Evaluation of postural function disorders of the spine in orthostatic stereotypes
There is no unified system for assessing the functional mobility (lability) of the spine to diagnose its hypermobility, pathological mobility and instability. In the absence of such a system, biomechanical characteristics of spinal segments, revealed in normal individuals and by clinical examination of patients, are instrumentally and metrically incommensurable with its kinematic characteristics detected in functional radiographs. Purpose Development of criteria and methods to assess the postural function (lability) of the spine and the rigidity of its deformations for their consideration and suggestion as a metric standard Materials and methods Patients (n = 43) aged 9 to 23 years with clinical and radiological signs of spinal curvatures of grades 2 to 4 (according to Chaklin) and orthopedically healthy subjects of the same age (n = 79) were examined. Instrumental analysis of the monitored postural activity of the trunk and spine in orthostatics was carried out by the optoelectronic method KOMOT. Results and discussion It was established that the postural characteristics of spinal deformities are significantly different in sample populations in terms of expected magnitude of curvature and variability. If in postural and in sample sets the angular characteristics of spinal curves obey the law of normal distribution, then their postural variation in samples tends to a power-law type of distribution. In orthostatic position, the power-law type of the variability distribution was reliably manifested not only with respect to the angular characteristics of spinal curvatures, but also with respect to the variability of a number of other postural parameters. As a result of the analysis of the distribution of random variables characterizing the angular curves of the spine in orthostatic stereotypes and the dependencies between their variation and the expected values in sample populations, a quantitative topographic evaluation of the functional mobility of the spine according to the index of postural lability (IPL) was proposed. Conclusion To adequately assess the postural function of the spine (its lability), it is necessary to have not only a single-stance recording of the parameters under study but to repeatedly register them in a feasible prolonged examination. Only mathematically expected values and root-mean-square deviations of angular parameters reflect more fully the state of spinal curvatures and have the necessary and sufficient diagnostic information. A quantitative topographic estimation of the functional mobility of the spine according to index of postural lability (IPL) is suggested. Normally, IPL is in the range of 30 to 75 %. If the index is less than 30 %, the spine is hypermobile; if it is more than 75 %, the spinal column is rigid.