Letters to the editor an L1 level sensory block was achieved 30 min after the injection.The second patient was a 77-year-old woman (152 cm, 43 kg) who, at her initial visit to our clinic, had complaints of lumbago and melalgia. Her medical history was unremarkable except for osteoporosis and severe diffuse spondylosis. A caudal epidural block was performed, with the patient in the left lateral decubitus position. Anatomical landmarks were easily identified, and 20 ml of 0.5% mepivacaine, mixed with 125 mg methylprednisolone was injected through the sacral hiatus with a 3.2-cm 22-gauge needle. As soon as the injection was completed, the patient complained of headache and nausea. Within 2 min, the patient became unconscious, and hypertensive (systolic blood pressure was 220 mmHg), and showed bradycardia (60 bpm). A few minutes later, her mental status improved, and she was taken to have brain computed tomography (CT). No convulsion was noted throughout this syncopal episode, and an adequate sensory block was achieved. The brain CT was negative.Both patients were discharged home without any sequelae after a 2-h stay in the recovery unit.A few cases of syncopal episodes after caudal epidural injections have been reported in the past [7,9]. In one report [9], a huge volume (60 ml) was injected into the epidural space, while in another [10], the patients had brain tumors and increased ICP. In old patients with spondylosis, the escape routes from the epidural space are considerably narrow, and the epidural compliance is considered to be low [2,5]. Although the injection volume in our practice was modest, there is no doubt that our technique triggered the transient syncopal attacks in the present two patients with severe spondylosis. Therefore, one could assume that the injection into the lowcompliant extradural space triggered an increase in ICP, a decrease in CBF, and the altered mental status. In future practice, the speed and volume of caudal epidural injections should be specifically tailored for older patients with severe spondylosis.
References1. Hirabayashi Y, Shimizu R, Matsuda I, Inoue S (1990) Effect of extradural compliance and resistance on spread of extradural analgesia. Br J Anaesth 65:508-513To the editor: Caudal epidural injection of local anesthetics is a commonly used technique to relieve lower back pain and sciatica. In certain conditions, however, the epidural injection may increase intracranial pressure (ICP) [1-5], and reduce both cerebral blood flow (CBF) and spinal cord blood flow (SCBF) [6]. These physiologic changes are occasionally manifested as altered mental status, with transient loss of consciousness. Due to the relatively wide space of the sacral canal [7,8], the increase in ICP is less with a caudal epidural injection than with a thoracic or lumbar epidural injection [5]. In patients with severe spondylosis and spinal canal stenosis, however, a caudal epidural injection can cause an acute increase in ICP and altered mental status. Here we report two patients with severe spondylosis in wh...