The aim of the study was to compare device life of more recent indwelling voice prostheses Provox Vega and Blom-Singer Dual Valve to device life of well-known standard devices (Provox 2, Blom-Singer Classic). In a prospective, non-randomised study, device life of Blom-Singer Classic, Blom-Singer Dual Valve, Provox2, Provox Vega and Provox ActiValve voice prostheses was recorded in a group of 102 laryngectomised patients. In total 749 voice prosthesis were included. Average overall life time was 108 days, median 74 days. The prosthesis with the longest dwell time was the Provox ActiValve (median 291 days). Provox Vega had longer device life compared with Provox2 (median 92 days vs 66 days; p = 0.006) and compared with Blom-Singer Classic (median 92 days vs 69 days; p = 0.004). In conclusion, device lifetimes of Provox Vega and ActiValve were better than those of Provox2 and the Blom-Singer Classic. New voice prostheses, with a defined valve opening pressure (Provox Vega, Provox ActiValve, Blom-Singer Dual Valve) had longer lifetimes than prostheses without a defined opening pressure (Blom-Singer Classic and Provox 2).

One-stage extrafocal posterior stabilisation combined with anterior debridement and anterior column reconstruction with bone grafts or titanium cages is a safe and effective strategy for patients with vertebral osteomyelitis in need of surgery. Titanium cages have proven to be biomechanically advantageous, especially in cases of extensive destruction and are not associated with higher rates of persistence or recurrence of infection compared to autologous bone grafts.

No abstract

The velocity of nanoparticle agglomerates and 1 μm latex spheres approaching an impaction surface from a free gas jet was measured by LDA at pressures of 7.4 and 1.8 kPa, respectively. The "aerodynamically transparent" carbon nano-agglomerates gave sufficient LDA signal while the drag force was dominated by the size of the individual primary particles (diameter about 11 nm). The particle velocity as a function of distance from the impaction plate was also modelled on the basis of a CFD simulation of the flow field and subsequent numerical integration of the equation of motion with the slip correction factor as an adjustable parameter.For a pressure of 7.4 kPa the measured and calculated velocities agreed very well, when using the Stokes formula with classical parameters for the slip correction. Surprisingly however, at 1.8 kPa the effective drag on the nanoparticles was lower than predicted by a factor of 17 and on the 1 μm latex sphere by a factor of 6, respectively. The physical reason for this reduction of the drag is not known so far. The predicted particle impact velocity at 1.8 kPa was 54% of the maximum gas velocity. This factor is much lower than the often used factor of 0.85 derived by Marple.

No abstract