Abstracts of Posters; Presented at the International Anesthesia Research Society; 73rd Clinical and Scientific Congress; Los Angeles, CA; March 12-16, 1999: Obstetric Anesthesia
INTRODUCTION: Smaller gauge atraumatic needles, such as the conical-point Whitacre and Gertie Marx needles, and the pencil-point Sprotte needle are commonly used for spinal anesthesia. However, a spinal needle with the most desirable insertion characteristics and a low occurrence of complications is yet to be identified. This randomized study was designed to compare the insertion characteristics and the incidence of complications with 24G/25G Whitacre, 24G/25G Sprotte[registered sign], and 24G/26G Gertie Marx[trade mark sign] and 26G Atraucan spinal needles.
METHODS: Following IRB approval, informed consent was obtained from 1379 ASA 1-2 patients undergoing postpartum tubal ligation. They were randomly assigned to receive spinal anesthesia with either a 24G Whitacre (W24), 25G Whitacre (W25), (Becton-Dickinson); 24G Sprotte[registered sign] (S24), 25G Sprotte[registered sign] (S25), (B. Braun Inc.); 24G Gertie Marx[trade mark sign], (GM24), or 26G Gertie Marx[trade mark sign] (26G) (IMD, Inc.) spinal needle. A standard midline approach was used with patients in the sitting position. After CSF aspiration, 1.3 - 1.5 ml of Lidocaine 5%, was injected. The following data were collected: positive dural click, time for three CSF drops after the appearance of CSF at the end of the hub of the needle, and successful block. Any missed segments or peritoneal discomfort during surgery was treated by infiltrating with 5-10 mL of 1% Lidocaine, and in the event of a failed block, general anesthesia was induced. The patients were followed in the postoperative period by an observer blinded to the study groups for headache, backache, and any other complications. ANOVA with Bonferroni multiple comparison test and Chi-square test were used for statistical analysis as appropriate. A p value < 0.05 was considered significant.
RESULTS: Patients in all three groups were similar with respect to demographic data. Positive dural click was greater in the GM24 and GM26 groups than in the other groups. The rate of CSF flow was greater through the W24 and GM24 needles than through the other needles. There were no differences observed between groups in terms of need for infiltration, failed block, and PDPH (posdural puncture headache) (Table 1)
DISCUSSION: In this study a high rate of successful spinal anesthesia was achieved with all six needles. The higher CSF flow rate with the GM24 and W24 needles may be attributed to the design of the tip and the size of the needles. A higher incidence of a distinct dural click with the Gertie Marx[trade mark sign] needle seems to be related to its rounded edge conical-point tip. Technically, rapid CSF flow and a positive dural click are desirable features of a spinal needle. However, a large scale study is required to compare the incidence of PDPH with these atraumatic spinal needles.