Bone is a highly vascularized tissue, and its development, maturation, remodeling, and regeneration are dependent on a tight regulation of blood vessel supply. This condition also has to be taken into consideration in the context of the development of artificial tissue substitutes. In classic tissue engineering, bone-forming cells such as primary osteoblasts or mesenchymal stem cells are introduced into suitable scaffolds and implanted in order to treat critical-size bone defects. However, such tissue substitutes are initially avascular. Because of the occurrence of hypoxic conditions, especially in larger tissue substitutes, this leads to the death of the implanted cells. Therefore, it is necessary to devise vascularization strategies aiming at fast and efficient vascularization of implanted artificial tissues. In this review article, we present and discuss the current vascularization strategies in bone tissue engineering. These are based on the use of angiogenic growth factors, the co-implantation of blood vessel forming cells, the ex vivo microfabrication of blood vessels by means of bioprinting, and surgical methods for creating surgically transferable composite tissues.

The biopsy technique of choice in soft tissue sarcoma (STS) diagnosis is controversial. We examined the diagnostic accuracy of percutaneous core needle biopsy (CNB) and compared it to open incisional biopsy. A retrospective study included 91 incisional biopsies and 102 CNBs. A pair-match investigation was conducted on 19 patient pairs, comparing sensitivity, specificity, and diagnostic accuracy. Furthermore, we investigated the role of molecular pathology in sarcoma diagnostics. In 81/91 (89%) patients with incisional biopsy, the entity was confirmed by definitive pathology, whereas this was the case in 89/102 (87%) CNB patients (p = 0.52). Grading remained unchanged in 46/55 (84%) of incisional and 54/62 (87%) of CNBs (p = 0.61). The pair matched analysis showed that the correct entity was determined in 96% of incisional and 97.6% of core needle biopsies. The time between the initial consultation and the interdisciplinary tumor board's treatment recommendation was shorter in core needle biopsies (8.37 vs. 15.63 days; p < 0.002). Incisional biopsies led to two wound infections and one hematoma, whereas wound infection occurred in one patient after CNB. CNB leads to faster diagnosis while reaching the same histological accuracy and is less burdensome for patients. Still, surgeons need to remain aware of the possibility of biopsy failure.

Background: Three-dimensional (3D) scanning is an established method of breast volume estimation. However, this method can never be entirely precise, since the thoracic wall cannot be imaged by the surface scanner. Current methods rely on interpolation of the posterior breast border from the surrounding thoracic wall. Here, we present a novel method to calculate the posterior border and increase the accuracy of the measurement. Methods: Using principal component analysis, computed tomography images were used to build a statistical shape model (SSM) of the thoracic wall. The model was fitted to 3D images and the missing thoracic wall curvature interpolated (indirect volumetry). The calculations were evaluated by ordinary least squares regression between the preoperative and postoperative volume differences and the resection weights in breast reduction surgery (N = 36). Also, an SSM of the breast was developed, allowing direct volumetry. Magnetic-resonance images (MRI) and 3D scans were acquired from 5 patients in order to validate the direct 3D volumetry. Results: Volumetry based on a SSM exhibited a higher determination coefficient (R² = 0,737) than the interpolation method (R² = 0,404). The methods were not equivalent (p = 0.75), suggesting that the methods significantly differ. There was no influence of BMI on the correlation in either method. The MRI volumetry had a strong correlation with the 3D volumetry (R² = 0,978). Conclusion: The SSM-based method of posterior breast border calculation is reliable and superior to the currently used method of interpolation. It should serve as a basis of software applications aiming at calculation of breast volume from 3D surface scanning data.