Table 3.

The intervertebral space and intervertebral foramen height compared to between two groups (x ± s) (mm)

Groups	Intervertebral space height			Intervertebral foramen height
	Pre-	Post-	Follow-up	Pre-	Post-	Follow-up
PILF	6.8 ± 2.3	11.6 ± 1.5*	11.2 ± 1.2	14.2 ± 1.7	18.7 ± 1.8*	18.1 ± 1.8
TILF	6.7 ± 1.7	11.4 ± 1.6*	11.3 ± 1.4**	14.1 ± 1.8	18.5 ± 1.6*	18.2 ± 1.7**

* Compared to the pre-operation P < 0.05; ** Compared to PILF P > 0.05