The effect of positive sagittal spine balance and reconstruction surgery on standing balance

Positive sagittal spine balance (PSSB) may adversely influence standing balance in individuals with degenerative spine diseases. PSSB is often corrected with the help of spinal reconstructive surgeries involving multiple vertebral units.

This study investigated the effect of PSSB and reconstructive surgery on postural sway as a measure of standing balance. The secondary goal of this study was to investigate the effect of reconstructive surgery on lower limb kinematics.

Subjects who underwent spinal reconstructive surgery for correction of PSSB greater than or equal to 7 cm participated in this study. Postural sway data while standing quietly for 20 s on a force platform were analyzed pre-operatively, 6-12 months and 24 months post-operatively.

Reconstructive surgery was successful in correcting PSSB in all individuals. There was a moderate correlation between PSSB and postural sway in the anterior-posterior (AP) direction before surgery (r = 0.58) and at 6-12 months post-surgery (r = 0.63). Reconstructive surgery had a significant main effect on postural sway in both the anterior-posterior (p < 0.009, F = 7.01) and medial-lateral directions (p < 0, F = 12.30). Reconstructive surgery also had a significant main effect on standing hip (p < 0, F = 17.01) and knee flexion (p < 0, F = 32.23).

These results reveal that PSSB in persons with degenerative spinal conditions compromised postural balance, which improved after reconstructive surgery. Additionally, persons with PSSB adopted a crouch posture, which resolved after reconstructive surgery.