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 6

Adjacent segment disease in the fusion alone groups in these cited manuscripts.

	Patients; numbers	Mean; age (Y/O)	Pre-op status; at index level	Radiographic ASD; at index level	Symptomatic ASD; at index level	Revision surgery; for ASD	Radiographic ASD at; supra-adjacent level
Formica et al. [13], 2015	No comparative fusion group in the manuscript
Putzier et al. [14], 2010	25	44.6	(1) Asymptomatic bur radiographic DD; (Modic grade I)	6	1	1	0
Imagama et al. [15], 2009	35	64	(1) No instability; (2) Pfirrmann Gr. II–IV; (3) None, mild, or moderate spinal stenosis	35	No	No	14
Lu et al. [16], 2015	42	59	(1) DH ≦ 50% with/without segmental F/E mobility; (2) No segmental F/E mobility and the status of disc was suitable	20	9	3	NA
Lee et al. [17], 2013	50	65.9	(1) Pfirrmann Gr. II-III; (2) MRI: facet degeneration or effusion; (3) Mild to moderate spinal or foraminal stenosis	24	7^+	7	NA
Korovessis et al. [18], 2009	21	64	(1) UCLA Gr. I or II (no listhesis or lytic lesion); (2) Degenerative (listhesis, spinal stenosis, loss of segmental lordosis); (3) 2 to 4 vertebral fusions	6	3^+	3	6

DH: disc height; F/E: flexion/extension. The authors only mentioned numbers of revision surgeries for symptomatic ASD but did not mention numbers of symptomatic ASD. The numbers of symptomatic ASD might be underestimated.