Papers by Keyword: Cyst

Abstract: The deformation of the human breast, especially that of the female, under variable pressure conditions, has been a recent focus for researchers, both in the computational biomechanics, computational biology and the health sector. When the deformation of the breast is large, it hampers suitable cyst tracing as a mammographic biopsy precontrive data. Finite element methods (FEM) has been instrumental in the currently studied practices to trail nodules dislocation. However, the effect of breast material constitution, especially that of a fibrocystic composition, on the biomechanical response of these nodules has gained less attention. The present study is aimed at developing a finite element fibrocystic breast model within the frame of biosolid mechanics and material hyperelasticity to model the breast deformation at finite strain. The geometry of a healthy stress‐free breast is modelled from a magnetic resonance image (MRI) using tissues deformations measurements and solid modelling technology. Results show that the incompressible Neo-Hookean and Mooney-Rivlin constitutive models can approximate large deformation of a stressed breast. In addition to the areola (i.e. nipple base), the surrounding area of the cyst together with its interface with the breast tissue is the maximum stressed region when the breast is subjected to compressive pressure. This effect can lead to an internal tear of the breast that could degenerate to malignant tissue.

Abstract: Anterior cruciate ligament (ACL) reconstruction technique was under tremendous improvement during last 10 years; anatomical versus transtibial technique gradually increased, with soft tissue graft overcoming bone-tendon-bone, and biodegradable exceeding metallic implants. Still, complications related to ACL reconstruction are reported; one of it is pretibial cyst formation. Pretibial cyst formation is reported to develop between 2 and 5 years post-operation. We report a case in which the cyst was developed at 2 years after surgery; a biocomposite screw was used for fixation on tibial site, in an ACL reconstruction done with soft tissue autograft. The MRI examination suggested the diagnostic, which was confirmed by histological examination of the cyst. The screw suffered multiple fragmentation; the remnants were retrieved and analyzed. The knee stability was not affected by the cyst development. After retrieval of the screw and appropriate rehabilitation, the patient recovery was complete. The presented case confirms that even biocomposite screw may be related to these sorts of complications, mainly related to plain biodegradable screws. The case offers a point of start for analysis of the literature. A precise ethology of this kind of complications is still unknown; a lot of theories have been developed, two of them seem to be related to our case. Technical improvement together with long time surveillance of cases in which biocomposite implants were used may improve our knowledge concerning the fate of these implants.

Abstract: Autogenous bone grafts are considered to be the gold standard in maxillo-facial surgery. However, drawbacks of donor site morbidity and unpredictable rates of resorbtion often limit their use. In vivo tests have shown that 45S5 bioactive glass particles placed in critical size bone defects lead to regeneration of new bone that has the structural characteristics and architecture of mature trabecular bone. In vitro tests using primary osteoblast cultures have shown that the bioactive glass particles release ionic dissolution products that provide genetic stimuli that control osteoblast cell cycles and lead to rapid growth of mineralized bone nodules. These in vitro and in vivo results led to approval of use of bioactive glass particles and monolithic bioactive glass implants for use in maxillo-facial reconstructions after removal of bone cysts and trauma, as described by several case histories.