Table 5.

The top 10 co-occurrence keywords and their centralities in five-yearly analysis.

Ranking	2002–2006			2007–2011
	Keyword	Frequency	Centrality	Keyword	Frequency	Centrality
1	Spinal cord stimulation	92	0.91	Spinal cord stimulation	180	0.82
2	Chronic pain	36	0.15	Neuropathic pain	71	0.21
3	Electrical stimulation	27	0.13	Back surgery syndrome	43	0.04
4	Neuropathic pain	22	0.13	Chronic pain	42	0.06
5	Pain	21	0.08	pain	37	0.08
6	Management	21	0.07	Management	35	0.08
7	Experience	20	0.05	Experience	32	0.03
8	Dorsal column stimulation	20	0.07	Mechanism	32	0.1
9	Mechanism	19	0.06	Electrical stimulation	27	0.06
10	Back surgery syndrome	18	0.03	Dorsal column Stimulation	23	0.04
Ranking	2012–2017			2018–2023
	Keyword	Frequency	Centrality	Keyword	Frequency	Centrality
1	Spinal cord stimulation	271	0.61	Spinal cord stimulation	440	0.56
2	Neuropathic pain	155	0.34	Neuropathic pain	179	0.22
3	Chronic pain	97	0.11	Chronic pain	173	0.13
4	Back surgery syndrome	90	0.13	Multicenter	102	0.04
5	Failed back surgery syndrome	61	0.05	Management	92	0.07
6	Management	50	0.04	Pain	88	0.05
7	Pain	45	0.05	10 khz high frequency	81	0.03
8	Randomized controlled trial	44	0.03	Failed back surgery syndrome	78	0.04
9	Follow up	41	0.03	Mechanism	76	0.06
10	Mechanism	37	0.04	Back surgery syndrome	76	0.05