Objective: We report the case of a 43-year-old patient with neuralgic shoulder amyotrophy who developed abducens palsy on the left 4 days after diagnostic lumbar puncture (LP), which recovered completely within 4 months. Results: Side effects after spinal tap are due to prolonged spinal fluid leakage and delayed closure of a dural defect causing intracranial hypotension, Downward 'sagging' of the brain and traction on cranial nerves may lead to abducens palsy. This case and a review of the literature illustrate the higher risk with the use of large-size traumatic needles in LP for cranial sixth nerve palsies. Conclusion: The presented case emphasizes the use of atraumatic small-size needles for lumbar puncture. (C) 2002 Elsevier Science B.V. All rights reserved.