Table 1.

Selection criteria.

Inclusion criteria	Exclusion criteria
Male or female	Active oral anticoagulants or heparin therapy
18 years of age or older	Pregnancy
Refractory low back pain persisting for ≥ 6 months	Active cancer
Disc disease Grade II or more on Pfirrmann grading on T2 MRI with or without same level facet arthropathy	Systemic infection or skin infection over the puncture site
Willingness to voluntarily participate	Allergy to contrast agent
	Solid bone fusion preventing access to the disc
	Extrusions or sequestered disc fragments
	Previous spinal surgery
	Spondylolysis
	Spondylolisthesis: ≥ grade III