A Novel Approach to Atlanto-Occipital (AO) Joint Injection: A Cadaveric Study.

BACKGROUND

Atlanto-occipital (AO) joint instability and arthrosis are significant contributors to cervicogenic headaches and related disability. Injection and radiofrequency treatment of the AO joint are innovative approaches. However, the literature providing guidance on safe access to these joints remains sparse. The AO joint presents a high-risk target for interventions due to its proximity to the vertebral artery (VA), potentially compromising vascular supply to the cord, brainstem, cerebellum, and occipital lobe.

OBJECTIVES

We describe the technical details of a novel fluoroscopy-guided AO joint injection and evaluate the safety using a cadaveric model.

STUDY

DESIGN

Cadaveric study.

SETTING

Department of Pathology, Forensic and Insurance Medicine, Semmelweis University, Faculty of Medicine.

METHOD: Ten AO joints from five prone cadavers were targeted for injection. A far posterolateral needle entry targeting the anterolateral aspect of the AO joint was employed, guided by fluoroscopy. Intra-articular spread was confirmed with contrast medium. Subsequent dissections were conducted to examine the relationship between the VA and the needle trajectory and position to assess safety.

RESULTS

All needles were accurately placed within the AO joints and avoided the VA and adjacent critical structures, confirming the anatomical feasibility of the technique.

LIMITATIONS: The small sample size may not reflect the diversity of live patient anatomy. Additionally, the use of cadavers precludes assessment of physiological responses to injections, potentially limiting the direct applicability of findings to live patients.

CONCLUSIONS

This study describes a reproducible fluoroscopy-guided approach to the AO joint. Targeting the anterolateral aspect of the joint allowed accurate needle placement while maintaining separation from the VA and other critical structures in this cadaveric model, supporting further clinical evaluation of the technique.