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Surgical procedure for iMAP.



Consider the placement of the iMAP. In the case of internal fixation with an intramedullary nail, it may spread along the intramedullary nail and away from the fracture. In addition, since there is no space for inserting the pin in the mid shaft, there is some space at the metaphysis. In the case of plate or external fixation, aim about 5 cm away from the fracture site. In the case of chronic osteomyelitis, if the inflammation has spread along the medullary canal by diagnostic imaging, place the device at the border of inflammation area.



The tip of the iMAP pin has a root diameter of 2.4mm, so pre-drill it with a 2.4mm K-wire. Basically, it is better to fix by penetrating the bone cortex on the contralateral side, but it may be difficult depending on each case. Since there is a screw at the tip, a certain degree of fixation can be obtained even if it is kept in the medulla. When the patient rests in the supine position with slightly external rotate the lower extremity and the pin is standing vertically, it is less likely to come loose due to contact with the surroundings.



Insert iMAP with a dedicated driver. Carefully insert the pin so that it does not move in the insertion direction. Excessive play may cause leakage from the insertion site. Insertion ends just past the contralateral cortex. There is an outflow hole 10 mm from the tip. If the pin is attached to a power tool and inserted, it may break at the hole at the tip, so manual insertion is preferable.



A connector that can be connected to the tube is installed in the tail. If infection is established, bone marrow fluid is collected and submitted for culture. Next, saline is manually injected using another syringe. If smooth press-fitting is not possible, the bone hole may be clogged with bone debris, or the bone hole may be covered with cortical bone, so fine adjustment is performed. Confirm that intramedullary injection is possible from the iMAP pin. In some cases, a contrast agent may also be used.


Flow test

Next, it is confirmed that the saline pressurized into the intramedullary is flowed out to the fracture site and the lesion site (flow test). If there is a distance from the Pin to the fracture site, or if the intramedullary hardening due to chronic inflammation, the injected fluid may not reach. Adjust the K-wire so that the injected fluid can flow out by perforating the intramedullary from the fracture or perforating from the cortex to the medullary cavity.



A drainage tube is placed at the fracture site to allow aspiration of fluid that has flowed out. Confirm that the injected fluid flows out of the fracture and is quickly absorbed from the suction tube. Essentially, wound irrigation should be performed using this route, which flushes out from the inside to outside. Thorough the repeated irrigation during wound closure, it will prevent the tube from clogging with thrombus.


Final check

チューブに何を用いるかはiSAPのところを参照する。ただ、iMAP pinから抗菌薬をinfusionするだけでは、血中濃度が過度に上昇するため、必ずoutflowを作成して循環する=perfusionすることを確認して手術を終了する。

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