FINITE ELEMENT ANALYSIS OF MAXILLARY BONE STRESS CAUSED BY ARAMANY CLASS IV OBTURATOR PROSTHESES

Statement of problem. The retention of an Aramany Class IV removable partial dental prosthesis can be compromised by a lack of support. The biomechanics of this obturator prosthesis result in an unusual stress distribution on the residual maxillary bone. Purpose. This study evaluated the biomechanics of an Aramany Class IV obturator prosthesis with finite element analysis and a digital 3-dimensional (3-D) model developed from a computed tomography scan; bone stress was evaluated according to the load placed on the prosthesis. Material and methods. A 3-D model of an Aramany Class IV maxillary resection and prosthesis was constructed. This model was used to develop a finite element mesh. A 120 N load was applied to the occlusal and incisal platforms corresponding to the prosthetic teeth. Qualitative analysis was based on the scale of maximum principal stress; values obtained through quantitative analysis were expressed in MPa. Results. Under posterior load, tensile and compressive stresses were observed; the tensile stress was greater than the compressive stress, regardless of the bone region, and the greatest compressive stress was observed on the anterior palate near the midline. Under an anterior load, tensile stress was observed in all of the evaluated bone regions; the tensile stress was greater than the compressive stress, regardless of the bone region. Conclusions. The Aramany Class IV obturator prosthesis tended to rotate toward the surgical resection when subjected to posterior or anterior loads. The amount of tensile and compressive stress caused by the Aramany Class IV obturator prosthesis did not exceed the physiological limits of the maxillary bone tissue. (J Prosthet Dent 2012;107:336-342)

Oxidative stress and inflammatory response increase during coronary artery bypass grafting with extracorporeal circulation

INTRODUCTION: Thiobarbituric acid-reactive substance is a marker of oxidative stress and has cytotoxic and genotoxic actions. C- reactive protein is used to evaluate the acute phase of inflammatory response. OBJECTIVES: To assess the thiobarbituric acid-reactive substance and C-reactive protein levels during extracorporeal circulation in patients submitted to cardiopulmonary bypass. METHODS: Twenty-five consecutive surgical patients (16 men and nine women; mean age 61.2 ± 9.7 years) with severe coronary artery disease diagnosed by angiography scheduled for myocardial revascularization surgery with extracorporeal circulation were selected. Blood samples were collected immediately before initializing extracorporeal circulation, T0; in 10 minutes, T10; and in 30 minutes, T30. RESULTS: The thiobarbituric acid-reactive substance levels increased after extracorporeal circulation (P=0.001), with average values in T0=1.5 ± 0.07; in T10=5.54 ± 0.35; and in T30=3.36 ± 0.29 mmoles/mg of serum protein. The C-reactive protein levels in T0 were negative in all samples; in T10 average was 0.96 ± 0.7 mg/dl; and in T30 average was 0.99 ± 0.76 mg/dl. There were no significant differences between the dosages in T10 and T30 (P=0.83). CONCLUSIONS: C-reactive protein and thiobarbituric acid-reactive substance plasma levels progressively increased during extracorporeal circulation, with maximum values of thiobarbituric acid-reactive substance at 10 min and of Creactive protein at 30 min. It suggests that there are an inflammatory response and oxidative stress during extracorporeal circulation.

Geometrical optimization of a short-stem hip implant for the reduction of proximal stress shielding (ottimizzazione geometrica di uno stelo corto di protesi d?anca per la riduzione della schermatura del carico prossimale)

Nowadays the number of hip joints arthroplasty operations continues to increase because the elderly population is growing. Moreover, the global life expectancy is increasing and people adopt a more active way of life. For this reasons, the demand of implant revision operations is becoming more frequent. The operation procedure includes the surgical removal of the old implant and its substitution with a new one. Every time a new implant is inserted, it generates an alteration in the internal femur strain distribution, jeopardizing the remodeling process with the possibility of bone tissue loss. This is of major concern, particularly in the proximal Gruen zones, which are considered critical for implant stability and longevity. Today, different implant designs exist in the market; however there is not a clear understanding of which are the best implant design parameters to achieve mechanical optimal conditions. The aim of the study is to investigate the stress shielding effect generated by different implant design parameters on proximal femur, evaluating which ranges of those parameters lead to the most physiological conditions.

Prevalence of burnout among surgical residents and surgeons in Switzerland

Burnout is a pathologic reaction in response to long-term work-related stress. The aim of this study was 2-fold: first, to assess the prevalence and degree of burnout among surgical residents and surgeons in Switzerland and, second, to identify predictors of burnout in the surgical community. Four hundred five of 618 anonymous questionnaires (65.5%) were returned. Among respondents, 3.7% and 35.1% showed high and moderate degrees of burnout, respectively. Respondents with high and moderate degrees of burnout had higher summary scores of perceived stress (P < .001). In multiple logistic regression analysis, the strongest predictors of burnout were poor interaction with nurses, disturbances due to telephone consultations, and high overall workload. To reduce burnout, new work models should be sought, in addition to decreasing work intensity and workload rather than restricting work hours alone.

Oxidative stress precedes peak systemic inflammatory response in pediatric patients undergoing cardiopulmonary bypass operation

Oxidative stress seems to contribute to cardiopulmonary bypass (CPB)-related postoperative complications. Pediatric patients are particularly prone to these complications. With this in mind, we measured oxidative stress markers in blood plasma of 20 children undergoing elective heart surgery before, during, and up to 48 h after cessation of CPB, along with inflammatory parameters and full analysis of iron status. Ascorbate levels were decreased by approximately 50% (P < 0.001) at the time of aorta cross-clamp removal (or pump switch-off in 4 patients with partial CPB), and associated with corresponding increases in dehydroascorbate (P < 0.001, r = -0.80) and malondialdehyde (P < 0.01, r = -0.59). In contrast to the immediate oxidative response, peak levels of IL-6 and IL-8 were not observed until 3-12 h after CPB cessation. The early loss of ascorbate correlated with duration of CPB (P < 0.002, r = 0.72), plasma hemoglobin after cross-clamp removal (P < 0.001, r = 0.70), and IL-6 and IL-8 levels at 24 and 48 h after CPB (P < 0.01), but not with postoperative lactate levels, strongly suggesting that hemolysis, and not inflammation or ischemia, was the main cause of early oxidative stress. The correlation of ventilation time with early changes in ascorbate (P < 0.02, r = 0.55), plasma hemoglobin (P < 0.01, r = 0.60), and malondialdehyde (P < 0.02, r = 0.54) suggests that hemolysis-induced oxidative stress may be an underlying cause of CPB-associated pulmonary dysfunction. Optimization of surgical procedures or therapeutic intervention that minimize hemolysis (e.g., off-pump surgery) or the resultant oxidative stress (e.g., antioxidant treatment) should be considered as possible strategies to lower the rate of postoperative complications in pediatric CPB.

Correction of erosion after suburethral sling insertion for stress incontinence: results and related sexual function

BACKGROUND: Suburethral slings are commonly used for the surgical treatment of female stress incontinence; occasionally they can cause erosion and dyspareunia. OBJECTIVES: The primary aim of this study is to determine the outcome after reclosure of the vaginal epithelium for suburethral sling erosion. Sexual function was assessed before and after intervention using the Female Sexual Function Index (FSFI) questionnaire. DESIGN, SETTING, AND PARTICIPANTS: This was a prospective case-controlled study in which, between December 2005 and December 2007, we included patients who were referred to the Department of Urogynaecology because of vaginal erosion after suburethral sling insertion for urinary stress incontinence. For evaluation of sexual function, all patients filled in an FSFI questionnaire before intervention and at follow-up. All patients underwent gynaecological examination including colposcopy, and the site and size of the defect were noted. INTERVENTION: The edge of the vaginal epithelium was trimmed, mobilized, and closed with interrupted vertical Vicryl mattress sutures in a single layer. MEASUREMENTS: FSFI questionnaire and clinical findings. RESULTS AND LIMITATIONS: Twenty-one patients were included in the study. Eighteen patients with larger defects were operated on, and three defects healed after topical application of estrogen cream. In 16 patients, the defect had healed at follow-up; two patients with persisting defects were brought back to surgery and the procedure was repeated, paying particular attention to tension-free adaptation of vaginal tissue. In one patient, partial sling removal was performed after the second failed intervention. The domains of desire (p<0.0001), arousal (p<0.0003), lubrication (p<0.0001), satisfaction (p<0.0130), and pain (p<0.0001) improved significantly. Orgasm remained unchanged (p=0.4130; all two-tailed t-test). CONCLUSION: Suburethral erosion can be treated effectively by resuturing. Sexual function is improved in regard to desire, arousal, lubrication, satisfaction, and pain, but not orgasm. In septic patients and patients with a history of radiation, grossly infected tissue, or severe pain, excision of the mesh needs to be considered.

Teamwork reduces physiological stress in junior surgeons

Objective: The quality of teamwork depends not only on communication skills but also on team familiarity and hierarchical structures. The aim of the present study is to evaluate the physiological impact of close teamwork between senior and junior surgeons performing elective open abdominal surgery for six months in stable teams. Methods: Physiological measurements of the main and junior surgeons were taken in a total of 40 procedures. Cumulative stress was assessed by the mea- surements of urine catecholamines (Adrenaline, Noradrenaline, Dopamine, Metanephrine, Normetanephrine). Heart rate variability was measured to assess temporal aspects of stress. The procedures were observed by a trained team of work psychologists. Direct observations of distractors, team inter- actions and communication were performed. Specific questionnaires were filled by members of the surgical team that include surgeons, nurses and anesthetists. Results: In junior surgeons, physiological stress is reduced over a period of close collaboration. Case-related communication is not stressful. However, tension within the surgical team is associated with increased levels of cat- echolamine in the urine of the senior surgeon. The difficulty of the oper- ation impacts on heart-rate variability of the junior but not of the senior surgeon. Conclusion: Junior surgeons may require months of teamwork within one stable team in order to reduce levels of physiological stress. Senior surgeons are more resistant to stressful clinical situations compared to junior surgeons but are vulnerable to tension within the surgical team.

Protrusio acetabuli: joint loading with severe pincer impingement and its theoretical implications for surgical therapy

Severe pincer impingement (acetabular protrusio) is an established cause of hip pain and osteoarthritis. The proposed underlying pathomechanism is a dynamic pathological contact of the prominent acetabular rim with the femoral head-neck junction. However, this cannot explain the classically described medial osteoarthritis in these hips. We therefore asked: (1) Does an overload exist in the medial aspect of the protrusio joint? and (2) What is the influence of three contemporary joint-preserving procedures on load distribution in protrusio hips? In vivo force and motion data for walking and standing to sitting were applied to six 3D finite element models (normal, dysplasia, protrusio, acetabular rim trimming, acetabular reorientation, and combined reorientation/rim trimming). Compared with dysplasia, the protrusio joint resulted in opposite patterns of von Mises stress and contact pressure during walking. In protrusio hips, we found an overload at the medial margin of the lunate surface (54% higher than normal). Isolated rim trimming further increased the medial overload (up to 28% higher than protrusio), whereas acetabular reorientation with/without rim trimming reduced stresses by up to 25%. Our results can be used as an adjunct for surgical decision making in the treatment of acetabular protrusio.

Non-surgical treatment of pain associated with posterior tibial tendon dysfunction: study protocol for a randomised clinical trial

BACKGROUND Symptoms associated with pes planovalgus or flatfeet occur frequently, even though some people with a flatfoot deformity remain asymptomatic. Pes planovalgus is proposed to be associated with foot/ankle pain and poor function. Concurrently, the multifactorial weakness of the tibialis posterior muscle and its tendon can lead to a flattening of the longitudinal arch of the foot. Those affected can experience functional impairment and pain. Less severe cases at an early stage are eligible for non-surgical treatment and foot orthoses are considered to be the first line approach. Furthermore, strengthening of arch and ankle stabilising muscles are thought to contribute to active compensation of the deformity leading to stress relief of soft tissue structures. There is only limited evidence concerning the numerous therapy approaches, and so far, no data are available showing functional benefits that accompany these interventions. METHODS After clinical diagnosis and clarification of inclusion criteria (e.g., age 40-70, current complaint of foot and ankle pain more than three months, posterior tibial tendon dysfunction stage I & II, longitudinal arch flattening verified by radiography), sixty participants with posterior tibial tendon dysfunction associated complaints will be included in the study and will be randomly assigned to one of three different intervention groups: (i) foot orthoses only (FOO), (ii) foot orthoses and eccentric exercise (FOE), or (iii) sham foot orthoses only (FOS). Participants in the FOO and FOE groups will be allocated individualised foot orthoses, the latter combined with eccentric exercise for ankle stabilisation and strengthening of the tibialis posterior muscle. Participants in the FOS group will be allocated sham foot orthoses only. During the intervention period of 12 weeks, all participants will be encouraged to follow an educational program for dosed foot load management (e.g., to stop activity if they experience increasing pain). Functional impairment will be evaluated pre- and post-intervention by the Foot Function Index. Further outcome measures include the Pain Disability Index, Visual Analogue Scale for pain, SF-12, kinematic data from 3D-movement analysis and neuromuscular activity during level and downstairs walking. Measuring outcomes pre- and post-intervention will allow the calculation of intervention effects by 3×3 Analysis of Variance (ANOVA) with repeated measures. DISCUSSION The purpose of this randomised trial is to evaluate the therapeutic benefit of three different non-surgical treatment regimens in participants with posterior tibial tendon dysfunction and accompanying pes planovalgus. Furthermore, the analysis of changes in gait mechanics and neuromuscular control will contribute to an enhanced understanding of functional changes and eventually optimise conservative management strategies for these patients. TRIAL REGISTRATION ClinicalTrials.gov Protocol Registration System: ClinicalTrials.gov ID NCT01839669.

Standardized pelvic floor exercises improve stress urinary incontinence in women with intrinsic sphincter deficiency.

OBJECTIVES Pelvic floor rehabilitation is the conservative therapy of choice for women with stress urinary incontinence (SUI). The success rate of surgical procedures in SUI patients with intrinsic sphincter deficiency (ISD) is low. The aim of this study was to analyse the effect of a standardized physiotherapy on patients with SUI and normotonic urethra and ISD. METHODS In this study, 64 patients with ISD and 69 patients with normotonic urethra were enrolled. Maximum urethral pressure (MUCP) >20 cm H2 O was considered as normotonic urethral pressure. Before and after physiotherapy MUCP was measured and cough testing was performed. Additionally, patient reported outcome was assessed using the King's Health Questionnaire (KHQ). For statistical analyses Excel 2010 (Microsoft Inc; Redmond, Washington) and SPSS 20 (SPSS Inc; Chicago, Illinois) for Windows were used. Power calculation was based on the primary endpoint incontinence impact and general health. For power calculation, GraphPad Statmate version 2.00 for Windows was used. RESULTS Sixty-four patients with ISD and 69 patients with normotonic urethra were included in the study. In SUI patients with normotonic and hypotonic urethra KHQ-scores regarding the primary endpoins "general health" and "incontinence impact" significantly improved following standardized physiotherapy. In both groups MUCP increased after physiotherapy. In SUI patients with ISD standardized physiotherapy resulted in a decreased incidence of a positive cough test. CONCLUSIONS Standardized physiotherapy should be offered to patients with SUI and ISD. Long-term results are subject to future studies. Neurourol. Urodynam. © 2015 Wiley Periodicals, Inc.

Dissection moléculaire de la sénescence cellulaire induite par le stress et la thérapie dans le cancer de l’ovaire et son impact sur la réponse des patientes

Le cancer de l’ovaire (COv) est le cancer gynécologique le plus létal chez la femme et les traitements existants, chirurgie et chimiothérapie, ont peu évolué au cours des dernières décennies. Nous proposons que la compréhension des différents destins cellulaires tels que la sénescence que peuvent choisir les cellules du cancer de l’ovaire en réponse à la chimiothérapie pourrait conduire à de nouvelles opportunités thérapeutiques. La sénescence cellulaire a été largement associée à l’activité de la protéine TP53, qui est mutée dans plus de 90% des cas de cancer de l’ovaire séreux de haut grade (COv-SHG), la forme la plus commune de la maladie. Dans nos travaux, à partir d’échantillons dérivés de patientes, nous montrons que les cultures primaires du cancer de l’ovaire séreux de haut grade exposées au stress ou à des drogues utilisées en chimiothérapie entrent en senescence grâce à l’activité d’un isoforme du gène CDKN2A (p16INK4A). Dans ces cellules, nous avons évalué les caractéristiques fondamentales de la sénescence cellulaire tels que les altérations morphologiques, l’activité béta galactosidase associée à la sénescence, les dommages à l’ADN, l’arrêt du cycle cellulaire et le phénotype sécrétoire associé à la sénescence. En utilisant des micromatrices tissulaires construites à partir d’échantillons humains de COv-SHG pré- et post-chimiothérapie, accompagnées de leurs données cliniques, nous avons quantifié des marqueurs de sénescence incluant une diminution de la prolifération cellulaire quelques semaines après chimiothérapie. De façon intéressante, l’expression de p16INK4A dans les échantillons de COv-SHG prétraitement corrèle avec une survie prolongée des patientes suite au traitement. Ceci suggère ainsi pour la première fois un impact biologique bénéfique pour la présence de cellules cancéreuses qui sont capable d’activer la sénescence, particulièrement pour le traitement du cancer de l’ovaire. Dans le but de complémenter les thérapies actuelles avec des approches de manipulation pharmacologique de la sénescence, nos résultats suggèrent qu’il serait important de déterminer l’impact positif ou négatif de la sénescence induite par la thérapie sur la progression de la maladie et la survie, pour chaque type de cancer de façon indépendante.

Pubovaginal sling versus transurethral Macroplastique for stress urinary incontinence and intrinsic sphincter deficiency: a prospective randomised controlled trial

Objective To compare the pubovaginal sling and transurethral Macroplastique in the treatment of female stress urinary incontinence (SUI) and intrinsic sphincter deficiency (ISD). Design A prospective randomised controlled trial comparing two surgical treatments for SUI and ISD. Setting Tertiary referral urogynaecology unit in Australia. Population Women with SUI and ISD who were suitable for either surgical technique. Methods Forty-five women with SUI and ISD were randomly allocated the pubovaginal sling (n = 22) or transurethral Macroplastique (n = 23). Subjective and objective success rates, patient satisfaction and cost measurements at six months and one year following surgery were the primary outcome measures. A telephone questionnaire survey was performed at a mean follow up period of 62 months (43-71). Main outcome measure Comparison of success rates, complications and costs. Results The symptomatic and patient satisfaction success rates were similar following the sling and Macroplastique with the objective success rate being significantly greater (P < 0.001) following the sling (81% vs 9%). Macroplastique had significantly lower morbidity but was more expensive than the sling (P < 0.001). Response rate at 62 months follow up was 60% in both groups with the sling group reporting better continence success (69% vs 21%) and satisfaction rates (69% vs 29%, P = 0.057). Conclusions The pubovaginal sling was more effective and economical than transurethral Macroplastique for the treatment of SUI and ISD. However, transurethral Macroplastique remains an appropriate treatment in selected cases of SUI and ISD.

Arterial entrapment syndrome in the cubital fossa: a rare cause of acute stress-related arterial thrombosis in a patient with brachial artery duplication

Arterial entrapment syndrome (AES) at elbow level is very rare and to our knowledge no case of AES by lacertus fibrosus in the cubital fossa in presence of brachial artery duplication has been described to date. We describe a rare case of acute arterial thrombosis of one of two brachial arteries highlighted in the cubital fossa which developed after strenuous right elbow flexor muscle activity and hyper-extensions presumably related to AES by lacertus fibrosus at elbow level. A 43-year-old right-handed woman, experienced paleness, coldness and numbness of the right hand, after 8 consecutive hours of gardening. As she worked, her ipsilateral flexor elbow muscles remained in prolonged and inappropriate tension. Clinical examination evidenced the absence of radial artery pulse in the wrist and mild hypothermia in the second and third finger. During surgical exploration two anastomosed brachial arteries were detected in the cubital fossa under the lacertus fibrosus. The lateral superficial brachial artery was occluded. Intraoperative arteriography evidenced brachial artery duplication at the third superior of the arm and normal vascular pattern at the forearm level. In cases of unexplained atypical intermittent upper extremity claudication or acute ischemic symptoms an AES should always be ruled out, particularly when symptoms are exacerbated by strenuous upper extremity activity or when upper limb muscular hypertrophy is evident. In these cases a thorough dynamic clinical and instrumental examination is mandatory to confirm a diagnosis of AES and to avoid possible future ischemic complications.

Avaliação da resposta ao stress de gatas hospitalizadas no período pós-cirúrgico em distintas condições de macroambiente

Dissertação de Mestrado Integrado em Medicina Veterinária