Medline ® Abstract for Reference 77

UNLABELLED: BACKGROUND AND OBJECTIVES The goal of this study was to evaluate the analgesic effects of intrathecal versus epidural methylprednisolone acetate (MPA) in patients with intractable postherpetic neuralgia (PHN).

METHODS: We studied 25 patients with a duration of PHN of more than 1 year. The patients were randomly allocated to one of two groups: an intrathecal group (n = 13) and an epidural group (n = 12). Sixty milligrams of MPA was administered either into the intrathecal or the epidural space four times at 1-week intervals depending on the treatment group. Continuous and lancinating pain and allodynia were evaluated by a physician unaware of group assignment with a 10-cm visual analogue scale before treatment, at the end of treatment, and 1 and 24 weeks after treatment. In addition, cerebrospinal fluid (CSF) was obtained for measurement of interleukin (IL)-1beta, -6, and -8 and tumor necrosis factor-alpha before and 1 week after treatment.

RESULTS: We found marked alleviation of continuous and lancinating pain and allodynia in the intrathecal group (P<.001). The improvements were much greater in the intrathecal group than in the epidural group at all time points after the end of treatment (P<.005). IL-8 in the CSF decreased significantly in the intrathecal group as compared to the epidural group at the l-week time point (P<.01), whereas the other cytokines were undetectable.

CONCLUSIONS: Our results suggest the effectiveness of intrathecal as compared to epidural MPA for relieving the pain and allodynia associated with PHN. Also, our findings, together with the decrease in IL-8, may indicate that intrathecal MPA improves analgesia by decreasing an ongoing inflammatory reaction in the CSF.