August Bier performed the first spinal anesthesia at the royal surgical hospital in 1898 (
3). At present, spinal anesthesia is one of the most common methods of modern regional anesthesia. Like other anesthesia techniques, spinal anesthesia is not free of complications (
4). The complication rates of spinal anesthesia have been reported from 1% to 17%, depending on the experience of anesthesiologists performing the procedure and the definition of a complication (
5). The complications of spinal anesthesia include hypotension, bradycardia, nausea and vomiting, urinary retention, insufficient block, hematoma or abscess around the injection site, post-dural puncture headache (PDPH), septic or aseptic meningitis, back pain, arachnoiditis, and neurologic sequelae. Although neurological complications caused by spinal anesthesia are rare, it is possible to occur. Possible neurological complications with spinal anesthesia include conus medullaris injury, transient neurologic syndromes, and permanent neurologic injury. The incidence of transient neurologic syndromes after spinal anesthesia varied between 0% - 7%. The reported incidence of permanent neurological injury following spinal anesthesia is 0 - 4.2 per 10000 patients. Local anesthetic neurotoxicity and needle trauma are the origins of most neurological complications. The pain during needle placement or injection of local anesthetic is reported in about two-thirds of patients with neurological complications. In the event of paresthesia, the needle should be immediately removed to avoid radiculopathy after surgery. It is also recommended that repeated injections of local anesthetics should be avoided to prevent toxic effects on the spinal cord (
6,
7). Hirabayashi et al. described a 33-year-old healthy woman who had neurologic sequelae following repeated spinal anesthesia. The first spinal anesthesia was performed with a 25-gauge Quincke needle in the right decubitus position. The hyperbaric dibucaine (7.5 mg) was injected into the subarachnoid space at the L3 - L4 interspace on the first attempt. Since the patient could flex entirely both feet and knees 15 min following the spinal anesthesia, they decided to repeat the spinal anesthesia. The repeated spinal anesthesia was performed again in the same fashion as the first spinal anesthesia with 6 mg of hyperbaric dibucaine. The surgery was done without problem after repeated spinal anesthesia. On the first postoperative day, she started to complain of loss of sensation in the buttocks and inability to void. The magnetic resonance imaging showed no abnormality in the spine. The numbness in the buttocks and urinary difficulties completely resolved within six weeks. They concluded that a subsequent injection at the same interspace following the initial failure of the spinal anesthesia is accompanied by the risk of neurologic complications (
8). Bhar et al. performed a study comparing 10 mg and 12 mg doses of intrathecal hyperbaric (0.05%) bupivacaine repeated after failed spinal anesthesia in 100 cesarean section patients. The spinal anesthesia was performed at the L3 - L4 or L4 - L5 interspace with 26-gauge Quincke needles in the sitting position with hyperbaric bupivacaine. The repeated spinal anesthesia was performed again in the same fashion as during the first spinal anesthesia. Unlike the previous report, Bhar et al. stated that spinal anesthesia could be safely repeated with hyperbaric bupivacaine in the cesarean section without neurological symptoms (
9). Additionally, Wipfli et al. reported repeated spinal anesthesia in a 78-year-old man with Guillain-Barré syndrome who underwent spinal anesthesia twice within six days for urologic procedures. Both spinal blocks were performed at the L4-L5 interspace with a 25-gauge Pencan
™ needle in the sitting position. Both spinal blocks were induced with hyperbaric bupivacaine (12.5 mg) and fentanyl (20 μg). After the spinal anesthesia had worn off, his neurological status was the same as before the surgery (
10). In this case, despite performing several spinal anesthesia procedures at short intervals, no complications and neurologic sequelae were observed. Therefore, it seems that spinal anesthesia with hyperbaric bupivacaine can be used repeatedly for a patient in some situation.