Small bowel lengthening by mechanical distraction.

To evaluate whether the small bowel can be distracted by mechanical stress in analogy to limb lengthening by osteodistraction, a gut-lengthening apparatus was designed. This distractor was placed at the antimesenterical side of a defined jejunum segment in rabbits. Distraction was performed by 1 mm lengthening of the distractor once daily using extracorporal screws. An effective gut lengthening was achieved of 9.9 +/- 0.5 mm (approximately 100%) within 3 weeks. Treated animals gained weight and remained in good general condition. Fasting plasma levels of cholecystokinin, neurotensin, glucagon-like peptide-1, gastric inhibitory polypeptide, and insulin remained unaffected. Postoperative factor XIII levels were significantly diminished and gastrin was elevated during gut distraction. DNA and protein concentrations in the mucosa of the distracted gut segments corresponded to controls. Mucosal lactase and saccharase activities were reduced. In the distracted bowel segments total tunica muscularis thickness was more than doubled due to muscle cell hypertrophy. In distracted segments villous width was increased. Detection of proliferating mucosal crypt cells utilizing BrdUrd labeling revealed no effects. In conclusion, small gut lengthening by mechanical distraction is possible without major changes in gut morphology. This technique may hint a novel experimental approach for the treatment of short bowel syndrome.

[Technical measuring procedures for 3-dimensional movement analysis of experimentally-induced fractures of the thoracolumbar spine and initial results]. / Messtechnisches Verfahren zur dreidimensionalen Bewegungsanalyse von experimentell erzeugten Frakturen der thorakolumbalen Wirbelsäule und erste Ergebnisse.

Biomechanics and motion following fractures of the thoracolumbar spine have not yet been clarified. The motion acts in 6 degrees of freedom: three rotations and three translations parallel to the system of coordinates. The problem is to measure each rotation and each translation individually. This requires a method allowing precise three-dimensional evaluation of the motion that takes place in the genesis of a spine fracture. This technique should not influence the experiment, should give exact data over a wide range of measurement and, finally, should require as little equipment as possible. To fulfil these conditions we have developed a "double cube" model. Cadaver spine units from T11 to L3 were used. T11 was blocked with T12 and L2 with L3. These blocks were used to fix the spine in a testing machine so that a wedge-compression fracture could be produced in L1. Dorsal to each of the blocks one cube was mounted, the caudal one fixed while the cranial one could be moved by the machine. In the caudal cube a right-handed cartesian system of coordinates was defined, in which the vertebrate above would move and break. This technique can be used to describe either physiological or fracture experiments or, for example, to compare stability tests for different fixation devices. It is demonstrated that precise three-dimensional description of the biomechanics of vertebral fractures is possible with little and simple equipment. The cubes in this model are easily to integrate in the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

[Sonographic imaging of meniscus lesions. An experimental study]. / Die sonographische Darstellung der Meniskusläsion. Eine experimentelle Studie.

There is still no general agreement on the value of ultrasonographic visualization of pathologic changes in the knee menisci. Some examiners report on large patient collectives in which it has yielded accurate diagnoses in 90% of cases. Other authors describe much higher failure rates and unreliable imaging of meniscal lesions. The aim of this experimental study was to determine how reliable the imaging of such lesions is, which of the different types can be recognized, and what their ultrasonic morphological characteristics are. To this end, the examinations were performed on isolated menisci in a waterbath to avoid artefacts that might be caused by the tissues surrounding the meniscus in situ. It was shown that all types of lesion except the transverse rupture could be visualized and localized reliably. The different types of meniscal injuries all produce the same sort of appearance on the screen: a hard, glaring reflection of sound waves. The necessity of using a 7.5-MHz sector, or curved-array transducer for the examination is emphasized.

[Progress in external fixation]. / Fortschritte in der externen Stabilisierung.

The monofixateur opens up avenues in external skeleton fixation. Proceeding from Lambotte's groundwork and from the given anatomical conditions and biomechanical requirements, a system has been developed that ensures maximum effectiveness with a minimum of mechanical means and operative procedure. Of particular importance is the dual-application feature of the monofixateur system: it is equally indicated for static as well as dynamic fixation, and is quickly and easily adapted from one function to the other at any time as called for by the treatment process. This system provides for dynamic function when applied without fixation clamping jaws on one of the major bone fragments. It allows for functional axial compression to be exerted through muscle contraction and pressure, while simultaneously excluding the possibility of bending and rotation, thus effectively promoting the healing process. The monofixateur is indicated for treatment of closed, open and infected fractures, pseudarthrosis, osteotomy adaption, arthrodesis and joint transfixations. In brief, the advantages of external fixation by the monofixateur may be summarized as follows: Simple mechanical design affording precise function. High stability with small number of fixation components. Unilateral assembly of device in position biomechanically favorable. Static or dynamic fixation. Little patient impairment.