intramedullary needle fixation

Intramedullary needle internal fixation is mostly used for long bone fractures (such as femoral, hernia, ulnar, ankle, humerus, etc.). The advantage is that the intramedullary needle itself is relatively firm and firm, and can be used less or without external fixation after surgery, which is beneficial to the early active exercise of the injured limb; the skin incision is small, the periosteal peeling range is limited, and the damage is small; the intramedullary needle is long Different shapes and angles, embedded in the medullary cavity, can achieve a firm internal fixation, which can avoid the occurrence of rotation, lateral displacement and angular displacement. The disadvantage is that it requires a certain amount of equipment and the operation is complicated. Fixing the fracture of the long tube with an intramedullary needle is like using a shaft to pass through two bamboo tubes. If the outer diameter of the intramedullary needle is equal to the inner diameter of the length of the bone, the fixation is good, and the alignment and alignment can be stably maintained. A fracture occurs in the narrowest segment of the long bone (such as the ulna, middle tibia, femur, tibia, and tibia). The corresponding width of the intramedullary needle can be directly embedded in the cortex around the medullary cavity. On the inner layer of the bone, the cross section of the needle can be used for a good elastic fixation, and the ends of the needle can be fixed on the cancellous bone or the cortical bone at the needle to prevent various displacements, which is ideal. Internal fixation. When the fracture occurs in the non-stenosis of the long bone, although it can not rely on the direct elastic fixation of the intramedullary nail, it can rely on the fixation of the upper, middle and lower points to achieve the stability of the fracture [Fig. 1]. The types of intramedullary needles are plum, v, rhombus, triangle and round. For the femoral, temporal, and ulna, the intramedullary nail should be used. The advantages of plum-shaped and v-shaped intramedullary needles are that the medullary cavity is less damaged, the intramedullary pressure is not increased much during the insertion process, and the complications of fat embolism are few; at the same time, the elastic fixation of the two needles is strong and can be tight Embedded in the medullary cavity, effectively preventing the rotation of the fracture, so it is more common in clinical practice, especially the plum blossom shape is more commonly used. Round needles are only used for short tubular bones such as metacarpal and humerus. Solid intramedullary nails have been abandoned due to severe bone marrow destruction. Treatment of diseases: humeral fractures, ulnar and radial fractures Indication 1. The middle part of the long bone, especially at the junction of the upper and middle 1/3 (the middle part of the tibia) is a horizontal or short oblique fold. The fracture has a small piece of smashed fold and a butterfly fold, but it can be applied. The wire is fixed. 2. Long bones and multiple bone fractures, or multiple multiple fractures of the body, difficult to fix by external fixation, the fracture site is suitable for intramedullary nail fixation. 3. The site suitable for fracture malunion (or non-healing), need to open the reduction. 4. Suitable pathological fractures. Contraindications 1. Children with long bone fractures, although combined with the above indications, should not be applied to avoid damage to the epiphysis; 2. Elderly patients with osteoporosis, thin cortex, large medullary cavity, the diameter of the femoral canal can reach 15 mm (the youngest is only 6 ~ 7 mm), the curvature of the anterior and posterior femur is increased, the intramedullary needle is not fixed, Complications should be used with caution. 3. Severely contaminated open fractures should not be fixed with intramedullary nails. Once infected, it will be difficult to control, and should be considered after soft tissue healing. Preoperative preparation 1. Selection of intramedullary needle: It is necessary to select an intramedullary needle of appropriate thickness and length to exert sufficient fixation. The length of the intramedullary nail can be shortened by 4 to 6 cm according to the length measured by the contralateral bone, and the width can be about 1 mm smaller than the diameter of the narrowest part of the medullary cavity shown by the x-ray (2 mm smaller than the femur). The correct way is to fix the intramedullary needle of known width to the same plane of the injured bone or the healthy side of the bone. However, these methods are only for rough estimation, and it is still advisable to prepare a few intramedullary needles for intraoperative selection. Intraoperative injection of the intramedullary nail can be directly inserted into the stenosis of the medullary cavity, but in case of resistance, it is inevitable to insert it strongly, so as to avoid bone fracture or difficulty in pulling out. Intramedullary needles of a diameter or a little wider than the diameter of the segment should generally be selected to achieve maximum cross-sectional elastic fixation. 2. The surgeon should fully estimate the difficulties and complications that may occur during the operation, and prepare the instruments to be treated (such as hacksaws, multiple medullary cavity expanders, wires, etc.). Surgical procedure Closed intramedullary internal fixation: the fracture end is not revealed. After the fracture is closed and closed, a small incision is made only at the needle insertion end of the long bone. Under the guidance of the TV x-ray machine or the film, the intramedullary nail is used. Into the medullary cavity, through the fracture to the required depth. The advantage of this method is that it can avoid cutting the fracture end, reduce the chance of infection and local blood supply damage; the disadvantage is that the equipment requirements are high, the technology is more complicated, the selection of the intramedullary needle is not suitable, and the complications are more. Open intramedullary internal fixation: the fracture end is revealed, and the needle is placed under direct vision. This method is safer and easier to use, and is more clinically used. Open intramedullary internal fixation can be divided into two types: the antegrade method and the retrograde method: the antegrade method is to insert the needle from the end of the bone once, through the fracture, into the other fracture segment, and the fracture end is less exposed. The damage is small, but the direction of the needle is difficult to grasp, and it is generally used for fractures with a shallow position and easy to grasp in the direction of the needle (such as the ulna, the tibia and the tibia). The retrograde method is to retrograde the intramedullary nail from the proximal end of the fracture to the end of the bone. After the reduction, the anterograde needle is inserted into the distal segment of the fracture. The technique is simpler and safer than the antegrade method, and is clinically useful. However, the fracture end of this method has a large exposure range, the incision is long, the periosteum is widely peeled off, and the blood transfusion is heavier, and it is often used for fractures with many surrounding muscles and difficult to grasp in the direction of the needle. (a) antegrade method (taking femur fracture as an example) 1. Incision and exposure of the fracture end: the incision does not need to be too long, and the exposed range of the fracture can hold the fracture end of the fracture. 2. Needle insertion point: The needles of each bone are different. The femur is the inner side of the greater trochanter, the humerus is the trochanter, the ulna is the apex of the olecranon, the humerus is the distal end, and the tibia is the large nodule [Fig. 3]. Make a small longitudinal incision on the skin at the needle insertion, separate the soft tissue, peel the periosteum to reveal the cortical bone of the predetermined needle point, and position the needle point on the axis of the x-ray film and the medullary cavity, according to the intramedullary nail. The shape is chiseled off part of the cortical bone to avoid splitting fractures when the needle is inserted. 3. Enlarge the medullary cavity: the fracture or narrowing of the medullary cavity at the fracture end, such as old fractures and non-union, or the diameter of the medullary stenosis is too small, irregular protrusions in the medullary cavity, and fractures in the stenosis are required to be used. A medullary cavity expander with an equal diameter or a diameter of 0.5 mm is drilled or drilled to enlarge the medullary cavity, and a thicker intramedullary needle is used to enhance the fixation effect. 4. Needle insertion: Select a suitable intramedullary needle and slowly use the bone hammer to move from the needle point of the greater trochanter of the femur to the medullary cavity. In order to avoid the wrong direction of the needle, a guide needle can be placed in the medullary cavity at the proximal end of the fracture to indicate the direction of the needle, and the needle is taken out in the correct direction. When the intramedullary needle is exposed through the marrow cavity at the proximal end of the fracture, the fracture is restored under direct vision, and the person is kept in alignment and alignment (or fixed with a fracture fixator), and the surgeon continues to hammer the needle into the distal segment of the fracture. The appropriate depth. When the intramedullary needle tail enters the skin incision, the intramedullary needle driver is placed on the end of the intramedullary needle to slam. The depth of insertion of the intramedullary needle is suitable for the upper edge of the humerus. The outer part of the intramedullary needle is 2.5 mm. The extraction hole should be left outside the bone for the purpose of needle extraction after fracture healing. 5. Treatment of the fracture end: After the intramedullary nail enters, the reduction and abnormal activity of the fracture end should be checked. If there is a crack, the bone end should be buckled to make the fractures close together. If there is abnormal activity, the width of the selected intramedullary needle is insufficient, and the thicker intramedullary nail should be removed. For delayed or old fractures, bone grafts should be performed at the same time to promote bone healing. The slit is finally layered. (2) Retrograde method (taking femur fracture as an example) After incision reveals the fracture end, the intramedullary needle tail is driven retrogradely from the proximal medullary cavity of the fracture to the greater trochanter of the femur, where a small incision is made in the local skin to reveal the cortical bone. Then remove some of the bone, continue to reverse the needle, and take the intramedullary needle from the rotor until the tip of the needle is flush with the proximal end of the fracture. Then, the fracture end was restored, and the needle was hammered into the distal segment of the fracture by the antegrade method. complication 1. Intramedullary needle incarceration: mostly due to the intramedullary needle is too thick, stuck in the stenosis of the medullary cavity, or the direction of the needle is wrong, inserted into the cortical bone. During surgery, you should pay attention to the size of the intramedullary needle and grasp the direction of the needle. Once it happens, correct it in time to avoid a dilemma. 2. Splitting fracture: If the needle is not removed, some of the bone will be reinforced, or the intramedullary needle will not be corrected in time. Instead, the needle will be forced to cause a split fracture. The treatment method must be determined according to the fracture condition. Or pull out the re-insertion, add wire fixation, or use other internal fixation. 3. Intramedullary nails are bent and broken: mostly due to the intramedullary needle being too thin and not strong enough; it can also be caused by premature, excessive load or damage. The method of prevention is to choose a suitable intramedullary nail, do not prematurely carry weight after surgery, and pay attention to protection during activities. After the intramedullary nail is bent, the method can be straightened under anesthesia and external fixation can be added. The breakage needs to be removed and replaced. When removed, the proximal intramedullary nail can be pulled out with an extractor. In the distal segment of the bone marrow, a part of the bone should be cut at the fracture end. The intramedullary needle is pulled with a pointed forceps and then re-introduced into the intramedullary nail. Bone bone was implanted at the bone defect and fixed with steel wire. 4. Infection: Emphasis must be placed on strict adherence to aseptic technique. For open fractures of more than 8 to 12 hours, the wound should be treated first, and the internal fixation should be performed after the soft tissue is healed. Once the infection occurs after surgery, there is no need to rush to pull out the intramedullary nail, first treat it according to acute osteomyelitis. After some osteophytes at the fracture end, the intramedullary nail is removed and osteomyelitis is performed. 5. Fat embolism: a small amount of fat granules enter the blood circulation during fracture, and the emergency surgery increases the amount of entry, resulting in the formation of embolism, which is a rare complication of intramedullary needle internal fixation. Therefore, the decision to perform intramedullary nail fixation, no need for emergency surgery, should be carried out without skin traction for several days; intraoperative needle insertion speed should be slow, and the use of plum-shaped, v-shaped hollow intramedullary nail, embolism symptoms are rare occur.

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