Outcome of rectus femoris muscle flaps for groin coverage after vascular surgery.

OBJECTIVE: The aim of this retrospective cohort study was to investigate the outcome of rectus femoris muscle flaps (RFFs) for deep groin wound complications in vascular surgery patients and to compare the outcome with a cohort of sartorius muscle flaps (SMFs) because the RFF is a promising alternative technique for groin coverage. METHODS: All RFFs and SMFs performed by vascular surgeons in a regional collaboration in The Southern Netherlands were retrospectively reviewed. Primary outcomes were muscle flap survival, overall and secondary graft salvage, and limb salvage. Secondary outcomes were 30-day groin wound complications and mortality, donor site and vascular complications, 1-year amputation-free survival, overall patient survival, impaired knee extensor function, and length of hospital stay. RESULTS: A total of 96 RFFs were performed in 88 patients (mean age, 68 years; 67% male) and compared with a cohort of 30 SMFs in 28 patients (mean age, 64 years; 77% male). At a mean follow-up of 29 months and 23 months, respectively, comparable flap survival (94% vs 90%), secondary graft salvage (80% vs 92%), and limb salvage (89% vs 90%) rates were found. The 30-day mortality rates were 12% and 17%, respectively, and the 1-year amputation-free survival was comparable between treatment groups (71% vs 68%). CONCLUSIONS: This study presents a large series of RFFs for deep groin wound complications after vascular surgery. We demonstrate that muscle flap coverage using the rectus femoris muscle by vascular surgeons is an effective way to manage complex groin wound infections in a challenging group of patients, achieving similarly good results as the SMF.

A systematic review on the use of muscle flaps for deep groin infection following vascular surgery.

OBJECTIVE: The aim of this systematic review is to assess potential differences in effectiveness (graft loss and limb loss) between the sartorius muscle flap (SMF) and the rectus femoris muscle flap (RFF) coverage technique for deep groin wound infection following vascular surgery. Our hypothesis was that RFF reconstruction is more effective in groin coverage. METHODS: The PubMed, Embase, and Medline databases were systematically searched by two independent researchers for articles reporting effectiveness of both muscle flaps in the treatment of groin infections following vascular surgery. After quality assessment using the Newcastle-Ottawa Scale and Methodological Index for NOn-Randomized studies (MINOR) scores and data extraction, individual results of the included studies were reviewed. Weighted pooled outcome estimates were calculated. RESULTS: A total of 17 studies comprising 544 SMF reconstructions and 238 RFF reconstructions were included. The pooled flap survival rate was 100% in both groups, with a pooled amputation rate of 0% and 2%, respectively. In the RFF group, a pooled 30-day mortality rate of 0% was found, compared with 1% in the SMF group. Pooled graft loss rates were 2% in the RFF group and 21% in the SMF group. Only one head-to-head comparison between both muscle flaps was performed, finding no significant differences. CONCLUSIONS: Deep groin infection after vascular surgery can be treated with debridement and local muscle flap coverage. In this systematic review, superiority of either muscle flap on amputation or mortality rates was not demonstrated; however, there was a lower rate of vascular graft loss after RFF reconstruction. These conclusions are based on low-quality evidence because of limited data. Local muscle flap reconstruction using both techniques is effective in the treatment of infected groin wounds, achieving good results in a fragile group of patients. Therefore, anatomical and patient characteristics, which were not assessed in this analysis, are critical in the decision-making process on which muscle flap reconstruction is the best treatment option for an individual patient.

Nanoplasma Formation by High Intensity Hard X-rays.

Using electron spectroscopy, we have investigated nanoplasma formation from noble gas clusters exposed to high-intensity hard-x-ray pulses at ~5 keV. Our experiment was carried out at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility in Japan. Dedicated theoretical simulations were performed with the molecular dynamics tool XMDYN. We found that in this unprecedented wavelength regime nanoplasma formation is a highly indirect process. In the argon clusters investigated, nanoplasma is mainly formed through secondary electron cascading initiated by slow Auger electrons. Energy is distributed within the sample entirely through Auger processes and secondary electron cascading following photoabsorption, as in the hard x-ray regime there is no direct energy transfer from the field to the plasma. This plasma formation mechanism is specific to the hard-x-ray regime and may, thus, also be important for XFEL-based molecular imaging studies. In xenon clusters, photo- and Auger electrons contribute more significantly to the nanoplasma formation. Good agreement between experiment and simulations validates our modelling approach. This has wide-ranging implications for our ability to quantitatively predict the behavior of complex molecular systems irradiated by high-intensity hard x-rays.

Emerging photon technologies for probing ultrafast molecular dynamics.

The understanding of physical and chemical changes at an atomic spatial scale and on the time scale of atomic motion is essential for a broad range of scientific fields. A new class of femtosecond, intense, short wavelength lasers, the free electron lasers, has opened up new opportunities to investigate dynamics in many areas of science. For chemical dynamics to advance however, a rigorous, quantitative understanding of dynamical effects due to intense X-ray exposure is also required. We illustrate this point by reporting here an experimental and theoretical investigation of the interaction of C(60) molecules with intense X-ray pulses, in the multiphoton regime. We also describe the potential of new available instrumentation and explore their potential impact in physical, chemical and biological sciences when they are coupled with emerging photon technologies.

Femtosecond X-ray-induced explosion of C60 at extreme intensity.

Understanding molecular femtosecond dynamics under intense X-ray exposure is critical to progress in biomolecular imaging and matter under extreme conditions. Imaging viruses and proteins at an atomic spatial scale and on the time scale of atomic motion requires rigorous, quantitative understanding of dynamical effects of intense X-ray exposure. Here we present an experimental and theoretical study of C60 molecules interacting with intense X-ray pulses from a free-electron laser, revealing the influence of processes not previously reported. Our work illustrates the successful use of classical mechanics to describe all moving particles in C60, an approach that scales well to larger systems, for example, biomolecules. Comparisons of the model with experimental data on C60 ion fragmentation show excellent agreement under a variety of laser conditions. The results indicate that this modelling is applicable for X-ray interactions with any extended system, even at higher X-ray dose rates expected with future light sources.

Analytical density functional theory of homogeneous vapor condensation

Starting from an exact gradient transcription of the perturbative density functional theory of homogeneous vapor condensation, we propose an analytical approximation that reproduces the density profile and free energy of critical fluctuations to high accuracy. For a broad variety of substances, including nonpolar, weakly polar, and metallic liquids, the method predicts nucleation rates that are orders of magnitude closer to experiment than those from the classical approach. The present treatment incorporates detailed molecular theory into macroscopic modeling.