Effects of Multiple Waveforms on Patient Preferences and Clinical Outcomes in Patients Treated With Spinal Cord Stimulation for Leg and/or Back Pain.

Objectives: We present the results of a prospective, randomized, crossover, single-blind, study in which each patient is in control of himself. The aim was to evaluate subperception-based (SP-SCS) waveforms in previously implanted spinal cord stimulation (SCS) patients with leg and/or back pain due to failed back surgery syndrome, who experienced only paresthesia-based stimulation (PB-SCS). Patients with PB-SCS experience in SCS was 4.7 years (SD 2.9).

Materials And Methods: We enrolled 28 consecutive patients. Treatment consisted of seven days of PB-SCS, followed by a randomized, crossover phase to test SP-SCS waveforms (burst or 1 kHz frequency, seven days each). A maximum of three-day washout period separated each stimulation program.

Results: Statistically significant pain relief was maintained using both SP-SCS waveforms, as indicated by the differences between the pre-PB-SCS numeric pain rating score (mean 9) and the pain score after using the burst program (pain relief 52%) or the 1 kHz program (pain relief 51%). There was no statistically significant superiority among PB-SCS, burst, and 1 kHz stimulation. Overall, 50% of patients preferred PB-SCS, 42% chose to move to SP-SCS stimulation, one patient was unable to give feedback, and one patient was unsuccessful with any type of stimulation. Overall, SCS has shown to be successful in pain relief and the patients switched to a SP-SCS waveform only for having higher pain relief.

Conclusions: There was a high heterogeneity regarding waveform preference, with patients who preferred to feel the tingling sensation and those who chose a SP-SCS option, mainly for greater pain relief. In general, SCS is successful, resulting in high pain relief, improvements in quality of life, and little depression. Overall, 42% patients benefited from the novel SP-SCS stimulation waveforms.