| Type of study: | Retrospective case notes data analysis |
| Sample: | Patients with chronic low back pain |
| Setting: | Pain clinic in a district general hospital |
| Study period: | April 2010 to April 2011 |
| Outcome measures: | Pain relief of 50% or greater, duration of pain relief 6 weeks post injection |
| Inclusion criteria: | Patients with SIJ injection only |
| Exclusion Criteria: | Patients who received SIJ injections plus other interventional procedures simultaneously. |