Comparação de resultado estético em cicatrizes com uso de fios cirúrgicos e Prineo® / Comparison between surgical sutures and Prineo® in terms of esthetic result and scar formation

Introdução: Cicatrização de ferida é um processo bem organizado que tem como finalidade a reparação tecidual completa. Colas e adesivos tópicos oferecem uma alternativa não invasiva, de retirada fácil e espontânea; boa força tênsil; menor tempo de aplicação, sendo o Prineo® uma cola adesiva associada a uma malha de poliéster aplicados sobre a ferida. Método: Trata-se de um estudo transversal retrospectivo com análise de 101 procedimentos cirúrgicos no período de 2012 a 2014, nos quais a síntese da ferida operatória ocorreu com fios cirúrgicos de náilon ou Prineo®, sendo aplicada análise estatística. Resultados: Neste estudo, seis pacientes apresentaram dermatite de contato ao uso do Prineo® com significância estatística (p = 0,042). O uso desse sistema diminuiu a taxa de alargamento cicatricial (p < 0,05). O presente trabalho não apresentou diferença estatística (p = 0,068) na qualidade da cicatriz entre os pacientes que utilizaram Prineo® em relação ao grupo controle, demonstrando que em ambos os grupos o resultado cicatricial foi de excelente (87%) a bom (27%) na sua maioria. Conclusão: Conclui-se no estudo que os pacientes que utilizaram o sistema de octil-2-cianocrilato associado a malha, Prineo®, apresentaram menores índices de alargamento cicatricial, dependentes de uma espessura de derme satisfatória, e maiores taxas de dermatites por contato em relação àqueles em que a ferida foi encerrada com fios cirúrgicos. Os dois grupos demonstraram qualidades cicatriciais excelentes a bons, sem diferença estatística em tais resultados estéticos cicatriciais.

Introduction: Wound healing is a well-organized, directed process of tissue repair. The process can be expedited using topical glues and adhesives, which offer a non-invasive, easily removable alternative to suturing. Furthermore, such products have good tensile strength and involve lower application time. In particular, the Prineo® adhesive is applied to a polyester mesh that covers the wound. Method: We carried out a retrospective, cross-sectional study, with subsequent statistical analysis , involving 101 surgical procedures in which wound closure was performed using either nylon sutures or Prineo®. All the procedures were performed between 2012 and 2014. Results: Six patients had contact dermatitis after Prineo® was used, with statistical significance (p = 0.042). Furthermore, Prineo® decreased the rate of scar enlargement (p < 0.05) . There was no statistical difference between the Prineo® and suture groups in terms of scar quality (p = 0.068); in both groups, the scar result was mostly excellent (87 %) to good (27%). Conclusion: Patients whose wounds were closed using Prineo® a system involving octyl-2-cyanoacrylate and an associated polyester mesh displayed lower rates of scar enlargement, which depended on whether the thickness of the dermis was satisfactory. However, the same patients had higher rates of contact dermatitis than those whose wounds were closed using surgical sutures. Both groups showed excellent to good scar quality, with no significant difference in terms of esthetic scar results.

Estudo comparativo entre etilcianoacrilato e sutura intradérmica no fechamento de excisões cutâneas / Comparative study of the use of ethyl cyanoacrylate adhesive and intracutaneous suture for cutaneous excision closure

INTRODUÇÃO: As vantagens dos cianoacrilatos em síntese cutânea têm sido sobejamente demonstradas na literatura. Entretanto, esses produtos têm sido subutilizados no Brasil, em decorrência dos elevados custos do octilcianoacrilato. Ademais, a forma mais economicamente acessível, etilcianoacrilato, tem sido pouco estudada como adesivo cutâneo. O objetivo deste estudo foi avaliar a eficiência do etilcianoacrilato na síntese de excisões cutâneas. MÉTODO: Estudo retrospectivo realizado em pacientes portadores de lesões cutâneas superficiais submetidos a excisão elíptica e reparo por fechamento primário. As excisões foram fechadas por meio de suturas profundas relaxadoras e, na superfície da pele, foi utilizado etilcianoacrilato (grupo caso - GCa) ou sutura intradérmica (grupo gontrole - GCo). RESULTADOS: Foram encontrados 33 pacientes portadores de 43 lesões cutâneas (GCa = 20 excisões; GCo = 23 excisões). Cicatrizes inestéticas (GCa = 20 por cento; GCo = 48 por cento), irritação ocular (GCa = 15 por cento; GCo = 0), deiscência (GCa = 5 por cento; GCo = 0), infecção (GCa = 0; GCo = 4,3 por cento) e dermatite de contato (GCa = 0; GCo = 4,3 por cento) foram os problemas encontrados. Os resultados cosméticos foram considerados satisfatórios na maioria das excisões (GCa = 100 por cento, GCO = 95,7 por cento). CONCLUSÕES: O etilcianoacrilato foi adequadamente tolerado neste grupo de estudo, sem induzir necrose, reações alérgicas ou infecções, apresentando diversas vantagens de uso em relação à sutura, incluindo reduzido índice de complicações e grande satisfação dos pacientes.

BACKGROUND: The advantages of cyanoacrylates in cutaneous wound closure have been widely demonstrated in the literature. However, these products have not been widely used in Brazil due to the high costs of octyl cyanoacrylates. Moreover, there have been only a few studies on the most affordable product, ethyl cyanoacrylate, as a cutaneous adhesive. The objective of this study was to evaluate the efficacy of ethyl cyanoacrylate in cutaneous excision repair. METHODS: A retrospective study conducted in patients with superficial skin lesions who underwent elliptical excision and repair by primary closure. The excisions were closed using deep relaxing sutures and either ethyl cyanoacrylate (case group; CaG) or intradermal suture (control group; CoG) on the skin surface. RESULTS: Thirty-three patients were identified with 43 cutaneous lesions (CaG, n = 20; CoG, n = 23). Unsightly scars (CaG = 20 percent; CoG = 48 percent), eye irritation (CaG = 15 percent; CoG = 0), dehiscence (CaG = 5 percent; CoG = 0), infection (CaG = 0; CoG = 4.3 percent), and contact dermatitis (CaG = 0; CoG = 4.3 percent) were the problems observed. The cosmetic results were satisfactory in almost all excisions (CaG = 100 percent; CoG = 95.7 percent). CONCLUSIONS: Ethyl cyanoacrylate was adequately tolerated in this study group, with no necrosis, allergic reactions, or infections. Ethyl cyanoacrylate presented several advantages over suture use, including low complication rates and high patient satisfaction.

HPLC analysis of HEMA released from two different adhesive systems.

OBJECTIVES: The aim of this study was to evaluate in vitro elution of 2-Hydroxyethyl methacrylate (HEMA) from two different adhesive systems, used in two dual polymerized resin cements for bonding of ceramic restoration by high performance liquid chromatography (HPLC). METHODS: Twenty freshly extracted caries and restoration free molar teeth used in this study. Standardized Class I preparations were prepared in all teeth. A lithium disilicate based (IPS Empress Esthetic; Ivoclar) ceramic inlays were cemented with one of the dual polymerized resin cements (RelyX ARC; 3M ESPE or Nexus 2; Kerr) that have two different adhesive systems (Single Bond; 3M ESPE, Optibond Solo Plus; Kerr). After cementation, specimens were stored in 75% ethanol solution. HPLC was used to analyze the amount of HEMA in the solution (after 10 min, 1 h, 24 h, 3, 7, 14, and 21 days). Two-way analysis of variance and Tukey HSD tests were used to evaluate the results (p < 0.05). RESULTS: There were statistically significant differences between adhesive systems according to the amount of released HEMA (p < 0.01) and also among time periods (p < 0.01). The amount of HEMA eluted from Optibond Solo Plus was significantly higher than Single Bond. The total amount of monomers was the highest after 21 days (p < 0.01). CONCLUSIONS: In the case of adhesive systems, Optibond Solo Plus showed the highest amount of HEMA. The amount of HEMA eluted from adhesive systems influenced by the time.

Transdentinal diffusion and cytotoxicity of self-etching adhesive systems.

OBJECTIVE: To evaluated the transdentinal diffusion and subsequent cytotoxicity of self-etching adhesives on odontoblast-like cells. MATERIALS AND METHODS: Sixty dentin disks (0.4-mm thick) were produced from human molars and divided into six groups (n = 10). The dentin disks were placed in in vitro pulp chambers where MDPC-23 cells were planted on 0.28 cm(2) of exposed dentin on the pulpal side. The adhesives Clearfil SE Bond (CSE), Clearfil Protect Bond (CPB), Adper Prompt (PR), and Xeno III (XE) were applied on the occlusal side. Single Bond (SB) was used as positive and phosphate buffer solution (PBS) as negative control. The cytotoxicity was measured by MTT assay and cell characteristics were assessed by SEM. The transdentinal diffusion was qualified by GC/MS. RESULTS: Kruskal-Wallis and Mann-Whitney tests demonstrated a significant difference among the adhesives and PBS. Cellular viability reduction promoted by the self-etching systems was lower than that of SB (53.1%), except for CSE. Cell metabolism was reduced in 47.8%, 42.1%, 28.0%, and 46.5% for CSE, CPB, PR, and XE, respectively. HEMA was identified as the main diffused component. CONCLUSION: Components from all investigated self-etching adhesive systems were able to diffuse through the dentin resulting in significant reduction of the cellular metabolism.

Comparative study of suture and in skin closure of rats / Estudo comparativo entre sutura e cianoacrilatos no fechamento de pele de ratos

PURPOSE: To compare the biocompatibility of ethyl-cyanoacrylate (ECA) and octylcyanoacrylate (OCA) wound closures to sutures in rat skin. METHODS: Twenty-four male Wistar rats were subjected to three incisions which were closed using ECA, OCA or sutures . Rats were divided into four groups which received biopsies on the 3rd, 7th, 14th or 21st post-operative days. Necrosis, inflammation, dermatitis, infection, dehiscence, cicatricial enlargement and costs were examined; the histopathology evaluated was epithelialization, deep openings, foreign substance reaction, residues of synthesis material, fibrosis, inflammation, dehiscence and necrosis. RESULTS: The tissue adhesives presented the largest dehiscence levels, and ECA the lowest cost while the other measures were similar. Regarding histopathology, deep openings were more common with OCA and granulomas were most frequently obtained with ECA. The two tissue adhesives produces less inflammation than the inicial suture from post-operative day 7, while ECA and OCA cause similar inflammatory reactions. ECA did not differ significantly from OCA and sutures on other measures. CONCLUSION: ECA was well tolerated in this study and did not induce necrosis, allergic reactions or infections, presenting several advantages in relation to OCA and sutures, including lower costs and fewer complications.

OBJETIVO: Investigar a biocompatibilidade do etil-cianoacrilato (ECA) em fechamento de pele em ratos comparativamente ao octil-cianoacrilato (OCA) e à sutura. MÉTODOS: Rattus norvegicus albinus (n=24) foram submetidos a três incisões, cada uma fechada por um dos métodos de síntese estudados. Quatro grupos (n=6) foram feitos, conforme o dia pós-operatório (DPO) em que foram eutanasiados: 3DPO, 7DPO,14DPO e 21DPO. Necrose, edema, eritema, dermatite, infecção, deiscência, alargamento cicatricial e custos foram os itens examinados; histopatologicamente avaliou-se epitelização, abertura profunda, reação de corpo estranho, resíduos de material de síntese, fibrose, reação inflamatória, deiscência e necrose. RESULTADOS: Os adesivos apresentaram os maiores níveis de deiscências, e o ECA o custo mais baixo; nos demais itens, não houve diferenças. Histopatologia: A abertura profunda foi mais comum com o OCA; ECA foi o material mais encontrado em granulomas; os adesivos foram mais brandos que a sutura a partir do 7º DPO no quesito inflamação, enquanto que o ECA causou uma reação similar ao OCA; nos outros itens, ECA não apresentou diferença importante em relação ao OCA e à sutura. CONCLUSÃO: O ECA foi bem tolerado neste grupo de estudo, sem induzir necrose, reações alérgicas e infecção, apresentando diversas vantagens de uso em relação ao OCA e à sutura.

Mucoadhesive, thermosensitive, prolonged-release vaginal gel for clotrimazole:beta-cyclodextrin complex.

The purpose of this study was to achieve a better therapeutic efficacy and patient compliance in the treatment for vaginitis. Clotrimazole (1%) has been formulated in a vaginal gel using the thermosensitive polymer Pluronic F127 (20%) together with mucoadhesive polymers such as Carbopol 934 and hydroxypropylmethylcellulose (0.2% for both). To increase its aqueous solubility, clotrimazole was incorporated as its inclusion complex with 1:1 molar ratio with beta-cyclodextrin. The inclusion complex was thoroughly characterized using various techniques, including 1H NMR spectroscopy, FT IR spectrophotometry, differential scanning calorimetry, scanning electron microscopy, phase solubility studies, and determination of stability constant (k(1:1)). The gelation temperature and rheological behavior of different formulations at varying temperatures were measured. In vitro release profiles of the gels were determined in pH 5.5 citrate buffer. It was observed that complexation with cyclodextrin slowed down the release of clotrimazole considerably. Carbopol 934, on the other hand, was found to interact with beta-cyclodextrin, inducing precipitation. As far as rheological properties are concerned, thermosensitive in situ gelling was obtained with formulations containing drug:cyclodextrin complex rather than with free drug. Thus, the optimum formulation for a controlled-release thermosensitive and mucoadhesive vaginal gel was determined to be clotrimazole:beta-cyclodextrin 1% with 0.2% hydroxypropylmethylcellulose in Pluronic F127 gel (20%) providing continuous and prolonged release of active material above MIC values.

Biochemical characterization of autologous fibrin sealants produced by CryoSeal and Vivostat in comparison to the homologous fibrin sealant product Tissucol/Tisseel.

Different principles for production of "autologous fibrin sealant" have been established, and commercial devices employing these methods are nowadays available and used in clinical routine. Users might anticipate for these autologous fibrin sealants features comparable to commercial homologous fibrin sealants, used in surgical routine for many years. However, only little is known about biochemical properties, formation, cross-linking and stability of fibrin sealant clots produced for autologous use with the aid of commercially available devices. We have investigated protein composition, formation and stability of clots obtained from autologuous fibrin sealants produced with commercially available devices (CryoSeal and Vivostat) and compared these parameters to those of the industrially produced homologous fibrin sealant Tissucol/Tisseel. The CryoSeal product is a mixture of many plasma proteins; the Vivostat product and Tissucol/Tisseel appear as comparatively pure plasma derivatives. The products differ in their protein composition and concentrations, including their concentration in fibrin. Significant fibrin alpha and gamma-chain cross-linking by FXIIIa occurs only in Tissucol/Tisseel clots. In test tubes CryoSeal and Vivostat (tranexamic acid-free formulation) fibrin clots liquefy within 1-2 days, but Vivostat (tranexamic acid containing formulation) clots were stable for 4 days and showed partial liquefaction after 5 days. Tissucol/Tisseel clots, containing the protease inhibitor aprotinin, appeared unchanged over the observation period of 5 days. In an in vitro model mimicking in vivo conditions (diffusion of protease inhibitors and proteolytic digestion) clot liquefaction occurs at day 1 for all autologous fibrin sealants clots, with an observable delay for the tranexamic acid containing Vivostat, and day 5 for Tissucol/Tisseel clots. Characterization of the CryoSeal and Vivostat fibrin sealants and Tissucol/Tisseel and their performance show a clear difference in biochemical properties.

Formulation and in vitro evaluation of prednisolone buccoadhesive tablets.

In this research, the effect of mucoadhesive polymers such as hydroxyl propyl methyl cellulose (HPMC) with viscosity grade 60 and 500 mPas, sodium carboxy methyl cellulose (NaCMC) and carbopol 934 (Cp 934) alone or in combination with each other on the release profile of prednisolone was studied and mucoadhesion strength of these buccoadhesive formulations was evaluated. The results showed that the release of prednisolone from HPMC with viscosity grade 60 mPas and Cp 934 alone was fast and their mucoadhesion strengths was low. On the other hand, the release rates of prednisolone from the HPMC viscosity grade 500 mPas and NaCMC and mucoadhesion strengths were moderate and suitable. The results showed that with different blends of HPMC viscosity grade 500 mPas or NaCMC and Cp 934 with increasing in HPMC or NaCMC/Cp 934 ratio a remarkable decrease in the rate of drug release and an appreciable increase in the mucoadhesion strength was observed. Except from the formulations prepared with HPMC viscosity grade 60 and 500 mPas, other formulation had more fluctuations in release profiles and their kinetics of release were not fitted to zero order model.

In vitro and ex vivo intestinal tissue models to measure mucoadhesion of poly (methacrylate) and N-trimethylated chitosan polymers.

PURPOSE: The adhesion of a range of polymers based on poly(2-(dimethylamino-ethyl) methacrylate (pDMAEMA) was assessed using human mucus-secreting and non mucus-secreting intestinal cell monolayers, HT29-MTX-E12 (E12) and HT29 monolayers, as well as excised non-everted intestinal sacs from rats. Differentiation of mucoadhesion from bioadhesion was achieved by pre-treatment with the mucolytic agent, N-acetyl cysteine (NAC). Adherence of pDMAEMA polymers was compared to that obtained with the mucoadhesive, N-trimethylated chitosan (TMC). METHODS: The quantity of adherent coumarin 343-conjugated polymers to HT29, E12, and intestinal sacs was measured by fluorescence. Confocal laser scanning microscopy (CLSM), light microscopy, and fluorescent microscopy were used to provide direct evidence. Measurements of transepithelial electrical resistance (TEER), permeability to FITC-dextran 4000 (FD-4), and the release of lactate dehydrogenase (LDH) were used to assess potential cytotoxicity of polymers. RESULTS: Adherence of unquaternized and of 10%, 24%, and 32% methyl iodide-quaternized pDMAEMA polymers was measured in E12, HT29, and sacs. All pDMAEMA polymers showed significantly higher levels of adhesion to mucus (mucoadhesion) than to epithelium (bioadhesion). Colocalization of pDMAEMA with mucus was confirmed in E12 by microscopy. TMC showed equally high levels of mucoadhesion as unquaternized and 24% quaternized pDMAEMA, but displayed higher levels of bioadhesion. pDMAEMA-based polymers demonstrated lower levels of adherence to E12 and rat sacs in the presence of NAC, whereas adherence of TMC was unchanged. pDMAEMA significantly decreased the permeability of FD-4 across E12 monolayers and sacs and was less cytotoxic in E12 than in HT29. In contrast, TMC increased the permeability of FD-4 across E12 and sacs and was less cytotoxic in E12 than in HT29. CONCLUSIONS: Human mucus-producing E12 monolayers can be used to assess polymer mucoadhesion and give similar data to isolated rat intestinal sacs. pDMAEMA displayed similar levels of mucoadhesion and lower levels of bioadhesion than a chitosan derivative and it was not cytotoxic. pDMAEMA decreased FD-4 flux in the presence of mucus, whereas TMC increased it. The combination of mucus and methacrylate polymers appears to increase barrier function of the apical membrane.

Resistance and stability of a new method for bonding biological materials using sutures and biological adhesives.

The valve leaflets of cardiac bioprostheses are secured and shaped by sutures which, given their high degree of resistance and poor elasticity, have been implicated in the generation of stresses within the leaflets, contributing to the failure of the bioprostheses. Bioadhesives are bonding materials that have begun to be utilized in surgery, although there is a lack of experience in their use with inert tissues or bioprostheses. Tensile testing is performed until rupture in samples of calf pericardium, a biomaterial employed in the manufacture of bioprosthetic heart valve leaflets. One hundred and thirty-two trials are carried out in three types of samples: intact or control tissue (n = 12); samples transected and glued in an overlapping manner with a cyanoacrylate (n = 60); and samples transected, sewn with a commercially available suture material and reinforced at the suture holes with the same cyanoacrylate (n = 60). Seven days after their preparation, 12 samples from each group, including the controls, are subjected to tensile testing until rupture and the findings are compared. In the stability study, groups of 12 each of the remaining 48 glued and 48 sutured and glued samples underwent tensile testing until rupture on days 30, 60, 90, and 120, after their preparation. The results show that bonding with the adhesive provided a resistance ranging between 1.04 and 1.87 kg, probably insufficient for use in valve leaflets, but also afforded a high degree of elasticity. After 120 days, both the glued and the sutured and glued series show excellent elastic behavior, with no rigidity or hardening of the pericardium. These samples present reversible elongation, or strain, when they surpass their elastic limit at rupture. This finding may be due to a load concentration that is damaging to the pericardium, to the behavior of the tissue as an amorphous material, or perhaps to both circumstances. These results need to be confirmed in future studies as they may be of value in the design and manufacture of cardiac bioprostheses.

Uso de cola sintética em cirurgia oculoplástica / The use of sinthetic glue in oculoplastics surgery

Objetivo: Testar a praticidade do uso de cola sintética em cirurgia plástica ocular. Local: Oculistas Associados do Rio de Janeiro, Hospital das Clínicas de Teresópolis, Hospital de Ipanema, Hospital Naval Marcílio Dias. Método: vinte pacientes foram submetidos a diferentes tipos de cirurgia plástica ocular com substituiçäo da sutura de pele pelo uso de cola sintética. Säo analisados os resultados estéticos e expostas as indicaçöes e contra-indicaçöes. Resultados: Houve um caso de fibrose da cicatriz. Notou-se que com a curva de aprendizado o tempo para a aplicaçäo foi menor.Näo houve deiscência de sutura ou infecçäo em nenhum caso.

Uso da colagel na cirurgia da conjuntiva: estudo experimental / Use of colagel in conjunctival surgery: experimental study

Os autores estudaram reaçäo dos tecidos oculares produzida pela aplicaçäo da cola tecidual colagel (Cirumédica), com o intuito de avaliar a possibilidade da sua utilizaçäo na cirurgia de exerese do pterígeo com a técnica do transplante de conjuntiva. Doze coelhas foram submetidas a peritomia de base límbica com aplicaçäo de colagel sobre a esclera que foi recoberta pela conjuntiva. Três coelhas näo operadas compuseram o grupo controle. O sacrifício dos animais foi feito 3, 7, 15 e 30 dias após a cirurgia, procedendo-se a exenteraçäo orbitária e preparo do material para exame histológico. Após a inoculaçäo do adesivo, como intra-ocular, com predomínio de células polimorfonucleares. Com a evoluçäo, houve melhora aparente da inflamaçäo, com limitaçäo da reaçäo ao local da inoculaçäo; porém, a inflamaçäo de estruturas intra-oculares (irite, vitreite, coroidite) continuou, havendo necrose e perfuraçäo ocular próximo ao local da inoculaçäo em alguns animais. Pode-se concluir que a colagel näo se presta para o uso como adesivo tecidual nas cirurgias da conjuntiva

Solubility study of albumin solders for laser tissue-welding.

BACKGROUND/OBJECTIVE: Current albumin solders for tissue-welding are soluble in physiological fluids, prior to laser irradiation. These solders are therefore subjected to mechanical alterations, which can weaken the solder-tissue repair. In this study, an albumin solder (laser activated) was developed with low solubility and with the ability to retain (partially) its mechanical characteristics in saline solution. STUDY DESIGN/MATERIALS AND METHODS: Gauged protein samples of solder were immersed into 0.5 ml saline solution for fixed intervals of time. The solder samples contained four bovine serum albumin (BSA) concentrations: 56%, 66%, 70%, and 75% (by weight). A Bradford protein assay measured the BSA solubility of the solders. The 70% and 75% BSA solders were also used to weld in vitro Wistar rat intestine sections with a diode laser (lambda = 810 nm, power = 270 mW). RESULTS: The solubility of the 75% BSA solder was significantly decreased with respect to the other solders (Anova, P < 0.05). This solder also showed comparable weld strength (13 gm) to the 70% BSA solder. CONCLUSION: The 75% BSA solder strongly reduced the albumin solubility in saline solution, without affecting its tissue-welding properties.

Human albumin solders for clinical application during laser tissue welding.

BACKGROUND AND OBJECTIVE: Fifty percent human albumin solder significantly improves weld strength when compared to lower concentrations [Wright et al., ASLMS meeting, April, 1995]. We developed a method for preparing 50% human albumin that may be considered compatible for clinical applications. STUDY DESIGN/MATERIALS AND METHODS: Fifty percent human albumin solder was prepared from 25% commercially available human albumin using a lyophilization technique. Assessment of sterility, viscosity, pH, and peak absorption wavelength were performed. RESULTS: This report describes the methodology used to prepare a 50% human albumin solder that is compatible with clinical use. Maintenance of the structural integrity of the albumin was confirmed by polyacrylamide gel electrophoresis. CONCLUSION: This solder preparation can be used alone or with the addition of exogenous chromophores. The final product is sterile, incorporates viral free protocols, maintains high viscosity, and can be applied easily during open or laparoscopic procedures.

Oligomers with pendant isocyanate groups as tissue adhesives. I. Synthesis and characterization.

A series of methacrylate oligomers containing pendant isocyanate groups were synthesized by reacting 2-isocyanatoethyl methacrylate (IEM) and/or m-isopropenyl-alpha, alpha-dimethylbenzyl isocyanate (TMI) in ethoxyethyl acetate with methacrylates ranging from methyl to stearyl methacrylate or allyl-, cyclohexyl-, glycidyl-, i-bornyl-, or dicyclopentenyloxyethyl methacrylate. The oligomers which are stable at room temperature were characterized by IR for NCO, ester, and C = C groups and by their refractive indices. They have a small number of residual double bonds and a molecular weight low enough so that the compounds are liquids at room temperature and dissolve readily in esters and chlorinated hydrocarbons. HPLC showed no residual monomer. GPC and intrinsic viscosity of selected oligomers indicated a molecular weight range from 1400 to 2600. Isocyanate groups were determined titrimetrically and ranged from 15.9% to 5.1%. Concurrent studies have demonstrated that these oligomers bond strongly to hard and soft tissues. Thus, subject to their biocompatibility they could find many applications as tissue adhesives.

The use of fibrin glue in repair of peripheral nerves.

Gluing of nerves with histocompatible and resorbable materials offers a distinct advantage on suturing alone because results in clinical surgery are similar and often better. This method, when applied properly, allows a considerable gain of operative time, which we estimate to be 3-fold (ie, instead of taking 1 hour for grafting one nerve trunk, it takes 20 minutes). It does not represent a breakthrough in peripheral nerve surgery because it does not guarantee that each nerve fiber will be aligned with its own stump. Gross evaluation shows that the percentage of good results is increased by approximately 15 per cent. It must be stressed, however, that a portion of this improvement, difficult to evaluate, may be caused not by the method but by the experience we have gained over the years practicing nerve repair. The commercial fibrin glue is not yet released in the United States by the Food and Drug Administration; however, it seems, at the time of this writing, that this will be done by the first months of 1988.

[Basic and clinical studies on osteochondral fragment fixation using fibrin adhesive system (FAS) in cases of fracture].

The healing process of osteochondral fracture was studied experimentally and clinically, using fibrin adhesive system (FAS) containing highly concentrated and freeze-dried fibrinogen, thrombin and factor XIII. Osteochondral fractures were made in the femoral condyle of the rabbit. Most of the adhered fibrin was gradually absorbed at the fracture site and at the same time was replaced with granulation tissue containing abundant capillaries, fibroblasts and osteoblasts, by the 10th day. Complete fracture healing was achieved histologically in one month. Fifteen cases of intraarticular osteochondral fractures in the hand were treated with FAS clinically. Complete bony union was obtained in all cases at 3 to 6 weeks postoperatively. The range of motion was limited in 3 cases, but was excellent in the other 12 cases. From our experimental and clinical results, it appears that FAS may produce no obstructive effects in bony healing. Management of intraarticular osteochondral fixation would be much easier by using FAS than by the conventional fixation materials such as metal screws or K-wire.

Detection of cyanoacrylate tissue adhesives in histological sections.

Previous histological studies of cyanoacrylate in wound healing have all used Oil-Red-O staining of paraffin sections prepared by routine method. In the course of our studies we began to suspect that artifact was being introduced because of dissolution of cyanoacrylate during processing. Accordingly, biopsis of wounds sealed with cyanoacrylate and pieces of cyanoacrylate of a standard known dimension with no associated tissue were observed after every stage of histological preparation. It was observed that approximately 80% of the cyanoacrylate was lost at the deparaffinization in xylene stage. Accordingly, a number of solvents were tested, and it was found that petroleum ether could be used to remove paraffin completely without the loss of any of the cyanoacrylate from the specimen. This technique has been used to view the location and ultimate fate of cyanoacrylate applied to wounds and examined at different stages in healing process. It is concluded that previous histological studies of cyanoacrylate in wound healing have been inaccurate due to leaching out of most of the tissue adhesive during deparaffinization of the specimen.

[Surgical therapy of the dissection of the ascending aorta. Experience in the use of the G. R. F. biological glue]. / Sulla terapia chirurgica della dissecazione dell'aorta ascendente. Esperienza nell'impiego della colla biologica G.R.F.

Nine patients with dissecting aneurysm of the ascending aorta (type A dissection) were operated upon. Six cases had an acute dissection, whereas three cases had a chronic type of dissection. The ascending aorta was replaced with a Dacron tubular prosthesis after solidification of the external and the internal layers of the two aortic stumps using a G.R.F. biological glue. Early and late results as well as the possible complications during the post-operative course are reported. Furthermore the advantages in using the G.R.F. glue are discussed in details. They are mainly represented by the excellent solidification of the aortic stumps, by the possibility to correct the aortic regurgitation without valve replacement and particularly by a good hemostasis of the surgical sutures.