Epidural Space Localization: A Novel Slingshot Approach

Abstract

Background: The location of the epidural space for local anaesthetic injection can be a very challenging one. Methods of locating the epidural space depend on the negative pressure exhibited during the introduction of the epidural needle into the space.
Aim: This study describes the sling-shot technique to identify pressure changes in the syringe during puncture of the ligamentum flavum in identifying the epidural space. Knowledge of pressure changes might be of help to the anaesthetist who attempts to ascertain the location of the needle tip.
Method: Epidural punctures were performed in 30 patients, using an 18 guage Tuohy needle connected to a 10 ml epidural syringe with its grooved plunger mounted on a thin rubber sling. The plunger with the rubber sling was pulled and tip of the syringe mounted on the hub of the Tuohy needle. The epidural space was located by the loss of resistance to air technique.
Result: The mean age of the patients was 39.5±2.3 years while the mean height and weight were 163±4.1 cm and 78.9±3.8 kg respectively. With an advancing Tuohy needle the change in pressure was observed in all patients as evidenced by the collapsed grooved plunger on correct epidural space needle placement. The mean time from skin to space localisation was 17.3 seconds.
Conclusion: This novel method of epidural space identification is fast, safe and could increase the use of epidural technique in anaesthetic practice.

Keywords: epidural space localisation, sling-shot epidural syringe, accidental dural puncture, loss of resistance to air