[Influence of chronic, structural changes of the muscle-tendon unit on the indication and technique of rotator cuff reconstruction]

Rotator cuff lesions are common and the incidence increases with age. After tendon rupture of the rotator cuff, the muscle-tendon unit retracts, which is accompanied by muscle fatty infiltration, atrophy, and interstitial fibrosis of the musculature, thus, fundamentally changing the muscle architecture. These changes are important prognostic factors for the operative rotator cuff reconstruction outcome. Selection of the correct time point for reconstruction as well as the optimal mechanical fixation technique are decisive for successful attachment at the tendon-to-bone insertion site. Thus, knowledge of the pathophysiological processes plays an important role. The goal of this article is to establish a relationship between currently existing evidence with respect to the preoperatively existing changes of the muscle-tendon unit and the choice of the time for the operation and the operative technique.

Validation of a statistical shape model-based 2D/3D reconstruction method for determination of cup orientation after THA

The aim of this study was to validate the accuracy and reproducibility of a statistical shape model-based 2D/3D reconstruction method for determining cup orientation after total hip arthroplasty. With a statistical shape model, this method allows reconstructing a patient-specific 3D-model of the pelvis from a standard AP X-ray radiograph. Cup orientation (inclination and anteversion) is then calculated with respect to the anterior pelvic plane that is derived from the reconstructed model.

Intraoperative template-molded bone flap reconstruction for patient-specific cranioplasty

Cranioplasty is a common neurosurgical procedure. Free-hand molding of polymethyl methacrylate (PMMA) cement into complex three-dimensional shapes is often time-consuming and may result in disappointing cosmetic outcomes. Computer-assisted patient-specific implants address these disadvantages but are associated with long production times and high costs. In this study, we evaluated the clinical, radiological, and cosmetic outcomes of a time-saving and inexpensive intraoperative method to mold custom-made implants for immediate single-stage or delayed cranioplasty. Data were collected from patients in whom cranioplasty became necessary after removal of bone flaps affected by intracranial infection, tumor invasion, or trauma. A PMMA replica was cast between a negative form of the patient's own bone flap and the original bone flap with exactly the same shape, thickness, and dimensions. Clinical and radiological follow-up was performed 2 months post-surgery. Patient satisfaction (Odom criteria) and cosmesis (visual analogue scale for cosmesis) were evaluated 1 to 3 years after cranioplasty. Twenty-seven patients underwent intraoperative template-molded patient-specific cranioplasty with PMMA. The indications for cranioplasty included bone flap infection (56%, n = 15), calvarian tumor resection (37%, n = 10), and defect after trauma (7%, n = 2). The mean duration of the molding procedure was 19 ± 7 min. Excellent radiological implant alignment was achieved in 94% of the cases. All (n = 23) but one patient rated the cosmetic outcome (mean 1.4 years after cranioplasty) as excellent (70%, n = 16) or good (26%, n = 6). Intraoperative cast-molded reconstructive cranioplasty is a feasible, accurate, fast, and cost-efficient technique that results in excellent cosmetic outcomes, even with large and complex skull defects.

The extended diep flap: extending the possibilities for breast reconstruction with tissue from the lower abdomen

The classical DIEP-flap is considered state-of-the-art in microsurgical autologous breast reconstruction. Some patients may require additional volume to match the contralateral breast. This quality control study prospectively evaluates the feasibility and outcome of a surgical technique, which pursues the volumetric augmentation of the DIEP-flap by harvesting of additional subscarpal fat tissue cranial to the classical flap border.

Three-dimensional surface reconstruction within noncontact diffuse optical tomography using structured light

A main field in biomedical optics research is diffuse optical tomography, where intensity variations of the transmitted light traversing through tissue are detected. Mathematical models and reconstruction algorithms based on finite element methods and Monte Carlo simulations describe the light transport inside the tissue and determine differences in absorption and scattering coefficients. Precise knowledge of the sample's surface shape and orientation is required to provide boundary conditions for these techniques. We propose an integrated method based on structured light three-dimensional (3-D) scanning that provides detailed surface information of the object, which is usable for volume mesh creation and allows the normalization of the intensity dispersion between surface and camera. The experimental setup is complemented by polarization difference imaging to avoid overlaying byproducts caused by inter-reflections and multiple scattering in semitransparent tissue.