Fig. 4

Representative cases. Sagittal preoperative radiographs (a-1, 2, 3) showing increased Ext ROM (20.3°) in a 65-year-old man who underwent laminoplasty of C4–7; no significant LCL was observed 18 months after surgery (a-2, a-4: pre CL 20.1° vs. post CL 24.9°). Sagittal preoperative radiographs (b-1, 2, 3) showing low Ext ROM (8.2°) and Flex ROM (29°) in a 48-year-old man who underwent laminoplasty of C3–7; mild LCL was observed 16 months after surgery (b-2, b-4: pre CL 16.2° vs. post CL 8.6°). Sagittal preoperative radiographs (c-1, 2, 3) showing low Ext ROM (3.1°) and increased Flex ROM (38.3°) in a 55-year-old man who underwent laminoplasty of C4–6; severe LCL was observed 24 months after surgery (c-2, c-4: pre CL 15.4° vs. post CL -7.6°). CL, cervical lordosis; LCL, loss of cervical lordosis; Flex ROM, cervical spine range of flexion; Ext ROM, cervical spine range of extension