The optimal oblique angle of fluoroscope for thoracic sympathetic ganglion block

Objective: The target in the thoracic sympathetic ganglion block (TSGB) is the anterior edge of the costovertebral articulation along the lateral surface of vertebral bodies T2-4. The present study attempts to determine an optimal safe angle for fluoroscopy in fluoroscope-assisted TSGB through the use of chest CT scan images. Additionally, we seek to determine if differences in these measurements exist in patients with chronic obstructive pulmonary disease (COPD). Methods Chest CT scans from 320 patients were included. The range of angle and entry point distance to midline was measured in all subjects. The range of angle was from the minimum angle to thoracic sympathetic ganglion passing over the lateral aspect of body to the maximum angle to the thoracic sympathetic ganglion not puncturing the pleural space. Additionally, these measurements from 50 COPD patients were subsequently compared age-matched individuals without COPD. Results No significant difference in optimal angle was found for any of the levels between T2 and T4. The optimal angle was significantly different between right and left sides, although no such difference was identified between genders. The older patients had a significantly smaller optimal angle than the younger. Similarly, individuals with COPD had a significantly smaller optimal angle and entry distance. Interpretation The measurements derived from this study can be used as a reference for TSGB and radiofrequency lesioning to prevent the complications. Specifically, our data indicate that the optimal oblique angle of fluoroscopy is 18°-19° for non-COPD patients and 16°-17° for COPD patients.