High-frequency (10 kHz) Spinal Cord Stimulation for the Treatment of Focal, Chronic Postsurgical Neuropathic Pain: Results from a Prospective Study in Belgium

Figures & data

Table 1. Key inclusion and exclusion criteria.

Inclusion criteria	Exclusion criteria
Diagnosed with chronic, focal, neuropathic pain following surgery of the trunk or the limb(s)^†	Significant chronic back or trunk pain resulting from failed back surgery
Average pain intensity of ≥5 out 10 cm on the VAS in the primary pain area	Pain in other area(s), not intended to be treated with SCS, that could confound evaluation of study end points
Stable neurological status measured by motor, sensory and reflex function	Diagnosis of progressive neurological disease

† No documentation of nerve injury is required. However, investigator must attribute treated pain syndrome as due to surgery/injury. Whenever possible, naming the nerve involved would be useful information.

SCS: Spinal cord stimulation; VAS: Visual analog scale.

Figure 1. Study flow.

(A) Octopolar leads were placed based on the location of pain. Lead placements for subjects with lower limb pain are shown on the left, for pain of the trunk in the center and for upper limb pain on the right. (B) Flow chart showing subject progression through the study.

EOT: End of trial; IPG: Implantable pulse generator.

Table 2. Subject demographic information and baseline pain characteristics.

Variable	n = 22
Gender, n (%)
Male	14 (64)
Female	8 (36)
Age, median ± SD, years (range)	52.5 ± 9.7 (27–77)
Duration of pain, median ± SD, years (range)	4 ± 5.1 (0–22)
Pain location, n (%)
Upper limb	3 (14)
Lower limb	16 (73)
Trunk	2 (9)
Right flank	1 (4)
Pain symmetry
Unilateral	20 (91)
Bilateral	1 (4)
Midline	1 (4)
Pain present prior to surgery
No	21 (95)
Yes	1 (4)
Number of surgeries
1	15 (68)
2 or more	7 (32)

SD: Standard deviation.

Figure 2. Pain intensity, assessed by VAS, over time.

(A) Mean VAS declined immediately upon initiation of trial stimulation and remained low through the end of the study at 12 months. (B) All but one of the subjects were responders, with ≥50% pain relief, after 12 months of stimulation. (C) Responder rates at 3-, 6- and 12-month assessments. (D) Remitter rates (VAS ≤2.5 cm) at 3, 6 and 12 months.

VAS: Visual analog scale.

Figure 3. Subjects and investigators had favorable perceptions of the effects of 10-kHz spinal cord stimulation.

(A) Patient satisfaction shown after 3 and 12 months of stimulation. (B) Responses to the Patient Global Impression of Change questionnaire after 3 and 12 months of stimulation. (C) Responses to the Clinician Global Impression of Change questionnaire after patients had received 3 and 12 months of stimulation.

Figure 4. Pain catastrophization and pain vigilance reduced in response to 10-kHz spinal cord stimulation.

(A) Pain declined both overall and in all four components of the MPQ-2. (B) Mean scores on the pain catastrophizing scale. (C) Mean responses for the Pain Vigilance and Awareness Questionnaire.

MPQ-2: McGill Pain Questionnaire.

Table 3. Results of assessments for disability, functional capacity, sleep quality and the likelihood of neuropathy.

Visit (n)	Baseline (n = 18)	Month 1 (n = 17)	Month 3 (n = 17)	Month 6 (n = 17)	Month 12 (n = 17)
GAF	59.5 ± 3.5	72.5 ± 2.6	77.5 ± 2.6	67.7 ± 4.7	75.7 ± 3.6
PDI^†	46.5 ± 2.5	30.2 ± 2.8	26.7 ± 3.2	25.8 ± 3.6	23.5 ± 3.9
SF-12	PCS: 27.5 ± 1.6		38.4 ± 2.2		40.4 ± 2.4
	MCS: 43.2 ± 2.8	ND	51.4 ± 2.7	ND	47.4 ± 2.7
PSQ-3^‡	Q1: 6.8 ± 0.7	1.4 ± 0.4	1.5 ± 0.4	1.7 ± 0.6	1.1 ± 0.4
	Q2: 6.0 ± 0.7	1.3 ± 0.5	1.6 ± 0.5	0.9 ± 0.4	1.6 ± 0.6
	Q3: 6.3 ± 0.8	1.4 ± 0.5	1.9 ± 0.5	1.1 ± 0.4	0.9 ± 0.4
DN-4	6.4 ± 0.6		2.1 ± 0.5		3.8 ± 0.6

† Scale of 0–70 with 70 being the worst score.

‡ Scale of 0–10 with 10 being the worst score and 0 being no disturbance; Q1: Trouble falling asleep because of pain; Q2: Awakened by pain during night; Q3: Awakened by pain in the morning.

DN-4: Douleur Neuropathique; GAF: Global Assessment of Functioning; MCS: Mental component score; ND: No data; PCS: Physical component score; PDI: Pain Disability Index; PSQ-3: Pain and Sleep Assessment; SF12: Short Form Health Survey.

Table 4. Study-related adverse events.

Cause	Status	Events (n)	n (%)^†
Total AEs		10	7 (38.9%)
Medical device site pain	Resolved, 4; ongoing, 1	5	4 (22.3%)
Medical device site infection	Resolved	1	1 (5.6%)
Medical device site swelling	Resolved	1	1 (5.6%)
Pain unrelated to device or original pain	Resolved	1	1 (5.6%)
Postoperative wound infection	Resolved	1	1 (5.6%)
Lead dislodgement	Resolved	1	1 (5.6%)

Total number of patients = 18.

† Number of patients with at least one AE in the specified category.

AE: Adverse event.

Data sharing statement

Clinical trial registration number: VT005076953. All the relevant data is included in the publication. Individual data cannot be shared due to privacy concerns.