BACKGROUND: Lumbar epidural steroid injection (LESI) is an effective treatment for low back pain. However, it may result in increased blood glucose levels, decreased plasma cortisol concentrations, and suppression of the adrenocorticotropic hormone axis.
OBJECTIVE: We investigated the effects of 4 mg and 8 mg of dexamethasone as an LESI on back pain and the resulting changes in serum cortisol and glucose levels.
STUDY DESIGN: Prospective study.
SETTING: Department of Anesthesiology and Pain Medicine, Neurosurgery at Daegu Wooridul Spine Hospital.
METHODS: Sixty-three patients were randomized into 2 LESI groups: one received 4 mg of dexamethasone (n = 25) and the other received 8 mg of dexamethasone (n = 28). Visual analog scale (VAS) scores and the Oswestry Disability Index (ODI) were determined. In addition, serum cortisol and glucose concentrations were measured before treatment, at the second LESI (one month follow-up), and at 2 months. All patients received LESI.
RESULTS: Blood glucose and serum cortisol concentrations were not significantly different within a group and between groups. There was no difference in serum cortisol and glucose levels, VAS, and ODI between the first LESI and second LESI in both groups. The VAS and ODI were reduced in both groups and the difference between groups was not statistically significant.
LIMITATIONS: The dexamethasone dosage was not variable; hence, we could not use larger doses of dexamethasone. Secondly, the blood draw interval was longer in this study than in previous studies.
CONCLUSION: After the first lumbar epidural injection of either 4 mg or 8 mg of dexamethasone, there was a reduction in pain in both groups. There was no significant difference in serum cortisol and glucose levels before treatment and during follow-up. Therefore, 4 mg or 8 mg of dexamethasone can be considered a treatment for patients who have low back pain.
This is a small study of a comparison that most anesthesiologists would not care much about. While changes in blood sugar related to a single dose of dexamethasone in a lumbar epidural injection have been reported, the clinical significance of this is minimal. Pain practitioners will be interested to note the lack of adverse events, as well as no difference between the doses in the pain relief achieved.
As a neurosurgeon, these results do not add new information to the way I should manage patients with low-back pain.