Epidural Saline and Combined Epidural-Spinal Anesthesia

Abstract

In Response: We appreciate Tanaka and Nishikawa's interest in our article [1]. They raised the following three points, which we will address separately. 1. Seven milliliters of contrast medium was injected into the subarachnoid space because the upper level of the contrast medium had already reached L3 or L2. The volunteers were placed in the recumbent 45[degree sign] head-up position to prevent spontaneous cephalad spread of the contrast medium into the subarachnoid space. This was not identical with clinical conditions, but immediately after a lumbar epidural injection of saline, the upper level of the contrast medium, which had greater specific gravity, began to increase despite the 45[degree sign] angle. 2. The duration of the analgesia for surgery after epidural injection of saline is similar to the action time of a local anesthetic. Therefore, the increased analgesic level after epidural injection of saline may not be related to the additive effect of hypalgesia produced by epidurally administered saline. 3. The preliminary study confirmed that raising a fluoroscopic Table towardthe head side at 45[degree sign] can prevent the cephalad spread of the contrast medium in the subarachnoid space. The duration from intrathecally injected contrast medium to epidurally injected saline was 5 min, so we believe that the time was not an important factor in our clinical model using myelography. Tetsuo Takiguchi, MD, PhD Takatoshi Okano, MD Hirotoshi Egawa, MD Yoshinori Okubo, MD, PhD Kyoko Saito, MD Toshimitsu Kitajima, MD, PhD First Department of Anesthesiology; Dokkyo University School of Medicine; Tochigi 321-0293, Japan