Comparisons of Clinical and Radiographic Outcomes.

JOA Japanese orthopedic association; NDI neck disability index; ROM, range of motion.Statistical significance was set at a PThe Kruskal-Wallis H test was used to investigate whether the statistical differences exist among the groups.*NDI scores at the final follow-up: P = 0.078 (2-level and 3-level groups); P = 0.000(2-level and 4-level groups); P = 0.002 (3-level and 4-level groups) by Nemenyi test.#ROM at the final follow-up: P = 0.005 (2-level and 3-level groups); P = 0.000(2-level and 4-level groups); P = 0.000 (3-level and 4-level groups) by Nemenyi test.▴Decrease rate of ROM: P = 0.005 (2-level and 3-level groups); P = 0.000(2-level and 4-level groups); P = 0.000 (3-level and 4-level groups) by Nemenyi test.