///2013 Abstract Details
2013 Abstract Details2019-08-02T16:57:45-05:00

A novel needle tip ultrasound for epidural guidance

Abstract Number: F 16
Abstract Type: Original Research

James Wall MD, MSE1 ; John Donovan MD2; Eric WIllis MSE3; Edward Riley MD4

Background: Ultrasound has become a cornerstone of procedural guidance including most peripheral nerve blocks. The epidural space remains a challenge for external linear array ultrasound guidance because the spine is highly echogenic due to irregular contours and offers only small median and paramedian windows for visualization. Obese patients are even more challenging for ultrasound guidance as the distance to the epidural space increases. A novel front viewing needle tip m-mode microultrasound was developed to improve epidural guidance. The needle tip design gains in signal-to-noise ratio as it approaches the epidural space.

Methods: Thoracic and Lumbar epidurals were performed in human cadavers by 2 attending OB anesthesiologists. The ultrasound within an introducer needle was placed in the midline of the spine to a depth of 2cm. The operator predicted whether they were aimed at bone or the epidural space and predicted the distance to the respective landmark. A Tuohy needle was then advanced through the introducer and loss of resistance (LOR) vs. striking bone was used to confirm or refute the prediction.

Results: 36 epidural attempts were made in 4 human cadavers. 78% of the passes predicted to be aimed at the epidural space were confirmed by LOR. The anesthesiologist was able to predict the depth of the epidural space to within an average of 4.7mm (1-14mm). 77% of the passes predicted to be aimed at bone were confirmed by striking the bone. The anesthesiologist was able to predict the depth of bone to within an average of 3.1mm (0-10mm).

Conclusion: A forward viewing needle tip ultrasound has advantages in real-time guidance to the correct path for epidural placement. Initial results indicate the potential to increase the percentage of first pass epidural successes resulting in improved procedural efficiency and decreased patient discomfort. A human trail is planned to investigate the performance of this device in clinical practice.

SOAP 2013