Could the Topping-Off Technique Be the Preventive Strategy against Adjacent Segment Disease after Pedicle Screw-Based Fusion in Lumbar Degenerative Diseases? A Systematic Review

Table 4

Data in the hybrid stabilization device, interspinous process device, and fusion groups.

	Hybrid stabilization device	Interspinous process device	Fusion	p value
Numbers of patients	95	98	173	NA
Age (y/o)^+	62.7	64.9	60.5	NA
Male/female	NA	NA	NA	NA
Numbers of fused vertebrae	2	3.4	2.45	NA
Follow-up (months)	42.8	47.2	50.4	NA
Adjacent segment disease (ASD)
Symptomatic ASD at index level	0	5 (5.1%)	20^++ (11.6%)	0.003
Radiographic ASD at index level	12 (12.6%)	10 (10.2%)	91 (52.6%)	<0.001
Symptomatic ASD at supra-adjacent level	0	0	0	—
Radiographic ASD at supra-adjacent level	7 (10.5%)	1 (1%)	20/81 (24.7%)	<0.001
Revision surgery for ASD	0	3 (3%)	14 (8.1%)	0.008

The bold numbers in the p values indicated statistical significance. NA indicates not available.
The authors did not exclude those who lost follow-up in the demographic results. The mean age was just estimated.
Two papers only mentioned numbers of revision surgeries for symptomatic ASD but did not mention numbers of symptomatic ASD. (The result might be underestimated.)
Only 3 cited manuscripts reported their results.