• Mi Geum Lee, Seung Hyun Chung, Ae Ryoung Lee, Su Ran Yu, Wol Seon Jung, Dong Chul Lee, Hee Yeon Park, and Yun Suk Choi.
• Department of Anesthesiology and Pain Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea.
• Pain Physician. 2024 May 1; 27 (4): 229234229-234.

BackgroundTransforaminal epidural steroid injection (TFESI) is commonly used for radicular pain, but can lead to an unintentional injection into the retrodural Space of Okada (RSO), an extradural space located dorsal to the ligamentum flavum, instead of the epidural space.ObjectivesTo determine the prevalence and describe the fluoroscopic imaging features of an unintentional injection into the RSO during a TFESI and to review the history of injections into the RSO.Study DesignObservational study and original research.SettingThis work was conducted at Jeju National University School of Medicine, Jeju, Republic of Korea.MethodsA total of 5,429 lumbar TFESIs performed from the September 1, 2018 through October 31, 2021 were analyzed for unintentional RSO injections using fluoroscopic-guided contrast medium patterns.ResultsThe rate of unintentional injection into the RSO was 0.20% (11 incidents). Contrast medium patterns in the RSO had a sigmoid or ovoid shape confined to the affected facet joint, or a butterfly-shaped pattern extending into the contralateral facet joint, but rarely extending beyond the upper or lower level.LimitationThe rarity of unintentional injection into the RSO prevented a randomized controlled study design.ConclusionsCareful fluoroscopic examination of contrast medium patterns during lumbar TFESI is crucial to identify needle placement in the RSO. If detected, the procedure can be corrected by slightly advancing the needle into the foramen.

22 keywords...

hide…