A rare case of quadrileaflet mitral valve and ostium primum atrial septal defect.

A 60-year-old woman was referred to our clinic for evaluation of her rapidly progressive dyspnea, and she had no previous history of heart disease. A murmur was noted on her examination, and transthoracic echocardiography was so difficult to be performed due to poor acoustic windows so she was referred to do a transesophageal echocardiography that showed an ostium primum atrial septal defect (ASD) with left-to-right shunt and a quadrileaflet mitral valve with severe regurgitation. Later on, she underwent surgery with ostium primum ASD closure by a patch and double cleft repair by suture after right heart catheterization.

A new nonparametric test for the race model inequality.

The race model inequality (RMI), as first introduced by Miller (Cognitive Psychology, 14, 247-279, 1982), entails an upper bound on the amount of statistical facilitation for reaction times (RTs) attainable by a race model within the redundant-signals paradigm. A violation of RMI may be considered as empirical evidence for a coactivation model rather than a race model. Here, we introduce a novel nonparametric procedure for evaluating the RMI for single participant analysis. The statistical procedure is based on a new probabilistic representation that highlights some neglected, but important distributional features of the RMI. In particular, we show how the reconstructed distribution function under maximal statistical facilitation for a race model is characterized by a specific truncated-type property. The results of two Monte Carlo simulation studies suggest that our procedure efficiently controls for type I error with reasonable power. Finally, unlike previous proposals for single participant analysis (e.g., Maris and Maris (Journal of Mathematical Psychology 47, 507-514, 2003)), our approach is also more consistent with the typical way to collect RT data in experimental works. R script functions for running the statistical analysis on single participant data are made freely available to the readers on a dedicated web server.

Exercise in Patients on Dialysis: A Multicenter, Randomized Clinical Trial.

Previous studies have suggested the benefits of physical exercise for patients on dialysis. We conducted the Exercise Introduction to Enhance Performance in Dialysis trial, a 6-month randomized, multicenter trial to test whether a simple, personalized walking exercise program at home, managed by dialysis staff, improves functional status in adult patients on dialysis. The main study outcomes included change in physical performance at 6 months, assessed by the 6-minute walking test and the five times sit-to-stand test, and in quality of life, assessed by the Kidney Disease Quality of Life Short Form (KDQOL-SF) questionnaire. We randomized 296 patients to normal physical activity (control; n=145) or walking exercise (n=151); 227 patients (exercise n=104; control n=123) repeated the 6-month evaluations. The distance covered during the 6-minute walking test improved in the exercise group (mean distance±SD: baseline, 328±96 m; 6 months, 367±113 m) but not in the control group (baseline, 321±107 m; 6 months, 324±116 m; P<0.001 between groups). Similarly, the five times sit-to-stand test time improved in the exercise group (mean time±SD: baseline, 20.5±6.0 seconds; 6 months, 18.2±5.7 seconds) but not in the control group (baseline, 20.9±5.8 seconds; 6 months, 20.2±6.4 seconds; P=0.001 between groups). The cognitive function score (P=0.04) and quality of social interaction score (P=0.01) in the kidney disease component of the KDQOL-SF improved significantly in the exercise arm compared with the control arm. Hence, a simple, personalized, home-based, low-intensity exercise program managed by dialysis staff may improve physical performance and quality of life in patients on dialysis.

Analyzing spatial data from mouse tracker methodology: An entropic approach.

Mouse tracker methodology has recently been advocated to explore the motor components of the cognitive dynamics involved in experimental tasks like categorization, decision-making, and language comprehension. This methodology relies on the analysis of computer-mouse trajectories, by evaluating whether they significantly differ in terms of direction, amplitude, and location when a given experimental factor is manipulated. In this kind of study, a descriptive geometric approach is usually adopted in the analysis of raw trajectories, where they are summarized with several measures, such as maximum-deviation and area under the curve. However, using raw trajectories to extract spatial descriptors of the movements is problematic due to the noisy and irregular nature of empirical movement paths. Moreover, other significant components of the movement, such as motor pauses, are disregarded. To overcome these drawbacks, we present a novel approach (EMOT) to analyze computer-mouse trajectories that quantifies movement features in terms of entropy while modeling trajectories as composed by fast movements and motor pauses. A dedicated entropy decomposition analysis is additionally developed for the model parameters estimation. Two real case studies from categorization tasks are finally used to test and evaluate the characteristics of the new approach.

Fitness for entering a simple exercise program and mortality: a study corollary to the exercise introduction to enhance performance in dialysis (EXCITE) trial.

BACKGROUND/AIMS: In this corollary analysis of the EXCITE study, we looked at possible differences in baseline risk factors and mortality between subjects excluded from the trial because non-eligible (n=216) or because eligible but refusing to participate (n=116). METHODS: Baseline characteristics and mortality data were recorded. Survival and independent predictors of mortality were assessed by Kaplan-Meier and Cox regression analyses. RESULTS: The incidence rate of mortality was higher in non-eligible vs. eligible non-randomized patients (21.0 vs. 10.9 deaths/100 persons-year; P<0.001). The crude excess risk of death in non-eligible patients (HR 1.96; 95% CI 1.36 to 2.77; P<0.001) was reduced after adjustment for risk factors which differed in the two cohorts including age, blood pressure, phosphate, CRP, smoking, diabetes, triglycerides, cardiovascular comorbidities and history of neoplasia (HR 1.60; 95% CI 1.10 to 2.35; P=0.017) and almost nullified after including in the same model also information on deambulation impairment (HR 1.16; 95% CI 0.75 to 1.80; P=0.513). CONCLUSIONS: Deambulation ability mostly explains the difference in survival rate in non-eligible and eligible non-randomized patients in the EXCITE trial. Extending data analyses and outcome reporting also to subjects not taking part in a trial may be helpful to assess the representability of the study population.

Physical performance and clinical outcomes in dialysis patients: a secondary analysis of the EXCITE trial.

BACKGROUND/AIMS: Scarce physical activity predicts shorter survival in dialysis patients. However, the relationship between physical (motor) fitness and clinical outcomes has never been tested in these patients. METHODS: We tested the predictive power of an established metric of motor fitness, the Six-Minute Walking Test (6MWT), for death, cardiovascular events and hospitalization in 296 dialysis patients who took part in the trial EXCITE (ClinicalTrials.gov Identifier: NCT01255969). RESULTS: During follow up 69 patients died, 90 had fatal and non-fatal cardiovascular events, 159 were hospitalized and 182 patients had the composite outcome. In multivariate Cox models - including the study allocation arm and classical and non-classical risk factors - an increase of 20 walked metres during the 6MWT was associated to a 6% reduction of the risk for the composite end-point (P=0.001) and a similar relationship existed between the 6MWT, mortality (P<0.001) and hospitalizations (P=0.03). A similar trend was observed for cardiovascular events but this relationship did not reach statistical significance (P=0.09). CONCLUSIONS: Poor physical performance predicts a high risk of mortality, cardiovascular events and hospitalizations in dialysis patients. Future studies, including phase-2 EXCITE, will assess whether improving motor fitness may translate into better clinical outcomes in this high risk population.

Reconstruction of unstable, complex proximal humeral fractures with the da Vinci cage: surgical technique and outcome at 2 to 6 years.

BACKGROUND: Treatment of displaced proximal humeral fractures remains a challenge for the orthopaedic surgeon. We describe the reconstruction of such fractures with a new device designed to provide good medial cortex support and report treatment outcome. MATERIALS AND METHODS: The da Vinci device is an open triangular prism made of titanium. It is inserted in the proximal humeral cavity to stabilize the humeral head and tuberosities. Between May 2005 and December 2010, we treated 81 patients with unstable dislocated proximal fractures using this device. We report the outcome of the 69 patients monitored for at least 2 years. RESULTS: The results, based on the Constant-Murley and Disabilities of the Arm, Shoulder and Hand scores at a minimum of 2 years' follow-up, were excellent in 36 of 69 patients, good in 29, fair in 2, and poor in the remaining 2. Successful fracture healing was obtained in 68 of 69 patients, whereas the cage was removed in 1 patient 80 days after surgery because of infection. Partial vascular osteonecrosis occurred in 5 patients but was clinically symptomatic in only 1 of these. Fragment reduction was maintained during follow-up in all 68 cases. CONCLUSIONS: The da Vinci cage results in good reduction and stable fixation of displaced proximal humeral fractures, as well as in cases of humeral head dislocation and comminuted fractures. Unlike other devices and screwed plates, it does not invade the subacromial space and osteosynthesis is minimally invasive. LEVEL OF EVIDENCE: Level IV, Case Series, Treatment Study.

Signal-to-Noise Ratio Analysis for the Voltage-Mode Read-Out of Quartz Tuning Forks in QEPAS Applications.

Quartz tuning forks (QTFs) are employed as sensitive elements for gas sensing applications implementing quartz-enhanced photoacoustic spectroscopy. Therefore, proper design of the QTF read-out electronics is required to optimize the signal-to-noise ratio (SNR), and in turn, the minimum detection limit of the gas concentration. In this work, we present a theoretical study of the SNR trend in a voltage-mode read-out of QTFs, mainly focusing on the effects of (i) the noise contributions of both the QTF-equivalent resistor and the input bias resistor RL of the preamplifier, (ii) the operating frequency, and (iii) the bandwidth (BW) of the lock-in amplifier low-pass filter. A MATLAB model for the main noise contributions was retrieved and then validated by means of SPICE simulations. When the bandwidth of the lock-in filter is sufficiently narrow (BW = 0.5 Hz), the SNR values do not strongly depend on both the operating frequency and RL values. On the other hand, when a wider low-pass filter bandwidth is employed (BW = 5 Hz), a sharp SNR peak close to the QTF parallel-resonant frequency is found for large values of RL (RL > 2 MΩ), whereas for small values of RL (RL < 2 MΩ), the SNR exhibits a peak around the QTF series-resonant frequency.

Factors associated with higher fecundity in female maternal relatives of homosexual men.

INTRODUCTION: Recent evidence suggests that sexually antagonistic genetic factors in the maternal line promote homosexuality in men and fecundity in female relatives. However, it is not clear if and how these genetic factors are phenotypically expressed to simultaneously induce homosexuality in men and increased fecundity in their mothers and maternal aunts. AIMS: The aim of the present study was to investigate the phenotypic expression of genetic factors that could explain increased fecundity in the putative female carriers. METHODS: Using a questionnaire-based approach, which included also the Big Five Questionnaire personality inventory based on the Big Five theory, we investigated fecundity in 161 female European subjects and scrutinized possible influences, including physiological, behavioral, and personality factors. We compared 61 female probands who were either mothers or maternal aunts of homosexual men. One hundred females who were mothers or aunts of heterosexual men were used as controls. MAIN OUTCOME MEASURES: Personality traits, retrospective physiological and clinical data, behavior and opinions on fecundity-related issues were assessed and analyzed to illustrate possible effects on fecundity between probands and control females. RESULTS: Our analysis showed that both mothers and maternal aunts of homosexual men show increased fecundity compared with corresponding maternal female relatives of heterosexual men. A two-step statistical analysis, which was based on t-tests and multiple logistic regression analysis, showed that mothers and maternal aunts of homosexual men (i) had fewer gynecological disorders; (ii) had fewer complicated pregnancies; (iii) had less interest in having children; (iv) placed less emphasis on romantic love within couples; (v) placed less importance on their social life; (vi) showed reduced family stability; (vii) were more extraverted; and (viii) had divorced or separated from their spouses more frequently. CONCLUSIONS: Our findings are based on a small sample and would benefit from a larger replication, however they suggest that if sexually antagonistic genetic factors that induce homosexuality in males exist, the factors might be maintained in the population by contributing to increased fecundity greater reproductive health, extraversion, and a generally relaxed attitude toward family and social values in females of the maternal line of homosexual men.

The mediational effect of social support between organizational identification and employees' health: a three-wave study on the social cure model.

BACKGROUND: Recent research postulated that organizational identification plays an important role in employees' health and well-being. Building on the Social Identity Approach as a framework, we test the so-called social cure hypothesis, according to which group-based processes of social support should reduce employees' psychological distress. DESIGN AND METHODS: While there is a considerable amount of cross-sectional evidence concerning the positive role played by organizational identification in this dynamic, there is a lack of full panel studies. This study tries to fill this gap by using data from a sample of technical and administrative staff of a University in Italy at three time points (N = 96). Data were analyzed using Autoregressive Cross-Lagged Panel models. RESULTS: We found support for the hypothesized longitudinal mediational model. Specifically, strongly identified employees tend to receive more social support, and this in turn reduces psychological distress over time. CONCLUSIONS: This study is the first test of the social cure hypothesis in an organizational context that uses a panel study design. We discuss the theoretical and practical implications for management.

Individuation of object parts in aging.

Research on enumeration with isolated objects has indicated that young and older adults can report up to three elements with similar efficiency (subitizing effect). Recent studies on subitizing in young adults have shown that individuation occurs over parts of an object as efficiently as over physically disconnected objects, suggesting that spatial separation is a sufficient requirement for efficient individuation. Do young and older adults share this sufficient requirement? In two experiments, we tested for the presence of subitizing in an enumeration task with a varying number of distinct objects and object parts. In Experiment 1, results indicated the presence of a bilinear function (with an inflection point between 3 and 4 elements, a proxy for subitizing) in the response speed of young and older adults, and in both stimulus conditions. In addition, the enumeration slope in older participants was steeper for object parts than for objects in the subitizing range, possibly due to perceptual degradation (e.g., in contour detection). The pattern found generalizes to other stimuli (Experiment 2), thus highlighting the robustness of the present findings. Overall, the results indicate that while some perceptual factors (such as contour detection or curvature polarity) may hamper subitizing speed of older individuals relative to young adults, the subitizing span remains at approximately three to four elements for multiple objects and object parts in both young and older adults. Thus, individuation of multiple objects and object parts is a mechanism relatively resistant to aging.

A Bayesian brain model of adaptive behavior: an application to the Wisconsin Card Sorting Task.

Adaptive behavior emerges through a dynamic interaction between cognitive agents and changing environmental demands. The investigation of information processing underlying adaptive behavior relies on controlled experimental settings in which individuals are asked to accomplish demanding tasks whereby a hidden regularity or an abstract rule has to be learned dynamically. Although performance in such tasks is considered as a proxy for measuring high-level cognitive processes, the standard approach consists in summarizing observed response patterns by simple heuristic scoring measures. With this work, we propose and validate a new computational Bayesian model accounting for individual performance in the Wisconsin Card Sorting Test (WCST), a renowned clinical tool to measure set-shifting and deficient inhibitory processes on the basis of environmental feedback. We formalize the interaction between the task's structure, the received feedback, and the agent's behavior by building a model of the information processing mechanisms used to infer the hidden rules of the task environment. Furthermore, we embed the new model within the mathematical framework of the Bayesian Brain Theory (BBT), according to which beliefs about hidden environmental states are dynamically updated following the logic of Bayesian inference. Our computational model maps distinct cognitive processes into separable, neurobiologically plausible, information-theoretic constructs underlying observed response patterns. We assess model identification and expressiveness in accounting for meaningful human performance through extensive simulation studies. We then validate the model on real behavioral data in order to highlight the utility of the proposed model in recovering cognitive dynamics at an individual level. We highlight the potentials of our model in decomposing adaptive behavior in the WCST into several information-theoretic metrics revealing the trial-by-trial unfolding of information processing by focusing on two exemplary individuals whose behavior is examined in depth. Finally, we focus on the theoretical implications of our computational model by discussing the mapping between BBT constructs and functional neuroanatomical correlates of task performance. We further discuss the empirical benefit of recovering the assumed dynamics of information processing for both clinical and research practices, such as neurological assessment and model-based neuroscience.

A Joint Modelling Approach to Analyze Risky Decisions by Means of Diffusion Tensor Imaging and Behavioural Data.

Understanding dependencies between brain functioning and cognition is a challenging task which might require more than applying standard statistical models to neural and behavioural measures to be accomplished. Recent developments in computational modelling have demonstrated the advantage to formally account for reciprocal relations between mathematical models of cognition and brain functional, or structural, characteristics to relate neural and cognitive parameters on a model-based perspective. This would allow to account for both neural and behavioural data simultaneously by providing a joint probabilistic model for the two sources of information. In the present work we proposed an architecture for jointly modelling the reciprocal relation between behavioural and neural information in the context of risky decision-making. More precisely, we offered a way to relate Diffusion Tensor Imaging data to cognitive parameters of a computational model accounting for behavioural outcomes in the popular Balloon Analogue Risk Task (BART). Results show that the proposed architecture has the potential to account for individual differences in task performances and brain structural features by letting individual-level parameters to be modelled by a joint distribution connecting both sources of information. Such a joint modelling framework can offer interesting insights in the development of computational models able to investigate correspondence between decision-making and brain structural connectivity.

Reaching to sounds in virtual reality: A multisensory-motor approach to promote adaptation to altered auditory cues.

When localising sounds in space the brain relies on internal models that specify the correspondence between the auditory input reaching the ears, initial head-position and coordinates in external space. These models can be updated throughout life, setting the basis for re-learning spatial hearing abilities in adulthood. In addition, strategic behavioural adjustments allow people to quickly adapt to atypical listening situations. Until recently, the potential role of dynamic listening, involving head-movements or reaching to sounds, have remained largely overlooked. Here, we exploited visual virtual reality (VR) and real-time kinematic tracking, to study the role of active multisensory-motor interactions when hearing individuals adapt to altered binaural cues (one ear plugged and muffed). Participants were immersed in a VR scenario showing 17 virtual speakers at ear-level. In each trial, they heard a sound delivered from a real speaker aligned with one of the virtual ones and were instructed to either reach-to-touch the perceived sound source (Reaching group), or read the label associated with the speaker (Naming group). Participants were free to move their heads during the task and received audio-visual feedback on their performance. Most importantly, they performed the task under binaural or monaural listening. Results show that both groups adapted rapidly to monaural listening, improving sound localisation performance across trials and changing their head-movement behaviour. Reaching the sounds induced faster and larger sound localisation improvements, compared to just naming its position. This benefit was linked to progressively wider head-movements to explore auditory space, selectively in the Reaching group. In conclusion, reaching to sounds in an immersive visual VR context proved most effective for adapting to altered binaural listening. Head-movements played an important role in adaptation, pointing to the importance of dynamic listening when implementing training protocols for improving spatial hearing.

Pseudodiagnosticity revisited.

In the psychology of reasoning and judgment, the pseudodiagnosticity task has been a major tool for the empirical investigation of people's ability to search for diagnostic information. A novel normative analysis of this experimental paradigm is presented, by which the participants' prevailing responses turn out not to support the generally accepted existence of a reasoning bias. The conclusions drawn do not rest on pragmatic concerns suggesting alleged divergences between the experimenter's and participants' reading of the task. They only rely, instead, on the demonstration that observed behavior largely conforms to optimal utility maximizing information search strategies for standard variants of the pseudodiagnosticity paradigm that have been investigated so far. It is argued that the experimental results obtained, contrary to what has recurrently been claimed, have failed to discriminate between normative and nonnormative accounts of behavior. More general implications of the analysis presented for past and future research on human information search behavior and diagnostic reasoning are discussed.

Neutrophil gelatinase-associated lipocalin (NGAL) reflects iron status in haemodialysis patients.

BACKGROUND: An iron deficiency is often present in haemodialysis (HD) patients; however, although transferrin saturation (TSAT) of <20% and/or serum ferritin of <200 ng/mL should express iron scarcity, in HD patients high ferritin levels could be related to inflammation rather than reflecting optimal iron stores. METHODS: The aim of the present study was to evaluate serum levels of neutrophil gelatinase-associated lipocalin (NGAL), a small siderophore-binding protein, in a cohort of 56 chronic HD patients in order to determine its possible relationships with iron status. RESULTS: NGAL levels were markedly higher in HD patients than in healthy controls; furthermore, HD patients with TSAT <20% had lower NGAL values than healthy controls, whereas the correction of iron deficiency by means of chronic i.v. iron administration significantly increased NGAL values from baseline. Findings from univariate and multivariate analyses demonstrated that NGAL was a significant predictor of hsCRP, spKT/V and TSAT. In ROC analysis, a NGAL cut-off level of

A Dynamic Framework for Modelling Set-Shifting Performances.

Higher-order cognitive functions can be seen as a class of cognitive processes which are crucial in situations requiring a flexible adjustment of behaviour in response to changing demands of the environment. The cognitive assessment of these functions often relies on tasks which admit a dynamic, or longitudinal, component requiring participants to flexibly adapt their behaviour during the unfolding of the task. An intriguing feature of such experimental protocols is that they allow the performance of an individual to change as the task unfolds. In this work, we propose a Latent Markov Model approach to capture some dynamic aspects of observed response patterns of both healthy and substance dependent individuals in a set-shifting task. In particular, data from a Wisconsin Card Sorting Test were analysed in order to represent performance trends in terms of latent cognitive states dynamics. The results highlighted how a dynamic modelling approach can considerably improve the amount of information a researcher, or a clinician, can obtain from the analysis of a set-shifting task.

A State Space Approach to Dynamic Modeling of Mouse-Tracking Data.

Mouse-tracking recording techniques are becoming very attractive in experimental psychology. They provide an effective means of enhancing the measurement of some real-time cognitive processes involved in categorization, decision-making, and lexical decision tasks. Mouse-tracking data are commonly analyzed using a two-step procedure which first summarizes individuals' hand trajectories with independent measures, and then applies standard statistical models on them. However, this approach can be problematic in many cases. In particular, it does not provide a direct way to capitalize the richness of hand movement variability within a consistent and unified representation. In this article we present a novel, unified framework for mouse-tracking data. Unlike standard approaches to mouse-tracking, our proposal uses stochastic state-space modeling to represent the observed trajectories in terms of both individual movement dynamics and experimental variables. The model is estimated via a Metropolis-Hastings algorithm coupled with a non-linear recursive filter. The characteristics and potentials of the proposed approach are illustrated using a lexical decision case study. The results highlighted how dynamic modeling of mouse-tracking data can considerably improve the analysis of mouse-tracking tasks and the conclusions researchers can draw from them.

Efficacy and safety of once-weekly intravenous epoetin alfa in maintaining hemoglobin levels in hemodialysis patients.

BACKGROUND: Although an erythropoiesis-stimulating agent (ESA) is most frequently administered intravenously for treatment of anemia in patients with chronic kidney disease who are on dialysis, few studies have compared the efficacy of different intravenous (i.v.) dosing schedules. METHODS: This multicenter, phase IIIb, open-label, controlled study randomized 289 stable hemodialysis patients to continue with conventional dosing of i.v. epoetin alfa or darbepoetin, or to switch to once-weekly i.v. epoetin alfa at the same cumulative weekly starting dose, to maintain hemoglobin levels at 11.0-13.0 g/dL, and within 1.0 g/dL of the baseline value. Hemoglobin levels and ESA doses were recorded every 4 weeks for 28 weeks. RESULTS: Hemoglobin levels fell significantly and ESA doses increased significantly between baseline and week 28 (mean of week 16-28 values) in the once-weekly epoetin alfa group, compared with the conventional treatment group (p< 0.001). The adjusted difference in mean hemoglobin levels between the groups was 0.73 g/dL (greater than the threshold for therapeutic equivalence of 0.5 g/dL). The changes between groups from baseline was significant at all time points for hemoglobin levels (0.36, 0.46, 0.81, 0.87, 0.78, 0.62 and 0.49 g/dL) and from week 12 for ESA dose (718.5, 1,326.5, 1,732.0, 1,839.7 and 1,959.1 IU/week; p=0.005). Hemoglobin was maintained at the target level in 78% and 84% of patients on conventional dosing, and 67% and 64% of those on once-weekly epoetin alfa in the intention-to-treat (p=0.1) and per protocol (p=0.016) populations, respectively. CONCLUSIONS: This study did not show therapeutic equivalence of once-weekly i.v. epoetin alfa with conventional dosing regimens.

The block-bridge system: a new concept and surgical technique to reconstruct articular surfaces and tuberosities in complex proximal humeral fractures.

Surgical treatment of complex displaced fractures of proximal humerus has changed in the last few years. Osteosynthesis has a high rate of nonunion, malunion, and avascular necrosis, and the results of hemiarthroplasty are not always functionally satisfactory. We report the results of a new technique for the reconstruction of the proximal humerus around a triangular-shaped bone block positioned inside the head and the metaphysis. The fragments are stabilized with minimal osteosynthesis by Kirschner wires, screws, or sutures. From 2001 to 2005, we treated 33 patients (20 men, 13 women) aged 34 to 74 years. The functional results were evaluated by the Constant score, with a mean follow-up of 24 months (range,12-36 months) The mean Constant score was 68 (range, 47-90). The results were excellent or good in 23 patients. The mean active anterior elevation was 160 degrees , all were pain free, and they returned to their preoperative activities, including sports. One patient had a symptomatic avascular necrosis that was treated with a hemiarthroplasty. The results show that this new technique has good clinical results with a low percentage of complications.