Vector-apodizing phase plate coronagraph: design, current performance, and future development [Invited].

Over the last decade, the vector-apodizing phase plate (vAPP) coronagraph has been developed from concept to on-sky application in many high-contrast imaging systems on 8 m class telescopes. The vAPP is a geometric-phase patterned coronagraph that is inherently broadband, and its manufacturing is enabled only by direct-write technology for liquid-crystal patterns. The vAPP generates two coronagraphic point spread functions (PSFs) that cancel starlight on opposite sides of the PSF and have opposite circular polarization states. The efficiency, that is, the amount of light in these PSFs, depends on the retardance offset from a half-wave of the liquid-crystal retarder. Using different liquid-crystal recipes to tune the retardance, different vAPPs operate with high efficiencies (${\gt}96\%$) in the visible and thermal infrared (0.55 µm to 5 µm). Since 2015, seven vAPPs have been installed in a total of six different instruments, including Magellan/MagAO, Magellan/MagAO-X, Subaru/SCExAO, and LBT/LMIRcam. Using two integral field spectrographs installed on the latter two instruments, these vAPPs can provide low-resolution spectra (${\rm{R}} \sim 30$) between 1 µm and 5 µm. We review the design process, development, commissioning, on-sky performance, and first scientific results of all commissioned vAPPs. We report on the lessons learned and conclude with perspectives for future developments and applications.

Posterolateral plate fixation with Pantalarlock® is more stable than nail fixation in tibiotalocalcaneal arthrodesis in a biomechanical cadaver study.

BACKGROUND: Despite the promising results of ankle joint arthroplasty, the tibiotalocalcaneal (TTC) arthrodesis remains an established procedure in treatment of combined pathology of the ankle and subtalar joint. Despite the promising results in biomechanical investigations, nonunion rates of up to 24% are described in recent studies. The objective of this work was a comparative study of the biomechanical properties of the posterolateral plate fixation with retrograde intramedullary nail fixation. METHODS: Twenty four fresh-frozen human lower leg specimens (12 pairs) were used for the comparative biomechanical testing. Every specimen was preconditioned with 100 N over 200 cycles. After every 250 cycles the force was increased by 50 N from 200 to 600 N. This was followed by cyclic loading in dorsi-/plantiflexion with 800 N for 3000 cycles. All specimens were subjected to bone densitometry (DXA) and computed tomography. RESULTS: Significantly higher number of spacimens with nails (4) failed during the cycling testing in dorsi-/plantarflexion and futher two during the cyclic testing with 800 N. Two specimens with plates failed during the cyclic testing with 800 N. Statistical analysis showed that the specimens with the plate were significantly more stable in each test direction. The Pearson correlation demonstrated for the specimens with plate a linear relationship between the stiffness and the determined bone density. CONCLUSIONS: The results demonstrate a significantly superior stiffness of the Pantalarlock®-plate in all testing directions compared with the HAN nail. Probably the position of the plate on the tension side of the joint and the combination of locking and lag screws provide the higher stiffness of the plate system. The correlation of the stiffness with bone density leads to more predictable results of the plate arthrodesis. We hope for a reduction of the pseudarthrosis rate and shorten the postoperative treatment phase. The authors expect advantages in the treatment of high risk patients with severe deformity of the ankle, bone defects, neuropathic deformity, poor bone quality and osteoporosis.

Acetabular Fractures in an Advanced Age - Current Knowledge and Treatment Options.

The demographic change in industrial countries leads to an increasing population that sustains an acetabular fracture in an advanced age. Some authors predicted elderly individuals to be the most rapidly growing subgroup of patients currently sustaining acetabular fractures. Gold standard of treatment of acetabular fractures remains the open reduction and internal fixation. Relevant factors impeding surgical treatment include the significantly decreased bone stock and the incapability of the patients to partially weight bear following surgery. Therefore, special considerations should be performed when dealing with this patient group as surgical treatment is associated with several risks and often accompanied by poor outcomes. This review aims to summarize the current body of knowledge and to give a recommendation concerning a surgical treatment cascade.

Multi-phase volcanic resurfacing at Loki Patera on Io.

The Jovian moon Io hosts the most powerful persistently active volcano in the Solar System, Loki Patera. The interior of this volcanic, caldera-like feature is composed of a warm, dark floor covering 21,500 square kilometres surrounding a much cooler central 'island'. The temperature gradient seen across areas of the patera indicates a systematic resurfacing process, which has been seen to occur typically every one to three years since the 1980s. Analysis of past data has indicated that the resurfacing progressed around the patera in an anti-clockwise direction at a rate of one to two kilometres per day, and that it is caused either by episodic eruptions that emplace voluminous lava flows or by a cyclically overturning lava lake contained within the patera. However, spacecraft and telescope observations have been unable to map the emission from the entire patera floor at sufficient spatial resolution to establish the physical processes at play. Here we report temperature and lava cooling age maps of the entire patera floor at a spatial sampling of about two kilometres, derived from ground-based interferometric imaging of thermal emission from Loki Patera obtained on 8 March 2015 ut as the limb of Europa occulted Io. Our results indicate that Loki Patera is resurfaced by a multi-phase process in which two waves propagate and converge around the central island. The different velocities and start times of the waves indicate a non-uniformity in the lava gas content and/or crust bulk density across the patera.

Subinternship in Radiology - A Practical Start to the Specialization?

Purpose: To identify factors influencing medical students to choose radiology in the four-month clinical elective in the final year of medical school following radiology subinternships. Materials and Methods: A subsample of medical students in a nationwide German online survey evaluated a subinternship in radiology (19 items). They were divided into four groups: Students who could imagine doing a clinical elective in radiology in the practical year based on their experiences during the subinternship ("yes, based on subinternship"), students who could not ("no, based on subinternship") and students who had made this decision prior to the subinternship ("yes, prior to subinternship" and "no, prior to subinternship"). Results: 94 medical students evaluated a radiology subinternship (54.4 % females). Based on their experiences during the subinternship, 54 students (57.4 %) intended to do a final year clinical elective in radiology, 39 of them (41.5 %) being encouraged by the subinternship. 40 (42.6 %) reported having a negative attitude towards a clinical elective in radiology, 16 of them (17.0 %) having made this decision based on their subinternship experience. Groups did not differ regarding gender (p = 0.396) and age (p = 0.853). Students motivated to do a final year clinical elective in radiology experienced excellent academic teaching (p = 0.001) and practical involvement (p = 0.003), achieved their learning goals more often (p = 0.001), were better integrated into the team (p = 0.001), and acquired more practical skills (p = 0.003). Overall satisfaction was higher in these groups (p = 0.001). Conclusion: Satisfaction with a radiology subinternship is crucial for motivating medical students to do a final year clinical elective in radiology. A structured subinternship and continuous mentoring should be targeted to keep students connected to radiology. Key Points: • Radiology subinternships influence further interest in the specialization.• The quality and structure of teaching critically influence student satisfaction.• Team integration and practical involvement positively affect the attitude towards a specialization. Citation Format: • Kasch R, Wirkner J, Hosten N et al. Subinternship in Radiology - A Practical Start to the Specialization? Fortschr Röntgenstr 2016; 188: 1024 - 1030.

Accreting protoplanets in the LkCa 15 transition disk.

Exoplanet detections have revolutionized astronomy, offering new insights into solar system architecture and planet demographics. While nearly 1,900 exoplanets have now been discovered and confirmed, none are still in the process of formation. Transition disks, protoplanetary disks with inner clearings best explained by the influence of accreting planets, are natural laboratories for the study of planet formation. Some transition disks show evidence for the presence of young planets in the form of disk asymmetries or infrared sources detected within their clearings, as in the case of LkCa 15 (refs 8, 9). Attempts to observe directly signatures of accretion onto protoplanets have hitherto proven unsuccessful. Here we report adaptive optics observations of LkCa 15 that probe within the disk clearing. With accurate source positions over multiple epochs spanning 2009-2015, we infer the presence of multiple companions on Keplerian orbits. We directly detect Hα emission from the innermost companion, LkCa 15 b, evincing hot (about 10,000 kelvin) gas falling deep into the potential well of an accreting protoplanet.

Fixation of acetabular fractures via the ilioinguinal versus pararectus approach: a direct comparison.

This study compared the quality of reduction and complication rate when using a standard ilioinguinal approach and the new pararectus approach when treating acetabular fractures surgically. All acetabular fractures that underwent fixation using either approach between February 2005 and September 2014 were retrospectively reviewed and the demographics of the patients, the surgical details and complications were recorded. A total of 100 patients (69 men, 31 women; mean age 57 years, 18 to 93) who were consecutively treated were included for analysis. The quality of reduction was assessed using standardised measurement of the gaps and steps in the articular surface on pre- and post-operative CT-scans. There were no significant differences in the demographics of the patients, the surgical details or the complications between the two approaches. A significantly better reduction of the gap, however, was achieved with the pararectus approach (axial: p = 0.025, coronal: p = 0.013, sagittal: p = 0.001). These data suggest that the pararectus approach is at least equal to, or in the case of reduction of the articular gap, superior to the ilioinguinal approach. This approach allows direct buttressing of the dome of the acetabulum and the quadrilateral plate, which is particularly favourable in geriatric fracture patterns.

Antimicrobial efficacy of preoperative skin antisepsis and clonal relationship to postantiseptic skin-and-wound flora in patients undergoing clean orthopedic surgery.

Nosocomial surgical site infections (SSI) are still important complications in surgery. The underlying mechanisms are not fully understood. The aim of this study was to elucidate the possible role of skin flora surviving preoperative antisepsis as a possible cause of SSI. We conducted a two-phase prospective clinical trial in patients undergoing clean orthopedic surgery at a university trauma center in northern Germany. Quantitative swab samples were taken from pre- and postantiseptic skin and, additionally, from the wound base, wound margin, and the suture of 137 patients. Seventy-four patients during phase I and 63 during phase II were investigated. Microbial growth, species spectrum, and antibiotic susceptibility were analyzed. In phase two, the clonal relationship of strains was additionally analyzed. 18.0 % of the swab samples were positive for bacterial growth in the wound base, 24.5 % in the margin, and 27.3 % in the suture. Only 65.5 % of patients showed a 100 % reduction of the skin flora after antisepsis. The microbial spectrum in all postantiseptic samples was dominated by coagulase-negative staphylococci (CoNS). Clonally related staphylococci were detected in ten patients [nine CoNS, one methicillin-susceptible Staphylococcus aureus (MSSA)]. Six of ten patients were suspected of having transmitted identical clones from skin flora into the wound. Ethanol-based antisepsis results in unexpected high levels of skin flora, which can be transmitted into the wound during surgery causing yet unexplained SSI. Keeping with the concept of zero tolerance, further studies are needed in order to understand the origin of this flora to allow further reduction of SSI.

[Significance and prevention of post-operative wound complications]. / Bedeutung und Prävention postoperativer Wundkomplikationen.

Although surgical site infections (SSI) in dermatologic operative procedures are extremely rare, it is important to understand risks and etiological factors to initiate risk assessment and specific preventive measures. SSI commonly are associated with a complicated, long-term and expensive outcome. Typical wound pathogens of these infections include a variety of multiresistant organisms along with Staphylococcus aureus, Staphylococcus epidermidis, hemolytic streptococci and the gram-negative bacilli Escherichia coli and Pseudomonas aeruginosa. Effective hygienic measures as part of an adequate quality management system should consider the critical points in the development of SSI, particularly in the setting of an outpatient dermatologic unit, such as preparation of the operative area, preoperative skin antisepsis, hand hygiene, safe and skilled technique by surgeons, and barrier nursing to prevent spread of pathogens. The baseline infection incidence in dermatologic surgery inherently is low; nevertheless significant improvements can be achieved by implementation of risk-adapted infection control measures.

[Accidents, illness and injuries involved in road haulage : consequences for medical care and prevention]. / Unfälle, Erkrankungen und Verletzungen im Güterkraftverkehr : Konsequenzen für die medizinische Versorgung und Prävention.

This article reviews basic characteristics of road traffic crashes of heavy vehicles and the current health status of truck drivers. It summarises previous findings from research with a focus on orthopaedic diseases and injuries. These findings comprise a risky health behaviour and high prevalence of associated diseases which can be attributed to both the occupational framework and personal risk-taking behavioural patterns. These are of major importance given the increasing number of drivers and the consequences for acute care and prevention. On the other hand there is a substantial lack of medical care for the drivers on the road. Therefore this article presents the"DocStop Initiative" for medical care on the road, an initiative that runs an international network of care providers (http://www.docstop-online.eu).

[Humeral fracture due to arm wrestling - an indirect fracture in a doped athlete]. / Oberarmschaftfraktur beim Armdrücken - ein indirekter Bruch bei einem gedopten Sportler.

BACKGROUND: Humeral shaft fractures due to recreational arm wrestling are reported from time to time. CASE REPORT: We report the case of a 19 year old, anabolic steroids up taking, recreational arm wrestler who sustained a spiral fracture of the right humeral bone and secondary radial nerve palsy. We discuss the surgical treatment and the biomechanics of this rare injury mechanism. CONCLUSION: Every professional or recreational arm wrestler has to be aware of dangerous sports injuries.

Antiseptic efficacy and tolerance of tissue-tolerable plasma compared with two wound antiseptics on artificially bacterially contaminated eyes from commercially slaughtered pigs.

AIM: To compare the tissue tolerance and efficacy of two wound antiseptics with tissue-tolerable plasma (TTP) on enucleated contaminated eyes from slaughtered pigs in order to draw consequences for the use of TTP on wounds. METHOD: The corneas of extracted eyes were contaminated with Staphylococcus aureus or Pseudomonas aeruginosa. One and 10 min after application of 10% povidone (PVP)-iodine and 0.04% polyhexanide, respectively, the eyes were rinsed with inactivating solution. To test TTP, the plasma pen meandered over the eyes at a speed of 30 mm/s and a distance of 5 mm; the eyes were then rinsed with balanced salt solution. The reduction factor was calculated by the difference between the logarithm of colony-forming units in the rinse before and after antisepsis or TTP application. RESULTS: The efficacy of TTP (reduction factor 2.4-2.9) was significantly higher (p < 0.001) than that of PVP-iodine and polyhexanide (reduction factor 1.7-2.1). CONCLUSION: TTP is more effective than the tested wound antiseptics. The lack of histological damage to the eyes of slaughtered pigs would seem to make its use as a wound antiseptic a viable alternative. In contrast to antiseptics, it supplies additional energy in the form of heat, electric fields and radicals by TTP.

[Thrombosis prophylaxis in trauma surgery units in Germany: a survey]. / Thromboseprophylaxe in unfallchirurgischen Abteilungen in Deutschland : Eine Umfrage.

BACKGROUND: A questionnaire study was conducted to ask trauma surgery centers about thrombosis prophylaxis methods and strategies for the diagnosis and therapy of heparin-induced thrombocytopenia (HIT). METHODS: Questionnaires were sent by post to German hospitals with trauma surgery units inquiring about the use of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH), the duration of medication, and the HIT diagnosis. Questionnaires were evaluated descriptively. RESULTS: 314 of 685 questionnaires sent out were evaluable (46%): half were from general hospitals, 96 (31%) from specialized hospitals, and 53 (17%) from tertiary care hospitals (others: 8). In more than 90%, only LMWH was used. The mean duration of pharmacological thrombosis prophylaxis was 16.6+/-10.4 days (inpatient/outpatient). Only 10% adhered to the recommended platelet count controls every 2 days (days 5-14) for early detection of HIT. CONCLUSIONS: While pharmacological thrombosis prophylaxis following trauma surgery seems to be generally performed according to guidelines, diagnosis and treatment of HIT need to be systematized.

[Two wheels - too dangerous? Analysis of real-world crash data and federal statistics]. / Two wheels - too dangerous? Eine Analyse von Unfalldaten und Bundesstatistik.

BACKGROUND: Motorcyclists profit from improved safety measures and medical care only slightly compared with other road users. The aims of this study were to gain new insights into crash mechanisms and the resulting injuries of motorcyclists and to understand trends in road traffic accident statistics over the last 10 years. METHODS: In our prospective analysis we documented data from collisions in which at least one subject sustained an injury of 2-6 on the Maximum Abbreviated Injury Scale (MAIS). Additionally, key parameters published by the German Federal Statistical Office were analysed. RESULTS: Data were studied for 66 motorcycle crashes and 66 injured subjects. The mean ISS was 17.9, with injuries of the lower limb (44%) and head (41%) being the most frequent in motorcyclists. Psychometric questionnaires revealed that motorcyclists had a significantly higher willingness to take risks compared with drivers of other vehicles. Federal statistics revealed a dramatic increase in mortality in the first months of 2007, but in the next months, mortality decreased to levels comparable to those of the preceding year. CONCLUSIONS: Knowledge of crash mechanisms, injury patterns and profiles of high-risk drivers can help reduce the collision rates and injury severity of motorcyclists.

The value of intraoperative three dimensional fluoroscopy in anterior decompressive surgery of the cervical spine.

PURPOSE: Intraoperative use of the mobile Siremobil Iso-C3D C-arm (Siemens AG, Medical Solutions, Erlangen) considerably improves the information available during cervical spine surgery. We report our experiences with the Iso-C3D fluoroscopic unit during anterior decompressive surgery of the cervical spine. METHODS: We used the mobile Siremobil Iso-C3D C-arm during decompressive cervical spine surgery. The study included 25 patients (22 males, 3 females) with degenerative cervical stenosis. Mean age was 55.9 years (42-73 years). Eighteen patients were surgically treated for one-level, six for two-level and one for three-level disease. Intraoperative 3D imaging was performed to evaluate the extent of bony decompression and to assist correct positioning of the cages when the surgeon believed that sufficient decompression had been achieved. RESULTS: Visualization of the extent of bone removal was good in all patients. In 3 patients, insufficient bony decompression with persisting dorsal osteophytic spurs was noticed on sagittal and axial images. In these patients, surgery had to be continued. Successful decompression was proved thereafter by a second scan. The quality of the images of the cervical spine was sufficient, although slightly inferior to that of a CT scan. CONCLUSION: The Siremobil Iso-C3D provides intraoperative 3D images of bony structures of the cervical spine. Although the imagine quality is inferior to that of a CT, in our series surgical revisions could be avoided in 12.5% of the patients on the basis of these intraoperative images of incomplete bony decompression. This means a reduction of additional costs which would arise with surgical revision.

Not another 4th of July report: uncommon blast injuries to the hand.

OBJECTIVES: Blast injuries to the hand are rare during peacetime and are mainly caused by fireworks. The injury patterns combine a variety of tissue destruction (laceration, dissemination, avulsion, blast, crush and burns). Emergency department staff play a key role in identifying the cause of injury, recognising the full extent of the lesion and referring patients for appropriate treatment. A review was undertaken to examine specificities in emergency department diagnosis and treatment of a separate subgroup of blast injuries. METHODS: The diagnosis and treatment of patients admitted with work-related blast injuries of the hand were retrospectively reviewed. Demographic, clinical and diagnostic data were evaluated and treatment algorithms were analysed. RESULTS: Treatment algorithms of 14 patients suffering blast injuries of the hand due to a vole captive bolt device were analysed. The non-homogeneous injury pattern showed complex multistructural lesions. Relatively innocent-looking superficial wounds mask extensive deep tissue damage, the full extent of which could only be recognised after rigorous surgical exploration. All patients but one were treated by immediate surgery, debridement of tissue necrosis and lavage. A delay before surgery resulted in phlegmonous infection in one case. CONCLUSION: Emergency staff must be aware of the potential dangers of this subgroup of blast injuries and the worsening effect of delay before surgery. Only knowledge of the underlying mechanism of the accident enables the emergency physician to understand the complexity and full extent of the injury pattern and to refer patients early for appropriate surgical management. Conservative treatment is inappropriate, dangerous and may become a focus of negligence claims.

Harm set, harm get: hand injuries caused by vole captive bolt devices.

INTRODUCTION: Vole captive bolt devices are special mouse traps which belong to the spring guns. Devices and ammunition are available over the counter, age of consent (18 years) is the only legal restriction. Loaded with a 700 J cartridge the device is positioned in the vole passage. By slightly touching a metal ring in front of the muzzle the mouse triggers the shoot and is killed by a high-pressure gas jet. In spite of the high-potential danger causing injuries no study on accidents due to blank cartridge mouse shooters has been published yet. METHODS: Patients suffering hand injuries due to vole captive bolt devices were identified. Both type and severity of injury and treatment were recorded. An assessment instrument was designed to identify the critical circumstances leading to injury. Also safety regulations and security measures were examined. RESULTS: Between August 2004 and February 2007 20 male patients (average age 48.65 years) suffered accidental hand injuries due to vole captive bolt devices. Patterns of injury reached from cutaneous burning up to traumatic amputation of fingers and separation of the whole hand. In 9 of 20 cases an unintended shoot was triggered in secured status of the devices so the accidents were caused by failure of the security mechanism. Ballistic considerations, casualties and the injury pattern itself differ from well-studied hand injuries caused by blank cartridges or fireworks. CONCLUSION: The study presents a previously unpublished injury pattern due to vole captive bolt devices. Forensic approach has to keep in mind this previously unknown mechanism as cause of accident or self-mutilation.

Oldie but goldie: Bristow-Latarjet procedure for anterior shoulder instability.

PURPOSE: To analyse the functional and radiological outcomes of the Bristow-Latarjet procedure in patients with recurrent anterior glenohumeral instability. METHODS: Records of 29 patients were reviewed retrospectively. Date of first dislocation, injury mechanism, and number of recurring dislocations before and after surgery were recorded. The overall function and stability of the shoulder was evaluated. RESULTS: 24 (83%) of the glenohumeral instabilities were caused by trauma. The mean number of recurring dislocations was 8 (95% confidence interval [CI], 0-18); one patient had had 40 recurrences. No dislocation ensued postoperatively. The overall functional outcome was good, with a mean Rowe score of 90 points (95% CI, 78-100). Scores of 17 (59%) of the patients were excellent, 7 (24%) were good, 3 (10%) were fair, and 2 (7%) were poor. CONCLUSION: The Bristow-Latarjet procedure is a good surgical treatment for recurrent anterior-inferior instability of the glenohumeral joint.

[Retrospective analysis of march fractures in the german armed forces in the years 1998 to 2000]. / Retrospektive Untersuchung von Marschfrakturen bei der Bundeswehr in den Jahren 1998 bis 2000.

AIM: The aim of this study was to determine the incidence/frequency of march fractures in the German Armed Forces in the years from 1998 to 2000. In particular, the age, length of service, distribution of the metatarsals and the occurrence of anthropometric risk factors were considered. METHODS: At the Medicostatistical Institute of the German Armed Forces the records of soldiers, 191 cases with 204 fractures, with diagnosed "march fractures" were selected and analyzed. RESULTS: 82% of the affected soldiers were between 19 and 22 years old. More than 50% of the fractures occurred within the first eight weeks of service. In about 64% the 3rd metatarsal was affected, in 25% the 2nd metatarsal and in only 11% of all cases the 4th, 5th, and 1st metatarsals. Soldiers were exempted from duty for an average of 26.5 days. No specific anthropometric risk factors were found to be connected with the occurrence of march fractures. CONCLUSION: March fractures in the German Armed Forces are non-predictable injuries of young and physically fit individuals; youth is not a protective factor. There is an increased risk for march fractures during the first weeks of military service. There appears to be no possibility for a screening.