Transient neurological symptoms after spinal anaesthesia with hyperbaric 5% lidocaine or general anaesthesia

Transient neurotoxicity of concentrated local anaesthetics has been thought to be the main reason for transient neurological symptoms after spinal ana esthesia. Profound musculoligamental relaxation by high doses of local anae sthetics may contribute to the development of postoperative musculoskeletal pain. In order to evaluate the role of the loss of strength of the support ive structures of the spine in the development of transient neurological sy mptoms, 60 patients (ASA I-II) undergoing minor orthopaedic, varicose vein or inguinal hernia operations were allocated randomly to receive spinal ana esthesia with hyperbaric lidocaine 50 mg ml(-1) (85-100 mg) or balanced gen eral anaesthesia with neuromuscular block. Patients were interviewed 24 h l ater and after 1 week they returned a written questionnaire. Transient neur ological symptoms, consisting of pain in the buttocks or pain radiating sym metrically to the lower extremities, occurred in eight patients (27%) recei ving spinal anaesthesia and in one patient (3%) receiving general anaesthes ia (P<0.05). We conclude that a transient neurotoxic effect of hyperbaric l idocaine 50 mg ml(-1) is probably the main reason for transient neurologica l symptoms after spinal anaesthesia but musculoligamental relaxation may co ntribute to the development of low back or leg pain after both anaesthetic techniques.