基于三维有限元模型分析鼻部软组织形变并优化挛缩鼻畸形机械牵拉治疗方案

Analysis of nasal soft tissue deformation and optimization of mechanical stretch therapy for nasal contracture deformity based on three-dimensional finite element model

目的建立鼻部三维有限元模型,模拟分析不同着力点、牵拉方向及模式产生的鼻部组织形变,为物理牵拉治疗的有效性提供理论依据,指导临床选择更高效的物理牵拉治疗方法。方法获取1名29岁男性健康志愿者(无明显鼻部畸形)于2022年5月在北京大学第三医院进行鼻部CT扫描的数据,分离出外鼻影像,采用ANSYS Workbench 19.2软件建立鼻部三维有限元模型,选取鼻尖、鼻小柱2个着力点和平行向前、前下方30°、前下方60°3个施力方向,比较不同牵拉条件在皮肤、衬里、软骨3个组织层面和鼻尖、鼻根、鼻小柱中点和鼻基底4个解剖标志产生的形变。在相同牵拉条件下,比较10 min持续牵拉和10次1 min脉冲式牵拉产生的形变。比较24 h周期内单次1 h和间歇6次10 min 2种牵拉模式产生的形变。结果所有牵拉条件均可使鼻部模型产生形变,其中向前下方60°牵拉取得的鼻部组织最大形变值(4.6329 mm)大于其他牵拉条件(0.8250~3.1050 mm),形变最大值位于模型皮肤层的鼻根附近。10 min持续牵拉获得的形变值(0.1766 mm)略大于10次1 min的脉冲式牵拉(0.1765 mm)。24 h内,6次间歇牵拉模式的最终形变(0.0190 mm)大于单次牵拉模式(0.0043 mm)。结论物理牵拉可使鼻部皮肤软组织产生有效形变,效率最高的操作方式为短时间持续夹捏鼻尖并平行于鼻背向下施加拉力,间隔数小时重复。

ObjectiveTo establish a three-dimensional finite element model of the nose,simulate and analyze the deformation of nasal tissue caused by different focal points,traction directions,and modes,provide the theoretical basis for the effectiveness of physical traction therapy,and guide the clinical selection of more efficient physical traction therapy methods.MethodsA finite element model of the nose was established by ANSYS Workbench 19.2 software based on image data obtained from CT scans of a 29-year-old male volunteer with normal nasal appearance in Peking University Third Hospital.Two focal points,the nasal tip,and the nasal columella,were selected,and three force directions,parallel to the forward,forward and down 30°,forward and down 60°,were applied.The deformation caused by different traction conditions on the skin,lining,and soft bone parts,as well as the four anatomical landmarks of the nasal tip,nasal root,the midpoint of the nasal columella,and the nasal base,were compared.The deformation produced by 10 minutes of continuous pulling and 10 times 1-minute pulse pulling were compared under the same pulling conditions.The deformations generated by two types of pulling modes within a 24-hour cycle:a single 1-hour cycle and 6 intermittent 10-minute cycles,were compared.ResultsAll traction conditions resulted in deformation of the nasal model,with the maximum deformation of the nasal tissue obtained by pulling forward and downward at 60°(4.6329 mm)which was greater than other traction conditions(0.8250-3.1050 mm).The maximum deformation value was located near the nasion of the model’s skin layer.The deformation obtained by 10 minutes of continuous pulling(0.1766 mm)was slightly greater than that obtained by 10 times of 1-minute pulse pulling(0.1765 mm).Within 24 hours,the final deformation of multiple intermittent pulling modes(0.0190 mm)was greater than that of a single pulling mode(0.0043 mm).ConclusionPhysical traction can effectively deform the skin and soft tissue of the nose,and the most efficient operation is to continuously pinch the tip of the nose for a short period and apply tension parallel to the back of the nose downwards,repeating every a few hours.