Table 1.

Relationships between baseline characteristics and changes of the cervical alignment

	Difference of cervical angle (P value)
Age at surgery	0.506
Gender	0.068
Preoperative syrinx width	0.192
Preoperative stage of tonsillar descent	0.097
Preoperative cervical lordotic angle	0.051
Difference ratio of syrinx width	0.016
Recovery rate	0.022

Difference ratio = (preoperative width − postoperative width)/preoperative width

Recovery rate by Japanese Orthopaedic Association scoring system = (postoperative score 2 preoperative score) × 100/(17 points − preoperative score). Relationships were assessed using Spearman rank correlation coefficients. The Mann–Whitney U test was used to analyze the differences between groups according to the extent of cerebellar tonsillar descent