Mandibular magnetic distractor: preclinical validation.

The feasibility of magnetic activation for mandibular distraction has been demonstrated previously. In this study, we developed a biocompatible device to evaluate the feasibility of distraction in cadaveric subjects and the functionality of the device in bench tests. To confirm, considering the dimension of the distractor, that the torque applied on the internal magnet would be sufficient to activate distraction osteogenesis we measured, for different distances, the transmitted torque between a magnet (internal and external). We evaluated the friction force of the device, and the resilience of the magnet to the sterilisation process. To confirm the feasibility of distraction with this device, we proceeded to cadaveric tests, and evaluated the satisfaction of four surgeons. The force applied to the moving plate was greater than 50 Newtons (N) with a friction coefficient of η=0.2. We determined a friction torque of 65.10-3 N.mm in the distractor mechanism and demonstrated that sterilisation did not alter the magnet. Mandibular distraction had been successfully achieved in cadaveric trials, and surgeons were satisfied. This new device could be implanted in human subjects, for clinical assay, after approval by the regulatory agencies. The use of this fully internalised device should improve patients' comfort.

Sagittal split ramus osteotomy-related biomechanical properties.

Sagittal split ramus osteotomy (SSRO) is one of the most common maxillofacial operations, and the technique relies on a directed fracture involving different biomechanical variables. The aim of this study was to find out the biomechanical characteristics involved during each step of sagittal split osteotomy. We sampled eight fully dentate human mandibles and used the right side for hardness tests and the left side for a traction-to-fracture test within an unfinished SSRO. Right sides were sampled in five parts underlying the corticotomy course and tested with a hardness testing automatic machine. The mean hardness measures ranked to 21.5HV (Hardness Vickers Unit): 17.8HV; 27.4HV; 22.7HV; 28.7HV; for the lingual, diagonal, vestibular, full ramus, and full body samples, respectively. Left sides were cut using Epker's technique, and split with an electromechanical testing machine. The higher values reached before fracture in the traction-to-fracture tests ranked to 99.1N/6.7mm; 137.2N/10.8mm; 36.2N/4.2mm; 93.0N/7.3mm; 74.0N/8.1mm; 78.1N/4.5mm; 90.9N/10.6mm; and 64.7N/4.1mm, respectively, for specimens I, II, III, IV, V, VI, VII and VIII. This study provides to our knowledge the first biomechanical characteristics of SSRO and proposes a reproducible method for evaluation.

RFLP diversity and relationships among traditional European maize populations.

Given the large extent of hybrid cultivation, the importance of conserving the diversity of crop genetic resources has given birth to numerous collections of old races. In the present paper, we conduct a molecular characterisation of a large collection of 488 European maize populations using the bulk RFLP analysis. The analysis of 23 RFLP loci showed a high allelic richness of 11.5 alleles per locus. Populations from eastern Europe (Poland, Austria, Germany, etc.) showed the lowest genetic diversity, a lower number of unique alleles and a higher percentage of fixed loci than populations from southern Europe. In fact, genetic diversity appeared higher in Southern regions where the first maize populations are thought to have been introduced. Molecular classification based on Rogers' distance (i.e. alleles frequencies) allowed us to distinguish three main clusters which were highly consistent with geographic origins. A Northeastern cluster grouped together early or intermediate populations from Northeastern countries and the Balkans, a southeastern cluster joined late and partially dent populations from Greece and Italy, and, a southwestern cluster was made up of early flint populations from northern Spain, Portugal and the Pyrenees. A correlation between allelic frequencies at some loci and latitude and/or longitude was observed. Such tendencies may reflect the direction of gene flow between different races of maize: for instance, North American (Northern flint) and Caribbean populations were introduced, respectively, to northern and southern Europe, in the past.

Postoperative pain relief; a new approach: narcotics compared with non-steroidal anti-inflammatory drugs.

The pain relief provided by regular intramuscular diclofenac and on demand intramuscular papaveretum was compared over a 48 h postoperative period in 114 patients undergoing total hip replacement. The study was of a randomised, single-blind, between-group design. Patients were assessed by a surgeon, physiotherapist and nursing staff. Diclofenac was more effective than papaveretum in pain control (P less than 0.001), wound tenderness (P less than 0.01), awareness (P less than 0.001) and mobilisation (P less than 0.01). Wound drainage (P greater than 0.05) and wound oedema (P greater than 0.05) were not significantly different in the two treatments. Gastrointestinal complications were encountered in both groups; two patients on diclofenac had to be withdrawn because of them. The use of diclofenac given as a postoperative analgesic is rewarding, particularly in patients undergoing musculoskeletal procedures. Patients will be more comfortable and will mobilise better during their whole postoperative course.