Neurological deficits following spinal anaesthesia are rare. We report two cases of persistent sacral nerve root deficits after continuous spinal anaesthesia (CSA) performed with hyperbaric lidocaine through a lumbar microcatheter. In both cases the dose of 5% lidocaine (5.7 and 4.3 ml) was greater than usual. In the immediate postoperative period the constellation of neurological deficits included perianal hypaesthesia, lower extremity paresis, urinary retention, and difficult defaecation. Both patients have residual perianal hypaesthesia and difficult defaecation. In these cases, the high-dose requirements of local anaesthetic via microcatheter CSA with focal sensory block suggests nonuniform distribution of the hyperbaric lidocaine. Microcatheter CSA may convey a unique risk of maldistribution of the local anaesthetic solution and local neurotoxicity.