BACKGROUND: Epidural steroids injections (ESI) are frequently used to treat lumbar radicular pain. Although different volume have been used for interlaminar ESI in adults, there is no controlled trial comparing the effect of different volumes on pain relief for the same dose of steroid .
OBJECTIVE: To compare the effect of increase in volume of epidural drug on pain relief in lumbar ESI.
STUDY DESIGN: Randomized double blind trial SETTING: Pain OR of a tertiary care centre METHODS: Sixty patients were randomly allocated to 1 of 3 groups: Group A (4 mL), Group B (6 mL), and Group C (8 mL). Pain was evaluated using visual analog scale (VAS) and improvement in disability using modified Oswestry Disability Questionnaire scores (MODQS) at 2, 4, 8, 12, and 24 weeks. Patients having less than 50% pain relief from baseline received an additional epidural injection of the same volume with a maximum of 3 injections at least 15 days apart. The primary objective of the study was incidence of patients attaining more than 50% pain relief at 6 months. Secondary outcome included MODQS and pattern of spread of iodinated contrast on fluoroscopy.
RESULTS: At the end of 6 months, there was no significant difference in the effective pain relief between the 3 groups (Group A-16/22 (72.7%), Group B-15/20 (75%), Group C-13/18 (72.2%); P = 0.98, chi- square test). All groups demonstrated a significant reduction in mean VAS scores. There was no significant intergroup difference in VAS sores and MODQS at all the time intervals. The pattern of contrast spread did not differ between the 3 groups.
LIMITATION: Not a placebo controlled trial.
CONCLUSIONS: An increase in volume of the injectate from 4 mL to 8 mL did not increase the efficacy of interlaminar ESI.
KEY WORDS: Epidural steroid, volume, low back pain, interlaminar.
This was a trial looking at patients with lumbosacral radical arm pain for at least three months duration which failed to respond to physical therapies and medications. Patients with facet joint related pain, lumbar canal stenosis, contraindications to a lumbar epidural steroid or a epidural steroid injection in the previous three months were excluded. Three volumes of epidural steroid injection 4, 6 and 8 mls were used an follow up at 2, 4, 8, 12 and 24 weeks with VAS Pain reduction as the primary outcome. Sixty patients were recruited and randomly allocated to one of the three groups of epidural steroid injections. At 24 weeks, there was no difference between the three groups for the primary outcome suggesting that altering the volume of lumbar epidural steroid injection has minimal impact on pain reduction. I tend to prefer a targeted root sleeve injection for radical pain rather than a lumbar epidural steroid injection.
This article does not add anything new to the already known facts. Most pain physicians use the middle volume of the study (5-6 mls) and there seems to be no significant advantage in varying this volume by 2 mls, more and less, in terms of patient safety and any clinical outcome.
This study reports an interesting comparison of the effect change of epidural drug on pain relief in lumbar ESI, as the volume was changed. The conclusion is that there were no significantly different results in pain relief on increasing the volume of drug in midline interlaminar approach, which provides a pivotal piece of information to the field. In addition, the authors reported a whole paragraph mentioning the study limitations. Firstly, there was no placebo group. Secondly, contrast and drug injected had different viscosities and epidural flow characteristics. Thirdly, authors did not define the injection speed. Fourthly, the number of patients used in each group was different. Despite these understandable and justifiable limitations, data reported matter in the field, so I believe this manuscript represents a valid piece of information.
It is a good RCT which shows that change in volume has no side effects.
This is a well conducted and well written randomized study which documents definitely that pain relief following epidural steroids injections is not affected by the drug dose. The most important limitation includes the absence of a placebo-controlled group, as adequately stated in the text.