Limitations in the Assessment of Prosthesis-Patient Mismatch

Background Prosthesis-patient mismatch (PPM) after aortic valve replacement (AVR) may affect survival but data are conflicting. It is assessed by relating effective orifice area (EOA) to body surface area (EOAi). EOA is patient-specific as the result of flow-velocity times area at the individual patient's outflow tract levels (LVOTA) divided by trans-prosthetic flow velocity. However, some studies use projected EOAs (i.e., valve size associated EOAs from other patient populations) to assess how PPM affects outcome.

Methods We analyzed 76 studies addressing hemodynamic outcome and/or mortality after bioprosthetic AVR.

Results In 48 studies, projected or measured EOA for calculation of EOAi and PPM assessment was used (of which 25 demonstrated an effect on survival). We identified 28 additional studies providing measured EOA values and the corresponding Bernoulli's pressure gradients after AVR. Despite EOA being a patient-specific parameter, 77% of studies assessing a PPM impact on survival used projected EOAs. The 28 studies are providing measured EOA values and the corresponding Bernoulli's pressure gradients in patients after AVR showed a highly significant, linear relationship between EOA and Bernoulli's gradient. Considering this relationship, it is surprising that relating EOA to body surface area (BSA) (EOAi) is standard but relating pressure gradients to BSA is not.

Conclusion We conclude that the majority of studies assessing PPM have used false assumptions because EOA is a patient-specific parameter and cannot be transferred to other patients. In addition, the use of EOAi to assess PPM may not be appropriate and could explain the inconsistent relation between PPM and survival in previous studies.

Weather, Weather Changes and the Risk of Bell's Palsy: A Multicenter Case-Crossover Study

BACKGROUND

To evaluate if weather or changes in weather are risk factors for Bell's palsy (BP) as exposure to draught of cold air has been popularly associated with the occurrence of BP.

METHODS

Using a multicenter hospital-based case-crossover study, we analyzed the association between ambient temperature, atmospheric pressure, relative air humidity or their 24 h changes and the risk for BP in 825 patients or subgroups.

RESULTS

One day following a 24 h increase in atmospheric pressure of more than 6 hPa, the risk for BP increased by 35% (OR 1.35; 95% CI 1.03-1.78) in the overall population. The risk for BP more than doubled in patients with diabetes mellitus after rapid variations in ambient temperature, independent of the direction (temperature decrease > 2.25°C; OR 2.15; 95% CI 1.08-4.25; temperature increase between 0.75 and 2.25°C; OR 2.88; 95% CI 1.63-5.10).

CONCLUSIONS

Our findings support the hypothesis of an association between certain weather conditions and the risk for BP with acute changes in atmospheric pressure and ambient temperature as the main risk factors. Additionally, contrasting results for risk of BP after temperature changes in the diabetic and non-diabetic subgroups support the paradigm of a diabetic facial palsy as a distinct disease entity.

[Fractures of the lateral process of the talus-snowboarder's ankle]

Fractures of the lateral tubercle of the talus (PLT) are rare. With the increasing popularity of the trend sport snowboarding, the incidence of PLT fractures has increased. The most common classification of PLT fractures is the Hawkins classification. The aim of this review was to raise awareness for the injury and discuss the current evidence. A literature search revealed eight studies, each including at least seven patients. Six out of the eight studies were descriptive, retrospective case series without predefined treatment concepts. These resulted in only moderate treatment outcomes. Due to the low number of patients, the lack of computed tomography (CT) or magnetic resonance imaging (MRI) and inconsistent treatment approaches, these studies do not allow to draw conclusions on a treatment concept for PLT fractures. The other two studies validated existing treatment regimens. Overall, surgical treatment of dislocated fractures and conservative treatment of non-dislocated fractures was carried out with satisfactory results. The outcome of conservative treatment of dislocated factures remains unclear. A reason for the inconsistent treatment results could be the observed concomitant injuries, including dislocation of the tendons of the peroneus muscles (46%), calcaneal chondral injuries (48%) and subluxation of the subtalar joint (7%). Based on the limited evidence available, the authors recommend the application of CT and MRI for PLT fractures to assess concomitant injuries, which are the primary indication for surgery. Dislocated type I and II fractures (>2 mm) should be treated operatively, type III and non-dislocated type I and II fractures can be treated conservatively by immobilization and partial weight-bearing for 6 weeks.

[Minimally invasive cheilectomy]

OBJECTIVES

Treatment of hallux rigidus by minimally invasive resection of the dorsal osteophytes, synovectomy and resection of the dorsal part of the metatarsal head.

INDICATIONS

Hallux rigidus grades II and III CONTRAINDICATIONS: End-stage osteoarthritis of the first metatarsophalangeal joint with beginning ankylosis.

SURGICAL TECHNIQUE

Osteophytes around the metatarsophalangeal joint are removed using a 1 cm incision dorsomedial, approximately 3 cm proximal of the joint space. The dorsal third of the metatarsal head is resected with a burr to improve dorsiflexion. The extent of bone resection is checked with an image intensifier. Loose bone fragments removed with a rangeur. An arthroscopy can be performed to check the completeness of bone resection, the irrigation of the joint and, if needed, to extend the synovectomy.

POSTOPERATIVE MANAGEMENT

Removal of the sutures after 2 weeks. Depending on pain, the patient can change from the postoperative shoe to a normal soft, comfortable and wide shoe after 1-2 weeks. Nonsteroidal drugs can be prescribed as needed. Active and passive mobilization of the metatarsophalangeal joint is also recommended.

RESULTS

The technique allows a soft-tissue-preserving resection of the osteophytes and a partial resection of the metatarsal head. The main advantages are limited soft-tissue trauma and rapid rehabilitation. In all, 21 women and 17 men with hallux rigidus stages II and III (Vanore) underwent surgery. Minimum follow-up was 12 months. In 1 patient, injury of the extensor hallucis longus tendon was observed. Two patients underwent revision surgery. One patient was converted to a metatarsophalangeal fusion, while another patient received a resection arthroplasty. At the latest follow-up, the AOFAS (American Orthopaedic Foot & Ankle Society) score averaged 88.7 points.

Note: Soft X-ray transmission polarizer based on ferromagnetic thin films

A transmission polarizer for producing elliptically polarized soft X-ray radiation from linearly polarized light is presented. The setup is intended for use at synchrotron and free-electron laser beamlines that do not directly offer circularly polarized light for, e.g., X-ray magnetic circular dichroism (XMCD) measurements or holographic imaging. Here, we investigate the degree of ellipticity upon transmission of linearly polarized radiation through a cobalt thin film. The experiment was performed at a photon energy resonant to the Co L₃-edge, i.e., 778 eV, and the polarization of the transmitted radiation was determined using a polarization analyzer that measures the directional dependence of photo electrons emitted from a gas target. Elliptically polarized radiation can be created at any absorption edge showing the XMCD effect by using the respective magnetic element.

Rapid increases in nitrogen oxides are associated with acute myocardial infarction: A case-crossover study

Aims High concentrations of air pollutants are associated with increased risk for myocardial infarction. The European Union has defined statutory limits for air pollutants based on upper absolute concentrations. We evaluated the association between rapid changes in air pollutants and the risk of myocardial infarction independently of absolute concentrations. Methods and results Using a hospital-based case-crossover study, effects of 24h changes of nitrogen oxides (NO_X/2), particulate matter (PM₁₀), and ozone on the risk of myocardial infarction was assessed in 693 patients. In the overall population, increases of NO_X of more than 20 µg/m³ within 24 h were associated with an increase in the risk of myocardial infarction by up to 121% (odds ratio (OR) 2.21, 95% confidence interval (CI) 1.19-4.08). Comparably, rapid increases of NO₂ of more than 8 µg/m³ tended to increase myocardial infarction risk by 73% (OR 1.73, 95% CI 0.91-3.28) while myocardial infarction risk decreased by 60% after a decrease of NO₂ concentration of more than 8 µg/m³ (OR 0.4, 95% CI 0.21-0.77), suggesting a close-to-linear association. While results for ozone concentrations were ambiguous, rapid change in PM₁₀ was not associated with myocardial infarction risk. Conclusion Dynamics and extent of increase in nitrogen oxide concentrations may be an independent risk factor for myocardial infarction. As there are currently no European Union statutory limits reflecting this dynamic variation of air pollutants on a daily basis, the results urgently call for confirming studies in different geographical regions to verify the observations.

Cellulose Acetate Butyrate: Ammonio Methacrylate Copolymer Blends as a Novel Coating in Osmotic Tablets

The objective of this work was the preparation of osmotic tablets using polymer blends of cellulose acetate butyrate (CAB) or ethylcellulose with ammonio methacrylate copolymer (Eudragit® RL). The advantage of these coatings in comparison to the traditionally used cellulose acetate is their solubility in safer organic solvents like ethanol. Polymer films were characterized with respect to their water uptake, dry mass loss, and mechanical properties. The effect of the polymer blend ratio on drug release and on the rupture force of the coating was investigated. In addition, the effect of drug solubility and content, pH and agitation rate of the release medium, and coating level and plasticizer content on the release were studied. With increased Eudragit® RL content in the coating blends, higher medium uptake of the film was observed, resulting in shorter lag times and faster drug release from the osmotic tablets. Replacing ethylcellulose with cellulose acetate butyrate as a coating material led to shorter lag times and faster drug release due to increased film permeability. In addition, CAB-based films had a higher strength and flexibility. The drug release was osmotically controlled and decreased with increasing coating level. It increased with increased drug solubility, plasticizer content, change of buffer species (acetate > phosphate), and decreased coating level. Agitation rate and drug content had no effect on the drug release. A 20% w/w coating level was sufficient for the tablet to tolerate forces of more than five times of the gastric destructive force reported in literature.

[Endoprosthesis failure in the ankle joint : Histopathological diagnostics and classification]

INTRODUCTION

Endoprostheses of the ankle joint show higher revision rates of 3.29 revisions per 100 component years. The aims of this study were the application and modification of the consensus classification of the synovia-like interface membrane (SLIM) for periprosthetic failure of the ankle joint, the etiological clarification of periprosthetic pseudocysts and a detailed measurement of proliferative activity (Ki67) in the region of osteolysis.

MATERIAL AND METHOD

Tissue samples from 159 patients were examined according to the criteria of the standardized consensus classification. Of these, 117 cases were derived from periprosthetic membranes of the ankle. The control group included 42 tissue specimens from the hip and knee joints. Particle identification and characterization were carried out using the particle algorithm. An immunohistochemical examination with Ki67 proliferation was performed in all cases of ankle pseudocysts and 19 control cases.

RESULTS

The consensus classification of SLIM is transferrable to endoprosthetic failure of the ankle joint. Periprosthetic pseudocysts with the histopathological characteristics of the appropriate SLIM subtype were detectable in 39 cases of ankle joint endoprostheses (33.3%). The mean value of the Ki67 index was 14% and showed an increased proliferation rate in periprosthetic pseudocysts of the ankle (p-value 0.02037).

CONCLUSION

In periprosthetic pseudocysts an above average higher detection rate of type 1 SLIM induced by abrasion (51.3%) with an increased Ki67 proliferation fraction (p-value 0.02037) was found, which can be interpreted as local destructive intraosseus synovialitis. This can be the reason for formation of pseudocystic osteolysis caused by high mechanical stress in ankle endoprostheses. A simplified diagnostic classification scoring system of dysfunctional endoprostheses of the ankle is proposed for collation of periprosthetic pseudocysts, ossifications and the Ki67 proliferation fraction.

Partial nephrectomy versus radical nephrectomy for clinical localised renal masses

BACKGROUND

Partial nephrectomy and radical nephrectomy are the relevant surgical therapy options for localised renal cell carcinoma. However, debate regarding the effects of these surgical approaches continues and it is important to identify and summarise high-quality studies to make surgical treatment recommendations.

OBJECTIVES

To assess the effects of partial nephrectomy compared with radical nephrectomy for clinically localised renal cell carcinoma.

SEARCH METHODS

We searched CENTRAL, MEDLINE, PubMed, Embase, Web of Science, BIOSIS, LILACS, Scopus, two trial registries and abstracts from three major conferences to 24 February 2017, together with reference lists; and contacted selected experts in the field.

SELECTION CRITERIA

We included a randomised controlled trial comparing partial and radical nephrectomy for participants with small renal masses.

DATA COLLECTION AND ANALYSIS

One review author screened all of the titles and abstracts; only citations that were clearly irrelevant were excluded at this stage. Next, two review authors independently assessed full-text reports, identified relevant studies, evaluated the eligibility of the studies for inclusion, assessed trial quality and extracted data. The update of the literature search was performed by two independent review authors. We used Review Manager 5 for data synthesis and data analyses.

MAIN RESULTS

We identified one randomised controlled trial including 541 participants that compared partial nephrectomy to radical nephrectomy. The median follow-up was 9.3 years.Based on low quality evidence, we found that time-to-death of any cause was decreased using partial nephrectomy (HR 1.50, 95% CI 1.03 to 2.18). This corresponds to 79 more deaths (5 more to 173 more) per 1000. Also based on low quality evidence, we found no difference in serious adverse events (RR 2.04, 95% CI 0.19 to 22.34). Findings are consistent with 4 more surgery-related deaths (3 fewer to 78 more) per 1000.Based on low quality evidence, we found no difference in time-to-recurrence (HR 1.37, 95% CI 0.58 to 3.24). This corresponds to 12 more recurrences (14 fewer to 70 more) per 1000. Due to the nature of reporting, we were unable to analyse overall rates for immediate and long-term adverse events. We found no evidence on haemodialysis or quality of life.Reasons for downgrading related to study limitations (lack of blinding, cross-over), imprecision and indirectness (a substantial proportion of patients were ultimately found not to have a malignant tumour). Based on the finding of a single trial, we were unable to conduct any subgroup or sensitivity analyses.

AUTHORS' CONCLUSIONS

Partial nephrectomy may be associated with a decreased time-to-death of any cause. With regards to surgery-related mortality, cancer-specific survival and time-to-recurrence, partial nephrectomy appears to result in little to no difference.

Weather as a risk factor for epileptic seizures: A case-crossover study

OBJECTIVE

Most epileptic seizures occur unexpectedly and independently of known risk factors. We aimed to evaluate the clinical significance of patients' perception that weather is a risk factor for epileptic seizures.

METHODS

Using a hospital-based, bidirectional case-crossover study, 604 adult patients admitted to a large university hospital in Central Germany for an unprovoked epileptic seizure between 2003 and 2010 were recruited. The effect of atmospheric pressure, relative air humidity, and ambient temperature on the onset of epileptic seizures under temperate climate conditions was estimated.

RESULTS

We found a close-to-linear negative correlation between atmospheric pressure and seizure risk. For every 10.7 hPa lower atmospheric pressure, seizure risk increased in the entire study population by 14% (odds ratio [OR] 1.14, 95% confidence interval [CI] 1.01-1.28). In patients with less severe epilepsy treated with one antiepileptic medication, seizure risk increased by 36% (1.36, 1.09-1.67). A high relative air humidity of >80% increased seizure risk in the entire study population by up to 48% (OR 1.48, 95% CI 1.11-1.96) 3 days after exposure in a J-shaped association. High ambient temperatures of >20°C decreased seizure risk by 46% in the overall study population (OR 0.54, 95% CI 0.32-0.90) and in subgroups, with the greatest effects observed in male patients (OR 0.33, 95% CI 0.14-0.74).

SIGNIFICANCE

Low atmospheric pressure and high relative air humidity are associated with an increased risk for epileptic seizures, whereas high ambient temperatures seem to decrease seizure risk. Weather-dependent seizure risk may be accentuated in patients with less severe epilepsy. Our results require further replication across different climate regions and cohorts before reliable clinical recommendations can be made.

Long-term effectiveness of a school-based primary prevention program for anorexia nervosa: A 7-to 8-year follow-up

PURPOSE

This is the first study to evaluate the long-term effectiveness of a school-based prevention program in Germany. The aim is to determine the long-term effects of the primary prevention program PriMa (Primary prevention of anorexia nervosa in preadolescent girls) on disordered eating and body self-esteem from childhood to young adulthood.

METHODS

PriMa was conducted and successfully evaluated in a quasi-experimental pre-post design with a control group from 2007 to 2008 consisting of 11-13year old girls (N=1508) from Thuringian schools in Germany. Seven to eight years after the intervention, the same cohort (mean age 19.8years) was invited to complete an online survey. Disordered eating (EAT-26), body self-esteem (FBeK) and BMI were assessed via self-report. The response rate at seven-to-eight-year follow-up was very low (7%). Data of N=100 girls were analyzed.

RESULTS

Concerning changes in disordered eating, results revealed no significant long-term effect of PriMa seven to eight years after the intervention. During this time, disordered eating remained stable without a significant increase or decrease. Regarding changes in body self-esteem, group courses differed significantly from each other. The results revealed a significant main effect of group, indicating significant differences in changes of body self-esteem between the intervention and the control group. Following the analysis of these changes of body self-esteem over time, it was found that the intervention group revealed an increase of body self-esteem after program participation and remained stable over time. By contrast, the control group revealed a decrease of body self-esteem over time.

CONCLUSIONS

Long-term intervention effects of PriMa could be found for body self-esteem but not for disordered eating. The findings suggest that PriMa prevented a decrease of body self-esteem from childhood to young adulthood. For a broader dissemination it is necessary to implement prevention programs consistently in school settings. In order to maintain the prevention effects, it would be interesting to investigate the effects of booster sessions which refresh the programs content on a regular basis. Furthermore, the results of this study revealed the implementation difficulties of primary prevention programs especially concerning the retention of the sample size.

[Treatment of Osteochondral Lesions in the Ankle: A Guideline from the Group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology (DGOU)]

Background: Osteochondral lesions (OCL) of the ankle are a common cause of ankle pain. Although the precise pathophysiology has not been fully elucidated, it can be assumed that a variety of factors are responsible, mainly including traumatic events such as ankle sprains. Advances in arthroscopy and imaging techniques, in particular magnetic resonance imaging (MRI), have improved the possibilities for the diagnosis of OCLs of the ankle. Moreover, these technologies aim at developing new classification systems and modern treatment strategies. Material and Methods: This article is a review of the literature. Recommendations of the group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology (DGOU) for the treatment of OCLs of the ankle are presented. The review gives a concise overview on the results of clinical studies and discusses advantages and disadvantages of different treatment strategies. Results: Non-operative treatment shows good results for selected indications in children and adolescents, especially in early stages of osteochondritis dissecans (OCD). However, surgical treatment is usually indicated in OCLs in adolescents and adults, depending on the size and location of the lesion. Various arthroscopic and open procedures are frequently employed, including reattachment of the fragment, local debridement of the lesion with fragment removal and curettage of the lesion, bone marrow-stimulation by microfracture or microdrilling (antegrade or retrograde), and autologous matrix-induced chondrogenesis (AMIC®) - with or without reconstruction of a subchondral bone defect or cyst by autologous cancellous bone grafting. Isolated subchondral cysts with an intact cartilage surface can be treated by retrograde drilling and possibly additional retrograde bone grafting. For larger defects or as salvage procedure, osteochondral cylinder transplantation (OATS® or Mosaicplasty®) or matrix-induced autologous chondrocyte transplantation (MACT) are recommended. Transplantation of so-called (osteochondral) mega grafts, such as autologous bone grafts or allografts, are used for very large osteochondral defects that cannot be reconstructed otherwise. Implantation of the so-called "small metal implants" - such as HemiCAP Talus® - is reserved for selected cases after failed primary reconstruction. Corrective osteotomies are indicated in accompanying axial malalignments. Conclusions: There are several different treatment strategies for OCLs, but clinical studies are rare and evidence is limited. Therefore, interventional studies, e.g. randomised controlled trials (RCTs), but also observational studies, e.g. based on data of the Cartilage Registry of the German Society of Orthopaedics and Traumatology (www.knorpelregister-dgou.de), are needed and are recommended by the authors.

A liquid jet setup for x-ray scattering experiments on complex liquids at free-electron laser sources

In this paper we describe a setup for x-ray scattering experiments on complex fluids using a liquid jet. The setup supports Small and Wide Angle X-ray Scattering (SAXS/WAXS) geometries. The jet is formed by a gas-dynamic virtual nozzle (GDVN) allowing for diameters ranging between 1 μm and 20 μm at a jet length of several hundred μm. To control jet properties such as jet length, diameter, or flow rate, the instrument is equipped with several diagnostic tools. Three microscopes are installed to quantify jet dimensions and stability in situ. The setup has been used at several beamlines performing both SAXS and WAXS experiments. As a typical example we show an experiment on a colloidal dispersion in a liquid jet at the X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source free-electron laser.

[Tendoscopy of the Achilles tendon. Indications, technique and results]

BACKGROUND

Endoscopic surgical techniques are nowadays standard procedures in medicine. The advantages of these minimally invasive techniques compared to open techniques are a smaller access route with reduced tissue damage, reduced scarring and often faster postoperative mobilization. Tendoscopy can be used to treat pathologies of tendons as well as of the surrounding tissues.

OBJECTIVES

This article presents the advantages of endoscopic treatment of the Achilles tendon compared to open procedures as well as the chances and limitations of tendoscopy.

MATERIAL AND METHODS

Surgical instructions for endoscopy of the Achilles tendon are presented and a review of the literature is given.

RESULTS

The literature review showed excellent results for pathologies of the paratenon and Achilles tendinitis. Compared to open surgery there was a significantly lower rate of wound healing problems. All articles reported a high reduction of pain level with an early return to sports activities. Limitations of the procedure are extensive intratendinous pathologies and alterations of tendon insertion sites.

CONCLUSION

Tendoscopy of the Achilles tendon is a safe but sometimes challenging minimally invasive technique for the treatment of paratendinopathy.

Glutamatergic dysfunction linked to energy and membrane lipid metabolism in frontal and anterior cingulate cortices of never treated first-episode schizophrenia patients

BACKGROUND

Glutamatergic dysfunction and altered membrane lipid and energy metabolism have been repeatedly demonstrated in the frontal/prefrontal and anterior cingulate cortex (ACC) in schizophrenia. Though having been already studied in animals, the presumed link between glutamatergic function and structural plasticity has not been investigated directly in the human brain yet. We measured glutamate (Glu), focal energy metabolism, and membrane phospholipid turnover to investigate main pathologies in those key brain regions of schizophrenia.

METHODS

(1)H- and (31)P-Chemical Shift Imaging (CSI) was combined in a single session to assess Glu and markers of energy (PCr, ATP) and membrane lipid (PME, PDE) metabolism in 31 neuroleptic-naïve first acute onset psychosis patients and 31 matched healthy controls. Multivariate analyses of covariance were used to assess disease effects on Glu and to investigate the impact of Glu alterations on phospholipid and energy metabolites.

RESULTS

Glu levels of patients were increased in the frontal and prefrontal cortex bilaterally and in the ACC. Higher Glu was associated with increased left frontal/prefrontal PME and right frontal/prefrontal PDE in patients, which was not observed in healthy controls. In contrast, higher Glu levels were associated with lower PCr or ATP values in the frontal/prefrontal cortex bilaterally and in the right ACC of controls. This was not observed in the right ACC and left frontal/prefrontal cortex of patients.

CONCLUSION

Frontal glutamatergic hyperactivity is disconnected from physiologically regulated energy metabolism and is associated with increased membrane breakdown in right and increased membrane restoration in left frontal and prefrontal cortical regions. As indicated by previous findings, this pathology is likely dynamic during the course of first acute illness and possibly associated with negative symptoms and cognitive impairment. Our findings underline the importance of further research on neuroprotective treatment options during the early acute or even better for the ultra-high risk state of psychotic illness.