Revista de la Asociación Argentina de Ortopedia y Traumatología
versión On-line ISSN 1852-7434
ORTIZ, Pablo N. et al. Thoracic sagital balance after instrumentation with pedicle screws in Lenke 1a and b curves. Rev. Asoc. Argent. Ortop. Traumatol. [online]. 2009, vol.74, n.2, pp. 117-121. ISSN 1852-7434.
Background: The instrumentation used to correct deformities is effective in the coronal, but more uncertain in the sagittal plane. Our purpose is to evaluate the mechanical effect of pedicle screws on the sagittal alignment of patients with Idiopathic Scoliosis (IS) for Lenke 1A and B curves. Methods: This is a retrospective radiographic cohort study involving 31 patients with posterior correction of right thoracic curves using pedicle screws. The sagittal contour was measured pre-and post-op with the Cobb method.We used the Lenke (Minus - Plus and Normal) classification. Statistical analysis was performed with INSTAT. The Student's paired test and the Wilcoxon test were used. Values are expressed as the mean ± 1 standard deviation. A p value of < 0.05. was considered significant. Results: The average degrees of pre-and post-op thoracic kyphosis were 31 ± 15º and 19 ± 9º, respectively, with an average difference of 11.7º. We found a statistically significant decrease in the average degree value (p <0.0001). The decrease in degrees of kyphosis led to statistically significant group changes (p < 0.04). Conclusions: The lordosing tendency with pedicle screws was statistically significant. Therefore the alternatives and strategies at hand when deciding the appropriate treatment for this type of deformities are key, since success is based not only on achieving the right coronal plane but also a balanced spine, attaching importance to the sagittal plane to guaranty good long-term results.
Palabras clave : Sagittal balance; Pedicle screws; Lordosing tendency.