The aim of this study was to examine whether asymmetric loading
influences macrophage elastase (MMP12) expression in different parts
of a rat tail intervertebral disc and growth plate and if MMP12
expression is correlated with the severity of the deformity. A wedge deformity between the ninth and tenth tail vertebrae
was produced with an Ilizarov-type mini external fixator in 45 female
Wistar rats, matched for their age and weight. Three groups were
created according to the degree of deformity (10°, 30° and 50°).
A total of 30 discs and vertebrae were evaluated immunohistochemically
for immunolocalisation of MMP12 expression, and 15 discs were analysed
by western blot and zymography in order to detect pro- and active
MMP12.Objectives
Methods
The response of the intervertebral disc to asymmetric forces may accelerate degeneration through changes in the matrix. Macroscopically, the disc sustains structural changes that may play a part in the progression of a scoliotic curve. Molecularly, disc degeneration is the outcome of the action of matrix metalloproteases (MMPs), members of a family of enzymes that bring about the degradation of extracellular matrix components. In this study we measured in vivo the expression of MMPs in a rat scoliotic intervertebral disc and studied the effect of the degree of the deformity on their production. Asymmetric forces were applied in the intervertebral disc between the ninth and tenth vertebrae at the base of a rat tail with the use of a mini Ilizarov external fixator, under anaesthesia. Animals were categorised into three groups according to the degree of the deformity. In group I, the deformity that was applied on the intervertebral disc was 10°, in group II 30°, and in group III 50°. All the animals used were female Wistar rats before adulthood, to take into account the effect of growth for the study of intervertebral disc changes. The intact intervertebral discs outside the fixator were used as controls. After the rats' death on day 35, the tails were prepared and analysed with an immunohistochemical protocol for chromogenic detection and location of MMPs 1 and 12 in tissue sections of the intervertebral discs.Introduction
Methods
This paper evaluates severe normal trunk asymmetry (TA) by higher and lower body mass index (BMI) values in 5953 adolescents age 11–17 years (boys 2939, girls 3014) whilst standing forward bending (FB) and sitting FB during screening for scoliosis. TA was measured as angle of trunk inclinations (ATIs) across the back (thoracic, thoracolumbar and lumbar) with abnormality defined as 2 standard deviations or more. The findings for sitting FB position are reported because the readings express TA free from any leg-length inequality. Relatively lower BMIs are associated statistically with
excess of abnormal TAs, and later menarche. BMI is known to be linked to puberty timing and energy balance but not to TAs in healthy students. Similar to girls with adolescent idiopathic scoliosis, we suggest that severe TA is caused by a genetically-determined selectively increased hypothalamic sensitivity to leptin with asymmetry as an adverse hormetic response, exacerbated by presumed lower circulating leptin levels associated with relatively lower BMIs. The asymmetry is expressed bilaterally via the sympathetic nervous system to produce left-right asymmetry in ribs and/or vertebrae leading to severe TA when beyond the capacity of postural mechanisms of the somatic nervous system to control the shape distortion of the trunk
2.1 The examined children. 4345 students (2183 girls and 2158 boys), 6 – 18 years of age were examined during the school-screening program for scoliosis. 2.2 The measurements. A protocol with a checklist is filled for each student in which handedness and truncal asymmetry is included. The probability of existence of scoliosis in the child and the recommendation for further clinical and radiological assessment at hospital is based on the amount of the recorded truncal asymmetry. The sitting and standing forward bending test is performed using the Pruijs scoliometer, on which reading ≥7° is a threshold for recommendation for reexamination. Truncal asymmetry was recorded for thoracic, thoracolumbar and lumbar region. 2.3 The statistical analysis. The techniques used for the study of the sample of children included cross tabulation and ÷2.
In this paper the results of correction of bone deformities using the llizarov methods, are presented. Fifty-nine patients, 42 with malunion and 17 with mal-nonunion of tibia or femur were operated upon using the llizarov circular fixator. Another 28 cases were corrected using a unilateral device. There were: a) 30 angular deformities, 18 of which were combined with shortening, b) 21 angular deformities associated with translation and c) 36 complex, deformities including angulation, translation, shortening and malrotation. Two rings above and two below the apex of the deformity were always required. Different types of hinges were used between them, depending on the type of the deformity. The corticotomy was performed at the apex of the deformity for the majority of the cases. In 18 patients with hypovascular and eburnated bone, or bone covered with soft tissue of poor quality, the corticotomy was done more proximal or more distal to the apex of the deformity. In complex deformities the correction sequence was: 1) correction of angulation and shortening simultaneously, 2) correction of rotation, 3) and finally correction of translation. The true plane of the deformity and the plane of placement of the hinges were determined by a computerized formula that we developed. The deformities were corrected in all cases in which the hinges were placed at the correct position but in 5 cases we had to re-orient the hinges in order to achieve the correction. The corticotomy or pseudarthrosis consolidated in all cases. Residual leg length discrepancy remained in three patients, not exceeding 135 cm. Great care was taken to prevent complications during operation as well as during the post operative period. However, there were numerous obstacles, problems and true complications. All these were managed aggressively as soon as they appeared. The final results were very satisfactory. We conclude that the revolutionary llizarov methods can solve bone deformity problems that cannot be faced by the traditional methods. It is critically important to place the hinges at the correct position in order to achieve the desired correction. Our computer program definitely helps to this purpose. The surgeon must always be vigilant in order to prevent complications and to deal with them immediately.