Can repeat injection provide clinical benefit in patients with cervical disc herniation and stenosis when the first epidural injection results only in partial response?

Epidural steroid injection (ESI) is known to be an effective treatment for neck or radicular pain due to herniated intervertebral disc (HIVD) and spinal stenosis (SS). Although repeat ESI has generally been indicated to provide more pain relief in partial responders after single ESI, there has been little evidence supporting the usefulness of this procedure. The purpose of this study, therefore, was to determine whether repeat ESI at a prescribed interval of 2 to 3 weeks after the first injection would provide greater clinical benefit in patients with partial pain reduction than intermittent ESI performed only when pain was aggravated. One hundred eighty-four patients who underwent transforaminal ESI (TFESI) for treatment of axial neck and radicular arm pain due to HIVD or SS and could be followed up for 1 year were enrolled. We divided the patients into 2 groups. Group A (N = 108) comprised partial responders (numeric rating scale (NRS) ≥ 3 after the first injection) who underwent repeat injection at a prescribed interval of 2 to 3 weeks after the first injection. Group B (N = 76) comprised partial responders who did not receive repeat injection at the prescribed interval, but received intermittent injections only for aggravation of pain. Various clinical data were assessed, including total number of injections during 1 year, NRS duration of <3 during 1 year (NRS < 3 duration), and time interval until pain was increased to require additional injections after repeat injection in Group A, or after first injection in Group B (time to reinjection). Groups A and B were compared in terms of total population, HIVD, and SS. In the whole population, HIVD subgroup, and SS subgroup, patients in Group A required significantly fewer injections to obtain satisfactory pain relief during the 1-year follow-up period. Group A showed a significantly longer time to reinjection and longer NRS < 3 than Group B did. Repeat TFESI conducted at 2- to 3-week intervals after the first injection in partial responders contributed to greater clinical benefit compared with intermittent TFESI performed only upon pain aggravation, with fewer TFESI sessions.