Spinal Cord Stimulation and Pain Relief in Painful Diabetic Peripheral Neuropathy

A Prospective Two-Center Randomized Controlled Trial

Rachel Slangen; Nicolaas C. Schaper; Catharina G. Faber; Elbert A. Joosten; Carmen D. Dirksen; Robert T. van Dongen; Alfons G. Kessels; Maarten van Kleef

Disclosures

Diabetes Care. 2014;37(11):3016-3024. 

In This Article

Results

Patients

Between 1 February 2010 and 28 February 2013, we screened 110 patients with PDPN at the MUMC+ and at the Radboud UMC. Study enrollment, randomization, and follow-up are shown in Fig. 1. Patient baseline demographics and clinical characteristics are presented in Table 1.

Figure 1.

Randomization and follow-up.

In one patient, the implantation of the stimulation lead was complicated by a dural puncture, and the procedure of this patient was immediately stopped (see below). Therefore, 21 of the 22 patients who were assigned to the SCS group underwent a 2-week trial stimulation period. One patient was not willing to fill out questionnaires after negative trial stimulation. After 6 weeks, another patient withdrew from the study due to infection and removal of the SCS system.

Results of Trial Stimulation

Trial stimulation was successful in 17 of the 22 SCS group patients (77%). All 17 patients reported pain relief during daytime of at least 50% as compared with baseline, and 12 patients (55%) showed reduced pain of ≥50% during nighttime. All 17 patients had a minimal score of 6 (much improved) for the PGIC for pain and 14 patients (64%) for the PGIC for sleep.

Outcome Measurements

ITT analysis was performed for 22 patients assigned to the SCS group and 14 patients assigned to the BMT group. Outcome data were available for 19 patients (86.4%) in the SCS group and 14 patients in the BMT group (100%) at 6 months.

Treatment success of SCS was observed in 13 out of 22 patients (59%) and in 1 out of 14 BMT patients (7%) (P < 0.009) (Table 2). The mean pain score on the NRS during daytime in the SCS group was reduced by 3.1 points at 6 months as compared with no change in pain score in the BMT group (P < 0.001) (Fig. 2). In total, nine patients (41%) reported ≥50% pain relief during daytime in the SCS group, as compared with 0% in the BMT group (P < 0.001). Mean pain at night was reduced by 2.4 points in the SCS group compared with 0.9 points on the NRS in the BMT group (P < 0.003) (Fig. 2). Eight patients (36%) showed ≥50% pain relief during nighttime in the SCS group, as compared with one patient (7%) in the BMT group (P < 0.01). Of the 22 SCS patients, 12 (55%) scored ≥6 (much improved) on the PGIC for pain (P < 0.001) and 8 (36%) scored ≥6 on the PGIC scale for sleep (P < 0.011). None of the BMT patients showed any difference on the PGIC scale for pain or sleep. After adjusting for possible unbalanced distributions of the baseline characteristics, the OR for treatment success was 18.8 (95% CI 2.1–170.2). Sex was the only covariate that had a significant influence on the outcome, and adjusting for sex increased the OR to 24.7 (2.4–250.2). The results at 3 months were similar to the results obtained at 6 months and are presented in Supplementary Table 1 http://care.diabetesjournals.org/content/37/11/3016/suppl/DC1.

Figure 2.

Mean pain scores at daytime and nighttime. ITT analysis

Results of pain severity, pain interference with daily life, qualities of pain, HRQoL, pain interference with sleep quality and quantity, and mood in both groups are presented in Table 2 and Supplementary Table 1 http://care.diabetesjournals.org/content/37/11/3016/suppl/DC1. Both the PSI and PII showed significant differences between the SCS and the BMT group (P < 0.001 and P < 0.008, respectively). The characteristics of neuropathic pain were improved in the SCS group compared with the BMT group, with the exception of deep pain. After 6 months, the mean utility score of the EQ-5D was increased in the SCS group with 0.25, and in the BMT group, the change was 0.00; this difference was not statistically significant (P < 0.776). No significant differences between the SCS and BMT groups were seen on the visual analog scale (VAS) of the EQ-5D (Fig. 3) and the MCS and PCS of the MOS SF-36. Mood, as assessed with the BDI, did not differ between the two groups. Sleep quantity, optimal sleep, and sleep quality were of relative poor quality in both groups, but no significant effect of SCS was observed (Table 2).

Figure 3.

EQ-5D utility score and EQ-5D current health

Seven out of 22 patients (32%) of the SCS group were able to reduce their pain medication, and for 2 of them, the SCS became the sole treatment for their PDPN pain. Twelve patients (55%) did not change their medication in combination with SCS treatment. Four patients (29%) in the BMT group reported an increased use of medication compared with baseline, and one patient changed to another category of neuropathic pain medication. In 9 out of 14 (64%) patients, medication use was unchanged as compared with baseline.

Complications and (Serious) Adverse Events

Serious adverse events were noted in two patients. Implantation of the lead for test stimulation was complicated by a dural puncture, causing a postdural puncture headache in one patient (male, 65 years of age). After conservative treatment was started, the patient was discharged from the hospital. Three days after the procedure, the headache suddenly increased and within minutes, the patient became unresponsive. The patient was transferred to the nearest hospital where a CT scan showed a large subdural hematoma over the left hemisphere with a diameter of 26 mm, causing a midline shift of 19.8 mm. Despite immediate surgical evacuation of the subdural hematoma, the patient did not regain consciousness and died 10 days after surgery.

Another patient contracted an infection of the SCS system 6 weeks after the SCS system implantation, which was subsequently removed. Despite treatment with antibiotics, the patient recovered slowly but not completely. The patient also developed an autonomic neuropathy. After a consultation with the patient, it was decided that the SCS system would not be reimplanted.

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