We reviewed bladder contraction evolution after sacral anterior root stimulator implantation in thirty patients operated on from 1984 to 1991. Two patients underwent a complete denervation with a reinnervation within a maximal time of seventeen months. One patient underwent a lesion, like a neuropraxia with a complete recovery at four months. Five patients have undergone a partial denervation with a recovery of miction by neurostimulation within the time of eighteen months. In three patients, bladder contraction disappeared for various reasons.