Classification of Foreign Body Reactions due to Industrial Silicone Injection.

BACKGROUND: A foreign body reaction (FBR) is a typical tissue response to a biomaterial that has been injected or implanted in human body tissue. There has been a lack of data on the classification of foreign body reaction to silicone injection, which can describe the pattern of body tissue responses to silicone. OBJECTIVE: Determine the foreign body reaction to silicone injection. METHOD: We modified the classification proposed by Duranti and colleagues, which has categorized a FBR to hyaluronic acid injection into a new classification of an FBR to silicone injection. A cohort study of 31 women suffering from silicone-induced granulomas on their chin was conducted. Granulomatous tissue and submental skin were stained with hematoxylin-eosin and evaluated. RESULTS: Our data revealed that there were at least 7 categories of FBRs to silicone injection that could be developed. Categories 1 to 4 showed inflammatory activity, and categories 5 to 8 showed tissue repair by fibrosis. CONCLUSION: Using histopathological staining, we are able to sequence the steps of body reactions to silicone injection. Initial inflammatory reaction is then replaced by fibrosis process repairing the damaged tissues. The process depends on the host immune tolerance.

Soft tissue reactions in patients with bone anchored hearing aids.

AIMS: To establish the incidence and correlation between the degree of soft tissue reaction and the body mass index (BMI) according to age and gender after a bone anchored hearing aid (BAHA) implant. METHODS: We did a 1-9-year follow-up for the all the patients who underwent surgery in our department with BAHA implant system. Soft tissue reactions were classified in accordance with the Holgers classification on regular patient visits. BMI was calculated for each patient, and changes were recorded at least once a year. RESULTS: 47 patients were evaluated. 58% were operated on for chronic otitis with mixed or conductive hearing loss; 20% had unilateral or bilateral atresia and 16% had single sided deafness (SSD); other indications were otosclerosis and syndromic patients. The grade of Holgers classification significantly correlated at a 0.001 level with BMI (Spearmans rho 0.452). Holgers grade also differed significantly between the sexes-skin reactions in females were less frequent. An ANOVA test did not reveal any statistical difference between patients with dissimilar indications for BAHA. CONCLUSION: If performed carefully, BAHA surgery produces a favorable outcome. The Holgers grade may change as time passes. If skin reactions appear, they can be treated through local or systemic therapy, and they may turn into a normal grade. Adipose patients should be treated with special care because they are more prone to soft tissue reactions.

[Histological and immunohistochemical study of capsular contracture in an animal model--a comparison of two implants according to a modification of Wilflingseder's classification]. / Histologische und immunhistochemische Untersuchung zur Kapselfibrose im Tiermodell--Vergleich zweier Implantate mittels einer histologischen Klassifikation in Modifikation nach Wilflingseder.

BACKGROUND: The influence of silicone implants on the formation of a periprosthetic capsule can be well examined in animal studies. New implant materials have been developed to reduce capsular contracture. In order to evaluate the capsule formation, Wilflingseder et al. developed a histological score system. Because of new knowledge in the development of capsular contracture, the Wilflingseder classification is no longer appropriate. Current references are not considered so that a modification is required. MATERIAL AND METHOD: In a randomised, experimental animal study 31 mini-implants were implanted into the dorsum of female Wistar rats [17 smooth, 10 mL saline-filled silicone implants (Group A) and 14 titanium coated silicone implants (Group B)]. After 12 (group A/B12) or 36 (group A/B36) weeks, surgical removal of the implants with subsequent histomorphological and immunohistochemical examination of periprosthetic capsule formation was performed by 2 independent investigators in a double-blind manner. RESULTS: An analysis of the studies showed that the inner synovia metaplasia and the infiltration by inflammatory cells such as lymphocytes, histiocytes, plasma cells and granulocytes are of crucial importance in the development of a fibrotic capsule. The occurrence of these factors correlated significantly with each other and influenced also significantly the capsule architecture depending on implant surface. An adjustment of the existing Wilflingseder classification system was evaluated. The current rating system contains the following parameters: capsule thickness and cell layers of the capsule, the thickness of the inner synovial metaplasia, collagen structure, presence of histiocytes and the incidence of inflammatory cells. According to this classification, titanium-coated implants show an advantage in terms of the formation of capsular contracture. CONCLUSION: In 1974 Wilflingseder et al. developed a classification system for capsular contracture which is no longer appropriate, since current histological and immunohistochemical findings are not mentioned. Our study presents a new system which includes the latest insights into the development of capsular contracture and provides an objective classification of histological changes. Furthermore, we were able to show that titanium-coated implants are a promising approach in the reduction of capsular contracture.

[Histological and immunohistochemical investigations with capsular contracture after breast augmentation with smooth silicone gel implants]. / Histologische und immunhistochemische Untersuchungen bei Kapselkontraktur nach glatten Brustimplantaten.

INTRODUCTION: A prospective study was performed to analyse the cellular and molecular composition of fibrous capsules around silicone breast implants. The necessity of an exact histological classification for comparing objectively the different findings of capsular contracture is shown. PATIENTS AND METHODS: The prospective study (investigation time 1/2003 to 6/2005) included 24 female patients (average age: 40+/-12 years) with contracture after bilateral cosmetic breast augmentation with smooth silicone gel implants (Mentor). In each patient the baker score was determined preoperatively. Samples of capsular tissue from all patients were evaluated histologically and immunohistochemically and classified according to the histological classification introduced by Wilflingseder and co-workers. RESULTS: All capsules showed the same basic histological structure with a three-layer composition. For the correlation analysis we had to exclude one patient with repeated implant change. There was no correlation between the patient's age, time of implantation, length of implant period, and capsular contracture. Greater amounts of silicone particles were associated with increased degrees of capsular contracture (Baker: r = 0.687, n = 23, p < or = 0.001; Wilflingseder: r = 0.784, n = 23, p < or = 0.001). High silicone amounts were associated with an increased local inflammation (r = 0.489, n = 23, p , 0.05). A moderate to severe local inflammation was found in 23 patients (95.8%). In summary, there was a positive correlation (r = 0.797, n = 23; p , or = 0.001) between the clinical classification (Baker score I to IV) and the histological classification (Wilflingseder score I to IV). CONCLUSIONS: We demonstrated in our study, in spite of using implants with high gel cohesiveness (fourth generation), the presence of vacuolated macrophages with microcystic structures containing silicone and silicone particles in the capsular tissue. Greater capsular thickness was associated with an increased number of silicone particles ans silicone-loaded macrophages in the peri-implant capsule. The histological classification introduced by Wilflingseder and co-workers takes into consideration this pathogenetic mechanism of inflammatory reaction which seems to be one of the major key factors in the development of capsular contracture.

Proposal for a histopathological consensus classification of the periprosthetic interface membrane.

AIMS: The introduction of clearly defined histopathological criteria for a standardised evaluation of the periprosthetic membrane, which can appear in cases of total joint arthroplasty revision surgery. METHODS: Based on histomorphological criteria, four types of periprosthetic membrane were defined: wear particle induced type (detection of foreign body particles; macrophages and multinucleated giant cells occupy at least 20% of the area; type I); infectious type (granulation tissue with neutrophilic granulocytes, plasma cells and few, if any, wear particles; type II); combined type (aspects of type I and type II occur simultaneously; type III); and indeterminate type (neither criteria for type I nor type II are fulfilled; type IV). The periprosthetic membranes of 370 patients (217 women, 153 men; mean age 67.6 years, mean period until revision surgery 7.4 years) were analysed according to the defined criteria. RESULTS: Frequency of histopathological membrane types was: type I 54.3%, type II 19.7%, type III 5.4%, type IV 15.4%, and not assessable 5.1%. The mean period between primary arthroplasty and revision surgery was 10.1 years for type I, 3.2 years for type II, 4.5 years for type III and 5.4 years for type IV. The correlation between histopathological and microbiological diagnosis was high (89.7%), and the inter-observer reproducibility sufficient (85%). CONCLUSION: The classification proposed enables standardised typing of periprosthetic membranes and may serve as a tool for further research on the pathogenesis of the loosening of total joint replacement. The study highlights the importance of non-infectious, non-particle induced loosening of prosthetic devices in orthopaedic surgery (membrane type IV), which was observed in 15.4% of patients.

Reacción del tejido subcutáneo de rata a implantes de tres tipos de gutapercha empleados en sistemas de gutapercha termoplastificada / Rat connective tissue reaction to three types of gutta-percha implants employed in thermoplasticized gutta-percha systems

El propósito del presente estudio fue analizar la reacción ocurrida en el tejido conectivo de ratas, luego de la implantación de tres tipos de gutapercha utilizada en sistemas de gutapercha termoplastificada Obtura II, Thermafil y JS Quickfill. Se utilizaron 30 ratas en grupos de 15. Los animales fueron sacrificados luego de 14 y 84 días y los cortes coloreados con hematoxilina-eosina. La reacción producida por los materiales se evaluó histológicamente. Los implantes de las tres marcas de gutapercha analizadas fueron bien tolerados por el tejido conectivo en los dos períodos evaluados

Diagnostico de la Leishmaniasis mediante PCR en el departamento de La Paz / Diagnose of the leishmaniasis by means of PCR in the department of La Paz

La Leishmaniasis es un importante problema de Salud Publica presente en todas las zonas tropicales y subtropicales del mundo. En Boliviaseestima 1.800 casos nuevos anualmente> Los metodos convencionales para el diagnostico de la Leishmaniasis tiene limitaciones, las alternativas basadas en el estudio de la ADN han dado unas gran espectativa en tecnicas como Reaccion en Cadena de la Polimerasa PCR, La cual puede detectar diferentes complejos de Leismaniasis presentes en el Nuevo Mundo y Europa. En el presente trabajo se ha utilizado la tecnica de la PCR, como una nueva alternativa para el diagnostico de la Leishmaniasis. Se utilizaron cebadores que amplifican un segmento de 70pb del ADN de kinetplasto de Leishmaniasis braziliensis. Se analizaron diferentes tipos de muestras para la busqueda de parasitos a nivel local o sistemica en funcion al estado de la lesion que presento el paciente. Los resultados reportados nos permiten observar que para el estudio de pacientes con lesion cutanea activa, las muestras en la que se detecto rapidamente el parasito son: el aspirado de la lesion encontrando en un 45 porciento de los pacientes y las celulas mononucleares de sangre periferica con un 40 porciento de positividad mediante el PCR. En pacientes con lesiones mucosas activas, las muestras donde se identificaron al parasito fueron: los aspirados de la lesion con un 60 porciento. Finalmente aquellos pacientes con lesiones cicatrizadas de origen mucoso o cutaneo, el suero fue la muestra mas representativa en relacion a las celulas mononucleares con un 8 porciento de posibilidad al PCR

Biocompatibility of two apatite cements.

Biocompatibility and osteogenic potential of two calcium phosphate cements (G-5 and G-6) and Super-EBA were investigated by subcutaneous and intraosseous implantation in 90 rats. Reactions were studied microscopically at 15, 30, and 60 days after implantation. Super-EBA was well tolerated by both soft and hard tissues. G-5 was highly biocompatible with resorption and bone replacement at intraosseous implantation sites. G-6 promoted moderate inflammation and a foreign body giant cell response over the 60-day study period. None of the materials elicited osteogenesis or dystrophic calcification at the subcutaneous implantation sites.

[Local foreign body reactions to biodegradable implants. A classification]. / Lokale Fremdkörperreaktionen auf biodegradierbare Implantate. Eine Klassifikation.

Biodegradable implants are increasingly used in orthopedic and trauma surgery. Many different implants consisting of different biodegradable polymers are currently available. Different factors contribute to the biocompatibility of these implants, and local foreign-body reactions remain a matter of concern. Therefore, it is mandatory to document and compare the tissue reactions caused by various biodegradable implants in experimental or clinical studies. We have developed a standardized system of classification based on our previous experimental and clinical observations. Foreign-body reactions are differentiated into osteolysis (0-0 to 0-4), extra-articular (EA-0 to EA-4) and intraarticular (IA-0 to A-4) soft-tissue reactions.

[Testing tissue reactivity to surgical sutures using a personal point method]. / Badanie odczynu tkanek na nici chirurgiczne z zastosowaniem wlasnej metody punktowej.

In the Institution of Experimental and Biomaterial Research Surgery of Medical Academy in Wroclaw works on biological methods of estimation of different biomaterials including, first of all, surgical threads have been carried out for 30 years. The purpose of this work is to define the local biological reaction on the implanted absorptive and non-absorptive surgical threads. The present estimation of reactivity of surgical threads depended on a description of a great number of histological samples and on observation of numerous microscopic fields for each tested thread. It required long and tiring descriptions the analysis of which was made difficult and often led to non-objective conclusions. The presented punctual system depends on observation of the field of vision in a biological microscope which includes transverse cross-section of the implanted thread together with the surrounding tissues. The estimation of the histological samples in magnification of 45 times allows to define the range of infiltration of tissues with inflammatory cells in comparison with the diameter of the implanted thread. Observations in magnification 120 times allow to differentiate cells included in non-specific inflammatory process. The worked put punctual system enables to define the level of tissue reaction on the basis of uniform criteria.

Effects of biostability and morphology on host response of polyurethane-based soft tissue implants.

Polyurethane has been found to be one of the most successful polymers for soft tissue applications. We have investigated the effect of material biostability and morphology on the host response of polyurethane-based soft tissue implants in rabbits. The polyurethane containing allophanate linkage was prepared by using hexamethylene diisocyanate, polypropylene glycol (400) and 1,4-butane diol. Biuret-based biostable polyurethanes were prepared by using hexamethylene diisocyanate, polytetramethylene glycol and trimethylol propane and water. Samples of circular button and rectangular specimens were implanted subcutaneously in rabbits in the paravertebral region for a post-implantation period of 9 months. Relatively larger polyurethane samples with different morphology elicit a varied tissue response with our candidate polyurethane materials. A favorable tissue response was observed with rectangularly shaped thin polyurethane. Giant cell reaction, absence of fibrous tissue encapsulation and degradation were noticed for the rectangular smooth samples at the end of post-implantation period of 9 months. No malignant changes were noticed in any of these samples.