Towards an accurate biomechanical model of the ankle

When compared with similar joint arthroplasties, the prognosis of Total Ankle Replacement (TAR) is not satisfactory although it shows promising results post surgery. To date, most models do not provide the full anatomical functionality and biomechanical range of motion of the healthy ankle joint. This has sparked additional research and evaluation of clinical outcomes in order to enhance ankle prosthesis design. However, the limited biomechanical data that exist in literature are based upon two-dimensional, discrete and outdated techniques1 and may be inaccurate. Since accurate force estimations are crucial to prosthesis design, a paper based on a new biomechanical modeling approach, providing three dimensional forces acting on the ankle joint and the surrounding tissues was published recently, but the identified forces were suspected of being under-estimated, while muscles were . The present paper reports an attempt to improve the accuracy of the analysis by means of novel methods for kinematic processing of gait data, provided in release 4.1 of the AnyBody Modeling System (AnyBody Technology, Aalborg, Denmark) Results from the new method are shown and remaining issues are discussed.

Política Nacional de Saúde Bucal: uma análise da reorganização da atenção à saúde bucal em Cascavel e demais municípios integrantes da 10 Regional de Saúde no Estado do Paraná

O Ministério da Saúde (MS), através de sua política de incentivos financeiros, vem promovendo um processo de reorganização da atenção à saúde bucal, com a implantação das Equipes de Saúde Bucal (ESB) na Estratégia Saúde da Família (ESF), no âmbito da atenção básica, e dos Centros de Especialização Odontológica (CEO) e Laboratório Regional de Próteses Dentárias (LRPD), na atenção secundária. Nesse contexto, esta dissertação foca o processo de reorganização da atenção à saúde bucal em Cascavel e nos demais municípios pertencentes à 10 Regional de Saúde do Estado do Paraná. Consideramos que, em tese, este processo de regionalização deve ser orientado pelas diretrizes da Política Nacional de Saúde Bucal (PNSB), que priorizam a atenção básica em saúde bucal através da ESF e trazem ainda como proposta a ampliação da média e alta complexidade em saúde bucal. Foi realizada ampla pesquisa nas bases de dados do DATASUS, relativos à produção das ações de saúde bucal dos 25 municípios pertencentes à 10 Regional de Saúde do Estado do Paraná, no período de janeiro de 1998 a dezembro de 2007. Os dados foram cotejados com aqueles disponibilizados pelo Departamento de Atenção Básica (DAB) relativos à implantação das ESB, CEO e LRPD. Os resultados demonstram que, no âmbito da 10 RS, ocorreu ampliação do acesso e da oferta de ações e serviços de saúde bucal. No entanto, a despeito da ampliação do acesso, há um longo caminho a ser percorrido para que haja avanços significativos nas condições de saúde bucal da população, tal como é a proposta da PNSB.

Formação in vitro de biofilme de Candida albicans em materiais usados no preenchimento dos acessos aos parafusos das próteses sobre implantes

Os orifícios de acesso aos parafusos de retenção devem ser preenchidos para que o parafuso não seja danificado caso seja necessária a remoção da prótese. Dentre os materiais mais utilizados estão o algodão, a fita de politetrafluoretileno e a guta percha. O objetivo deste estudo é avaliar a formação de biofilme de Candida albicans nos materiais anteriormente descritos, buscando estabelecer um parâmetro que contribua para a escolha do tipo de material mais adequado a ser utilizado clinicamente. Foram utilizados UCLAs, análogos e parafusos sextavados, todos de titânio. Os conjuntos foram montados com torque de 32N. Os materiais foram condensados no interior dos UCLAs e colocados em meio de cultura com uma suspensão de 3x106 células/ml de Candida albicans. O sistema foi armazenado à 37C com agitação, por 15 dias e o meio foi renovado a cada 48 horas. A quantificação de biofilme foi realizada pelo ensaio de MTT e leitura à 490nm, resultando em diferentes valores de densidade óptica. A normalidade (p=0,304 - Kolmogorov-Smirnov) e a igualdade de variâncias (p=0,721 - Scheffe) foram testadas primeiramente. O teste de análise de variância demonstrou diferença significativa entre os grupos (p<0,001) e com o Holm-Sidak foi observada diferença significativa entre os grupos algodão e guta (p<0,05) e algodão e fita de politetrafluoetileno (p<0,05); não houve diferença significativa entre os grupos guta e fita de politatrafluoretileno (p>0,05), apesar dos valores da fita de politetrafluoetileno terem sido maiores. Considerando-se as limitações deste estudo in vitro, podemos concluir que tanto a guta-percha quanto a fita de politetrafluoretileno apresentaram menor formação de biofilme, não havendo diferença estatisticamente significativa entre os materiais. O algodão apresentou um nível de formação de biofilme significativamente maior que a fita de politetrafluoretileno e a guta percha. Diante disso, serão necessários novos estudos para confirmar as limitações que este tipo de material pode apresentar quando usado como material de preenchimento do acesso do parafuso da prótese sobre implante.

Uso de equipamento auxiliar no preparo dentário para próteses

Trabalho apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária.

Síndrome de Kelly

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária

Stream segregation on a single electrode as a function of pulse rate in cochlear implant listeners.

While cochlear implants (CIs) usually provide high levels of speech recognition in quiet, speech recognition in noise remains challenging. To overcome these difficulties, it is important to understand how implanted listeners separate a target signal from interferers. Stream segregation has been studied extensively in both normal and electric hearing, as a function of place of stimulation. However, the effects of pulse rate, independent of place, on the perceptual grouping of sequential sounds in electric hearing have not yet been investigated. A rhythm detection task was used to measure stream segregation. The results of this study suggest that while CI listeners can segregate streams based on differences in pulse rate alone, the amount of stream segregation observed decreases as the base pulse rate increases. Further investigation of the perceptual dimensions encoded by the pulse rate and the effect of sequential presentation of different stimulation rates on perception could be beneficial for the future development of speech processing strategies for CIs.

Outcomes of metallic stents for malignant ureteral obstruction.

PURPOSE: Malignant ureteral obstruction often necessitates chronic urinary diversion and is associated with high rates of failure with traditional ureteral stents. We evaluated the outcomes of a metallic stent placed for malignant ureteral obstruction and determined the impact of risk factors previously associated with increased failure rates of traditional stents. MATERIALS AND METHODS: Patients undergoing placement of the metallic Resonance® stent for malignant ureteral obstruction at an academic referral center were identified retrospectively. Stent failure was defined as unplanned stent exchange or nephrostomy tube placement for signs or symptoms of recurrent ureteral obstruction (recurrent hydroureteronephrosis or increasing creatinine). Predictors of time to stent failure were assessed using Cox regression. RESULTS: A total of 37 stents were placed in 25 patients with malignant ureteral obstruction. Of these stents 12 (35%) were identified to fail. Progressive hydroureteronephrosis and increasing creatinine were the most common signs of stent failure. Three failed stents had migrated distally and no stents required removal for recurrent infection. Patients with evidence of prostate cancer invading the bladder at stent placement were found to have a significantly increased risk of failure (HR 6.50, 95% CI 1.45-29.20, p = 0.015). Notably symptomatic subcapsular hematomas were identified in 3 patients after metallic stent placement. CONCLUSIONS: Failure rates with a metallic stent are similar to those historically observed with traditional polyurethane based stents in malignant ureteral obstruction. The invasion of prostate cancer in the bladder significantly increases the risk of failure. Patients should be counseled and observed for subcapsular hematoma formation with this device.

Predicting revision risk for aseptic loosening of femoral components in total flip arthroplasty in individual patients - A finite element study

Advances in surgical procedure, prosthesis design, and biomaterials performance have considerably increased the longevity of total joint replacements. Preoperative planning is another step in joint replacement that may have the potential to improve clinical outcome for the individual patient, but has remained relatively consistent for a longtime. One means of advancing this aspect of joint replacement surgery may be to include predictive computer simulation into the planning process. In this article, the potential of patient-specific finite element analysis in preoperative assessment is investigated. Seventeen patient-specific finite element models of cemented Charnley reconstructions were created, of which six were early (

Prosthodontic care for elderly patients

For older patients, clinicians should consider maintaining teeth and using functionally-orientated treatment strategies as an alternative to removable prostheses. When the remaining dentition has a poor prognosis, key teeth should be preserved as overdenture abutments and a gradual transition to edentulousness planned. Where complete dentures are provided, these can be retained using dental implants to overcome many of the problems associated with conventional replacement dentures.

CLINICAL RELEVANCE: The elderly population of today is better informed and more demanding of oral healthcare providers than previous generations. Clinicians should be aware of all the prosthodontic treatment options available for older patients.

Caries and the older patient

Ageing of the population, together with prolonged retention of teeth, has brought new challenges to dentistry. Whereas in the past oral care for the elderly was restricted to provision of dentures, older patients are now presenting with dental caries and failed restorations. These problems may have an impact on their general health and quality of life. Poor oral hygiene, xerostomia and diet are among the risk factors for caries in older patients and need to be addressed in order to achieve control of the disease. Carious lesions can be treated conservatively in many cases or may need surgical management.

CLINICAL RELEVANCE: Caries is an oral health issue among older patients and can result in tooth loss. Oral health has a great impact on general health and quality of life of elderly people.

The Impact of Multifocal Intraocular Lens in Retinal Imaging with Optical Coherence Tomography

Multifocal intraocular lenses (MF IOLs) have concentric optical zones with different dioptric power, enabling patients to have good visual acuity at multiple focal points. However, several optical limitations have been attributed to this particular design. The purpose of this study is to access the effect of MF IOLs design on the accuracy of retinal optical coherence tomography (OCT). Cross-sectional study conducted at the Refractive Surgery Department of Central Lisbon Hospital Center. Twenty-three eyes of 15 patients with a diffractive MF IOL and 27 eyes of 15 patients with an aspheric monofocal IOL were included in this study. All patients underwent OCT macular scans using Heidelberg Spectralis®. Macular thickness and volume values and image quality (Q factor) were compared between the two groups. There were no statistically significant differences between both groups regarding macular thickness or volume measurements. Retinal OCT image quality was significantly lower in the MF IOL group (p < 0.01). MF IOLs are associated with a significant decrease in OCT image quality. However, this fact does not seem to compromise the accuracy of spectral domain OCT retinal measurements.

Percutaneous Treatment of Mitral Valve Regurgitation: Initial Experience with the MitraClip Device

INTRODUCTION: Mitral regurgitation (MR) is the most common valvular disease and has recently become the target of a number of percutaneous approaches. The MitraClip is virtually the only device for which there is considerable experience, with more than 20,000 procedures performed worldwide. OBJECTIVE: To describe our initial experience of the percutaneous treatment of MR with the MitraClip device. METHODS: We describe the first six MitraClip cases performed in this institution (mean age 58.5 ± 13.1 years), with functional MR grade 4+ and New York Heart Association (NYHA) heart failure class III or IV (n=3), with a mean follow-up of 290 ± 145 days. RESULTS: Procedural success (MR ≤ 2+) was 100%. Total procedure time was 115.8 ± 23.7 min, with no in-hospital adverse events and discharge between the fourth and eighth day, and consistent improvement in the six-minute walk test (329.8 ± 98.42 vs. 385.33 ± 106.95 m) and in NYHA class (three patients improved by two NYHA classes). During follow-up there were two deaths, in two of the four patients who had been initially considered for heart transplantation. CONCLUSION: In patients with functional MR the MitraClip procedure is safe, with both a high implantation and immediate in-hospital success rate. A longer follow-up suggests that the clinical benefit decreases or disappears completely in patients with more advanced heart disease, namely those denied transplantation or on the heart transplant waiting list.

PulseCath iVAC 3LTM hemodynamic performance for simple assisted flow.

The PulseCath iVAC 3L? left ventricular assist device is an option to treat transitory left heart failure or dysfunction post-cardiac surgery. Assisted blood flow should reach up to 3 l/min. In the present in vitro model exact pump flow, depending on various frequencies and afterload was examined. Optimal flow was achieved with inflation/deflation frequencies of about 70-80/min. The maximal flow rate was achieved at about 2.5 l/min with a minimal afterload of 22 mmHg. Handling of the device was easy due to the connection to a standard intra-aortic balloon pump console. With increasing afterload (up to a simulated mean systemic pressure of 66 mmHg) flow rate and cardiac support are in some extent limited.

Primary isolated aortic valve surgery in octogenarians.

We reviewed our surgery registry, to identify predictive risk factors for operative results, and to analyse the long-term survival outcome in octogenarians operated for primary isolated aortic valve replacement (AVR). A total of 124 consecutive octogenarians underwent open AVR from January 1990 to December 2005. Combined procedures and redo surgery were excluded. Selected variables were studied as risk factors for hospital mortality and early neurological events. A follow-up (FU; mean FU time: 77 months) was obtained (90% complete), and Kaplan-Meier plots were used to determine survival rates. The mean age was 82+/-2.2 (range: 80-90 years; 63% females). Of the group, four patients (3%) required urgent procedures, 10 (8%) had a previous myocardial infarction, six (5%) had a previous coronary angioplasty and stenting, 13 patients (10%) suffered from angina and 59 (48%) were in the New York Heart Association (NYHA) class III-IV. We identified 114 (92%) degenerative stenosis, six (5%) post-rheumatic stenosis and four (3%) active endocarditis. The predicted mortality calculated by logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) was 12.6+/-5.7%, and the observed hospital mortality was 5.6%. Causes of death included severe cardiac failure (four patients), multi-organ failure (two) and sepsis (one). Complications were transitory neurological events in three patients (2%), short-term haemodialysis in three (2%), atrial fibrillation in 60 (48%) and six patients were re-operated for bleeding. Atrio-ventricular block, myocardial infarction or permanent stroke was not detected. The age at surgery and the postoperative renal failure were predictors for hospital mortality (p value <0.05), whereas we did not find predictors for neurological events. The mean FU time was 77 months (6.5 years) and the mean age of surviving patients was 87+/-4 years (81-95 years). The actuarial survival estimates at 5 and 10 years were 88% and 50%, respectively. Our experience shows good short-term results after primary isolated standard AVR in patients more than 80 years of age. The FU suggests that aortic valve surgery in octogenarians guarantees satisfactory long-term survival rates and a good quality of life, free from cardiac re-operations. In the era of catheter-based aortic valve implantation, open-heart surgery for AVR remains the standard of care for healthy octogenarians.

In vivo testing of a novel adjustable glaucoma drainage device.

PURPOSE: We report on the in vivo testing of a novel noninvasively adjustable glaucoma drainage device (AGDD), which features an adjustable outflow resistance, and assess the safety and efficiency of this implant. METHODS: Under general anesthesia, the AGDD was implanted on seven white New Zealand rabbits for a duration of 4 months under a scleral flap in a way analogous to the Ex-PRESS device and set in an operationally closed position. The IOP was measured on a regular basis on the operated and control eyes using a rebound tonometer. Once a month the AGDD was adjusted noninvasively from its fully closed to its fully open position and the resulting pressure drop was measured. The contralateral eye was not operated and served as control. After euthanization, the eyes were collected for histology evaluation. RESULTS: The mean preoperative IOP was 11.1 ± 2.4 mm Hg. The IOP was significantly lower for the operated eye (6.8 ± 2 mm Hg) compared to the nonoperated eye (13.1 ± 1.6 mm Hg) during the first 8 days after surgery. When opening the AGDD from its fully closed to fully open position, the IOP dropped significantly from 11.2 ± 2.9 to 4.8 ± 0.9 mm Hg (P < 0.05). CONCLUSIONS: Implanting the AGDD is a safe and uncomplicated surgical procedure. The fluidic resistance was noninvasively adjustable during the postoperative period with the AGDD between its fully closed and fully open positions.