Fig. 4From: Biomechanical role of osteoporosis affects the incidence of adjacent segment disease after percutaneous transforaminal endoscopic discectomya–d Biomechanical changes in different models. F, Flexion; E, extension; L, left lateral bending; R, right lateral bending; A, Axial rotation. Model 1: contact model. Model 2: PTED model with normal bone mineral density. Model 3: PTED model with osteoporosisBack to article page