Chien, AndyAndyChienDAR-MING LAISHWU-FEN WANGCheng, Chih-HsiuChih-HsiuChengWEI-LI HSUWang, Jaw-LinJaw-LinWang2020-06-302020-06-3020150940-6719https://www.scopus.com/inward/record.uri?eid=2-s2.0-84947934160&doi=10.1007%2fs00586-015-3900-7&partnerID=40&md5=5ed0dfebb712111a5c16e9a72f433164https://scholars.lib.ntu.edu.tw/handle/123456789/506583Purpose: To determine and compare the biomechanical effects of single- and two-level anterior cervical decompression and fusion (ACDF) on the re-distribution of the segmental contribution to total cervical range of motion (ROM) in a prospective longitudinal design. Methods: Fifty-one patients undergoing either a single- or two-level ACDF due to cervical disc disease were recruited. Functional radiographs were taken preoperatively and then at 3, 6 and 12-month follow-ups. Global ROM of C2–C7, ROM of the treated functional spinal unit (FSU) and the superior and inferior segmental ROMs were then measured. The relative contribution from the FSU and each of the adjacent segments to total cervical ROM were compared pre- and post-operatively within and between the two groups at each of the time points. Results: Single-level ACDF patients demonstrated a significantly greater total cervical ROM at 6 and 12?months compared with the two-level ACDF group (p?=?0.021 and 0.045, respectively). A significantly greater contribution from the FSU to the total ROM was found at 3?months in the two-level ACDF group (p?=?0.016), but the greater contribution shifted to the superior adjacent segment at 6 and 12?months (p?=?0.025 and 0.046). The two-level ACDF group did not demonstrate a significant difference at 3?months (p?=?0.087), but a significant increase in contribution was found at 6 and 12?months (p?<?0.01). Conclusions: Single-level ACDF maintains and restores a more physiological re-distribution of segmental contribution of ROM compared with two-level ACDF, which required longer time to achieve stable FSU immobilization and coupled with significantly increased superior segment contribution. ? 2015, Springer-Verlag Berlin Heidelberg.en[SDGs]SDG3adult; anterior cervical decompression and fusion; anterior spine fusion; Article; biomechanics; female; follow up; human; intervertebral disk disease; intervertebral diskectomy; longitudinal study; major clinical study; male; middle aged; outcome assessment; postoperative period; preoperative evaluation; priority journal; prospective study; range of motion; spinal cord decompression; surgical technique; cervical vertebra; decompression surgery; intervertebral diskectomy; joint characteristics and functions; procedures; radiography; spine fusion; surgery; Biomechanical Phenomena; Cervical Vertebrae; Decompression, Surgical; Diskectomy; Female; Humans; Longitudinal Studies; Male; Middle Aged; Prospective Studies; Range of Motion, Articular; Spinal Fusionjournal article10.1007/s00586-015-3900-7258609962-s2.0-84947934160