TABLE 2.
Patient Demographics of 35 Complex Regional Pain Syndrome Patients Treated Between January 1998 and December 2016 and Multivariate Analysis of the Variables Associated With Successful Trial Stimulation and Spinal Cord Stimulation Explantation
| Permanent SCS implanted n = 27 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Trial only n = 8 | SCS explanted n = 8 | SCS in use at the end of follow-up n = 19 | ||||||||
| All | % | OR (95% CI)a | P | All | % | HR (95% CI)b | P | All | % | |
| Gender | ||||||||||
| Female | 5 | 63 | 1 | 5 | 63 | 1 | 14 | 74 | ||
| Male | 3 | 37 | 1.8 (0.16-20) | .63 | 3 | 37 | n.d. | .32 | 5 | 26 |
| Age (mean ± SD) | 54 ± 11 | 0.95 (0.87-1.0) | .29 | 41 ± 13 | 0.38 (0.04-3.5) | .39 | 51 ± 13 | |||
| Location of pain | ||||||||||
| Arm(s) | 4 | 50 | 1 | 4 | 50 | 1 | 10 | 53 | ||
| Leg(s) | 3 | 38 | n.d. | 1.0 | 4 | 50 | n.d. | .63 | 9 | 47 |
| Pelvis | 1 | 12 | 0 | 0 | 0 | 0 | ||||
| Duration of pain in years before SCS (mean ± SD) | 3 ± 3 | 1.2 (0.77-1.7) | .50 | 4 ± 3 | n.d. | .33 | 5 ± 3 | |||
| Estimated incident leading to CRPS | ||||||||||
| Conservatively treated bone fracture or other trauma | 4 | 50 | 1 | 3 | 43 | 1 | 10 | 53 | ||
| Orthopedic surgery or other operative trauma | 4 | 50 | 2.1 (0.26-17) | .49 | 4 | 57 | n.d. | .49 | 9 | 47 |
| Missing | 1 | |||||||||
| Sympathetic blockade | ||||||||||
| Yes | 7 | 88 | 1 | 3 | 60 | 1 | 14 | 74 | ||
| No | 1 | 12 | 3.5 (0.22-54) | .38 | 2 | 40 | n.d. | .64 | 5 | 26 |
| Missing | 3 | |||||||||
| Response to sympathetic blockade | ||||||||||
| Good or better than before | 5 | 83 | 2 | 67 | 10 | 71 | ||||
| Poor or worse than before | 1 | 17 | 1 | 33 | 4 | 29 | ||||
| Not used or missing | 2 | 5 | 5 | |||||||
| Spinal segment of electrode | ||||||||||
| Cervical | 4 | 50 | 1 | 5 | 63 | 1 | 10 | 53 | ||
| Thoracal | 4 | 50 | n.d. | 1.0 | 3 | 37 | n.d. | .61 | 9 | 47 |
| Type of electrode | ||||||||||
| Surgical | 7 | 87 | 1 | 7 | 87 | 1 | 10 | 53 | ||
| Percutaneous | 1 | 13 | 6.0 (0.46-77) | .17 | 1 | 13 | n.d. | .84 | 9 | 47 |
SCS = spinal cord stimulation. n.d. = not defined. CRPS = complex regional pain syndrome.
aOdds ratio is calculated using multivariate logistic regression analysis for a successful trial.
bHazard ratio is calculated by using Cox regression analysis for SCS explantation.