Table 4.

Studies evaluating pain referral patterns for atlanto–occipital and atlanto–axial injections

Author, year	Patients	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 joints injections	Case series/ retrospective	Pain relief in both cases ranged from 3 weeks to 4 months (one patient received serial injections). AA and AO joints may be a source of occipital headache refractory to conservative therapy	25 pts treated but only 2 cases described
Aprill et al 20025	34 pts with history of occipital or SO pain, tenderness over C1 and decreased ROM of AA joint treated with AA IA injection of LA and steroid	Prospective observational	21 of 34 (62%) pts experienced complete relief (≤1/10 on VAS) for 2 hours following the injection	No control group, no sham injection or other joints examined
Narouze et al 200762	32 pts with clinical exam consistent with AA-mediated pain treated with AA IA injection of LA and steroid	Retrospective study	15 of 32 (46.8%) pts obtained complete pain relief (NRS pain score=0), 26/32 (81.2%) pts with ≥50% pain relief	No control or comparison groups or other joints examined
Lee et al 2015165	24 pts with headache and/or SO pain, SO tenderness, and limited range of lateral bending with rotation at the AO joint, treated with AO IA injection of LA. Responders received IA LA and steroid injection	Prospective observational	20 of 24 (83%) pts had ≥50% pain relief for 30 min following the injection. 18 of 20 (90%) pts had a 2-point or greater reduction in pain score	No control or sham groups, 2 month follow-up. 14 of 14 pts with headache had ≥50% relief. 15 of 20 pts with posterior neck pain had ≥50% relief.13 of 17 pts with shoulder/arm pain had ≥50% relief
Dreyfuss et al 199450	5 asymptomatic volunteers (no history of headache or neck pain) received one AO and one AA provocative injection with contrast	Prospective observational	AO injections provoked variable referred pain from the level of the C5 spinal segment through the vertex of the head. AA injections were more consistent, producing pain only in the SO region	Provoked pain described as dull, deep ache, or heavy pressure
Cooper et al 200749	5 pts with neck or SO headache treated with AA injection of LA (one patient had bilateral injections)	Prospective observational	Responders had 100% pain relief or relief in a definable portion of the patient’s area of pain. 5 out of 134 (3.7%) total pts with positive cervical diagnostic blocks had C1–2 as a source	AA injections relieved pain in the neck up to the vertex of the head, occasionally in the region of the ear and orbit
Fukui et al 199651	10 pts with neck pain were treated with AO and 10 pts with neck pain were treated with AA IA injections with LA and steroid	Prospective observational	AO and AA injections produced pain in the posterior occiput and posterolateral cervical spine (areas over the mastoid process)	Pain relief was not reported, although LA and steroid was used in the provocative injection
Ehni and Benner, 198456	7 pts with SO pain, tenderness and pain during rotation were treated with AA IA injection of LA and steroid	Case series	AA injections produced immediate relief	No details provided regarding injection technique. No quantification of pain relief was provided

AA, atlanto–axial (C1–C2) joint; AO, atlanto–occipital (C0–C1) joint; IA, intra-articular; LA, local anesthetic; MBB, medial branch blocks; NRS, numerical rating scale; pts, patients; ROM, range of motion; SO, suboccipital.