The "dermal cage": a modification of the inferior pedicle breast reduction

In spite of more recent techniques for breast reduction, the inferior pedicle technique has proven to be enduring and still a very popular option in the plastic surgeon's armamentarium despite certain shortcomings. This technique is especially important for treating large breasts with a long sternal notch-to-nipple distance. The modifications we describe in this article overcome some of the main drawbacks of the standard inferior pedicle technique and make the procedure particularly effective when used on appropriately selected patients. This is achieved principally by the creation of a strong, durable, and internalized "dermal cage" that remains fixed to the chest wall in the upper part, as well as on both sides, to support the majority of the remaining breast tissue. This serves several purposes, including narrowing the breast thereby giving good projection and reduction of the N-IMF length of the inferior pedicle. Through suspension and fixation of the inferior pedicle to the chest wall, one can mitigate the effects of gravity on the inferior pedicle. The benefits of this include reduced tension on the T junction, thereby reducing the incidence of wound dehiscence in the immediate postoperative period, while reduction of tension on the nipple-areola complex reduces "bottoming" out over the long term. This process has been the main shortcoming of the inferior pedicle technique to date. The technique was used on 26 patients over a 7-year period with a mean long-term follow-up of 41 months. The results demonstrate the short- and long-term effectiveness of our own particular combination of modifications to previously described techniques and modifications of the inferior pedicle breast reduction. ----- LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266

Spider silk fibres in artificial nerve constructs promote peripheral nerve regeneration

OBJECTIVE: In our study, we describe the use of spider silk fibres as a new material in nerve tissue engineering, in a 20-mm sciatic nerve defect in rats. MATERIALS AND METHODS: We compared isogenic nerve grafts to vein grafts with spider silk fibres, either alone or supplemented with Schwann cells, or Schwann cells and matrigel. Controls, consisting of veins and matrigel, were transplanted. After 6 months, regeneration was evaluated for clinical outcome, as well as for histological and morphometrical performance. RESULTS: Nerve regeneration was achieved with isogenic nerve grafts as well as with all constructs, but not in the control group. Effective regeneration by isogenic nerve grafts and grafts containing spider silk was corroborated by diminished degeneration of the gastrocnemius muscle and by good histological evaluation results. Nerves stained for S-100 and neurofilament indicated existence of Schwann cells and axonal re-growth. Axons were aligned regularly and had a healthy appearance on ultrastructural examination. Interestingly, in contrast to recently published studies, we found that bridging an extensive gap by cell-free constructs based on vein and spider silk was highly effective in nerve regeneration. CONCLUSION: We conclude that spider silk is a viable guiding material for Schwann cell migration and proliferation as well as for axonal re-growth in a long-distance model for peripheral nerve regeneration

A simple analytical method for residual stress measurement on suspended MEM structures using surface profilometry

This paper presents an analytical method to calculate residual stress and Young’s modulus in clamped-clamped beams. These types of structures are a typical building block of many MEMS devices, and this guarantees an accurate transferability of the measured parameters. The method is based on the determination of beam bending as a function of applied load by means of a surface profiler, and as a function of beam length. By modeling analytically both the elastic and the stress contribution to beam bending, it is possible to obtain both the stress value and the Young’s modulus by a simple fitting of the experimental data. Results are presented for electrodeposited gold beam arrays of different width, but the method is in principle exploitable for every type of suspended film where the residual stress strongly influences the material properties. Accuracy and limitations of the method are also discussed

Limitations of nerve repair of segmental defects using acellular conduits

The authors present the case of a 20-year-old man who, 3 months after his initial injury, underwent repair of a 1.7-cm defect of the ulnar nerve at the wrist; repair was performed with an acellular nerve allograft. Given the absence of clinical or electrophysiological recovery at 8 months postrepair, the patient underwent reexploration, excision of the "regenerated cable," and rerepair of the ulnar nerve with sural nerve autografts. Histology of the cable demonstrated minimal axonal regeneration at the midpoint of the repair. At the 6- and 12-month follow-ups of the sural nerve graft repair, clinical and electrophysiological evidence of both sensory and motor reinnervation of the ulnar nerve and associated hand muscles was demonstrated. In this report, the authors describe a single case of failed acellular nerve allograft and correlate the results with basic science and human studies reporting length and diameter limitations in human nerve repair utilizing grafts or conduits devoid of viable Schwann cells