Table 1.

Factors to consider in selective fusion of thoracic curves

Category		Criteria	Note
Candidates		Lenke 1C, 2C, 3C, 4C
Clinical parameters		Lifestyle and activity level
		Thoracic rotational prominence > lumbar prominence
		Soft tissue flexibility : thumb abduction test
Radiographic parameters
	Coronal plane ratio criteria	AVT thoracic >1.2	Possible if AVT criteria only
		AVT thoracolumbar/lumbar >1.2	Better if 2 or 3 criteria met
		AVR thoracic >1.2
		AVR thoracolumbar/lumbar >1.2
		Thoracic Cobb angle >1.2
		Thoracolumbar/lumbar Cobb angle >1.2
	Sagittal plane criteria	Thoracolumbar (T10–L2) kyphosis <10°
		Sagittal disc angle below LIV : lordosis
	Skeletal maturity	Triradiate cartilage : closed
	Additional criteria	TL/L side bending <25°	Possible if TL/L side bending >25° if more criteria are met
		TL/L curve <60°
		CSL touches thoracic LEV or below

AVT : apical vertebral translation, AVR : apical vertebral rotation, LIV : lower instrumented vertebra, TL/L : thoracolumbar/lumbar, CSL : central sacral vertical line, LEV : lower end vertebrae