Table 1:

Clinical and radiographic characteristics of patients in the 2 groups

Group DGroup NDP
Number4433
Age (years)14.0 ± 2.0 (10–18)14.6 ± 1.9 (10–18)NS
Sex (male/female)26/1820/13NSa
Extent of tonsillar descentNSa
    Grade I2517
    Grade II1615
    Grade III31
Syrinx locationNSb
    Proximal levelC2–C5C2–C6
    Distal levelC6–T4C6–T3
Syrinx/cord ratio0.70 ± 0.10 (0.51–0.88)0.39 ± 0.09 (0.19–0.50)<.001
Taper ratio (mm/level)
    C1–C7−0.34 ± 0.54 (−2.03–0.81)−0.73 ± 0.57 (−1.88–0.98).001c
    C1–C4−0.98 ± 0.87 (−2.47–1.70)−1.61 ± 0.98 (−3.66–0.85).004c
    C4–C70.24 ± 0.50 (−0.85–1.65)−0.04 ± 0.54 (−0.97–1.36).033c

  • Note:—NS indicates statistical nonsignificance.

  • ↵a χ2 test.

  • ↵b Fisher exact test.

  • ↵c Kruskal–Wallis test or otherwise Student t test.