Clinical studies evaluating AO joint injections
| Author, year | Patient population | Design | Results | Comments |
| Busch and Wilson, 1989168 | 25 pts with head and neck pain of which 2 pts received LA and steroid AO and AA joint injections | Retrospective | Pain relief in both cases ranged from 3 weeks to 4 months (1 patient received serial injections) | No reported adverse events other than transient ataxia and worsening pain for 24–48 hours. Fluoroscopically-guided AO and AA injections performed concurrently |
| Dreyfuss et al 1994159 | 3 pts who received fluoroscopically-guided AO injections | Case series | Pain relief in all 3 pts ranging from 6 to 12 months | No reported adverse events. Multiple concurrent injections limits generalization |
| Lee et al 2015165 | 29 pts with refractory headache and neck pain and findings suggestive of AO joint pain. Pts with ≥50% pain relief after diagnostic AO block underwent fluoroscopically-guided AO joint injections with LA and steroid | Prospective observational study | 20 of 24 (83%) pts had a positive diagnostic block. Pain scores and function improved from baseline at 2-month follow-up | Pts received two AO joint injections 1 week apart. No reported adverse events |
| Centeno et al 2018158 | 10 pts received bilateral AO joint injections | Case series | All injections reported as ‘successful’ with no adverse events | Head flexed to open up joint and rotated ipsilaterally to displace vertebral artery medially. Injectate composition not reported. Effectiveness outcome measures and follow-up period not reported |
| Shin et al 2018171 | 23 pts with chronic upper cervical pain, pain score ≥3/10, and ≥50% pain relief after diagnostic AO joint block received either AO joint injection with LA and steroid (n=11) or pulsed RF of the AO joint (n=12) | Randomized comparative-effectiveness trial | Pain score improved from baseline with sustained relief at 6 months with no differences between groups | Between 60% and 70% of pts achieved >50% pain relief through 6-month follow-up. Study not blinded. No adverse events reported |
| El Abd et al 2008166 | Single patient with right-sided neck pain and headache due to congenital fusion of AO joints bilaterally. Two injections done with LA and steroid | Case report | 2 weeks after second therapeutic injection, patient reported 75% improvement. At 6 and 12 month follow-ups, pain reduction persisted | Authors reported no noticeable improvement in ROM |
AA, atlanto–axial; AO, atlanto–occipital; LA, local anesthetic; pts, patients; RF, radiofrequency; ROM, range of motion.