Temporary cement tectoplasty: a technique to improve prefabricated hip spacer stability in two-stage surgery for infected hip arthroplasty.

This technical note describes an intraoperatively custom-made, antibiotic-loaded bone cement roof, used in conjunction with a prefabricated hip spacer to improve component stability, as part of the first stage of a two-stage procedure for an infected hip implant. This technique was successfully used in seven cases who presented with extensive superior and/or posterio-superior acetabular defect, which created a risk of spacer dislocation. With this technique we were able to avoid any further dislocation in these seven cases. We believe that the technique may reduce postoperative spacer dislocation in cases with extensive acetabular defects, while improving clinical outcomes.

Clinical and radiological study of sternal fractures in pediatrics. / Estudio clínico radiológico de las fracturas esternales en edad pediátrica.

Sternal fractures are considered uncommon in pediatric patients. Classically, they have been described as fractures secondary to high-energy trauma that have a risk of associated lesions. OBJECTIVE: To describe the clinical and imaging features of sternal fractures in patients less than 18 years of age. MATERIAL AND METHODS: We retrospectively reviewed 79 pediatric patients diagnosed with sternal fractures after trauma. RESULTS: We found that 92.4% of the fractures were caused by low-energy trauma and that associated lesions were present in only 3 (4%) patients. CONCLUSION: Our results suggest that sternal fractures in children are often due to lesser trauma and that associated lesions are rare.

Reversal of cardiac cirrhosis following orthotopic heart transplantation.

Irreversible hepatic cirrhosis greatly increases the risks attending heart transplantation (HT), and is accordingly considered to be an absolute contraindication for HT unless combined heart and liver transplantation can be performed. It is now recognized that hepatic cirrhosis can undergo regression if the source of insult is removed, but no cases of post-HT regression of cirrhosis of cardiac origin have hitherto been reported. Here we report a case of cardiac cirrhosis that underwent complete regression following orthotopic HT, and we discuss the implications of this case.

The efficacy and safety of ezetimibe for treatment of dyslipidemia after heart transplantation.

INTRODUCTION: Statins, although the treatment of choice for dyslipidemia after heart transplantation (HT), are not always well tolerated or effective. In such cases, administration of ezetimibe may be useful. AIM: The aim of this study was to assess the efficacy and safety of ezetimibe, with or without statins, after HT. METHOD: Thirty-six HT patients, 97% of whom were males of overall mean age of 57 +/- 13 years, were all unable to reach target lipid levels with statins alone and/or were intolerant of statins. They were prescribed ezetimibe, with or without a statin. Efficacy and safety were evaluated after 1, 3, 6, and 12 months. RESULTS: Thirty-four patients were evaluated at 1 month and 12 months. Ezetimibe was prescribed to 27 patients (75%) because of statin inefficacy, and to 9 patients (25%) because of statin intolerance, manifested by myalgia in 4 cases (11%), hepatotoxicity in 2 cases (6%), and rhabdomyolysis in 3 cases (8%). Lipid levels (mg/dL; baseline vs 1 year) were as follows: cholesterol, 235 +/- 49 versus 167 +/- 32 (P = .013); LDL cholesterol, 137 +/- 47 versus 89 +/- 29 (P = .001); HDL cholesterol, 54 +/- 13 versus 51 +/- 10 (P = .235); and triglycerides, 243 +/- 187 versus 143 +/- 72 (P = .022). There were no cases of liver toxicity, renal dysfunction, or significant alteration of immunosuppressive pharmacokinetics. Ezetimibe was withdrawn from 2 patients because of hand edema or asymptomatic recurrence of rhabdomyolysis first caused by statins. CONCLUSIONS: With or without a statin, ezetimibe was generally well tolerated, reducing total cholesterol, LDL cholesterol, and triglyceride levels with no long-term alteration of HDL cholesterol levels. CPK surveillance is recommended because of a slight continued risk of adverse effects. Further studies should evaluate the benefit for survival.

Application of multivariable statistical techniques in plant-wide WWTP control strategies analysis.

The main objective of this paper is to present the application of selected multivariable statistical techniques in plant-wide wastewater treatment plant (WWTP) control strategies analysis. In this study, cluster analysis (CA), principal component analysis/factor analysis (PCA/FA) and discriminant analysis (DA) are applied to the evaluation matrix data set obtained by simulation of several control strategies applied to the plant-wide IWA Benchmark Simulation Model No 2 (BSM2). These techniques allow i) to determine natural groups or clusters of control strategies with a similar behaviour, ii) to find and interpret hidden, complex and casual relation features in the data set and iii) to identify important discriminant variables within the groups found by the cluster analysis. This study illustrates the usefulness of multivariable statistical techniques for both analysis and interpretation of the complex multicriteria data sets and allows an improved use of information for effective evaluation of control strategies.

Multicriteria evaluation tools to support the conceptual design of activated sludge systems.

During the past decade the pressure of the whole spectrum of stakeholders has increased considerably leading the consideration of different types of objectives, i.e. economical, technical, legal and environmental, into the process design efforts. Thus, the traditional design approaches should turn into more complex assessment methods including different types of objectives in order to conduct integrated assessments. The objective of this paper is to present and discuss the usefulness of three evaluation tools, based on multicriteria decision analysis, to support the conceptual design of activated sludge systems These support tools consist of: i) preliminary multiobjective optimization, where the most promising options (those located near to the optimum) are compared based on the results of dynamic simulation, ii) identification of strong and weak points for each option by means of classification trees and the subsequent extraction of knowledge-based rules, and iii) evaluation of the trade-offs between a certain evaluation criteria and the overall process performance through the integrated application of mathematical modelling and qualitative knowledge extracted during the design process.

"Reverse" hip spacer for massive distal femur defects in peri-prosthetic knee infections. / Espaciador de cadera «invertido¼ para defectos masivos de fémur distal en infecciones periprotésicas de rodilla.

BACKGROUND: Bone loss in the distal femur is a common problem in knee revision surgeries. The problem is exacerbated in the context of an active infection. In extreme cases this bone loss could compromise the feasibility of a two-stage exchange protocol using dynamic spacers due to the inherent instability of this type of spacers. Use of a hip prefabricated spacer in a "reverse" way forming a ball-and- socket joint is a therapeutic option in cases of massive bone defect and infection. MATERIAL AND METHODS: A retrospective review was performed of our institutional database to identify all cases of massive distal femoral defect in which this technique was used from January 2010 to December 2013. A record was made of the epidemiological data, characteristics of the infection (clinical and microbiological), and adverse event during the spacer stage. The main end-point was the infection eradication rate (minimum: 18 months of follow-up). The complications associated with the technique were also assessed. Finally, each patient completed a visual analogue pain scale, and a satisfaction questionnaire (SAPS). RESULTS: This technique was successfully used in six cases so far, controlling the infection in all cases. Mean femoral defect was 117cm (range: 32-191cm). Mean time with spacer was 7.6 months, with no major complications. All but one patient reached second stage reconstruction with a mega-prosthesis, and mean time since second stage was 34.7 months. All patients stated high levels of satisfaction with the technique employed, as well as and low pain scores (mean visual analogue pain scale: 1; range: 0-4). CONCLUSION: A reproducible and safe technique is described. Patients report a high level of satisfaction with the procedure, and there were no cases of recurrence of the infection after a minimum follow-up of 18 months.

Terrible triad of the elbow--role of the coronoid process: a case report.

Posterior dislocation of the elbow joint with fracture of both the radial head and coronoid process, the so-called 'terrible triad', is a complex and difficult-to-treat injury. We report a case of a 34-year-old man with terrible triad of the elbow and associated injuries secondary to a fall. The patient was treated with radial head osteosynthesis, resection of the coronoid process fragments, and stabilisation of the ulnohumeral joint by Kirschner wire transfixation. The sequence of treatment steps is provided. The priority for treating multiple injuries should be established. The integrity of the coronoid process is essential for providing the elbow with maximum functionality.

Single-breath, room-air method for measuring closing volume (phase 4) in the normal human lung.

The purpose of this study was to evaluate a new method to measure closing volume (CV). This new method does not require oxygen or inert gases to be inhaled to obtain the onset of phase 4. Because there are regional differences in the concentrations of the resident alveolar gases (O2, CO2, and N2), there should be an abrupt change in the concentration of these gases at the terminal portion of a prolonged expired vital capacity (VC) that marks the onset of phase 4. Nine normal healthy subjects, 30 to 65 years of age, inspired room air from residual volume (to mimic the maneuver of the standard single breath N2 (SBN2) washout test) to total lung capacity. During the expiration (flow constant at 250 ml.s-1) following a 10-s breath hold at total lung capacity, the exhaled gas was analyzed with a mass spectrometer for fractions of O2, CO2, and N2. Although the onset of phase 4 can be shown as the change in concentration of any of the three alveolar resident gases, oxygen was selected because (1) it demonstrates a greater apex to base concentration gradient than that found with CO2 and N2, and (2) a clear identification of the onset of phase 4 (minimum value of O2 fraction). With this method, the mean +/- SEM of CV was 16.8 +/- 1.52 percent (CV x 100/VC). No significant difference was found among the room air method, SBN2 method, and the helium bolus technique.

[2 cases of vertebral hydatidosis treated by the association of surgery and mebendazole]. / Deux cas d'hydatidose vertébrale traités par association chirurgie et mébendazol.

Two cases of vertebral hydatidosis were diagnosed only at the time of operation. The first one, a lumbar localisation treated as a tuberculosis, by posterior graft and chemotherapy went to a large vertebral destruction with paraplegia. An anterior approach revealed the hydatids. A large excision associated with graft and osteosynthesis gave only a temporary improvement, but the treatment by Mebendazol cured the neurological symptoms. The second case, with a large destruction of L5 and S1, was also treated as a tuberculosis even after a decompressive laminectomy and recognized at a second operation on the sacrum. A left paralysis, incompletely improved by a decompression, appeared as favourably influenced by Mebendazol. Epidemiologic conditions of hydatosis, difficulties of diagnosis of the rare bony localizations, are recalled. The great problem of treatment, especially in the most frequent vertebral lesions, where complete excision is impossible, appears as hopefully improved by Mebendazol.

Ventilation inhomogeneities and mixed venous blood N2 in multibreath N2 washout.

The single path model of airway gas transport, with and without a distributed blood source term, was used to simulate multiple-breath N2 washout by breathing pure O2 in two lung models: a single-region lung model (SRLM) which produces series inhomogeneity, and a seven-region lung model (7RLM) incorporating both series and parallel inhomogeneities. Normalized phase III slopes (Sn) from N2 expirograms were computed for each breath and compared with published human experimental data obtained under similar conditions. The 7RLM predicts well the trend of experimental Sn N2 changes and is superior to the SRLM in the first part (the unsteady state), implying that this part of the curve is mostly due to convective mixing of the seven parallel flow streams. In the quasi-steady state, the 7RLM is not obviously superior to the SRLM. Functional residual capacity and pulmonary perfusion are shown to strongly affect the number of breaths required to reach the quasi-steady state. The anatomical dimensions that appear to be critical in SRLM are not as important in the 7RLM.

Diffusion-convection equation solved in parallel regions of the lung.

The single path model of airway gas transport was incorporated into each of Cruz (Cruz, J. C. Respir. Physiol. 86:1-14, 1991). Thus, the effect of time on the predicted gas fractions in and out of the lung could be evaluated. Two experimental maneuvers were simulated: (1) fast inhalation of an argon-oxygen mixture from a functional residual capacity and fast exhalation to residual volume, including inspiratory breath holdings of 5-20 s, and (2) the standard single-breath nitrogen washout test. Expired argon and nitrogen are predicted within a +3% error of the experimental data with no breath holding. Breath holding predictions were at variance with experimental results because the solution of the diffusion-convection equation produced even mixing in the alveoli at the end of inspiration. The minimum square of the difference between the experimental data (standard single-breath nitrogen washout test) and those provided by the model was 0.0016. This model is capable of generating a nitrogen expirogram with four phases when a vital capacity of oxygen is inhaled. However, the model failed to produce a sharp distinction between phase 3 and phase 4. Thus, we conclude that uneven emptying of parallel regions generates any expirogram (a fast or slow expiratory maneuver). The alveolar gas stratification that is created during inspiration disappears at the end of the inspiratory maneuver. As a result, breath holding maneuvers cannot be predicted in the anatomical model used.

The Girdlestone pseudarthrosis in the treatment of infected hip replacements.

The results of 78 resections of the head and neck of the femur (Girdlestone pseudarthrosis) in patients with infected hip replacements were studied. The mean follow-up was 5 years. At the time of the resection, gram-positive organisms were found in 53% of the cases, gram-negative in 33%, and in 12% there were mixed flora. The Girdlestone pseudarthrosis controlled the infection in 86% and achieved satisfactory relief of pain in 83%. The mean shortening of the limb was 4.1 cm and every patient needed some type of external walking aid. We found no correlation between the type of organisms and the persistence of infection, nor between shortening and the functional results. The Girdlestone pseudarthrosis is an acceptable method of controlling infection and relieving pain after infection of a total hip replacement.

New method to calculate the N2 evolution from mixed venous blood during the N2 washout.

To model the normalized phase III slope (Sn) from N2 expirograms of the multibreath N2 washout is a challenge to researchers. Experimental measurements show that Sn increases with the number of breaths. Previously, we predicted Sn by setting the concentration (atm) of mixed venous blood (Fbi,N2) to a constant value of 0.3 after the fifth breath to calculate the amount of N2 transferred from the blood to the alveoli. As a consequence, the predicted curve of the Sn values showed a maximum before the quasi-steady state was reached. In this paper, we present a way of calculating the amount of N2 transferred from the blood to the alveoli by setting Fbi,N2 in the following way: In the first six breaths Fbi,N2 is kept constant at the initial value of 0.8 because circulation time needs at least 30 s to alter it. Thereafter, a single exponential function with respect the number of breaths is used: Fbi = 0.8 exp[0.112(6-n)], in which n is the breath number. The predicted Sn values were compared with experimental data from the literature. The assumption of an exponential decay in the N2 evolved from mixed venous blood is important in determining the shape of the Sn curve but new experimental data are needed to determine the validity of the model. We concluded that this new approach to calculate the N2 evolution from the blood is more meaningful physiologically.