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

Table 1

Patients with circumferential fusion presented per group and level of PLIF insertion.

Group	Segments fused
	L4/L5	L5/S1	No PLIF	Total
R	12	2	3	17
S	9	4	5	18
C	12	3	5	20
Total	33	9	13	55