The influence of vision and support base on balance during quiet standing in patients with adolescent idiopathic scoliosis before and after posterior spinal fusion.

BACKGROUND CONTEXT: Scoliosis is the most common postural alteration in adolescence and is characterized by deviations of the spine in three planes. Surgical treatment based on arthrodesis has been developed, but the effects of such restructuring on the systems involved in postural control need to be better understood. PURPOSE: To assess the influence of vision and the support base on balance in the quiet standing position in adolescents awaiting surgical treatment for idiopathic scoliosis. STUDY DESIGN/SETTING: Longitudinal study/Ribeirão Preto Clinics Hospital (HC-FMRP-USP) and Laboratory of Assessment and Rehabilitation of Equilibrium at the FMRP-USP. PATIENT SAMPLE: Adolescent idiopathic scoliosis patients and controls. OUTCOME MEASURES: Center of pressure (CoP) sway area of the 95% confidence ellipse. METHODS: Thirty female adolescents were divided into two groups according to their spinal alignment: control (n=15) and scoliosis groups (SGs) (n=15). The subjects with scoliosis were evaluated before and 7, 30, 60, and 90 days after surgery; the controls were evaluated once. The area of CoP oscillation was measured with the eyes open and closed and with two different support bases (feet apart or together). The force platform was purchased with funding support (US $8,375.00) provided by the Research Foundation of São Paulo (FAPESP). The study sponsors had no involvement in the study. Data were collected from the force platform and then statistically assessed through a linear model analysis of mixed effects. RESULTS: Data reveal that subjects in the SG oscillated more than controls, and postsurgery subjects had more oscillation than presurgery subjects. The results also indicated that both groups (control and scoliosis) showed more oscillation among those subjects with feet apart and eyes closed, but subjects with scoliosis were more affected by vision deprivation than by a reduced support base. CONCLUSIONS: Our results indicate that adolescents with idiopathic scoliosis are more dependent on visual information and that surgical correction does not change this relationship.

In vitro proliferation and osteoblastic phenotype expression of cells derived from human vertebral lamina and iliac crest.

STUDY DESIGN: Osteoblastic cells derived from vertebral lamina and iliac crest were isolated and cultured under the same conditions (osteogenic medium, pH, temperature, and CO2 levels). OBJECTIVE: To compare proliferation and expression of osteoblastic phenotype of cells derived from vertebral lamina and iliac grafting. SUMMARY OF BACKGROUND DATA: Many factors play a role in the success of bone graft in spinal fusion including osteoblastic cell population. Two common sources of graft are vertebral lamina and iliac crest, however, differences in proliferation and osteoblastic phenotype expression between cells from these sites have not been investigated. METHODS: Cells obtained from cancellous bone of both vertebral lamina and iliac crest were cultured and proliferation was evaluated by direct cell counting and viability detected by Trypan blue. Alkaline phosphatase (ALP) activity was evaluated by thymolphthalein release from thymolphthalein monophosphate and matrix mineralization by staining with alizarin red S. Gene expression of ALP, osteocalcin, runt-related transcription factor 2, Msh homeobox 2, bone morphogenetic protein 7, intercellular adhesion molecule 1 precursor, osteoprotegerin, and receptor activator of NF-kB ligand was analyzed by real-time PCR. All comparisons were donor-matched. RESULTS: Proliferation was greater at days 7 and 10 in cells from vertebral lamina compared with ones from iliac crest without difference in cell viability. ALP activity was higher in cells from vertebral lamina compared with cells from iliac crest at days 7 and 10. At 21 days, mineralized matrix was higher in cells derived from vertebral lamina than from iliac crest. At day 7, gene expression of ALP, osteocalcin, runt-related transcription factor 2, Msh homeobox 2, bone morphogenetic protein 7, intercellular adhesion molecule 1 precursor, receptor activator of NF-kB ligand, and osteoprotegerin was higher in cells derived from vertebral lamina compared with iliac crest. CONCLUSION: Cell proliferation and osteoblastic phenotype development in cells derived from cancellous bone were more exuberant in cultures of vertebral lamina than of iliac crest.