Spinal Cord Stimulation May Help for Low Back Pain
Spinal cord simulation (SCS) is proving itself a safe and effective method of treating some chronic back pain patients who have failed at least 6 months of conventional treatment, according to the results of a newly published study in the journal Pain Medicine.1
Of the 82 patients (Table 1) evaluated in the new study, 88% (72 patients) reported successful trials with high frequency (up to 10 kHz) spinal cord stimulation (HF10 SCS). The aim of the study was to expand the follow-up of HF10 SCS (Senza SCS System, Nevro Corp) efficacy over a longer period of time (2 years), noted the authors, which was led by Adnan Al-Kaisy, MD, The Pain Management and Neuromodulation Centre, Guy's and St. Thomas' Hospital in London, and Jean-Pierre Van Buyten, MD, AZ Niklaas Pain Centre, St Niklaas, Belgium. This research was needed as other studies have suggested that low-frequency SCS’s efficacy may lessen over time.2,3
Table 1. Inclusion and Exclusion Criteria for High-frequency Spinal Cord Stimulation
To participate in the study, patient must have met all of the following criteria:
- Be candidate for commercial SCS device (have failed to respond to at least 6 months of conventional treatment including pharmacological treatment, physical therapy, epidural injections and/or radiofrequency therapy)
- Have a primary diagnosis of chronic back pain (defined as lumbar-sacral pain) with or without leg pain with intensity of at least 5.0 out of 10.0 (average score over the last 30 days) on the VAS
- Be able to provide consent
- Be 18 years or older at the time of enrollment
- Be able to comply with study procedures, visits, and assessments.
Patient were excluded from study participation if they met any of the following criteria:
- Had obvious mechanical instability related to pain (diagnosed by imaging taken within the past 12 months)
- Have malignancies, have a life expectancy of less than 1 year
- Have a systematic infection, have any active implanted device whether turned off or on
- Are already participating in another clinical study
- Are pregnant/lactating or not using adequate birth control
- Have untreated major psychiatric comorbidity, serious drug related behavior issues
- Have bleeding complications or coagulopathy issues
- Are immunocompromised patients at risk for infection or other issues
- Are insulin-dependent diabetic who is not controlled through diet and/or medication
Modified from reference 1.
Although only 65 of the patients were followed for the full 2-year evaluation period, their results suggest that HF10 SCS is an effective non-pharmacological option for treating lower back pain. After 24 months, the patients in the study reported a mean pain score (VAS) of 3.3 ± 0.3, a decrease from the baseline mean score of 8.4 ± 0.1. The final VAS does suggest a slight increase from the 6-month evaluation that yielded a 2.7 ± 0.3 mean VAS score. The study investigators believe, however, that the VAS scores provide evidence that, “back pain relief was significant and sustained to 24 months.”
The study also yielded positive feedback from the patients. For instance, patients reported after 24 months that they experienced sustained improvements in sleep The patients in the study that suffered from leg pain in conjunction or exclusive from low back pain also reported reductions in pain after 24 months of treatment.
SCS also had an opioid-sparing effect, noted the investigators. At the beginning of the study, 86% of the patients were taking some form of opioid; after 24 months, this had reduced to only 57% of the patients. None of the patients suffered any neurological problems from the SCS treatment.
There have been other studies that provide evidence that SCS is an effective form of pain management.2,4 The current study by Al-Kaisy et al, actually yielded a higher success rate than other previous studies mentioned. This is significant as the latter studies only dealt with patients afflicted with leg pain, while the new study dealt primarily with back pain, which has been proven to be a more difficult type of pain to manage.5,6
There were some negative outcomes from the HF10 SCS treatment, however. While parasthesia was not an issue, other unfortunate problems did occur. Pocket pain was the most common device-related adverse event, occurring in 7 patients. Five patients also suffered from infections presumably from implantation. Four patients also experienced lead migration.
Al-Kaisy et al concluded that the treatment significantly improved the quality of life for the patients in the study. They noted that before implantation, 90% of their patients had pain that was so severe they were classified as crippled or severely disabled. After 24 months, though, this percentage dropped to 49%.
This study was sponsored by Nevro Corp.