Table 1.

Anatomical lumbar changes following use of the iO-Flex^® system and of hemilaminotomy with foraminotomy in nondiseased cadaveric lumbar specimens

Variable, mean ± SD	iO-Flex system (n = 24)			Hemilaminotomy with foraminotomy (n = 24)			P§
	Pre	Post	Δ	Pre	Post	Δ
Spinal canal, cm2
Laminar area removed	−	0.47 ± 0.45	−	−	0.86 ± 0.37	−	<0.01
Bone canal area	2.01 ± 0.56	2.23 ± 0.58	0.22*	2.05 ± 0.60	2.47 ± 0.65	0.43*	<0.001
Soft tissue canal area	1.17 ± 0.38	1.72 ± 0.49	0.55*	1.17 ± 0.40	1.83 ± 0.53	0.66*	0.16
Ligamentum flavum area	0.47 ± 0.15	0.10 ± 0.17	−0.37*	0.46 ± 0.15	0.08 ± 0.18	−0.38*	0.94
Facet morphology
Joint cross-sectional area, cm2	4.15 ± 1.08	4.04 ± 1.08	−0.11†	4.05 ± 1.21	3.75 ± 1.25	−0.30*	<0.01
Facet area, cm2	1.56 ± 0.34	1.34 ± 0.35	−0.22‡	1.60 ± 0.43	1.41 ± 0.38	−0.18*	0.94
Facet width, cm	1.70 ± 0.28	1.65 ± 0.27	−0.05†	1.69 ± 0.31	1.52 ± 0.30	−0.17*	<0.01
Lateral recess
Lateral recess diameter, cm	0.52 ± 0.17	0.68 ± 0.23	0.17*	0.51 ± 0.18	0.61 ± 0.20	0.10†	0.14
Foramen
Foraminal area, cm2	1.51 ± 0.38	1.58 ± 0.36	0.07*	1.49 ± 0.37	1.53 ± 0.39	0.04‡	0.09
Foraminal width, cm	0.83 ± 0.19	0.92 ± 0.17	0.09*	0.81 ± 0.21	0.84 ± 0.21	0.04‡	0.06

Notes: Within-group significance value:

^*P < 0.001;

^†P < 0.01;

^‡P < 0.05.

^§Between-group significance value.