阅读说明：本技术 一种用于大鼠股骨节段骨缺损的可调式外固定支架 (Adjustable external fixing support for rat femoral segmental bone defect ) 是由 陵廷贤 于 2019-11-07 设计创作，主要内容包括：本发明公开了一种用于大鼠股骨节段骨缺损的可调式外固定支架,包括钢板和多套定位件,所述定位件包括定位钉和固定帽,所述定位钉包括钉杆段和分别位于钉杆段两端的钉尖段和钉尾段,钉尖段为尖头螺纹结构,钉杆段为圆柱结构,且钉杆段上设置有受力凸台；所述固定帽固定在钉尾段上；所述钢板上沿钢板长度方向设置有两个相对称的定位孔,所述钢板通过定位孔分别固定在多套定位件的受力凸台与固定帽之间,且钢板与定位件之间的相对位置可调。本发明结构简单,拆装方便,固定后稳定性好,且在截骨范围较大时能够缩小截骨范围,改善了现有外固定支架的结构,能够达到简化手术方案、减少创伤和缩短手术时间的目的。(The invention discloses an adjustable external fixation support for rat femoral segmental bone defects, which comprises a steel plate and a plurality of sets of positioning pieces, wherein each positioning piece comprises a positioning nail and a fixing cap, each positioning nail comprises a nail rod section, a nail tip section and a nail tail section, the nail tip section and the nail tail section are respectively positioned at two ends of the nail rod section, the nail tip section is of a tip thread structure, the nail rod section is of a cylindrical structure, and a stress boss is arranged on the nail rod section; the fixing cap is fixed on the nail tail section; two symmetrical positioning holes are formed in the steel plate along the length direction of the steel plate, the steel plate is fixed between the stress bosses and the fixing caps of the multiple sets of positioning pieces through the positioning holes, and the relative position between the steel plate and the positioning pieces is adjustable. The external fixation bracket has the advantages of simple structure, convenience in disassembly and assembly, good stability after fixation, capability of reducing the osteotomy range when the osteotomy range is larger, improvement on the structure of the existing external fixation bracket, and capability of achieving the purposes of simplifying an operation scheme, reducing trauma and shortening operation time.)

1. An adjustable external fixation support for rat femoral segmental bone defect is characterized in that: the steel plate positioning device comprises a steel plate (1) and a plurality of sets of positioning pieces, wherein each positioning piece comprises a positioning nail (2) and a fixing cap (3), each positioning nail (2) comprises a nail rod section (4), a nail tip section (5) and a nail tail section (6) which are respectively positioned at two ends of the nail rod section (4), the nail tip section (5) is of a pointed thread structure, the nail rod section (4) is of a cylindrical structure, and a stress boss (7) is arranged on the nail rod section (4); the fixing cap (3) is fixed on the nail tail section (6); two symmetrical positioning holes (8) are formed in the steel plate (1) along the length direction of the steel plate (1), the steel plate (1) is fixed between the stress bosses (7) and the fixing caps (3) of the multiple positioning pieces through the positioning holes (8), and the relative position between the steel plate (1) and the positioning pieces is adjustable.

2. The adjustable external fixation frame for rat femoral segmental bone defects according to claim 1, wherein: nail tail section (6) are cylindrical thread structure, and the quantity of locking cap (3) is two, and two locking caps (3) are provided with levogyration internal thread and dextrorotation internal thread respectively, and two locking caps (3) are respectively through levogyration internal thread and dextrorotation internal thread to be fixed and form locking structure on nail tail section (6).

3. The adjustable external fixation frame for rat femoral segmental bone defects according to claim 1, wherein: the stress boss (7) is of a square structure, and the height of the stress boss (7) is 2 mm.

4. An adjustable external fixation frame for rat femoral segmental bone defects according to any one of claims 1-3, wherein: the number of the positioning pieces in the two positioning holes (8) is the same.

5. The adjustable external fixation frame for rat femoral segmental bone defects according to claim 1, wherein: the number of the positioning pieces is even, and at least four positioning pieces are provided.

6. The adjustable external fixation frame for rat femoral segmental bone defects according to claim 1, wherein: the length of the positioning nail (2) is 25mm, the diameter is 1.2mm, the length of the nail tip section (5) is 5mm, the length of the nail rod section (4) is 12mm, and the length of the nail tail section (6) is 8 mm.

7. The adjustable external fixation frame for rat femoral segmental bone defects according to claim 1, wherein: the steel plate (1) is of a round-corner rectangular structure, and the length, the width and the height of the steel plate (1) are respectively 25mm, 3.5mm and 1.5 mm.

8. The adjustable external fixation frame for rat femoral segmental bone defects according to claim 1, wherein: the positioning holes (8) are of round-angle rectangular structures, the length and the width of the positioning holes (8) are respectively 8mm and 1.3mm, and the distance between the two positioning holes (8) is 5 mm.

Technical Field

The invention belongs to the field of animal medical instruments, and particularly relates to an adjustable external fixing support for rat femoral segmental bone defects.

Background

The incidence of bone defects caused by infection, trauma, tumor and other causes is on the increasing trend year by year, and the treatment of bone defects is an important challenge for orthopedists. Autologous or allogeneic bone transplantation is the gold standard for treating bone defects, but the wide application of the autologous or allogeneic bone transplantation is limited due to the defects of limited supply, supply area complications, spread diseases, immune rejection, poor osseointegration and the like. The search for suitable bone graft substitutes is currently a focus and a major direction in the field of orthopedic research.

The SD rat femoral segment bone defect model is one of important means for evaluating the biosafety in a bone graft substitute and promoting the bone defect repair capacity, and the successful construction of the model has important influence on the accurate evaluation of the performance of the bone graft substitute. Meanwhile, the evaluation of these properties is an essential link for the development of bone graft substitutes from basic research to clinical transformation. At present, a tool commonly used for constructing a femoral segmental bone defect model is a steel plate screw internal fixation system, wherein the length of a steel plate is about 25mm, the width of the steel plate is about 3.5mm, and two ends with the height of about 2mm are respectively provided with 2-4 holes with threads along a longitudinal axis and are matched with screw threads. Rat femoral segmental bone defect model construction process based on steel plate screw internal fixation system: after rat anesthesia, the lateral position, along thigh anterolateral incision skin, expose the thighbone, hug closely thighbone anterolateral cortex and place the steel sheet, the steel sheet is fixed temporarily, along steel sheet both ends hole down on the thighbone cortex predrilling, wear to break two side cortices after, keep the steel sheet position unchangeable, the installation of fixed system is accomplished to downthehole screw of putting into, at the last thighbone of the required length of steel sheet mid portion intercepting, accomplish the construction of rat femoral condyle segmental bone defect model.

The rat femoral segmental bone defect model construction technology based on the steel plate screw internal fixation system can realize stable fixation of the femur, meets the basic requirements of bone graft substitute performance evaluation, and has the following defects at the same time:

1. the internal fixation steel plate is tightly attached to the anterior and lateral cortex of the femur, a long incision is needed, the muscle is widely stripped, the femur is exposed in a large range, the bone cortex and peripheral blood vessels of the femur are damaged more, the femoral blood supply and the repair of bone defect are influenced, the evaluation of the bone defect repairing capability of a bone graft is inaccurate, and the final experimental result is influenced.

2. The bone graft material at the bone defect part is directly contacted with the steel plate at the upper part except that two ends of the bone graft material are contacted with the broken ends of the thighbone, the steel plate belongs to an in-vitro foreign body, and the generated immunoreaction influences the local microenvironment required by the healing of the bone defect and also influences the final experimental result.

3. The operation process is complex, the operation time is long, and the death rate of the rat after the operation is increased. The steel sheet is at first required to be used the steel sheet to carry out the predrilling from foraminiferous mark to the thighbone during installation, puts the nail after all predrilling finish, and this stage needs the temporary fixation steel sheet, guarantees that the relative position of steel sheet and thighbone is unchangeable, and this point is accomplished hardly among the actual operation process for the steel sheet takes place the skew from the predrilling position on foraminiferous and the thighbone cortex when putting the nail, need adjust repeatedly, and it is very big to put the nail degree of difficulty. The osteotomy is performed after the fixing system in the steel plate screw is installed, but the steel plate is tightly attached to the surface of the femoral cortex at the moment, the femur is positioned below the steel plate, the position is deep, the osteotomy difficulty is high, the time is long, and peripheral vascular nerves are easily damaged.

4. The adjustment of the bone defect range after the osteotomy is completed can only be realized by osteotomy again, and only the increase of the bone defect range can not be reduced, and the adjustment of the bone defect range under the condition of overlarge osteotomy range can not be flexibly realized.

5. The evaluation of the bone graft capability of repairing bone defect requires taking out the rat femur specimen after repair, dismantling the internal fixed support, and carrying out related detection such as tissue section and the like. But the sample thighbone after growing is closely connected with the steel plate, the part of the screw protruding out of the steel plate is too short to be taken out easily, the internal fixation is very difficult to remove, the healed thighbone is often caused to break again, and the experiment success is short for one step.

Publication No. CN 110301993A's literature discloses a simple and easy type multipurpose rat femur external fixation frame, and it includes plastics external fixation frame splint, installation screw and kirschner wire, the installation locating hole has been seted up to plastics external fixation frame splint avris, the kirschner wire is installed in the installation locating hole, the screw mounting hole has been seted up to plastics external fixation frame splint top, the installation screw is installed inside the screw mounting hole, the kirschner wire adopts the 1.2mm diameter screw thread kirschner wire. The patent can basically meet the fixation requirements of rat femoral fracture, bone nonunion and bone defect experiments theoretically, and avoids the defect that the muscle around the femur needs to be widely stripped when an internal fixation steel plate is installed. However, the practical application finds that the following defects exist:

1, the tail end of the Kirschner wire is of a smooth structure, and is fixed only by two plastic plates in a pressurizing manner, so that the fixing strength is obviously insufficient, and the looseness of the external fixing support is easily caused when a rat moves.

2, the middle part and the tail end of the Kirschner wire are of smooth structures, and stress cannot be conducted, so that the needle placing and taking cannot be effectively realized.

3, must require to be parallel to each other between the kirschner wire, and just can put into the splint recess with the kirschner wire with splint keep perpendicularly and install fixedly, but put the needle in-process in reality and hardly guarantee that four kirschner wires are parallel to each other, and the needle inlet point is located same straight line and perpendicular with solid fixed splint, if put the needle and have the deviation side slightly to adjust repeatedly, the installation of outer fixed bolster is very loaded down with trivial details, and adjust the kirschner wire position repeatedly and can destroy thighbone kirschner wire way, make the kirschner wire hold power decline, thereby make outer fixed bolster installation failure.

4, after the whole bracket is fixed, the kirschner wire and the fixed splint are fixed, if the osteotomy range is too large during osteotomy, the osteotomy range cannot be reduced, and the model building fails.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides an adjustable external fixing support for rat femoral segmental bone defects, which has the advantages of simple structure, convenience in disassembly and assembly and good stability after fixation, can reduce the osteotomy range when the osteotomy range is larger, improves the structure of the conventional external fixing support, and can achieve the purposes of simplifying an operation scheme, reducing trauma and shortening operation time.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an adjustable external fixation support for rat femoral segmental bone defects comprises a steel plate and a plurality of sets of positioning pieces, wherein each positioning piece comprises a positioning nail and a fixing cap, each positioning nail comprises a nail rod section, a nail tip section and a nail tail section, the nail tip section and the nail tail section are respectively positioned at two ends of the nail rod section, the nail tip section is of a pointed thread structure, the nail rod section is of a cylindrical structure, and a stress boss is arranged on the nail rod section; the fixing cap is fixed on the nail tail section; two symmetrical positioning holes are formed in the steel plate along the length direction of the steel plate, the steel plate is fixed between the stress bosses and the fixing caps of the multiple sets of positioning pieces through the positioning holes, and the relative position between the steel plate and the positioning pieces is adjustable.

The nail tail section is cylindrical thread structure, and the quantity of locking cap is two, and two locking caps are provided with levogyration internal thread and dextrorotation internal thread respectively, and two locking caps form locking structure on the nail tail section through levogyration internal thread and dextrorotation internal thread respectively.

The stress boss is of a square structure, and the height of the stress boss is 2 mm.

The number of the positioning pieces in the two positioning holes is the same.

The number of the positioning pieces is even, and at least four positioning pieces are provided.

The length of location nail is 25mm, and the diameter is 1.2mm, and the length of nail point section is 5mm, and the length of nail pole section is 12mm, and the length of nail tail section is 8 mm.

The steel sheet is fillet rectangle structure, and the length, width and height of steel sheet are 25mm, 3.5mm and 1.5mm respectively.

The locating hole is round angle rectangle structure, and the length and width of locating hole is 8mm and 1.3mm respectively, and the interval between two locating holes is 5 mm.

The invention has the advantages that:

the invention 1, the steel plate and many sets of locating pieces make up, the steel plate is fixed between stressed boss and fixed cap of many sets of locating pieces separately through the locating hole, and the relative position between locating piece and the steel plate is adjustable. The steel plate has the advantages that the steel plate has higher strength, the stability after the steel plate is fixed with the positioning piece is good, and the whole outer bracket cannot be loosened after being fixed. The second advantage is that the structure is simple and the assembly and disassembly are convenient. The third advantage lies in can effectively conduct axial pressure and revolving force through the atress boss, can realize putting the nail fast and get the nail, is favorable to shortening operation time and later stage external fixation support demolish. The fourth advantage lies in that the relative position between steel sheet and the setting element is adjustable, allows to put during the in-service use that nail direction and position have certain deviation, and the location nail that does not need many sets of setting element must just can stabilize fixedly perpendicularly, and can adjust the point of advancing in a flexible way, can simplify the installation operation flow of putting nail and outer fixed bolster by a wide margin. The bone cutting range can be reduced by adjusting the relative position between the positioning piece and the steel plate when the bone cutting range is too large, so that the success of one-time model establishment is ensured. In addition, the invention has the advantages of simple structure, convenient assembly and disassembly, good stability after fixation and the like, can eliminate the influence of local foreign matters on the bone defect repair microenvironment, and increases the objectivity and accuracy of the evaluation of the bone graft repair bone defect capability.

2, the invention has less scope of stripping muscle around the femur during the operation, small operation wound and less influence on the blood supply of the femur; the fixed steel plate is positioned outside the body, and the bone grafting material at the bone defect part is not contacted with foreign matters outside the body, so that the influence on the bone repair microenvironment is avoided; the bracket has simple mounting steps and convenient operation, has better acceptance for the change of the nail direction, is convenient for osteotomy, shortens the operation time and has good fixation stability; the length of the bone defect after osteotomy can be flexibly adjusted; the external fixing bracket is convenient to dismantle and is not easy to damage the local structure.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of the positioning pin of the present invention;

FIG. 3 is a schematic structural view of a steel plate according to the present invention;

FIG. 4 is a Micro-CT scan reconstruction of a femoral segment of a rat in which the present invention is practiced;

FIG. 5 is a cross-sectional view of the Micro-CT of FIG. 4;

labeled as: 1. the steel sheet 2, the location nail, 3, the locking cap, 4, the nail pole section, 5, the nail point section, 6, the nail tail section, 7, atress boss, 8, locating hole.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

As shown in figure 1, the invention discloses an adjustable external fixation support for rat femoral segmental bone defects, which comprises a steel plate 1 and a plurality of sets of positioning pieces, wherein each positioning piece comprises a positioning nail 2 and a fixing cap 3, and each positioning nail 2 comprises a nail rod section 4 and a nail tip section 5 and a nail tail section 6 which are respectively positioned at two ends of the nail rod section 4. Wherein, the nail tip section 5 is of a tip thread structure and corresponds to the femur section; the nail tail section 6 is of a cylindrical thread structure and corresponds to the end of the steel plate 1; the nail rod section 4 is of a cylindrical structure, and a stress boss 7 for applying force to tools such as a wrench is arranged on the nail rod section 4. The fixing cap 3 is fixed on the nail tail section 6; two symmetrical positioning holes 8 are formed in the steel plate 1 along the length direction of the steel plate 1, the steel plate 1 is fixed between the stress bosses 7 and the fixing caps 3 of the multiple positioning pieces through the positioning holes 8, and the relative position between the steel plate 1 and the positioning pieces is adjustable. The number of the positioning pieces is even, and at least four positioning pieces are provided. Specifically, the number of positioning members passing through the two positioning holes 8 is preferably the same.

As shown in fig. 2, the positioning nail 2 is made of titanium alloy material, the length of the positioning nail is about 25mm, the diameter of the positioning nail is about 1.2mm, the length of the nail tip section 5 is about 5mm, and a 1.1 x 0.25mm pointed thread structure can penetrate through cortex on both sides of rat femur to form a stable structure with good holding force. The length of the nail rod section 4 is about 12mm, and the nail rod section plays a role in connection. The stress boss 7 is arranged on the nail rod section 4 close to the nail tail section 6, and the stress boss 7 is preferably of a tetragonal structure with the length of 1.5mm, the width of 1.5mm and the height of 2 mm; the nail rod section has two functions, on one hand, the structure of the nail rod section is matched with a wrench, the transmission device is a transmission device for rotating force and longitudinal pressure when nails are placed or taken out, on the other hand, the part of the nail rod section protruding out of the nail rod section 4 is used as a contact point with the bottom surface of the steel plate 1, and the fixing cap 3 and the fixing cap participate in fixing the steel plate 1 and the positioning nail 2 together. The length of the nail tail section 6 is about 8mm, the flat head thread structure of 1.1 x 0.25mm, and the nail tail section 6 penetrates through the positioning hole 8 on the steel plate 1 to be connected with the steel plate 1.

As shown in FIG. 3, the titanium alloy material of the steel plate 1 has a rounded rectangular structure, and the length, width and height of the steel plate 1 are respectively 25mm, 3.5mm and 1.5 mm. The locating hole 8 is the rounded rectangle structure, and forms along the fretwork of 1 axis both sides of steel sheet, and the length and width of locating hole 8 is 8mm and 1.3mm respectively, and the interval between two locating holes 8 is 5 mm. The tail section 6 of the positioning nail 2 passes through the positioning hole 8 and fixes the steel plate 1 together with the fixing cap 3. The hollow structure design of the steel plate 1 enables the position of the nail tail section 6 in the middle of the hollow to be adjusted according to actual conditions so as to achieve the purpose of optimal fixation, and the distance between the two middle positioning nails 2 is larger than 5mm, so that a certain space is reserved for osteotomy.

In the invention, the fixing cap 3 can adopt a nut structure so as to be fixed on the nail tail section 6 through threads. The outer diameter of the fixing cap 3 is an equihexagonal shape with the side length of 1.2mm, the inner diameter is a circular shape with the diameter of 1.2mm, and the thickness is about 1 mm. Specifically, the number of the fixing caps 3 is two, the two fixing caps 3 are respectively provided with a left-handed internal thread and a right-handed internal thread, and the two fixing caps 3 are respectively fixed on the nail tail section 6 through the left-handed internal thread and the right-handed internal thread to form a locking structure. The structure that adopts two locking caps to cooperate has the locking function, can prevent that locking cap 3 from taking place to become flexible in the implementation.

The invention has better acceptance to the direction change of the nail, allows slight forward tilting or side tilting on the basis of ensuring that the nail tail section 6 can pass through the positioning hole 8 on the steel plate 1, and can lock the nail tail section 6 as long as the nail tail section can pass through the steel plate 1. In addition, in order to obtain the best holding force, the nail placing depth of each positioning nail 2 is different, and after the nail is placed, the nail tail section 6 with the lower position of the stress boss 7 on the nail rod section 4 is found to be firstly screwed into the fixing cap 3, so that the upper edge of the fixing cap 3 and the stress bosses 7 on the rest nail rod sections 4 are positioned on the same horizontal plane, and then the steel plate 1 is arranged for locking. If the osteotomy range is too small after the primary fixation is finished, the osteotomy can be continued to meet the requirement by using the abrasive drill, if the osteotomy range is too large, the fixing cap 3 can be slightly unscrewed, the positioning nail 2 is properly pressed towards the middle in the two positioning holes 8, the thighbones at the two sides are close to each other, and the left-handed fixing cap 3 is screwed down after the bone defect range meets the requirement and then is locked. When the external fixing bracket is disassembled, the fixing cap 3 is firstly disassembled, the steel plate 1 is taken down, and the positioning nail 2 is taken out by a spanner, so that the external fixing bracket can be disassembled. In a word, the external fixing bracket system has the characteristics of simple installation and removal, flexible adjustment, good fixing stability and the like.

A5 mm rat femoral segmental bone defect model is constructed based on the external fixation support, and the specific operation steps are as follows:

the first step is as follows: the rat is anesthetized and then the lateral position is taken, skin preparation and disinfection are carried out, then skin, subcutaneous tissue and muscle layers are cut along the outer side of the femur layer by layer, the outer cortex of the middle section of the femur is exposed, and the muscle attached to the osteotomy part is stripped. The 5mm osteotomy length is marked in the middle of the femur, and the nail feeding point is determined on the femoral medial axis at about 2mm and 7mm positions on both sides of the marked osteotomy position. And (5) stripping muscles and periosteum at the nail feeding point, and performing ordinary 1.0mm abrasive drilling and punching positioning.

The second step is that: the nails are sequentially arranged in the direction perpendicular to the lateral cortex of the femur by using a spanner, and the nail arrangement is completed after the positioning nail 2 passes through the cortex of the opposite side and well holds the femur. Observing the nail placing depth of the four positioning nails 2, if the depths are different, adjusting the nail placing depth to avoid influencing the holding force of the positioning nails 2, screwing the nut into the tail section 6 of the deeper positioning nail 2 to ensure that the upper edge of the nut and the upper edges of the other square bodies of the positioning nails 2 are on the same horizontal plane. The nail tail section 6 of the positioning nail 2 is arranged in the steel plate 1, the bottom surface of the steel plate 1 is attached to the stress boss 7 or the upper edge of the increased nut, the two fixing caps 3 are screwed in the nail tail section 6 in sequence, the steel plate 1 is fixed through pressurization, and the installation of the outer fixing support is completed.

The third step: utilizing a grinding drill or a grinding saw to cut the 5mm bone defect according to the mark, and if the bone defect is smaller after the bone cutting is finished, continuing to cut the bone to 5mm by utilizing the grinding drill; if the range of bone cutting is too large, the fixing cap 3 on the upper edge of the steel plate 1 can be unscrewed, the thighbones on the two sides are close by inward pressurization, the fixing cap 3 is screwed when the bone defect is adjusted to be 5mm, after the size of the range of the bone defect is determined to be proper, the dextrorotation fixing cap 3 is screwed in the nail tail section 6 in sequence for locking, and the construction of the bone defect model of the femoral segment of the rat is completed. And (5) suturing the wound layer by layer after the bone graft substitute is placed, and finishing the operation. As shown in FIGS. 4 and 5, the reconstruction and the sectional views of the Micro-CT scanning are shown when the invention is practically applied to rat femur segments.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.