Transforaminal vs Interlaminar Epidural Steroid Injection for Acute-Phase Shingles: A Randomized, Prospective Trial.

BACKGROUND: The acute phase of shingles is characterized by severe pain, and one of the complications of shingles known as postherpetic neuralgia (PHN) is associated with prolonged pain. Although factors predicting the development of PHN, as well as its preventative measures, have been investigated, there is no single treatment effective for PHN. Some studies showed effectiveness of epidural injection to alleviate pain associated with acute-phase shingles. In these studies, epidural injection was performed by interlaminar (IL) approach. However, transforaminal (TF) approach may be more effective as it enables injection of steroids and local anesthetics closer to the dorsal root ganglion where inflammation primarily occurs. There have not been any studies comparing the analgesic effects of epidural injection approaches for pain associated with acute-phase shingles.

OBJECTIVE: We compared the analgesic effects of IL and TF epidural injection approaches for pain associated with acute-phase shingles.

STUDY DESIGN: We conducted a randomized prospective trial.

SETTING: Nara Medical University Hospital, Department of Anesthesiology.

METHODS: Forty patients with acute-phase shingles were randomly assigned to receive epidural steroid injections by TF or IL approaches. Patients were evaluated at the baseline, as well as at 1 month and 3 months after the treatment using the VAS and SF-36 scores. Patients with VAS score of over 40 at the 3-month follow-up were considered as having PHN, and the number of patients with PHN was compared between the IL and TF groups.

RESULTS: Except the mental component of the SF-36 score and severity of skin rash, patient characteristics were not significantly different between the groups. VAS scores at 1 and 3-month follow-up were significantly lower than those at the baseline, and there was no difference between the groups. All SF-36 scores were not significantly different between groups at 1- and 3-month. There was no significant difference in the occurrence of PHN between the groups.

LIMITATIONS: We had a small sample size that did not reach the number of patients needed by the power analysis in the study. Then, our follow-up period of 3 months was relatively short.

CONCLUSIONS: VAS scores, the SF-36 RCS and MCS scores improved in both groups, however, there was no difference in the analgesic effects of the IL and TF epidural steroid injections at 1 and 3 months for acute-phase shingles patients.

KEY WORDS: Shingles epidural steroid injection interlaminar approach; transforaminal approach, fluoroscopic, postherpetic neuralgia, VAS, SF-36.