Results of computer assisted navigation in Total Knee Arthroplasty (TKA): comparison with the conventional method

The aim of this retrospective study was to compare the clinical and radiographic results after TKA (PFC, DePuy), performed either by computer assisted navigation (CAS, Brainlab, Johnson&Johnson) or by conventional means. Material and methods: Between May and December 2006 we reviewed 36 conventional TKA performed between 2002 and 2003 (group A) and 37 navigated TKA performed between 2005 and 2006 (group B) by the same experienced surgeon. The mean age in group A was 74 years (range 62-90) and 73 (range 58-85) in group B with a similar age distribution. The preoperative mechanical axes in group A ranged from -13° varus to +13° valgus (mean absolute deviation 6.83°, SD 3.86), in group B from -13° to +16° (mean absolute deviation 5.35, SD 4.29). Patients with a previous tibial osteotomy or revision arthroplasty were excluded from the study. Examination was done by an experienced orthopedic resident independent of the surgeon. All patients had pre- and postoperative long standing radiographs. The IKSS and the WOMAC were utilized to determine the clinical outcome. Patient's degree of satisfaction was assessed on a visual analogous scale (VAS). Results: 32 of the 37 navigated TKAs (86,5%) showed a postoperative mechanical axis within the limits of 3 degrees of valgus or varus deviation compared to only 24 (66%) of the 36 standard TKAs. This difference was significant (p = 0.045). The mean absolute deviation from neutral axis was 3.00° (range -5° to +9°, SD: 1.75) in group A in comparison to 1.54° (range -5° to +4°, SD: 1.41) in group B with a highly significant difference (p = 0.000). Furthermore, both groups showed a significant postoperative improvement of their mean IKSS-values (group A: 89 preoperative to 169 postoperative, group B 88 to 176) without a significant difference between the two groups. Neither the WOMAC nor the patient's degree of satisfaction - as assessed by VAS - showed significant differences. Operation time was significantly higher in group B (mean 119.9 min.) than in group A (mean 99.6 min., p <0.000). Conclusion: Our study showed consistent significant improvement of postoperative frontal alignment in TKA by computer assisted navigation (CAS) compared to standard methods, even in the hands of a surgeon well experienced in standard TKA implantation. However, the follow-up time of this study was not long enough to judge differences in clinical outcome. Thus, the relevance of computer navigation for clinical outcome and survival of TKA remains to be proved in long term studies to justify the longer operation time. References 1 Stulberg SD. Clin Orth Rel Res. 2003;(416):177-84. 2 Chauhan SK. JBJS Br. 2004;86(3):372-7. 3 Bäthis H, et al. Orthopäde. 2006;35(10):1056-65.

Distal dendrites of frog motor neurons: a computer-aided electron microscopic study of cobalt-filled cells.

With the aid of the cobalt labelling technique, frog spinal cord motor neuron dendrites of the subpial dendritic plexus have been identified in serial electron micrographs. Computer reconstructions of various lengths (2.5-9.8 micron) of dendritic segments showed the contours of these dendrites to be highly irregular, and to present many thorn-like projections 0.4-1.8 micron long. Number, size and distribution of synaptic contacts were also determined. Almost half of the synapses occurred at the origins of the thorns and these synapses had the largest contact areas. Only 8 out of 54 synapses analysed were found on thorns and these were the smallest. For the total length of reconstructed dendrites there was, on average, one synapse per 1.2 micron, while 4.4% of the total dendritic surface was covered with synaptic contacts. The functional significance of these distal dendrites and their capacity to influence the soma membrane potential is discussed.

Benchmarking therapeutic drug monitoring software: A review of available computer tools

Therapeutic drug monitoring (TDM) aims to optimize treatments by individualizing dosage regimens based on the measurement of blood concentrations. Dosage individualization to maintain concentrations within a target range requires pharmacokinetic and clinical capabilities. Bayesian calculations currently represent the gold standard TDM approach but require computation assistance. In recent decades computer programs have been developed to assist clinicians in this assignment. The aim of this survey was to assess and compare computer tools designed to support TDM clinical activities. The literature and the Internet were searched to identify software. All programs were tested on personal computers. Each program was scored against a standardized grid covering pharmacokinetic relevance, user friendliness, computing aspects, interfacing and storage. A weighting factor was applied to each criterion of the grid to account for its relative importance. To assess the robustness of the software, six representative clinical vignettes were processed through each of them. Altogether, 12 software tools were identified, tested and ranked, representing a comprehensive review of the available software. Numbers of drugs handled by the software vary widely (from two to 180), and eight programs offer users the possibility of adding new drug models based on population pharmacokinetic analyses. Bayesian computation to predict dosage adaptation from blood concentration (a posteriori adjustment) is performed by ten tools, while nine are also able to propose a priori dosage regimens, based only on individual patient covariates such as age, sex and bodyweight. Among those applying Bayesian calculation, MM-USC*PACK© uses the non-parametric approach. The top two programs emerging from this benchmark were MwPharm© and TCIWorks. Most other programs evaluated had good potential while being less sophisticated or less user friendly. Programs vary in complexity and might not fit all healthcare settings. Each software tool must therefore be regarded with respect to the individual needs of hospitals or clinicians. Programs should be easy and fast for routine activities, including for non-experienced users. Computer-assisted TDM is gaining growing interest and should further improve, especially in terms of information system interfacing, user friendliness, data storage capability and report generation.

Computer-assisted placement technique in hip resurfacing arthroplasty: improvement in accuracy?

Freehand positioning of the femoral drill guide is difficult during hip resurfacing and the surgeon is often unsure of the implant position achieved peroperatively. The purpose of this study was to find out whether, by using a navigation system, acetabular and femoral component positioning could be made easier and more precise. Eighteen patients operated on by the same surgeon were matched by sex, age, BMI, diagnosis and ASA score (nine patients with computer assistance, nine with the regular ancillary). Pre-operative planning was done on standard AP and axial radiographs with CT scan views for the computer-assisted operations. The final position of implants was evaluated by the same radiographs for all patients. The follow-up was at least 1 year. No difference between both groups in terms of femoral component position was observed (p > 0.05). There was also no difference in femoral notching. A trend for a better cup position was observed for the navigated hips, especially for cup anteversion. There was no additional operating time for the navigated hips. Hip navigation for resurfacing surgery may allow improved visualisation and hip implant positioning, but its advantage probably will be more obvious with mini-incisions than with regular incision surgery.

Sacred Music, Sacred Journeys : What Makes an Event Postcolonial?

Fanon, Senghor, and Ela took a radical stance in criticising the structures and mechanisms of power in hegemonic situations and relations between colonial subjects and colonial masters. They aimed to liberate African societies by decolonising the mind, culture and religion of colonial subjects. In this respect, we are concerned with the continuities and ruptures of the colonial encounter and its unequal relationships. Switzerland does not have an official colonial history and yet, Swiss companies and migrants were and are part of the world's colonies. In our contribution, we question what makes an event postcolonial : in other words, how are postcolonial relations negotiated in Switzerland? We discuss this question by analysing two annual sacred journeys in Switzerland that have been invented for and by African Christians (clerics and laity) together with the leaders of the Swiss Catholic church : one to the relics of African saints in St. Maurice, canton Valais and the other to the Black Madonna, the Virgin Mary of Einsiedeln, in the canton Schwyz. These events are empowered by the performance of African choirs - their music, dance, and costumes - but to which end and in which way?

Hyperventilation in anticipatory music performance anxiety

Objectives and Methods: Self-report studies have shown an association between music performance anxiety (MPA) and hyperventilation complaints. However, hyperventilation was never assessed physiologically in MPA. This study investigated the self-reported affective experience, self-reported physiological symptoms, and cardiorespiratory variables including partial pressure of end-tidal CO(2) (Petco(2)), which is an indicator for hyperventilation, in 67 music students before a private and a public performance. The response coherence between these response domains was also investigated.ResultsFrom the private to the public session, the intensity of all self-report variables increased (all p values < .001). As predicted, the higher the musician's usual MPA level, the larger were these increases (p values < .10). With the exception of Petco(2), the main cardiorespiratory variables also increased from the private to the public session (p values < .05). These increases were not modulated by the usual MPA level (p values > .10). Petco(2) showed a unique response pattern reflected by an MPA-by-session interaction (p < .01): it increased from the private to the public session for musicians with low MPA levels and decreased for musicians with high MPA levels. Self-reported physiological symptoms were related to the self-reported affective experience (p values < .05) rather than to physiological measures (p values > .17).ConclusionsThese findings show for the first time how respiration is stimulated before a public performance in music students with different MPA levels. The hypothesis of a hyperventilation tendency in high-performance-anxious musicians is supported. The response coherence between physiological symptoms and physiological activation is weak.

A multi-perspective approach to performance anxiety in music students

AbstractPerforming publicly has become increasingly important in a variety of professions. This condition is associated with performance anxiety in almost all performers. Whereas some performers successfully cope with this anxiety, for others it represents a major problem and even threatens their career. Musicians and especially music students were shown to be particularly affected by performance anxiety.Therefore, the goal of this PhD thesis was to gain a better understanding of performance anxiety in university music students. More precisely, the first part of this thesis aimed at increasing knowledge on the occurrence, the experience, and the management of performance anxiety (Article 1). The second part aimed at investigating the hypothesis that there is an underlying hyperventilation problem in musicians with a high level of anxiety before a performance. This hypothesis was addressed in two ways: firstly, by investigating the association between the negative affective dimension of music performance anxiety (MPA) and self-perceived physiological symptoms that are known to co-occur with hyperventilation (Article 2) and secondly, by analyzing this association on the physiological level before a private (audience-free) and a public performance (Article 3). Article 4 places some key variables of Article 3 in a larger context by jointly analyzing the phases before, during, and after performing.The main results of the self-report data show (a) that stage fright is experienced as a problem by one-third of the surveyed students, (b) that the students express a considerable need for more help to better cope with it, and (c) that there is a positive association between negative feelings of MPA and the self-reported hyperventilation complaints before performing. This latter finding was confirmed on the physiological level in a tendency of particularly high performance-anxious musicians to hyperventilate. Furthermore, the psycho-physiological activation increased from a private to a public performance, and was higher during the performances than before or after them. The physiological activation was mainly independent of the MPA score. Finally, there was a low response coherence between the actual physiological activation and the self-reports on the instantaneous anxiety, tension, and perceived physiological activation.Given the high proportion of music students who consider stage fright as a problem and given the need for more help to better cope with it, a better understanding of this phenomenon and its inclusion in the educational process is fundamental to prevent future occupational problems. On the physiological level, breathing exercises might be a good means to decrease - but also to increase - the arousal associated with a public performance in order to meet an optimal level of arousal needed for a good performance.

A randomized controlled trial of the effectiveness of a Computer-Assisted Cognitive Remediation (CACR) program in adolescents with psychosis or at high risk of psychosis: Short term and long term outcomes

The present study investigates the short- and long-term outcomes of a computer-assisted cognitive remediation (CACR) program in adolescents with psychosis or at high risk. 32 adolescents participated in a blinded 8-week randomized controlled trial of CACR treatment compared to computer games (CG). Clinical and neuropsychological evaluations were undertaken at baseline, at the end of the program and at 6-month. At the end of the program (n = 28), results indicated that visuospatial abilities (Repeatable Battery for the Assessment of Neuropsychological Status, RBANS; P = .005) improved signifi cantly more in the CACR group compared to the CG group. Furthermore, other cognitive functions (RBANS), psychotic symptoms (Positive and Negative Symptom Scale) and psychosocial functioning (Social and Occupational Functioning Assessment Scale) improved signifi cantly, but at similar rates, in the two groups. At long term (n = 22), cognitive abilities did not demonstrated any amelioration in the control group while, in the CACR group, signifi cant long-term improvements in inhibition (Stroop; P = .040) and reasoning (Block Design Test; P = .005) were observed. In addition, symptom severity (Clinical Global Improvement) decreased signifi cantly in the control group (P = .046) and marginally in the CACR group (P = .088). To sum up, CACR can be successfully administered in this population. CACR proved to be effective over and above CG for the most intensively trained cognitive ability. Finally, on the long-term, enhanced reasoning and inhibition abilities, which are necessary to execute higher-order goals or to adapt behavior to the ever-changing environment, were observed in adolescents benefi ting from a CACR.