Table 1.

Classification system for the lumbar spine as proposed by Lenke et al. [12]

LSM	Characteristics
A	CSVL falls between lumbar pedicles up to stable vertebra
	Must have thoracic apex
	If in doubt as to whether CSVL touches medial aspect of lumbar apical pedicle, choose type B
	Includes King type III, IV and V
B	CSVL falls between medial border of lumbar concave pedicle and lateral margin of apical vertebral body of bodies (if apex is a disc)
	Must have a thoracic apex
	If in doubt as to whether CSVL touches lateral margin of apical vertebral body/-ies, choose type B
	Includes King type II, III and V
C	CSVL falls medial to lateral aspect of lumbar apical vertebral body/-ies
	May have thoracic, thoracolumbar and/or lumbar apex
	If in doubt as to whether CSVL touches lateral margin of apical vertebral body/-ies, choose type B
	Includes King types I, II, V, double major, triple major thoracolumbar and lumbar curves

LSM lumbar spine modifier, CSVL central sacral vertical line