A novel classification on degenerative thoracolumbar kyphosis based on sagittal spino-pelvic alignment: should the thoracolumbar segments be intervened?

Table 7 The characteristics and operation strategies for DTLK patients based on the classification

Classification	Classification basis	Features and risk factors	Biomechanical compensatory	Operation strategies
Type I	Small TLK Balance	Normal LL Normal PT Proper PI-LL	Compensation	Short-segment operation for LSS
Type II	Small TLK Imbalance	Lower LL Normal PT Mismatched PI-LL Severe OP	Partial	Multi-segment operation for LSS and mild imbalance (rigid fixation for case with severe OP)
Type III	Large TLK Balance	Normal LL Normal PT Proper PI-LL	Compensation	Multi-segment operation for LSS and kyphosis
Type IV	Large TLK Imbalance	Lower LL Retroversional PT Mismatched PI-LL	Decompensation	Long-segment operation for LSS, kyphosis and imbalance with I-IV osteotomy

Footnote: DTLK: degenerative thoracolumbar kyphosis; TLK: thoracolumbar kyphosis; SVA: sagittal vertical axis; SSA: Spino-sacral angle; TK: thoracic kyphosis; LL: lumbar lordosis; PT: pelvic tilt; OP: osteoporosis; LSS: lumbar stenosis syndrome

ISSN: 1749-799X