Research progress of finite element method in the biomechanics of the orbit / 国际眼科杂志(Guoji Yanke Zazhi)

The finite element method(FEM)is a widely employed mathematical technique in mechanical research that divides an object into discrete and interacting finite elements. Medically, finite element analysis(FEA)enables the simulation of biomechanical experiments that are challenging to conduct. Orbital surgery poses significant challenges to ophthalmologists due to its inherent difficulty and steep learning curve. FEM enables the simulation and analysis of the mechanical properties of orbital tissue, offering a novel approach for diagnosing and treating orbital-related diseases. With technological advancements, FEM has significantly matured in the diagnosis and treatment of orbital diseases, becoming a popular area of research in orbital biomechanics. This paper reviewed the latest advancements in orbital FEM, encompassing the development of orbital FEA models, simulation of orbital structure, and its application in orbital-related diseases. Additionally, the limitations of FEM and future research directions are also discussed. As a digital tool for auxiliary diagnosis and treatment, orbital FEA will progressively unlock its potential for diagnosing and treating orbital diseases alongside technological advancements.

Comparison between endoscopic surgery and glucocorticoid therapy for traumatic optic neuropathy: a meta-analysis / 中华实验眼科杂志

Objective:To systematically analyze the efficacy of nasal endoscopic transsphenoidal decompression and glucocorticoid pulse therapy for traumatic optic neuropathy (TON).Methods:PubMed, Web of Science, Cochrane Library, ClinicalTrial.gov, CNKI, Wanfang, China Biomedical and other databases were searched to retrieve clinical studies on endoscopic surgery and hormone therapy for TON since their establishment to November 1, 2020.Two researchers screened the literature and evaluated the quality of the included literatures.The improvement of visual acuity before and after treatment was taken as an effective indicator.RevMan 5.3 statistical software was used for meta-analysis.The sensitivity of the results was analyzed atfer literature exclusion.The publication bias of each study was double checked by funnel plot and Begg test.Results:Eight studies were included, including 7 cohort studies and 1 randomized controlled trial.There was no significant difference between the endoscopic decompression group and glucocorticoid group in the efficiency of visual acuity improvement in the treatment of TON [odds ratio ( OR)=1.65, 95% confidence interval ( CI)∶0.75-3.66, P=0.22], neither in TON patients with residual vision before surgery ( OR=2.17, 95% CI: 0.94-4.98, P=0.07). For nasal endoscopic decompression surgery, early surgery (disease course<7 days) was more effective than late surgery (disease course>7 days) ( OR=4.73, 95% CI: 2.55-8.78, P<0.01). Sensitivity analysis suggested that the results of this literature analysis were not robust.The Begg test showed that there was no literature publication bias. Conclusions:There is no significant difference between nasal endoscopic surgery and glucocorticoid therapy in the treatment of TON.Early endoscopic surgery may help improve visual acuity in patients with residual vision.

Research progress on protective strategies for optic nerve injury / 中华实验眼科杂志

Traumatic optic neuropathy and glaucoma can cause optic nerve degenerative changes leading to a significant decline in vision, which seriously affects the quality of life of patients.In recent years, research on mammalian optic nerve injury models has found that optic nerve injury involves pathophysiological processes such as apoptosis, inflammatory response, and oxidative stress.Researchers have explored the relevant mechanisms and regulatory signaling pathways of optic nerve injury, and have conducted research on the protection of optic nerve injury in the fight against retinal ganglion cell (RGC) apoptosis, new drug therapy, gene therapy, stem cell transplantation and natural extracts.Studies have shown that glucose regulatory protein 75, a member of the heat shock protein 70 family, and melatonin naturally secreted in the human retina may play an important role in the regulation of RGC apoptosis.Human granulocyte colony-stimulating factor (G-CSF) may play a protective role in RGC by directly activating the intrinsic G-CSF receptor and downstream signaling pathway.Targeting gene therapy is expected to become a powerful therapy for repair and regeneration of injured optic nerve.Adipose stem cell transplantation can resist the apoptosis of retinal cells in rat model.In addition, lycium barbarum polysaccharide can delay the secondary degeneration of axons, which may be a promising natural extract to delay the secondary degeneration of optic nerve injury.This article summarized the mechanism, regulation and protection of optic nerve injury.

New progress in the orbital tumor treatment technology / 中华实验眼科杂志

Orbital tumors not only damage the appearance of patients, but also damage the visual function, even endanger the life of patients.Orbital tumors can be divided into epidermal ectoderm, neuroectoderm, mesoderm, lymphopoietic system and metastatic tumors according to their origin.Due to the complex structure of orbital tissue, abundant nerve vessels and close connection with visual organs, it is more difficult and risky to treat orbital tumors than other regional tumors.Classic treatments for tumors include surgical resection, chemotherapy, and radiotherapy.Surgery is the main treatment for most orbital tumors.Due to the improvement of technology and equipment, it has been developed in the direction of minimally invasive surgery.For advanced tumors or lymphoid hematopoietic system tumors with extensive invasion, chemotherapy is the main treatment.Due to the improvement of drug delivery methods and protocols, it is developing towards high efficiency and less side effects.Radiotherapy is mostly used for refractory tumors that are difficult to be completely removed by surgery and easy to relapse.Due to the continuous improvement of radiotherapy technology, safe and accurate treatment has been achieved.In addition to the classical treatment methods, targeted treatment of carcinogenic sites at the molecular level has become a hot topic in the treatment of orbital tumors.This paper reviews the current development of orbital tumors in surgical resection, chemotherapy, radiotherapy and targeted therapy.

Evaluation of bFGF collagen composite sponge promoting vascular ingrowth in orbital implantation by 99Tcm-MDP scan / 中华实验眼科杂志

Background Intraorbital implantation of coralline porous hydroxyapatite (CHA) is a favorable cosmetic method after enucleation.However,the low degree of vascularizatiou in implant results in implant infection and exposure.Studies showed that a collagen composite sponge treated by basic fibroblast growth factor (bFGF/ collagen composite sponge) can promote angiogenesis.However,whether bFGF/collagen composite sponge improves the vascularization of CHA implants is unclear.Objective This study was to investigate the accelerating effect of bFGF collagen composite sponge on vascularization of orbital implant made of CHA using 99Tcm-methylene diphosphate (MDP) scan.Methods Forty-five New Zealand rabbits were randomly assigned to 3 groups.Evisceration of eyeball was performed on the left eyes of rabbits,and naked CHA,collagen composite sponge wrapped CHA and bFGF/collagen composite sponge wrapped CHA were implanted into the orbit respectively in 3 groups.99Tcm-MDP of 3 mCi was injected in the rabbits via ear vein in 2,4,6,8 and 12 weeks,and the vascular enhancement intensity on implants was observed 3 hours after injection.The ratio of average radioactive count from the area of interest with the same size between the left eyes and the right eyes was calculated.The implants were extracted for histopathological examination in the 12 weeks.Results As the lapse of postoperative time,the inflammation response gradually disappeared and no exposure of implants was seen during the 12-week duration.A similar vascular development strength was found in the area of interest among the 3 groups 2 weeks after surgery.However,the vascular development was significantly enhanced in the left eyes compared the right eyes from 4 to 6 weeks,with the highest intensity in the 8th week in the naked CHA group and collagen composite sponge wrapped CHA group.In the bFGF/ collagen composite sponge wrapped CHA group,the strongest image was in the 6th week after operation.The ratios of average radioactive count between the left eyes and the right eyes were significantly higher in the bFGF/collagen somposite sponge wrapped CHA group compared with the naked CHA group and collagen composite sponge wrapped CHA group (all at P＜0.05),and ratios of average radioactive count of the collagen composite sponge wrapped CHA group was significantly higher than that of the naked CHA group (all at P＜0.05).New blood vessels ingrowed toward the center of the implants through the coralline porous under the optical microscope.Conclusions Both bFGF (20 μg)/collagen composite sponge and collagen composite sponge can accelerate the ingrowth of vessel in the CHA,but the promoting effect of bFGF collagen composite sponge is prominent.

Effects of basic fibroblast growth factor composite sponge treated collagen on vascularization of orbital implants: a histopathologic analysis / 中华病理学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of basic fibroblast growth factor (bFGF) treated collagen composite sponge on vascularization of HA orbital implants.</p><p><b>METHODS</b>New Zealand rabbits received three different orbital implants:naked implants, implants wrapped with collagen composite sponge and implants wrapped with bFGF treated collagen composite sponge.Implants were harvested 2, 4, 6, 8 and 12 weeks after surgery. The vascularization of implants was then assessed by light and electron microscopy.</p><p><b>RESULTS</b>At post-surgery weeks of 2, 4 and 6, bFGF treated collagen composite sponge induced the highest degree of vascularization of orbital implants. Collagen composite sponge alone resulted in higher extent of vascularization than naked implants. Complete vascularization of implants was observed at post-surgery 6 weeks by bFGF treated collagen composite sponge, which was not observed in the other two groups until post-surgery 8 weeks. There were significant differences in the average length of fibrovasculature and in the degree of vascularization among each group at post-surgery 2, 4 and 6 weeks (P<0.05), while no statistical difference was observed at post-surgery 8 and 12 weeks (P>0.05).</p><p><b>CONCLUSIONS</b>bFGF treated collagen composite sponge facilitates fibrovascularization of orbital implants, and shortens the time required for complete vascularization. Collagen composite sponge alone promotes early-stage fibrovascularization, but fails to facilitate complete vascularization of orbital implants.</p>

Experimental study of hydroxyapatite/ultra-high molecular weight polyethylene and high-density porous polyethylene used for reconstruction of orbit of rabbits / 中国医师杂志

Objective To compare the biocompatible and osteconduetian behavior of the high-density porous polyethylene and hydroxyapatite/ultra-high molecular weight polyethylene. Methods Osteoectomy of the upper orbital rim was performed on 60 adult Japan rabbits. The animals were randomly divided into 3 groups with 20 of each. The hydroxyapatite/ultra-high molecular weight polyethylene, high-density porous polyethylene was implanted to the upper orbital defect of the animals in respective group. Animals were sacrificed at the 1st, 2nd, 4th and 8th weeks. Alkaline phosphatase (ALP) and Osteocalcin (OC)in the HDPE and hydroxyapatite/ultra-high molecular weight polyethylene was also detected. Result During the experimental period of 8 weeks, there was no implants extrusion or displacement. Fibrous tissue and new vessels grew into HDPE were obviously elder than those grew into hydroxyapatite/ultra high molecular weight polyethy-lene. Alkaline phosphatase and osteocalcin contents has great difference, HDPE group is the best, followed by HA combination artificial group (P<0.05). Conclusions High-density porous polyethylene and hydroxyapatite/ultra-high molecular weight polyethylene are both good orbital reconstruction materials, they all have good biocompatiblity and osteoconductian, but high-density porous polyethylene is better than hydroxyapatite/ultra-high molecular weight polyethylene in osteoconductian.

Ophthalmic applications of hydroxyapatite and its polymer composites / 中国组织工程研究

Hydroxyapatite, as a biologically active material, has the same structure and ingredients as the inorganic of hard tissue in human body, moreover, its biocompatibility and biological activity of interface are better than other biological materials. Hydroxyapatite has been widely used in anophthalmus reconstruction, orbital reconstruction, artificial cornea transplant and drug carrier. Pure hydroxyapatite has some defects such as brittleness, low-bending strength, the strength of anti-fatigue and anti-sabotage in the physical environment are not high. In order to overcome or reduce these shortcomings, porous hydroxyapatite and composite hydroxyapatite are made to extent the clinical application of hydroxyapatite. With a variety optimization of performance, process and preparation of the composite materials, the hydroxyapatite/polymer tissue engineering materials in ophthalmology will be further developed.