Abstract
Introduction
Despite globally favorable outcomes of SCS, a significant proportion of FBSS patients do not obtain adequate coverage of low back pain. PNS has obtained the CE mark in Europe for the treatment of chronic refractory neuropathic pain and is now commonly used in some countries to target back pain. However, the potential value of combining SCS and PNS as ”hybrid stimulation” remains poorly described with only isolated case reports or limited experience in various indications. The “CUMPNS” comparative randomized study is designed to demonstrate the potential analgesic efficacy of PNS in addition to previously implanted SCS, to treat the residual low back pain component pain in refractory FBSS patients.
Material and Methods
All patients are randomized 1:1 in to 2 groups (SCS+PNS vs SCS). Group 1 (SCS+PNS) receives “hybrid stimulation” with PNS implantation one month after the inclusion visit. In the second group, patients continue to be treated with SCS alone for 4 months post-inclusion before having access to PNS. The main objective of this study is to demonstrate the added value of subcutaneous PNS by comparing the ability of hybrid stimulation (SCS+PNS) versus SCS alone to improve analgesic efficacy, functional outcome on quality of life and coverage of the residual low back pain component at three months. This variation in the pain surface area covered is evaluated by mapping, using the Neuro-Mapping Tools software (N3MT).
Results
Patient recruitment in the CUMPNS trial began in February 2013. The inclusion period will end in February 2015 and primary endpoint findings will be available at the end of 2016. To date, five patients have been included and four have been implanted. Neuromodulation is one of the most rapidly growing fields of medicine, involving many diverse specialties and impacting on hundreds of thousands of patients with numerous disorders worldwide. In addition to the development of SCS, PNS appears to be an interesting option that can be considered in several specific indications, especially refractory focal pain and axial pain. PNS npresents several advantages, including easy repositioning in the case of lead migration and constitutes a minimally invasive technique. Stimulation is applied directly over the area of pain, and the use of multichannel lead arrays allows flexible programming. Coverage can be easily adjusted over time according to variations in pain. PNS also has other advantages, as it is safe, with no risk of neurological sequelae such as cerebrospinal fluid leak or meningitis due to dural puncture, paralysis due to spinal cord injury, etc.
Conclusion
The present study should provide an opportunity, for the first time, to prospectively evaluate and objectively compare the ability of a combined hybrid neurostimulation technique to increase the coverage of painful areas and to try to correlate this coverage with clinical outcomes.