1. 2021;24;E51-E59Evaluation of Contralateral Oblique and Lateral Views for Mid-Thoracic Epidural Access: A Prospective Observational Study
   Observational Study
   Seong-Soo Choi, MD, PhD, Han Park, MD, Ji-Hoon Sim, MD, Jonghyuk Lee, MD, Syn-Hae Yoon, MD, and Doo-Hwan Kim, MD.

BACKGROUND: The mid-thoracic region has been known to be the most difficult area when accessing epidural space despite using fluoroscopy. Contralateral oblique (CLO) view has been considered for use; however, it has not been evaluated in the mid-thoracic region.

OBJECTIVE: To evaluate the CLO view for mid-thoracic epidural access (TEA).

STUDY DESIGN: A prospective observational study.

SETTING: The study took place at a single pain clinic within a tertiary medical center in Seoul, Republic of Korea.

METHODS: A total of 30 patients participated in this study. After securing the mid-thoracic (T4–8) epidural space, fluoroscopic images were obtained. The needle tip location relative to the ventral interlaminar line (VILL), and the needle tip and laminar visualization were measured and analyzed on the CLO views at 40, 50, 60 degrees, and measured angle, and the lateral view.

RESULTS: The needle tip was clearly visualized in all CLO views, compared with the lateral view (100% vs. 36.7%, P < 0.001). The visualization of the laminar margin and the needle tip location on (or just anterior to) VILL using the CLO measured angle were significantly clearer compared with those in the CLO view at 40 and 50 degrees and the lateral view (laminar margin: 40°, 56.7% vs. 3.3%, P < 0.001; 50°, 56.7% vs. 26.7%, P = 0.012; 90°, 56.7% vs. 26.7%, P = 0.035; needle tip location: 40°, 96.7% vs. 26.7%, P < 0.001; 50°, 96.7% vs. 63.3%, P = 0.002; 90°, 96.7% vs. 66.7%, P = 0.012). There was no difference in these values between the CLO view at 60 degrees and CLO measured angle.

LIMITATIONS: Subjective and ambiguous criteria of evaluation may induce bias despite final measured values based on the consensus of an independent investigator.

CONCLUSION: A CLO view at 60 degrees and CLO measured angle view can provide clearer visualization and more consistent needle tip location than the lateral and other CLO angle views for mid-TEA. A CLO view at 60 degrees and CLO measured angle views could be used to identify the needle location and achieve success in mid-TEA.

KEY WORD: Chronic pain, contralateral oblique view, fluoroscopy, lateral view, mid-thoracic, pain management, epidural analgesia, ventral interlaminar line

Trial registration number: NCT03789955