Table 1.

General overview of included clinical studies and human case reports examining the effect of cell transplantation for low back pain alleviation or disc degeneration repair.

Author	Year	Ref	FU (y)	Site	Mode	Product	Cell density	Volume and carrier	n	Control(s)	n	Efficacy	Safety	Type
Yoshikawa	2010	[36]	2	ID	Autologous	BM-MSC	Unclear	0.54mL collagen sponge	2	-	-	✔	✔	Mesenchymal stromal cells
Orozco	2011	[37]	1	ID	Autologous	BM-MSC	10×106/mL	0.5-1.5mL saline	10	-	-	✔	✔
Centeno	2017	[38,39]	6	ID*	Autologous	BM-MSC	23×106/disc	1-3mL 10-20% PL/PBS	33	-	-	✔	✔
Noriega	2021	[40], [41], [42]	3.5	ID	Allogenic	BM-MSC	12.5×106/mL	2mL saline	Unclear	Muscle anesthetic	Unclear	✔	✔
Papadimitriou	2021	[43,44]	2	ID	Autologous	BM-MSC	1×106/mL	1mL 20% serum/F12	10	-	-	✔	✔
Amirdelfan	2021	[45,46]	3	ID	Allogenic	MPC	High: 18×106/disc Low: 6×106/disc	2mL HA	60	HA (Vehicle) Saline (Placebo)	20 20	✔	✔
Jung	2013	[47]	<0.5	IV	Autologous	AD-MSC	Unspecified	Unspecified	3	-	-	✘	✔
Piccirilli	2017	[48]	1	ID	Autologous	AD-MSC	Unspecified	1mL solution	2	-	-	✘	✔
Kumar	2017	[49]	1	ID	Autologous	AD-MSC	High: 20×106/disc Low: 10×106/disc	2mL HA	5 5	-	-	✔	✔
Bates	2022	[50]	1	ID	Autologous	AD-MSC	10×106/disc	1mL saline	9	-	-	✔	✔
Zhang	2022	[51]	2	ID	Autologous	AD-MSC	High: 20×106/disc Mid: 10×106/disc Low: 5×106/disc	2mL HA	25 25 25	Saline (Placebo)	25	✘	✘
Pang	2014	[52]	2	ID	Allogenic	UC-MSC	10×106/mL	1mL solution	2	-	-	✔	✔
Meisel	2006	[53], [54], [55]	2	ID	Autologous	IVD-C	Unspecified	Unspecified	12	Discectomy-only	16	✔	✘	Chondrogenic cells
Mochida	2015	[56]	3	ID	Autologous	NPC	∼1.5×106	0.7 mL saline	9	-	-	✔	✔
Tschugg	2017	[57,58]	<0.5	ID	Autologous	IVD-C	Unclear	PEG + serum + media	12	Discectomy +  HA (Vehicle)	12	✘	✔
Schwan	2017	[59]	n.a.	ID	Autologous	IVD-C	Unspecified	Saline OR `polymerizing-scaffold`	10	Discectomy-only	10	✘	✔
Beall	2020	[60]	1	ID	Allogenic	NPC	Unclear	1.75mL NP tissue	16	Saline (Placebo) Conservative care	4 4	✔	✔
Hunter	2022	[61,62]	1	ID	Allogenic	NPC	Unclear	1.75mL NP tissue	140	Saline (Placebo) Conservative care	39 39	✔	✔
Foley	2022	[63]	1.5	ID	Allogenic	NPC	High: 9×106/disc Low: 3×106/disc	1mL HA	20 20	Saline (Placebo) HA (Vehicle)	10 10	✔	✔
Xuan	2022	[64]	6	ID	Autologous	IVD-C	4-7×106/disc	1-3mL saline	18	Discectomy-only	22	✔	✔
Coric	2013	[65]	1	ID	Allogenic	AC	10×106/mL	1-2mL fibrin	15	-	-	✔	✔
Comella	2017	[66]	1	ID	Autologous	SVF	30-60×106/1-3 disc	1mL PRP	15	-	-	✔	✔	Mixture of cells
Pettine	2017	[67], [68], [69]	3	ID	Autologous	BMC	130×106/mL	2-3mL solution	26	-	-	✔	✔
Wolff	2020	[70]	1	ID	Autologous	BMC	Unspecified	3mL solution	33	-	-	✔	✔
Ramos	2020	[71]	1	ID	Autologous	BMC	Unspecified	Unspecified mL PRP	1	-	-	✘	✔
El-Kadiry	2021	[72]	1	ID	Autologous	BMC	Unspecified	1-6mL solution	13	-	-	✔	✔
Jerome	2021	[73]	<0.5	ID	Autologous	BMC	Unspecified	Unspecified	3	-	-	✘	✔
Xu	2021	[74]	2	ID	Autologous	BMA	Unspecified	∼1.25mL gelatin sponges	15	Discectomy-only Discectomy + AF suture	15 15	✔	✔
Subach	2011	[75]	1	ID	Autologous	BMA + AT + Plasma	Unspecified	3mL solution	1	-	-	✘	✔
Haufe	2005	[76]	1	ID	Autologous	HSC	Unspecified	Unspecified	10	-	-	✔	✘

Efficacy and Safety columns represent whether outcomes are reported presenting overall improvements in pain, disability, quality of life, or image modalities or the presence of (serious) adverse events following cell therapy respectively; ✔: reported, ✘: not reported. * MSC was transplanted intradiscally, treatment was complemented with epidural injection of PL. Abbreviations: AC – Articular cartilage derived cells, AD-MSC- Adipose derived mesenchymal cells, AF – Annulus fibrosis, AT – Adipose tissue, BMA – Bone marrow aspirate, BMC – Bone marrow concentrate, BM-MSC - Bone marrow derived mesenchymal stromal cells, FU – (maximal) Follow up, HA – Hyaluronic acid, HSC – Hematopoietic stem cells, ID – Intradiscal, IV – Intravenous, IVD-C – Intervertebral disc derived cells, MPC - Mesenchymal precursor cells, N.A. – Not applicable, NP – Nucleus pulposus, NPC – Nucleus pulposus cells, PBS – Phosphate buffered saline, PEG - Polyethylene glycol, PL – Platelet lysate, PRP – Platelet rich plasma, REF – Reference, and SVF – Stromal vascular fraction, and UC-MSC – Umbilical cord mesenchymal stromal cells.