[Carpal tunnel syndrome: correlation between median nerve relative constriction in the carpal tunnel and distal motor latency]. / Karpaltunnelsyndrom: Korrelation zwischen der relativen Einengung des N. medianus im Karpalkanal und der distalen motorischen Latenz.

PURPOSE: This study analyses the correlation between the constriction in the substance of the median nerve in the carpal tunnel and distal motor latency, gender and age of patients with a carpal tunnel syndrome. PATIENTS AND METHODS: In 82 patients (59 women and 23 men with an average age of 66.6 (41-89) years) with an electrophysiologically verified carpal tunnel syndrome undergoing open carpal tunnel release, the diameter of the median nerve was measured at the narrowest point of the nerve at the level of the constriction and the widest point of the nerve proximal to the constriction. The grade of nerve constriction was the ratio between the diameter at the level of the constriction and the widest diameter proximal to the constriction. Additionally, the distance from the distal wrist crease to the beginning of the constriction was measured. The grade of constriction was correlated with the patients' distal motor latency, gender and age. RESULTS: The diameter of the median nerve at the narrowest point of the constriction averaged 6.0 (SD 1.1) mm; the diameter at the widest point proximal to the constriction was 7.6 (SD 1.5) mm. The distance from the distal wrist crease to the beginning of the constriction averaged 17.6 (SD 3.7) mm. Grade of nerve constriction did not correlate with distal motor latency. However, there was a correlation between patient age and distal motor latency. CONCLUSION: The grade of nerve constriction cannot be estimated based on the severity of prolongation of distal motor latency. There is a positive correlation between the age of patients with a carpal tunnel syndrome and distal motor latency.

Carbon-Fibre-Reinforced SiC Composite (C/SiSiC) as an Alternative Material for Endoprosthesis: Fabrication, Mechanical and In-Vitro Biological Properties.

Particle-induced periprosthetic osteolysis and subsequent aseptic implant loosening are a major cause of compromising the long-term results of total joint replacements. To date, no implant has been able to mirror radically the tribological factors (friction/lubrication/wear) of in vivo tribological pairings. Carbon-Fibre Reinforced SiC-Composites (C/SiSiC), a material primarily developed for brake technology, has the opportunity to fulfil this requirement. Until now, the material itself has not been used in medicine. The aim of this investigation was to test the suitability of C/SiSiC ceramics as a new material for bearing couples in endoprosthetics. After the preparation of the composites flexural strength was determined as well as the Young's-modulus and the coefficient of friction. To investigate in vitro biological properties, MG 63 and primary human osteoblasts were cultured on C/SiSiC composites. To review the proliferation, the cytotoxicity standardized tests were used. The cell morphology was observed by light microscopy, ESEM, confocal and 3D-laserscanning microscopy. C/SiSiC possesses a high resistance to wear. Cells exhibited no significant alterations in morphology. Vitality was not impaired by contact with the ceramic composite. There was no higher cytotoxicity to observe. Regarding these results, C/SiSiC ceramics seem to be biologically and mechanically appropriate for orthopaedic applications.