Study designs of evaluations included in the review
Controlled and uncontrolled studies were eligible for inclusion. Case reports and descriptive reports were excluded.
Specific interventions included in the review
Studies that assessed local anaesthetic injections, placebo- controlled injections, controlled comparative local anaesthetic sacroiliac joint injections, sacroiliac joint infections with local anaesthetic and steroid, and radiofrequency neurotomy (thermal and pulsed). Studies that assessed single injections, non-fluoroscopic/non-radiographically guided injections, and surgical interventions were excluded. All included studies on diagnostic sacroiliac joint injections involved a screening lidocaine injection performed under fluoroscopic guidance and used a comparative controlled local anaesthetic technique in patients with a positive response. Details about which provocation tests and in which combination these were used were not reported for the included studies. Therapeutic injections in the included studies involved steroids, corticosteroids, radiofrequency strip lesions, pulsed radiofrequency after local anaesthetic injection, or placebo.
Reference standard test against which the new test was compared
Inclusion criteria relating to the reference standard used to establish a diagnosis of painful lumbar sacroiliac joint were not specified. A variety of reference standards were used by the included diagnostic studies: >50%, >70%, >75%, >80%, or >90% pain relief to a single joint block alone or combined with concordant pain provocation or continued pain relief lasting at least 1, 2 or 4 hours.
Participants included in the review
Studies of patients with low back pain with or without leg pain of at least 3 months' duration, who had failed conservative management and had sufficient pain to be referred to a pain specialist or spinal injectionist, were eligible for inclusion.
Outcomes assessed in the review
Studies in which the main outcome was pain relief of at least 50% were eligible for inclusion. Studies with a duration of follow-up of less than 3 months were excluded. For therapeutic injections, the primary outcome measure was initially defined as significant (>50%) pain relief. Other outcome measures reported included functional improvement, psychological improvement and work status. For the included studies on intra-articular injections, short-term relief was defined as less than 6 weeks and long-term relief as greater than 6 weeks. For radiofrequency neurotomy, short-term relief was defined as less than 3 months and long-term relief as greater than 3 months. For diagnostic interventions, the individual authors' description of pain relief was accepted.
How were decisions on the relevance of primary studies made?
The authors stated that one reviewer assessed studies for inclusion and that three reviewers evaluated the studies. It was unclear exactly what this meant.