The Effects of Shoulder Rotation on the Acoustic Window for Thoracic Paramedian Epidural Approach in the Lateral Decubitus Position

Abstract

Shoulder rotation significantly increased the dimension of the acoustic target window for paramedian thoracic epidural access in the lateral decubitus position at both T6/7 and T9/10 levels. Further clinical studies are needed to investigate the effect of shoulder rotation on thoracic epidural access.

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

“…Rotation of the ipsilateral shoulder in the lateral decubitus position causes a separation of the adjacent thoracic laminae and an outward movement of the spinous process from the midline, thus broadening the interlaminar space. This finding was consistent with those of previous studies that used ultrasound to evaluate the length of the PLL and reported the presence of an unobstructed path between the laminae by the bony structure (14)(15)(16). Shoulder rotation can alter the anatomical structure of the thoracic spine.…”

“…The thoracic epidural blockade is difficult because of the anatomical features of the thoracic spine, and few available methods can facilitate access. Several recent studies have demonstrated that ipsilateral shoulder rotation increases the length of the PLL, which is a dimension of the acoustic target window in ultrasound, suggesting that this position may promote thoracic epidural access (14)(15)(16). As noted previously, the effect of shoulder rotation remains to be confirmed in actual patients in a clinical setting.…”

“…The patient was then requested by the investigator to rotate the independent shoulder using the contralateral dependent shoulder as the axis of rotation. The shoulder was rotated to 30° by another assistant using a protractor tool (KHTSXR, Seoul, Republic of Korea) on a Samsung Galaxy S9 smartphone (Samsung Electronics Co., Seoul, Republic of Korea) (15).…”

“…Particularly, several studies have demonstrated that the shoulder rotation increases the acoustic window indicating the length of the PLL of the thoracic spine under ultrasound. However, those studies only compared the acoustic window of ultrasound, and the effect of shoulder rotation has not yet been confirmed in clinical practice (14)(15)(16). In this study, we aimed to determine whether shoulder rotation could improve thoracic epidural access in the lateral decubitus position.…”

A method for improving access to the paramedian epidural space in the lumbar region

“…1 Flexion plus shoulder rotation increases the dimension of the acoustic window for paramedian thoracic epidural access in the sitting position as well as the lateral decubitus position. 2,3 The effect of body position on the size of the paramedian acoustic window in the lumbar region, however, has not been reported to date. In a volunteer study, we measured the dimensions of the paramedian acoustic window in various body positions.…”