[Operative treatment of pediatric open fractures of the lower limb using the Taylor spatial frame fixator]

The operative management of open fractures of the lower limb requires a consistent treatment to avoid soft tissue complications. Acute angular shortening of the fracture enabling primary soft tissue closure is still an uncommon operative technique because of difficulties in correcting the secondary deformity. The case of a pediatric open fracture of the lower limb (Gustilo type IIIa) is described, which was treated with acute angular shortening followed by gradual correction using the Taylor spatial frame (TSF).

Measurement of common carotid artery intima-media thickness in clinical practice: comparison of B-mode and RF-based technique

PURPOSE

The common carotid artery intima-media thickness (CCA-IMT) is usually measured using B-mode ultrasound images. A different approach for CCA-IMT detection is based on radio frequency (RF) multiple M-line analysis.

MATERIALS AND METHODS

The present study explores the relationship between B-mode and RF measurement of CCA-IMT, as well as the reproducibility of both methods in 136 patients recently diagnosed with cardiovascular disease. Within one session, repeated measurements were made in the distal CCA bilaterally, using the B-mode (averaged over 10 mm) and RF technique (averaging 12 M-lines over 14 mm).

RESULTS

The two methods correlate well (Pearson r = 0.765). The CCA-IMT values measured with B-mode and RF were 0.779 +/- 0.196 mm and 0.734 +/- 0.172 mm, respectively. B-mode CCA-IMT is significantly larger than RF CCA-IMT (mean difference of 0.045 mm, SEM 7.8 microm; t = 5.82; p < 0.001). In the multivariate regression analysis, carotid artery stenosis, inhomogeneous IMT and diabetes mellitus were the main predictors of differences between B-mode and RF CCA-IMT. The intrapatient variation for B-mode and RF-based CCA-IMT is comparable (0.05 +/- 0.04 mm and 0.07 +/- 0.05 mm, respectively).

CONCLUSION

CCA-IMT values measured with RF and B-mode have similar reproducibility and exhibit acceptable correlation, but RF CCA-IMT is significantly smaller. The difference between both methods is mainly due to advanced atherosclerosis. Hence, both methods can be used reliably to measure CCA-IMT in clinical practice.

Development, Control, and Evaluation of an Actuated Car Door

Actuated car doors are a promising way to increase the convenience of access to cars. We propose an advanced actuation and control concept which can easily be integrated into conventional car doors. By utilizing a linear, nonbackdrivable actuator and various sensors, both automatic and manual door operations are enabled. A discrete state controller ensures a safe operation of the door, including automatic opening and closing. The realization of a supportive, high-quality haptic interaction with the car door for the manual operation is the principal part of our work. Due to the impracticality of a direct measurement of the user interaction force at a car door, we chose impedance control to render the desired dynamics. The impedance was designed to provide a convenient, intuitive, and safe manual handling of the door. We implemented and tested four different impedance control schemes, of which impedance control with actuator force feedback performed best. Two experimental evaluations with 16 and 27 participants revealed a predominant approval of the actuated car door.

[Risk assessment of sex offenders in a German-speaking sample. Applicability of PCL-SV, HCR-20+3, and SVR-20]

Regarding the relatively high relapse rates of sex offenders, an increasing need for forensic prognosis reports, doubts about their validity, and a continued lack of qualified forensic experts makes the supposedly simple application of instruments such as the Psychopathy Check List Screening Version (PCL-SV), HCR-20+3, or the Sexual Violence Risk 20 (SVR-20) very tempting. Those tools supply numeric values for quantifying assumed risk and have begun appearing more frequently in forensic reports. Their use for specific collectives without prior examination of accuracy, admissibility, and accountability may lead to serious mistakes and risks. This study by the Forensic Department of the Psychiatric University Hospital in Basel, Switzerland, is part of a larger cohort study on forensic risk assessment. It investigates among others the differential indication for PCL-SV, HCR-20+3, and SVR-20. In the present study, 64 sex offenders were retrospectively rated with these three instruments based on their respective reports for prior risk assessment, including criminal reports. Those ratings were then compared with prior results from the Structured Risk Assessment of Basel, as performed by the experts. Results of this study confirm the utility of PCL-SV, HCR-20+3 and SVR-20 in a German-speaking sample of sex offenders primarily as a scientific instrument. Beyond that, these instruments may also be used literally as a checklist. Their use for risk quantification should be limited primarily to the subgroup of antisocial and physically aggressive sex offenders.

[The Taylor Spatial Frame. Correction of posttraumatic deformities of the tibia and hindfoot]

INTRODUCTION

Posttraumatic deformities in the lower limb are mainly multidirectional, with angulation, translation, and rotatory deformities. Acute corrections with internal fixation are often not possible due to the soft tissue damage and the extent of the deformity. The Taylor Spatial Frame (TSF) allows correction in a virtual hinge with 6 axes, thus enabling the correction of multidirectional deformities simultaneously.

METHODS

From February 2003 until December 2006, we applied 31 TSFs to 20 patients with a posttraumatic deformity of the tibia and hindfoot. The mean patient age was 41 years (range 12-73). 9 patients had a nonunion of the tibia with deformity, 6 had a malunion of the lower tibia and ankle, 3 had an angular deformity after ankle fusion, and 2 had malaligned Ilizarov bone segment transports. The mean follow-up time was 25.3 months (range 10-82).

RESULTS

In all 20 patients, full correction of the deformity was achieved. The mean time for correction was 29 days (range 5-82). On average, the frame was worn (time to healing) 164.2 days (80-300) and the mean distraction rate was 1.1 mm/day (0.5-2.0). The Web-based planning was done two times per case for full deformity correction. Complications were 3 pin-site infections, 2 insufficient callus formations and 1 pinhole stress fracture.

CONCLUSIONS

The main advantage of the TSF compared with other external frames is the ability to perform simultaneous correction of angular, axial, translational, and rotatory deformities. This enables a reduced correction time and increased patient comfort.

[The Taylor spatial frame fixator. Soft-tissue distraction for post-traumatic varus deformities of the hindfoot]

Despite adequate primary treatment many ankle fractures result in post-traumatic deformities and arthrosis. Revision mostly requires a multidirectional correction whereas internal fixation procedures are often not applicable due to soft tissue damage and the extent of deformity. The Taylor spatial frame enables simultaneous correction of multidirectional deformities through a virtual hinge using the same ideas of distraction osteogenesis as the Ilizarov fixator. The presented case demonstrates minimally invasive correction of a complex deformity of the ankle with the Taylor spatial frame fixator. Orthogonal alignment was achieved and a stabilizing tibiotalar arthrodesis was performed achieving a good functional and pain-free result.

Distribution of cadmium among geochemical fractions in floodplain soils of progressing development

Initial soil development in river floodplains influences soil properties and processes. In this study, suites of young floodplain soils sampled at three European rivers (Danube/Austria, Ebro/Spain and Elbe/Germany) were used to link soil development to the soils' retention capacity for cadmium. Geochemical fractionation of original and metal-spiked soils was conducted. Cadmium remained in weakly bound fractions in both original and spiked soils, representing an entirely different behaviour than observed for copper in an earlier study. The tendency of incorporation into more stable forms over time was only slightly expressed. Correlation analysis revealed the involvement of different sorption surfaces in soil, with no single soil constituent determining cadmium retention behaviour. Nevertheless, in the calcareous soils of the Danube floodplain, we found increased cadmium retention and decreased portions of desorbable cadmium with progressing soil development.

[Operative management and fracture care of the lower leg with the Ilizarov fixator in morbidly obese patients: literature review and results]

Given the rising prevalence of obesity, surgeons and hospitals must become more familiar with the treatment and operative management of obese patients. Several additional pre- and postoperative considerations must be involved such as appropriate assessment of comorbidities and requirements for special equipment. There are still very few data regarding morbidly obese patients with BMIs >50 kg/m(2). After a general literature review of operative management of obese patients, we report on fracture care of the lower limb in such patients with custom-made Ilizarov ring fixators. We found them suited to bear enormous weight-loading but that associated comborbidities can limit successful fracture care.

Stark spectroscopy of excited-state transitions in a conjugated polymer

Stark spectroscopy, which is well established for probing transitions between the ground and excited states of many material classes, is extended to transitions between transient excited states. To this end, it is combined with femtosecond pump-probe spectroscopy on a conjugated polymer with appropriately introduced traps which harvest excitation energy and build up a sufficient excited state population. The results indicate a significant difference in the effective dipole moments between two short lived excited states.