Comparison of Thoracic Epidural Access with Lateral Decubitus and Shoulder Rotation Positions for Repeat Thoracic Epidural Blockade

Background: Shoulder rotation has been shown to increase the acoustic window of ultrasound for thoracic epidural access. However, this effect of shoulder rotation has not yet been confirmed in clinical practice. Objective: This study aimed to evaluate the effects of shoulder rotation on the thoracic epidural blockade in patients with acute or chronic pain in the thoracic region. Study Design: Prospective crossover trial. Setting: Pain clinic of our university in the Republic of Korea. Methods: Forty patients aged 20 - 80 years with acute or chronic pain in the thoracic region who were scheduled to undergo thoracic epidural blockade more than twice. Interventions: The patients underwent repeated fluoroscopy-guided thoracic epidural blockade via the paramedian approach in the lateral decubitus position either with or without shoulder rotation. The primary outcome measure was the attempt time to the confirmed spread of contrast. The number of attempts, total procedure time, vertical interpedicular distance, contrast spreading length, and complications were compared between the 2 positions. Results: The median attempt times in the lateral decubitus and shoulder rotation positions were 138.8 and 132.5 seconds, respectively, and this difference was significant (P = 0.004). Compared with the lateral decubitus position, the shoulder rotation position was also associated with a significantly lower number of attempts (P = 0.03), shorter total procedure time (P < 0.001), and greater vertical interpedicular and contrast spreading distances (P < 0.001 and P = 0.02, respectively). Limitations: The operator in this study was not blinded to the patient groups. Other researchers observed the operator's procedure and evaluated and recorded the data in an attempt to overcome this bias. However, it was difficult to completely avoid the bias. Second, epidural blockade was performed at various levels (T3-11), and the anatomical features vary among thoracic spine levels. Conclusions: The study findings demonstrate the clinical benefits of the shoulder rotation position versus the lateral decubitus position in terms of successful epidural access during thoracic epidural blockade using the paramedian approach.