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Gradual distraction with an external fixator is a widely used treatment for severe postburn ankle contracture (SPAC). However, application of external fixators is complex, and conventional two-dimensional (2D) imaging-based surgical planning is not particularly helpful due to a lack of spatial geometry. The purpose of this study was to evaluate the surgical planning process for this procedure with patient-specific three-dimension-printed models (3DPMs). In this study, patients coming from two centers were divided into two cohorts (3DPM group vs. control group) depending on whether a 3DPM was used for preoperative surgical planning. Operation duration, improvement in metatarsal-tibial angle (MTA), range of motion (ROM), the American Orthopedic Foot and Ankle Society (AOFAS) scores, complications, and patient-reported satisfaction were compared between two groups. The 3DPM group had significantly shorter operation duration than the control group ((2.0±0.3) h vs. (3.2±0.3) h,
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Objective:To investigate the safety and feasibility of the occipital condyle screw and evaluate the safepath parameters for the occipital condyle screw.Methods:Data of 64 patients with upper cervical computed tomographic angiograms from September 2016 to September 2018 were retrospectively collected. Excluded occipito-cervical injury, tumor, and vertebral artery course variation. Mimics software was used to reconstruct the occiput, atlas and vertebral artery. Three candidate entry points were placed for each occipital condyle, the midpoint of posterior of occipital condyle as middle entry point, and the medial and lateral entry points were located 3 mm medial and lateral to the middle entry point. The vertebral artery-occipital bone distance (VOD) of each entry point were measured on sagittal plane, and the minimum feasible value was determined to be 4mm. After that 3.5 mm diameter virtual screw was inserted into each candidate entry point with VOD>4 mm, each screw with maximum and minimum cranial angulation was combined with appropriate medial angulation to get the maximum screw length. Then, the screw placement parameters were measured by 3-Matic, and the safe range of cranial angulation and the success rate of screw placement were calculated.Results:The VOD of medial and middle entry point were 8.07±2.13 mm and 7.70±2.19 mm respectively, and the feasibility rate of screw placement of those entry point were 97.7% and 96.1%, respectively. There were significant differences inVOD and feasibility rate of screw placement between medial and middle entry point. The VOD of lateral entry point was 5.63±1.66 mm, and the feasibility rate was only 78.9%, which was significantly lower than that of medial and middle entry point. The lateral entry point could obtain a larger medial angulation, which was supplemented by a longer screw length. The medial angulation and length of screw gradually decreased with the inward movement of the entry point. There were significant differences in medial angulation and screw length among groups. The safe range of cranial angulation of medial, middle and lateral entry points were 8.17°±2.55°, 12.58°±4.23° and 12.09°±3.83°, respectively, and the difference were statistically significant. Among the screw entry point that could accommodate screw fixation, the maximum screw placement success rate can be obtained by adding 5° cranial angulation to the lateral and middle entry point, which were 98.02% and 98.37%, respectively,while 100% success rate of screw placement could be obtained at the medial entry point at 3° cranial angulation.Conclusion:In the selection of the entry point in the horizontal direction, middle and medial entry points have higher success rate of screw placement and wider safe range of cranial angulation because of less affection of horizontal segment of the vertebral artery. However, the screw length of medial entry point is much shorter than middle and lateral entry point. As a result, the middle entry point may be an optimal entry point for the occipital condyle screw.
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Objective To explore the application of UW solution in the replantation of the rat limb,and to explore a simple method for the ideal preservation of the amputated limbs.Methods From September,2017 to Janurary,2018,one hundred and twenty healthy adult male SD rats,weight 320-350 g,were randomly divided into 8 groups:A,B,C,D,E,F,G,H group.The isolated limbs of the control group A,C,E,G were cryopreserved in refrigerator at 4 ℃,while those of the experiment group B,D,F,H were preserved under the same condition after being perfused with UW solution.All the severed limbs were replanted back to the rats after different time length of cry opreservation:A,B 12 hours,C,D 20 hours,E,F 28 hours and G,H 36 hours.During the operations the femoral artery and venous patency were detected immediately after anastomosis.And after the operations the survival rates of limb replantation were observed.On the third day after the limb replantation,the tibial posterior muscle tissue was examined for pathology.The cell areas in pathological photographs were compared with Image analysis software Image-pro Plus 6.0 and the ultra structural changes of skeletal muscle tissue were observed.Results The femoral artery and venous patency in experiment group A,C,E and control group B,D,F were all 100 percent.However,in the group G,H the severed limb vessels changed obviously,the patency dropped markedly and the survival rates of limb replantation turned out to be 0.The experiment groups perfused with UW solutions,had relatively higher survival rates compared with the control groups (12 h:93.33％ vs.53.33％,20 h:80.00％ vs.40.00％,28 h:53.33％ vs.13.33％) and the skeletal muscles edema was lighter than that of the control group,with a larger proportion of cell areas(12 h:69.49±8.57 vs.44.75±6.34,20 h:56.34±7.73 vs.36.69±5.74,28 h:45.76±8.23 vs.31.49±7.72).There was a significantly difference (P＜0.05).Electron microscope observation showed that the experiment group bore a lighter damage of myofibril,interstitial tissue and mitochondria compared with the control group.Conclusion The combination of UW solution and cryopreservation of organs is an ideal and proper way to preserve the amputation limb,to extend the time limit for replantation,and to achieve a better recovery effect of postoperative limb function.Besides,UW solution is easy to be promoted in the treatment of isolated limb in clinical work.