[Patella dislocation]. / Patellaluxation.

The patella dislocation is defined as a non-recurring or recurrent dislocation of the patella from the patella surface of the femur. In general the patella dislocates in the lateral direction. Patella dislocations are subdivided in congenital, habitual or traumatic dislocations. Furthermore patella dislocations are differentiated in recurrent and chronic dislocations. Etiology of patella dislocations is not consistent and can be due to genu valgum, patella dysplasia or patella alta etc. Frequently the patella reposes spontaneously after dislocation. Besides examination of the knee, x-ray and magnetic resonance tomography belong to clinical diagnostics of the knee joint. Decision between conservative and operative therapy is addicted to accompanying injuries like fractures or ligamental injuries.

Accuracy of registration techniques and vascular imaging modalities in fusion imaging for aortic endovascular interventions: a phantom study.

BACKGROUND: This study aimed to assess the error of different registration techniques and imaging modalities for fusion imaging of the aorta in a standardized setting using a anthropomorphic body phantom. MATERIALS AND METHODS: A phantom with the 3D printed vasculature of a patient suffering from an infrarenal aortic aneurysm was constructed. Pulsatile flow was generated via an external pump. CTA/MRA of the phantom was performed, and a virtual 3D vascular model was computed. Subsequently, fusion imaging was performed employing 3D-3D and 2D-3D registration techniques. Accuracy of the registration was evaluated from 7 right/left anterior oblique c-arm angulations using the agreement of centerlines and landmarks between the phantom vessels and the virtual 3D virtual vascular model. Differences between imaging modalities were assessed in a head-to-head comparison based on centerline deviation. Statistics included the comparison of means ± standard deviations, student's t-test, Bland-Altman analysis, and intraclass correlation coefficient for intra- and inter-reader analysis. RESULTS: 3D-3D registration was superior to 2D-3D registration, with the highest mean centerline deviation being 1.67 ± 0.24 mm compared to 4.47 ± 0.92 mm. The highest absolute deviation was 3.25 mm for 3D-3D and 6.25 mm for 2D-3D registration. Differences for all angulations between registration techniques reached statistical significance. A decrease in registration accuracy was observed for c-arm angulations beyond 30° right anterior oblique/left anterior oblique. All landmarks (100%) were correctly positioned using 3D-3D registration compared to 81% using 2D-3D registration. Differences in accuracy between CT and MRI were acceptably small. Intra- and inter-reader reliability was excellent. CONCLUSION: In the realm of registration techniques, the 3D-3D method proved more accurate than did the 2D-3D method. Based on our data, the use of 2D-3D registration for interventions with high registration quality requirements (e.g., fenestrated aortic repair procedures) cannot be fully recommended. Regarding imaging modalities, CTA and MRA can be used equivalently.

Development of an ultrasound-capable phantom with patient-specific 3D-printed vascular anatomy to simulate peripheral endovascular interventions.

PURPOSE: Today, ultrasound-guided peripheral endovascular interventions have the potential to be an alternative to conventional interventions that are still X-ray and contrast agent based. For the further development of this approach, a research environment is needed that represents the individual patient-specific endovascular properties as realistically as possible. Aim of the project was the construction of a phantom that combines ultrasound capabilities and the possibility to simulate peripheral endovascular interventions. MATERIAL AND METHODS: We designed a modular ultrasound-capable phantom with exchangeable patient specific vascular anatomy. For the manufacturing of the vascular pathologies, we used 3D printing technology. Subsequently, we evaluated the constructed simulator with regards to its application for endovascular development projects. RESULTS: We developed an ultrasound-capable phantom with an exchangeable 3D-printed segment of the femoral artery. This modality allows the study of several patient-specific 3D-printed pathologies. Compared to the flow properties of a human artery (male; age 28) the phantom shows realistic flow properties in the duplex ultrasound image. We proved the feasibility of the simulator by performing an ultrasound-guided endovascular procedure. Overall, the simulator showed realistic intervention conditions. CONCLUSIONS: With the help of the constructed simulator, new endovascular procedures and navigation systems, such as ultrasound-guided peripheral vascular interventions, can be further developed. Additionally, in our opinion, the use of such simulators can also reduce the need for animal experiments.

SkinDot: A modified full-skin transplantation technique.

Existing epidermal transplantation procedures applied in burn surgery or wound treatment, such as mesh grafting or the Meek method, do not lead to a restoration of all the skin layers. Dermal skin layers are indispensable in ensuring the quality and function of the transplanted skin as a frictional surface and a carrier of skin appendages such as hair, sweat glands, and sebaceous glands, as well as nerve receptors for detecting pressure, vibration, and temperature. Because of the restricted skin surface area that can be provided by the donor, full-skin transplants cannot be transplanted over a large area. Cultured skin procedures, based on skin cells cultivated in a laboratory, have not yet reached a stage of development where a complex full epidermal transplantation is possible. In particular, the introduction of skin appendages with a functional cell-to-cell communication has not been observed thus far in cultivated skin. Based on the Reverdin transplantation method, in which concave skin islands with epidermal and dermal parts are transplanted, Davis in 1910 described the transplantation of multiple 2-5 mm sized full-skin islands as a new method for the treatment of skin lesions. Further modifying this 100-year-old procedure, we developed a miniaturization and automation of the Davis transplantation method that started in 2011 and called it "SkinDot". In the following article we describe the effectiveness of the full-skin island transplant procedure in two patients. The transplantation of single 2-3 mm full-skin islands results in a full-skin equivalent without any limits on donor area and with a reduced donor morbidity.

[Vascular surgery in the elderly : What is possible? What is reasonable?] / Gefäßchirurgie bei alten Menschen : Was ist möglich? Was ist sinnvoll?

Nowadays vascular treatment of the elderly is a great challenge. Following the demographic change patients in the field of vascular surgery are becoming older and sicker. In addition to the actual main vascular pathology, the average patient arrives with a series of additional diagnoses that have an impact on the perioperative strategy, surgery and outcome of patients. This strategy becomes more and more challenging because on one hand there will be soon be no limits to treatment, which is attributable to the progress in endovascular surgery and on the other hand the question arises whether the feasible is reasonable? Within the scope of this article the problems of treatment of the elderly are presented and strategies and decisions for an individualized optimal therapy are proposed.