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At least 865 records · Page 48Linked to original sources
PubMed1992

[Long-term results of successful surgical treatment of retinal detachment by vitrectomy and silicone oil injection. Effect of removal of the tamponade on further complications].

We present, with a minimal follow up of six months, the results of 118 silicone oil removals following successful treatment of retinal detachment by pars plana vitrectomy and silicone oil injection. A recurrent retinal detachment occurred in 8.5% of cases, 13% of the 61 phakic eyes at the time of silicone oil removal maintained a clear lens, 29.6% of the eyes had a raised intraocular pressure and 6.8% had a keratopathy. The visual acuity improved in 72.8% of eyes after silicone oil removal. The main reasons for a late decrease in visual acuity were recurrence of the detachment, hypertonia, chronic hypotonia and keratopathy. All the eyes with late complications after silicone oil removal had a clinically significant droplet dispersion in the anterior chamber. Only complete and early silicone oil removal seems to decrease the complication rate.

Adolescent↗
PubMedDate not supplied

Phacoemulsification and foldable intraocular lens implantation in eyes filled with silicone oil.

BACKGROUND AND OBJECTIVE: To evaluate the visual outcome of phacoemulsification and foldable intraocular lens (IOL) implantation in eyes already filled with silicone oil. PATIENTS AND METHODS: Following vitrectomy and silicone oil injection, 16 eyes of 16 consecutive patients undergoing phacoemulsification and IOL implantation were included in the study. RESULTS: The mean age of patients was 58.3 +/- 9.2 years (range, 38 to 71 years). The time interval between the cataract surgery and silicone oil injection was 5.8 +/- 1.7 months (range, 4 to 9 months). The mean number of previous surgeries was 2.0 +/- 0.8 (range, 1 to 4). Trypan blue (0.4%) was used for anterior capsule staining in 3 eyes with white cataract. Dispersive viscoelastic material was used during all steps of phacoemulsification. A capsular tension ring was inserted after capsulorhexis and hydrodissection in all cases. An IOL with a 6.0-mm optic was implanted in all eyes. The preoperative best-corrected visual acuity ranged from hand motions to 0.3. The mean postoperative best-corrected visual acuity was 0.3 +/- 0.1 (range, 0.1 to 0.6); best-corrected visual acuity increased in all eyes. A small amount of silicone oil moved into the anterior chamber during phacoemulsification in 1 eye and was evacuated. In all eyes, no silicone oil was present in the anterior chamber postoperatively. CONCLUSION: The use of dispersive viscoelastic and a capsular tension ring provides safer phacoemulsification and foldable IOL implantation in eyes already filled with silicone oil.

Adult↗
PubMed1992

[Removal of silicone oil in treatment of so-called emulsification glaucoma].

We investigated whether emulsification glaucoma after silicone oil implantation can be influenced positively by removal of the oil. In 16 of 264 patients successfully operated upon with purified silicone oil 5000 cps, we found a glaucoma refractory to medical therapy and probably caused by emulsification. We removed the silicone oil from these eyes and followed them up for a period of 6 months (12.5 +/- 7.3 months). In 12 of the 16 eyes, the intraocular pressures were normalized after silicone oil removal with or without antiglaucomatous therapy. Four eyes showed raised intraocular pressures in spite of silicone oil removal. These could, however, be largely explained by neovascularization or chronic inflammation with increasing anterior synechia formation. In eyes with possible emulsification glaucoma, early and thorough removal of the silicone oil is therefore recommended since this can result in normalization of intraocular pressures in a large percentage of cases.

Glaucoma↗
PubMedDate not supplied

A survey of disinfection of irreversible hydrocolloid and silicone impressions in European Union dental schools: epidemiologic study.

PURPOSE: The objective of this cross-sectional study was to describe corresponding procedures for irreversible hydrocolloid and silicone impressions taught and used in European Union dental schools. MATERIALS AND METHODS: A self-administered questionnaire requesting information about rinsing and disinfection methods was sent to each of the 373 heads of prosthodontic, pedodontic, and orthodontic departments in the 131 European Union dental schools. Response rate was 94%. Statistical analysis included chi-square or Fisher exact tests, and ANOVA or Kruskall-Wallis tests. RESULTS: Of the responding departments, 92% systematically rinsed their impressions. Fifteen percent of the departments, mostly orthodontics, never disinfected irreversible hydrocolloid impressions, and 11% never disinfected silicone impressions. The immersion method was used by 65% for irreversible hydrocolloid impressions (73% for silicone), with a disinfection time of 10.3 +/- 6.3 minutes (11.8 +/- 7.4 for silicone). The disinfected impressions were not rinsed by 16% for irreversible hydrocolloid and 14% for silicone. Most departments used brand-name products. CONCLUSION: The same disinfection procedure for both irreversible hydrocolloid and silicone impressions was used by 78% of departments. There was great diversity, however, between departments in the procedure used for each impression material.

Alginates↗
PubMed2005

[The effect of bicanalicular silicone tube implantation on the success rate of endoscopic dacryocystorhinostomy].

OBJECTIVES: We evaluated operative success rates of endoscopic dacryocystorhinostomy with or without bicanalicular silicone tube implantation. PATIENTS AND METHODS: Twenty-six eyes of 24 patients with simple epiphora (23 eyes) or chronic dacryocystitis (3 eyes) were treated by endoscopic dacryocystorhinostomy with (18 eyes) or without (8 eyes) bicanalicular silicone tube implantation. In the implantation group, one patient underwent endoscopic sinus surgery and two patients underwent submucosal resection. The silicone tubes were removed after a mean of 4.48 months (range 7 days to 6 months). The mean follow-up period was 12.4 months. RESULTS: During the follow-up period, no significant differences were found between the two treatment groups with respect to the occurrence of epiphora. It disappeared in 17 eyes (94.5%) and in six eyes (75%) with or without silicone tube implantation, respectively. Operative success rates were significantly different between patients with simple epiphora (95.7%) and chronic dacryocystitis (33.3%). The only complication was a punctual damage seen in one patient. CONCLUSION: The lack of a significantly high influence on the success rate, increased operative cost, and the risk for complications due to silicone tube insertions may be considered disadvantages of bicanalicular silicone tube implantation.

Adult↗
PubMed2006

[Effect of application of silicon on arsenic uptake by rice seedlings in soil].

The objective of study was to investigate effect of silicon on arsenic uptake by rice seedlings in two soils with different arsenic concentrations. The results show that the addition of silicon has little effect on shoot and root dry weights of rice seedlings. The addition of silicon did not affect shoot and root P concentrations of rice seedlings grown in low arsenic soil, but significantly increased shoot P concentrations on rice grown in high arsenic soil. Irrespective of the initial pH of K2SiO3 solution, the addition of silicon significantly decreased shoot and root As concentrations of rice seedlings compared with the control. For seedlings grown in low As-contaminated soil, As concentrations in shoot and root were reduced by 36%-59% and 15%-37% with the application of silicon, respectively. For seedlings grown in high As-contaminated soil, As concentrations in shoot and root were reduced by 42%-58% and 70%-82% with the application of silicon, respectively. These results are in agreement with our previous reports based on a solution culture experiment. Possible mechanisms of the effect of Si on As uptake was also discussed.

Absorption↗
PubMed2005

[Risk factors of retinal redetachment after expected silicone oil removal].

PURPOSE: To analyze the clinical risk factors of the occurrence of retinal redetachment after expected silicone oil removal. METHODS: Clinical data were studied retrospectively. A total of 105 eyes of 104 consecutive patients were enrolled according to the criteria as follows: the expected intraocular silicone oil removal was performed after pars plana vitrectomy for complicated rhegmatogenous retinal detachment (RRD); the retina was flat during silicone oil tampanade; the patients were dealt with by the same surgeon. RESULTS: With a mean postoperative follow-up of 310 days, 11 of 105 eyes (10.4%) developed retinal redetachment after silicone oil removal. The redetachment rate was higher in the aphakic eyes (21.1%) than in the phakic/pseudophakic eyes (4.5%) (OR 5.69, P < 0.05). However, the factors, including giant tear, PVR grade C3 and D, previous failed retinal detachment surgery, high myopia, had no significance with retinal redetachment (Ps > 0.05). Among the 77 eyes undergoing prophylactic 360 degree laser retinopexy before silicone oil removal, 4 eyes had retinal redetachment (5.2%). The redetachment ratio was lower than those without prophylactic laser retinopexy (OR 0.16, P < 0.05). CONCLUSION: Aphakia is a risk factor of retinal detachment after removal of silicone oil. Prophylactic 360 degree laser retinopexy can reduce the incidence of retinal redetachment.

Adolescent↗
PubMed1991

[Visual outcome after silicon oil surgery].

The question as to whether silicone oil is toxic to the retina has not been resolved to this day. We have attempted to find evidence of retinal toxicity by studying the development of visual acuity in eyes operated on with silicone oil. We selected these eyes from a cohort of about 500 that had attached retina, no glaucoma and no keratopathy. The average visual acuity increased continuously over 2 years if all extraretinal factors influencing visual acuity are excluded. Although in eyes from which silicone oil had been removed visual function developed better than in those in which it remained indefinitely, this could not be attributed to a toxic effect of silicone oil, since the difference was apparent even while eyes in both cohorts where still filled with oil. The difference is more probably a result of patient selection. In individual cases in which silicone oil was not removed for up to 8 years the visual acuity remained stable. An analysis of the patients with loss of vision despite attached retinas yielded causes that were essentially specific to the underlying disease. We found no clinical evidence suggestive of a toxic effect of silicone oil.

Follow-Up Studies↗
PubMed1989

[Keratopathy following vitrectomy with silicone oil injection].

We present a retrospective study on keratopathy following vitrectomy and injection of SF96 silicone oil (viscosity 1000 centipoise, n = 232 eyes) and the purified OP 1000 silicone oil (viscosity 1000 centipoise, n = 129 eyes). In cases with aniridia, with closed inferior basal iridectomy (IBI) or without IBI, keratopathy was found in 74 of the 166 eyes (45%) injected with silicone SF96 and in 14 of the 30 eyes (47%) injected with silicone OP 1000. An intact IBI reduced the incidence of keratopathy to 0% (SF96, 0/45 eyes) or 6% (OP1000, 5/88 eyes) when the anterior chamber was free of silicone. When silicone oil was in contact with the corneal endothelium (due to periretinal reproliferation, hypotony, overfilling or droplet formation), there was corneal decompensation in 66% (SF96, 14/21 eyes) or 55% (OP1000, 6/11 eyes). The keratopathy presents as calcified band keratopathy or diffuse bullous corneal edema as in "endothelial decompensation." These variations in keratopathy are in agreement with the following basic diagnoses: 77% (43/56 eyes) of trauma patients (n = 130) develop calcified band keratopathy, and 47% (24/51 eyes) of patients with idiopathic proliferative vitreoretinopathy (n = 182) present with diffuse bullous corneal edema.

Cornea↗
PubMed1989

[Silicone breast implants].

A brief review of the use of silicone breast implants, their structure, methods of implantation and complications is presented. Acute complications are rare, being mainly infection and hematoma. Long-term complications, on the contrary, are common, consisting mainly of capsular contracture around the prosthesis with subsequent pain and deformation of the breast. More rarely silicone granulomas form, and prosthesis rupture or herniation occurs. The importance of silicone leakage for these complications is discussed separately as well as the treatment of and prevention of capsular contracture and demonstration of silicone in tissue. A critical attitude towards the use of silicone breast implants, when these are used for purely cosmetic purposes, is recommended at present. New improved types of silicone breast implants are currently being tested clinically.

Breast↗
PubMed1979

[Liquid silicones in reconstructive surgery of the tendons. Experimental studies].

The results of reconstruction of flexor tendons of the hand are not satisfactory despite many operative methods. Since 70 years different surgical methods were described from which only some found application and some are tested up to day. The classical surgical methods do not prevent adhesions of tendons to the surrounding tissues. Therefore studies were undertaken to proof the usefullnes and the specific properties of silicone fluids in the reconstructive tendon surgery. Examinations were done on 48 mongrel rabbits of both sexes on surgically exposed tendon of the gastrocnemius muscle. The animals were divided into two groups. In group I the tendon of the right extremity was covered with Medical Fluid 360, and in group II - with Silol F 350. Each group was divided into two subgroups. In subgroups IA and IIA the tendinous sheath was removed whereas in subgroups IB and IIB the tendon was also cut and sutured. The silicone fluids were spread in amount up to 1 ccm, and uniform coat on tendon surface resulted. On the left tendons 0.9% natrium chloride solution was spread for control. In both groups the dissections were performed 14, 30, 90, 180 days after the operation. The following criteria were applied to evaluate the results: - the appearance of extremities, the range of motility in knee and ankle joint, wound healing, - the macroscopic appearance of isolated tendons, - the degree of excursion measured in millimeters, - the appearance and degree of adhesion between the tendon and surrounding tissues. 800 histological preparations were made. They were evaluated in biological microscope with special attention to the dimension of tissue reaction. In histological examinations the differences in tissue reaction were stated between subgroups A and B of both groups. However, no differences were found dependent from the applied silicone in groups I and II. In the early period, around the siliconized tendon poorly cellular, not significant exudative reaction was found. This reaction changed afterwards into proliferative one, which led to the development of a new tendon sheath. These changes did not discriminate distinctly the flexibility of the examined tendon. After applying 0.9% natrium chloride solution to uncovered tendon (control), adhesions of the tendon to surroundings were observed, which resulted in discrimination of tendon's flexibility. It was proved that silicone fluids applied to the sutured tendon (groups IB and IIB) did not handicap the healing process. The peritendinous adhesions were more intensive around the tendon's anastomosis than in the remaining tendon part. These adhesions were significantly smaller in comparison with the control extremities whose tendons were covered by0.9% natrium chloride solution. The application of small quantity of silicone fluids according to both up to day and own investigations do not cause local or general pathological changes...

Achilles Tendon↗
PubMed1983

Silicone as coating material for hemoperfusion.

The effectiveness of activated charcoal in direct hemoperfusion (DHP) has been recognized, but there are still problems with a decrease in solid components of blood and of dimishing adsorption capacity by coating layers on the surface of the sorbents in DHP. In the present study, we have developed activated charcoal derived from thermosetting resin, coated with silicone, and have observed changes in blood components after a 3 hr DHP. Adsorption capacity of the activated charcoal was determined in vitro, and was compared with noncoated charcoal and poly(hydroxyethyl methacrylate) (PHEMA) coated charcoal. Reduction in leukocyte and platelet counts was less with the silicone coated and PHEMA coated charcoals than with the noncoated charcoal. Variations in leukocyte counts and platelet counts were less in DHP with silicone-coated charcoal than with the others. Adsorption of the solid components of blood on the silicone-coated charcoal, examined by scanning electron microscopy after DHP, was very slight, showing its excellent applicability to DHP therapy. The degree of adsorption of various amino acids and related compounds on the silicone-coated charcoal was comparable to that on the noncoated charcoal. Thus, there seems only slight reduction in the degree of adsorption on the silicone-coated charcoal.

Adsorption↗
PubMed1995

Thyroplasty using a silicone elastomer implant.

Silicone has been used in a variety of forms as a replacement for soft tissue for more than three decades in the United States. The safety of this practice has come under scrutiny recently as our knowledge of the local, systemic, and immune effects of silicone has expanded. Contrary to what was once thought, silicone is not biologically inert. Silicone elastomer, however, has not been implicated in the development of systemic immune disease or carcinogenesis. The evidence to date supports the continued use of silicone elastomer implants in the larynx. It is clear, however, that continued investigation into the basic biologic properties and mechanisms of the host-silicone implant interaction is warranted.

Humans↗
PubMed1995

[Development of protective antituberculosis immunity after BCG vaccination in mice with silicon deficiency in water and feed].

An experimental mouse model of normal and deficient content of silicon in the diet in CBA strain has been developed. It is shown that after BCG vaccination silicon deficiency brought about a dramatic decrease of in vitro proliferation of splenic lymphocytes in the presence of mycobacterial antigens, ConA or in the absence of the stimuli. DTH response to tuberculin in silicon deficient mice was also reduced. The level of specific serum IgG did not depend upon silicon content in the diet. The addition of silicon into the diet of silicon-deficient mice beginning from BCG vaccination restored the level of immune reactions.

Animal Feed↗
PubMed1995

Silicone breast implant-associated scarring dystrophy of the arm.

BACKGROUND: Breast implants have been known to rupture after trauma or closed capsulotomy with spread of the gel down the arm or abdominal wall. Nodular foreign-body granulomatous reactions have been reported in these cases. We report the unique occurrence of significant overlying scarring and ulceration following silicone gel migration down the affected arm. OBSERVATIONS: A 47-year-old woman experienced rupture of her right silicone gel implant with migration of the silicone down her arm 10 years before our examination. Skin changes with atrophic hidebound scarring and ulceration slowly progressed over the last 7 years. Radiographs and magnetic resonance imaging scans demonstrated material consistent with silicone in the soft tissues. CONCLUSIONS: Silicone is not an inert substance and can rarely result in devastating local tissue destruction where migration has occurred. The possibility of significant silicone gel migration should be considered during evaluation of patients with ruptured implants.

Arm↗
PubMed1994

Retinal hemodynamics after pars plana vitrectomy with silicone oil tamponade.

Pars plana vitrectomy with silicone-oil tamponade is frequently performed in cases of complicated retinal detachment. Because of the lower specific gravity and the lower surface tension of silicone oil in comparison with the aqueous phase of the vitreous, an influence on the blood flow in the retinal vessels would be expected. However, not only the silicone oil but also the operative trauma and a buckling procedure may have an influence on the retinal blood flow. To examine this question we measured the arteriovenous passage time in the silicone-oil-filled eye and in the contralateral eye in 14 cases using a laser scan ophthalmoscope at 3-5 days after surgery. The arteriovenous passage time is a parameter for the retinal microicirculation. In all cases we found a prolonged arteriovenous passage time in the silicone-oil-filled eye in comparison with the contralateral eye (mean value +/- SD, 2.5 +/- 0.8 vs 1.25 +/- 0.25 s; P < 0.01). The prolongation of arteriovenous passage times observed in silicone-oil-filled eyes indicates that the microcirculation is worsened at least during the early postoperative period.

Adult↗
PubMed1993

[Problems with silicon oil removal. A study of 63 consecutive cases].

Silicone oil is used in the treatment of complex retinal detachments, but late complications have been reported by many authors. Silicone oil removal (SOR) is therefore performed in order to reduce these complications. SOR was investigated in 63 consecutive cases. All these eyes had had a totally attached retina for at least 3 months before SOR was performed, there were no signs of traction or reproliferation, and the minimum vision was 4/200. The duration of silicone oil tamponade was less than 6 months in 13 eyes, 6-12 months in 18 and more than 1 year in 32 eyes. In post-traumatic and diabetic cases it was possible to remove silicone oil after 8 to 10 months and in PVR cases after 14 months. Redetachment of the retina was the most frequent complication of SOR, appearing in 18/63 eyes; 16 of them were refilled. In 9 eyes, the visual acuity present before silicone oil removal was reestablished. The redetachment rate was similar in PVR, diabetes and trauma cases and had no correlation with the duration of silicone oil tamponade. Increased intraocular pressure was observed in 13 eyes before SOR but it returned to normal levels afterwards in 8 cases without further surgery. The results of our study show that even if the indication is established very carefully, SOR results in a relatively high rate of complications, such as redetachment of the retina. Therefore every case undergoing this procedure must be evaluated in detail.

Adolescent↗
PubMed1993

Enhanced activity of lysosomal beta-galactosidase after silicone implantation: an experimental study in rats.

Biologic consequences of silicone implantation may include changes in host connective tissue metabolism. Lysosomal beta-galactosidase (beta-GAL) activity, which is a sensitive marker of fibrotic diseases and may be a useful marker of collagen turnover, was examined in the serum of rats with implanted silicones. No significant difference in spectrofluorometrically determined enzyme activity was demonstrated in rats subjected to dorsal submuscular pocket dissection without implantation and corresponding nonoperative controls. Rats with implanted solid silicone elastomer or free polydimethylsiloxane gel (both components obtained from mammary implant) revealed enhanced activity of serum beta-GAL. Higher enzyme activity was observed in animals with implanted silicone gel with a peak level of 2.73 +/- 0.08 pmol/30 min/ml 16 weeks after implantation. Increased collagen deposition and capsular thickness was demonstrated around implanted gel material as compared with that around elastomer shell. Animals with implanted absorbable and nonabsorbable materials, polyglactin and Teflon (polytetrafluoroethylene), respectively, after initial increase of beta-GAL activity demonstrated enzyme activity within the normal range. Findings indicate that there is enhanced lysosomal beta-GAL activity after silicone implantation in rats. Clinical relevance and its possible significance as a predictor or indicator of local or systemic fibrosis after silicone implantation seems worthy of further investigation.

Animals↗