Comparative characteristics of sagittal balance in normal children and with spondylolisthesis

BACKGROUND: The measurement of sagittal parameters is an important part of preoperative planning and is also used to evaluate the results of surgical treatment. It is known that in spondylolisthesis (especially at high degrees) the sagittal parameters of the spine differ from those in healthy people. The difference in spinal-pelvic parameters in children and adults without orthopedic pathology has also been proven. One of the tasks of surgical treatment of spondylolisthesis is the restoration of sagittal balance or its maximum approximation to normal values. However, today there is no single accepted norm of sagittal parameters for children, therefore, the question of the optimal tactics of surgical treatment of spondylolisthesis in children remains open.

AIM: To determine the parameters of the sagittal balance in normal children and in children with spondylolisthesis.

MATERIAL AND METHODS: A retrospective analysis of postural radiographs of 68 children was performed. Patients were divided into 2 groups: group I — 43 patients from 8 to 17 years old without spinal pathology. Group II — 25 patients with spondylolisthesis from 8 to 17 years old. For each patient, the main spinal and pelvic parameters (PT; PI; SS; LL; PI-LL; TK) were measured and statistical analysis of the data was performed.

RESULTS: The study proved that the main parameters of the sagittal balance (PI, PT, SS, LL, TK, PI-LL) in children and adults without pathological deformities of the spinal column are statistically significantly different. Also, there are statistically significant differences between the parameters of the sagittal balance in children and adolescents without spinal pathology and with spondylolisthesis (PI, PT, SS, LL, TK, SFD, PI-LL). In patients with high grade spondylolisthesis, the parameters of thoracic kyphosis and lumbar lordosis are significantly reduced, which should be assessed as a compensatory mechanism for maintaining the vertical position of the body. Children with spondylolisthesis are characterized by a significantly higher PI value.

CONCLUSION: The sagittal parameters of the spine in children and adults are different, therefore, for correct preoperative planning, it is necessary to establish the norm of sagittal parameters for children. It is also necessary to take into account the high value of PI in children and adolescents with spondylolisthesis, which may be the etiological factor of this disease. The existing formulas for measuring sagittal balance for children with spondylolisthesis should be used with caution, because a high PI can lead to unreliable theoretical values of PT, SS, LL and TK. The cause of sagittal imbalance can be not only high degrees of spondylolisthesis, but also the tight hamstrings.