Background and Objective: We have developed a lightactivated method called photochemical tissue bonding (PTB) for closing wounds using green light and a photosensitizing dye (Rose Bengal-RB) to initiate photochemical crosslinking of wound surface proteins. These studies were designed to determine whether RB causes phototoxicity during closure of skin incisions with PTB. Study Design/Materials and Methods: RB phototoxicity was evaluated after sealing incisions in porcine skin ex vivo and rabbit skin in vivo using PTB (1 mM RB, 100 J/cm 2 , 532 nm, 0.3 or 0.5 W/cm 2 .) Dead cells were identified by pyknotic nuclei and eosinophilic cytoplasm on H&E-stained sections. The influence on RB phototoxicity of penetration of RB into the wound wall (by confocal microscopy), RB concentration in the tissue (by extraction), and fluence of 532 nm reaching depths in skin (calculated from skin optical properties) were investigated. Results: No significant differences were found in the percent dead cells in PTB-treated and control incisions in porcine skin at 24 hours or in rabbit skin at 2 hours and 3 and 7 days after surgery. RB was retained in a $100 mm wide band next to the wound wall. The mean RB concentration within this band was 0.42 AE 0.03 mM. Monte Carlo modeling of light distribution indicated that the fluence rate decreased from the subsurface peak to 0.5 W/ cm 2 in the mid-dermis ($350 mm.) In vitro RB phototoxicity to dermal fibroblasts yielded an LD 50 of 0.50 AE 0.09 J/cm 2 when the cells contained 0.46 mM RB. Conclusions: PTB does not cause phototoxicity when used to repair skin wounds even though the RB concentration and 532 nm fluence in the mid-dermis during PTB are much greater than the LD 50 for RB phototoxicity in vitro. These results indicate that phototoxicity is not a concern when using PTB for tissue repair.

Nerves of the peripheral nervous system have, to some extent, the ability to regenerate after injury, particularly in instances of crush or contusion injuries. After a controlled crush injury of the rat sciatic nerve, demyelination and remyelination are followed with functional assessments and imaged both ex vivo and in vivo over the course of 4 weeks with video-rate coherent anti-Stokes Raman scattering (CARS) microscopy. A new procedure compatible with live animal imaging is developed for performing histomorphometry of myelinated axons. This allows quantification of demyelination proximal and remyelination distal to the crush site ex vivo and in vivo respectively.

A novel molecular suturing technique produces effective wound sealing and less scarring than closure with nylon interrupted epidermal sutures. Comparisons with better suturing techniques are warranted.

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Abstract. We present spectral domain polarization-sensitive optical coherence tomography (SD PS-OCT) imaging of peripheral nerves. Structural and polarization-sensitive OCT imaging of uninjured rat sciatic nerves was evaluated both qualitatively and quantitatively. OCT and its functional extension, PS-OCT, were used to image sciatic nerve structure with clear delineation of the nerve boundaries to muscle and adipose tissues. A long-known optical effect, bands of Fontana, was also observed. Postprocessing analysis of these images provided significant quantitative information, such as epineurium thickness, estimates of extinction coefficient and birefringence of nerve and muscle tissue, frequency of bands of Fontana at different stretch levels of nerve, and change in average birefringence of nerve under stretched condition. We demonstrate that PS-OCT combined with regular-intensity OCT (compared with OCT alone) allows for a clearer determination of the inner and outer boundaries of the epineurium and distinction of nerve and muscle based on their birefringence pattern. PS-OCT measurements on normal nerves show that the technique is promising for studies on peripheral nerve injury.

The authors conclude that coherent anti-Stokes Raman scattering microscopy has the ability to image the peripheral nerve following demyelinating crush injury. This technology, which permits in vivo, real-time microscopy of nerves at a resolution of 5 mum, could provide invaluable diagnostic and prognostic information regarding intraneural preservation and recovery following injury.

Human bite wounds present a challenge to any emergency department, given the many issues involved in their management. Underestimation of the complexity and potential sequelae of these wounds will result in a suboptimal outcome for the patient.

BackgroundThe aim of this study was to review the recipient vessels used in our cases of facial reanimation with free functional muscle transfer and to identify patient variables that may predict when the facial vessels are absent. From this we present a protocol for vessel selection in cases when the facial artery and/or vein are absent.MethodsPatients were identified from November 2006 to October 2013. Data was collected on patient demographics, facial palsy aetiology, history of previous facial surgery/trauma and flap/recipient vessels used. A standard operative approach was adopted and performed by a single surgeon.ResultsEighty-seven eligible patients were identified for inclusion amongst which 98 hemifaces were operated upon. The facial artery and vein were the most commonly used recipient vessels (90% and 83% of patients, respectively). Commonly used alternative vessels were the transverse facial vein and superficial temporal artery. Those with congenital facial palsy were significantly more likely to lack a suitable facial vein (P=0.03) and those with a history of previous facial surgery or trauma were significantly more likely to have an absent facial artery and vein (P<0.05).ConclusionsOur algorithm can help to guide vessel selection cases of facial reanimation with free functional muscle transfer. Amongst patients with congenital facial palsy or in those with a previous history of facial surgery or trauma, the facial vessels are more likely to be absent and so the surgeon should then look towards the transverse facial vein and superficial temporal artery as alternative recipient structures.