Table 2.
Bivariable Analysis of Patient Factors and Pain Medication Use on SCS Outcome.
| 50% reduction in pain with trial Trial responders |
50% reduction in pain at one year Implant pain responders |
50% reduction in opioid use at one year† Implant opioid responders |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| Positive (n = 97) |
Negative (n = 18) |
p-value | Positive (n = 34) |
Negative (n = 57) |
p-value | Positive (n = 26) |
Negative (n = 65) |
p-value | |
| Age | 51.92 (12.74) | 43.00 (12.91) | 0.01 | 54.24 (13.50) | 51.35 13.24) | 0.32 | 49.82 (13.53) | 58.96 (10.46) | 0.01 |
| Male | 53 (54.64%) | 9 (47.37%) | 0.56 | 17 (50.00%) | 34 (59.65%) | 0.98 | 34 (52.31%) | 17 (65.38%) | 0.26 |
| Female | 44 (44.36%) | 9 (47.37%) | 0.87 | 17 (50.00%) | 23 (40.35%) | 0.98 | 31 (47.69%) | 9 (34.62%) | 0.26 |
| BMI (kg/m2) | 29.79 (6.15) | 27.33 (7.20) | 0.13 | 30.28 (5.23%) | 28.96 (6.48%) | 0.33 | 30.13 (6.42) | 27.9 (4.80) | 0.12 |
| Pain Descriptors | |||||||||
| Duration of Pain (years) | 7.41 (7.75) | 9.53 (7.57) | 0.30 | 5.98 (6.23) | 9.34 (8.99) | 0.06 | 8.62 (8.62) | 6.94 (7.19) | 0.38 |
| Burning | 42 (43.30%) | 7 (36.84%) | 0.60 | 13 (38.24%) | 25 (43.85% | 0.60 | 26 (40.00% | 12 (46.15%) | 0.59 |
| Sharp | 23 (23.71%) | 4 (21.05%) | 0.80 | 11 (32.35%) | 13 (22.81%) | 0.14 | 17 (26.15%) | 7 (26.92%) | 0.94 |
| Shooting | 22 (22.68%) | 4 (21.05%) | 0.88 | 11 (32.35%) | 8 (14.04%) | 0.31 | 17 (26.15%) | 2 (7.69%) | 0.05 |
| Electrical | 7 (7.22%) | 2 (10.53%) | 0.62 | 3 (8.82%) | 4 (7.02%) | 0.19 | 5 (7.69%) | 2 (7.69%) | 1.00 |
| Achy | 21 (21.65%) | 0 | 0.25 | 9 (26.47%) | 11 (19.30%) | 0.42 | 15 (23.08%) | 5 (19.23%) | 0.69 |
| NRS-11 Prior to SCS Trial | 7.72 (1.86) | 7.47 (2.06) | 0.60 | 8.25 (1.59) | 7.54 (1.85) | 0.07 | 8.40 (1.46) | 7.57 (1.86) | 0.04 |
| Number of Prior Surgeries At the Site of Pain | 2.74 (3.74) | 1.16 (1.26) | 0.07* | 3 (3.92) | 2.51 (3.48) | 0.54* | 2.82 (4.02) | 2.38 (2.48) | 0.61* |
| Pharmacologic Profile | |||||||||
| MEQ (mg) mean | 103.43 (203.38) | 62.03 (88.29) | 0.39* | 115.06 (257.51) | 98.59 (172.16) | 0.64* | 131.39 (237.88) | 38.13 (53.19) | 0.05* |
| MEQ (mg) median (IQR) | 48 (8, 135) | 7.5 (0, 90) | 105 (56, 225) | 60 (30, 180) | 67.5 (20, 247.5) | 60 (40,154) | |||
| Opioid Use % | 75 (77.31%) | 11 (61.11%) | 0.15 | 22 (64.71%) | 40 (70.17%) | 0.52 | 26 (100%) | 36 (55.38%) | 0.01 |
| SSRI | 20 (20.62%) | 3 (15.79%) | 0.63 | 8 (23.53%) | 10 (17.54%) | 0.22 | 12 (18.46%) | 6 (23.08%) | 0.62 |
| SNRI | 27 (27.84%) | 7 (36.84%) | 0.43 | 8 (23.53%) | 17 (29.82%) | 0.26 | 19 (29.23%) | 6 (23.08) | 0.55 |
| TCA | 22 (22.68%) | 5 (26.32%) | 0.73 | 9 (26.47%) | 10 (17.54%) | 0.10 | 16 (24.62%) | 3 (11.54%) | 0.17 |
| Gabapentin/Pregabalin | 52 (53.61%) | 15 (78.95%) | 0.04 | 14 (41.18%) | 33 (57.89%) | 0.12 | 33 (50.77%) | 14 (53.85%) | 0.79 |
| Baclofen | 5 (5.15%) | 0 | 0.31 | 2 (5.88%) | 2 (3.51%) | 0.59 | 3 (4.63%) | 1 (3.85%) | 0.87 |
| Benzodiazepine | 25 (25.77%) | 5 (26.32%) | 0.96 | 8 (23.53%) | 14 (24.56%) | 0.91 | 14 (23.08%) | 7 (26.92%) | 0.70 |
| Trial Characteristics | |||||||||
| Trial Duration (days) | 3.89 (1.47) | 3.44 (2.01) | 0.27 | ||||||
Measured as the difference between baseline NRS-11 pain score and NRS-11 pain score at one year divided by baseline NRS-11 Pain score e.g. (baseline—one year)/baseline.
All patients on Baclofen had 50% pain reduction with a trial of SCS and were able to reduce opioid consumption by 50% preventing an Odds Ratio from being generated. This was omitted form these analyses.
Indicates use of a nonparametric Mann-Whitey U test for comparison of groups.
Converted to equivalent mg of oral morphine. Measured as the difference between baseline opioid use and opioid use at 1 year divided by baseline opioid use e.g. (baseline—one year)/baseline.
CI, confidence interval; OR, odds ratio; SSRI, selective serotonin reuptake inhibitor; SNRI, serotonin-norepinephrine reuptake inhibitor; TCA, tricyclic antidepressant.