Table 2.

Mean ODI scores preoperatively, at 3 months, and 4–7 years postoperatively

	Group		t	P
	1	2
Preop	31.14 ± 9.27	29.62 ± 8.19	0.87	0.387
Early	14.22 ± 9.88	12.22 ± 6.46	1.2	0.234
Late	14.02 ± 9.27a	12.40 ± 6.30b	1.02	0.309
F	127	136
P	0.0001	0.0001

^aP > 0.05 compared with early follow-up in Group 1

^bP > 0.05 compared with early follow-up in Group 2