Update on pathology and surgical treatment for adult spinal deformity

Update on surgical strategies for ASD: We classified ASD into following 5 types in terms of curve patterns, global balance, and curve flexibility: Type 1, well-balanced scoliosis with flexible kyphosis is indicated for corrective posterior spinal fusion (PSF) without any release procedures; Type 2, poor-balanced scoliosis with flexible kyphosis is well corrected by aggressive intervertebral release with PSF; Type 3, fixed sagittal imbalance without coronal deformity is candidate for pedicle subtraction osteotomy; Type 4, fixed sagittal imbalance with coronal deformity is indicated for vertebral column resection; and Type 5, severe scoliosis without marked global sagittal malalignment can be treated by corrective anterior spinal fusion. Minimally invasive lateral access surgery can be solution for reduction of surgical morbidity.