Appropriate angle and depth in thoracic transforaminal epidural block in Koreans

Abstract

Background: Selective transforaminal epidural block has come to the for as a targetspecific modality in the treatment and diagnosis of spinal pain. Thoracic transforaminal epidural block (TTFEB) has the associated risk of pneumothorax. This article describes a retrospective study conducted using computed tomography (CT) imaging to investigate the TTFEB angle and depth appropriate to minimize the risk of pneumothorax in Koreans. Methods:The subjects of the present study were 100 randomly selected patients between 50 and 70 years of age found be free of thoracic disease according to chest CT performed in the present hospital. On the chest CT, the superior, middle, and inferior thoracic vertebrae were observed at the T2, T7, and T11 levels, respectively. Results:The average distance and the needle insertion angle from the skin point at which the needle may be inserted without piercing the lung to the intervertebral foramen were 117.8 ± 12.1 mm and 58.1 ± 6.1° at the T2 level, 85.6 ± 10.0 mm and 61.7 ± 4.3° at the T7 level, and 94.3 ± 8.7 mm and 64.4 ± 7.0° at the T11 level, respectively. Conclusions:The needle insertion at the point further than 40 mm, on the upper, middle thorax, if the needle pass from the inner vertebral body to lamina, it could be safer. However, on the lower thorax, needle could pierce the lung though the needle start from the inner vertebral body. Thus, it can be safer if the needle pass toward the exterior margin of lamina.