Table 2.

Definition of pain response and protocol of follow-up.

Study	Definition of pain response	Time for comparison of pain relief	Terminating follow up if non-response
Levy et al[30] 2008	–	–	–
Ascunce et al[22] 2011	A decrease of ≥2 points in VAS compared with baseline without an increase in oral narcotic use	1 week and 1 months	Yes
Doi et al[18] 2013	NRS decreases to ≤3 points	1 week	Yes
Hao et al[23] 2014	NRS decreases to ≤3 points or a ≥30% reduction in NRS compared with baseline without an increase in pain medication use	3 days, 1 week, and 3 months	No
Levy et al[19] 2019	A decrease of ≥3 points in NRS or a ≥50% reduction compared with baseline	1, 2,3, 6, 9, and 12 months	No