Degenerative adult scoliosis results from age related changes leading to segmental instability, deformity and stenosis. Although the etiology is unclear, degenerative adult scoliosis is associated with progressive and asymmetric degeneration of the disc and facet joints, which typically lead to stenosis. By virtue of the narrowed spinal canal associated with the degeneration these patients frequently develop back pain, as well as leg pain, weakness, and numbness. With an aging population in the USA and an increased attention to quality of life versus cost issues in the current healthcare environment, degenerative adult scoliosis has become a considerable healthcare concern.
Patients with scoliosis demonstrate an altered gait pattern. Such differences include decreased step length and reduced range of motion in the upper and lower extremities, asymmetry of trunk rotation and ground reaction force in three-dimensions. Mahaudens et al. found a decrease in the muscular mechanical work associated with an increase of energy cost and a decrease in the muscular efficiency in a scoliosis population compared to healthy controls. Furthermore, scoliosis patients exert 30% more physical effort than healthy subjects to ensure habitual locomotion, and this additional effort requires a reciprocal increase of oxygen consumption. This altered gait pattern demonstrated by subjects with scoliosis may be due to changes in global postural control strategies caused by spinal deformity.
Previous research showed that scoliosis patients do not have impaired postural balance when compared to healthy controls, while several others did find an effect of scoliosis on postural balance. This discrepancy in findings may be due to differences in curve characteristics included and their effects on postural balance, curve types (single or double), number of different curve types, location of curves (thoracic and lumbar), and/or Cobb angles. Furthermore, Schimmel et al. found that postural balance one year after surgery did not improve as a result of the better spinal alignment, neither did the reduced range of trunk motion inherent to fusion negatively affect postural balance.
While medicinal interventions may assist with some of the associated co-morbid conditions, surgical interventions may be indicated for those patients with intractable and debilitating low back and leg pain. These surgeries have proven to be extremely successful in a majority of patients. The surgeries may involve decompression and instrumentation to stabilize the spine to achieve arthrodesis.
Surgical intervention may provide pain relief and improvement in function but one area of significant clinical interest is the restoration/improvement in gait and functional balance. Based on the investigators knowledge, there is limited literature on biomechanics and neuromuscular control of the lower extremities and spine as assessed by objective gait analysis and balance strategies in adult degenerative scoliosis patients, pre and post surgical intervention. The purpose of this study is to determine the impact of spinal deformity on the biomechanics and neuromuscular control of the lower and upper extremities, and also investigate the impact of surgery on these functions as evaluated by gait and balance analyses using dynamic Electromyograph (EMG), video motion capture and force plate analysis and also to compare these patients with healthy controls to better evaluate the extent of limitations before and after surgery.
