[Show abstract][Hide abstract] ABSTRACT: Intramedullary nailing is the treatment of choice for patients with femoral shaft fractures. However, there is an ongoing debate in multiple trauma patients with associated lung contusion when primary or secondary definitive stabilisation of the long bone fracture should be performed, as nailing is thought to play an important role in the pathogenesis of adult respiratory distress syndrome (ARDS). In a standardised sheep model, this study aimed to quantify the development of acute pulmonary endothelial changes, to assess the activation of polymorphonuclear leucocytes (PMNL) and to observe the effects on the coagulation system associated with the reamed nailing procedure. Furthermore, the effect of coexisting lung contusion in an experimental model was evaluated. The animals were randomly assigned to one of four different groups (6 animals/group). In control groups, only a sham operation (thoracotomy) was performed, whereas in study groups, lung contusion was induced prior to femoral stabilisation either by external fixation or reamed femoral nailing. Using bronchoalveolar lavage (BAL) pulmonary permeability changes were quantified and PMNL activation was assessed by chemiluminescence. Additionally PMNL diapedesis and interstitial lung oedema were determined by histological analysis. All animals were sacrificed 4 h after the start of the femoral instrumentation. Without an associated lung injury, instrumentation of the femoral canal with the reamed nailing technique induced a transient increase in pulmonary permeability. In the face of an induced lung contusion, reamed femoral nailing resulted in significant increases in PMNL activation, pulmonary permeability and interstitial lung oedema, compared with external fixation. Without pulmonary contusion, reaming of the femoral canal was associated with a transient increase in pulmonary permeability. This was exacerbated in the presence of lung contusion along with increased PMNL activation. External fixation did not provoke similar changes. The findings of this study support the view that reaming of the femoral canal should be avoided in polytrauma patients with severe chest trauma as it could act as an additional stimulus for adverse outcome. Temporary external fixation appears to be a safe method for fracture stabilisation until inflammatory and coagulatory disturbances after trauma have been normalized.
[Show abstract][Hide abstract] ABSTRACT: Several investigations over the past few years have shown that the importance of preserving the blood supply of the transport disc during segmental distraction has been overestimated. It was clearly demonstrated that distraction osteogenesis by local bone transportation could be achieved even with free bone grafts. So far, there have been no systematic investigations into how different types of free bone grafts vary in their function and suitability as transport discs in segmental craniofacial distraction. The aim of this study was to develop criteria to aid the clinician in selecting the most suitable free bone graft for distraction purposes.
Under general anesthesia, calvarial defects measuring 6 x 5 cm were created in 12 adult black head sheep in order to reconstruct them by segmental distraction using two different types of bone grafts as transport discs. Group 1 (n=6) received autotopical membranous bone of the calvarium as the transport segment, while group 2 (n=6) received heterotopical enchondral material from the iliac crest. Distraction was started postoperatively after 5 days at 0.6 mm/day and continued for 7 weeks. After a further 6 weeks of consolidation, the animals were killed and specimens examined macroscopically, radiographically and histologically.
The significantly better quality of bone regenerates of group 1 was clearly influenced by the significantly better stability of the transport disc's connection to the distraction device, the calvaria grafts showing better volume stability and better mechanical resistance during transport than the iliac bone. The influence of both types of bone grafts on the macro- and microstructure of the newly formed bone was clearly evident. The mineralization density of group 2 regenerates was significantly lower than that of group 1 specimens.
High mechanical stability of the bone graft is a very important point to consider when selecting a free graft for use as transport disc in local bone transport, especially if transport is necessary over long distances.
No preview · Article · Jan 2005 · Archives of Orthopaedic and Trauma Surgery
[Show abstract][Hide abstract] ABSTRACT: Thirty-two female mice used for embryo transfer or as controls received either metamizol or equal volumes of normal saline administered subcutaneously following induction of anaesthesia with ketamine-xylazine. Body weight was measured immediately before surgery, after 24 and after 48 h. The duration of the surgical anaesthesia was recorded and postoperative behavioural responses were measured. Comparison of the treatment groups revealed no significant differences in body weight and recovery times, nor were other signs of discomfort detected in either treatment group. It was concluded that administration of metamizol did not provide additional analgesia following embryo transfer in mice anaesthetized with ketamine-xylazine.
Full-text · Article · Feb 2004 · Laboratory Animals