Octyl-a-cyanoacrylate adhesive in the treatment of tibial transverse fracture in rabbits / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To observe the effect of octyl-a-cyanoacrylate upon bone healing and its degradation in vitro after middle tibial transverse fracture in rabbitsì and to establish treatment of higher efficacy with the application of octyl-a-cyanoacrylate.</p><p><b>METHODS</b>Middle tibial transverse fracture model of New Zealand rabbits was established. In the experimental group, internal fixation with 2 mm Kirschner wires was performed and the broken ends were fixed with octyl-a-cyanoacrylate. In the control group, only internal fixation with 2 mm Kirschner wires was conducted. Animals were killed at preset time intervals of 2, 4, 6, 8, 10 and 12 weeks postoperatively and samples were harvested.</p><p><b>RESULTS</b>Two weeks after operation, clear fracture lines were observed in both the experimental and the control groups. Fibrous soft tissue connection was noted between the broken ends and there was soft tissue adhesion around the fracture site. There was no callus formation and the broken ends were surrounded by adhesive soft tissues. Obvious external callus formation was confirmed at 8 weeks after operation in both groups with partial disappearance of fracture lines. Ten and twelve weeks after the operation, fracture lines disappeared completely and there was obvious external callus formation and bone union. In the fourth week, fibrous cells and chondrocytes were found to grow into the colloid and surround it at the 6th week. The adhesive material was degraded and gradually absorbed at the 8th week. Chondrification was observed.</p><p><b>CONCLUSIONS</b>Two weeks after fixation for tibial fracture in rabbits, octyl-a-cyanoacrylate begins in vivo degradation. Chondrocytes and fibrocytes gradually grow into the degradation area and surround the adhesive material, which broke into pieces at 8 weeks. Complete degradation and disappearance of the adhesive material is present between 10 and 12 weeks. No barrier effect hampering fracture healing is noted.</p>

Observation and establishment of an animal model of tractive spinal cord injury in rats / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To establish an animal model of tractive spinal cord injury in rats in order to investigate its pathophysiological changes and clinical significance.</p><p><b>METHODS</b>T(12)-L(3) spines were tracted longitudinally with a special spinal retractor that was put on the proccessus transverses of T(12)-L(3) vertebrae of the rat after exposing T(13)-L(2) spinal cord via dual laminectomy. At the same tine, the spinal cord function was monitored by cortical somatosensory evoked potential (CSEP). Rats were randomly divided into four groups according to the amplitude of CSEP P(1)-N(1) wave, the amount of the decreasing P(1)-N(1) wave was 30% (the 30% group), 50% (the 50% group) and 70% (the 70% group), respectively. After traction, the changes of the neural behavioral function in rats were observed and the morphological structure of the spinal cord was analyzed quantitatively with image analysis system of computer.</p><p><b>RESULTS</b>With traction of spine, compared with the control group, the 30% group had no marked difference in combined behavioral score (CBS), neuron count, section area of neuron and Nissl body density, but the 50% and 70% groups had marked difference (P<0.01). Light microscope showed that the neuron volume was slightly small and the Nissl body was reduced lightly in the 30% group; the neuron space was enlarged and the neuron was degenerative, reductive, and dissolved, and the spinal cord structure was destroyed in the 50% and 70% groups.</p><p><b>CONCLUSIONS</b>The animal model of tractive spinal cord injury in rats is a reproducible, graded and clinic mimic. The model in this article provides a valuable assistance in further understanding etiopathology and screening effective measures of therapy and prophylaxis of the injury.</p>