Perioperative Low-Dose Ketamine for Postoperative Pain Management in Spine Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Table 1

Characteristics of the included studies.

Author	Year	Group	Sample size	Age (years)			Sex (M/F)	Weight (kg)			Mode	Bolus (mg kg^−1)	Infusion (μg kg^−1 min^−1)	Dose in IV-PCA(mg ml^−1)	Timing	Postoperative Opioid	Control
Javery	1996	Ketamine	22	37.3	±	9.9	18/4	78.2	±	13.1	IV-PCA			1.0	Postoperative	Morphine	Basic
		Control	20	39.5	±	7.2	18/2	83.9	±	10.7
Sahin	2004	Ketamine	17	46.5	±	7.3	9/8	80.4	±	16.1	B	0.5			Intraoperative	Morphine	Saline
		Control	14	46.1	±	13.3	8/6	78.7	±	13.2
Aveline	2006	Ketamine	23	48.3	±	12.3	11/12	74.2	±	6.3	B	0.15			Intraoperative	Morphine	Basic
		Control	23	44.4	±	11.2	10/13	68.4	±	12.8
Engelhardt	2008	Ketamine	16	14.8	±	1.7	2/14	59.3	±	16.5	B+ivgtt	0.5	4.0		Intraoperative	Morphine	Saline
		Control	18	15.5	±	1.2	3/15	56.5	±	10.4
Moustafa	2008	Ketamine	16	13.1	±	5.08	7/9	39.7	±	8.63	ivgtt		1.0		Intraoperative	Morphine	Basic
		Control	16	12.8	±	6.07	6/10	34.6	±	9.68
Urban	2008	Ketamine	12	53	±	12		80	±	19	B+ivgtt	0.2	0.03		Intraoperative; Postoperative	Hydromorphone	Saline
		Control	12	48	±	9		78	±	19
Hadi	2009	Ketamine	20	22	±	2	7/13	55	±	15	ivgtt		1.0		Intraoperative	Morphine	Basic
		Control	20	21	±	2	8/12	54	±	13
Hadi	2010	Ketamine	15	56.1	±	10.5	7/8	66	±	13	ivgtt		1.0		Intraoperative	Morphine	Saline
		Control	15	53.5	±	10.2	3/12	68	±	12
Loftus	2010	Ketamine	52	51.7	±	14.2	33/19	95.4	±	17.7	B+ivgtt	0.5	10.0		Intraoperative	Morphine	Saline
		Control	50	51.4	±	14.4	28/22	89.3	±	23.8
Subramaniam	2011	Ketamine	15	57.2	±	12.2	8/7	86.2	±	24.4	B+ivgtt	0.15	2.0		Intraoperative; Postoperative	Hydromorphone	Saline
		Control	15	56.5	±	13.6	7/8	81.4	±	19.2
Abrishamkar	2012	Ketamine	22	49	±	1.32	5/18				ivgtt		8.33		Postoperative	Morphine	Basic
		Control	23	45	±	1.64	10/12
Pacreu	2012	Ketamine	10	52.9	±	12.6	3/7	69.5	±	7.2	B+ivgtt+IV-PCA	0.5	2.5	0.5	Intraoperative; Postoperative	Methadone	Saline
		Control	10	61.3	±	11.7	3/7	75.9	±	9.8
Yeom	2012	Ketamine	20	61.0	±	10.0	5/15	59.1	±	13.5	B+ivgtt	0.2	0.5		Intraoperative; Postoperative	Fentanyl	Saline
		Control	20	64.5	±	11.5	7/13	64.8	±	10.6
Hadi	2013	Ketamine	30	55	±	2.5	13/17	70	±	2.5	ivgtt		1.0		Intraoperative; Postoperative	Morphine	Saline
		Control	15	51	±	2.5	8/7	71	±	2.6
Kim	2013	Ketamine	35	56	±	9.5	15/20	63.4	±	10.5	B+ivgtt	0.5	1.0-2.0		Intraoperative; Postoperative	Fentanyl	Saline
		Control	17	56	±	13	9/8	66	±	13
Song	2013	Ketamine	24	52.3	±	8.8	0/24	59	±	7	B+ivgtt	0.3	0.04		Intraoperative; Postoperative	Fentanyl	Saline
		Control	25	53.8	±	7.8	0/25	60	±	10
Pestieau	2014	Ketamine	29	14.3	±	1.8	5/24	60	±	18	B+ivgtt	0.5	0.1-0.2		Intraoperative; Postoperative	Morphine	Saline
		Control	21	14.5	±	1.5	7/14	59	±	14
Minoshima	2015	Ketamine	17	15	±	2	1/16	45	±	6	B+ivgtt	0.5	2.0		Intraoperative; Postoperative	Morphine	Saline
		Control	19	14	±	2	0/19	46	±	4
Garg	2016	Ketamine	22	36.5	±	13.4	13/9	61.5	±	14.6	B+ivgtt	0.25	4.2		Postoperative	Morphine	Saline
		Control	22	36.3	±	14.3	16/6	65.3	±	15.5
Mitra	2017	Ketamine	14	33.9	±	17.2	7/7	56.4	±	10.1	B+ivgtt	0.5	4.2		Intraoperative	Fentanyl	Saline
		Control	14	33.5	±	15.2	6/8	57.9	±	11.3
Nielsen	2017	Ketamine	74	57	±	14	28/46	77	±	14	B+ivgtt	0.5	4.2		Intraoperative	Morphine	Saline
		Control	73	55	±	13	21/52	78	±	18
Perello ́	2017	Ketamine	21	14.3	±	1.9	5/16	54.3	±	10.8	B+ivgtt	0.5	2.0		Intraoperative; Postoperative	Morphine	Saline
		Control	23	14.3	±	1.8	6/17	57.6	±	12.6
Boenigk	2018	Ketamine	49	54.5	±	13.4	24/25	78.5	±	7.2	B+ivgtt	0.2	2		Postoperative	Hydromorphone	Saline
		Control	62	55.7	±	13.2	29/33	85.4	±	11.5
Czarnetzki	2019	Ketamine	80	65.8	±	13.8	39/41	79.8	±	4.3	B+ivgtt	0.25	1.67-4.17		Intraoperative; Postoperative	Morphine	Saline
		Control	80	65.6	±	12.6	42/38	79.7	±	3.4
Brinck	2020	Ketamine	127	54.2	±	13.2	40/87	76	±	14	B+ivgtt	0.5	2-10		Intraoperative	Oxycodone	Saline
		Control	62	55.5	±	12	26/36	79	±	15
Ricciardelli	2020	Ketamine	24	13.4	±	1.7	2/22	60.9	±	17.4	B+ivgtt	0.5	3.33		Intraoperative; Postoperative	Morphine	Saline
		Control	25	14.7	±	2.2	8/17	61.6	±	14.2
Andleeb	2021	Ketamine	30	43.8	±	14.6	15/15	57.4	±	11.4	ivgtt		8.33		Intraoperative	Morphine	Saline
		Control	30	39.8	±	14.1	14/16	58	±	12.7
Brinck	2021	Ketamine	75	60	±	13.5	41/34	77.1	±	14.5	IV-PCA			0.25-0.75	Postoperative	Oxycodone	Saline
		Control	25	56	±	11	14/11	77.7	±	15.6
Murphy	2021	Ketamine	66	59.3	±	16.4	32/34	64	±	11	ivgtt		1.67-5.00		Intraoperative; Postoperative	Hydromorphone	Saline
		Control	61	65.3	±	10.6	27/34	62	±	11
Nikoubakht	2021	Ketamine	29	52.8	±	12.2	17/12				ivgtt		1.67		Intraoperative	Morphine	Saline
		Control	29	53.8	±	13.9	18/11

B indicates intravenous bolus; ivgtt, intravenously guttae; IV-PCA, intravenous patient-controlled analgesia.