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PubMed1994

Light microscopy techniques for the demonstration of silicone gel.

Because of the difficulty in identifying silicone gel in histologic and cytologic specimens by means of conventional light microscopy, we investigated alternative light microscopy techniques, as well as specimen staining and preparation. Specimens from six periprosthetic capsules, one silicone granuloma specimen, and one synovial biopsy specimen obtained from women with silicone breast implants were cut at 4-, 10-, 20-, and 30-microns sections, stained with a variety of common stains, and correlated with electron probe microanalysis. In addition, a commercial silicone gel and silicone gel extracted from a previously implanted silicone breast prosthesis were smeared and examined unstained or stained with Papanicolaou and Diff Quik. Silicone was noted to be refractile, nonpolarizable, and nonstainable. Thicker sections prevented silicone "dropout" during processing and increased the contrast between stained tissue and unstained silicone (negative staining). The relative ease of silicone identification was greatly increased with non-Koehler, phase contrast, and darkfield microscopy. Staining the mounting media of hematoxylin-eosin-stained sections with a nonparticulate commercial ink allowed enhanced negative staining detection of silicone gel.

Breast↗
PubMed1998

[Silicone breast prosthesis and rheumatoid arthritis: a new systemic disease: siliconosis. A case report and a critical review of the literature].

Today the number of women receiving breast implants of silicone gel, for augmentation or reconstruction of the breast, is increasing. Silicon implants may cause local complications (such as capsular contracture, rupture, closed capsulotomy, gel "bleed", nodular foreign body granulomas in the capsular tissue and lymph nodes) or general symptoms. An adverse immune reaction with signs and symptoms of rheumatoid disorders is also possible, although an increased frequency of true autoimmune systemic connective tissue diseases is controversial. The US Food and Drug Administration advised that these silicone implants should be used only in reconstructive surgery and as part of clinical trials. Silicone is not an inert substance and silicone compounds were found in the blood and liver of women with silicone breast implants. The development of disease related to silicone implants would depend on genetic factors, so that only a very few women are potentially at risk. HLA-DR53 may be a marker of predisposed subjects. Breast-feeding by women with silicone implants should not be recommended for possible autoimmune disorders in the children. We report the case of an adult female patient with silicone breast implantation for bilateral mastectomy (performed 12 months before) and a unique syndrome characterized by low-grade fever, chronic fatigue, arthralgias of the hands, dysphagia, dry eye, increased level of rheumatoid factor and decreased value of complement C3 and C4. No increased erythrocyte sedimentation rate occurred, and no ANA, nDNA, ENA and AAT autoantibodies were evidence. A critical review of literature (source: MEDLINE 1980-1997) was performed and our case seems to be the first one reported in Italy. The internist should become familiar with the immunological disorders related to silicone breast implants, often so marked to require the explantation of the prostheses to improve symptomatology. However, perhaps due to the leak and spreading of silicone, the progression to a severe systemic involvement may remain despite the implant removal.

Adult↗
PubMed2002

(29)Si NMR shifts and relative stabilities calculated for hypercoordinated silicon-polyalcohol complexes: role in sol-gel and biogenic silica synthesis.

Penta- and hexa-coordinated silicon is rare, occurring as a transient species in some glasses, nonaqueous organosilicon solutions and organosilicon gels such as silicone, and is stable at high pressures within the earth in dense phases such as stishovite. The stable form expected in aqueous solution is quadra-coordinated silicon. A recent study proposed the existence of hypercoordinated silicon-polyalcohol complexes in aqueous solution, based on (29)Si NMR shifts at -102 to -103 ppm and -145 to -147 ppm. Here, we report ab initio molecular orbital calculations of (29)Si NMR chemical shifts and relative stabilities of silicon-polyalcohol monocyclic and spirocyclic complexes, from ethylene glycol (C(2)H(6)O(2)) to arabitol (C(5)H(12)O(5)) with Si in quadra-, penta- and hexa-coordination ((Q)Si, (P)Si, (H)Si), calculated at the HF/6-311+G(2d,p)//HF/6-31G* level. Calculated shifts are accurate with a 1-8% error for (Q)Si and 2-9% for (P)Si. Shifts calculated for the hypercoordinated silicon complexes having structures proposed in the literature are much more negative (-128 and -180 ppm for (P)Si and (H)Si) than observed. We propose that cyclic trimers complexed by polyalcohols can explain the -102 ppm shift, where the Si atoms are all (Q)Si, or where two silicons are (Q)Si and one is (P)Si with rapid exchange between the Si sites. The -145 ppm resonance results from structures similar to those proposed in the experimental NMR study for the -102 ppm peak. Our relative stability calculations indicate that structures proposed in the literature for hypercoordinated silicon complexes are thermodynamically unstable in aqueous solution at acidic to neutral conditions but may exist in degrading silicone-gel breast-implants. Thus, aqueous hypercoordinated silicon-polyalcohol complexes are unlikely to play an important role in biological silicon uptake and hold little promise for novel silica synthesis routes from aqueous solutions under nonextreme conditions.

Journal Article↗
PubMed2006

Strained silicon as a new electro-optic material.

For decades, silicon has been the material of choice for mass fabrication of electronics. This is in contrast to photonics, where passive optical components in silicon have only recently been realized. The slow progress within silicon optoelectronics, where electronic and optical functionalities can be integrated into monolithic components based on the versatile silicon platform, is due to the limited active optical properties of silicon. Recently, however, a continuous-wave Raman silicon laser was demonstrated; if an effective modulator could also be realized in silicon, data processing and transmission could potentially be performed by all-silicon electronic and optical components. Here we have discovered that a significant linear electro-optic effect is induced in silicon by breaking the crystal symmetry. The symmetry is broken by depositing a straining layer on top of a silicon waveguide, and the induced nonlinear coefficient, chi(2) approximately 15 pm V(-1), makes it possible to realize a silicon electro-optic modulator. The strain-induced linear electro-optic effect may be used to remove a bottleneck in modern computers by replacing the electronic bus with a much faster optical alternative.

Journal Article↗
PubMed2005

Effect of high-energy electron-beam irradiation on the optical properties of ion-beam-sputtered silicon oxynitride thin films.

Silicon oxynitride thin films are prepared by ion-beam sputtering, and the optical properties and surface chemical composition are studied by spectrophotometric and x-ray photoelectron spectroscopy, respectively. It is seen that the films sputtered by use of nitrogen alone as the sputtering species from a silicon nitride target are completely transparent (k < 0.005) and have a refractive-index dispersion from 1.85 to 1.71 over the visible and near-infrared spectral regions, and the films show distinct spectral lines that are due to silicon, Si(2s), nitrogen, N(1s), and oxygen, O(1s). Sputter deposition of argon and of argon and nitrogen produces silicon-rich silicon oxynitride films that are absorbent and have high refractive indices. These films have a direct electronic transition, with a threshold energy of 1.75 eV. Electron irradiation transforms optically transparent silicon oxynitride films into silicon-rich silicon oxynitride films that have higher refractive indices and are optically absorbing owing to the presence of nonsaturated silicon in the irradiated films. The degradation in current responsivity of silicon photodetectors, under electron irradiation, is within 3% over the wavelength region from 450 to 750 nm, which is entirely due to the degradation of optical properties of silicon oxynitride antireflection coatings.

Journal Article↗
PubMed2004

Effect of hydrophilic coating on microorganism colonization in silicone tubing.

BACKGROUND: Shunt infections are one of the major causes of mortality and morbidity of patients with hydrocephalus. The aim of this research is to compare the bacterial colonization characteristics of a regular silicone elastomer shunt material coated with polyvinylpyrrolidone and dimethylpolysiloxane (silicone). METHOD: Regular coated shunt materials were compared by in-vivo and in-vitro methods. In the in-vitro experiment, silicone and coated material immersed and not immersed in vancomycin solution was treated with a certain concentration of Staphylococcus epidermidis. In the in-vivo study, silicone and coated material specimens were treated with Staphylococcus epidermidis and they were stereotactically placed in the lateral ventricles of the rats. One week after the inoculation, shunt pieces were removed and the colonies were counted by using a scanning electron microscope. FINDINGS: There was a statistically significant difference of colonization in the in-vitro groups in coated material vs. silicone, coated material vs. vancomycin treated silicone, vancomycin treated coated material vs. silicone, vancomycin treated coated material vs. vancomycin treated silicone. There was no statistically significant difference for colonization in in-vitro groups of coated material and vancomycin treated coated material. With in-vivo experiments we can say that, coated material catheters are superior than the silicone catheters in respect to colonization but after the bacterial colonization has occurred, the amount of colonization did not differ. INTERPRETATION: Coated material catheters are superior to silicone catheters and they prevent bacterial colonization in some respect.

Animals↗
PubMed1997

Silicone oil adhesion to intraocular lenses: an experimental study comparing various biomaterials.

PURPOSE: To perform an in vitro experimental study comparing the degree of adherence of silicone oil to various rigid and foldable intraocular lens (IOL) designs and to the human lens capsule. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Seven IOL styles comprising various biomaterials were studied: fluorine-treated (Fluorlens), heparin-surface-modified (HSM), hydrogel, Memory-Lens, Poly(methyl methacrylate) (PMMA), soft acrylic, and silicone lenses; the human crystalline lens was also studied. Each lens was immersed in silicone oil for 12 hours, than photographed, studied by scanning electron microscopy (except the crystalline lens), and subjected to computer-generated image analysis to determine the silicone oil coverage. RESULTS: Silicone oil coverage of dry silicone lenses was 100% and of lenses immersed in normal saline, 82.5%. The least coverage was on the heparin-surface-modified lens (mean score 9.4%). Coverage of the other four lenses ranged from approximately 15.1% to 33.7%. Mean coverage of the human lens capsule was 10.9%. CONCLUSION: Although a silicone IOL shows maximal adherence to silicone oil, other lens biomaterials are not immune to this complication. Silicone oil coverage was related to the dispersive energy component of the surface charge of the IOL biomaterial. Low dispersive energy materials had less silicone oil coverage, while those with higher dispersive energy had more oil coverage.

Adhesiveness↗
PubMed2003

Injecting 1000 centistoke liquid silicone with ease and precision.

BACKGROUND: Since the Food and Drug Administration approved the use of the 1000 centistoke liquid silicone, Silikon 1000, for intraocular injection, the off-label use of this injectable silicone oil as a permanent soft-tissue filler for facial rejuvenation has increased in the United States. Injecting liquid silicone by the microdroplet technique is the most important preventive measure that one can use to avoid the adverse sequelae of silicone migration and granuloma formation, especially when injecting silicone to improve small facial defects resulting from acne scars, surgical procedures, or photoaging. OBJECTIVE: To introduce an easy method for injecting a viscous silicone oil by the microdroplet technique, using an inexpensive syringe and needle that currently is available from distributors of medical supplies in the United States. METHOD: We suggest the use of a Becton Dickinson 3/10 cc insulin U-100 syringe to inject Silikon 1000. This syringe contains up to 0.3 mL of fluid, and its barrel is clearly marked with an easy-to-read scale of large cross-hatches. Each cross-hatch marking represents either a unit value of 0.01 mL or a half-unit value of 0.005 mL of fluid, which is the approximate volume preferred when injecting liquid silicone into facial defects. Because not enough negative pressure can be generated in this needle and syringe to draw up the viscous silicone oil, we describe a convenient and easy method for filling this 3/10 cc diabetic syringe with Silikon 1000. RESULTS: We have found that by using the Becton Dickinson 3/10 cc insulin U-100 syringe, our technique of injecting minute amounts of Silikon 1000 is facilitated because each widely spaced cross-hatch on the side of the syringe barrel is easy to read and measures exact amounts of the silicone oil. These lines of the scale on the syringe barrel are so large and clearly marked that it is virtually impossible to overinject the most minute amount of silicone. CONCLUSION: Sequential microdroplets of 0.01 cc or less of Silikon 1000 can be measured and injected with the greatest ease and precision so that inadvertent overdosing and complications can be avoided.

Dimethylpolysiloxanes↗
PubMed2006

Silicon inhibition effects on the polymerase chain reaction: a real-time detection approach.

In the miniaturization of biochemical analysis systems, biocompatibility of the microfabricated material is a key feature to be considered. A clear insight into interactions between biological reagents and microchip materials will help to build more robust functional bio-microelectromechanical systems (BioMEMS). In the present work, a real-time polymerase chain reaction (PCR) assay was used to study the inhibition effects of silicon and native silicon oxide particles on Hepatitis B Virus (HBV) DNA PCR amplification. Silicon nanoparticles with different surface oxides were added into the PCR mixture to activate possible interactions between the silicon-related materials and the PCR reagents. Ratios of silicon nanoparticle surface area to PCR mixture volume (surface to volume ratio) varied from 4.7 to 235.5 mm2/microL. Using high speed centrifugation, the nanoparticles were pelleted to tube inner surfaces. Supernatant extracts were then used in subsequent PCR experiments. To test whether silicon materials participated in amplifications directly, in some cases, entire PCR mixture containing silicon nanoparticles were used in amplification. Fluorescence histories of PCR amplifications indicated that with the increase in surface to volume ratio, amplification efficiency decreased considerably, and within the studied ranges, the higher the particle surface oxidation, the stronger the silicon inhibition effects on PCR. Adsorption of Taq polymerase (not nucleic acid) on the silicon-related material surface was the primary cause of the inhibition phenomena and silicon did not participate in the amplification process directly.

Hepatitis B virus↗
PubMed2005

Monolayer-derivative functionalization of non-oxidized silicon surfaces.

This article describes a variety of monolayers anchored directly onto silicon surfaces without an oxide interlayer, their formation mechanisms, their technological applications, and our personal views on the future prospects for this field. The chemical modification of non-oxidized silicon surfaces utilizing monolayers was first reported in 1993. The basic finding that a non-oxidized silicon surface could be neutralized with alkyl chains through direct covalent linkage, i.e., silicon-carbon, has offered chemical scientists ease of handling even in an ambient environment and, thus, research has been predictably focused on forming anti-stiction coating films for nano- and micro-electromechanical systems (NEMS/MEMS). Such surface reforming has also been achieved by using other monolayers, which form interfacial bonds, e.g., silicon-nitrogen and silicon-oxygen. The resultant monolayer surfaces are useful for silicon-based applications including molecular electron transfer films, monolayer templates, molecular insulators, capsulators, and bioderivatives. Such monolayers are applicable not only for surface modification, but also for manipulating individual nanomaterials. By modifying the terminal groups of monolayers with nanomaterials including nanocrystals and biomolecules, the nanomaterials can remarkably be immobilized directly onto non-oxidized silicon surfaces based on the formation mechanisms of the monolayer. Such immobilizations will revolutionize the analysis of the specific features and capabilities of individual nanomaterials. Furthermore, the path will be opened for the development of more advanced monolayer-derived chip technology. To achieve this goal, it is extremely important to thoroughly understand the functionalization processes on silicon, since the resultant internal structures and properties of monolayer-derivative silicon may strongly depend on their course of formation.

Biocompatible Materials↗
PubMed1996

Silicone does not potentiate development of the scleroderma-like syndrome in tight skin (TSK/+) mice.

Several reports have implicated an association between the development of connective tissue disorders and exposure to silicone in breast implant patients. These connective tissue disorders include local or systemic scleroderma-like syndrome and have been characterized by fibrosis as well as the presence of circulating autoantibodies. Whether silicone does potentiate the development of a scleroderma-like syndrome is still to be defined. The purpose of the present study was to determine the effect of silicone on the tight skin (TSK/+) mouse which develops a scleroderma-like syndrome and on its normal pa/pa TSK/- littermate. Groups of six TSK and five of their normal pa/pa littermates were injected subcutaneously with low molecular weight silicone (LMW-PDMS), high molecular weight silicone gel (HMW-PDMS), incomplete Freunds' adjuvant (IFA) or Hank's balanced salt solution (HBSS) in the dorsal neck area and ventrally in the upper chest region. Serum was obtained prior to and 1 month after injection of silicone, IFA, or control HBSS. Antibody levels to bovine serum albumin (BSA), RNA polymerase (RNAP) and topoisomerase I were determined. Mice were then euthanized and strips of skin from the injection sites as well as samples of kidney and liver were studied histologically. No significant pathological changes were observed in TSK/- mice 1 month following injection with HBSS, LMW-PDMS or HMW-PDMS. Skin samples from TSK/+ mice which received LMW-PDMS showed hyperplasia of the dermis and peri-panniculus carnosus tissue and infiltrates of macrophages containing lipid-like vacuolated materials. Lipid vacuoles were observed throughout the deeper dermis as multiple loculated vacuoles. TSK mice which received HMW-PDMS showed similar thickening of the dermis and the peri-panniculus carnosus connective tissue. There were no significant differences in the histologic characteristics of the silicone-injected TSK/+ mice compared to those that received HBSS or IFA. No detectable changes in the kidney, spleen, or liver samples taken from TSK/+ or TSK/- mice injected with HBSS, IFA or silicone (LMW-PDMS, HMW-PDMS) preparations were noted. Baseline circulating antibody levels to BSA, RNAP and topoisomerase were significantly higher in TSK/+ mice compared to the control TSK/- littermates. Administration of silicone (LMW-PDMS or HMW-PDMS) did not significantly alter circulating antibody levels to BSA, RNAP and topoisomerase in either the TSK/+ or the TSK/- mice. The results of this study indicate that silicone administration does not potentiate the development of the scleroderma-syndrome characterized by skin lesions and presence of circulating antibodies in the TSK/+ model.

Animals↗
PubMedDate not supplied

Residual silicone detection using MRI following previous breast implant removal: case reports.

The current controversy surrounding the safety of silicone gel breast implants has resulted in an increasing number being removed. Although previous reports have suggested that remnants of the implant capsule are reabsorbed after explantation surgery, the persistence of the capsule in fact may be associated with implant fragments and silicone gel leakage. In this study we have used magnetic resonance imaging (MRI) to identify residual silicone gel and silicone granulomas following the removal of silicone gel breast implants. Four representative clinical case reports are presented. These patients, who had residual silicone present in their bodies, presented to us with breast pain, palpable masses, or abnormal calcific mass densities apparent on a mammogram. High-resolution MRI images were found to be helpful in identifying local and remote collections of silicone gel, silicone granulomas, and residual capsules that were incompletely removed from previous explantation surgery. MRI breast images demonstrated high resolution and provided the accurate anatomical locations of residual silicone gel and silicone granulomas in all the regions of breast parenchyma, chest wall muscles, and axillae. Patients with persistent local symptoms following explantation surgery may benefit from an evaluation of the breast using MRI.

Adult↗
PubMed1988

Silicon as a trace nutrient.

Silicon performs an important role in connective tissue, especially in bone and cartilage. Silicon's primary effect in bone and cartilage appears to be on formation of the organic matrix. Bone and cartilage abnormalities are associated with a reduction in matrix components, resulting in the establishment of a requirement for silicon in collagen and glycosaminoglycan formation. Additional support for silicon's metabolic role in connective tissue is provided by the finding that silicon is a major ion of osteogenic cells, especially high in the metabolically active state of the cell. Further studies also indicate that silicon participates in the biochemistry of subcellular enzyme-containing structures. Silicon also forms important relationships with other elements. Although it is clear from the body of recent work that silicon performs a specific metabolic function, a structural role has been proposed for silicon in connective tissue. A relationship established between silicon and aging probably relates to glycosaminoglycan changes.

Aging↗
PubMed1997

Characterization of cellular response to silicone implants in rats: implications for foreign-body carcinogenesis.

Foreign-body (FB) carcinogenesis is a classic model of multistage tumour development in rodents. Previous studies have demonstrated that the physical characteristics of the implant, and not the chemical composition, are the critical determinants of tumour development. The recent controversy over silicone breast implants has raised questions regarding the potential carcinogenicity of lifetime tissue exposure to silicone products. The present study was designed to determine whether the inflammatory and fibrotic reactions associated with silicone implants are due to a non-specific foreign-body reaction or whether these responses reflect the unique chemical composition of silicone. F344 rats were implanted subcutaneously with one of three biomaterials: silicone elastomer (Group 1); impermeable cellulose acetate filters (Group 2, positive control); or porous cellulose acetate filters (Group 3, negative control). The silicone and cellulose implants of Groups 1 and 2 have been previously shown to induce fibrosarcomas in rodents, whereas the porous cellulose acetate implants of Group 3 have been shown to be non-carcinogenic. One week and two months after implantation, the pericapsular tissues were evaluated using histopathological and in situ immunohistochemical analyses. Endpoints included expression of leucocyte antigens CD4 (T helper/inducer), CD8 (T suppressor/cytotoxic) and CD11 b/c (macrophage), proliferating cell nuclear antigen (PCNA) as an indicator of proliferation, and in situ end-labelling (ISEL) of 3'OH DNA strand breaks as an indicator of DNA damage and apoptosis. The results indicated that the acute and chronic cellular responses to silicone (Group 1) were not different from impermeable cellulose filters (Group 2) of identical size and shape, suggesting that these responses were not unique to silicone. The inflammatory response to the carcinogenic cellulose and silicone implants (Groups 1 and 2) was attenuated and associated with the formation of a thick fibrotic capsule. In contrast, the porous cellulose filters (Group 3) induced a markedly different cellular response in which the inflammatory reaction was more extensive, prolonged and associated with minimal fibrosis. Within the fibrotic capsule surrounding the tumorigenic implants, but not the non-tumorigenic implants, cell proliferation and apoptotic cell death were increased and associated with persistent DNA strand breaks. Taken together, the results suggest that the micrometre-scale surface morphology of the implant determines the nature of the subsequent cellular response which may predispose to tumour development. Further, these studies serve to emphasize the critical importance of appropriate physical controls in studies designed to evaluate carcinogenic or autoimmune manifestations associated with silicone implants in order to rule out the contribution of the chronic foreign-body reaction.

Acute Disease↗
PubMed1998

Cataract surgery combined with transpupillary silicone oil removal through planned posterior capsulotomy.

OBJECTIVE: The purpose of the study was to evaluate transpupillary removal of silicone oil combined with cataract surgery in patients after pars plana vitrectomy. DESIGN: A prospective case-control study. PARTICIPANTS: Fifty consecutive patients underwent cataract surgery combined with removal of silicone oil, which had served as intraocular tamponade after pars plana vitrectomy. In 28 patients, silicone oil was removed through a planned posterior capsulotomy, and in 22 patients, silicone oil was removed through pars plana sclerotomies. All patients were operated on by the same surgeon. INTERVENTIONS: Pars plana vitrectomy, cataract surgery, and silicone oil removal were performed. MAIN OUTCOME MEASURES: Frequencies of retinal redetachment, secondary cataract, cystoid macular edema, and vitreous hemorrhage; visual acuity; intraocular pressure; and duration of surgery and visual rehabilitation were measured. RESULTS: Frequencies of postoperative vitreous hemorrhage (1 of 28 [4%] vs. 10 of 22 [45%]) and secondary cataract (0 of 28 vs. 6 of 22 [27%]) were significantly lower (P < 0.05; chi-square test), and duration of surgery and visual rehabilitation were significantly shorter (P < 0.01) for patients with transpupillary silicone oil removal than for patients with drainage of silicone oil through pars plana sclerotomies. Rate of retinal redetachment (4 of 28 [14%] vs. 4 of 22 [18%]), time of retinal redetachment (36 +/- 32 postoperative days vs. 54 +/- 65 days), frequency of dislocated intraocular lenses (1 of 28 vs. 0 of 22), and postoperative visual acuity did not vary significantly between the two groups. Persisting comeal endothelial decompensation and clinically significant cystoid macular edema due to cataract surgery were not observed in any patient. CONCLUSIONS: Silicone oil removal can be combined with cataract surgery. In view of a decreased frequency of postoperative vitreous hemorrhage, reduced rate of secondary cataract, and shorter duration of surgery and visual rehabilitation, transpupillary drainage of silicone oil through a planned posterior capsulotomy compares favorably with removal of silicone oil through pars plana sclerotomies. Retinal redetachment usually occurs within the first 3 postoperative months.

Adolescent↗
PubMed2006

[Management of complicated retinal detachment using a heavy silicon oil as temporary tamponade].

PURPOSE: To assess the efficacy and safety of a heavy silicon oil (a silicon oil-RMN3 mixture, a mixed fluorinated and hydrocarbonated olefin) as temporary internal tamponade in selected cases of retinal detachment with inferior breaks. PATIENTS AND METHODS: Forty-six patients were operated on (inferior and/or posterior breaks: 38; proliferative vitreoretinopathy > or =C2: 18; anterior proliferative vitreoretinopathy: 14), with a mean follow-up of 39 months. Seventeen patients were operated on with a heavy silicon oil of a 1.03 g/cm3 density and 29 patients with a silicon oil of a 1.02 g/cm3 density. Heavy silicon oil was removed in 41 patients after a mean of 9.3 weeks. RESULTS: Anatomic success was achieved in 35 cases after a mean follow-up of 39 months. Recurrent retinal detachment with proliferative vitreoretinopathy occurred in eight cases during heavy silicon oil tamponade. The removal was difficult in three cases with the 1.02 g/cm3 density silicon oil. Complications included glaucoma (eight eyes), major emulsification (two eyes), and an intraocular inflammation reaction to topical steroids (five eyes). CONCLUSION: Heavy silicon oil (Oxane Hd) is as safe and effective as standard silicon oil in the treatment of selected retinal detachment, but intraocular manipulations are quite difficult. A prospective study is necessary to compare the efficacy of Oxane Hd and standard silicon oil in selected cases of retinal detachment with inferior breaks and in cases of large inferior retinectomy.

Adolescent↗
PubMed1991

Removal of silicone oil--rewards and penalties.

Silicone oil is a useful tool in retinal reattachment surgery in selected cases, but complications, particularly cataract, glaucoma and keratopathy, have led to worries about its use for prolonged internal tamponade. Removal of silicone oil has been recommended to preempt or reverse these complications. A retrospective review of 120 eyes in which temporary silicone oil tamponade had been employed is presented. One hundred and twelve eyes were examined six months and two years after removal of silicone oil. Retinal redetachment occurred in 21 eyes (19%). Cataract formation was delayed by early removal of silicone oil, but after two years the majority of eyes had undergone surgery for cataract or had developed lens opacities. Removal of silicone oil was ineffective in reversing an established pressure rise in nearly all cases. Three phakic eyes developed glaucoma after removal of silicone oil but no new cases occurred in phakic eyes in the two years following silicone oil removal. Keratopathy was uncommon and was arrested and occasionally reversed by silicone oil removal. Visual acuities improved in the majority of eyes after removal of silicone oil.

Adult↗
PubMed1997

Prophylactic argon laser retinopexy prior to removal of silicone oil: a pilot study.

BACKGROUND: Removal of silicone oil following successful retinal detachment surgery is usually performed in an attempt to prevent the complications of silicone oil; however, removal of the oil may result in retinal redetachment. PURPOSE: The purpose of this study was to determine whether argon laser retinopexy, 3-6 weeks prior to the removal of silicone oil, reduces the rate of retinal detachment following silicone oil removal. METHODS: A total of 31 eyes of 31 consecutive patients were followed up for a 12 month period after the removal of silicone oil. All patients had undergone retinal reattachment surgery resulting in a clinically attached retina with the absence of residual retinal traction prior to silicone oil removal. A study group of 15 of the 31 eyes received two rows of 360 degrees of peripheral argon laser retinopexy 3-6 weeks before removal of the silicone oil. The 16 eyes of the previous 16 consecutive patients, who underwent removal of silicone oil without argon laser retinopexy, were used as a control group. RESULTS: In the study group 1 of 15 eyes (6.7%) redetached following the removal of silicone oil and 4 of 16 (25%) redetached in the control group during the 12 month follow-up period from operation. CONCLUSIONS: Prophylactic argon laser retinopexy applied 3-6 weeks before the removal of silicone oil appears to reduce the retinal redetachment rate. A larger prospective randomised trial is needed to confirm these findings.

Adolescent↗