Introduction: We previously demonstrated that pelvis, hips and shoulders motion were significantly reduced in adolescent idiopathic scoliosis (AIS) patients with thoracolumbar/lumbar curve. Decreased muscular mechanical work (Wtot), increased energy cost (C) and prolonged timing activity of lumbo-pelvic muscles (LPMTA) were observed.
Objectifs: To evaluate the effect of spinal fusion on AIS gait mechanisms.
Materials and Methods: Nineteen AIS females (7 anterior spinal fusion [ASF], 12 posterior spinal fusion [PSF]) were assessed with Xray and gait analysis before and one year after surgery. Kinematic, electromyographic (EMG), mechanical and energetic measurements were recorded.
Results: Mean Cobb angle correction was around 50% whatever the surgical procedure. Gait study demonstrated the same results in both surgical procedures. One year after surgery, there was a significant increase in pelvis and hips frontal motion. Wtot increased by 6%, but was still lower than Wtot in normal population. C remained excessive and was still correlated with prolonged LPMTA.
Discussion: Increase of Wtot was mainly due to increase in external work and could be explained by improvement in pelvis and hips motion, resulting in increase of Centre Of body Mass vertical displacement. Excessive C could be explained by persistence of prolonged LPMTA.
Conclusion: The persistence of excessive C, prolonged LPMTA and decreased Wtot after surgery leads us to hypothesize a possible neuromuscular aetiology for AIS.
Significance: This study raises questions about a possible neuromuscular aetiology in AIS.