Subdural motor cortex stimulation: feasibility, efficacy and security on a series of 18 consecutive cases with a follow-up of at least 3 years.

Abstract

Motor cortex stimulation (MCS) is considered to be an effective treatment in some types of chronic refractory neuropathic pain. The aim of this study is to evaluate and confirm the feasibility, efficacy and security of our surgical technique for subdural motor cortex stimulation (SD MCS) on 18 consecutive cases with follow-up of at least 3 years. Our population consists of 18 consecutive patients (12 male) between 2000 and 2010, with a mean age of 63 years (11-91). The mean follow-up was 86 months (20-140 months). We identified the central sulcus by using classical anatomic landmarks and neuronavigation (BrainLab system; BrainLAB, Inc., Redwood City, CA). An elongated craniotomy (3 cm in length, 1 cm in width) was performed followed by linear opening of the dura mater. An eight-polar plate electrode (Specify Lead, 3998; Medtronic, Minneapolis, MN) was then slipped smoothly through this linear opening. In patients with interhemispheric electrodes (patients 2 and 17), we performed a parasagittal craniotomy of 4 cm length and 2 cm width. At last follow-up assessment, 14 patients had a favourable outcome (77.7 %): 10 patients with excellent relief of pain (>80 %), 1 with good relief of pain (60-80 %) and 3 with satisfactory relief of pain (50-60 %). Four patients showed bad results (<50 %). We did not observe any late complications specific to SD MCS. We report an efficacy at least as good as ED MCS, with no complications specific to SD MCS, even with prolonged follow-up. The data are insufficient to actually prove a lower energy use in SD MCS.