Table 1.

Indications.

Groups related		Compendium	Examples
Drug	Refractory to other analgesics	Chronic severe pain	Advanced cancer pain [6,40,55]
			diabetic peripheral neuropathy (DPN) [72,73]
			HIV [73], etc.
		Neuropathic pain	Spinal cord injury [77]
Administration	Refractory to other administration methods	Applicative when other conservative or minimally invasive methods failed or experiencing untreatable side-effects	Cancer pain [40,55,65]
			Spinal cord injury [80]
			Abdominal/pelvic pain [[77], [78], [79]]
			Extremity pain [79]
			Trunk pain [79], etc.