Table 3.

Utility of SCS (Epidural and Transcutaneous) in non-motor functions and spasticity in persons with SCI.

S. No.	Study	No. of Subjects	AIS; Neurological level	Place	Primary Outcome	Device	Stimulation Site	Stimulation parameters	Intervention, Follow Up and outcome	Concurrent Therapy
	ESCS-Genitourinary function
1	Katz et al., 1991 89	23	A-D; C4-T10	Richmond, VA, USA	Bladder function Postoperative changes in the lower urinary tract function were noted in 6 patients. Urodynamic parameters did not change significantly following implantation in the remaining 17 patients.	Electrode: Resume Model 7492 (Medtronic Inc. MN, USA) Stimulator: Not reported	T1 – tetraplegia T11 – 12 paraplegias	Frequency: 25–130 Hz Pulse Width: 180–450 μs Intensity: 0.25–10.5 V	Baseline assessment prior to ESCS implantation and follow up at 3 months and 1-year whilst ongoing ESCS use	None
2	Herrity AN. et al., 2021 90	10	6A, 4B; C3-T4	Louisville, KY, USA	Bladder function There was also a significant improvement change in bladder capacity (70 ± 83 mL) at post training and follow up 102 ± 120 mL	Electrode: Specify 5-6-5 Medtronic, MN, USA) Stimulator: Restore ADVANCED, Medtronic, MN, USA)	T11 – L1	Frequency: Not reported Pulse Width: Not reported Intensity: Not reported	Single testing session after 160 exercise sessions whilst ongoing ESCS use	Active recovery-based training
	ESCS- Pulmonary function and cough
1	DiMarco et al., 2020 91	10	NA; C2-T1	Cleveland, OH, USA	Cough Following daily use of SCS, mean inspiratory capacity improved.	Electrode: Not reported Stimulator: Not reported	T9 and T11	Frequency: 50 Hz Pulse width: 200 μs Intensity: 40V	5 testing sessions over 20 weeks whilst ongoing ESCS use	None
2	DiMarco et al., 2006 92	1	C; C5-6	Cleveland, OH, USA	Cough Combined T9+L1 stimulation increased airway pressure and expiratory flow rate to 132 cm H2O and 7.4 L/s respectively.	Electrode: Freehand Epimysial (NeuroControl Corp., OH, USA) Stimulator: Not reported	T9, T11, L1	Frequency: 40–53 Hz Pulse width: 150–200 μs Intensity: 40 V	Single assessment whilst ongoing ESCS use	None
3	DiMarco et al., 2009 93	9	-; C3–C6	Cleveland, OH, USA	Cough During stimulation, mean maximum airway pressure generation and peak airflow rates 137 ± 30 cm H2O and 8.6 ± 1.8 L/s respectively.	Electrode: Not reported Stimulator: Not reported	T9, T11, L1	Frequency: 2–105 Hz Pulse width: 16–800 μs Intensity: 10–40 V	Repeated assessments every 4–5 weeks for 28 weeks, follow up at 3 and then 6-month intervals whilst ongoing ESCE use	None
	TSCS- Pulmonary function and cough
1	Gad et a., 2020 94	1	A; C5	Los Angeles, CA, USA	Pulmonary function Improved breathing and coughing ability both during and after stimulation	TESCON (SpineX, Inc.)	Cathodal electrodes C5 – C6; Anodal electrodes bilateral shoulders	Pulse mode: Burst Frequency: 30 Hz, carrier 10 kHz Pulse width: 1 μs (biphasic) Intensity: 20 mA	30-min stimulation, session every 2 days minimum, 2 weeks (5 sessions) 1-week baseline, 60 min stimulation 5 sessions/week, 2 weeks (10 sessions), 1 week follow up	None
	ESCS- Autonomic and Cardiovascular function
1	Aslan SC. et al., 2018 95	7	4A,3B; C5-T4	Louisville, KY, USA	Autonomic In three patients with arterial hypotension, ESCS applied while supine and standing maintained blood pressure at 119/72 ± 7/14 mmHg compared to 70/45 ± 5/7 mmHg without ESCS.	Electrode: 5-6-5 Specify (Medtronic Inc. MN, USA) Stimulator: RestoreADVANCED (Medtronic Inc. MN, USA)	T11 – L1	Frequency: 2 Hz Pulse width: Not reported Intensity: Maximum tolerated 0–10 V	Single assessment whilst ongoing ESCS use	None
2	West et al., 2018 96	1	B; C5	Vancouver, BC, Canada	Cardiovascular function Stimulation resolved the orthostatic hypotension	Electrode: 5-6-5 Specify (Medtronic Inc. MN, USA) Stimulator: RestoreADVANCED (Medtronic Inc. MN, USA)	T11 – L1	Frequency: 35 Hz Pulse Width: 300 μs Intensity: 3.5 V	Assessment over 2-weeks whilst ongoing ESCS use	None
3	Darrow et al., 2019 97	2	A; T4-T8	Minneapolis, MN, USA	Cardiovascular and bowel/bladder function Restoration of cardiovascular function in one patient, achieved orgasm in one patient with and immediately after stimulation, improved bowel-bladder synergy in both patients while restoring volitional urination in one patient.	Electrode: Three columns5,6 16-contact paddle lead (Tripole and Proclaim Elite, Abbott, TX, USA) Stimulator: Primary cell internal pulse generator (Tripole and Proclaim Elite, Abbott, TX, USA)	L1 – S2	Frequency: 16–400 Hz Pulse width: 200–500 μs Intensity: 2–15 mA	Immediate effects of ESCS implantation	None
4	Nightingale et al., 2019 98	1	B; C5	Vancouver, BC, Canada	Cardiovascular function Increased absolute and relative peak oxygen consumption (15%–26%) during exercise with stimulation; peak oxygen pulse increased with stimulation.	Electrode: 5-6-5 Specify (Medtonic Inc. MN, USA) Stimulator: RestoreADVANCED (Medtronic Inc. MN, USA)	T11 – L1	Frequency: 35 & 40 Hz Pulse width: 330 & 420 μs Intensity: 3.5–6 V	6 testing sessions over 3 months whilst ongoing ESCS use	None
	TSCS- Autonomic and cardiovascular function
1	Phillips et al., 2018 99	5	3A, 2B; C5-T2	Los Angeles, CA, USA	Cardiovascular function During orthostatic challenge, electrical stimulation completely normalized BP, cardiac contractility, cerebral blood flow, and abrogated all symptoms	Not reported	Cathodal electrodes C7 – C8; Anodal electrodes iliac crests	Pulse mode: Continuous Frequency: 30 Hz Pulse width: 1 μs (monphasic) Intensity: 10–70 mA; normalized blood pressure for at least 1 min	Single session, at least 1-min of stimulation per bout	None
2	Knikou et al., 2019 100	10	2A, 2B, 1C, 5D; C6-T12	New York, NY, USA	Autonomic function Repeated stimulation increased homosynaptic depression in all SCI subjects. Stimulation decreased the severity of spasms and ankle clonus.	DS7A or DS7AH (Digitimer, UK)	Cathodal electrodes T10 to L1 – L2; Anodal electrodes paraumbilical level of umbilicus or iliac crests	Pulse mode: Continuous Frequency: 0.2 Hz Pulse width: 1 μs (monophasic) Intensity: Motor threshold	60-min stimulation, 5 sessions/week,3 weeks (16 sessions)	None
3	Sachdeva et al., 2021 101	1	A; C4	Vancouver, Canada	Autonomic dysreflexia When TSCS was delivered as a multisession therapy for 6 weeks post-SCI, the severity of autonomic dysreflexia was significantly reduced when tested in the absence of concurrent TSCS	Digitimer DS5, (Digitimer Ltd., UK).	Active electrodes T7 – T8; Reference electrodes iliac crests	Pulse mode: Continuous Frequency: 30 Hz Pulse width: 2 μs (biphasic) Intensity: 20–30 mA	Stimulation given after 30 s of onset of autonomic dysreflexia, 1 session	None
	TSCS- Spasticity
1	Hofstoetter et al., 2014 64	3	D; C5-T9	Vienna, Austria	Spasticity Increased index of spasticity from pendulum test, increased gait speed during stimulation in two subjects by 39%	Stimulette r2x+, (Dr. Schuhfried Medizintechnik GmbH, Austria)	Stimulating electrodes paraspinal T11 - T12; Reference electrodes paraumbilical level of umbilicus	Electrodes: Pulse mode: Continuous Frequency: 50Hz Pulse width: 2 μs (biphasic) Intensity: 20 ± 2 V (Supramotor)	30 min stimulation, single session (1 or 2 times)	None
2	Estes et al., 2017 102	18	1B, 6C, 11D; C2-T11	Atlanta, GA, USA	Spasticity Improvement in walking with TSCS. No significant change in spasticity.	Empi Continuum (DJO Global, CA, USA)	Single electrode over T11 – T12; single electrode over umbilicus	Frequency: 50 Hz Pulse mode: Continuous (biphasic) Intensity: Paresthesia in lower legs or feet (sensate) or highest level tolerated (insensate)	30-min stimulation, session every 2 days minimum, 2 weeks (5 sessions)	None

Abbreviations: AIS American Spinal Injury Association Impairment Scale; C, Cervical vertebrae; L, Lumbar vertebrae; T, Thoracic vertebrae; S, Sacral vertebrae.