84 resultados para Increasing failure rate

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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Resistance of trypanosomes to melarsoprol is ascribed to reduced uptake of the drug via the P2 nucleoside transporter. The aim of this study was to look for evidence of drug resistance in Trypanosoma brucei gambiense isolates from sleeping sickness patients in Ibba, South Sudan, an area of high melarsoprol failure rate. Eighteen T. b. gambiense stocks were phenotypically and only 10 strains genotypically characterized. In vitro, all isolates were sensitive to melarsoprol, melarsen oxide, and diminazene. Infected mice were cured with a 4 day treatment of 2.5mg/kg bwt melarsoprol, confirming that the isolates were sensitive. The gene that codes for the P2 transporter, TbATI, was amplified by PCR and sequenced. The sequences were almost identical to the TbAT1(sensitive) reference, except for one point mutation, C1384T resulting in the amino acid change proline-462 to serine. None of the described TbAT1(resistant)-type mutations were detected. In a T. b. gambiense sleeping sickness focus where melarsoprol had to be abandoned due to the high incidence of treatment failures, no evidence for drug resistant trypanosomes or for TbAT1(resistant)-type alleles of the P2 transporter could be found. These findings indicate that factors other than drug resistance contribute to melarsoprol treatment failures.

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INTRODUCTION Stable reconstruction of proximal femoral (PF) fractures is especially challenging due to the peculiarity of the injury patterns and the high load-bearing requirement. Since its introduction in 2007, the PF-locking compression plate (LCP) 4.5/5.0 has improved osteosynthesis for intertrochanteric and subtrochanteric fractures of the femur. This study reports our early results with this implant. METHODS Between January 2008 and June 2010, 19 of 52 patients (12 males, 7 females; mean age 59 years, range 19-96 years) presenting with fractures of the trochanteric region were treated at the authors' level 1 trauma centre with open reduction and internal fixation using PF-LCP. Postoperatively, partial weight bearing was allowed for all 19 patients. Follow-up included a thorough clinical and radiological evaluation at 1.5, 3, 6, 12, 24, 36 and 48 months. Failure analysis was based on conventional radiological and clinical assessment regarding the type of fracture, postoperative repositioning, secondary fracture dislocation in relation to the fracture constellation and postoperative clinical function (Merle d'Aubigné score). RESULTS In 18 patients surgery achieved adequate reduction and stable fixation without intra-operative complications. In one patient an ad latus displacement was observed on postoperative X-rays. At the third month follow-up four patients presented with secondary varus collapse and at the sixth month follow-up two patients had 'cut-outs' of the proximal fragment, with one patient having implant failure due to a broken proximal screw. Revision surgeries were performed in eight patients, one patient receiving a change of one screw, three patients undergoing reosteosynthesis with implantation of a condylar plate and one patient undergoing hardware removal with secondary implantation of a total hip prosthesis. Eight patients suffered from persistent trochanteric pain and three patients underwent hardware removal. CONCLUSIONS Early results for PF-LCP osteosynthesis show major complications in 7 of 19 patients requiring reosteosynthesis or prosthesis implantation due to secondary loss of reduction or hardware removal. Further studies are required to evaluate the limitations of this device.

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BACKGROUND We observed a case of conductor externalization in a Biotronik Linox lead. OBJECTIVE To investigate lead performance of the Linox and identical Sorin Vigila lead and prevalence of conductor externalization. METHODS We compared lead performance of all Linox and Vigila leads implanted at our center (BL group; n=93) with all Boston Scientific Endotak Reliance leads (ER group; n=190) and Medtronic Sprint Quattro leads (SQ group; n=202) implanted during the same period. We screened all BL group patients for conductor externalization. RESULTS We identified 8 cases of lead failures in the BL group (index case of conductor externalization; 6 cases of non-physiological high rate sensing; one case of high voltage conductor fracture). Prospective, fluoroscopic screening of 98% of all active BL group cases revealed one additional case of conductor externalization. Median follow-up was 41, 27 and 29 months for the BL group, ER group and SQ group, respectively, lead survival 94.9%, 99.2% and 100% at 3 years, and 88%, 97.5% and 100% at 5 years (p=0.038 for BL group vs. ER group, and p=0.007 for BL group vs. SQ group by the log-rank test). Younger age at implant was an independent predictor for lead failure in the BL group (adjusted HR 0.85 [95% confidence interval 0.77-0.94]; p=0.001). CONCLUSION At our center, survival of the Linox lead is 88% at five years and significantly worse than its comparators. Conductor externalization is present in a minority of failed Linox leads. Younger age at implant is an independent predictor of Linox lead failure.

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Determination of chloride concentration in sweat is the current diagnostic gold standard for Cystic Fibrosis (CF). Nanoduct(R) is a new analyzing system measuring conductivity which requires only 3 microliters of sweat and gives results within 30 minutes. The aim of the study was to evaluate the applicability of this system in a clinical setting of three children's hospitals and borderline results were compared with sweat chloride concentration. Over 3 years, 1,041 subjects were tested and in 946 diagnostic results were obtained. In 95 children, Nanoduct(R) failed (9.1% failure rate), mainly due to failures in preterm babies and newborns. Assuming 59 mmol/L as an upper limit of normal conductivity, all our 46 CF patients were correctly diagnosed (sensitivity 100%, 95% CI: 93.1-100; negative predicted value 100% (95% CI: 99.6-100) and only 39 non CF's were false positive (39/900, 4.3%; specificity 95.7%, 95%CI: 94.2-96.9, positive predicted value 54.1% with a 95%CI: 43.4-65.0). Increasing the diagnostic limit to 80 mmol/L, the rate fell to 0.3% (3/900). CF patients had a median conductivity of 115 mmol/L; the non-CF a median of 37 mmol/L. In conclusion, the Nanoduct(R) test is a reliable diagnostic tool for CF diagnosis: It has a failure rate comparable to other sweat tests and can be used as a simple bedside test for fast and reliable exclusion, diagnosis or suspicion of CF. In cases with borderline conductivity (60-80 mmol/L) other additional methods (determination of chloride and genotyping) are indicated.

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AIM: The purpose of this study was to systematically review the literature on the survival rates of palatal implants, Onplants((R)), miniplates and mini screws. MATERIAL AND METHODS: An electronic MEDLINE search supplemented by manual searching was conducted to identify randomized clinical trials, prospective and retrospective cohort studies on palatal implants, Onplants((R)), miniplates and miniscrews with a mean follow-up time of at least 12 weeks and of at least 10 units per modality having been examined clinically at a follow-up visit. Assessment of studies and data abstraction was performed independently by two reviewers. Reported failures of used devices were analyzed using random-effects Poisson regression models to obtain summary estimates and 95% confidence intervals (CI) of failure and survival proportions. RESULTS: The search up to January 2009 provided 390 titles and 71 abstracts with full-text analysis of 34 articles, yielding 27 studies that met the inclusion criteria. In meta-analysis, the failure rate for Onplants((R)) was 17.2% (95% CI: 5.9-35.8%), 10.5% for palatal implants (95% CI: 6.1-18.1%), 16.4% for miniscrews (95% CI: 13.4-20.1%) and 7.3% for miniplates (95% CI: 5.4-9.9%). Miniplates and palatal implants, representing torque-resisting temporary anchorage devices (TADs), when grouped together, showed a 1.92-fold (95% CI: 1.06-2.78) lower clinical failure rate than miniscrews. CONCLUSION: Based on the available evidence in the literature, palatal implants and miniplates showed comparable survival rates of >or=90% over a period of at least 12 weeks, and yielded superior survival than miniscrews. Palatal implants and miniplates for temporary anchorage provide reliable absolute orthodontic anchorage. If the intended orthodontic treatment would require multiple miniscrew placement to provide adequate anchorage, the reliability of such systems is questionable. For patients who are undergoing extensive orthodontic treatment, force vectors may need to be varied or the roots of the teeth to be moved may need to slide past the anchors. In this context, palatal implants or miniplates should be the TADs of choice.

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PURPOSE Clinical studies related to the long-term outcomes with implant-supported reconstructions are still sparse. The aim of this 10-year retrospective study was to assess the rate of mechanical/technical complications and failures with implant supported fixed dental prostheses (FDPs) and single crowns (SCs) in a large cohort of partially edentulous patients. MATERIALS AND METHODS The comprehensive multidisciplinary examination consisted of a medical/dental history, clinical examination, and a radiographic analysis. Prosthodontic examination evaluated the implant-supported reconstructions for mechanical/technical complications and failures, occlusal analysis, presence/absence of attrition, and location, extension, and retention type. RESULTS Out of three hundred ninety seven fixed reconstructions in three hundred three patients, two hundred sixty eight were SCs and one hundred twenty seven were FDPs. Of these three hundred ninety seven implant-supported reconstructions, 18 had failed, yielding a failure rate of 4.5% and a survival rate of 95.5% after a mean observation period of 10.75 years (range: 8.4-13.5 years). The most frequent complication was ceramic chipping (20.31%) followed by occlusal screw loosening (2.57%) and loss of retention (2.06%). No occlusal screw fracture, one abutment loosening, and two abutment fractures were noted. This resulted in a total mechanical/technical complication rate of 24.7%. The prosthetic success rate over a mean follow-up time of 10.75 years was 70.8%. Generalized attrition and FDPs were associated with statistically significantly higher rates of ceramic fractures when compared with SCs. Cantilever extensions, screw retention, anterior versus posterior, and gender did not influence the chipping rate. CONCLUSIONS After a mean exposure time of 10.75 years, high survival rates for reconstructions supported by Sand-blasted Large-grit Acid-etched implants can be expected. Ceramic chipping was the most frequent complication and was increased in dentitions with attrition and in FDPs compared with SCs.

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AIM To assess the long-term success of maxillary fixed retainers, investigate their effect on gingival health, and analyse the survival rate after a mean period of 7 years (minimum 5 years) in retention. SUBJECTS AND METHODS Forty one subjects were included in the study A clinical examination of the upper canine to canine region including gingival index (GI), plaque index, probing depth, and bleeding on probing (BOP) was performed. Intraoral photographs and dental impressions were taken and irregularity index was determined and compared to the values of the immediate post-therapeutic values; failures of retainers were also recorded and analysed. RESULTS The mean observed retention time was 7 years and 5 months. Irregularity index: Changes occurring during retention were statistically different between the lateral incisors bonded to retainers and the canines not bonded to retainers. Only six patients showed changes in irregularity index of the lateral incisors in spite of a retainer in place. Periodontal health: The median value of the GI for all teeth bonded to upper retainers was 1.10 and the median value of the plaque index (PI) was 1.14. PI was not a significant predictor of GI. The overall BOP of the bonded teeth to the retainer for each participant was 22.3 per cent. Failure rate: Twenty-eight out of 41 patients experienced no failure of the upper bonded retainer (68.3 per cent). Detachments were the most frequent incidents. CONCLUSION Although plaque accumulation might be increased in patients with already poor oral hygiene, maxillary bonded retainers caused no significant negative effects on the periodontal health.

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OBJECTIVES: The aim of this study was to compare the long-term outcomes of implants placed in patients treated for periodontitis periodontally compromised patients (PCP) and in periodontally healthy patients (PHP) in relation to adhesion to supportive periodontal therapy (SPT). MATERIAL AND METHODS: One hundred and twelve partially edentulous patients were consecutively enrolled in private specialist practice and divided into three groups according to their initial periodontal condition: PHP, moderate PCP and severe PCP. Perio and implant treatment was carried out as needed. Solid screws (S), hollow screws (HS) and hollow cylinders (HC) were installed to support fixed prostheses, after successful completion of initial periodontal therapy (full-mouth plaque score <25% and full-mouth bleeding score <25%). At the end of treatment, patients were asked to follow an individualized SPT program. At 10 years, clinical measures and radiographic bone changes were recorded by two calibrated operators, blinded to the initial patient classification. RESULTS: Eleven patients were lost to follow-up. During the period of observation, 18 implants were removed because of biological complications. The implant survival rate was 96.6%, 92.8% and 90% for all implants and 98%, 94.2% and 90% for S-implants only, respectively, for PHP, moderate PCP and severe PCP. The mean bone loss was 0.75 (+/- 0.88) mm in PHP, 1.14 (+/- 1.11) mm in moderate PCP and 0.98 (+/- 1.22) mm in severe PCP, without any statistically significant difference. The percentage of sites, with bone loss > or =3 mm, was, respectively, 4.7% for PHP, 11.2% for moderate PCP and 15.1% for severe PCP, with a statistically significant difference between PHP and severe PCP (P<0.05). Lack of adhesion to SPT was correlated with a higher incidence of bone loss and implant loss. CONCLUSION: Patients with a history of periodontitis presented a lower survival rate and a statistically significantly higher number of sites with peri-implant bone loss. Furthermore, PCP, who did not completely adhere to the SPT, were found to present a higher implant failure rate. This underlines the value of the SPT in enhancing the long-term outcomes of implant therapy, particularly in subjects affected by periodontitis, in order to control reinfection and limit biological complications.

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Balloon sinuplasty is a tool that is used to treat selected patients with paranasal sinus pathologies. No studies have investigated the aetiology of failed access to the frontal sinus. The aim of our study was to specify the intraoperative technical failure rate and to analyse the aetiology of the failed access to predict potential technical difficulties before surgery. We retrospectively analysed the charts of patients who underwent balloon sinuplasty from November 2007 to July 2010 at three different ENT-Centres. CT-analysis of the patients with failed access was performed. Of the 104 frontal sinuses, dilation of 12 (12%) sinuses failed. The anatomy of all failed cases revealed variations in the frontal recess (frontoethmoidal-cell, frontal-bulla-cell or agger-nasi-cell) or osteoneogenesis. In one patient, a lymphoma was overlooked during a balloon only procedure. The lymphoma was diagnosed 6 months later with a biopsy during functional endoscopic sinus surgery. In complex anatomical situations of the frontal recess, balloon sinuplasty may be challenging or impossible. In these situations, it is essential to have knowledge of classical functional endoscopic sinus surgery of the frontal recess area. The drawbacks of not including a histopathologic exam should be considered in balloon only procedures.

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Microvascular surgery has become an important method for reconstructing surgical defects due to trauma, tumors or after burn. The most important factor for successful free flap transfer is a well-executed anastomosis. The time needed to perform the anastomosis and the failure rate are not negligible despite the high level of operator's experience. During the history, many alternatives were tried to help the microsurgeon and to reduce the complications. A Medline literature search was performed to find articles dealing with non-suture methods of microvascular anastomosis. Many historical books were also included. The non-suture techniques can be divided into four groups based on the used mechanism of sutures: double intubation including tubes and stents, intubation-eversion including simple rings, double eversion including staples and double rings, and wall adjustement with adhesives or laser. All these techniques were able to produce a faster and easier microvascular anastomosis. Nevertheless, disadvantages of the suturless techniques include toxicity, high cost, leakage or aneurysm formation. More refinement is needed before their widespread adoption. Thus, laser-assisted microvascular anastomosis using 1,9 μm diode laser appeared to be a safe and reliable help for the microsurgeon and may be further developed in the near future.

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PURPOSE: Neoadjuvant treatment is an accepted standard approach for treating locally advanced esophago-gastric adenocarcinomas. Despite a response of the primary tumor, a significant percentage dies from tumor recurrence. The aim of this retrospective exploratory study from two academic centers was to identify predictors of survival and recurrence in histopathologically responding patients. METHODS: Two hundred thirty one patients with adenocarcinomas (esophagus: n = 185, stomach: n = 46, cT3/4, cN0/+, cM0) treated with preoperative chemotherapy (n = 212) or chemoradiotherapy (n = 19) followed by resection achieved a histopathological response (regression 1a: no residual tumor (n = 58), and regression 1b < 10 % residual tumor (n = 173)). RESULTS: The estimated median overall survival was 92.4 months (5-year survival, 56.6 %) for all patients. For patients with regression 1a, median survival is not reached (5-year survival, 71.6 %) compared to patients with regression 1b with 75.3 months median (5-year survival, 52.2 %) (p = 0.031). Patients with a regression 1a had lymph node metastases in 19.0 versus 33.7 % in regression 1b. The ypT-category (p < 0.001), the M-category (p = 0.005), and the type of treatment (p = 0.04) were found to be independent prognostic factors in R0-resected patients. The recurrence rate was 31.7 % (n = 66) (local, 39.4 %; peritoneal carcinomatosis, 25.7 %; distant metastases, 50 %). Recurrence was predicted by female gender (p = 0.013), ypT-category (p = 0.007), and M-category (p = 0.003) in multivariate analysis. CONCLUSION: Response of the primary tumor does not guarantee recurrence-free long-term survival, but histopathological complete responders have better prognosis compared to partial responders. Established prognostic factors strongly influence the outcome, which could, in the future, be used for stratification of adjuvant treatment approaches. Increasing the rate of histopathological complete responders is a valid endpoint for future clinical trials investigating new drugs.

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Lesions of the rotator cuff (RC) are among the most frequent tendon injuries. In spite of the developments in both open and arthroscopic surgery, RC repair still very often fails. In order to reduce the failure rate after surgery, several experimental in vitro and in vivo therapy methods have been developed for biological improvement of the reinsertion. This article provides an overview of the current evidence for augmentation of RC reconstruction with growth factors. Furthermore, potential future therapeutic approaches are discussed. We performed a comprehensive search of the PubMed database using various combinations of the keywords "tendon," "rotator cuff," "augmentation," "growth factor," "platelet-rich fibrin," and "platelet-rich plasma" for publications up to 2011. Given the linguistic capabilities of the research team, we considered publications in English, German, French, and Spanish. We excluded literature reviews, case reports, and letters to the editor.

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Coronary artery disease (CAD) and atrial fibrillation (AF) are major determinants of morbidity and mortality. A combined treatment with antiplatelet agents and vitamin K antagonists limits the risk of stent thrombosis and stroke while increasing the rate of bleeding. The objective of this study was to investigate the impact of atrial fibrillation (AF) on long-term clinical outcomes in patients with CAD undergoing percutaneous coronary intervention (PCI) with drug-eluting stents (DES).

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Glucocorticosteroid-induced spinal osteoporosis (GIOP) is the most frequent of all secondary types of osteoporosis. The understanding of the pathophysiology of glucocorticoid (GC) induced bone loss is of crucial importance for appropriate treatment and prevention of debilitating fractures that occur predominantly in the spine. GIOP results from depressed bone formation due to lower activity and higher death rate of osteoblasts on the one hand, and from increase bone resorption due to prolonged lifespan of osteoclasts on the other. In addition, calcium/phosphate metabolism may be disturbed through GC effects on gut, kidney, parathyroid glands and gonads. Therefore, therapeutic agents aim at restoring balanced bone cell activity by directly decreasing apoptosis rate of osteoblasts (e.g., cyclical parathyroid hormone) or by increasing apoptosis rate of osteoclasts (e.g., bisphosphonates). Other therapeutical efforts aim at maintaining/restoring calcium/phosphate homeostasis: improving intestinal calcium absorption (using calcium supplementation, vitamin D and derivates) and avoiding increased urinary calcium loss (using thiazides) prevent or counteract a secondary hyperparthyroidism. Bisphosphonates, particularly the aminobisphosphonates risedronate and alendronate, have been shown to protect patients on GCs from (further) bone loss to reduce vertebral fracture risk. Calcitonin may be of interest in situation where bisphosphonates are contraindicated or not applicable and in cases where acute pain due to vertebral fracture has to be manage. The intermittent administration of 1-34-parathormone may be an appealing treatment alternative, based on its documented anabolic effects on bone resulting from the reduction of osteoblastic apoptosis. Calcium and vitamin D should be a systematic adjunctive measure to any drug treatment for GIOP. Based on currently available evidence, fluoride, androgens, estrogens (opposed or unopposed) cannot be recommended for the prevention and treatment of GIOP. However, substitution of gonadal hormones may be indicated if GC-induced hypogonadism is present and leads to clinical symptoms. Data using the SERM raloxifene to treat or prevent GIOP are lacking, as are data using the promising bone anabolic agent strontium ranelate. Kyphoplasty performed in appropriately selected osteoporotic patients with painful vertebral fractures is a promising addition to current medical treatment.

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Total hip arthroplasty (THA) still carries a higher failure rate in patients with avascular necrosis of the femoral head (AVN) than in a similar patient population with THA for other reasons. This is particularly true for the acetabular component. One of the major factors accounting for this is the compromised acetabular bone quality with structural defects subsequent to collapsing of the femoral head in high-grade AVN. In this study we implanted an acetabular reinforcement ring with hook (ARRH), which had been used successfully for other indications with acetabular bone stock deficiency, in 32 consecutive THA's in 29 patients with AVN. Five patients died during the observation period of causes unrelated to the surgery, one patient was lost to follow-up and one patient could not be followed up due to chronic illness, leaving 25 hips (23 patients) with a minimum follow-up of ten years (mean: 11.8; range: 10-15). The mean Merle d'Aubigne score increased significantly from 7.7 preoperatively to 16.6 postoperatively (p < 0.001). One revision was performed for aseptic stem loosening. Of the unrevised hips, one acetabular component was classified as definitively loose. The cumulative 12-year survivorship for THA with ARRH in AVN was 95.2% (confidence interval: 86.1-100%) for both components, 100% for the cup and 95.2% for the stem (86.1-100%).