目的:对于严重的下颌骨骨折,快速成型和组装现代外固定器仍然是一个挑战,尤其是在紧急情况下。我们设计了一种新型的外固定器,该固定器结合了万向节,可为下颌骨粉碎性骨折提供稳定。本研究旨在通过体外生物力学测试和动物实验证实这种新型外固定器的功效。
方法:使用6只具有下颌骨缺损的新鲜犬进行体外生物力学测试,以模拟严重的粉碎性骨折。用新型外固定器稳定三个下颌骨,用2.5mm重建板固定其他下颌骨。所有固定的下颌骨在牙齿的前部区域承受350N的载荷,在未受影响的一侧的第一磨牙承受550N的载荷。根据最大位移和载荷-位移曲线的斜率评估稳定性。在动物实验中,将9只患有下颌骨粉碎性骨折的比格犬分为3组,用新型外固定架治疗,重建板,和牙弓棒,分别。一般的观察,动物体重的变化,记录并比较3组的手术时间。以0天的不同间隔(手术后立即)进行CT扫描,3天,7天,14天,21天,和28天分析犬下颌骨特征点的位移和28天骨折愈合情况。通过方差分析和Bonferroni检验的双向分析来评估统计学意义。使用GraphPadPrism10.1.0(GraphPadInc,美国)。
结果:生物力学测试结果表明,外固定组和内固定组之间在两种载荷模式下的最大位移(p=0.496,0.079)和载荷位移曲线斜率(p=0.374,0.349)方面没有统计学上的显着差异。动物实验数据显示,外固定组和内固定组之间的特征点存在微小位移,无统计学差异。而足弓杆组的稳定性较差。CT分析显示内固定组骨折愈合最好,然后在固定后28天进行外固定和牙弓裸露。外固定组固定时间(25.67±3.79)min短于内固定(70.67±4.51)min,p<0.001)和足弓裸露((42.00±3.00)min,p=0.046)。
结论:本研究的结论强调了这种新型外固定器快速治疗下颌骨骨折的有效性和可靠性,在紧急救援的背景下,为下颌骨粉碎性骨折的初步稳定提供了一个可行的选择。
OBJECTIVE: Shaping and assembling contemporary external fixators rapidly for the severe mandibular fractures remains a challenge, especially in emergency circumstance. We designed a novel external fixator that incorporates universal joints to provide the stabilization for mandibular comminuted fractures. This study aims to confirm the efficacy of this novel external fixator through biomechanical tests in vitro and animal experiments.
METHODS: In vitro biomechanical tests were conducted using 6 fresh canine with mandibular defect to simulate critical comminuted fractures. Three mandibles were stabilized by the novel external fixator and other mandibles were fixed by 2.5 mm reconstruction plates. All fixed mandibles were subjected to loads of 350 N on the anterior regions of teeth and 550 N on the first molar of the unaffected side. The stability was evaluated based on the maximum displacement and the slope of the load-displacement curve. In animal experiments, 9 beagles with comminuted mandibular fractures were divided into 3 groups, which were treated with novel external fixation, reconstruction plate, and dental arch bar, respectively. The general observation, the changes in animals\' weight, and the surgical duration were recorded and compared among 3 groups. The CT scans were performed at various intervals of 0 day (immediately after the surgery), 3 days, 7 days, 14 days, 21 days, and 28 days to analyze the displacement of feature points on the canine mandible and situation of fracture healing at 28 days. The statistical significance was assessed by the two-way analysis of variance test followed by the Bonferroni test, enabling multiple comparisons for all tests using GraphPad Prism10.1.0 (GraphPad Inc, USA).
RESULTS: The outcomes of the biomechanical tests indicated that no statistically significant differences were found in terms of the maximum displacement (p = 0.496, 0.079) and the slope of load displacement curves (p = 0.374, 0.349) under 2 load modes between the external and internal fixation groups. The animal experiment data showed that there were minor displacements of feature points between the external and internal fixation groups without statistic difference, while the arch bar group demonstrated inferior stability. The CT analysis revealed that the best fracture healing happened in the internal fixation group, followed by the external fixation and arch baring at 28 days after fixation. The external fixation group had the shortest fixation duration (25.67 ± 3.79) min compared to internal fixation ((70.67 ± 4.51) min, p < 0.001) and arch baring ((42.00 ± 3.00) min, p = 0.046).
CONCLUSIONS: The conclusion of this study highlighted the efficacy and reliability of this novel external fixator in managing mandibular fractures rapidly, offering a viable option for the initial stabilization of comminuted mandibular fractures in the setting of emergency rescue.