PEEK versus Silicon Interspinous Spacer for Reduction of Supradjacent Segment Degeneration following Decompression and Short-Segment Instrumentation for Degenerative Lumbar Spinal Stenosis

Table 7

Changes of radiographic parameters preoperatively till the last follow-up in Groups R, S, and C (paired t-test).

Group	Preop	Postop	Pre/Post	Postop-2	F-up	Postop-2/F-up
		6 mon	P-value	2 years	max	P-value
	Lordosis T12-S1(Cobb degrees)
R	48±11	43±8	0.15	43±7	44±8	0.12
S	47±13	49±11	0.49	48±11	48±13	0.64
C	39±16	41±13	0.58	40±12	42±12	0.32
	SL (Cobb degrees)
R	18±8	23±6	0.082	22±6	23±6	0.78
S	22±12	23±10	0.67	23±9	23±10	0.49
C	22±16	26±8	0.27	27±6	26±9	0.65
	SS (Cobb degrees)
R	31±8	34±7	0.015	33±8	34±6	0.30
S	33±10	31±7	0.46	30±6	31±7	0.82
C	27±10	31±10	0.054	30±12	31±10	0.63
	PDH (Cobb degrees)
R	4±1	5±2	0.38	5±2	5±2	0.72
S	6±2	7±2	0.38	7±2	6±1	0.72
C	4±2	4±2	0.23	4±2	4±2	0.50
	SVA (mm)
R	11±19	9±18	0.37	9±15	10±17	0.54
S	12±18	9±16	0.54	8±14	9±17	0.45
C	14±18	12±15	0.91	13±16	12±15	0.33
	ADH (Cobb degrees)
R	6±2	7±2	0.34	7±3	6±2	0.06
S	10±2	12±1	0.34	11±3	11±2	0.15
C	7±3	7±2	0.71	6±3	6±2	0.039
	PT (Cobb degrees)
R	33±2	25±10	0.52	24±11	26±9	0.08
S	23±7	22±9	0.17	23±9	24±8	0.17
C	28±7	29±6	0.18	28±7	30±6	0.73