Table I.

Relationship between local anesthetic volume and diffusion level.

(Refs.)	Year	Experimental sample type	Local anesthetic	Capacity (one side)	Blocking site	Diffusion level	Capacity/number of segments
Tulgar and Senturk (50)	2018	Patient	Bupivacaine 0.25% + lidocaine 0.3%	30 ml	L4	T12-L4	6
Chung and Kim (51)	2018	Patient	5 ml 2% lidocaine and 15 ml contrast medium	20 ml	L4	L2-S1	4
De Lara González et al (47)	2019	Corpse	Contrast medium	20 ml	L4	L2-L5	5
Mantuani et al (52)	2019	Patient	20 ml of 1% lidocaine containing adrenaline	20 ml	L1	T10-L2	4
Celik et al (53)	2019	Patient	40 ml injection, including 20 ml bupivacaine, 10 ml lidocaine, 8.6 ml physiological saline, 40 mg/ml methylprednisolone, 1 ml, and 0.4 ml contrast agent	40 ml	L4	L1-S4	4.4
Ahiskalioglu et al (54)	2020	Patient	20 ml 0.5% bupivacaine, 10 ml 2% lidocaine, and 10 ml physiological saline	20 ml	L4	L2-L5	5
Breidenbach et al (55)	2023	Corpse	1 ml methylene blue and 19 ml 0.25% bupivacaine	20 ml	L4	L2-S1	4
Zhang et al (56)	2021	Patient	20 ml 0.4% ropivacaine	20 ml	L3	L1-L5	4
Yi-Han et al (21)	2022	Patient	20 ml 0.375% ropivacaine and 20 ml dexmedetomidine	20 ml	L3	L1-L5	4