The analysis of forces needed for the suturing of elliptical skin wounds.

There is a lack of information regarding the forces required for suturing human wounds. The knowledge of suturing forces serves as complementary information for setting up the limiting geometry when using tissue adhesives and it might also be used in robot-assisted surgery. The main purpose of this paper was to evaluate the forces required for suturing selected skin wounds. An elliptical wound was chosen for our study. In this study a numerical analysis and in vivo experiments were performed. Regarding the numerical models, the maximum forces occurred in the middle of the elliptical wound in all cases. In the case of highest pre-stress used in these analyses the maximal force varied from 0.5 N for the smallest wound (30 × 5 mm) to 1.5 N for the largest wound (30 × 15 mm). The maximum peak force for the wound with a size of 46 × 13 mm was 3.2 N. The minimum peak force for the wound with a size of 36 × 5 mm was 1.1 N.

Influence of the orientation of the Osstell transducer during measurement of dental implant stability using resonance frequency analysis: a numerical approach.

Stability of dental implants is measured by means of the Osstell device using a method of resonance frequency analysis. The aim of the study was to evaluate the role of direction-dependence of the Osstell transducer. For this purpose, a set of parametrical finite element analyses has been used. When rotating the transducer around the vertical axis the crucial phenomenon is the change in behavior of the system, which occurs in positions between 30 degrees and 80 degrees to the long axis of the alveolar crest. It seems from the presented results that, when measuring approximately perpendicularly to this long axis, the deviation from the ideal perpendicular position must not exceed 30 degrees. In this case, the first resonance frequency is recorded. When measuring in the approximately parallel position to the long axis of the alveolar crest, the second resonance frequency is recorded. The deviation from the ideal parallel position must not exceed 10 degrees. These values are not comparable with the previous ones.

Single-stage total C-2 intralesional spondylectomy for chordoma with three-column reconstruction. Technical note.

Chordomas are locally invasive, malignant bone tumors that rarely occur in the cervical spine. En bloc resection or even fully resecting the tumor along its margin offers improved patient survival and a potential disease cure. Complete resection of tumors involving the upper cervical vertebrae requires a combined anterior-posterior approach but is complicated by the presence of vertebral arteries (VAs). In addition, reconstruction of the postresection defect may be prone to failure. The authors present a case of a chordoma involving the axis that was treated using a single-stage total intralesional C-2 spondylectomy with preservation of both VAs because the patient did not tolerate a preoperative occlusion test. A three-column reconstruction technique is also presented.