Correlation between intraoperative and postoperative vaulting of the EVO implantable Collamer lens: a retrospective study of real-time observations of vaulting using the RESCAN 700 system.

BACKGROUND: Implantable Collamer lens (ICL) vaulting is one of the most important parameters for the safety, aqueous humor circulation, and lens transparency after ICL implantation. This study aimed to investigate the factors associated with the actual vaulting after refractive EVO-ICL surgery. METHODS: This retrospective study included patients who underwent EVO-ICL surgery at a tertiary eye hospital between October and December 2019. A RESCAN 700 was used for the intraoperative and CIRRUS HD-OCT was used for postoperative observation of vaulting. Subjective and objective refractions, anterior ocular segment, corneal morphology, intraocular pressure (IOP), anterior chamber volume (ACV), crystalline lens rise (CLR), white-to-white distance (WTW), anterior chamber depth (ACD), axial length, corneal endothelial cell density (ECD), and fundoscopy were examined. A multivariable analysis was performed to determine the factors independently associated with 1-month postoperative vaulting. RESULTS: Fifty-one patients (102 eyes) were included. Compared with the eyes with normal vaulting, those with high vaulting had higher preoperative diopter values (P = 0.039), lower preoperative corrected visual acuity (P = 0.006), lower preoperative IOP (P = 0.029), higher preoperative ACD (P = 0.004), lower preoperative CLR (P = 0.046), higher ICL spherical equivalent (P = 0.030), higher intraoperative vaulting (P < 0.001), and lower IOP at 1 month (P = 0.045). The multivariable analysis showed that the only factor independently associated with high vaulting at 1 month after surgery was the intraoperative vaulting value (odds ratio = 1.005, 95% confidence interval: 1.002-1.007, P < 0.001). The intraoperative and 1-month postoperative vaulting values were positively correlated (R2 = 0.562). CONCLUSIONS: The RESCAN700 system can be used to perform intraoperative optical coherence tomography to predict the vaulting value of ICL at 1 month.

Improved osteoblast proliferation, differentiation and mineralization on nanophase Ti6Al4V.

BACKGROUND: Previous studies have demonstrated increased functions of osteoblasts on nanophase materials compared to conventional ceramics or composites. Nanophase materials are unique materials that simulate dimensions of constituent components of bone as they possess particle or grain sizes less than 100 nm. However, to date, interactions of osteoblasts on nanophase materials compared to conventional metals remain to be elucidated. The objective of the present in vitro study was to synthesize nanophase metals (Ti6Al4V), characterize, and evaluate osteoblast functions on Ti6Al4V. Such metals in conventional form are widely used in orthopedic applications. METHODS: In this work, nanophase Ti6Al4V surfaces were processed by the severe plastic deformation (SPD) principle and used to investigate osteoblast long-term functions. Primary cultured osteoblasts from neonatal rat calvaria were cultured on both nanophase and conventional Ti6Al4V substrates. Cell proliferation, total protein content, and alkaline phosphatase (ALP) activity were evaluated after 1, 3, 7, 10 and 14 days. Calcium deposition, gene expression of type I collagen (Col-I), osteocalcin (OC), osteopontin (OP) and the production of insulin-like growth factor-I (IGF-I) and transforming growth factor-beta 1 (TGF-ß1) were also investigated after 14 days of culture. RESULTS: Functions of osteoblasts including proliferation, synthesis of protein, and ALP activity were improved on the nanophase compared to the conventional Ti6Al4V. The expression of Col-I, OC and OP mRNA was also increased on nanophase Ti6Al4V after 14 days of culture. Calcium deposition was the same; the average number of the calcified nodules on the two Ti6Al4V surfaces was similar after 14 days of culture; however, highly significant size calcified nodules on the nanophase Ti6Al4V was observed. Of the growth factors examined, only TGF-ß1 showed a difference in production on the nanophase surface. CONCLUSION: Nanophase Ti6Al4V surfaces improve proliferation, differentiation and mineralization of osteoblast cells and should be further considered for orthopedic implant applications.

[In vivo effect of nanophase Ti6Al4V on osseointegration: experiment with rabbits].

OBJECTIVE: To evaluate the effect of nanophase Ti6Al4V substrates on the osseointegration in vivo. METHOD: Novel nanophase Ti6Al4V substrates were prepared according to the severe plastic deformation principle. Eighteen New Zealand white rabbits were randomly divided into 3 equal groups with their trochanters of femur exposed and implanted with titanium substrate with common surface (Ti group), nanophase Ti6Al4V substrate (nano-Ti group), and hydroxyapatite-coated substrate (HA group) respectively. Four, 8, and 12 weeks later X-ray films were taken on 6 rabbits from each group, tetracycline and calcein were injected intramuscularly, and one day later the rabbits were sacrificed. The histological changes of the tissue surrounding the implant including the bone kinesics parameter were evaluated; the bone-implant interfaces were examined with scanning electron microscope (SEM) and transmission electron microscope (TEM) respectively. RESULT: Radiographic examinations showed that the bone recovery around the implant in the nano-Ti group was earlier compared to that in the Ti group. Histological examination suggested that the interface osseointegration rates 4, 8, and 12 weeks later of the nano-Ti groups were all significantly higher than those of the Ti group ( all P < 0.01). Strong tetracycline labeling and calcein labeling were observed around the implants in the nano-Ti group, indicating the active form action of new bone. The rates of bone mineralization and deposition 4, 8, and 12 weeks later of the nano-Ti group were higher than those of the Ti group. SEM and TEM examinations showed greater degradation of the surface and much more grains in cells in the HA group as compared to those in the nano-Ti group. The bone mineralization and osseointegration rates 4 weeks later of the HA group were significantly higher than those of the nano-Ti group (both P < 0.05), however, there were no significant differences in the bone mineralization and osseointegration rates 8 weeks later between these 2 groups. The bone mineralization and osseointegration rates 12 weeks later of the nano-Ti group were even higher than those of the HA group. CONCLUSION: The novel nanophase Ti6Al4V substrates improves the bone-implant osseointegration without significant grains of degradation in vivo, suggesting that the novel substrates and nano technology should be further considered for the orthopedic implant applications.

[The effects of nanostructured titanium fabricated via surface plastic deformation on Saos-2 cell adherence, proliferation and differentiation].

PURPOSE: To study the effects of nanostructured titanium fabricated via surface plastic deformation on Saos-2 cell adherence, proliferation and differentiation in vitro. METHODS: Nanostructured titanium surfaces were prepared using plastic deformation and divided into three groups: group I (30 minutes, n=6), group II (60 minutes, n=6) and group III (90 minutes, n=6), according to the time of preparation. The untreated titanium was used as control group. Saos-2 cell line was cultured on different titanium surfaces. The features of titanium surface and the effects of nanostructured titanium surfaces on cell adherence, proliferation and shape were examined using fluorescence microscope, LSCM and MTT tests. RT-PCR was used to assess the alteration of BMP-4 gene expression. The data was analyzed for ANOVA with SAS6.0 software package. RESULTS: The results of SEM showed that plastic deformation for 60 and 90 minutes yielded nanostructured titanium surface. The nanostructured titanium surface significantly promoted Saos-2 cell adherence (P<0.05). Group II (60 minutes) had more extensive spreading on titanium surfaces than the control group. Group II (60 minutes) and group III (90 minutes) had significantly higher BMP-4 gene expression in Saos-2 cells than control group (P<0.05). CONCLUSIONS: The biological behavior of Saos-2 cells on nanostructured titanium surface fabricated via plastic deformation for 60 minutes is better than other groups. Surface plastic deformation may be a potential method to yield nanostructured surface of titanium.

[Development of an electrolytically-detachable microcoil for intracranial aneurysms].

An electrolytically-detachable microcoil is introduced here in the paper. The testing results indicate that, the microcoils have stable mechanical properties, clear radiographic images and fine insulation performance. Their detaching time varies from 30s to 200s when voltage changes from 2V to 5V.

[Experimental study on the effects of chitosan on the conjunctiva scar formation and symblepharon].

OBJECTIVE: To study the effects of chitosan on preventing symblepharon, reducing conjunctiva scar formation and promoting epithelial healing in the treatment of keratoconjunctival alkali burn. METHODS: Keratoconjunctival alkali burn model of New Zealand rabbits was induced in the present study. Twenty-one rabbits were randomly selected from 26 rabbits to induce the alkali burn. Right eyes were treated with chitosan (treatment group), left eyes were non-treated (experimental control group). Five rabbits were used as normal control group. The symblepharon, conjunctiva scar formation and the inflammatory reaction of cornea and conjunctiva were observed by slit lamp. Histopathologic studies were performed 20 and 30 d after alkali burn. The amount of collagen in the conjunctiva and the scar formation process was evaluated by sirius red staining 30 d after alkali burn. RESULTS: The degrees of the symblepharon and conjunctiva scar formation in the treatment group were less than those in the experimental control group (u = 2.1159, P < 0.05). The amount of collagen in the conjunctiva was increased and the conjunctiva scar was formed after alkali burn, but the amount of collagen, which was evaluated by the area (Q = 32.1450, P < 0.01) and integral spectra (Q = 22.4767, P < 0.01) of sirius red staining in the treatment group was much lower than that of the experimental control group. CONCLUSION: Chitosan is effective in preventing symblepharon and reducing scar formation in the treatment of keratoconjunctival alkali burn.

[The effect of Chitosan on intraocular structure when filling in the vitreous cavity].

OBJECTIVE: To study the effect of Chitosan on intraocular structure and pressure when filling in the vitreous body. METHODS: Chitosan were injected into vitreous cavity in twelve healthy vitrectomized pigmented rabbits in the right eyes (experiment group) and Hyalumnan in the left eyes (control group). Slitlamp biomicroscopy and indirect ophthalmoscopy were performed and intraocular pressure were measured pre- and postoperatively in all eyes. Histopathological examination was done after the rabbits were sacrificed at the end of the study. RESULTS: All the results indicated that there were no significant differences between experiment group and control group. CONCLUSION: There is no obvious effect on intraocular structure and intraocular pressure when the vitreous cavity is filled with Chitosan.