Therapeutic effect and outcome predictors of sciatica treated using transforaminal epidural steroid injection.

OBJECTIVE: The objectives of this retrospective study were to assess the therapeutic effect of transforaminal epidural steroid for sciatica and to identify outcome predictors.

MATERIALS AND METHODS: Transforaminal epidural steroid injections were performed in 248 patients from June 2003 to May 2004. Fifty-six patients (33 women, 23 men; mean age, 53.3 years; age range, 30-83 years) were included. Therapeutic effects were evaluated 2 weeks after injection. The possible outcome predictors were as follows: intraepineural or extraepineural injection, saddle-type distribution pattern (contrast material distributed rostrally to the epidural portion of the preganglionic nerve root) or not saddle type, cause of sciatica (spinal stenosis vs herniated disk), patient age, patient sex, and duration of sciatica (acute or subacute [< 6 months] vs chronic [> 6 months]). The relationships between possible outcome predictors and therapeutic effects were analyzed. Statistical analysis was performed using Fisher's exact test, the chi-square test, and multiple logistic regression analysis.

RESULTS: Forty-three (76.8%) of the 56 patients achieved a satisfactory result 2 weeks after transforaminal epidural steroid injection. Nineteen (65.5%) of the 29 patients treated by intraepineural injection and 24 (88.9%) of the 27 patients treated by extraepineural injection achieved a satisfactory result, and this difference was significantly different (p < 0.05). Other possible predictors of a better outcome were identified--that is, saddle-type pattern of contrast distribution, a herniated disk, and sciatica of less than 6 months' duration. Multiple regression analysis showed that the only factor significantly associated with outcome was the type of injection (p = 0.04, odds ratio: 5.01).

CONCLUSION: Transforaminal epidural steroid is an effective tool for managing sciatica, and an extraepineural injection may be a predictor of a better outcome for sciatica treated using transforaminal epidural steroid.