertical center line of the inner column (521). The two ends of the through-port (5212) respectively pass through Corresponding to the strip-shaped groove (5211), the lower end of the through-opening (5212) reserves a second channel (5214), the first channel (5213) is reserved between the through-opening (5212) and the second channel (5214), the first channel (5213) connects the through-opening (5212) and the second channel (5214), the third channel (5215) is reserved on the side of the inner column (521), and the third channel (5215) and the second channel (5214) are connected to each other; The shell (522) is provided with a second connecting seat (5221), a movable sheet (5222) and a spiral beryllium copper wire (5223). The second connecting seat (5221) is provided on both sides of the outside of the shell (522), and the movable sheet (5222) is provided on both sides of the inside of the shell (522). The movable sheet (5222) and the strip groove (5211) are movably connected. The spiral beryllium copper wire (5223) is provided between the shell (522) and the first connecting seat (511). A U-shaped opening (5224) is reserved on the second connecting seat (5221), and a restraining groove (5225) is reserved on the movable sheet (5222). The stop unit (523) includes a stop bar (5231), a movable column (5232), a rotating disc (5233), a rotating shell (5234) and a second spiral beryllium copper wire (5235); the stop bar (5231) and the through-hole (5212) are movably connected; the movable column (5232) and the first channel (5213) are movably connected; the rotating disc (5233) and the second channel (5214) are screwed together; the inner wall of the rotating shell (5234) and the inner column (521) are screwed together; and the second spiral beryllium copper wire (5235) is arranged between a pair of stop bars (5231); The end of the stop bar (5231) farther from the second spiral beryllium copper wire (5235) is reserved with a wedge-shaped surface (5238).

2. The 3D printed hollow external fixator according to claim 1, characterized in that: The rotating disc (5233) is provided with a skewed opening 1 (5236) and a connecting rod (5237), the skewed opening 1 (5236) is reserved on the rotating disc (5233), the skewed opening 1 (5236) and the movable column (5232) are movably connected, the connecting rod (5237) and the channel 3 (5215) are movably connected, and the rotating disc (5233) and the rotating shell (5234) are connected via the connecting rod (5237).

3. The 3D printed hollow external fixator according to claim 2, characterized in that: The lower connecting tube (531) is provided with cavity one (5311), cavity two (5312), a square groove (5313), a circular groove (5314), a strip opening (5315), a connection opening (5316) and a circular strip (5317). Cavity one (5311) is reserved at the end of the lower connecting tube (531) close to the upper connecting module (52), and cavity two (5312) is reserved at the end of the lower connecting tube (531) farther from the upper connecting module (52). Cavity one (5311) and cavity two (5312) are connected to each other, and the circular strip (5317) is provided at the lower connecting tube (531). At the position where cavity one (5311) and cavity two (5312) are connected, the square groove (5313) is reserved on the inner wall of cavity one (5311), the square groove (5313) and the connecting seat two (5221) are adapted to each other, the annular groove (5314) is reserved in the inner wall of the lower connecting tube (531), the annular groove (5314) and the square groove (5313) are connected to each other, and the strip opening (5315) is reserved on the inner wall of cavity two (5312), and the annular groove (5314) and the strip opening (5315) are connected via the connecting opening (5316).

4. The 3D printed hollow external fixator according to claim 3, characterized in that: The connecting sleeve (532) and the annular groove (5314) are screwed together. A circular opening (5321), a docking opening (5322) and a second skewed opening (5323) are reserved on the connecting sleeve (532). The circular opening (5321) is reserved in the center of the connecting sleeve (532), the docking opening (5322) is reserved on both sides of the circular opening (5321), and the second skewed opening (5323) is reserved on the connecting sleeve (532).

5. The 3D printed hollow external fixator according to claim 4, characterized in that: The traction unit (533) includes a connecting bar (5331), a traction column (5332) and a movable seat (5333); the middle of the connecting bar (5331) is screwed to the side wall of the strip opening (5315); the bottom of the connecting bar (5331) passes through the strip opening (5315); the traction column (5332) is installed on the top of the connecting bar (5331); the traction column (5332) passes through the connecting opening (5316) and the second skewed opening (5323); and the movable seat (5333) and the second cavity (5312) are movably connected.

6. The 3D printed hollow external fixator according to claim 5, characterized in that: The movable seat (5333) is provided with a circular piece 1 (5334), a circular piece 2 (5335), a connecting frame (5336) and a spiral beryllium copper wire 3 (5337); the circular piece 1 (5334) is provided at one end of the movable seat (5333) close to the upper connecting module (52); the circular piece 2 (5335) is provided below the circular piece 1 (5334); the connecting frame (5336) is provided between the circular piece 1 (5334) and the circular piece 2 (5335); the spiral beryllium copper wire 3 (5337) is provided between the circular piece 2 (5335) and the bottom wall of the cavity 2 (5312); a wedge-shaped surface 2 (5338) is reserved on the side wall of the connecting frame (5336); the wedge-shaped surface 2 (5338) contacts the side wall of the bottom of the connecting strip (5331).

7. A method for preparing a 3D printed hollow external fixator, comprising the 3D printed hollow external fixator according to claim 1, characterized in that: It also includes the following steps: Step M1: Obtain medical imaging information of the fracture and soft tissue injury site; Step M2: importing medical imaging information into a 3D reconstruction system to obtain a preliminary 3D model; Step M3: Perform biomechanical analysis of the preliminary three-dimensional model using the finite element method and according to the first strength theory; Step M4: Based on the biomechanical analysis, the preliminary three-dimensional model information of the 3D printed medical external fixation brace is updated to obtain the final three-dimensional model; Step M5: performing layered slicing and printing path planning on the final 3D model; Step M6: The final three-dimensional model is processed and printed using polylactic acid printing materials through a 3D printing process to obtain a brace body (1); Step M7: Print the brace block (3) by 3D printing according to the specifications of the upper medicine port (2), then print the pillar (4) on the brace block (3), then print the components of the connecting piece (5), and then assemble the components into an upper connecting module (52) and a lower connecting module (53), and then adhere the lower connecting module (53) and the connecting piece (51) to the brace body (1) and the pillar (4) respectively. Finally, assemble the brace body (1) and the brace block (3) together through the upper connecting module (52) and the lower connecting module (53).

8. The method for preparing a 3D printed hollow external fixator according to claim 7, characterized in that: The finite element analysis method in step M3 includes the following steps: Step M31: Meshing: importing the preliminary three-dimensional model into finite element analysis software to mesh the model; Step M32: Material property definition: create a new material after importing the model and assign elastic modulus, Poisson's ratio and density; Step M33: Create and assign sections; Step M34: Set loads and boundary conditions, and apply corresponding loads and boundary conditions to the outer surface of the brace according to the actual use of the brace and based on biomechanical analysis; Step M35: Analysis and Solution. After applying loads and setting boundary conditions for the model, create and set a static analysis step for the simulation. Finally, create a new job, submit it, and wait for the software to run and output the results.

9. The method for preparing a 3D printed hollow external fixator according to claim 8, characterized in that: The biomechanical analysis in step M4 comprises the following steps: Step M41: Obtaining an optimization model, and obtaining an optimization model for biomechanical optimization design based on the finite element analysis results of the model under the conditions of step M3; Step M42: Set the optimization response form, and set a single response or a combined response according to the required optimization content; Step M43: Setting optimization parameters. After obtaining the optimization model of the optimal design, the optimization parameters of the model must be specifically set. Step M44: Analysis and solution. After completing all optimization parameter settings for the model, submit and wait for the software to run and the final results to be output.

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