Neuropathic limb pain and spinal cord stimulation: results of the dutch prospective study

Baseline and 12-month follow-up data from a prospective controlled study on patients treated with SCS for neuropathic limb pain (NLP) are analyzed critically. The outcome on pain, use of medication, and quality of life are reported and compared with the literature. Patients enrolled from April 1999 to December 2001 were part of a quality system study by the Dutch Working Group on Neuromodulation. In two years, more than 400 patients were admitted for several indications of chronic neuropathic pain. Failed back surgery syndrome (FBSS) and complex regional pain syndrome (CRPS) were the largest cohorts. FBSS was defined as persistent limb pain with/or without concomitant minor back pain after prior surgery for a slipped lumbar disc or spinal instability. SCS was a last resort therapy. Two criteria were used for eligibility: a SCL-90 score below 225 and a mean visual analog score (VAS) of four days according to Jensen of ≥ 5. One hundred sixty nine patients were registered for FBSS. Thirty four did not fulfill the eligibility criteria, and 135 received several questionnaires for baseline evaluation. Thirty patients did not have successful trial stimulation (< 50% pain relief), leaving 105 patients for implantation. The mean scores of the baseline evaluation were: SCL 137 (SD 28.3) and VAS 7.3 (SD 1.2), McGill pain questionnaire (MPQ) total PRI: 22.4 (9.4), Sickness Impact Profile (SIP) total score: 19.4 (SD10.1), ROLAND disability (RD) 16.9 (SD 3.5) and EUROQOL (EQ-5D) 55.2 (SD 14.5) (simple linear index). Medication quantification scale at intake was 11.5 (SD 7.9). 56.2% of the patients used one or more narcotic drugs at intake. 82% of the patients did not have a paid job at the time of inclusion. 61% of the patients lost their job due to their medical problems. Scores at 12-m follow-up were VAS 3.0 (SD 2.4), MPQ 10.8 (SD 8), SIP 11.7 (SD 9.4), EQ-5D 38.2 (SD 19.2) and RD 12.4 (SD 4.8). The difference between baseline and 12-m follow-up is statistically significant for all measures. We conclude that the outcome measures indicate that SCS significantly reduces pain and enhances quality of life in patients having NLP not responding to other adjuvant therapy. Recommendations are proposed to make studies more comparable.