Comparison of Intravascular Injection Incidences and Technical Easiness Between Anteroposterior and Oblique Approaches During S1 Transforaminal Epidural Injection

Abstract

BACKGROUND: Transforaminal epidural injection (TFEI) is a useful intervention for radicular leg pain. Compared to TFEI in lumbar level, S1 TFEI is reported to have higher incidence rates of intravascular injection as well as technical difficulties.

OBJECTIVE: The purpose of this study is to compare the incidence rates of intravascular injection and foramen passage time between anteroposterior (AP) and oblique (OB) approaches.

STUDY DESIGN: Prospective randomized trial.

SETTING: An interventional pain management practice in South Korea.

METHODS: One hundred forty-seven patients receiving S1 TFEI for radicular leg pain were randomly assigned to one of 2 approach methods (AP view vs OB view). For S1 TFEI in the OB view group, lineup of the L5-S1 endplate was performed by adjusting the cephalad-caudad tilt. Then C-arm was rotated at an ipsilateral oblique angle, approximately 10° to 15°. After final confirmation of intravascular injection with real time fluoroscopy, the foramen passage time and amount of radiation exposure during S1 TFEI were measured.

RESULTS: The incidence rate of intravascular injection in the AP view group was 24.2% (24/99), whereas that of intravascular injection in the OB view group was 10.1% (17/99, P = 0.008). The radiation dose required to pass the S1 foramen was significantly higher in the AP view group than in the OB view group (51.3 ± 27.2 cGy/cm2 vs 41.0 ± 17.0 cGy/cm2, P = 0.002). The foramen passage time during S1 TFEI was significantly higher in the AP view group than in the OB view group (103.5 ± 44.1 second vs 84.9 ± 21.0 second, P = 0.001). The failure rate of S1 TFEI was significantly higher in the AP view group than in the OB view group (13% vs 4%, P = 0.022).

LIMITATION: The physicians involved in the present study were not blinded to the type of approach method (AP view vs OB view) by fluoroscopy.

CONCLUSION: Our study demonstrated reduced incidence rates of intravascular injection and reduced foramen passage time and radiation dosage with the use of OB view method during S1 TFEI.