3. Clinical evidence. With regard to acute relief of chronic SCI pain by DBS in PAG/PVG, the Investigators believe that useful evidence is non-existent at present, but that the benefits of PAG/PVG stimulation for other kinds of pain strongly justify a targeted evaluation. In the above-cited 2005 meta-analysis, pain originating from spinal cord injury was identified in 10 cases and leads were internalized in 7 of these cases, of which 5 showed good long-term pain relief. Unfortunately, it is impossible to tell from the cases described in the original articles, many from the 1970s, whether the sensory thalamus (a different brain region, probably less appropriate) or the PAG/PVG or both were stimulated. Moreover, the clinical literature on DBS for SCI pain rarely describes the type of injury (segmental level, completeness, age or onset, etc.) and often includes non-typical SCI in its summary categories (e.g., root avulsion, myelopathy). Because of the conflation of stimulation sites and the poor characterizations of the injuries, these factors need to be revisited in a more thorough analysis.