To investigate the clinical effectiveness and complications of caudal epidural steroid injections in the treatment of sciatica in patients with an MRI proven sacral tarlov cyst.

A Prospective case control study. All patients with corresponding radicular pain received a course of three caudal epidural steroid injections, two weeks apart and patients were reviewed at 3 months, 6 months and 1 year interval in a dedicated epidural follow up clinic. Data including demographics, MRI results, diagnosis and complications were documented. Outcome measures included the Oswestry Disability Questionnaire (ODQ), the visual analogue score (VAS) and the hospital anxiety and depression (HADS) score.

Overall patient satisfaction was recorded on a scale of 0-10.

38 patients with a sacral tarlov cyst were compared to a matched control group. In the sacral cyst group, mean VAS for axial pain reduced from 5.859 to 2.59 at three months (p<0.001). VAS for limb pain reduced from 6.23 to 2.53(<0.005). Mean ODI reduced from 45.49 at first visit to 21.98 at 3 months. Mean HADS also improved from 17 to 7. There was no statistical difference between the two groups. BMI did not affect the outcome in either group.

Based on our study, we conclude that presence of a sacral tarlov cyst is not a contraindication to caudal epidural steroid injection, as comparable significant improvement in both axial and limb pain in the short and intermediate periods was achieved without any major complications.