Cervical transforaminal epidural block using low-dose local anesthetic: A prospective, randomized, double-blind study

Objectives: Intra-arterial injections of local anesthetic during cervical transforaminal epidural block (TFEB) can cause rare but fatal neurologic complications. We hypothesized that using a dose of local anesthetic lower than seizure threshold during cervical TFEB would not be associated with seizure activity in cases of accidental intra-arterial injection. Methods: Patients were randomized to one of two groups: group I received injections of 1mL of 1% lidocaine mixed with dexamethasone 2.5mg (n=15), and group II received 1mL of 0.125% lidocaine mixed with dexamethasone 2.5mg (n=15). When the numeric rating scale (NRS) for pain was greater than 3, cervical TFEBs were performed three times at 2-week intervals. Patients were evaluated up to 3 months. Results: Thirty patients with cervical radicular pain were enrolled in this study. The NRS pain score on the day of procedure and at 2 weeks, 4 weeks, 6 weeks, and 3 months following the initial procedure were similarly significantly reduced in both groups. The total number of procedures performed and the outcomes evaluated according to Odom's criteria at the 3-month follow-up visit were not different between groups. Overall, 73.3% and 80% patients in groups I and II, respectively, rated the degree of their symptom relief as excellent or good. Conclusion: Cervical TFEB performed using 0.125% lidocaine with dexamethasone achieved similar satisfactory effects as 1% lidocaine with dexamethasone for the treatment of cervical radicular pain. Therefore, the use of low-dose lidocaine with dexamethasone is reasonable for cervical TFEB, as this may reduce the incidence of rare but fatal complications.