Treatment of the experimental scoliosis with external fixator

1.实验兔脊柱侧凸的形态学研究本研究的目的是通过实验研究脊柱侧凸的形态学变化。在10只家兔的x线成像下，以规则间隔将两根克氏针插入椎间盘，并在左侧平行插入两根克氏针。在这10只兔子中，有9只产生右侧凸胸腰椎或腰椎侧凸。在3只兔中，在插入k针后8至12周取出k针，发现脊柱侧凸是不可逆的。然而，在术后不到8周取出金属丝的4只兔子中，发现脊柱侧凸是可逆的。在另外2只兔中，虽然手术后上k线松动，但脊柱侧凸畸形仍然存在。在这个实验性脊柱侧凸模型中，在顶端凹侧的小面软骨的组织形态学上可见退行性改变。外固定在实验性脊柱侧凸中的作用本实验研究的目的是探讨脊柱外固定在脊柱侧凸中的作用。部分切除生长兔右侧两根或四根肋骨。4 - 6周后，出现中度右凸胸侧凸。然后，在7只兔子中，用基什纳丝将微型orthofix或fixano固定器连接到T9/10和L1/2。外固定前平均Cobb角为27.1度，安装固定架后初次矫正时平均Cobb角为13.6度。其中3例在术后超过8周时取出固定物。在取出固定架后，这些兔子只看到轻微的进行性椎体弯曲，与对照组相比，预防进展的效果相对较好。我们认为这种脊柱外固定治疗脊柱侧凸的效果是由于矫正了椎体顶端的轴向旋转而不是牵引力。

1.Morphological studies in experimental scoliosis in rabbitsThe prupose of this study was to investigate experimentally the morphological changes of scoliosis. In 10 rabbits, under X-ray imaging two Kirshner wires were inserted into intervertebral discs at regular intervals, together with two parallel wires on the left side. In 9 of these 10 rabbits, right convex thoracolumbar or lumbar scoliosis was produced. In 3 rabbits, the K-wires were removed between 8 and 12 weeks after insertion and the scoliosis was found to be irreversible. However in the 4 rabbits, from which the wires were removed at less than 8 weeks after the operation, then the scoliosis was foud to be reversible. In the other 2 rabbits, although the upper K-wire was loose after the operation, a scoliotic deformity remained. In this experimental scoliosis model, degenerative changes were seen in the facet cartilage on the apical concave side histomorphologically.2.External fixation in experimental scoliosisThe purpose of this experimental study was to investigate the effects of spinal external fixation in scoliosis. Two or four ribs on the right side of growing rabbits were partially resected. Between 4 and 6 weeks later, moderate right-convex thoracic scoliosis had developed.Then, in seven rabbits, a mini-Orthofix or fixano fixator was attached by Kischner wires to T9/10 and L1/2. The average Cobb angle was 27.1 degrees before external fixation, and was 13.6 degrees at initial correction just after attaching the fixator. In three of them, the fixators were removed at more than 8 weeks after the operation. Only slight progressive vertebral curvature was seen in these rabbits after removal of the fixator, with a relatively good effect of prophylaxis of progression compared to the controls. We propose that the effects of this spinal external fixation for scoliosis was due to correction of the axial rotation at the apical vertebra rather than to the traction force.