Table 11.

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.