Experimental Study Of A Novel Internal Trabeculectomy Device

BackgroundGlaucoma is a common cause of blindness.As the disease progresses,it can cause progressive and irreversible optic neuropathy,leading to different degrees of vision loss and visual field defect.If no timely and effective intervention measures are taken,it will even develop into blindness,which seriously affects the quality of life of patients.The primary age of onset of the disease is between 40 and 80 years,and the incidence of glaucoma is increasing as the aging population increases.There are many factors affecting the onset of glaucoma,such as age,season,gender,elevated intraocular pressure,lifestyle,family history,high myopia,diabetes and cardiovascular disease.Among them,pathological elevation of intra-ocular pressure is a key determinant of disease progression and the only modifiable risk factor identified so far.The higher the intraocular pressure and the longer it lasts,the more likely it is to cause optic neu-ropathy.Therefore,the key of current glaucoma treatment is to reduce the degree of optic nerve damage by reducing intraocular pressure,so as to achieve the purpose of preserving visual function.The regulation of intraocular pressure is closely related to aqueous humor circulation.Therefore,we can regulate the level of intraocular pressure by adjusting the function of aqueous humor circulation.At present,increasing aqueous humor discharge or reducing aqueous humor production by means of medication,laser,and operation is the main means to reduce intraocular pressure.In recent years,minimally invasive glaucoma surgery,an emerging surgical method,as a safe and effective treatment means,has been more and more applied in the treatment of patients with mild and moderate glaucoma.In the early stage,our team combined the advantages of some minimally invasive glaucoma surgical devices already on the market,and developed a new minimally invasive glaucoma surgical device--a new minimally invasive internal trabeculectomy device.However,the feasibility of this device is still uncertain,and further experimental research is needed.ObjectivePreclinical experimental studies should be conducted on animal models to evaluate the feasibility of the new minimally invasive internal trabecular resection device before its clinical application.In this study,we intend to use an isolated porcine eye perfusion model to conduct relevant experiments.To compare the effects of the new minimally invasive internal trabeculectomy device with a clinically used trabecular resection device--kahook dual blade.In terms of intraocular pressure and external drainage rate,in order to evaluate the feasibility of this device as an alternative treatment for glaucoma in the clinic.Research methods1.To explore the influence of a new minimally invasive internal trabeculectomy device on intraocular pressureEight fresh isolated porcine eyes were taken and divided into left and right eyes according to eyelids and appendage,and divided into two groups: the left eye was the new minimally invasive internal trabeculectomy device group(n=4),and the right eye was the kahook dual blade device group(n=4).The two groups of isolated porcine eyes were continuously infused with a microinjection pump at a rate of2.5ml/h for 1 hour,and the baseline intraocular pressure was the stable intraocular pressure.The new minimally invasive internal trabecular resection device and the kahook dual blade were used to remove the trabecular mesh tissue 90° above the eyes of porcine in two groups,and pressure sensors were used to monitor the changes in intraocular pressure in real time and recorded once every minute.After 1 hour,another 90° trabecular mesh was removed with two surgical devices,respectively,and changes in intraocular pressure were monitored again.The effect of the two devices on efflux function was evaluated assuming that the external scleral venous pressure and uveo-scleral efflux were zero.(Calculated according to Goldmann equation(Tian,Bet al 2006))2.To explore the influence of the new minimally invasive internal trabeculectomy device on the external drainage rateSix fresh isolated porcine eyes were taken and divided into left and right eyes according to eyelid and appendage,and divided into two groups: the left eye was the new minimally invasive internal trabeculectomy device group(n=3),and the right eye was the kahook dual blade group(n=3).The new minimally invasive internal trabecular resection device and the kahook dual blade were used to remove the upper 90° trabecular mesh,and The rate of external drainage was evaluated by means of average fluorescence intensity measured by monochromatic dye perfusion contrast.ResultsBoth surgical devices can reduce intraocular pressure,enhance outflow function,and increase the rate of external drainage to some extent,and this effect is more significant in the first operation.After the first surgical resection of the trabecular meshwork,intraocular pressure decreased from baseline22.25±0.88 mm Hg to 9.55±0.55 mm Hg in the minimally invasive trabeculectomy group,and outflow function increased from baseline 0.11±0.00 to 0.28±0.02.In the kahook dual blade device group,intraocular pressure decreased from 23.00±0.91 mm Hg to 10.00±1.47 mm Hg,and outflow function increased from 0.11±0.00 to 0.27±0.02.However,the second resection of trabecular meshwork only resulted in a slight decrease in intraocular pressure and enhanced outflow function,and there was no statistical significance between the two groups(P>0.05).After Texas red was injected into the two groups of treated porcine eyes under a certain gravity,a certain degree of fluorescence outflow could be observed in both groups,and this fluorescence outflow would be more significant with the extension of observation time,but there was no statistical significant difference between the two groups(P>0.05).ConclusionIn the ex vivo porcine eye perfusion model,the new minimally invasive internal trabeculectomy device and the kahook dual blade device showed similar reduction of intraocular pressure and enhancement of outflow function after trabeculectomy,which may indicate that the minimally invasive internal trabeculectomy device is a feasible and effective surgical method for the treatment of glaucoma.