Frequently used extraoral maxillofacial prosthetic materials and their longevity - A comprehensive review

The longevity of an extraoral prosthesis depends on its physical and mechanical properties and user maintenance. Faced with multiple outcome measures, researchers find it difficult to determine the most appropriate extraoral prosthetic material. This comprehensive review evaluates the most used extraoral prosthesis materials and qualitatively assesses their longevity and function. The study aims to identify and interpret the results of current updates on the factors that affect longevity and functionality. This comprehensive review summarizes and evaluates differences in the properties of commonly used extraoral maxillofacial prosthetic materials. The review was planned to focus on all factors related to the longevity and function of the extraoral maxillofacial prosthetics. An electronic search covered English articles in PubMed, Scopus, Google Scholar, Web of Science, and grey literature. Manual searching was also performed. Six authors participated in the screening. Search engines extracted 1107 records, and 88 studies were included for qualitative and bias assessments. Silicones are the most frequently used extraoral maxillofacial prosthetic materials. Heat-cured silicones are more color-stable than those cured at room temperature. Additional ingredients and processing techniques affect prosthesis longevity.

In Situ Casting of Platelet Rich Plasma/SiO2/Alginate for Bone Tissue Engineering Application in Rabbit Mandible Defect Model

Statement of the Problem

The administration of both platelet rich plasma (PRP) and silicon dioxide (SiO₂) to the bone defects accelerates bone repair and regeneration. Appli-cation of both of them may show synergistic regenerative effects.

Purpose

Our objective was to evaluate the possible synergistic osteogenic effects of PRP and SiO₂ by injecting them using an ad hoc device.

Materials and Method

In this experimental study, PRP/SiO₂ scaffolds were fabricated by in situ casting method with the help of CaCl₂ as the gelation factor and alginate as the stroma; and then, the biodegradability and spatial arrangement were assessed. The injecta-ble scaffold was introduced into the 40 rabbit mandibular defects by an ad hoc two-channel injecting device. Five defects received PRP/SiO₂/alginate as the treatment; the other sets of defects were treated by PRP/alginate, SiO₂/alginate, and the last five defects served as the control groups by getting only alginate injections. The osteogenicity of the scaffolds was evaluated by radiological and histological procedures; they were then compared with each other. Analysis of variance and least significant difference tests were used to analyze the data.

Results

The SiO₂-treated group showed a significant higher bone area compared to PRP/ SiO₂-treated groups on day 40 (p= 0.013). The number of osteocytes was higher in SiO₂-treated than the control groups on both 20 and 40 days (p= 0.032 and 0.022, respectively). The number of osteoclast was also higher in SiO₂-treated than PRP-treated group (p= 0.028). In addition, the cells of this group had just started to create Haversian systems in newly formed bone tissues.

Conclusion

Silica demonstrated a superior osteogenic activity over PRP in both short and long term periods. Evidently, they showed no synergistic regenerative effects. Our ad hoc device was efficiently capable of inserting the scaffolds into the injured sites with no diffi-culties or complications.

Silicones in dermatological topical drug formulation: Overview and advances

Silicones, more specifically those of the polydimethylsiloxane type, have been widely used in the pharmaceutical industry for decades, particularly in topical applications. In the dermatological field, in addition to provide undeniable textural and sensory benefits, they can play important functions in the physicochemical properties, stability and biopharmaceutical behavior of these formulations. However, despite the notable advances that can be attributed to the family of silicones, the reputation of these compounds is quite bad. Indeed, silicones, even if they derive from sand, are synthetic compounds. Moreover, they are not biodegradable. They flow into our wastewater and oceans, accumulating in the fauna and flora. This obviously raises many concerns in the common imagination. Do silicones represent a danger for our environment? Should the human species worry about long term toxic effects? Are the claimed benefits really that important? After exploring the various applications of silicone excipients in topical dermatological formulations with a special focus on recent advances which open breathtaking prospects for dermatological applications, this paper shed light on the specific challenges involved in preparation of silicone-based drug as well as, the in vivo behavior of these polymers, the toxicological and environmental risks associated with their application.

A comparison between silicone free and silicone-based emulsions: technological features and in vivo evaluation

Objective

Nowadays, the use of silicones in cosmetic formulation is still controversial, given that “natural” or “biodegradable” components are preferred. Often, the exclusion and/or the discrimination of these excipients from cosmetic field are unmotivated because all things cannot be painted with the same brush. Hence, we want to bring to light and underline the advantages of including silicones in cosmetic emulsions, refuting and debunking some myths related to their use.

Methods

Silicone‐free and silicone‐based emulsions were obtained within an easy homogenization process. Droplet size distribution was assessed by laser diffraction particle size analyser Mastersizer 2000™, and by optical microscopy. The long‐time stability profiles were investigated thanks to the optical analyser Turbiscan® Lab Expert. Diffusing wave spectroscopy (DWS) by Rheolaser Master™ and frequency sweep measurements by Kinexus® Pro Rotational Rheometer were carried out to assess a full rheological characterization. In vivo studies were carried out by the evaluation of Trans Epidermal Water Loss (TEWL) over time on healthy human volunteers. A skin feeling rating was collected from the same volunteers by questionnaire.

Results

From size distribution analysis, a better coherence of data appeared for silicone‐based emulsion, as the size of the droplets was kept unchanged after 1 month, as well as the uniformity parameter. Morphological investigation confirmed a homogenous droplet distribution for both samples. Silicones enhanced the viscosity, compactness and strength of the cream, providing a suitable stability profile both at room temperature and when heated at 40°C. The solid‐like viscoelastic behaviour was assessed in the presence of dynamic oscillatory stresses. The monitoring of TEWL over time demonstrated non‐occlusive properties of emulsions containing silicones, the values of which were comparable to the negative control. Silicone‐based emulsions gained higher scores from the volunteers in silkiness, freshness and softness features, while lower scores were obtained in greasiness compared to silicone‐free emulsions. No cases of irritation were recorded by the candidates.

Conclusion

The presence of specific silicones inside a cosmetic product improved its technological characteristics. The rheological identity and the stability feature showed the real suitability of prepared emulsion as a cosmetic product. Moreover, this study demonstrated that silicone‐based emulsions are safe for the skin and did not cause skin occlusion. Improved skin sensations are registered by potential consumers when silicones are included in the formulation.

Exposure to an accidental trichlorosilane spill: three case reports

Chlorosilane is a hazardous chemical compound which is used as a raw material in the production of silicone. Despite strict restrictions, accidental spillage of chlorosilane is often reported. However, human exposure was rarely reported in the past decades and the effect on humans is barely known. We report cases of human exposure to an accidental trichlorosilane spill. Three middle aged male industrial workers visited our emergency department after exposure to trichlorosilane. They presented with shortness of breath and burns on multiple sites. Chest radiograph and laboratory studies were performed. None of the reports showed serious results and were discharged after conservative management.

The first evidence of the Indian meal moth (Plodia interpunctella) interaction with the silicone moulds

The Indian meal moth (Plodia interpunctella, Lepidoptera) is a common insect species and well-known, widespread kitchen pest. This paper reports the results of their interaction with silicone baking moulds and the evidence for synthetic material decomposition. The obtained fibres exhibited a high level of purification and were characterized by Raman spectroscopy. The reported interaction should be further studied from the biological perspective, as it can be crucial for the remediation of silicones or other synthetic polymers in the environment.

Obstetrics and gynecology residents' satisfaction and self-confidence after anal sphincter injury simulation-based workshop in Indonesia: a pre- and post-intervention comparison study

PURPOSE

Obstetric anal sphincter injury (OASI) is one of the most common complication during delivery. Simulation models using manikin can be used as an effective medical learning method to improve students' abilities before meeting patients. It aimed to describe the development of anal sphincter injury model and assess the resident satisfaction and self-confidence after perineal repair workshop with anal sphincter injury simulator in Indonesia.

METHODS

This was cross-sectional study with evaluation of outcome before and after workshop. We created silicone-latex simulation anal sphincter injury model. Then, we validated this simulation and made it as simulation model for workshop. We asked residents' satisfaction repairing anal sphincter injury using simulation model and residents' self-confidence when practicing the anal sphincter injury repair.

RESULTS

All residents felt the simulation-based workshop was valuable (100%). Most of score for similarity simulation model were good (about 8). The self-assessment of confidence was measured prior to the workshop and after the workshop. The overall self-confidence was increased significantly after workshop in procedure identification external sphincter ani (EAS) (P=0.031), suturing anal mucosa (P=0.001), suturing internal sphincter ani (P=0.001), suturing external sphincter ani (EAS) (P <0.001), evaluation of sphincter ani tone (P=0.016).

CONCLUSION

Anal sphincter injury simulator improves the self-confidence of residents in procedure identification external sphincter ani (EAS), suturing anal mucosa, suturing internal sphincter ani, suturing external sphincter ani (EAS) and evaluation of sphincter ani tone.

A preliminary investigation of underwear as a support for condom evidence in rape and sexual assault cases

Condom lubricants have been found to be a new type of evidence to investigate and analyze in sexual assaults and rape cases. Casework studies highlighted two main types of trace evidence supports collected from the victim and send to forensic laboratories: cotton swabs and victims' underwear. If cotton swabs have been used in most of the recent published research papers, the underwear and the textile effects on the recovery of condom lubricants are under investigated although such studies are very important for the interpretation of the evidence, as highlighted in the Regina v. Andrew Nicholas Malkinson case. This work employed Diffuse Reflection Infrared Fourier Transform Spectroscopy (DRIFTS-FTIR) and Attenuated Total Reflectance (ATR-FTIR) to investigate the content of various feminine underwear and the effect of a laundry procedure on the recovery of any type of evidence. 7 laundry detergents and 9 slips from common brands/models were purchased for this study. No silicones were detected in the laundry detergents, which indicates they are unlikely to generate false positive in terms of detection of silicones. However, silicones were detected in most of the brand new underwear, which was found to be an issue when interpreting the evidence. The laundry procedure was found to significantly affect the evidence, with a strong decrease of the absorbance pre and post washing. Unfortunately, no trend regarding the temperature or the type of textile could be drawn.

Biomechanical and functional comparison of moulded and 3D printed medical silicones

Modern 3D printing of implantable devices provides an important opportunity for the development of personalized implants with good anatomical fit. Nevertheless, 3D printing of silicone has been challenging and the recent advances in technology are provided by the systems which can print medical grade silicone via extrusion. However, the potential impacts of the 3D printing process of silicone on its biomechanical properties has not been studied in sufficient detail. Therefore, the present study compares 3D printed and moulded silicone structures for their cytotoxicity, surface roughness, biomechanical properties, and in vivo tissue reaction. The 3D printing process creates increased nanoscale roughness and noticeably changes microscale topography. Neither the presence of these features nor the differences in processes were found to result in an increase in cytotoxicity or tissue reaction for 3D printed structures, exhibiting limited inflammatory reaction and cell viability above the threshold values. On the contrary, the biomechanical properties have demonstrated significant differences in static and dynamic conditions, and in thermal expansion. Our results demonstrate that 3D printing can be used for establishing a better biomechanical microenvironment for the surrounding tissue of the implant particularly for fragile soft tissue like epithelial mucosa without having any negative effect on the cytotoxicity or in vivo reaction to silicone. For engineering of the implants, however, one must consider the differences in mechanical properties to result in correct and personalized geometry and proper physical interaction with tissues.

Condom evidence: Characterisation, discrimination and classification of pyrolysis-GC-MS profiles

Analysis of condom evidence commonly focusses on the detection of silicone-based lubricants, such as polydimethylsiloxane (PDMS). Although various instruments are used to analyse silicone lubricants, pyrolysis-gas chromatography coupled to mass spectrometry (py-GC-MS) is one of the few instruments that presents immediate applicability to casework. However, considering that this technique detects silicone-based evidence, it is important to evaluate the discrimination potential of the method when applied to various samples. Examination of the variability within a large sample set from an international market is needed to evaluate the most distinguishing compounds likely to be detected in casework. In this study, 70 condoms, personal hygiene products, and lubricants, were analysed using py-GC-MS. Resulting pyrograms were characterised using published spectral databases. Pyrolysates data were extracted and evaluated using multivariate techniques. Qualitative visual inspection of the data, as well as statistical analysis, revealed at least five groups within the dataset. Discrimination was based on four main oligomers, as well as six minor compounds from siloxane degradation. Condom lubricants were found to present a very regular pattern, allowing for the majority of them to be differentiated from personal lubricants.

Amphiphilic silicones to reduce the absorption of small hydrophobic molecules

Silicones (i.e. crosslinked poly(dimethylsiloxane), PDMS) are commonly used material for microfluidic device fabrication. Nonetheless, due to the uncontrollable absorption of small hydrophobic molecules (<1 kDa) into the bulk, its applicability to cell-based drug assays and sensing applications has been limited. Here, we demonstrate the use of substrates made of silicones bulk modified with a poly(ethylene oxide) silane amphiphile (PEO-SA) to reduce hydrophobic small molecule sequestration for cell-based assays. Modified silicone substrates were generated with concentrations of 2 wt.%, 9 wt.% and, 14 wt.% PEO-SA. Incorporation of PEO-SA into the silicone bulk was assessed by FTIR analysis in addition to water contact angle analysis to evaluate surface hydrophobicity. Cell toxicity, absorption of small hydrophobic drugs, and cell response to hydrophobic molecules were also evaluated. Results showed that the incorporation of the PEO-SA into the silicone led to a reduction in water contact angle from 114° to as low as 16° that was stable for at least three months. The modified silicones showed viability values above 85% for NIH-3T3, MCF7, MDA-MB-468, and MDA-MB-231 cell lines. A drug response assay using tamoxifen and the MCF7 cell line showed full recovery of cell toxicity response when exposed to PDMS modified with 9 wt.% or 14 wt.% PEO-SA compared to tissue culture plastic. Therefore, our study supports the use of PEO-SA at concentrations of 9 wt.% or higher for enhanced surface wettability and reduced absorption of small hydrophobic molecules in PDMS-based platforms.

Breast Prosthesis Syndrome: Pathophysiology and Management Algorithm

The cosmetic use of devices like prostheses to increase breast volume is nothing new. It is calculated that millions of people have been exposed to silicone in several ways, including breast implants, and since 1964 there has been uncertainty regarding their safety. We did not find in the literature any studies that reported the appearance of a specific immunological disease in patients with silicone breast implants. Furthermore, there are also neither case-control studies nor reports of patients proving that symptoms of autoimmune/inflammatory syndrome induced by adjuvants (ASIA) occurred after the placement of silicone implants nor that the patients had pre-existing symptoms. Several studies link silicone to allergic reactions and the development of systemic autoimmune diseases; however, other studies deny this association. There are currently several theories about the effect of silicone on the body. One theory with greater acceptance proposes an adjuvant effect of silicone on the development of autoimmune diseases in genetically predisposed patients. However, the variety of symptoms occurring in patients who develop these pathologies leads to doubts about the relationship between the adjuvant effects of a silicone prosthesis may have with a specific autoimmune disease or a mix of these diseases. The lack of consensus on this topic obliges a full review of what has already been reported in the literature to integrate the knowledge and propose a focus for new research on this matter. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Design and Fabrication of a New Expandable Transtibial Liner with Manual Volume Control: A Prototype

Diurnal volume changes is one of the main factors influencing socket fit in transtibial prosthesis and causing pressure problem issues. Embedded bladder liners have been recently a potential approach to deal with this problem. The aim of this technical note was to introduce a new transtibial silicone liner designed based on hybrid socket theory.

To make expandability in the liner, an integrated wax structure was constructed over the selected areas of the positive model and then removed after lamination process. In addition, a mechanical system with manual control was designed to fit the liner with the residual limb volume by pumping the water in or out of the liner through connective tubes.

The results showed that this new design had high reliability in maintaining identical surface pressures after volume changes in laboratory trials. Therefore, it seems that selective expandability of this liner would accommodate residual limb volume fluctuations without disturbing effect on preliminary pressure pattern.

Biofilm formation on three different endotracheal tubes: a prospective clinical trial

BACKGROUND

Biofilm formation on endotracheal tubes (ETTs) is an early and frequent event in mechanically ventilated patients. The biofilm is believed to act as a reservoir for infecting microorganisms and thereby contribute to development and relapses of ventilator-associated pneumonia (VAP). Once a biofilm has formed on an ETT surface, it is difficult to eradicate. This clinical study aimed to compare biofilm formation on three widely used ETTs with different surface properties and to explore factors potentially predictive of biofilm formation.

METHODS

We compared the grade of biofilm formation on ETTs made of uncoated polyvinyl chloride (PVC), silicone-coated PVC, and PVC coated with noble metals after > 24 h of mechanical ventilation in critically ill patients. The comparison was based on scanning electron microscopy of ETT surfaces, biofilm grading, surveillance and biofilm cultures, and occurrence of VAP.

RESULTS

High-grade (score ≥ 7) biofilm formation on the ETTs was associated with development of VAP (OR 4.17 [95% CI 1.14-15.3], p = 0.031). Compared to uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation (OR 0.18 [95% CI 0.06-0.59], p = 0.005, and OR 0.34 [95% CI 0.13-0.93], p = 0.036, respectively). No significant difference was observed between silicon-coated ETTs and noble-metal-coated ETTs (OR 0.54 [95% CI 0.17-1.65], p = 0.278). In 60% of the oropharyngeal cultures and 58% of the endotracheal cultures collected at intubation, the same microorganism was found in the ETT biofilm at extubation. In patients who developed VAP, the causative microbe remained in the biofilm in 56% of cases, despite appropriate antibiotic therapy. High-grade biofilm formation on ETTs was not predicted by either colonization with common VAP pathogens in surveillance cultures or duration of invasive ventilation.

CONCLUSION

High-grade biofilm formation on ETTs was associated with development of VAP. Compared to the uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation. Further research on methods to prevent, monitor, and manage biofilm occurrence is needed.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02284438 . Retrospectively registered on 21 October 2014.

A 29Si, 1H, and 13C Solid-State NMR Study on the Surface Species of Various Depolymerized Organosiloxanes at Silica Surface

Three poly(organosiloxanes) (hydromethyl-, dimethyl-, and epoxymethylsiloxane) of different chain lengths and pendant groups and their mixtures of dimethyl (DMC) or diethyl carbonates (DEC) were applied in the modification of fumed silica nanoparticles (FSNs). The resulting modified silicas were studied in depth using ²⁹Si, ¹H, and ¹³C solid-state NMR spectroscopy, elemental analysis, and nitrogen adsorption-desorption (BET) analysis. The obtained results reveal that the type of grafting, grafting density, and structure of the grafted species at the silica surface depend strongly on the length of organosiloxane polymer and on the nature of the "green" additive, DMC or DEC. The spectral changes observed by solid-state NMR spectroscopy suggest that the major products of the reaction of various organosiloxanes and their DMC or DEC mixtures with the surface are D (RR'Si(O_0.5)₂) and T (RSi(O_0.5)₃) organosiloxane units. It was found that shorter methylhydro (PMHS) and dimethylsiloxane (PDMS) and their mixtures with DMC or DEC form a denser coverage at the silica surface since S_BET diminution is larger and grafting density is higher than the longest epoxymethylsiloxane (CPDMS) used for FSNs modification. Additionally, for FSNs modified with short organosiloxane PMHS/DEC and also medium organosiloxane PDMS/DMC, the dense coverage formation is accompanied by a greater reduction of isolated silanols, as shown by solid-state ²⁹Si NMR spectroscopy, in contrast to reactions with neat organosiloxanes. The surface coverage at FSNs with the longest siloxane (CPDMS) greatly improves with the addition of DMC or DEC. The data on grafting density suggest that molecules in the attached layers of FSNs modified with short PMHS and its mixture of DMC or DEC and medium PDMS and its mixture of DMC form a "vertical" orientation of the grafted methylhydrosiloxane and dimethylsiloxane chains, in contrast to the reaction with PDMS/DEC and epoxide methylsiloxane in the presence of DMC or DEC, which indicates a "horizontal" chain orientation of the grafted methyl and epoxysiloxane molecules. This study highlights the major role of solid-state NMR spectroscopy for comprehensive characterization of solid surfaces.

In vitro evaluation of color and translucency reproduction of maxillofacial prostheses using a computerized system

PURPOSE

Accurate color matching of maxillofacial prostheses to skin is important for esthetics. A computerized color matching system specific to human skin has recently been developed. The purpose of this study was to evaluate the accuracy in color and translucency matching of the computerized color matching system across different skin colors.

MATERIALS AND METHODS

The silicone was colored to simulate 28 different skin colors (n=5) to serve as “target skin colors”. Using a spectrocolorometer (e-skin), color codes were determined for “replicate skin color” fabrication. CIELAB Delta-E between target skin color-replicate skin color pairs and translucency parameter were calculated. CIELAB Delta-E values were compared with one-way ANOVA and Tukey multiple-comparison. The agreement between L*, a*, b* and translucency parameter of target skin colors and replicate skin color were calculated by a two-way mixed average measures intraclass correlation coefficient. Translucency parameter of target skin color-replicate skin color pairs were compared with Paired t-test (α=.05).

RESULTS

The mean CIELAB Delta-E value was 3.83 and significant differences were found among colors. The intraclass correlation coefficient showed excellent reliability for L*, a*, b* and good reliability for translucency parameter (P<.001). The mean translucency parameter of replicate skin colors was significantly higher than that of translucency parameter.

CONCLUSION

The computerized color matching system specific to human skin was found to be reliable in terms of color and translucency between target skin colors and replicate skin color.

Dynamic rheological comparison of silicones for podiatry applications

PURPOSE

This work shows an effective methodology to evaluate the dynamic viscoelastic behavior of silicones for application in podiatry. The aim is to characterize, compare their viscoelastic properties according to the dynamic stresses they can be presumably subjected when used in podiatry orthotic applications. These results provide a deeper insight which extends the previous creep-recovery results to the world of dynamic stresses developed in physical activity. In this context, it shoulod be taken into account that an orthoses can subjected to a set of static and dynamic shear and compressive forces.

METHODS

Two different podiatric silicones, Blanda-blanda and Master, from Herbitas, are characterized by dynamic rheological methods. Three kinds of rheological tests are considered: shear stress sweep, compression frequency sweep and shear frequency sweep, all the three with simultaneous control of the static force at three different levels. The static force represents a static load like that produced by the weight of a human body on a shoe insole. In a practical sense, dynamic stresses are related to physical activity and are needed to evaluate the frequency effect on the viscoelastic behavior of the material. It is considered that the dynamic stresses can be applied in compression and shear since, in practice, the way the stresses are applied in real life depends on the orthoses geometry and its exact location with respect to the foot and shoe. The effects of static and dynamic loads are individualized and compared to each other through the relations between the elastic constants for isotropic materials.

CONCLUSIONS

The overall proposed experimental methodology can provide very insightful information for better selection of materials in podiatry applications. This study focuses on the rheological characterization to choose the right silicone for each podiatric application, taking into account the dynamic viscoelastic requirements associated to the physical activity of user. Accordingly, one soft and one hard silicones of common use in podiatry were tested. Each of the two silicones exhibit not only different moduli values, but also, a different kind of dependence of the dynamic moduli with respect to the static load. In the case of the soft sample a linear trend is observed but in the case of of the hard one the dependence is of the power law type. Moreover, these samples exhibit very different Poisson's coefficient values for compression stresses lower than 20 kPa, and almost the same values for stresses above 40 kPa. That different dependence of the Poisson's ratio on the static load should also be taken into account for material selection in customized podiatry applications, where static and dynamic loads are strongly dependent on the individual weight and activity.

A Systematic Review of Benefit of Silicone Intubation in Endoscopic Dacryocystorhinostomy

Objectives

Insertion of a silicone stent during endoscopic dacryocystorhinostomy (DCR) is the most common procedure to prevent rhinostomy closure. It has been claimed that silicone intubation improves the surgical outcomes of endoscopic DCR. However, many reports have documented an equally high success rate for surgery without silicone intubation. Accordingly, we conducted a systematic review and meta-analysis to clarify the outcomes of endoscopic DCR with and without silicone intubation and determine whether silicone intubation is actually beneficial for patients.

Methods

PubMed, Embase, and Cochrane Library databases were searched to identify relevant controlled trials evaluating endoscopic DCR with and without silicone intubation. The search was restricted to English articles published between January 2007 and December 2016. Relevant articles were reviewed to obtain information pertaining to interventions and outcomes. We also performed a meta-analysis of the relevant literature.

Results

In total, 1,216 patients included in 12 randomized controlled trials were pooled. A total of 1,239 endoscopic DCR procedures were performed, and silicone stents were used in 533 procedures. The overall success rate for endoscopic DCR was 91.9% (1,139/1,239), while the success rates with and without silicone intubation were 92.9% (495/533) and 91.2% (644/706), respectively. There was no statistically significant heterogeneity among the included studies. A meta-analysis using a fixed-effects models showed no significant difference in the success rate between endoscopic DCR with silicone intubation and that without silicone intubation (OR, 1.38; 95% CI, 0.89 to 2.12; P=0.148; z=1.45). Furthermore, there were no significant differences with regard to surgical complications such as synechia, granulation, and postoperative bleeding.

Conclusion

The findings of our meta-analysis suggest that the success rate and postoperative complication rate for endoscopic DCR is not influenced by the use of silicone intubation during the procedure.

The Clinical Efficacy of Silicone Stents for Endoscopic Dacryocystorhinostomy: A Meta-Analysis

We evaluated the effect of silicone stent use during endoscopic dacryocystorhinostomy on postoperative morbidities in comparison with versus without a silicone stent. Two authors independently searched six databases (PubMed, Embase, Scopus, the Web of Science, the Cochrane library, and Google Scholar) from inception of article collection to July 2017. The analysis included prospective randomized studies that compared intraoperative silicone stent insertion (silicone group) with no application of a silicone stent (control group), in which the outcomes of interest were success rate (lacrimal passage patent check with syringing, symptom relief, or endoscopic confirmation of fluorescein dye from the opening of Hasner's valve) and morbidities (e.g., postoperative bleeding, rhinostomy closure, granulation tissue, synechia, and eyelid problems) after certain follow-up periods (over 10 weeks). Nine studies involving a total of 587 participants were included. Functional success rates tended to be higher in the silicone group than in the control, but there was no statistically significant difference in success rates (odds ratio, 1.45; 95% confidence interval, 0.77 to 2.73). According to the surgical type such as mucosal removal and mucosal flap surgery, the results from types didn't demonstrate any significant effect, but the mucosal flap technique seemed to be more beneficial. Regarding postoperative morbidities, although the outcomes of the groups did not present any statistically significant difference, eyelid problems and postoperative bleeding tended to occur more frequently in the silicone group, but rhinostomy closure tended to occur more frequently in the control group. Success and morbidity rates showed no difference between the silicone stent group and control group in the meta-analysis. However, additional analyses revealed that the success rate of endonasal dacryocystorhinostomy using silicone intubation with mucosal flap has shown an improving trend, and morbidities such as granulation and synechia showed decreasing trends compared with the group without silicone intubation.

Two hundreds cases of ASIA syndrome following silicone implants: a comparative study of 30 years and a review of current literature

In this study, we compared one hundred patients with autoimmune/inflammatory syndrome induced by adjuvants (ASIA) due to silicone implant incompatibility syndrome diagnosed in 2014 in Maastricht, the Netherlands, with one hundred historical patients with adjuvant breast disease diagnosed in the Baylor College of Medicine, Houston, USA, between 1985 and 1992. Similarities and differences between these two cohorts were identified to determine whether the spectrum of silicone-related disease changed during the last 30 years. Patients with complaints possibly due to silicone-filled breast implants were prospectively examined in the Reinaert Clinic, Maastricht, the Netherlands between January 2014 and October 2014. All patients were evaluated for the fulfilment of ASIA criteria. Results were compared to results of the Baylor College cohort and 18 other reviewed historical cohorts. Clinical manifestations between the Maastricht and Baylor College cohorts were comparable. Fatigue was observed in 98 current patients and in 95 historical patients. Arthralgia was observed in 91 versus 81 historical patients. Myalgia was observed in 54 versus 91 patients. Cognitive impairment was observed in 78 versus 81 patients, pyrexia was observed in 64 versus 52 patients, sicca complaints in 73 versus 72 patients and severe neurological manifestations in 20 versus 32 patients. From the 54 patients who underwent removal of their silicone breast implant, 50 % (n = 27) of the patients experienced improvement of complaints after explantation of the implant. Also, in the 18 reviewed historical cohorts, similar clinical manifestations were described. Our findings suggest that no major changes were present in the observed clinical manifestations between the Maastricht and Baylor College cohorts. Also, despite changes in the principal constituents of the silicone implants during the past fifty years, silicone remained an adjuvant that may ‘bleed’ and subsequently may be a chronic stimulus to the immune system resulting in similar clinical manifestations as observed in the Maastricht cohort, the Baylor College cohort and 18 other large cohorts of patients. We therefore conclude that silicone-related disease has not changed during the last 30 years.

Are organosilicon surfactants safe for bees or humans?

Organosilicon surfactants are the most potent adjuvants available for formulating and applying agricultural pesticides and fertilizers, household cleaning and personal care products, dental impressions and medicines. Risk assessment of pesticides, drugs or personal care products that takes into account only active ingredients without the other formulation ingredients and adjuvants commonly used in their application will miss important toxicity outcomes detrimental to non-target species including pollinators and humans. Over a billion pounds of organosilicon surfactants from all uses are produced globally per year, making this a major component of the chemical landscape to which bees and humans are exposed. These silicones, like most "inerts", are generally recognized as safe, have no mandated tolerances, and their residues are largely unmonitored. Lack of their public disclosure and adequate analytical methods constrains evaluation of their risk. Organosilicon surfactants, the most super-spreading and -penetrating adjuvants available, at relevant exposure levels impair honey bee learning, are acutely toxic, and in combination with bee viruses cause synergistic mortality. Organosilicon surfactants need to be regulated as a separate class of "inerts" from the more common silicones. In turn, impacts of organosilicon surfactant exposures on humans need to be evaluated. Silicones in their great diversity probably represent the single most ubiquitous environmental class of global synthetic pollutants. Do honey bees, a model environmental indicator organism, forewarn of hidden risks to humans of ubiquitous silicone exposures?

Evolution of consciousness of exposure to siloxanes-review of publications

The purpose of this description is to review scientific literature from 1944 to 2017 as a source of information on the reasons for the increased interest in siloxanes (silicones). Not only the research area, but first, the changes in the tendency of research aims are important issues in the evaluation. On the one hand, the authors emphasize the unique properties of linear and cyclic siloxanes, providing many examples of beneficial applications, and on the other hand, there are some warnings of overcoming of the safety barrier of their presence in human environment. Analyzing the results from the SCOPUS database, it can be argued that the increased interest of scientists and government agencies particularly relates to the analysis of siloxanes in biological and environmental samples. This is caused not only by the widespread use of various siloxanes in the pharmaceutical, medical, cosmetic and food industries, but also by the direct contact of these compounds with tissues, as well as an increased access to knowledge and modern research tools that have developed the awareness of hazards. The development of research methods enables not only constant monitoring of progressively lower siloxanes concentrations in various samples, but because of the specificity of these methods, it also enables an identification of specific siloxane compounds and evaluation of their effects on humans and environment. This paper discusses the issues of the evolution of consciousness of exposure to siloxanes due to their increased synthesis and widespread use in many areas of human life, which contributes to environmental pollution.

Extensive silicone lymphadenopathy after breast implant insertion mimicking malignant lymphadenopathy

Silicone implants are widely used in aesthetic and reconstructive breast surgery. Silicone lymphadenopathy is a well-known rare complication of implant insertion. Silicone leakage from a rupture or silicone bleeding can accumulate in lymph nodes. Foreign body reactions in the affected lymph nodes may be misdiagnosed as metastasis or malignant lymphadeno pathy upon initial presentation if silicone lymphadenopathy is not considered in the initial diagnosis. We report a case of siliconoma with extensive involvement of multiple lymph nodes mimicking malignant features to emphasize that clinicians should carefully evaluate each patient's medical history and disease status during differential diagnosis.

Assessing cosmetic results after conventional thyroidectomy using the EASY-EYE_C: a double-blind randomized controlled trial

Purpose

The incidence of thyroid cancer is relatively high, especially in young women, and postoperative scarring after thyroidectomy is an important problem for both patients and clinicians. Currently, there is no available product that can be used for wound protection during thyroid surgery. We used the EASY-EYE_C, a new silicone-based wound protector.

Methods

We conducted a double-blind randomized controlled trial to assess the efficacy of the EASY-EYE_C with surgical scars. We studied 66 patients who underwent conventional total thyroidectomy or hemithyroidectomy performed by a single surgeon from August 2015 to June 2016. At 6-week follow-up, a single blinded physician observed the wounds to make clinical assessments using the Patient and Observer Scar Assessment Scale (POSAS), the Vancouver Scar Scale (VSS), and a modified Stony Brook Scar Evaluation Scale (SBSES).

Results

There were no significant differences by sex, age, type of surgery, body mass index, length of wound, incision site (from sternal notch), or thyroid weight, but the duration of operation was significantly shorter in the experimental group (E group). The e-group also had better POSAS scores than the control group (C group), with means of 43.2 (standard deviation [SD], ±15.9) versus 68.3 (SD, ±21.5), respectively (P < 0.05). The modified SBSES and VSS scores were similar to those from the POSAS.

Conclusion

In this study, all scores for evaluating outcomes were higher in the E group than in the C group. In addition, the operation time was significantly shorter in the E group. Therefore, the EASY-EYE_C may be useful for improving the cosmetic outcomes of conventional thyroid surgery.

A new treatment for reliable functional and esthetic outcome after local facial flap reconstruction: a transparent polycarbonate facial mask with silicone sheeting

BACKGROUND

Facial flap surgery predominantly leads to good functional results. However, in some cases, it can cause unsatisfactory esthetic results. They include persistent erythema, pincushioning, and development of hypertrophic scars. Conservative, reliable treatment for facial flaps is lacking. Pressure and silicone therapy have proven to result in significant improvement in scar erythema, pliability, and thickness in postburn hypertrophic scars. By combining these therapies in a facial mask, the esthetic outcome of facial flaps could be improved. In this retrospective study, the efficacy of a unique transparent face mask containing silicone sheets on the esthetic outcome of postsurgical facial flaps is assessed.

METHODS

Twenty-one patients were assigned to facial pressure mask therapy after they underwent facial flap surgery between July 2012 and September 2015. Patients were treated for a mean duration of 46 weeks. The effects of pressure mask therapy were examined by means of the Patient and Observer Scar Assessment Scale (POSAS).

RESULTS

All POSAS components showed a reduction between start and end of therapy, while itchiness, pigmentation, pliability, thickness, and relief of the flap improved significantly (P < 0.05). Mean total and patient score showed significant reduction between start and end of therapy.

CONCLUSIONS

This study shows that a facial pressure mask layered with silicone results in noticeable flap improvement with a long-lasting result. Level of Evidence: Level III, therapeutic study.

Silicone Implant Sandwiched between Intact Nasal Bones with Fractured Nasal Bone Segments

As the number of people who have undergone augmentation rhinoplasty has increased recently, nasal fractures are becoming more common after rhinoplasty. A silicone implant can affect the nasal fracture pattern, but there is no significant difference in treatment methods commonly. A 28-year-old female who had undergone augmentation visited our clinic with a nasal fracture. Computed tomography revealed that the silicone implant was sandwiched between the intact nasal bones with fractured bone fragments. In this case, open reduction was inevitable and a new silicone implant was inserted after reduction. Migration of the silicone implant beneath the nasal bone is a very rare phenomenon, but its accurate prevention and diagnosis is important because a closed reduction is impossible.

Rheumatic hand's clinical, functional and imagiological correlations following metacarpophalangeal joint silicone arthroplasty

Objective

Evaluation of rheumatoid hand-associated metacarpophalangeal joint silicone arthroplasty most often relies on functional scores alone. This study aimed to understand the correlation between perceived and observed function, strength, and alignment.

Methods

Cross-sectional study including all 11 women (15 hands) submitted to second to fifth metacarpophalangeal joint arthroplasty due to rheumatoid arthritis involvement for a time period of seven years. Measurements relied on the Michigan Hand Outcomes Questionnaire, Lafayette Purdue Pegboard, pinch and grip strength, and analysis of a lateral “OK-sign” X-ray view. Correlation analysis used Spearman's coefficient, assuming statistical significance for p-values < 0.05.

Results

Objective function was strongly correlated with all other variables (p < 0.05), while perceived function failed to correlate with articular alignment in both measurements (p = 0.240 and p = 0.354). Strength and alignment were also strongly correlated (p < 0.05).

Conclusions

Most measurements strongly correlate with each other, with emphasis on objective dexterity measurement.

Biological relevance of effects following chronic administration of octamethylcyclotetrasiloxane (D4) in Fischer 344 rats

Octamethylcyclotetrasiloxane (D4) is a cyclic siloxane primarily used as a monomer or intermediate in the production of silicone polymers resulting in potential exposure of workers, and potential low level inhalation or dermal exposure for consumers and the general public. Following a two-year inhalation toxicity study with D4 in rats, increases in uterine endometrial cystic hyperplasia and adenomas were observed at the highest concentration of D4 administered (700ppm). No other neoplasms were increased with D4 treatment. In addition, chronic inhalation exposure of rats to D4 induced changes in relative liver and kidney weights, and produced a chronic nephropathy. This manuscript examines the biological relevance and possible modes of action for the effects observed in the F344 rat following chronic inhalation exposure to D4. D4 is not genotoxic and appears to exert its effects through a nongenotoxic mode of action. An alteration in the estrous cycle in the aging F344 rat was the most likely mode of action for the observed uterine effects following chronic inhalation exposure. Data support the conclusion that D4 acts indirectly via a dopamine-like mechanism leading to alteration of the pituitary control of the estrous cycle in aging F344 rats with a decrease in progesterone and an increase in the estrogen/progesterone ratio most likely induced by a decrease in prolactin concentration. D4 also inhibited the pre-ovulatory LH surge causing a delay in ovulation, persistent follicles and thus a prolonged exposure to elevated estrogen in the adult Sprague Dawely rat. A lengthening of the estrous cycle in the F344 rat with an increase in endogenous estrogen was also induced by D4 inhalation. Although the mode of action responsible for induction of uterine adenomas in the female F344 rat has not been clearly confirmed, the subtlety of effects on the effects of D4 on cyclicity may prevent further assessment and definition of the mode of action. The occurrence of uterine endometrial adenoma in the rat is not relevant for human risk characterization because (1) there are differences in ovulatory cycle regulation in rats compared to humans, (2) cystic hyperplasia without atypia in women is not a cancer precursor, and (3) there is no endometrial lesion in women that is directly analogous to endometrial adenoma in the rat. The effects of D4 on liver are due to a phenobarbital-like mechanism that results in induction of cytochrome P450 and other enzymes of xenobiotic biotransformation. The liver effects are adaptive and not adverse. Kidney findings included chonic progressive nephropathy, a rat lesion that has no counterpart in the human and that should not be used in human risk assessment.

Self injection of foreign materials into the penis

Injection of the subcutaneous tissues of the penis for enlargement of penile girth has been practised for many years by laypeople and medical practitioners alike. However, with recognition of the complications, the practice has died out. We report a series of five patients who presented having injected foreign materials into the subcutaneous tissues of their penises, including paraffin and mineral oils. Our patients had a variable time course of presentation ranging from 1 day following injection to over 26 years. Self-injection of the subcutaneous tissues of the penis is an unusual presentation for a penile mass but should be considered as a differential diagnosis in patients with a long latent period to presentation or with characteristic magnetic resonance imaging and histological appearances.

Properties, performance and associated hazards of state-of-the-art durable water repellent (DWR) chemistry for textile finishing

Following the phase-out of long-chain per- and polyfluoroalkyl substances (PFASs), the textile industry had to find alternatives for side-chain fluorinated polymer based durable water repellent (DWR) chemistries that incorporated long perfluoroalkyl side chains. This phase-out and subsequent substitution with alternatives has resulted in a market where both fluorinated and non-fluorinated DWRs are available. These DWR alternatives can be divided into four broad groups that reflect their basic chemistry: side-chain fluorinated polymers, silicones, hydrocarbons and other chemistries (includes dendrimer and inorganic nanoparticle chemistries). In this critical review, the alternative DWRs are assessed with regards to their structural properties and connected performance, loss and degradation processes resulting in diffuse environmental emissions, and hazard profiles for selected emitted substances. Our review shows that there are large differences in performance between the alternative DWRs, most importantly the lack of oil repellence of non-fluorinated alternatives. It also shows that for all alternatives, impurities and/or degradation products of the DWR chemistries are diffusively emitted to the environment. Our hazard ranking suggests that hydrocarbon based DWR is the most environmentally benign, followed by silicone and side-chain fluorinated polymer-based DWR chemistries. Industrial commitments to reduce the levels of impurities in silicone based and side-chain fluorinated polymer based DWR formulations will lower the actual risks. There is a lack of information on the hazards associated with DWRs, in particular for the dendrimer and inorganic nanoparticle chemistries, and these data gaps must be filled. Until environmentally safe alternatives, which provide the required performance, are available our recommendation is to choose DWR chemistry on a case-by-case basis, always weighing the benefits connected to increased performance against the risks to the environment and human health.

Silicone Implant-Based Paranasal Augmentation for Mild Midface Concavity

Background

Midface concavity is a relatively common facial feature in East Asian populations. Paranasal augmentation is becoming an increasingly popular procedure for patients with mild concavity and normal occlusion. In this study, we evaluate clinical outcomes following a series of paranasal augmentation.

Methods

A retrospective review was performed for patients with Class I occlusion who had undergone bilateral paranasal augmentation using custom-made silicone implants, between October 2005 and September 2013. Patient charts were reviewed for demographic information, concomitant operations, and postoperative complications. Preoperative and postoperative (1-month) photographs were used to evaluate operative outcome.

Results

The review identified a total of 93 patients meeting study criteria. Overall, aesthetic outcomes were satisfactory. Five-millimeter thick silicone implant was used in 81 cases, and the mean augmentation was 4.26 mm for this thickness. Among the 93 patients, 2 patients required immediate implant removal due to discomfort. An additional 3 patients experienced implant migration without any extrusion. Nine patients complained of transient paresthesia, which had resolved by 2 weeks. There were no cases of hematoma or infection. All patients reported improvement in their lateral profile and were pleased at follow-up. Complications that arose postoperatively included 9 cases of numbness in the upper lip and 3 cases of implant migration. All cases yielded satisfactory results without persisting complications. Sensations were fully restored postoperatively after 1 to 2 weeks.

Conclusion

Paranasal augmentation with custom-made silicone implants is a simple, safe, and inexpensive method that can readily improve the lateral profile of a patient with normal occlusion. When combined with other aesthetic procedures, paranasal augmentation can synergistically improve outcome and lead to greater patient satisfaction.

Silicone-containing aqueous polymer dispersions with hybrid particle structure

In this paper the synthesis, characterization and application of silicone-containing aqueous polymer dispersions (APD) with hybrid particle structure are reviewed based on available literature data. Advantages of synthesis of dispersions with hybrid particle structure over blending of individual dispersions are pointed out. Three main processes leading to silicone-containing hybrid APD are identified and described in detail: (1) emulsion polymerization of organic unsaturated monomers in aqueous dispersions of silicone polymers or copolymers, (2) emulsion copolymerization of unsaturated organic monomers with alkoxysilanes or polysiloxanes with unsaturated functionality and (3) emulsion polymerization of alkoxysilanes (in particular with unsaturated functionality) and/or cyclic siloxanes in organic polymer dispersions. The effect of various factors on the properties of such hybrid APD and films as well as on hybrid particles composition and morphology is presented. It is shown that core-shell morphology where silicones constitute either the core or the shell is predominant in hybrid particles. Main applications of silicone-containing hybrid APD and related hybrid particles are reviewed including (1) coatings which show specific surface properties such as enhanced water repellency or antisoiling or antigraffiti properties due to migration of silicone to the surface, and (2) impact modifiers for thermoplastics and thermosets. Other processes in which silicone-containing particles with hybrid structure can be obtained (miniemulsion polymerization, polymerization in non-aqueous media, hybridization of organic polymer and polysiloxane, emulsion polymerization of silicone monomers in silicone polymer dispersions and physical methods) are also discussed. Prospects for further developments in the area of silicone-containing hybrid APD and related hybrid particles are presented.

A multicentre clinical evaluation of Cuticell Contact silicone wound contact layer in daily practice

OBJECTIVE

To evaluate clinically the performance of Cuticell Contact, a silicone-based primary contact wound dressing.

BACKGROUND

Primary contact dressings that allow removal of exudate while protecting the wound bed during dressing changes are a key tool in wound management. Silicone dressings are of particular interest owing to their excellent conformability, pain-free dressing changes, and low toxicity. Cuticell Contact is a silicone-based wound dressing thought to provide these desirable benefits.

METHOD

In this evaluation, 38 patients with 40 wounds of a variety of aetiologies and anatomical locations managed with Cuticell Contact and secondary dressings were observed in 8 centres across Germany and the Netherlands. The observation period ranged from 2-42 days (mean 21 days, median 18 days). At the end of the observation, Cuticell Contact was evaluated for permeability to exudate, nonadherence to the wound bed, pain at dressing change, and overall performance. The condition of the wound bed, wound surface area, and levels of exudate were recorded at baseline, at each dressing change, and at the end of the evaluation, along with the condition of the wound edge and peri-wound skin.

RESULTS

Wounds managed with Cuticell Contact showed improvement in the wound bed as evidenced by an increase in wounds with complete granulation from 12.5% (n=40) to 26.5% (n=34), and wounds with partial or complete epithelialisation from 35% to 82.4%. Cuticell Contact was assessed at the end of the evaluation as nonadherent to the wound in 91.2% of cases (n=34), and 93.3% of dressing changes (n=104) were deemed pain free. Wound surface area decreased by a mean of 19.9%. Cuticell Contact was rated satisfactory for permeability to wound exudate in 82.4% of responses and overall satisfaction with the dressing performance was also 82.4%.

CONCLUSION

Cuticell Contact is a soft silicone dressing that is easy to use, efficacious in supporting wound healing through protecting the wound bed, and facilitates atraumatic dressing changes.

Using silicone technology to maintain healthy skin in stoma care

The use of silicone in stoma care has grown in recent years and may be considered the next step in the revolutionary development of stoma-care products. Clinical nurse specialists aim to provide evidence-based care at all times, and the same is true for stoma-care nurses. Preventing harm by choosing products that have a sound research base provides the patients with up-to-date, quality care, which enables them to adapt to life with a stoma and return to 'normal' functioning. This article explores the issue of peristomal skin problems and the development of silicone products, and highlights scenarios where it could be an advantage to choose a silicone product.

Maxillofacial prosthetic materials- an inclination towards silicones

There have been constant searches and researches which are taking place in the field of dental materials to best suit the ideal selection criteria to satisfy the functionality, biocompatibility, aesthetics as well as the durability as a maxillofacial material. Among all the different materials, Silicone is the most popularly used, but still studies are carried out to overcome their weaknesses and to come out with a material which can be labeled as the "ideal maxillofacial prosthetic material". This article comprises the materials which were and are in use and the reason for their unpopularity. It also gives us a scope to understand the major fields where the materials lack and thus needs improvement to render an individual with the best maxillo-facial prosthesis.

A simplified approach for the rehabilitation of an auricular defect: a case report

BACKGROUND AND AIM

Replacement of missing ear is a challenging task in which extensive array of materials and techniques have been employed. Materials such as silicones and methacrylate acrylic resins have been widely used for auricular prosthesis. This article describes a simplified procedure for fabricating resilient heat-cured acrylic resin auricular prosthesis, retained with a custom-made acrylic bar with ball attachments.

CASE DESCRIPTION AND METHODS

A male patient was reported with right ear loss. A modified technique was preferred to fabricate ear prosthesis with resilient heat-cured acrylic resin in which heat-cured acrylic retentive bar was incorporated.

FINDINGS AND OUTCOMES

Contrary to silicones, resilient heat-cured acrylic resin was more economical and compatible with acrylic retentive bar and resulted in a more long-lasting auricular prosthesis.

CONCLUSION

Resilient heat-cured acrylic resin was proven to be a better alternative in terms of strength and durability.

CLINICAL RELEVANCE

This article presents an economical and simplified approach for the fabrication of prosthesis for a missing ear.

Canalization and maintaining the patency of external auditory canal in a congenital aural atresia patient: a multidisciplinary approach

This clinical report describes the role of a prosthodontist in rehabilitating a patient with congenital aural atresia. The external auditory canal and structure in the middle ear fail to develop completely in cases of congenital aural atresia. Canalization procedure to establish the communication between the external ear and middle ear, and maintaining the patency of the created canal plays an important role in the success of treatment in selected patients. Post Operative external auditory canal restenosis is the most common complication after congenital aural atresia surgery. The prosthodontist has an important role in assisting ENT surgeons in canalization procedure and also maintaining the patency of the canal during healing phase.

[Risk factors for recurrent retinal detachment]

OBJECTIVE

To determine the risk factors associated with recurrent retinal detachment in patients vitrectomized.

METHODS

Case-control study nested in a cohort. We included patients with a diagnosis of rhegmatogenous retinal detachment treated with vitrectomy for one year, with a six months follow-up. We monitored the presence of incident event in the emergency department, and the examination room. Statistical analysis was performed by descriptive statistics (median, minimum and maximum) and inferential statistics (chi-squared test, Cox regression, Kaplan-Meier).

RESULTS

A population of 94 patients with a median age of 55 years (21-83) was analyzed. The silicone was the most widely used type of tamponade in 62 patients (66 %) and recurrent retinal detachment occurred in 19 cases (20 %). In the relation between the non-relapse group and the relapse group, the statistically significant variable was the use of silicone (p = 0.05, OR = 0.03, 0.013-0.98), wich had a lower probability of recurrent detachment compared with the use of sulfur hexafluoride (SF6 gas) (p = 0.012).

CONCLUSIONS

The use of silicone compared with the use of SF6 gas has shown to be a protective factor for recurrent retinal detachment; however, the choice of method of tamponade should be individualized for each patient.

A tie-over dressing using a silicone tube to graft deep wounds

Background

The most common cause of skin graft failure is the collection of blood or serous fluid underneath the graft. In our study, we describe the use of silicone tube for tie-over dressing to secure the skin graft margins with the aim of decreasing loss of the skin graft, particularly in grafting of deep wounds.

Methods

Between March 2008 and July 2011, we used this technique in 17 patients with skin defects with depths ranging from 3.5 to 8 mm (mean, 5.5 mm). First, the skin graft was sutured with 3/0 silk suture material from its corners. Then, a silicone round drain tube was sutured with 3/0 absorbable polyglactin 910 over the margins of the graft. Finally, long silk threads were tied over the bolus dressing, and the tie-over dressing was completed in the usual fashion.

Results

The mean follow-up was 7 months (range, 2-10 months) in the outpatient clinic. Graft loss on the graft margins due to hematoma or seroma was not developed. The results of adhesion between the graft and wound bed peripherally was excellent.

Conclusions

In our study, we suggest that use of a silicone tube for additional pressure on the edges of skin grafts in case of reconstruction of deep skin defects.

Augmentation mammaplasty using implants: a review

One of the techniques for augmentation mammaplasty is the procedure using implants. Even though this technique has been used for many years, there are still several controversial issues to be discussed and overcome for patient safety. In this review article, capsular contracture, leak or rupture of the implants, possible systemic disease, relation with breast cancer, and recent problems with Poly Implant Prothese implants are described and discussed.

Mastoid obliteration with silicone blocks after canal wall down mastoidectomy

Objectives

To evaluate the usefulness of silicone blocks as graft material for mastoid cavity obliteration in the prevention of problematic mastoid cavities after canal wall down mastoidectomies.

Methods

Retrospective evaluation of 20 patients who underwent mastoid obliteration with silicone blocks between 2002 and 2009 at the Chonnam National University Hospital. The cases consisted of 17 patients with chronic otitis media with cholesteatoma and 3 patients with adhesive otitis media. The postoperative follow-up period was an average 49 months (range, 6 to 90 months). The surgical technique used at our institution composed four major steps: First, the canal wall down mastoidectomy was performed and the middle ear procedure was completed. The silicone blocks were used to fill up the mastoidectomized cavity. Then, a cortical bone pate was used to cover the surface of the silicone blocks. Finally, temporalis fascia and a split musculoperiosteal flap were used to surround the bone pate for reinforcement of the reconstructed canal wall. We examined postoperative success rate and hearing outcomes.

Results

In 19 cases (95%), the reconstructed canal wall maintained a cylindrical shape and the ear drum healed without perforation. In only 1 case (5%), the reconstructed canal wall was destroyed with ear drum perforation. The mean improvement in air-bone gap was about 12 dB (P<0.05), and the mean improvement in air-conduction was about 16 dB (P<0.05).

Conclusion

We suggest that silicone blocks could be valuable resources as graft materials for mastoid obliteration after canal wall down mastoidectomies.

Foreign body inclusion cyst of the nasal radix after augmentation rhinoplasty

Development of a cystic mass on the nasal dorsum is a very rare complication of aesthetic rhinoplasty. Most reported cases are of mucous cyst and entrapment of the nasal mucosa in the subcutaneous space due to traumatic surgical technique has been suggested as a presumptive pathogenesis. Here, we report a case of dorsal nasal cyst that had a different pathogenesis for cyst formation. A 58-yr-old woman developed a large cystic mass on the nasal radix 30 yr after augmentation rhinoplasty with silicone material. The mass was removed via a direct open approach and the pathology findings revealed a foreign body inclusion cyst associated with silicone. Successful nasal reconstruction was performed with autologous cartilages. Discussion and a brief review of the literature will be focused on the pathophysiology of and treatment options for a postrhinoplasty dorsal cyst.