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Introduction Recurrent dislocations are still the most frequent reason for revision in total hip arthroplasty (THA). The impact of bearing surfaces on dislocations is still controversial. We hypothesized that: (1) bearing surfaces influence the revisions due to dislocations; (2) ceramic-on-ceramic reduced the revisions for dislocations in adjusted models; (3) Delta-on-Delta bearings reduced the revisions for dislocations in comparison to surfaces with cross-linked polyethylene. Materials and methods The regional arthroplasty registry was enquired about bearing surfaces and revisions for dislocations and instability. Unadjusted and adjusted rates were provided, including sex, age (28 mm; Results The rate of revisions for dislocations was significantly lower in ceramic-on-ceramic and metal-on-metal bearings (unadjusted rates). After adjusting for age, sex, and head size (36 and 28 mm), hard-on-hard bearings were protective (p p = 0.0009). The rate of revisions for dislocation was similar in bearings with cross-linked polyethylene and Delta-on-Delta articulations, in unadjusted and adjusted models. Conclusion Bearings with conventional polyethylene were more predisposed to dislocations. Currently adopted bearings exerted no significant influence on revisions due to dislocations. These findings could be primarily related to wear, but due to the time distribution, soft tissue envelopes and surface tension may also play a role. Pre-clinical biomechanical evaluations and prospective matched cohort studies are required to draw definitive conclusions.

BACKGROUND: A recent study found that activation of disconnection and low-pressure alarms is common during mouthpiece ventilation and may represent a major limitation to its use. The aim of this bench study was: (1) to investigate the technical aspects that can influence the setting of the ventilator during mouthpiece ventilation and (2) to provide a practical setting strategy to avoid the alarm activation. METHODS: Eight life-support ventilators able to deliver volume controlled ventilation were tested in a bench study using a single-limb non-vented circuit configuration connected to a standard mouthpiece. Disconnection and apnea alarm were turned off or set at the least sensitive setting. The backup frequency was set at the lowest available level. Different tidal volumes (VT) (from 500 to 1,200 mL) were tested with the rectangular and descending flow shape. For each VT, we reported the maximum set inspiratory time (TI) that allowed preventing activation of the low-pressure alarm. The presence of auto-triggering was also surveyed. RESULTS: We found that a correct combination of VT and TI avoided the activation of disconnection and low-pressure alarms in all but 3 ventilators. One ventilator did not allow mouthpiece ventilation independently from the settings used. The inability to turn off the apnea alarm in two other ventilators led to the alarm going off in any tested conditions after 120 s without triggered breaths. Auto-triggering was seldom found and easily worked out, except for in one ventilator. CONCLUSIONS: An appropriate alarm setting and combination of VT and TI would allow the majority of the tested ventilators to be used for mouthpiece ventilation without alarm activation.

Background Exposure to magnetic fields may alter the settings of programmable ventriculoperitoneal shunt valves or even cause permanent damages to these devices. There is little information about this topic, none on live patients. Objective To investigate the effects of 1.5-tesla magnetic resonance imaging (MRI) on Hakim-Codman (HC) pressure programmable valves implanted in our hospital. Methods A single-center prospective study to assess the rate of perturbations of HC programmable valve implanted. One hundred consecutive patients implanted for different clinical reasons between 2008 and 2012 were examined. A conventional skull x-ray before and after a standard MRI on 1.5 tesla. We evaluated before and after results, analyzed modification rate, and verified eventual damages to the implanted devices. Results Implanted HC valves are extremely handy and durable, even if they are likely to change often due to the exposure to magnetic fields. None of the patients complained of heating effects. Oscillations range from 10–30 mm H 2 O with a patient who reached 50 mm H 2 O and 1 who reached 60 mm H 2 O. Global alteration rate was 40%: 10 patients (10%) experienced a 10 mm H 2 O change; 14 patients (14%) had a 20 mm H 2 O change; 6 patients (6%) had a 30 mm H 2 O change; 8 patients (8%) had a 40 mm H 2 O change; 1 patient had a 50 mm H 2 O change; and 1 patient had a 60 mm H 2 O change. Conclusions HC valves presented a variable perturbation rate, with an alteration rate of 40% with 1.5-telsa MRI. We have not observed malfunctioning hardware as a result of magnetic influence. We claim ​ a cranial x-ray immediately after the MRI because of a high risk (40%) of decalibration, especially in patients with low ventricles compliance.

An innovative epiphyseal device has been recently proposed claiming an effective bone–prosthesis load transfer and a nearly physiological bone stresses distribution. However preliminary experimental tests showed a 23% weakening of the femoral neck after implantation. Aim of this study was to revise the prosthesis geometry with the goal of enhancing the femoral neck strength after implantation, while maintaining unchanged the initial conceptual design. To this aim, the risk of femoral neck fractures, prosthesis fractures, aseptic loosening and excessive bone resorption were addressed through a validated finite element procedure following a systematic approach. The initial prosthesis geometry was revised to reduce each investigated failure risk below the threshold of acceptance (100%). The new geometry was re-assessed to verify the effectiveness of the revision. The first design was predicted to locally induce high bone strains and cement stresses, which translated in a risk of bone and cement failure exceeding the threshold of acceptance (>100%). The revised design preserved a good stability of the device, contemporary reducing the risk for bone (45%) and cement (60%) failure. If results will be confirmed by statistical and clinical experimentations, current clinical indications for hip epiphyseal devices might be extended.

Evaluation of medical devices retrieved after in vivo service provides unique evidence related to the physiological environment in which the biomaterials performed. This study implements a training procedure for evaluating polyethylene bearings of joint prostheses obtained after pre-clinical tests or explanted after in vivo function. A total of 161 damage regions on 45 bearings were evaluated by four observers. An illustrated Damage Mode Atlas was developed as a reference guide, inclusive of both photographs and concise written descriptions of 16 specific damage modes that are typical for polyethylene bearings. Utilizing the Damage Mode Atlas to train new researchers improved the damage pattern analysis, including more accurate identification of damage modes and improved inter-rater reliability. This Damage Mode Atlas is a useful supplementary tool for conducting Stage II non-destructive analysis of explanted polyethylene bearings used for joint replacement, in accordance with international guidelines for evaluating explanted medical devices.

International audience; AIMS: The aim of this study was to evaluate any benefits to the number of viable pacing vectors and maximal spatial coverage with quadripolar left ventricular (LV) leads when compared with tripolar and bipolar equivalents in patients receiving cardiac resynchronization therapy (CRT). METHODS AND RESULTS: A meta-analysis of five previously published clinical trials involving the Quartet™ LV lead (St Jude Medical, St Paul, MN, USA) was performed to evaluate the number of viable pacing vectors defined as capture thresholds ≤2.5 V and no phrenic nerve stimulation and maximal spatial coverage of viable vectors in CRT patients at pre-discharge (n = 370) and first follow-up (n = 355). Bipolar and tripolar lead configurations were modelled by systematic elimination of two and one electrode(s), respectively, from the Quartet lead. The Quartet lead with its four pacing electrodes exhibited the greatest number of pacing vectors per patient when compared with the best bipolar and the best tripolar modelled equivalents. Similarly, the Quartet lead provided the highest spatial coverage in terms of the distance between two furthest viable pacing cathodes when compared with the best bipolar and the best tripolar configurations (P \textless 0.05). Among the three modelled bipolar configurations, the lead configuration with the two most distal electrodes resulted in the highest number of viable pacing vectors. Among the four modelled tripolar configurations, elimination of the second proximal electrode (M3) resulted in the highest number of viable pacing options per patient. There were no significant differences observed between pre-discharge and first follow-up analyses. CONCLUSION: The Quartet lead with its four electrodes and the capability to pace from four anatomical locations provided the highest number of viable pacing vectors at pre-discharge and first follow-up visits, providing more flexibility in device programming and enabling continuation of CRT in more patients when compared with bipolar and tripolar equivalents

The present work aims to evaluate the mobility of the polyethylene bearing in 25 patients implanted with a mobile-bearing PCL-retaining TKR (Interax ISA, Striker Howmedica) under in vivo, weight-bearing conditions over 3 years' follow-up. We compared the bearing motion in response to specific tests in two consecutive follow-ups with Roentgen Stereophotogrammetric Analysis (RSA). Results showed that polyethylene continued to displace on the tibial baseplate over time: longitudinal rotations and medio-lateral translations tended to increase at the second follow-up (mean increases 0.7 ± 2.5° and 0.34 ± 1.08 mm, respectively), while sagittal translations did not show any relevant change. Longitudinal rotations and AP translations were preserved when present at both follow-ups. Nevertheless, no statistical evidence of repeatable pattern of motion was found, since bearings frequently reversed their pattern of motion between the two follow-ups. The unconstrained polyethylene mobility resulted in an unrepeatable, erratic pattern of bearing motion intra-patient and over time. The changes in knee motion were found not to affect the clinical results over the first 3 years of follow-up. As in a fixed-bearing design, mobile-bearing design was not able to reproduce normal knee kinematics. © 2006 Elsevier B.V. All rights reserved.

The eye lens annual dose limit for exposed personnel to ionizing radiation has recently been revised by the ICRP - International Commission on Radiological Protection and the proposed new limit has been accepted by European legislation through the Council Directive 2013/59/EURATOM 2013. Among medical exposed personnel, the staff performing interventional cardiology are usually affected by relevant doses. For this reason a survey, employing dosemeters characterized in terms of Hp(3), was performed in order to get the order of magnitude of the doses received by the eye lens, at least as a first guess. The survey showed that the annual dose limit can easily be reached if a proper radiation protection approach is not implemented. © 2015 IOP Publishing Ltd.

PURPOSE: To evaluate the correlation between corneal biomechanical and morphological data in healthy eyes. METHODS: A complete clinical eye examination of naïve eyes was followed by tomographic (Pentacam, Oculus, Wetzlar, Germany) and biomechanical (Corvis ST, Oculus, Wetzlar, Germany) evaluation. Linear regression between central corneal thickness (CCT), corneal volume (CV) and anterior corneal curvature measured with Sim'K (SK), versus corneal deformation parameters measured with Corvis ST have been run using SPSS software version 18.0. RESULTS: Seventy-six eyes of 76 healthy subjects (44 women and 32 men) with a mean age of 36.84±10.74 years and a mean refractive error of -0.55±1.68D (measured as spherical equivalent) were evaluated. Corneal deformation parameters were weakly correlated with corneal morphological parameters and with spherical equivalent. Although the correlations between deformation amplitude versus SK and between SK versus Velocity of Applanation 2, were higher than the others (R2=0.28 and 0.26 respectively), none of them was statistically significant (p>0.01). CONCLUSIONS: According with these findings, Corvis ST seems to be able to provide an analysis of corneal deformation independent from corneal morphological characteristics. If these data will be confirmed in further studies, this device could be useful in the management and screening of eyes with corneal diseases. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Kidney transplantation is the only potentially curative treatment for patient facing end-stage renal disease, and it is now routinely used. Its use is mainly limited by the supply of transplantable donor organs, which far exceeds the demand. Regenerative medicine and tissue engineering offer promising means for overcoming this shortage. In the present study, we developed and validated a protocol for producing acellular rat renal scaffolds. Left kidneys were removed from 26 male Lewis rats (weights: 250–350 g) and decellularized by means of aortic anterograde perfusion with ionic and anionic detergents (Triton X-100 1% and SDS 1%, respectively). 19 scaffolds thus obtained (and contralateral native kidneys as controls) were deeply characterized in order to evaluate the decellularization quality, the preservation of extracellular matrix components and resultant micro-angioarchitecture structure. The other 7 were transplanted into 7 recipient rats that had undergone unilateral nephrectomy. Recipients were sacrificed on post-transplantation day 7 and the scaffolds subjected to histologic studies. The dual-detergent protocol showed, with only 5 h of perfusion per organ, to obtain thoroughly decellularized renal scaffolds consisting almost exclusively of extracellular matrix. Finally the macro- and the microarchitecture of the renal parenchyma were well preserved, and the grafts were implanted with ease. Seven days after transplant, the scaffolds were morphologically intact although all vascular structures were obstructed with thrombi. Production and implantation of acellular rat renal scaffolds is a suitable platform for further studies on regenerative medicine and tissue engineering.

We report the simultaneous diffraction cancellation for beams of different wavelengths in out-of-equilibrium dipolar glass. The effect is supported by the photorefractive diffusive nonlinearity and scale-free optics, and can find application in imaging and microscopy. © 2011 Optical Society of America.

OBJECTIVE: The aim of this study was to evaluate the robustness and zero-drift of an intracranial pressure sensor, Neurovent-P (Raumedic AG, Munchberg, Germany), when used in the clinical environment. METHODS: A prospective multicenter trial, conforming to the International Organization for Standardization 14155 Standard, was conducted in 6 European BrainIT centers between July 2005 and December 2006. Ninety-nine catheters were used. The study was observational, followed by a centralized sensor bench test after catheter removal. RESULTS: The mean recorded value before probe insertion was 0.17 ± 1.1 mm Hg. Readings outside the range ± 1 mm Hg were recorded in only 3 centers on a total of 15 catheters. Complications were minimal and mainly related to the insertion bolt. The mean recorded pressure value at removal was 0.8 ± 2.2 mm Hg. No relationship was identified between postremoval reading and length of monitoring. The postremoval : bench test indicated the probability of a system failure, defined as a drift of more than 3 mm Hg, at a range between 12 and 17%. : CONCLUSION: The Neurovent-P catheter performed well in clinical use in terms of robustness. The majority of technical complications were associated with the bolt fixation technology. Adverse events were rare and clinically nonsignificant. Despite the earlier reported excellent bench test zero-drift rates, under the more demanding clinical conditions, zero-drift rate remains a concern with catheter tip strain gauge technology. This performance is similar, and not superior, to other intracranial pressure devices.

OBJECTIVE: Imperfect patient-ventilator interaction is common during assisted ventilation, and the detection of clinically relevant mismatching requires visual monitoring of the ventilator screen. We have assessed the feasibility, sensitivity and specificity of an algorithm embedded in a ventilator system that is able to automatically detect the occurrence of ineffective triggering and double triggering in real time. DESIGN: Prospective study. SETTING: Respiratory intensive care unit. METHODS: Twenty patients undergoing pressure-support ventilation, either non-invasively (NIV, n=10) or conventionally ventilated (n=10), were studied. MEASUREMENTS: The detection of ineffective triggering and double triggering from the algorithm was compared by two operators with the "real" occurrence of the phenomena as assessed using the transdiaphragmatic pressure (Pdi). RESULTS: Seven of the 20 patients exhibited gross mismatching, while in the remaining patients patient-ventilator mismatching was artificially induced using a pressure control, with a low respiratory rate. Ineffective triggering and double triggering were identified by the operators in 507 and 19 of the 3343 analyzed breaths, respectively. False positives were significantly more frequent in the NIV group than with conventional ventilation. The algorithm had an overall sensitivity of 91% and specificity of 97%. Specificity was statistically higher in the conventional ventilated group than with NIV (99% vs. 95%, p

A 2D array (PTW, type 10024), equipped with 729 vented plane parallel ion-chambers, has been calibrated as a detector for the in vivo comparison between measured and predicted portal doses for head-neck tumors. The comparison of absolute portal doses measured to ones predicted by a commercial treatment planning system within the field of view of the CT scanner, can help the delivered dose verification during different treatment fractions, in particular when the patient's present weight loss. This paper reports the preliminary results of the comparison of the portal doses measured by a PTW 2D array during several radiotherapy fractions and the predicted portal doses for seven patients undergoing head-neck tumor radiotherapy. The gamma index analysis supplied an agreement of more than 95% of the dose-point P(gamma)>95% within acceptance criteria, in terms of dose difference, DeltaD(max), and distance-agreement, Deltad(max), equal to 5% and 4mm, respectively. After the third week, one patient showed a decrease of P(gamma) values due to the markedly reduced patient's thickness. Even if the spatial resolution of the 2D array was 1cm, there were two advantages in the use of this 2D array as a portal dose device for IMRT quality control. The first one was the use of a stable and efficient absolute dosimeter for in vivo verification, although its construction and behavior for other gantry angles need to be tested, and the second one was the time efficiency in verifying the correct dose delivery in several fractions of the therapy. This study presents acceptance criteria for the comparison of TPS-predicted portal dose images with in vivo 2D ion-chamber measurements for IMRT. In particular, portal dose measurements offer clues for additional studies as to which indicators can signal the need for replanning during treatment.

Working Group on Blood Pressure Monitoring of the European Society of Hypertension International Protocol for validation of blood pressure measuring devices in adults Eoin O’Brien,Thomas Pickering, Roland Asmar, Martin Myers, Gianfranco Parati, Jan Staessen, Thomas Mengden, Yutaka Imai, Bernard Waeber and Paolo Palatini and with the statistical assistance of Neil Atkins and William Gerin, on behalf of the Working Group on Blood Pressure Monitoring of the European Society of Hypertension

Background The ultrasonic industry has recently produced echocardiographic Hand Held Devices (miniaturized, compact and battery-equipped echocardiographic systems). Their potential usefulness has been successfully assessed in a wide range of clinical conditions. The aim of the study was to verify if the routine use of a basic model of echocardiographic Hand Held Device (HHD) could be an important diagnostic tool during outpatient cardiologic consulting or in non-cardiologic hospital sections. Methods 87 consecutive patients were included in this study; they underwent routine physical examination, resting ECG and echocardiographic evaluation using a basic model of HHD performed by trained echocardiographists; the cardiologist, whenever possible, formulated a diagnosis. The percentage of subjects in whom the findings were judged reasonably adequate for final diagnostic and therapeutic conclusions was used to quantify the "conclusiveness" of HHD evaluation. Successively, all patients underwent a second echocardiographic evaluation, by an examiner with similar echocardiographic experience, performed using a Standard Echo Device (SED). The agreement between the first and the second echocardiographic exam was also assessed. Results Mean examination time was 6.7 ± 1.5 min. using HHD vs. 13.6 ± 2.4 min. using SED. The echocardiographic examination performed using HHD was considered satisfactory in 74/87 patients (85.1% conclusiveness). Among the 74 patients for whom the examination was conclusive, the diagnosis was concordant with that obtained with the SED examination in 62 cases (83.8% agreement). Conclusion HHD may generally allow a reliable cardiologic basic evaluation of outpatient or subjects admitted to non-cardiologic sections, more specifically in particular subgroups of patients, with a gain in terms of time, shortening patient waiting lists and reducing healthy costs.