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At least 1,153 records · Page 64Linked to original sources
PubMed1977

Results of silicone oil injection in massive preretinal retraction.

A series of 69 eyes in which silicone oil injection was used to treat retinal detachment with massive preretinal retraction was reviewed with respect to retinal re-attachment and visual function. The selection of patients for treatment with silicone oil injection was influenced by the poor prognosis with conventional methods, the high incidence of postoperative complications after silicone oil injection, and the prognosis of the fellow eye. Although silicone oil injection is not an ideal method of re-attaching the retina, it remains the only successful method in many cases of massive preretinal traction. In cases in which the fellow eye is defective or is at risk of becoming so, we believe that the injection of silicone oil is fully justified.

Adolescent↗
PubMed1987

Silicone-induced hypercalcaemia in haemodialysis patients.

Silicone spallation from the roller-pump insert in dialysis blood lines leads to the accumulation of silicone in haemodialysis patients, which in turn leads to a foreign-body reaction with granuloma formation. We have studied two patients in whom documented silicone accumulation has been associated with both granuloma formation and significant, persistent hypercalcaemia. In both patients plasma levels of immunoreactive parathyroid hormone and 1,25-dihydroxyvitamin D were low or undetectable. In one patient, hypercalcaemia responded only partially to corticosteroids, but completely to naproxen. Both patients were changed to silicone-free blood lines and their hypercalcaemia subsequently resolved. The results indicate that in some haemodialysis patients, silicone accumulation and granuloma formation may lead to hypercalcaemia that is independent of 1,25-dihydroxyvitamin D, and that may instead reflect altered prostaglandin metabolism.

Adult↗
PubMed1988

Massive injection of liquid silicone for hemifacial atrophy.

Liquid silicone injection for soft-tissue augmentation remains a controversial procedure despite 30 years of clinical use which has demonstrated exceptional results in patients with severe facial atrophies. This article describes a case in which massive silicone injection was used to treat hemifacial atrophy. Over a 9-year period, 11 injections totaling 97 ml of liquid silicone were administered to the patient, representing the largest volume of silicone ever injected into the face. In the 16 years following the first injection, there have been no major complications and the patient has experienced a greatly enhanced body image and improved self-esteem. Although liquid silicone for injection remains under investigation, its use in patients with hemifacial atrophy may produce dramatic results with minimal complications.

Adolescent↗
PubMedDate not supplied

Preservation of compliance in a small diameter microporous, silicone rubber vascular prosthesis.

Compliance is believed to be a significant factor in maintaining the patency of small diameter vascular grafts. This study evaluated the compliance changes with time of microporous Replamineform silicone rubber prostheses. The compliance of 15 canine femoral artery interpositions (4 mm internal diameter X 6 cm length) was measured by in-vivo electromagnetic rheoangiometry immediately following implantation and at intervals to eight months. At implantation, silicone rubber grafts were overcompliant (15.0 +/- 1.1% radial change/mmHg X 10(-2); mean +/- S.E.) compared to the proximal artery (7.7 +/- .6%). The compliance of the prostheses decreased within two weeks (6.3 +/- .9%) and remained isocompliant to the proximal artery for eight months. The compliance determinations for the silicone rubber grafts were compared with those from PTFE prostheses and vein grafts acquired by the same method in a previous study. The analysis demonstrates the preservation of isocompliance of the silicone rubber prostheses compared to the native arteries. In contrast, the minimally compliant vein grafts and PTFE prostheses continued to decrease in compliance following implantation. This microporous silicone rubber graft may improve the success of small internal diameter arterial reconstructions by eliminating failures caused by compliance mismatch between the artery and the prosthesis.

Animals↗
PubMed1986

[A new superselective balloon catheter--all-silicone catheter with a floppy tip].

We have introduced concept of "chemical" embolization and have tried to develop a new agent which would enable us to embolize the lesion with one-shot injection. Such an agent must be able to occlude diffusely the lesion distal to the catheter. This has made it mandatory to develop a new catheter which can be introduced into the vessel as close to the lesion as possible with fewer risks of clot formation and/or vessel damage. A new superselective balloon catheter for angiography and infusion of liquid embolizing materials has been developed. This catheter consists of a proximal relatively stiff silicone catheter, a short distal thin-walled flexible silicone catheter and silicone balloon. These three silicone components are connected by silicone adhesives. The distal catheter allows us to catheterize fine arteries such as lenticulostriates, while the proximal catheter assures easy manipulation. This balloon catheter can be used for superselective angiography and infusion of liquid embolizing materials. It has been used on nine patients; one with a dural arterio-venous malformation (AVM), four with meningiomas, and four with brain and spinal cord AVMs. In the case of dural AVM and meningiomas, it was possible to easily introduce into the middle meningeal artery distal to the foramen spinosum. In addition, in one of the cases of meningioma, we were able to catheterize one of the main feeding pedicles beyond the pterion. Chemical embolization was carried out in 5 cases with good results. In the case of brain and spinal cord AVM, useful information was obtained from the superselective angiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1985

Silicon metabolism: the basic facts in renal failure.

Silicon levels in plasma and urine have been studied in normal subjects, in chronic renal failure patients, and in regular hemodialysis patients. Plasma levels were elevated in chronic renal failure, and in hemodialysis patients they were three times the control values. Urine silicon excretion is significantly related to creatinine clearance, and to urinary omolality, magnesium and calcium levels. A small amount of residual silicon is found in the hollow fiber artificial kidneys made by some manufacturers. High concentrations of silicon are found in commercial dialysate and pass down a chemical concentration gradient into the blood compartment. It is concluded that silicon is sequestered rapidly in the body during hemodialysis, and that this amounts to 58 g of silicic acid per annum from hemodialysis alone.

Humans↗
PubMed1979

[Experimental and clinical experiences with silicone catheters in fistulizing glaucoma surgery].

1. A historical revue of seton operations is presented, which were actually explored for the first time by Rollet in 1907. 2. The paramount importance of the selection of the appropriate material for the setons is stressed. 3. Ocular tolerance especially of silicone tubings has been investigated by animal experiments. Excellent tolerance of silicone intraocularly as well as subconjunctivally has been found. This fact confirms experimental investigations by other authors. 4. In animal experiments for the first time a surgical technique securing firm anchorage of a sole silicone tubing could be developed. Insertion of a silicone catheter was combined with thermal sclerostomy; ocular hypotony was not encountered. 5. A study exploring aqueous egress following the new surgical procedure has been conducted by means of injection of fluorescein into the anterior chamber. Various exit-sites of aqueous were recorded: diffuse outflow through the filtration cleft as well as the catheter lumen, and also via channels either within lymph vessels or secondary aqueous veins. 6. Aqueous outflow following the seton operation has also been studied by scintigraphic means; the first description of this method in glaucoma-operated eyes is presented. Applying this technique not only the existence of a filtering bleb is documented, but in addition the speed of aqueous transit through the filtering bleb was measured. This transit has been found to be a rapid one. 7. The clinical results of this type of seton operation do confirm the experimental evidence of excellent ocular tolerance of silicone tubings as well as the reliability of their firm anchorage. Postoperative tension with or without additional antiglaucomatous medication proved quite satisfactory. 8. The proposed surgical procedure is recommendable especially in patients exhibiting haemorrhagic glaucoma, were conventional methods are likely to fail in the majority of cases.

Adult↗
PubMed1985

Reduction of silicone particle release during haemodialysis.

Spallation of silicone was evaluated in an in vitro system, using a commercial blood pump and dialysis tubing. Silicone particle release was assessed at various occlusion forces (5.5-22 kp). When the occlusion force was reduced from 22 to 5.5 kp, the number of released silicone particles decreased by approximately 80 per cent; in parallel, the amount of silicone retrieved from the recirculation fluid decreased from 1.6mg to less than 0.23mg. It is concluded that reduction of occlusion pressure within the blood pump effectively reduces spallation of silicone tubing.

In Vitro Techniques↗
PubMed1985

X-ray microanalysis of uremic nephrocalcinosis: cellular distribution of calcium, aluminium and silicon in uremic nephrocalcinosis.

Nephrocalcinosis with a deposition of aluminum and silicon has been previously reported in uremic rats. To clarify the origin of these elements thin sections of renal cortex were examined by means of electron microscopy and energy dispersive x-ray microanalysis. Studies were performed on subtotally nephrectomized rats (SNX) and sham-operated control animals. Electron microscopy of proximal tubular epithelial cells in SNX rats unlike control rats revealed severe mitochondrial disorganization; irregularity of the tubular basement membrane which exhibited various inclusions; and lamellar bodies within the brush border membrane. On x-ray microanalysis disorganized mitochondria contained calcium and silicon, while secondary lysosomes displayed aluminum and silicon. The tubular basement membrane of SNX rats, as well as lamellar body-like inclusions within the brush border contained calcium, aluminum and silicon together. It is suggested that lysosomal and mitochondrial interaction in proximal tubular cells of uremic rats may contribute to the deposition of calcium together with aluminum and silicon in the renal parenchyma, resulting in nephrocalcinosis.

Aluminum↗
PubMed1983

[Silicone deposits in macrophages of patients on chronic hemodialysis].

A retrospective study was carried out in search of silicone deposits in 11 periodic hemodialysis patients (1 liver biopsy, 4 splenectomies and 6 autopsies) treated between 12 and 60 months with equipment containing a silicone pump segment. Silicone particles were found in the macrophage cells of all patients, especially in the liver and spleen, but also in lymph nodes, bone marrow and even an artery wall. In some cases, macrophage response had formed sarcoid-like granulomas. Silicone deposits in 3 patients were associated with a hypersplenism syndrome totally or partially improved by splenectomy. No relationship could be established between foreign material in the liver and clinical or biological abnormalities. Three patients who had died subsequent to peritoneal dialysis or hemodialysis involving polyvinyl chloride materials served as controls. No silicone inclusions were found in their tissues at autopsy.

Adult↗
PubMed1978

Intravitreal silicone injection.

A clinico-pathological report is presented of a case of intravitreal silicone injection in which the eye had to be enucleated 7 years later. Numbers of highly refractile silicone particles of various size were found in all the ocular tissues except the sclera. A great number of silicone cavities were present in most tissues, and many contained silicone globules. The presence of silicone within the lens was confirmed by electron microscopy.

Adult↗
PubMed1984

Silicone implants in dogs. A ten-year histopathologic study.

The biocompatibility of implanted materials is important to the successful long-term results obtained in reconstructive surgery with these materials. Recently, interest has emerged regarding host response to the wear debris of implanted material. Since 1962 flexible implant materials have been studied in the Orthopaedic Research Department at Blodgett Memorial Medical Center. An important aspect of this study has been a concern for host tolerance and the evaluation of biologic responses to implanted silicone elastomer. Three dogs in which implants of silicone elastomer had been in place for more than ten years were carefully studied by complete autopsy. A benign foreign-body giant cell response to local silicone wear debris was observed. No silicone particles or macrophage giant cell reactions were found in any distant organs. The host response to silicone wear debris was benign, and no adverse systemic influences were noted.

Amputation Stumps↗
PubMed1983

Hysteroscopic tubal occlusion with silicone rubber.

A new method of sterilization for women is being investigated in several outpatient centers. The technique involves flowing liquid silicone rubber into the fallopian tubes. The silicone cures in place and forms a rubbery solid plug. The catalyzed liquid silicone is pumped through a special polysulfone guide assembly that fits through the operating channel of a standard hysteroscope. On the end of the guide is a hollow premolded silicone rubber tip that fits into the cornual ostium of the tube. When the silicone cures it also cross-links to this tip so that the tip becomes part of the plug. Results as of April 1, 1982, from 350 women in the Philadelphia center suggest that proper plug formation prevents pregnancy and that the method can be applied to about 85% of properly selected women.

Fallopian Tubes↗
PubMed1982

Positive identification of silicone in human mammary capsular tissue.

A specific quantitative assay was developed to determine silicone concentrations in contracted mammary capsular tissue. The concentrations of silicone in tissues from 14 patients with gel-filled implants varied from 15 to 9800 micrograms polydimethylsiloxane per gram of tissue. This silicone is probably a high-molecular-weight polymer that has diffused through the implant envelope. Samples from a patient with saline-filled implants contained no silicone. The concentration of silicone was not related to capsule age. The polymer in these tissues appeared to be unaltered, in that no evidence of metabolic products was found.

Breast↗
PubMed1995

Malar augmentation with silicone implants.

This study is a retrospective review of all consecutive surgeries involving insertion of silicone malar implants performed at the Manhattan Eye, Ear and Throat Hospital from January 1, 1985 to April 30, 1993. Sixty-four patients underwent placement of 126 silicone malar implants. Three different sizes were utilized: 23 size 1, 85 size 2, and 18 size 3. Eleven patients underwent unilateral implant placement, all for reconstructive purposes. The average and median ages of the patients were 43 and 44 years, respectively, with a range of 18 to 83 years. Malar implants were inserted for the following reasons: hypoplasia, post-traumatic deformity, post-tumor resection deformity, and correction of hemifacial microsomia. In 79 percent of the patients, malar augmentation was performed in conjunction with other surgical procedures. All implants were placed in a subperiosteal pocket by either the intraoral, subciliary, or preauricular approach. Forty-one percent were fixed in place by percutaneous sutures. Malar augmentation with silicone implants for both aesthetic and reconstructive purposes is an increasingly common surgical procedure. Good results are obtained with few complications. Infection is rare even with transoral placement. Silicone malar implants should be placed in a subperiosteal pocket and can be inserted safely through various routes. Malpositioning of implants is infrequent, and fixation sutures are not required. The most common problem is improper size selection. Patient satisfaction is high, in that no patient underwent permanent removal of a malar silicone implant once inserted.

Adolescent↗
PubMed1995

Inferior peripheral iridectomy in patients receiving silicone oil. Rates of postoperative closure and effect on oil position.

BACKGROUND: Silicone oil tamponade is used in treating retinal detachments, but silicone-associated complications remain frequent. Keratopathy and acute pupillary block glaucoma are related to migration of silicone oil into the anterior chamber. Since 1985, many surgeons have created an inferior peripheral iridectomy (PI) at the time of surgery to prevent forward migration of the oil, but the rate of postoperative closure of the PI and the effect on oil position have not been well defined. METHODS: The charts of 292 patients undergoing silicone oil surgery were reviewed. The status of the PI and the oil position were determined throughout the postoperative period. RESULTS: Postoperative closure of the PI occurred in 40 (33%) of 121 aphakic eyes in the early postoperative period. Forward migration of the oil was highly associated with closure of the PI (32/40, 80%). Conversely, forward oil migration occurred in only 11% (9/81) of eyes with patent PIs. The rate of PI closure was significantly greater for patients with proliferative diabetic retinopathy (21/40, 52%) than for patients with proliferative vitreoretinopathy (11/58, 19%). CONCLUSION: Postoperative closure of the PI occurred in a significant fraction of eyes undergoing silicone oil surgery, was highly correlated with forward oil migration, and occurred most frequently in eyes with proliferative diabetic retinopathy.

Corneal Diseases↗
PubMed1994

[Silicone implants and breast cancer: real or fictitious problem? A case report and review of the literature].

We present a case of breast cancer 9 years after subcutaneous mastectomy for bilateral phylloid tumor with silicone implants. The patient had a stage III adenocarcinoma (T4 N1 M0) at diagnosis; a modified radical mastectomy was done, followed by radiotherapy and chemotherapy. Later on, Tamoxifen was prescribed (positive hormone receptors). Reviewing the literature about this subject in a context of a moratorium of the Food and Drug Administration (FDA) in the United States recommending suspension of silicone breast implantation, we can propose several conclusions: Previous and recent studies did not show any direct relation between cancer and silicone implants for augmentation mammoplasty; on the contrary, a lower incidence of breast cancer is noted. Breast cancer incidence with silicone implants seems to be higher with reconstructive mammoplasty after mastectomy for benign disease (fibrocystic disease, dysplasia, phylloid tumor), or prophylactic reason, or malignancy (carcinoma in situ, lobular and multifocal carcinoma, early breast cancer...). This can be related to recurrence or cancer development on residual breast tissue. Breast cancer with silicone implants is of poorer prognosis because of the later diagnosis of the disease.

Adenocarcinoma↗
PubMed1995

Serum antinuclear antibodies in women with silicone breast implants.

OBJECTIVE: Recent evidence suggests that immunologic abnormalities are not uncommon in individuals with silicone breast implants. The purpose of our study was to evaluate in a consecutive manner, the prevalence of autoimmunity as assessed by the presence of antinuclear antibodies in a larger number of patients with silicone breast implants. METHODS: Antinuclear antibody (ANA) testing using an indirect immunofluorescence technique was performed on 813 individuals with silicone breast implants. All subjects except for 3 transsexual males, were female. The overwhelming majority, over 99%, were white. The average age of the subjects was 46.2, with a range of 17 to 72 years. RESULTS: ANA positivity was found in 244 of 813 individuals (30%) using a mouse kidney substrate; and in 470 of 813 (57.8%) using a HEp-2 cell line. The most common immunofluorescent pattern found using HEp-2 was speckled, present in 341 (72.5%) individuals, followed by homogeneous pattern in 113 (24%), nucleolar in 63 (13.4%), and 5 (1.06%) were anticentromere. Anti-dsDNA antibodies measured by an ELISA assay were found in 6 of 71 patients (8%). Rheumatoid factor and C-reactive protein were found above healthy controls in less than 10% of cases studied. The high prevalence of ANA found in patients with silicone breast implants agrees with similar observations by others. The finding of anticentromere and nucleolar patterns has great interest and relevance. These fairly distinct ANA patterns are most commonly seen in the idiopathic form of scleroderma and related conditions. CONCLUSION: These findings suggest that ANA positivity is relatively common in individuals with silicone breast implants, and may support the existence of autoimmune mechanisms in the pathogenesis of the clinical manifestations seen in this population.

Adolescent↗