黏小管成形术中缝合线扩张小梁网过程的有限元分析与实验研究

Finite Element Analysis and Experimental Investigation of the Dilation Process of Trabecular Meshwork by Suture for Canaloplasty

黏小管成形术是治疗青光眼较为安全有效的新型手术方式,医生通过向患者施莱姆氏管(Schlemm’s canal,SC)中递送缝合线一周并张紧的方法,使患者小梁网(trabecular meshwork,TM)和施莱姆氏管处于扩张状态,恢复房水自然流出通路从而降低眼内压。然而,缝合线张紧力是组织扩张的直接因素,过大会导致组织损伤,医生往往通过经验或出血进行扩张程度判断。为了研究缝合线上张紧力与组织扩张的关系,采用有限元方法建立了包含巩膜、施莱姆氏管、小梁网和缝合线的数值计算模型,进行了黏小管成形术的仿真分析,并开展了猪眼球实验验证。结果表明:施莱姆氏管和小梁网由松弛变形至术后扩张状态的过程中,扩张宽度随着缝合线拉力的增加而逐渐增大,仿真中拉力为43.5~57.3 mN时,扩张宽度为300~390μm;实验中拉力在34.1~66.6 mN范围时,扩张宽度为297.8~404.6μm,实验结果与仿真结果呈现相同趋势。所提方法可以用于实时预测术中施莱姆氏管和小梁网的扩张程度,辅助医生进行决策,提升手术精准性。

Canaloplasty is a safer,effective and novel surgical method for glaucoma.A suture is delivered 360°around the Schlemm’s canal(SC)and tightened by doctor to keep the patient’s SC and trabecular meshwork(TM)in a state of dilation,which can restore the natural outflow of aqueous humor to reduce intraocular pressure.However,it will cause tissue damage,if the tension,a direct factor in the dilation of the tissue,is too much.Doctors often judge the extent of dilation based on experience or hyphema.To investigate the relationship between the tension of suture and tissue dilation,a numerical calculation model including sclera,SC,TM and suture was established by finite element method.The simulation analysis for canaloplasty and porcine eye verification experiment were carried out.The results show that in the process of SC and TM expanding from relaxation to postoperative expansion state,the dilation width of SC and TM gradually increase with the increase of suture tension.The expansion width gradually increases with the increase of suture tension.When the tension in the simulation is 43.5~57.3 mN,the expansion width is 300~390μm.In the experiment,when the tensile force is in the range of 34.1~66.6 mN,the expansion width is 297.8~404.6μm.Experiment and simulation results show the same trend.The proposed method can be used to predict the dilation of SC and TM in real time,assist doctors in decision-making,and improve the accuracy of surgery.