Can Repeat Injection Provide Clinical Benefit in
Patients with Lumbosacral Diseases When First
Epidural Injection Results Only in Partial Response?
Authors: Lee Jung Hwan 
Published: February 2021

Background: Epidural steroid injection (ESI) is known to be an effective treatment for lower back
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 a single ESI,
there has been little evidence supporting the usefulness of repeat injections in cumulative clinical pain
reduction.
Objectives: The purpose of this study 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 that provided by intermittent injection performed only when pain was aggravated.
Study Design: An Institutional Review Board (IRB)-approved retrospective chart review.
Setting: Spine hospital.
Methods: Two hundred and four patients who had underwent transforaminal ESI (TFESI) for
treatment of lower back and radicular pain due to HIVD or SS and could be followed-up for one year
were enrolled. We divided the patients into 2 groups. Group A (N = 108) comprised partial responders
(NRS ≥ 3 after first injection) who underwent repeat injection at a prescribed interval of 2 to 3 weeks
after the first injection. Group B (N = 96) comprised partial responders who did not receive a repeat
injection at the prescribed interval, but received repeat injections only for aggravation of pain. Various
clinical data including total number of injections during one year, duration of NRS < 3 during one
year (NRS < 3 duration), and time interval until aggravation of pain required additional injections after
repeat injection in group A, or after first injection in group B (time to reinjection), were assessed. These
data were compared between groups A and B in terms of total population, HIVD, and SS.
Results: In the whole population, the mean time to reinjection was 6.09 ± 3.02 months in group A
and 3.69 ± 2.07 months in group B. The NRS < 3 duration was 9.72 ± 2.86 months and 6.2 ± 2.61
months in groups A and B, respectively. In HIVD patients, the mean time to reinjection was 5.82 ±
3.23 months in group A and 3.84 ± 2.34 months in group B, and NRS < 3 duration was 9.40 ± 3.34
months and 7.15 ± 2.40 months in groups A and B, respectively. In SS patients, the mean time to
reinjection was 6.40 ± 2.85 months in group A and 3.59 ± 1.88 months in group B, and NRS < 3
duration was 9.98 ± 2.41 months and 5.52 ± 2.55 months in groups A and B, respectively. Group A
had a significantly longer time to reinjection and longer NRS < 3 duration than group B in the whole
population, HIVD, and SS.
Limitation: Retrospective design.
Conclusions: Repeat TFESI conducted at 2- to 3-week intervals after the first injection in partial
responders contributed to greater clinical benefit compared to intermittent TFESI performed only upon
pain aggravation. These benefits were observed in patients with HIVD and in those with SS, irrespective
of severity or location of disease.
Key words: Epidural steroid injection, transforaminal approach, repeat injection, numeric rating
scale, lumbar spine, herniated intervertebral disc, spinal stenosis, partial pain reduction