獸醫專業學院: 臨床動物醫學研究所指導教授: 蘇璧伶; 葉力森何之遠Ho, Chi-YuanChi-YuanHo2017-03-062018-07-092017-03-062018-07-092015http://ntur.lib.ntu.edu.tw//handle/246246/277096犬之肱骨骨髁骨折為犬常見骨折之一。為保存肘關節之功能性，常建議以手術方式進行復位及骨折固定，以利骨折修復過程中發生直接性骨折癒合。經骨髁之壓力螺釘提供了固定骨髁骨折同時提供斷面間壓力的優點，進而達到直接性骨折癒合之目的；然而，其缺點包括骨質損失較多、術野暴露範圍較大及造成較多的周邊軟組織傷害，皆不利於骨折修復。過去曾有學者提出在長骨骨折固定上應用預加壓力之方法，先以預加壓力裝置在斷面間施壓，再以螺釘固定並維持先前施予的預加壓力。本研究目的為將預加壓力的概念應用於骨髁骨折固定，比較傳統壓力螺釘和預加壓力之位置螺釘產生與維持骨折斷面間壓力的效果，以及進行二者應用於犬隻骨髁骨折時之生物力學測試。 第一階段的研究中，將豬肋骨中段骨幹處橫切分為兩段，隨機分配一段為壓力螺釘組，另一段為預加壓力之位置螺釘組，各製造出長2 cm的半圓柱狀游離斷片，做為骨折模型。於斷面間放置薄膜型壓力感測器，分別植入壓力螺釘與預加壓力之位置螺釘。以不同扭力植入螺釘，進行三部分實驗，第一部份：7對樣本以0.2 Nm植入壓力螺釘及預加壓力之位置螺釘，第二部份：5對樣本以0.4 Nm植入壓力螺釘及預加壓力之位置螺釘，第三部份：10對樣本以0.2 Nm植入壓力螺釘、0.4 Nm植入預加壓力位置螺釘。將由壓力感測器取得的數據以Mann-Whitney test進行分析，p值<0.05表示有顯著差異。第二階段的研究則利用犬隻大體的雙側肱骨樣本製造出骨髁骨折，左右側肱骨分別植入壓力螺釘及預加壓力之位置螺釘後，以拉伸機機械試驗比較受力與斷片位移情形。 第一階段研究中的第一部份實驗結果顯示，以0.2 Nm植入壓力螺釘所產生斷面間之力量及壓力為2.71±1.05 Kg及1.48±0.62 MPa，預加壓力之位置螺釘則為2.69±1.22 kg及1.55±0.71 MPa，兩組間斷面間力量及壓力皆無顯著差異。第二部份實驗中，以0.4 Nm植入螺釘，所有壓力螺釘皆發生滑牙，導致斷面間力量及壓力為0±0 kg及0±0 MPa，預加壓力之定位螺釘力量與壓力分別為3.16±0.82 kg與1.83±0.47 MPa，兩組間在斷面間力量（p&lt;0.01）及壓力（p&lt;0.01）的比較上皆有顯著差異。第三部份實驗中，以0.2 Nm植入壓力螺釘，產生之斷面間力量與壓力分別為1.80±0.91 kg及1.04±0.53 MPa，而以0.4 Nm植入預加壓力之位置螺釘產生之斷面間力量與壓力分別為3.07±1.25 kg及1.77±0.74 MPa，兩組間的斷面間力量及壓力皆有顯著差異（p&lt;0.03）。第四部份的實驗，比較未使用預加壓力之壓力螺釘與移除持骨鉗之後的預加壓力合併壓力螺釘，給予預加壓力之壓力螺釘的斷面間力量和壓力分別為3.01±1.06 kg及1.74±0.61 MPa，未使用預加壓力之壓力螺釘則為3.88±1.17 kg及2.24±0.67 MPa，兩者在統計上並無顯著差異（斷面間力量：p=o.75；斷面間壓力：p=0.75）。進一步分析後，移除持骨鉗前後之斷面間力量各為6.06±1.72 kg和3.01±1.06 kg（p&lt;0.01），斷面間壓力則為3.50±0.99 MPa和1.74±0.61 MPa（p&lt;0.01），移除持骨鉗之後斷面間力量和壓力皆顯著下降。 第二階段研究為前期試驗，共以兩組犬隻大體肱骨進行實驗，體重上分別為7 kg及22 kg。比較固定後X光片，使用預加壓力之位置螺釘在X光片下呈現較小的斷面間隙。而在進行拉伸機生物力學測試後，比較植入物失敗前最大位移下7 kg犬樣本之壓力螺釘及預加壓力之位置螺釘結果各為7.96 mm及4.11 mm、60%體重時則各為1.66 mm及0.68 mm而130%體重時則為2.44 mm及0.68 mm；而22 kg犬樣本之前述結果各為17.54 mm及7.97 mm、5.74 mm及1.37 mm、9.64 mm及3.97 mm；兩組之預加壓力之位置螺釘皆呈現較小位移。 依據上述結果，預加壓力之位置螺釘相比於壓力螺釘可以提供較大的斷面間壓力及力量、較大扭力耐受性、較小滑牙機會及較少斷面間位移等優點。但其於犬隻肱骨骨髁骨折的應用，仍需以更多時體樣本進行生物力學測試，以及活體病患臨床應用，以證實目前觀察結果之正確性。Humeral condylar fracture is a common fracture in canine. In order to preserve the joint function, surgical management for reduction and steady fixation via transcondylar lag screw is recommended to achieve the direct bone healing. The advantage of lag screws is fixing the fracture and generating a compression effect concurrently. However, disadvantages of lag screws, such as increased loss of bone tissue, larger area for surgical approach, and creating more damage to the surrounding soft tissues, may delay the bone healing. In the literature, preloading compression effect has been proposed and applied in the fracture fixation for long bone. Prior to installing screws, a preloading compression device is applied to provide the interfragmentary compression effect, which would be maintained after screw installation and device removal. The aims of the study is to evaluate the inter-fragmentary compression effect and biomechanical strength between preloading positional screws (PPS) and traditional lag screws (LS) in fracture fixation. In the first stage of the study, fresh porcine rib was used to create the bone fracture model. The rib was transversely sawed at the midpoint, and randomly one of the paired segments was assigned to the LS group and the other to the PPS group. In each segment, a semi-cylindrical-shaped, 2-cm length, free bone fragment was created. A wireless film compressive sensor was placed in the fracture gap to record the real-time inter-fragmentary mechanical force, followed by screw installation. Three experiments were carried out: a) 0.2 Nm toque was applied to install screws in both groups in 7 paired samples, b) 0.4 Nm toque was applied to install screws in both groups in 5 paired samples, and c) 0.2 Nm toque was applied in LS group and 0.4 Nm torque in PPS group in 10 paired samples. Data from the film compressive sensor were analyzed by Mann-Whitney test. P value of less than 0.05 was considered statistically significant. In the second stage of the study, condylar fracture was created in paired humerus from canine cadaver and fixed by a LS or PPS. Biomechanical testing and radiographic evaluation was performed. When applied 0.2 Nm torque, no significant difference was detected between two groups regarding the interfragmentary force and pressure. When applied 0.4 Nm torque, all LS failed due to stripped-thread so did not generate interfragmentary force and pressure. In the PSS group, the interfragmentary force and pressure was 3.16±0.82 kg and 1.83±0.47 MPa respectively. There were significant differences between two groups regarding both the interfragmentary force and pressure (p&lt;0.01). In the third experiment, the interfragmentary force and pressure were 1.80±0.91 kg and 1.04±0.53 MPa in the LS group under 0.2 Nm torque, 3.07±1.25 kg and 1.77±0.74 MPa in the PPS group under 0.4 Nm torque. Significant differences were detected between two groups regarding the interfragmentary force and pressure (p&lt;0.05). When comparing the interfragmentary force and pressure between conventional unpreloaded lag screws and preloaded lag screws after the removal of the preloading device, the results showed no significant difference between two groups no matter in force (force: 3.01±1.06 kg verse 3.88±1.17 kg, p=0.75; pressure: 1.74±0.61 MPa verse 2.24±0.67 MPa, p=0.75). However, when comparing the interfragmentary force and pressure before and after the removal of the preloading device in the group of preloaded lag screws, significant difference was detected in force (6.06±1.72 kg verse 3.01±1.06 kg, p&lt;0.01) and pressure (3.50±0.99 MPa verse 1.74±0.61 MPa, p&lt;0.01). There was a pilot study in the second stage of the study, two pairs of humerus from a 7-kg and a 22-kg canine cadaver were examined. Radiographic evaluation revealed less interfragmentary gap in the PPS group. In addition, the displacements of LS and PPS were 7.96 mm and 4.11 mm respectively in 7-kg dog model before implant failure. The 60% of the body weight were 1.66 mm and 0.68 mm, and 130% of the body weight were 2.44 mm and 0.68 mm. In 22-kg dog model, the displacements were 17.54 mm and 7.97 before implant failure. The 60% of the body weight were 5.74 mm and 1.37 mm, and 130% of the body weight were 9.64 mm and 3.97 mm. Less device displacement was also noted in the PPS group under the maximal force prior to implant failure and the force equal to 60% and 130% of the body weight. In conclusion, compared with traditional lag screws, preloading positional screw provides larger interfragmentary force and pressure, tolerates larger toque when installing, has lower chance of thread stripping, and creates less interfragmentary displacement during the biomechanical testing. However, larger sample size for the radiographic evaluation and biomechanical testing is needed to more dogs cadaver models further confirm the current observation and needed living patient in clinical application outcome.7392160 bytesapplication/pdf論文公開時間: 2020/8/20論文使用權限: 同意有償授權(權利金給回饋學校)預加壓力位置螺釘壓力螺釘骨髁骨折preloading compression effectpositional screwlag screwcondylar fracturethesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/277096/1/ntu-104-R02643013-1.pdf