Table 2.

Fusion rates by numbers of levels^*.

		Frozen				Glycerol-preserved				Frozen versus glycerol statistically similar?
		Total levels	Fused grafts	Not fused	% of fused levels	Total levels	Fused grafts	Not fused	% of fused levels
Three months	Total	70	29	41	41.4%	64	29	35	45.3%	Yes (P = 0.6535)
	1 level	12	6	6	50.0%	4	1	3	25.0%	Yes (P = 0.4283)
	2 levels	40	17	23	42.5%	32	13	19	40.6%	Yes (P = 0.8748)
	3 levels	18	6	12	33.3%	24	11	13	45.8%	Yes (P = 0.4235)
	4 levels	0	0	0	—	4	4	0	100%	—
12 months	Total	45	45	0	100.0%	41	41	0	100%	Yes (P > 0.999)
	1 level	8	8	0	100.0%	2	2	0	100%	Yes (P > 0.999)
	2 levels	25	25	0	100.0%	17	17	0	100%	Yes (P > 0.999)
	3 levels	12	12	0	100.0%	18	18	0	100%	Yes (P > 0.999)
	4 levels	0	0	0	—	4	4	0	100%	—

^*Note that 2-level patients had both glycerol-preserved and frozen grafts. The results from those patients were counted as 1 level in each 2-level treated group.