Central Neurostimulation for chronic pain
This review provides the updated guidelines for central neurostimulation techniques in chronic pain on the basis of a new systematic review and meta-analysis. As the aim of the study was to update previous European Federation of Neurological Societies (EFNS) guidelines on neurostimulation for neuropathic pain and search was expanded to new techniques and chronic pain conditions than neuropathic pain.
Evidence was assessed with the aid of Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system.
In contrast to prior guidelines or systematic reviews, the GRADE system was used to assess quality of evidence and propose recommendations. This search was extended to other chronic pain conditions, i.e. fibromyalgia, complex regional pain syndrome type I (CRPS I) and post-surgical chronic back and leg pain (CBLP) for which central neurostimulation has been largely assessed and Spinal cord stimulation (SCS), deep brain stimulation (DBS), epidural motor cortex stimulation (MCS), repetitive transcranial magnetic stimulation (rTMS) and transcranial direct electrical stimulation (tDCS) of the primary motor cortex (M1) or dorsolateral prefrontal cortex (DLPFC) were also assessed. These recommendations were strictly restricted to central neurostimulation because trials on peripheral stimulations are characterized by a great heterogeneity of methods.
In both fibromyalgia and CRPS I, involvement of the peripheral and central nervous system has been demonstrated, but it is still unclear whether these findings indicate a general pathophysiological role or only concern a subset of patients. In addition to this, patients suffering from these painful conditions are refractory to conventional medical management and may therefore be candidates for neurostimulation therapy. Most Spinal cord stimulation (SCS) trials conducted in post-surgical CBLP only considered patients with leg pain, although it is not clear whether this corresponded to radiculopathy or to referred pain from the lower back. Thus, post-surgical CBLP embraces a heterogeneous group of patients in which the presence and severity of nociceptive and neuropathic components may vary widely.
However, further large-scale multicentre studies are needed for non-invasive and invasive neurostimulation in neuropathic pain, CRPS and fibromyalgia and in addition to pain, these studies should collect patient reported outcomes of quality of life and treatment satisfaction.