Cause Of Replacement Research Articles

Analysis of durability and replacement of vocal prostheses in total laryngectomy patients at a head and neck surgery referral center.

The use of tracheoesophageal prostheses has become the gold standard in vocal rehabilitation of patients undergoing total laryngectomy. However, this method also has limitations, such as the need for frequent replacement of prostheses due to leakage or other complications. We have designed a study to access the clinical profile of patients using tracheoesophageal prostheses as vocal rehabilitation after total laryngectomy and to determine the average rate of changes, as well as the main causes of prostheses replacement. A retrospective cohort study was performed based on patients who underwent rehabilitation with voice prostheses after total laryngectomy between 2008 and 2017. The sample consisted of 93 patients and 432 vocal prostheses replacement events. The median change of prostheses per patient was 210.25days, (range 57.33 to 651.50). The most frequent cause of prostheses replacement was leakage through the prostheses, 218 (50.46%). Lower level of education was associated to higher prostheses replacement rate. The results of this study show that the median of prostheses durability is higher than that presented in the literature, the main cause of replacement was protheses leakage and that low educational level is associated to higher replacement rate.

Effect of Different Repolishing Procedures on The Color Change of Alkasite

Objectives: An esthetic restoration with an unacceptable color is the main cause for replacement of anterior tooth restorations. The aim of this study is to evaluate the effect of repolishing on the color change of the new material group of alkasite after exposure to coffee solution. Materials and Methods: Alkasite material placed in Teflon molds with a diameter of 8 mm and a height of 2 mm was polymerized under the application of mylar strip and a total of 32 samples were obtained. The samples were randomly immersion into groups. Group R: Diamond grained polishing rubbers, Group D: Aluminum oxide discs are applied and the polishing process is completed. After the first color measurement was made, it was immersed in coffee and the measurement was repeated 1 week later. L was divided into two groups (n=8) and repolished with rubber (RR) and discs (RD). In the D group, re-polishing was done with rubber (DR) and disc (DD) and color measurements were repeated. Results were analyzed by using one-way ANOVA and Tukey test at 95% confidence interval. Results: The greatest color change (ΔE00) was in group R. At the end of seven days, similar color change values were found between the groups of R and D (p > 0.05). There is no difference between the RR and RD groups. Significantly less color change was observed in the DD group than in the RR and RD groups (p = .003, p = .042, respectively). Similarly, the DR group showed less color change than the RR group (p = .015). Conclusions: The color stability of the alkasite was affected by the polishing procedure. The repolishing process reduced the color change, but not at a clinically acceptable level.

Surgery after Failed Transcatheter Aortic Valve Implantation: Indications and Outcomes of a Concerning Condition.

Objectives: The number of transcatheter aortic valve implantations (TAVI) has increased enormously in recent decades. Transcatheter valve prosthesis failure and the requirement of conventional surgical replacement are expected to attract more focus in the near future. Indeed, given the scarcity of research in this field, the next decade will likely represent the beginning of a period of meaningful exploration of the degenerative changes that occur with transcatheter valves. The current study represents—through a series of consecutive cases—one of the first analyses of the underlying causes of TAVI failure, i.e., degenerative, functional and infective, followed by surgical aortic valve replacement (SAVR) and postoperative outcome. Methods: Between October 2008 and March 2021, 2098 TAVI procedures, including 1423 with transfemoral, 309 with transapical, and 366 with transaortic access, were performed in our institution. Among these, 0.5% (number(n) = 11) required acute SAVR (n = 6) within 7 days (n = 3) or later (n = 2), and were included in the study. Results: Valve stent dislocation was the most common cause of replacement (83%). Causes of replacement within 7 days after TAVI were multifactorial. In the later course, endocarditis was the sole indication for SAVR after TAVI. TAVI with transapical or transaortal approach had a higher EuroSCORE II (10.9 (7.2–35.3) vs. 3.5 (1.8–7.8)). Their 30-day mortality after surgical conversion was higher (67% vs. 20%), when compared to those who underwent a transfemoral procedure. The longest documented survival beyond 30 days was 58 months. Conclusions: The causes of SAVR after TAVI failure are multifactorial, and include biological, physical and infectious factors. An acceptable midterm prognosis may be expected in patients with physical causes when dislocation of the catheter prosthesis is observed; in such cases, emergency conversion is required. Conversion due to infection, as in cases of endocarditis, had the worst outcome. Prognosis after conversion due to degeneration is still problematic, due to a lack of autopsies and the recent history of prosthetic implantations.

P134410 YEARS EXPERIENCE WITH HEMODIALYSIS TUNNELED CATHETERS

Abstract Background and Aims A well functioning vascular access ( VA) is vital for hemodialysis (HD) patients. To date a native arteriovenous fistula ( NAVF) remains the gold standard but patients vascular characteristics are often not optimal for vascular surgery. A tunneled central venous catheter (tCVC) are becoming increasingly used as permanent dialysis access and are also competitive to NAVF for the easy and safe insertion tecnique. Our retrospective study observe, during a 10 years period, infection rate of tCVC, bacteriologic analysis and cause of removal. Method From January 2010 to December 2019, 176 tCVC were placed in 158 patients ( mean age 74 +/- 18) . All tCVC were inserted by nephrologist in internal giugular vein (IGV), subclavian vein (SV) and femoral vein (FV) using ultasonographic guide. Standards protocols, according to European Renal Best Practice (2010) detailing all aspects of preventive care were used. Each tCVC was followed until it was removed or until the end of the study. 62110 days was the follow up period. 143 tCVC wew placed in IGV ( 81,5%), 22 in FV ( 11,5 %) and 11 in SV (7%). The diagnosis of infection was based on clinical evidence and positive blood culture or positive exit site swab, with no sign of other infection site. We considered a tCVC disfunction in case of blood flow less than 250 ml/m'. Event rates were calculated per 1000 catheters days. Results Mean tCVC duration was 353 days. We observed a progressive increment in CVC prevalence during the observational period ( from 15% in 2010 to 39% in 2019). Catheter replacement recurred in 19 patients and the main cause of replacement was loss of patency ( 0,3 per 1000 catheter days). We observed 63 catheter related bloodstream infection (CRBI) and 71 exit site/tunnel infection (ESI/TI). Incidence for CRBI was 1 per 1000 catheter days and ESI/TI was 1,14 per 1000 catheter days. In CRBI the most common organism isolated were MRSA (40%) and MSSA (26%) . In ESI/TI the most common organism isolated was Staphilococcus epidermidis (39.5%) . We used systemic antibiotics, local therapy and lock therapy with a 93% resolution without removal. 12 tCVC were removed for recurrent CRBI ( 0,19 per 1000 catheter days). At the end of the observation 25 tCVC were still in use. Conclusion Our data showed an high survival rate of tCVC in hemodialysis patients. We observed CRBI and ESI/TI rates at the lower limits of the data reported in the literature. Infections were successfully treated conservately in most cases. Careful nursing protocol may reduced the frequency of infection and an early diagnosis can facilitate the rescue of the tCVC with systemic/lock therapy or local therapy. We consider in an elderly population with many comorbidities the use on tCVC recommended especially in patients with poor native peripheral vessels, in patients with steal syndrome high risk and also with a low life expectancy.

Synthesis of an anti-cariogenic experimental dental composite containing novel drug-decorated copper particles

Secondary caries is one of the most major cause for re-placement of dental composite restorations. Targeting the survival of cariogenic bacteria residing on the restoration surface may reduce this problem. The present study aims to evaluate the antibacterial potential as well as assess the physical and chemical properties of experimental dental composites containing novel drug-decorated copper particles (DDCP) as adjunct antibacterial filler particles. These were incorporated at concentrations of 0%, 0.5%, 0.10%, 0.20%, and 0.25% (w/w) into experimental composite consisting of methacrylate monomers and silanized silica fillers. RESULTS: Direct contact test revealed that the anti-cariogenic potential of experimental composites was more than the control groups. The cell viability assay showed no toxic effect on MC3T3-E1 cell lines in the MTT assay. The microhardness of experimental composites increased as the percentage of DDCP increased, however, the degree of cure was increased only up till the concentration of 0.20%. The release kinetics of the composites reveals that even after 28days there was a steady and slow release of copper particles signifying the sustained anti-cariogenic effect. CONCLUSION: The experimental composites have good anti-cariogenic potential, which was sustained for one month without any deleterious effect on the physical and chemical properties of resin dental composites.

Replacement of Cable Stays in Yonghe Bridge in Tianjin, China

Cable replacement is one of the most important approaches for retrofitting an existing cable‐stayed bridge. The Yonghe Bridge opened to traffic in 1987 and was the largest concrete cable‐stayed bridge in Asia at the time. After nearly 20 years in service, its stay‐cable system was completely replaced. The present paper details the key technical points of cable replacement in this bridge, including causes of replacement, cable replacement design, construction monitoring during replacement, and cable tension tuning after replacement. Based on the measurements during construction, the variation in structural condition indexes was thoroughly investigated, such as cable forces throughout the bridge, geometry profile of bridge deck, and tower horizontal displacements. The structural changes due to cable replacement were evaluated, and then, a relatively desirable scheme of cable adjustment was correspondingly put forward. The measured results showed that, influenced by the accumulated tolerances of cable forces during construction, cable replacement may often lead to a further deviation of structural condition. In this instance, cable adjustment is an effective compensation measure to improve the overall structural condition of the bridge. The practice of cable replacement in the Yonghe Bridge has provided some valuable experience or beneficial references for the similar retrofitting cases.

Favorable Trend of Implantable Cardioverter-Defibrillator Service Life in a Large Single-Nation Population: Insights From 10-Year Analysis of the Italian Implantable Cardioverter-Defibrillator Registry.

BackgroundImplantable cardioverter‐defibrillators (ICDs) are widely employed for the prevention of sudden cardiac death. Despite technological improvements, patients often need to undergo generator replacement, which entails the risk of periprocedural complications. Our aim was to estimate the service life of ICDs over a 10‐year interval and to assess the main causes of replacement on the basis of data from the National ICD Registry of the Italian Society of Arrhythmology and Cardiac Pacing (AIAC).Methods and ResultsThe registry includes data from over 400 hospitals in Italy. We included all patients who underwent device replacement from calendar years 2007 to 2016. The median service life of the ICDs and its trend over the years was estimated across the 3 types of devices (single‐chamber, dual‐chamber, cardiac resynchronization therapy defibrillator) and the indication to implantation. The causes of replacement were also analyzed. We included 29 158 records from 27 676 patients (80.9% men; mean age at device replacement 65.8±12.0 years). The median service life was 57.3 months (interquartile range 27.8 months). Over the years, service life showed an increasing trend. The majority of patients underwent elective replacement because of battery end of life, and over the years there was a significant reduction of replacement for recalls, erosion/infections, and cardiac resynchronization therapy upgrading.ConclusionsOur data from a large single‐nation population showed that the trend of ICD service life, independently from ICD type, indication, and settings, significantly improved over time. Moreover, there was a striking reduction of interventions for upgrading and infection/erosion. This favorable trend has important clinical, organizational, and financial implications.

Microstructural Changes during High Temperature Service of a Cobalt-Based Superalloy First Stage Nozzle

Superalloys are a group of alloys based on nickel, iron, or cobalt, which are used to operate at high temperatures (T> 540°C) and in situations involving very high stresses like in gas turbines, particularly in the manufacture of blades, nozzles, combustors, and discs. Besides keeping its high resistance to temperatures which may approach 85% of their melting temperature, these materials have excellent corrosion resistance and oxidation. However, after long service, these components undergo mechanical and microstructural degradation; the latter is considered a major cause for replacement of the main components of gas turbines. After certain operating time, these components are very expensive to replace, so the microstructural analysis is an important tool to determine the mode of microstructure degradation, residual lifetime estimation, and operating temperature and most important to determine the method of rehabilitation for extending its life. Microstructural analysis can avoid catastrophic failures and optimize the operating mode of the turbine. A case study is presented in this paper.

Hemodialysis tunneled central venous catheters: five-year outcome analysis.

Tunneled central venous catheters (tCVCs) are considered inferior to arteriovenous fistulas (AVFs) and grafts in all nephrology guidelines. However, they are being increasingly used as hemodialysis vascular access. The purpose of this study was to document the natural history of tCVCs and determine the rate and type of catheter replacement. This was a prospective study of 141 patients who underwent hemodialysis with tCVCs between January 2008 and December 2012. The patients used 154 tCVCs. Standard protocols about management of tCVCs, according to European Renal Best Practice, were well established. All catheters were inserted in the internal jugular vein. Criteria for catheter removal were persistent bloodstream infection, detection of an outbreak of catheter-related bloodstream (CRBS) infections, or catheter dysfunction. Event rates were calculated per 1,000 catheter days; tCVC cumulative survival was estimated by Kaplan-Meier analysis. Catheter replacement occurred in 15 patients (0.29 per 1,000 days); catheter dysfunction was the main cause of replacement (0.18 per 1,000 days), typically within 12 months of surgical insertion. A total of 53 CRBS events in 36 patients were identified (0.82 per 1,000 days); 17 organisms, most commonly Gram-positive pathogens, were isolated; 87% of CVC infections were treated by systemic antibiotics associated with lock therapy. tCVC cumulative survival was 91% at 1 year, 88% at 2 years and 85% at 4 years. Our data show a high survival rate of tCVCs in hemodialysis patients, with low incidence of catheter dysfunction and CRBS events. These data justify tCVC use for hemodialysis vascular access, also as first choice, especially in patients with exhausted peripheral access and limited life expectancy.

Effect of Temperatures on Polymerization Stress and Microleakage of Class V Composite Restorations

The loss of interfacial integrity was identified as one of the major causes for replacement of resin composite restorations. Preheating procedure has been proven to enhance flowability and adaptation of resin composites and increase their degree of conversion. The purpose of this study was to investigate polymerization contraction stress produced in resin composites after preheating to 37℃ and 60℃, and measure microleakage of Class V restorations restored with preheated composites. Three resin composites (GC Kalore, Gradia Direct X, Filtek Supreme XT) at room temperature, 37℃, and 60℃ were investigated. Maximum contraction stress of the composites (n = 5) was evaluated in a modified low-compliance device. Samples were light-cured for 40 seconds and the maximum force was recorded during 15 minutes. Calculations were done to adjust for the system’s compliance and obtain linear shrinkage values of composites. Data were analyzed by Multivariated Analysis of Variance (MANOVA) and Tukey’s test for multiple comparisons (α = 0.05). Seventy-two Class V cavities were prepared on the buccal surfaces of extracted premolars and divided into 9 groups. The teeth were restored with composites at 3 temperatures and were thermo-cycled between 5℃ and 55℃ with a one-minute dwell-time for 1000 cycles. The teeth were sealed with wax and nail vanish before placed in 0.5% toluidine blue dye for 24 hours. The teeth were embedded in self-curing resin and sectioned bucco-lingually with a slow-speed diamond saw, providing 3 sections per restoration. Microleakage was rated by two evaluators using a 0 - 4 ordinal scale at the occlusal and cervical margins under light microscope. Microleakage data were analyzed with Kruskal-Wallis ANOVA and Mann-Whitney U test (α = 0.05). Results indicate that preheating composites to 37℃ and 60℃ significantly increased polymerization contraction stress of composites (p 0.05). A significantly greater amount of leakage was found at the cervical margins (p 0.05). For all tested materials, preheating composites to 60℃ resulted in significantly less microleakage at the cervical margin.

Chirurgiczna rehabilitacja głosu chorych po laryngektomii całkowitej z zastosowaniem systemu Provox

Comparison the voice quality of patients after total laryngectomy using the Provox 2 voice prosthesis and patients with esophageal speech and to discuss difficulties and complications related with its implantation.The study group consists of 39 patients after total laryngectomy and Provox puncture. 36 patients underwent primary puncture, 3 patients - secondary puncture. 32 patients underwent radiotherapy. The time starting of speech learning was approx the 9th day after total laryngectomy and 1st-3th day after secondary implantation. The authors subjectively and objectively analyzed voice of 34 patients with fistular speech and it compared with esophageal speech of 10. The spectrograms analysis of the voice was based on Remacle's scale. The study showed juxtaposition of early and late complications of patients with voice prostheses.90% of patients (35 patients) learned the fistular speech. The speech was louder and more intelligible than esophageal voice in subjective estimation. The fistular voice had higher of mean volume (61,1 dB vs. 59 dB), mean longer maximum phonation time (9,5 s vs. 2,2 s), mean higher base frequency FO (108 Hz vs. 87Hz) and smaller variability of FO based on mean Jitter ratio (3,8% vs. 6,6%), mean Shimmer ratio (23,18% vs. 23,52%) and mean HPQ ratio (127,34 vs. 141,73) than esophageal voice in objective estimation. Mean range of frequency of the speech was smaller but it was in higher frequencies. The most frequent type of spectrogram was 3th type in experimental group and 2nd type in control group. The mean lifetime of prostheses was 295 days. The most common cause of replacement of the prosthesis was leakage associated with mycosis infection (26 cases). Early complications were observed. The most frequent of them was infection around the fistula during supplementary radiotherapy (7 cases after primary puncture). The most frequent of later complications was widening of fistula and leakage around prosthesis (4 cases).Rehabilitation of patients after total laryngectomy is better using Provox system than learning esophageal speech (according to voice quality aspect). Using of voice prostheses in patients after total laryngectomy can combine with appearance of complications.

LAND COVER DYNAMICS OF DIFFERENT TOPOGRAPHIC CONDITIONS IN BEIJING

Topographic conditions play an important role in controlling land cover dynamic processes. In this study, remotely sensed data and geographic information system were applied to analyze the changes in land cover along topographic gradients from 1978 to 2001 in Beijing, a rapidly urbanized mega city in China. The study was based on five periods of land cover maps derived from remotely sensed data, Landsat MSS for 1978, Landsat TM for 1984, 1992, 1996 and 2001, and digital elevation model (DEM) derived from a 1: 250 000 topographic map. The entire area was divided into 10 land cover types: conifer forest, broadleaf forest, mixed forest, shrub, brushwood, meadow, farmland, built_up, water body and bare land. The results are summarized below. 1) Shrub, forest, farmland and built_up consist of the main land cover types of the Beijing area. The most significant land cover change from 1978 to 2001 was a decrease in farmland and an expansion of built_up areas. Farmland decreased from 6 354 to 3 813 km~2 over the 23 years, while built_up areas increased from 421 to 2 642 km~2. Forest cover increased from 17.2% to 24.7% of the total area. The conversion matrix analysis indicated that transformation of farmland to built_up area was the most significant process and afforestation was the primary cause of replacement of shrub to forest. 2) Topographic conditions are of great importance to the distribution of land cover types and the process of land cover changes. Elevation has a strong impact on the distribution of land cover types. The area below 100 m mostly consisted of farmland and built_up areas, and the area above 100 m is mainly covered by shrub and forest. Shrub has a maximum frequency in elevations between 100 and 1 000 m, while forests were dominant in areas above 800 m. According to the analysis of land cover changes in different elevation ranges, the greatest change was below 100 m due to urbanization. The main land cover change process that occurred above 100 m was transformation from shrub to forest. This result was constant with the vertical change of natural vegetation distribution in Beijing. 3) Slope has a large influence on the distribution of land cover types. Farmland and built_up areas are distributed primarily in flat areas, while shrub and forest occupy steeper lands as compared with other land cover types. Forest frequency increased with increasing slope. Land cover change processes differed with slope gradients. In the plain area, land cover change occurred as the result of urbanization. With increasing slope gradients, afforestation, which converted shrub to forest, was the primary land cover change process.

Postlaryngectomy Voice Restoration Using a Voice Prosthesis: A Single Institution's Ten-Year Experience

We describe the speech rehabilitation outcome of patients treated with total laryngectomy or total laryngopharyngectomy and insertion of Provox voice prostheses (Atos Medical AB, Hörby, Sweden) at the Helsinki University Central Hospital. We performed a retrospective chart review of 95 patients (88 men and 7 women; mean age, 63.5 years) who underwent insertion of a voice prosthesis in the period 1992 to 2002. Eighty-one percent (77/95) of the patients underwent a primary prosthesis insertion at the time of laryngectomy. A head and neck surgeon, a laryngologist, and a speech therapist rated the long-term tracheoesophageal speech of 78% (74/95) of the patients as good or average. The main causes for replacement of the device were obstruction, leakage or inadequate size of the prosthesis, and granulation or leakage around the fistula. According to our 10-year experience, use of the Provox prosthesis is an effective method of postlaryngectomy voice rehabilitation, and it continues to be our preferred method of voice restoration in the majority of cases.

Resin restorations: leakage, bacteria, pulp

Through the development of composite resin materials, the acid-etch technique and dentin adhesives, dentists can now complete perfect and permanent dental restorations--restorations with a color and shape approximating the natural tooth, with perfect marginal adaptation, and no harmful effects to the surrounding tissues, including the dental pulp. However, newer cross-sectional studies indicate that marginal defects are still the main cause of replacement of resin restorations, and that their clinical durability is shorter than that of other types. Moreover, there is no doubt that gap preventive treatments can intensify pulpal reactions to resin restorations if bacterial leakage occurs. The present thesis is based on nine previously published studies (I-IX). The aims of the studies were: to examine the possibilities of minimizing the occurrence of bacterial leakage around resin restorations through the use of various gap preventive procedures, to extend our understanding of their mode of action, and to investigate the pulpal reactions associated with restorations with and without bacterial leakage. The results of earlier research are reviewed, as well as the various methods for registration of gap occurrence around restorations. Studies I-IX are described briefly and followed by a discussion of the results, a summary and some concluding remarks.

Reasons for Replacement of Long-Term Urethral Catheters: Implications for Randomized Trials

On any given day more than 100,000 nursing home patients have indwelling urethral catheters in place. We prospectively followed 47 such patients for almost 18 patient-years and observed 249 catheter replacements. The mean number of replacements per 100 days of catheterization was 3.1 (71% of the catheters were replaced within 30 days of insertion). Nonprescribed removal by the patient or nursing staff was the most frequent cause of replacement (43%), followed by leakage (33%) and obstruction (24%). Catheter replacements followed patient-specific patterns, with each reason for replacement being associated significantly with the reason for the prior replacement (p less than 0.001). To minimize the effect of patient-specific replacement patterns, studies of complications of catheterization that may be affected by catheter obstruction or replacement should use cross-over designs.

The gastrostomy button: a prospective assessment of safety, success, and spectrum of use

The gastrostomy button is a new, skin level, nonrefluxing, mushroom-tipped feeding device which can be used to replace conventional gastrostomy catheters. We have prospectively evaluated 31 consecutive patients managed with this appliance and our results show that the button can be successfully placed in 90% of cases without serious morbidity or mortality. The procedure is quick to perform, requires minimal intravenous sedation, and is well-suited to a broad range of socially active gastrostomy-dependent patients. Patients found the aesthetics, convenience, and independence of the low profile design attractive and no individual wished to return to the original method of feeding. Small and medium-sized buttons were easier to place than larger devices. Gastrocutaneous reflux through the appliance occurred in 11% of cases and was a common cause for replacement. Alert, ambulatory patients with an established gastrostomy and short or medium-sized gastrocutaneous fistulous tracts are ideal candidates for the button.

Adult male replacement inMacaca fascicularis of East Kalimantan, Indonesia

This report on wild-ranging crab-eating macaques in East Kalimantan, Indonesia, describes male replacements for the first time in this species. A replacement at the alpha rank by an immigrant adult male was seen in this multimale troop during each year of the 20-month field study. The data show considerable variation in the process and outcome of social change. Adult male immigrants contested the alpha rank, whereas subadult male immigrants did not. The first replacement took 2 days, whereas the second one took 1 month. In the first replacement four males and 10 other residents left the troop. In the second replacement one of the two adult males was successful in immigrating when he replaced the resident male of his alpha rank, but the deposed alpha male was not evicted from the troop. Existing models of the causes of replacement (such as high density or human disturbance) and of the causes of infanticide are not supported by these data. Infanticide by immigrating males was not observed despite the apparent presence of the postulated circumstances conducive to infanticide.

UCON Quenchant ‘A’ A New Quenching Fluid

Union Carbide Ltd., (8 Grafton Street, London, W.1.) have introduced a new heat treatment fluid known as UCON Quenchant ‘A’ which is said to have distinct advantages over conventional quenchants, emulsions, PVA solutions or water. This fire‐safe metal quenching medium is based on a unique principle and cooling rates can be varied by simple control of water dilutions and temperature. In some cases, it is said that this product can reduce steel costs by controlling fast quenching without soft‐spotting, cracking or dimensional distortion. It is odour‐free, non‐toxic, non‐sludging and contains a corrosion inhibitor. Gross contamination is the only cause for replacement with fresh fluid. It is applicable to both spray and immersion systems in precision induction hardening and furnace heat treating.