Distribution range of cervical interlaminar epidural injections: a comparative study with 2.5 mL, 5 mL, and 10 mL of contrast.

BACKGROUND Cervical interlaminar epidural injection (CIEI) is widely used in the management of acute or chronic neck and upper extremity pain. There is no consensus regarding the optimal volume of solution to be used for CIEI. STUDY DESIGN Randomized, double blind controlled trial. OBJECTIVE The purpose of this study was to evaluate how many spinal segments would be covered with different volumes of contrast medium, given by fluoroscopically guided CIEI, in efforts to establish the optimal volume of medication with consideration of clinical pathologic lesions. METHODS One hundred and twenty-six CIEI were performed at C7-T1 in 133 patients. All patients were divided into 3 groups (A, B, and C) according to the amount of contrast medium used: 2.5 mL for group A, 5 mL for group B, and 10 mL for group C. The extent of contrast medium spread was determined by anteroposterior and lateral view under fluoroscopy. LIMITATION We did not evaluate the clinical outcomes with pain measurements during the study period. RESULTS The total number of vertebral segments of contrast media spread and spreading range of caudad or cephalad were significantly different among the 3 groups (P < 0.001). However, groups B and C in cephalad spreading and groups A and B in caudad spreading did not show any significant difference. A proportion of the patients with a cephalad spread of up to C4 and C2 in group A (59.5% and 31%) was significantly different from that in the other 2 groups (92.9% and 69.1% in group B and 97.6% and 73.8% in group C) (P < 0.001). CONCLUSION Five mL for CIEI at C7-T1 could be an optimal volume for distribution to the lower cervical spine for degenerative cervical spinal diseases, as well as to the upper cervical spine for head and facial pain.