A transient neurological deficit following intrathecal injection of 1% hyperbaric bupivacaine for unilateral spinal anaesthesia

We describe a case of transient neurological deficit that occurred after unilateral spinal anaesthesia with 8 mg of 1% hyperbaric bupivacaine slowly injected through a 25-gauge pencil-point spinal needle. The surgery and anaesthesia were uneventful, but 3 days after surgery, the patient reported an area of hypoaesthesia over L3-L4 dermatomes of the leg which had been operated on (loss of pinprick sensation) without reduction in muscular strength. Sensation in this area returned to normal over the following 2 weeks. Prospective multicentre studies with a large population and a long follow-up should be performed in order to evaluate the incidence of this unusual side effect. However, we suggest that a low solution concentration should be preferred for unilateral spinal anaesthesia with a hyperbaric anaesthetic solution (if pencil-point needle and slow injection rate are employed), in order to minimize the risk of a localized high peak anaesthetic concentration, which might lead to a transient neurological deficit.