In vivo skin characterization methods were shown to be useful in the detection of microstructural alterations of the dermis due to skin diseases. Specifically, the diagnostic potential of skin suction has been widely explored, yet measurement uncertainties prevented so far its application in clinical assessment. In this work, we analyze specific factors influencing the reliability of suction measurements. We recently proposed a novel suction device, called Nimble, addressing the limitations of existing instruments, and applied it in clinical trials quantifying mechanical differences between healthy skin and scars. Measurements were performed with the commercial device Cutometer and with the new device. A set of new suction measurements was carried out on scar tissue and healthy skin, and FE-based inverse analysis was applied to determine corresponding parameters of a hyperelastic-viscoelastic material model. FE simulations were used to rationalize differences between suction protocols and to analyze specific factors influencing the measurement procedure. Tissue stiffness obtained from Cutometer measurements was significantly higher compared to the one from Nimble measurements, which was shown to be associated with the higher deformation levels in the Cutometer and the nonlinear mechanical response of skin. The effect of the contact force exerted on skin during suction measurements was quantified, along with an analysis of the effectiveness of a corresponding correction procedure. Parametric studies demonstrated the inherently higher sensitivity of displacement- over load-controlled suction measurements, thus rationalizing the superior ability of the Nimble to distinguish between tissues.

Background: Extended avulsion injuries are associated with significant loss of skin and subcutaneous fat, leaving the reconstructive surgeon with the challenge of substituting all tissues lost in the best possible way. We wanted to test whether the combined use of a Vacuum Assisted Closure system (VAC) and Integra Dermal Regeneration Template (IDRT) matched the required treatment profile encompassing initial control of infection, remodeling of body contours, and reconstruction of near normal skin. Materials and Methods: 4 children with massive lower extremity avulsion injuries were treated with early necrosectomy, VAC application for 3–5 weeks for wound cleansing and wound bed conditioning, subsequent implantation of IDRT, and finally autologous split thickness skin grafting (STSG) for definitive wound closure. Thereafter, a standard rehabilitation program was used. The key parameters of VAC and IDRT application, take rates of IDRT and STSG, complications, length of stay, and final outcome were recorded. Results: In all patients, early removal of necrosis and infection control was successfully achieved. Continuous VAC application fostered the formation of a several millimeters thick new tissue layer partly compensating for the lost hypodermis. IDRT implantation and subsequent STSG yielded take rates of nearly 100% and both functionally and cosmetically excellent long-term results. There were no major complications. Conclusion: The combination of VAC and IDRT in children with massive leg avulsion injuries is feasible, safe, and delivers high-quality long-term outcomes that appear to justify the multiple operative procedures, the long hospitalization times, and the comparatively high costs entailed.

Background: Self-filling, hydrogel-based osmotic tissue expanders have been successfully used for several years, mainly in adult patients. We wanted to test this novel device in pediatric plastic and reconstructive surgery. Material and Methods: Between November 2004 and September 2009, we implanted 53 osmotic tissue expanders following standard surgical principles in a total of 30 children and adolescents with burn scars, congenital nevi, alopecia, or foot deformities. Results: All expanders reached their predicted volume within 6 weeks and 51 (96.2%) produced a sufficient amount of additional skin for the intended coverage of the defect. A serious infection precluding the planned reconstructive procedure occurred with 2 expanders (3.8%). Minor complications occurred at 6 implantation sites (11.4%), and consisted of small necrotic areas and perforations (n=3) and minor infections (n=3). These problems could be controlled and did not interfere with the subsequent plasty. The final results recorded at the last follow-up (mean: 21 months, range: 9–48 months) were rated as excellent in 25, good in 19, moderate in 6, and poor in 1 patient. Conclusion: This is apparently the largest pediatric series in which self-filling expanders have been used. The data obtained indicates that self-filling expanders can be safely and effectively used for various plastic, reconstructive and orthopedic procedures in children and adolescents. The fact that numerous painful and distressing filling sessions are obviated with these expanders is particularly beneficial for those children too young to understand and cooperate. Moreover, this approach minimizes the risk of infection and lowers costs.